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PVF User's Guide

1. if x i gt 0 0 E 2 0 else E 2S EN endif EE ee burg enddo V E where t is assigned on every iteration of the loop However there are cases where a scalar may be privatizable If it is used after the loop it is unsafe to parallelize Examine this loop do i LN if x i gt 0 0 t x i Wicd yy Stes es endif enddo We E where each use of t within the loop is reached by a definition from the same iteration Here t is privatizable but the use of t outside the loop may yield incorrect results since the compiler may not be able to detect on which iteration of the parallelized loop t is assigned last The compiler detects the above cases Where a scalar is used after the loop but is not defined on every iteration of the loop parallelization will not occur If you know that the scalar is assigned on the last iteration of the loop making it safe to parallelize the loop a pragma is available to let the compiler know the loop is safe to parallelize Use the following C pragma to tell the compiler that for a given loop the last value computed for all scalars make it safe to parallelize the loop cpgi l safe _lastval In addition a command line option Msafe_lastval provides this information for all loops within the routines being compiled essentially providing global scope Optimization Directives 127 unroll nounroll The directive nounroll is used to disable loop unrolling and unroll to enable unrolling The
2. Minfo and your code contains loops that can be vectorized the compiler reports relevant information on the optimizations applied When a PGI compiler command is invoked with the Mvect option the vectorizer scans code searching for loops that are candidates for high level transformations such as loop distribution loop interchange cache tiling and idiom recognition replacement of a recognizable code sequence such as a reduction loop with optimized code sequences or function calls When the vectorizer finds vectorization opportunities it internally rearranges or replaces sections of loops the vectorizer changes the code generated your source code s loops are not altered In addition to performing these 30 Optimization amp Parallelization loop transformations the vectorizer produces extensive data dependence information for use by other phases of compilation and detects opportunities to use vector or packed Streaming SIMD Extensions SSE instructions on processors where these are supported The Mvect option can speed up code which contains well behaved countable loops which operate on large REAL REAL 4 REAL 8 INTEGER 4 COMPLEX or COMPLEX DOUBLE arrays in Fortran However it is possible that some codes will show a decrease in performance when compiled with Mvect due to the generation of conditionally executed code segments inability to determine data alignment and other code generation factors For this reason it is
3. Table A 12 Fortran and C C Representation of the COMPLEX Type Fortran Type C C Type Size bytes COMPLEX x struct float r I x 8 COMPLEX 8 x struct float r I x 8 COMPLEX 16 x struct double dr di x 16 DOUBLE COMPLEX x struct double dr di x 16 C C arrays and Fortran arrays use different default initial array index values By default C C Run time Environment 169 arrays start at 0 and Fortran arrays start at 1 A Fortran array can be declared to start at zero Another difference between Fortran and C C arrays is the storage method used Fortran uses column major order and C C use row major order For one dimensional arrays this poses no problems For two dimensional arrays where there are an equal number of rows and columns row and column indexes can simply be reversed Inter language function mixing is not recommended for arrays other than single dimensional arrays and square two dimensional arrays Structures Unions Maps and Derived Types Fields within Fortran structures and derived types and multiple map declarations within a Fortran union conform to the same alignment requirements used by C structures Common Blocks A named Fortran common block can be represented in C C by a structure whose members correspond to the members of the common block The name of the structure in C C must have the added underscore For example the Fortran common block INTEGE
4. To set this option in PVF use the Fortran Optimization Inlining property Usage In the following example the compiler extracts functions that have 500 or fewer statements from the source file myprog f and saves them in the file extract il pgf95 Mextract 500 oextract il myprog f In the following example the compiler inlines functions with fewer than approximately 100 statements in the source file myprog f and writes the executable code in the default output file a out pgf95 Minline size 100 myprog f Cross reference o M lt pgflag gt Fortran Language Controls This section describes the M lt pgflag gt options that affect Fortran language interpretations by the PGI Fortran compilers These options are only valid to the pgf77 and pgf95 compiler drivers Syntax Mbackslash Mnobackslash Mdclchk Mnodclchk Mdefaultunit Mnodefaultunit Mdlines Mnodlines Mdollar char Command Line Options the compiler treats the backslash as a normal character and not as an escape character in quoted strings the compiler recognizes a backslash as an escape character in quoted strings in accordance with standard C usage the compiler requires that all program variables be declared the compiler does not require that all program variables be declared the compiler treats as a synonym for standard input for reading and standard output for writing the compiler treats as a syno
5. c cccccccceeeeeeeeseneeeeeeeeeeeaaeseeeeeeseaaeeeeeeeeseaeeeseneees 144 Register Allocation EE 150 Standard Stack Frames j2 ctvid snaar a a iaa e aa aa aara Taaa 151 Stack Contents for Functions Returning struct union eseeseeeeeeeeee 154 Integral and Pointer Arguments essessseeeesseersssirrsssrirnnsninrnnsstnnnnssrnennne 155 Floating point ArgumeMS saone aa aa aie aaa a ER AAIE 155 Structure and Union Arguments cccccccceeeeeeeeeeeeceeeeeeeeeeseaeeseneeeeeeaeeee 156 Register AlloCation sie keiev egeg a BOES deeg 159 Standard Stack Frame AANEREN 160 Register Allocation for Example AA 163 Win64 Fortran Fundamental Types ssssssssseeesssssrrrssssrrsssrirrsssrirrnnssrrnnnnne 166 Fortran and C C Data Type Compatbiltv neern 169 Fortran and C C Representation of the COMPLEX Type 169 vii viii Preface This guide is part of a set of manuals that describe how to use The Portland Group PGI Fortran compilers and program development tools integrated with Microsoft Visual Studio These tools combined with Visual Studio and assorted libraries are collectively known as PGI Visual Fortran or PVE PVF can be used to edit compile debug optimize and profile serial and parallel applications for x86 Intel Pentium II III 4 M Intel Centrino Intel Xeon AMD Athlon XP MP or x64 AMD Athlon64 Opteron Turion Intel EM64T Core 2 processor based systems This PVF User s Guide provides operating instructi
6. A separate frame pointer enables calls to routines that change the stack pointer to allocate space on the stack at run time e g alloca Some languages can also return values from a routine allocated on stack space below the original top of stack pointer Such a routine prevents the calling function from using Yorsp relative addressing to get at values on the stack If the compiler does not call routines that leave rsp in an altered state when they return a frame pointer is not needed and is not used if the compiler option Mnoframe is specified Run time Environment 163 The stack must always be 16 byte aligned except within the prolog and within leaf functions Variable Length Parameter Lists Parameter passing in registers can handle a variable number of parameters The C language uses a special method to access variable count parameters The stdarg h and varargs h files define several functions to access these parameters A C routine with variable parameters must use the va_start macro to set up a data structure before the parameters can be used The va_arg macro must be used to access the successive parameters For unprototyped functions or functions that use varargs floating point arguments passed in registers must be passed in both an XMM register and its corresponding general purpose register C Parameter Conversion In C for a called prototyped function the parameter type in the called function must match the argument type
7. Functions pass all integer valued arguments as words expanding or padding signed or unsigned bytes and halfwords as needed 154 Run time Environment Table A 4 Integral and Pointer Arguments Call Argument Stack Address g 1 2 3 void 0 1 8 ebp 2 12 ebp 3 16 ebp void 0 20 ebp Floating Point Arguments The stack also holds floating point arguments single precision values use one word and double precision use two The example below uses only double precision arguments Table A 5 Floating point Arguments Call Argument Stack Address h 1 414 1 2 998e10 word 0 1 414 8 Yebp word 1 1 414 12 ebp 1 16 ebp word 0 2 998e10 20 ebp word 1 2 998e10 24 ebp Structure and Union Arguments Structures and unions can have byte halfword or word alignment depending on the constituents An argument s size is increased if necessary to make it a multiple of words This may require tail padding depending on the size of the argument Structure and union arguments are pushed onto the stack in the same manner as integral arguments described above This provides call by value semantics letting the called function modify its arguments without affecting the calling function s object In the example below the argument s is a structure consisting of more than 2 words Run time Environment 155 Table A 6 Structure and
8. Keyword Completion Fortran keywords are supported with keyword completion When entering a keyword into the source editor typing lt CTRL gt lt SPACE gt will open a pop up list displaying the possible completions for the portion of the keyword entered so far Use the up or down arrow keys or the mouse to select one of the displayed items type lt ENTER gt or double click to enter the remainder of the highlighted keyword into the source Type additional characters to narrow the keyword list or use lt BACKSPACE gt to expand it 1 5 Setting Global User Options Global user options are settings that affect all Visual Studio sessions for a particular user regardless of which project they have open These options are set by accessing the Tools Options dialog PVF supports several global user settings which affect the directories that are searched for executables include files and library files These are accessed by selecting Tools Options to access the dialog then clicking on Projects and Solutions followed by PVF Directories in the dialog s navigation pane The PVF Directories page has two combo boxes at the top labeled Platform to allow selection of the platform for example x64 and Show directories for to allow selection of the search path to edit Search paths that can be edited include the Executable files path the Include and module files path and the Library files path In general it is good practice to ensure that all thr
9. The subroutine or function statement for the given subprogram has a different number of dummy arguments than appear in the call to the EXTERNAL name given W353 Subprogram is missing A call to a subroutine or function with this name appears but it could not be found or analyzed I354 Subprogram is not called No calls to the given subroutine or function appear anywhere in the program W355 Missing argument in call to A nonoptional argument is missing in a call to the given subprogram I356 Array section analysis incomplete Interprocedural analysis for array section arguments is incomplete some information may not be available for optimization I357 Expression analysis incomplete Messages 205 Interprocedural analysis for expression arguments is incomplete some information may not be available for optimization W358 Dummy argument is EXTERNAL but actual is not subprogram The call statement passes a scalar or array to a dummy argument that is declared EXTERNAL W359 SUBROUTINE passed to FUNCTION dummy argument The call statement passes a subroutine name to a dummy argument that is used as a function W360 FUNCTION passed to FUNCTION dummy argument with different result type The call statement passes a function argument to a function dummy argument but the dummy has a different result type W361 FUNCTION passed to SUBROUTINE dummy argument The call statement passes a function name to a dummy
10. Program units compiled with Mvect prefetch will not execute correctly on Pentium Pentium Pro or Pentium II processors They will execute correctly only on Pentium III Pentium 4 Xeon EMO4T AthlonXP Athlon64 or Opteron systems In addition the prefetchw instruction is only supported on AthlonXP Athlon64 or Opteron systems and can cause instruction faults on non AMD processors For this reason the PGI compilers do not generate prefetchw instructions by default on any target In addition to these sub options to Mvect several other sub options are supported See the description of Mvect in Chapter 4 Command Line Options for a detailed description of all available sub options 3 5 2 Vectorization Example Using SSE SSE2 Instructions One of the most important vectorization options is Mvect sse This section contains an example of the use and potential effects of Mvect sse When the compiler switch Mvect sse is used the vectorizer in the PGI Workstation compilers automatically uses SSE and SSE2 instructions where possible when targeting processors where these are supported This capability is supported by all of the PGI Fortran C and C compilers See table P 2 for a complete specification of which x86 and x64 processors support SSE and SSE2 instructions Using Mvect sse performance improvements of up to two times over equivalent scalar code sequences are possible In the program in Example 3 3 Vector operat
11. cccccccssseeeeeeeeeeeeeeeeeeeeeeeeeeeeeenseneeeeeeeeees 149 Win32 Programming Model cceeceeceeeeeceeeeeeeeneeeeeeeeaeeeeeeeaaeeeeneeaas 149 Function Calling Sequence c ccceceeeeeeeeeeeeteeeeeaeeeeecaeeeseneeeteeeeteeeeend 149 Register Usage Conventions c ccccccceeeeeeececeeeeeeeeeeseaeeeeeeeessaeeesennees 149 Function Return Values 152 Argument Passing esse cso aga ia i a ee eee 154 Win64 Programming Model cecceeeeeeeeeeeeeeeeeeneeeeeeeeeaeeeeeeeaaeeeeneeaas 158 Function Calling Sequence cetccececeeeeeeneeeeeeeeeeaeeeseaeeeseneeeteaeeeteaeeees 158 Function Return Values 161 Argument Passing leese Ee EE eed 162 Win64 Fortran Supplement c ccccceeeeeeeeeeeeeeeeeeeeeeaeeeseeeeeseaeeeteeeeeaas 165 Fortran Fundamental Types 0 cceccsecceeeeeceeeeeeeeeceeeeeeeeiaeeeeeeenaeeeeeneaa 166 Fortran Naming Conventions cccccccceeeeeeeeeeeeeeeeeeeesecaeeeeeeeeessaeeneneees 167 Fortran Argument Passing and Return Conventions sccceeeeeeees 167 Interlanguage Calling cccccceeeeceeeeceeeeeeeeeeeeeeeaaeeeeeeeeseaeeseeeeeessaeeneneees 167 E EC 173 Diagnostic Messages onnaa a aa A SEA RRE ANE EAA 173 Phase Invocation Messages eeeeceeeeeeeeeneeeeeeeeeaeeeeeeeaaaeeeeseeaaeeeeeeeaaes 174 Fortran Compiler Error Messages cccecceeeeeeeeeeeeeeeeaeeeeeeeeeteaeeneeeeee 174 Message Format enire niena T E T SCEeER 174 Message DC 174 For
12. Mimiakell ti oante e edel duer 84 MNO GINO SEENEN edEEkEE deed eeeuteee 83 Mnobackslash ccccccccccceceeeeeeesseesessssseees 71 Mpo bou Nd EE 82 Mnodaz e a a A 66 Minodel lew sic neeaae de a 71 Mnodetaultuntt 71 Mnodepenk iis castecssscccsstecsescceesccgatadeceanseteis 75 MNOGIINGS eeeeeeeseeeeecceeeeeeeceeneeesseseeeess 71 Mnofluehz m n ain 67 Mnofprelaxed c cccsecceceeseeeeseceessreereseees 75 Mnoframe eE E E E 77 MNOI4 oo cece ccc e eee eseeeseeceeeceeecceeneeseeseeeeeeess 78 Mnoiomuten 72 Mnolarge_arrays seeren 67 Mnolet 84 Salle EE 77 MNOMAIN EE 67 Mnontemporal AAA 67 Mnoonetrip 00 eee eeeeeeeseeeeneetesneeeeseneeseaeees 72 Mnoopenmp ssssessesssuesrrnrerenrrrrarernsernerrenens 84 MNOpGdll MAIN A 85 Mnoprefetch AAA 78 ae 78 MNOFBiNtriNSICS ce eeeeeeeseeeeeeeeeeeneeees 79 Mnorecurehye i icen nS 68 Mnoreentrant 68 Mnoref_externals sosnneeeesnee neern eee 68 Mnosave 72 Mnoscalarsse oooonnnnnnnnnnnnnnnneneneneseneeeeeeene 79 Mnosecond underscore 68 SMMOSQIMP peesiscsssscestegeetencscuseachadicsdesesneeenaciee 84 Mnosignextend AAA 68 Mnoemart asrandi 79 MNOStartup EE 69 gl e Le WEE 69 Mnostride0 ee 68 Mnounixlogical seese 72 Mno nroll iesti iirasiiussenisinieis 79 MNOUPCASEC eecceeesereeeeeeeeeseeeereneeeetseeens 73 MNOVECT s ei eet e 80 Mnovintr cc ceeeeeeseeeeeeeeeceeeeeceeeeeseseseceeeeess 81 SMOGUIC ls
13. Note that there can be significant arithmetic differences between calculations performed using x87 instructions versus SSE SSE2 By default all floating point data is promoted to IEEE 80 bit format when stored on the x87 floating point stack and all x87 operations are performed register to register 28 Optimization amp Parallelization in this same format Values are converted back to IEEE 32 bit or IEEE 64 bit when stored back to memory for REAL float and DOUBLE PRECISION double data respectively The default precision of the x87 floating point stack can be reduced to IEEE 32 bit or IEEE 64 bit globally by compiling the main program with the pc 32 64 option to the PGI Workstation compilers which is described in detail in Chapter 4 Command Line Options However there is no way to ensure that operations performed in mixed precision will match those produced on a traditional load store RISC UNIX system which implements IEEE 64 bit and IEEE 32 bit registers and associated floating point arithmetic instructions In contrast arithmetic results produced on Intel Pentium 4 Xeon AMD Opteron Athlon64 or Intel EM64T processors will usually closely match or be identical to those produced on a traditional RISC UNIX system if all scalar arithmetic is performed using SSE SSE2 instructions You should keep this in mind when porting applications to and from systems which support both x87 and full SSE SSE2 floating point arithmetic Many subtle iss
14. Optimization pass assembly optimizer no smartalloc add a call to the routine mallopt in the main rou Environment tine To be effective this switch must be specified when compiling the file containing the Fortran C or C main program standard causes the compiler to flag source code that does Fortran Language not conform to the ANSI standard nostrideO the compiler generates does not generate alter Code Generation nate code for a loop that contains an induction variable whose increment may be zero Command Line Options 65 pgflag Description Category unix uses UNIX calling and naming conventions for CodeGeneration Fortran subprograms no nounixlogical determines whether logical TRUE and FALSE Fortran Language are determined by non zero TRUE and zero FALSE values for unixlogical With nounixlogi cal the default 1 values are TRUE and 0 values are FALSE noJunroll controls loop unrolling Optimization noupcase determines whether the compiler allows upper Fortran Language case letters in identifiers varargs force Fortran program units to assume calls are to Code Generation C functions with a varargs type interface no vect do don t invoke the code vectorizer Optimization Following are detailed descriptions of several but not all of the M lt pgflag gt options outlined in the table above These options are grouped according the category that
15. Working with Inline Libraries eseeeeeeeeessserrrssssirrsssrinnnsrinrnnsreennsnns 99 Updating Inline Libraries Makefiles AAA 99 Error Detection during Inlining esssssssssrrresserresernnrnesrnnnnnesrnnnneeernnnneene 100 EXAMPE S nin n a a ee a E E daa de 100 Restrictions on MMN snererircuiiei ierreus ataa EEEa 101 OpenMP Directives for Fortran c cccsseeeeeeeeseseeeeeeeseeeeeneeeeees 103 Parallelization Directives 0 ee ccceeeeeecnceeeeeecneeeeeeeeaeeeeeeeaaeeeeseenaaeeeeenenaes 103 PARALLEL END PARALLEL 0 ceeeeceeeeeeeeeeneeeceneeeeeeeeeseeeeeeeaeeeeed 104 GRIFICAE END ERHALE ao aea T an agne mipana ataa anaana Eaa ETA 107 MASTER END MASTER cccececceceeeceeeeeeeeeeeeeeeeeeeeeseaaeeeeeeeesiaaeeseenees 108 SINGLE END SINGLE tee Ee eet erie 109 DO er END DOr kee dee ege enee A EE eae to 109 WORKSHARE END WORKSHARE 0 c ececeeeeeeeeeeceeeseeeeeeenaeeteaes 112 BARRIER WEE 112 Met ei 112 PARADE eene E tera tee AE die DE BEE 113 PARALLEL WORKSHARE eet ha oinaan a a Earias 114 SECTIONS END SECTIONS 0o eecccccceeeeeeeeeeeeeeeeeeeeeeeaeeeseneeeesnaeeeeaes 114 PARALLEL SECTIONS Ae Eegen EEN DEENEN eee eines 115 RD ERED ee ee eege Ee ete 116 ATOMIC dt mge nu ap iraan dates aara a raae aa oana aaa aaeeea 116 ELUSEN EE 117 TAREA DPR IVA TE e raa Ta raa at ieee Seed eat ai ee aaa 117 Run time Library Routines 0 2 ceeeeeceeeeeeenneeeeeeeeeeeeeeeetaeeeeeeeeaeeeeeeneaa 118 Enviro
16. by the DLLIMPORT statements so the def file should be empty touch obj2 def pgf95 c object2 95 d i d i ol 136 pgf95 Mmakeimplib o obj2 1lib object2 obj def obj2 def Libraries and Environment Variables d i touch obj3 def pgf95 c object3 95 pgf95 Mmakeimplib o obj3 1lib object3 obj def obj3 def d i d i Step 2 Create the DLLs using the import libraries obj3 lib and obj4 lib pgf95 Mmakedll o obj2 dl1l object2 obj defaultlib obj3 pgf95 Mmakedll o obj3 dll object3 obj defaultlib obj2 Step 3 Compile the main program and link against the import libraries for obj3 dll and obj4 dll pgf95 Mdll prog2 f 95 O prog2 defaultlib obj2 defaultlib obj3 Step 4 Execute prog to ensure that the DLLs were created properly prog2 func_2a calling a routine in obj3 dll func _3b func _3a calling a routine in obj2 dll func_2b 8 2 Using LIB3F The PGI Fortran compilers include complete support for the de facto standard LIB3F library routines on both Linux and Windows operating systems See the PGI Fortran Reference manual for a complete list of available routines in the PGI implementation of LIB3F 8 3 LAPACK the BLAS and FFTs Pre compiled versions of the public domain LAPACK and BLAS libraries are included with the PGI compilers on Windows systems in the files PGI lt target gt lib lapack a and PGI lt target gt lib blas a respectively where lt target gt is replaced with the ap
17. global h S FC S FFLAGS c SRC main f utils o SRC utils f SRC global h SRC utils h FC S FFLAGS c SRC utils f utils il SRC utils f SRC global h SRC utils h FC S FFLAGS Mextract 15 o utils il parser o SRC parser f SRC global h utils il FC S FFLAGS Minline utils il c SRC parser f alloc o SRC alloc f SRC global h utils il FC S FFLAGS Minline utils il c SRC alloc f myprog main o utils o parser o alloc o FC o myprog main o utils o parser o alloc o 5 3 Error Detection during Inlining To request inlining information from the compiler when you invoke the inliner specify the Minfo inline option For example pgf95 Minline mylib il Minfo inline myext f 5 4 Examples Assume the program dhry consists of a single source file dhry f The following command line builds an executable file for dhry in which proc7 is inlined wherever it is called pgf95 dhry f Minline proc7 The following command lines build an executable file for dhry in which proc7 plus any functions of approximately 10 or fewer statements are inlined one level only Note that the specified functions are inlined only if they are previously placed in the inline library temp il during the extract phase 100 Function Inlining pgf95 dhry f Mextract o temp il pgf95 dhry f Minline 10 Proc7 temp il Assume the program fibo f contains a single function fibo that call
18. in the text of this manual we show command line options using a dash instead of a hyphen for example Mlist In addition the pgCC command recognizes a group of characters preceded by a plus sign as command line options The order of options and the filename is not fixed That is you can place options before and after the filename argument on the command line However the placement of some options is significant for example the 1 option 16 Getting Started with the Command Line Compilers Note If two or more options contradict each other the last one in the command line takes precedence path is the pathname to the directory containing the file named by filename If you do not specify path for a filename the compiler uses the current directory You must specify path separately for each filename not in the current directory filename is the name of a source file assembly language file object file or library to be processed by the compilation system You can specify more than one path filename 2 2 2 Command line Options The command line options control various aspects of the compilation process For a complete alphabetical listing and a description of all the command line options refer to Chapter 4 Command Line Options 2 2 3 Fortran Directives Fortran directives inserted in program source code allow you to alter the effects of certain command line options and control various aspects of the compilation pr
19. loop count less than or equal to m a supplied constant If this value is not supplied the m count is set to 4 Du instructs the compiler to unroll u times a loop that is not completely unrolled or has a non constant loop count If u is not supplied the unroller computes the number of times a candidate loop is unrolled To set this option in PVF use the Fortran Optimization Loop Unroll Count property instructs the compiler not to unroll loops M no vect option option disable enable the code vectorizer where option is one of the Command Line Options following altcode Instructs the vectorizer to generate alternate code altcode for vectorized loops when appropriate For each vectorized loop the compiler decides whether to generate altcode and what type or types to generate which may be any or all of altcode without iteration peeling altcode with non temporal stores and other data cache optimizations and altcode based on array alignments calculated dynamically at runtime The compiler also determines suitable loop count and array alignment conditions for executing the alcode This option is enabled by default 79 noaltcode assoc noassoc cachesize n no sizelimit smallvect n sse This disables alternate code generation for vectorized loops Instructs the vectorizer to enable certain associativity conversions that can change the results of a computation due to roundoff error A typi
20. multiple processors will be used to execute loops which the auto parallelizer determines to be parallelizable The noconcur directive disables these transformations This directive affects the compiler only when Mconcur is enabled on the command line depchk nodepchk This directive alters the effects of the Mdepchk command line option When potential data dependencies exist the compiler by default assumes that there is a data dependence that in turn may inhibit certain optimizations or vectorizations nodepchk directs the compiler to ignore unknown data dependencies eqvchk noeqvchk When examining data dependencies noeqvchk directs the compiler to ignore any dependencies between variables appearing in EQUIVALENCE statements Optimization Directives 125 invarif noinvarif There is no command line option corresponding to this directive Normally the compiler removes certain invariant if constructs from within a loop and places them outside of the loop The directive noinvarif directs the compiler to not move such constructs The directive invarif toggles a previous noinvarif ivdep The ivdep directive is equivalent to the directive nodepchk opt The syntax of this directive is cpgi lt scope gt opt lt level gt where the optional lt scope gt is r or g and lt level gt is an integer constant representing the optimization level to be used when compiling a subprogram routine scope or all subprograms in a file
21. omp Set_AYNAMIC ccccceseeeteeeseeeeees 118 Fake eed cherie dese egen xii omp set Joch 119 omp sei nestied 119 V omp set mum Weade 118 H Mecher 30 79 OMP_teSt_lOCK eent 119 SSE instructions st vess eh 80 omp upset Joch 119 Optimiza om eese eenia eri eE a Seeria 121 w C C pragmas En 47 Win32 Calling Conventions eler Une DEE 79 STDCALL 147 Fortran directives ccccccceessessseeeeeees CG KS Re lee Fortran directives SCOPE eeen 128 FUNCTION inlining 2 00 eee eeeeeeeeeeeeeeeeeeeteee 24 97 global optimization ee eeeeeeeeeees 24 27 inline Wbrartes ere 98 Inter Procedural Anahvsie AA 24 IRA EE 24 local optimization ee eee eeteeeeeeeeeteneees 23 loop optimization 24 JOOP unrolling 0 eeeeeeeseeeeeneeeeeeeeeeneees 24 29 OOPS ee lg accra lest SEET OO oi eeh eege d EE eege dere E E A E oud cust A E See SE COS erates level tee ees estas parallelization EE prefetching profile feedback PFO ceseeeeeeeenees 46 Profile Feedback Opgimtzatton 24 vechortzation 24 30 Index 224 Index
22. size number levels number 70 instructs the inliner to inline all eligible functions except func a function in the source text Multiple functions can be listed comma separated instructs the inliner to inline the function func The func name should be a non numeric string that does not contain a period You can also use a name prefix followed by the function name If name is specified what follows is always the name of a function instructs the inliner to inline the functions within the library file filename ext The compiler assumes that a filename ext option containing a period is a library file Create the library file using the Mextract option You can also use a lib prefix followed by the library name If lib is specified no period is necessary in the library name Functions from the specified library are inlined If no library is specified functions are extracted from a temporary library created during an extract prepass instructs the inliner to inline functions with number or fewer statements You can also use a size prefix followed by a number If size is specified what follows is always taken as a number instructs the inliner to perform number levels of inlining The default number is 1 Command Line Options If you specify both func and number the compiler inlines functions that match the function name or have number or fewer statements For examples of inlining functions see Function Inlining
23. 2 1 0 maps CPUs 3 2 1 and 0 to threads 0 1 2 and 3 respectively MP_SPIN When a thread executing in a parallel region enters a barrier it spins on a semaphore MP_SPIN can be used to specify the number of times it checks the semaphore before calling sched_yield on linux or _sleep on Windows These calls cause the thread to be re scheduled allowing other processes to run The default values are 100 Linux and 10000 Windows MP_WARN By default a warning will be printed to stderr if you execute an OpenMP or auto parallelized program with NCPUS or OMP_NUM_THREADS set to a value larger than the number of physical processors in the system For example if you produce a parallelized executable a out and execute as follows on a system with only one processor 138 Libraries and Environment Variables d i setenv NCPUS 2 a out Warning OMP_ NUM THREADS or NCPUS 2 greater than available cpus 1 FORTRAN STOP Setting MP_WARN to no will eliminate these warning messages NCPUS The NCPUS environment variable can be used to set the number of processes or threads used in parallel regions The default is to use only one process or thread serial mode If both OMP_NUM_THREADS and NCPUS are set the value of OMP_NUM_THREADS takes precedence Warning setting NCPUS to a value larger than the number of physical processors or cores in your system can cause parallel programs to run very slowly NCPUS_MAX The NCPUS_MAX environm
24. Computes paral para2 para3 etext align 4 Long EN1 sum_3 0xc8000000 align 16 globl sum_3 sum_3 pushl ebp movl esp Sep subl 8 esp ENT fildl 8 ebp fadds 12 ebp faddl 16 ebp fstps 4 ebp flds 4 ebp leave ret type sum_3 function Size sum_3 sum_3 Run time Environment 157 A 2 Win64 Programming Model This section defines compiler and assembly language conventions for the use of certain aspects of an x64 processor running a Win64 operating system These standards must be followed to guarantee that compilers application programs and operating systems written by different people and organizations will work together The conventions supported by the PGCC ANSI C compiler implement the application binary interface ABI as defined in the AMD64 Software Conventions document A 2 1 Function Calling Sequence This section describes the standard function calling sequence including the stack frame register usage and parameter passing Register Usage Conventions The following table defines the standard for register allocation The 64 bit AMD64 Architecture AMD64 provides a number of registers All the general purpose registers XMM registers and x87 registers are global to all procedures in a running program 158 Run time Environment Table A 7 Register Allocation Type Name Purpose General Prax return value register Yorbx callee saved D
25. GC26 4119 OpenMP Application Program Interface Version 2 5 May 2005 OpenMP Architecture Review Board 1997 2005 Preface Chapter 1 Getting Started with PVF This section provides an overview of how to use PGI Visual Fortran within the Microsoft Visual Studio 2005 IDE For information on generic use of the Visual Studio 2005 IDE see the Visual Studio online help or http msdn microsoft com library default asp url library en us dnanchotr html vs2005anchor asp PVF runs within Visual Studio 2005 so to invoke PVF one must invoke Visual Studio If other languages such as Visual C or Visual Basic are installed they will be available in the same instance of Visual Studio as PVF To invoke PVF go to the Windows Start menu and select Start All Programs PGI Visual Fortran PGI Visual Fortran Visual Studio will start Alternatively Visual Studio 2005 may be invoked using Start All Programs Microsoft Visual Studio 2005 Microsoft Visual Studio 2005 PVF projects and settings will be available as with any other language The first time Visual Studio is started it may display a list of default settings from which to choose select General Development Settings If Visual Studio was installed prior to the PVF install it will start as usual after PVF is installed except PVF projects and settings will be available 1 1 Creating a PVF Project Once Visual Studio 2005 is running it can be used to create a PGI Visual Fortran project PVF s
26. INTEGER 4 Mipa lt option gt lt option gt Pass options to the interprocedural analyzer Note Mipa implies O2 Command Line Options and the minimum optimization level that can be specified in combination with Mipa is O2 For example if you specify Mipa O1 on the command line the optimization level will automatically be elevated to O2 by the compiler driver It is typical and recommended to use Mipa fast Many of the following sub options can be prefaced with no which reverses or disables the effect of the sub option if it s included in an aggregate sub option like Mipa fast The choices of option are no align recognize when targets of a pointer dummy are aligned default is noalign no arg remove arguments replaced by const ptr default is noarg no cg generate call graph information for viewing using the pgicg command line utility default is nocg no const perform interprocedural constant propagation default is const 75 76 except lt func gt no f90ptr fast force no globals inline n ipofile no keepobj no libc no libinline no libopt no localarg main lt func gt no ptr no pure used with inline to specify functions which should not be inlined default is to inline all eligible functions according to internally defined heuristics F90 F95 pointer disambiguation across calls default is nof90ptr choose IPA options general
27. Ktrap inv divz ovf To set this option in PVF use the Fortran Floating Point Options Floating Point Exception Handling property Default The default is Knoieee L Specifies a directory to search for libraries Use L to add directories to the search path for library files Multiple L options are valid However the position of multiple L options is important relative to l options supplied Syntax Ldirectory Where directory is the name of the library directory Default Search the standard library directory Usage In the following example the library directory is lib and the linker links in the standard libraries required by PGF95 from lib pgf95 L lib myprog f In the following example the library directory lib is searched for the library file libx a and both the directories lib and libz are searched for liby a pgf95 L lib 1x L libz ly myprog f l lt library gt Loads a library The linker searches lt library gt in addition to the standard libraries Libraries specified with Jare searched in order of appearance and before the standard libraries Syntax llibrary Where library is the name of the library to search The compiler prepends the characters lib to the library name and adds the a extension following the library name Usage In the following example if the standard library directory is lib the linker loads the library lib libmylib a in addition to the standard libraries C
28. Loop unrolled 7 times completely unrolled loop 18 Generating vector sse code for inner loop Generated 3 prefetch instructions for this loop Note the informational message indicating that the loop has been vectorized and SSE instructions have been generated The second part of the informational message notes that prefetch instructions have been generated for 3 loads to minimize latency of transfers of data from main memory Executing again you should see results similar to the following bin time a Out 1 000000 771 000 3618 00 6498 00 9999 0 3 55user 0 00system 0 03 56elapsed 99 CPU The result is a speed up of 45 over the equivalent scalar i e non SSE version of the program Speed up realized by a given loop or program can vary widely based on a number of factors Performance improvement using vector SSE or SSE2 instructions is most effective when the vectors of data are resident in the data cache e If data is aligned properly performance will be better in general than when using vector SSE operations on unaligned data e If the compiler can guarantee that data is aligned properly even more efficient sequences of SSE instructions can be generated SSE2 vector instructions can operate on 4 single precision elements concurrently but only 2 double precision elements As a result the efficiency of loops that operate on single precision data can be higher Note Compiling with Mvect sse can result in numer
29. Resource Compiler to produce binary res files A res file is then directly passed to the linker which incorporates the resources into the output file See the PVF sample project menu_dialog for details on how resources are used within a windows application Note The complete Visual C Resource Editor is not available in PVF Although you can edit files like icons ico and bitmaps bmp directly the rc file is not updated automatically by the environment You must either install Visual C in which case the resource editor is fully functional or you must edit rc files using the source code text editor 1 17 5 2 Building Windows Applications from the Command Line Windows applications can also be built using a command line version of pgf95 To enable this feature add the winapp option to the compiler driver command line when linking the application This option causes the linker to include the correct libraries and object files needed to support a Windows Application However it does not add any additional system libraries to the link line Add any required system libraries by adding the option defaultlib lt library name gt to the link command line for each library lt library name gt can be any of the following advapi32 comdlg32 gdi372 kernel 32 shell32 user32 winver or wsock32 14 Getting Started with PVF Chapter 2 Getting Started with the Command Line Compilers This chapter describes how to use the PGI compiler
30. To translate and link a Fortran language program the pgf77 and pgf95 commands do the following e Preprocess the source text file Check the syntax of the source text Generate an assembly language file e Pass control to the subsequent assembly and linking steps For example if you enter the following simple Fortran program in the file hello f 15 print hello end You can compile it from a shell prompt using the default pgf95 driver options PGI pgf95 hello f Linking PGIS By default the executable output is placed in the file a out or on Windows platforms a filename based on the name of the first source or object file on the command line Use the o option to specify an output file name To place the executable output in the file hello PGI pgf95 o hello f Linking PGIS To execute the resulting program simply type the filename at the command prompt and press the Return or Enter key on your keyboard PGIS hello hello PGIS 2 2 1 Command line Syntax The command line syntax using pgf95 as an example is pgf95 options path filename Where options is one or more command line options all of which are described in detail in Chapter 4 Command Line Options Case is significant for options and their arguments The compiler drivers recognize characters preceded by a hyphen as command line options For example the Mlist option specifies that the compiler creates a listing file
31. and 64 bit addressing capabilities that are utilized by the PGI compilers and tools when running on a 64 bit operating system The prefetch SSE1 SSE2 and SSE3 processor features further distinguish the various processors Where such distinctions are important with respect to a given compiler option or feature it is explicitly noted in this manual Note that the default for performing scalar floating point arithmetic is to use SSE instructions on targets that support SSE1 and SSE2 See section 2 3 1 Scalar SSE Code Generation for a detailed discussion of this topic Preface xiii Related Publications The following documents contain additional information related to the x86 and x64 architectures and the compilers and tools available from The Portland Group xiv PGI Fortran Reference manual describes the FORTRAN 77 Fortran 90 95 and HPF statements data types input output format specifiers and additional reference material related to use of the PGI Fortran compilers System V Application Binary Interface Processor Supplement by AT amp T UNIX System Laboratories Inc Prentice Hall Inc System V Application Binary Interface X86 64 Architecture Processor Supplement http www x86 64 org abi pdf Fortran 95 Handbook Complete ISO ANSI Reference Adams et al The MIT Press Cambridge Mass 1997 Programming in VAX Fortran Version 4 0 Digital Equipment Corporation September 1984 IBM VS Fortran IBM Corporation Rev
32. and use them to build the main program In the following source files object2 f95 makes calls to routines defined in object3 f95 and vice versa This situation of mutual imports requires two steps to build each DLL object2 95 subroutine func_2a external func_3b DECS ATTRIBUTES DLLEXPORT func Za DECS ATTRIBUTES DLLIMPORT func _3b Libraries and Environment Variables 135 print func_ 2a calling a routine in obj3 d11 call func_3b end subroutine subroutine func_2b DECS ATTRIBUTES DLLEXPORT print func_2b end subroutine object3 95 subroutine func_3a external func_2b IDECS ATTRIBUTES DLLEXPORT IDECS ATTRIBUTES DLLIMPORT print func 3a call func_2b end subroutine subroutine func_3b DECS ATTRIBUTES DLLEXPORT print func_3b end subroutine prog2 f95 program prog2 external func_2a external func_3a DECS ATTRIBUTES DLLIMPORT DECS ATTRIBUTES DLLIMPORT call func_2a call func_3a end program func_2b func _3a func_2b func_3b func_2a func_3a calling a routine in obj2 dl1 Step 1 To make obj2 dll and obj3 dll first compile the source and create an import library for each DLL that will be built The PGI drivers call the Microsoft lib tool to create import libraries The lib tool will only create an import library if a module definition def file is provided A def file contains symbols to export In this example the symbols to be exported are already marked as such
33. are optimized using unrolling SSE instructions vectorization parallelization interprocedural optimizations and various miscellaneous optimizations You can also see where and whether functions are inlined The Mneginfo option can be used to display informational messages listing why certain optimizations are inhibited The dryrun option can be useful as a diagnostic tool if you need to see the steps used by the compiler driver to pre process compile assemble and link in the presence of a given set of command line inputs When you specify the dryrun option these steps will be printed to stdout but will not actually be performed For example this allows inspection of the default and user specified libraries that are searched during the link phase and the order in which they are searched by the linker The remainder of this chapter describes the O options the loop unroller option Munroll the vectorizer option Mvect the auto parallelization option Mconcur and the inter procedural analysis optimization Mipa and the profile feedback instrumentation Mpfi and optimization Mpfo options Usually you should be able to get very near optimal compiled performance using some combination of these switches The following overview will help if you are just getting started with one of the PGI compilers or wish to experiment with individual optimizations Complete specifications of each of these options are listed in Chapter 4 Co
34. argument that is used as a subroutine W362 Argument has a different type than dummy argument The type of the actual argument is different than the type of the corresponding dummy argument W363 Dummy argument is a POINTER but actual argument is not The dummy argument is a pointer so the actual argument must be also W364 Array or array expression passed to scalar dummy argument The actual argument is an array but the dummy argument is a scalar variable W365 Scalar or scalar expression passed to array dummy argument The actual argument is a scalar variable but the dummy argument is an array F366 Internal error interprocedural analysis fails An internal error occurred during interprocedural analysis please report this to the compiler maintenance group If user errors were reported when collecting IPA information or during IPA analysis correcting them may avoid this error I367 Array bounds cannot be matched to formal argument Passing a nonsequential array to a sequential dummy argument may require copying the array to sequential storage The most common cause is passing an ALLOCATABLE array or array expression to a dummy argument that is declared with explicit bounds Declaring the dummy argument as assumed shape with bounds will remove this warning 206 Messages W368 Array valued expression passed to scalar dummy argument The actual argument is an array valued expression but the dummy argume
35. at label 2 prevents k from being recognized as an induction variable If the conditional statement at label 2 is removed k would be an induction variable whose value varies linearly with j and the loop could be parallelized 3 6 2 4 Scalar Last Values During parallelization scalars within loops often need to be privatized that is each execution thread will have its own independent copy of the scalar Problems can arise if a privatized scalar is accessed outside the loop For example consider the following loop do I 1 if x ts endif enddo iN I gt 5 0 then I Vist The value of t may not be computed on the last iteration of the loop Normally if a scalar is assigned within a loop and used following the loop the PGI compilers save the last value of the scalar However if the loop is parallelized and the scalar is not assigned on every iteration it may be difficult without resorting to costly critical sections to determine on what iteration t is last assigned Analysis allows the compiler to determine that a scalar is assigned on each iteration and hence that the loop is safe to parallelize if the scalar is used later For example do I 1 N if x I gt 0 0 then f 2 0 else E Optimization amp Parallelization 39 E REN endif enddo Ves t where t is assigned on every iteration of the loop However there are cases where a scalar may be privatizable but if it is used after the loop it is unsafe to
36. based systems running a 64 bit operating system because the application binary interface ABI for those systems is still evolving See http www x86 64 org abi pdf for the latest version of this ABI 9 1 Fortran Data Types 9 1 1 Fortran Scalars A scalar data type holds a single value such as the integer value 42 or the real value 112 6 The next table lists scalar data types their size format and range Table 9 2 Real Data Type Ranges shows the range and approximate precision for Fortran real data types Table 9 3 Scalar Type Alignment shows the alignment for different scalar data types The alignments apply to all scalars whether they are independent or contained in an array a structure or a union 141 Table 9 1 Representation of Fortran Data Types Fortran Data Type Format Range INTEGER 2 s complement integer 231 to 231 1 INTEGER 2 2 s complement integer 32768 to 32767 INTEGER 4 same as INTEGER INTEGER 8 same as INTEGER 263 to 263 1 LOGICAL same as INTEGER true or false LOGICAL 1 8 bit value true or false LOGICAL 2 16 bit value true or false LOGICAL 4 same as INTEGER true or false LOGICAL 8 same as INTEGER true or false BYTE 2 s complement 128 to 127 REAL Single precision floating point 10 37 to 1038 1 REAL 4 Single precision floating point 10 37 to 1038 1 REAL 8 Double precision floating point 10 307 to 10308 1 DOUBLE PRE
37. box 1 17 Compatibility PGI Visual Fortran provides features that are compatible with those supported by older Windows Fortran products such as Compaq Visual Fortran These include Win32 API Support Portability Support Unix Linux Graphical User Interface Support This section describes how to use each of these features 10 Getting Started with PVF 1 17 1 Win32 API Support The Microsoft Windows operating system interface the system call and library interface is known collectively as the Win32 API This is true for both the 32 bit and 64 bit versions of Windows there is no Win64 API for 64 bit Windows The only difference on 64 bit systems is that pointers are 64 bits rather than the 32 bit pointers found on 32 bit Windows PGI Visual Fortran provides access to the Win32 API using Fortran modules See the sections entitled Fortran Module Library Interfaces and Data Types for more information on the use of these interfaces Source code for the modules is located in C Program Files PGI win6 4 lt release number gt src For details on specific Win32 API routines see the online Microsoft Platform SDK documentation or visit the Microsoft MSDN website msdn microsoft com library default asp url code list win32api asp The modules and their corresponding Win32 libraries are shown in the following table Table 1 2 PVF Win32 API Module Mappings C Win32 API Lib C Header File
38. by the driver from your command line input and the default values Default The compiler does not display individual phase invocations Usage The following command line requests verbose invocation information pgf95 prog f Cross reference Minfo V v HHH Use the option to display the invocations of the compiler assembler and linker but do not execute them These invocations are command lines created by the compiler driver from the PGIRC files and the command line options Default The compiler does not display individual phase invocations Usage The following command line requests verbose invocation information pgf95 myprog f Cross reference Minfo V dryrun 52 Command Line Options byteswapio Use the byteswapio option to swap the byte order of data in unformatted Fortran data files on input output When this option is used the order of bytes is swapped in both the data and record control words the latter occurs in unformatted sequential files Specifically this option can be used to convert big endian format data files produced by most RISC workstations and high end servers to the little endian format used on x86 or x64 systems on the fly during file reads writes This option assumes that the record layouts of unformatted sequential access and direct access files are the same on the systems Also the assumption is that the IEEE representation is used for floating point numbers I
39. byte in a 4 byte word The following is an example of the pseudo code for the above call using STDCALL conventions call _work 20 val E tsval a saddr b tval n Note that in this case there are still 20 bytes in the argument list However rather than 5 4 byte quantities as in the Default convention there are 3 4 byte quantities and 1 8 byte quantity the double precision value of a 147 148 Inter language Calling Appendix A Run time Environment This appendix describes the programming model supported for compiler code generation including register conventions and calling conventions for x86 and x64 processor based systems running Windows operating systems Al Win32 Programming Model This section defines compiler and assembly language conventions for the use of certain aspects of an x86 processor running a Win32 operating system These standards must be followed to guarantee that compilers application programs and operating systems written by different people and organizations will work together The conventions supported by the PGCC ANSI C compiler implement the application binary interface ABI as defined in the System V Application Binary Interface Intel Processor Supplement and the System V Application Binary Interface listed in the Related Publications section in the Preface A 1 1 Function Calling Sequence This section describes the standard function calling sequence including the stack frame regis
40. core processor based systems Mcray option option Force Cray Fortran CF77 compatibility with respect to the listed options Mdepchk 74 Possible values of option include ointer for purposes of optimization it is assumed that P purp P pointer based variables do not overlay the storage of any other variable instructs the compiler to assume unresolved data dependencies actually conflict Command Line Options Mnodepchk instructs the compiler to assume potential data dependencies do not conflict However if data dependencies exist this option can produce incorrect code Mfprelaxed option Mnofprelaxed Mi4 instructs the compiler to use relaxed precision in the calculation of some intrinsic functions Can result in improved performance at the expense of numerical accuracy To set this option in PVF use the Fortran Floating Point Options Floating Point Consistency property The possible values for option are div Perform divide using relaxed precision sqrt Perform square root with relaxed precision rsqrt Perform reciprocal square root 1 sqrt using relaxed precision With no options Mfprelaxed will choose generate relaxed precision code for those operations that generate a significant performance improvement depending on the target processor default instructs the compiler not to use relaxed precision in the calculation of intrinsic functions the compiler treats INTEGER variables as
41. directive uses the following syntax SOMP BARRIER There may be occasions in a parallel region when it is necessary that all threads complete work to that point before any thread is allowed to continue The BARRIER directive synchronizes all threads at such a point in a program Multiple barrier points are allowed within a parallel region The BARRIER directive must either be executed by all threads executing the parallel region or by none of them 6 9 DOACROSS The C6DOACROSS directive is not part of the OpenMP standard but is supported for compatibility with programs parallelized using legacy SGI style directives Syntax 112 OpenMP Directives for Fortran CSDOACROSS Clauses lt Fortran DO loop to be executed in parallel gt Clauses PRIVATE LOCAL list SHARED SHARE list MP_SCHEDTYPE SIMPLE INTERLEAVE CHUNK lt integer_expression gt IF logical _expression The C DOACROSS directive has the effect of a combined parallel region and parallel DO loop applied to the loop immediately following the directive It is very similar to the OpenMP PARALLEL DO directive but provides for backward compatibility with codes parallelized for SGI systems prior to the OpenMP standardization effort The CSDOACROSS directive must not appear within a parallel region It is a shorthand notation that tells the compiler to parallelize the loop to which it applies even though that loop is not contained within a
42. extract phase is performed the compile and link phases are not performed The output of an extract pass is a library of functions available for inlining It is placed in the inline library file specified on the command line with the o filename specification If the library file exists new information is appended to it If the file does not exist it is created You can use the Minline option with the Mextract option In this case the extracted library of functions can have other functions inlined into the library Using both options enables you to obtain more than one level of inlining In this situation if you do not specify a library with the Minline option the inline process consists of two extract passes The first pass is a hidden pass implied by the Minline option during which the compiler extracts functions and places them into a temporary library The second pass uses the results of the first pass but puts its results into the library that you specify with the o option 5 2 1 Working with Inline Libraries An inline library is implemented as a directory with each inline function in the library stored as a file using an encoded form of the inlinable function A special file named TOC in the inline library directory serves as a table of contents for the inline library This is a printable ASCII file which can be examined to find out information about the library contents such as names and sizes of functions the source f
43. find entry symbol _start Mnostdlib instructs the linker not to link in the standard libraries libpgftnrtl a libm a libc a and libpgc a in the library directory lib within the standard directory You can link in your own library with the l option or specify a library directory with the L option Default For arguments that you do not specify the default environment option depends on your configuration Cross reference D I L l U M lt pegflag gt Inlining Controls This section describes the M lt pgflag gt options that control function inlining Syntax Mext ract option option Extracts functions from the file indicated on the command line and creates or appends to the specified extract directory where option can be any of Command Line Options 69 name func size number lib filename ext instructs the extractor to extract function func from the file instructs the extractor to extract functions with number or fewer statements from the file Use directory filename ext as the extract directory required in order to save and re use inline libraries If you specify both name and size the compiler extracts functions that match func or that have number or fewer statements For examples of extracting functions see Function Inlining Min1line option option This passes options to the function inliner where option can be any of except func name func lib filename ext
44. for various compilation steps Usage In the following example pgf95 prints the execution times for the various compilation steps pgf95 time myprog f Cross reference 92 Command Line Options tp Set the target architecture By default the PGI compilers produce code specifically targeted to the type of processor on which the compilation is performed In particular the default is to use all supported instructions wherever possible when compiling on a given system As a result executables created on a given system may not be useable on previous generation systems for example executables created on a Pentium 4 may fail to execute on a Pentium III or Pentium II Processor specific optimizations can be specified or limited explicitly by using the tp option In this way it is possible to create executables that are usable on previous generation systems With the exception of k8 64 k8 64e p7 64 and x64 any of these sub options are valid on any x86 or x64 processor based system The k8 64 k8 64e p7 64 and x64 options are valid only on x64 processor based systems The tp x64 option is used to generate unified binary object and executable files The tp k8 64 and tp k8 64e options result in generation of code supported on and optimized for AMD x64 processors while the tp p7 64 option results in generation of code that is supported on and optimized for Intel x64 processors Performance of k8 64 or k8 64e code executed
45. g generate DWARF2 format Code Generation debug information dwarf3 when used with g generate DWARF3 format Code Generation debug information extend the compiler accepts 132 column source code Fortran Language otherwise it accepts 72 column code pgf77 pgf95 and pghpf only extract invokes the function extractor Inlining fixed the compiler assumes F77 style fixed format Fortran Language source code pgf95 and pghpf only no flushz do don t set SSE flush to zero mode Code Generation no fprelaxed option Perform certain floating point intrinsic functions using relaxed precision Optimization free the compiler assumes F90 style free format Fortran Language source code pgf95 and pghpf only func32 the compiler aligns all functions to 32 byte Code Generation boundaries gccbug s match behavior of certain gcc bugs Miscellaneous noi4 determines how the compiler treats INTEGER Optimization variables 62 Command Line Options around Fortran I O calls pgflag Description Category info prints informational messages regarding optimi Miscellaneous zation and code generation to standard output as compilation proceeds inform specifies the minimum level of error severity that Miscellaneous the compiler displays inline invokes the function inliner Inlining no ipa invokes inter procedural analysis and optimiza Optimization tion no iomutex determines whethe
46. global scope The opt directive overrides the value specified by the command line option On Istval nolstval There is no command line option corresponding to this directive The compiler determines whether the last values for loop iteration control variables and promoted scalars need to be computed In certain cases the compiler must assume that the last values of these variables are needed and therefore computes their last values The directive nolstval directs the compiler not to compute the last values for those cases safe_lastval During parallelization scalars within loops need to be privatized Problems are possible if a scalar is accessed outside the loop For example do i 1 N if x i gt 5 0 t x i enddo ME tS le creates a problem since the value of t may not be computed on the last iteration of the loop If a scalar assigned within a loop is used outside the loop we normally save the last value of the scalar Essentially the value of the scalar on the last iteration is saved in this case wheni N 126 Optimization Directives If the loop is parallelized and the scalar is not assigned on every iteration it may be difficult to determine on what iteration t is last assigned without resorting to costly critical sections Analysis allows the compiler to determine if a scalar is assigned on every iteration thus the loop is safe to parallelize if the scalar is used later An example loop is d t ser RN
47. ifndef directive was not followed by an identifier 253 Too many actual parameters to The number of actual arguments to the indicated macro exceeded the maximum allowed currently 31 S254 Too many formal parameters to 198 Messages The number of formal arguments to the indicated macro exceeded the maximum allowed currently 31 F255 Too much pushback The preprocessor ran out of space while processing a macro expansion The macro may be recursive W256 Undefined directive The identifier following a was not a directive name S257 EOF in include directive End of file was encountered while processing a include directive 258 Unmatched elif A elif directive was encountered with no preceding if or elif directive S259 Unmatched else A else directive was encountered with no preceding if or elif directive 260 Unmatched endif A endif directive was encountered with no preceding if ifdef or ifndef directive S261 Include files nested too deeply The nesting depth of include directives exceeded the maximum currently 20 S262 Unterminated macro definition for A newline was encountered in the formal parameter list for the indicated macro 263 Unterminated string or character constant A newline with no preceding backslash was found in a quoted string I264 Possible nested comment The characters were found within a comment S265 lt reserved message number gt S266 lt reser
48. instruction w use the AMD specific prefetchw instruction Disables generation of prefetch instructions the compiler promotes REAL variables and constants to DOUBLE PRECISION variables and constants respectively DOUBLE PRECISION elements are 8 bytes in length the compiler does not promote REAL variables and constants to DOUBLE PRECISION REAL variables will be single precision 4 bytes in length the compiler treats the intrinsics CMPLX and REAL as DCMPLX and DBLE respectively Command Line Options Mnor8gintrinsics Mscalarsse Mnoscalarsse Msmart Mnosmart the compiler does not promote the intrinsics CMPLX and REAL to DCMPLX and DBLE respectively Use SSE SSE2 instructions to perform scalar floating point arithmetic this option is valid only on tp p7 k8 32 k8 64 targets Do not use SSE SSE2 instructions to perform scalar floating point arithmetic use x87 instructions instead this option is not valid in combination with the tp k8 64 option instructs the compiler driver to invoke an AMD64 specific post pass assembly optimization utility instructs the compiler not to invoke an AMD64 specific post pass assembly optimization utility Munro11 option option invokes the loop unroller This also sets the optimization level to 2 if the Mnounroll level is set to less than 2 The option is one of the following c m instructs the compiler to completely unroll loops with a constant
49. is zero 194 Messages 207 Integer constant expected in edit descriptor S208 Period expected in edit descriptor 209 Illegal edit descriptor 210 Exponent width not used in the Ew dEe or Gw dEe edit descriptors 211 Internal I O not allowed in this I O statement 212 Illegal NAMELIST I O Namelist I O cannot be performed with internal unformatted formatted and list directed I O Also I O lists must not be present 213 is not a NAMELIST group name 214 Input item is not a variable reference 215 Assumed sized array name cannot be used as an I O item or specifier An assumed sized array was used as an item to be read or written or as an I O specifier Ge FMT array name In these contexts the size of the array must be known 216 STRUCTURE UNION cannot be used as an I O item 217 ENCODE DECODE buffer must be a variable array or array element Messages 195 S218 Statement labeled S219 lt reserved message number gt S220 Redefining predefined macro S221 elif after else A preprocessor elif directive was found after a else directive only endif is allowed in this context S222 else after else A preprocessor else directive was found after a else directive only endif is allowed in this context 223 if directives too deeply nested Preprocessor if directive nesting exceeded the maximum allowed currently 10 224 Actual parameters too long for The total length of the parame
50. libraries to the link line pgf90libs Append PGF90 PGF95 runtime libraries to the link line Q Selects variations for compiler steps r Creates a relocatable object file r4 and r8 Interpret DOUBLE PRECISION variables as REAL r4 and r8 Interpret REAL variables as DOUBLE PRECISION rc file Specifies the name of the driver s startup file S Stops after the compiling phase and saves the assembly language code in filename s s Strips the symbol table information from the object file show Display driver s configuration parameters after startup silent Do not print warning messages time Print execution times for the various compilation steps U lt symbol gt Undefine a preprocessor macro Command Line Options 51 Option Description u lt symbol gt Initializes the symbol table with lt symbol gt which is undefined for the linker An undefined symbol triggers loading of the first member of an archive library V release_number Displays the version messages and other information or allows invo cation of a version of the compiler other than the default V Displays the compiler assembler and linker phase invocations W Passes arguments to a specific phase W Do not print warning messages 4 1 Generic PGI Compiler Options Use the option to display the invocations of the compiler assembler and linker These invocations are command lines created
51. newly created project files and folders 1 2 Migrating an Existing Application to PVF An existing non PVF Fortran application or library project can be migrated to PVF Create an Empty Project then right click on the project node in the Solution Explorer to bring up the project context menu From this menu select Add Existing Item and use the Add Existing Item dialog to navigate to the location of the source files to be added to the project Select the desired source files and click OK to add them to the project PVF will attempt to determine which files are include files as opposed to source files that is which files are only included in other files and should not be built If PVF s decision is incorrect or if the status of a file changes the file s type can be set manually as described in Setting File Properties in PVF below Include files are generally located in the Include Files folder in the Solution Explorer and source files in the Source Files folder Icons are used to distinguish include files fixed format source files and free format source files 1 3 PVF Solution Explorer PVF uses the standard Visual Studio Solution Explorer to organize files in PVF projects Visual Studio uses the term project to refer to a set of files build rules and so on that creates an output like an executable DLL or static library Projects are collected into a solution which is composed of one or more projects that are usua
52. of the processors are being time shared with another executing job can also result in inefficient execution As with the vectorizer the Mconcur option can speed up code if it contains well behaved countable loops and or computationally intensive nested loops that operate on arrays However it is possible that some codes will show a decrease in performance on multi processor systems when compiled with Mconcur due to parallelization overheads memory bandwidth limitations in the target system false sharing of cache lines or other architectural or code generation factors For this reason it is recommended that you check carefully whether particular program units or loops show improved performance when compiled using this option If the compiler is not able to successfully auto parallelize your application you should refer to Chapter 6 OpenMP Directives for Fortran to see if insertion of explicit parallelization directives or pragmas and use of the mp compiler option enables the application to run in parallel 3 6 2 Loops That Fail to Parallelize In spite of the sophisticated analysis and transformations performed by the compiler programmers will often note loops that are seemingly parallel but are not parallelized In this subsection well look at some examples of common situations where parallelization does not occur Optimization amp Parallelization 37 3 6 2 1 Innermost Loops As noted earlier in this chapter the PGI compil
53. on Intel x64 processors or of p7 64 code executed on AMD x64 processors can often be significantly less than that obtained with a native binary The tp x64 option results in generation of unified binary object and executable files which are supported on and include optimized code sequences for both AMD and Intel x64 processors To set this option in PVF use the Fortran Optimization Processor Specific Optimization property Following is a list of possible sub options to tp and the processors they are intended to target k8 32 generate 32 bit code for AMD Athlon64 AMD Opteron and compatible processors k8 64 generate 64 bit code for AMD Athlon64 AMD Opteron and compatible processors k8 64e generate 64 bit code for AMD Opteron Revision E AMD Turion and compatible processors p6 generate 32 bit code for Pentium Pro II II and AthlonXP compatible processors p7 generate 32 bit code for Pentium 4 and compatible processors p7 64 generate 64 bit code for Intel P4 Xeon EM64T and compatible processors core2 generate 32 bit code for Intel Core 2 Duo and compatible processors core2 64 generate 64 bit code for Intel Core 2 Duo EM64T and compatible processors piii generate 32 bit code for Pentium II and compatible processors including support for single precision vector code using SSE instructions px generate 32 bit code that is useable on any x86 processor based system Command Line Options 93 x64 generate 64 bit unified b
54. options and the output files that the compilers create when you use these options Table 2 1 Stop after Options Inputs and Outputs z Stop Option after Input Output E prepro Source files must have F extension for Fortran preprocessed file to cessing standard out EN prepro Source files must have F extension this option is not preprocessed file f cessing valid for pgcc or pgCC S compi Source files or preprocessed files assembly language lation file s c assem Source files preprocessed files or assembly language unlinked object file bly files 0 none linking Source files preprocessed files assembly language executable files a out files object files or libraries If you specify multiple input files or do not specify an object filename the compiler uses the input filenames to derive corresponding default output filenames of the following form where filename is the input filename without its extension filename f indicates a preprocessed file if you compiled a Fortran file using the P option Dlename stindicates a listing file from the Mlist option filename o indicates an object file from the c option filename s indicates an assembly language file from the S option Note Unless you specify otherwise the destination directory for any output file is the current working directory If the file exists in the destination directory the compiler overwrit
55. pointers pgf95 and pghpf only Miscellaneous chkstk check the stack for available space upon entry to Miscellaneous and before the start of a parallel region Useful when many private variables are declared concur enable auto concurrentization of loops Multiple Optimization processors or cores will be used to execute paral lelizable loops cpp run the PGI cpp like pre processor without per Miscellaneous forming subsequent compilation steps cray Force Cray Fortran CF77 compatibility pgf77 Optimization pgf95 and pghpf only no daz Do don t treat denormalized numbers as zero Code Generation no dclchk determines whether all program variables must be Fortran Language Command Line Options 61 pgflag Description Category no defaultunit determines how the asterisk character is Fortran Language treated in relation to standard input and standard output regardless of the status of I O units 5 and 6 pgf77 pgf95 and pghpf only no depchk checks for potential data dependencies Optimization no dlines determines whether the compiler treats lines con Fortran Language taining the letter D in column one as executable statements pgf77 pgf95 and pghpf only dollar specifies the character to which the compiler Fortran Language maps the dollar sign code dwarf1 when used with g generate DWARF 1 format Code Generation debug information dwarf2 when used with
56. prefixed with M for example the directive Mbounds is equivalent to bounds and Mopt is equivalent to opt 122 Optimization Directives Table 7 1 Fortran Optimization Directive Summary Directive Function Default Scope altcode noaltcode Do don t generate alternate code for vec altcode Drg torized and parallelized loops assoc noassoc Do don t perform associative transforma assoc Drg tions bounds nobounds Do don t perform array bounds checking nobounds r g cncall nocncall Loops are considered for parallelization nocncall Drg even if they contain calls to user defined subroutines or functions or if their loop counts do not exceed usual thresholds concur noconcur Do don t enable auto concurrentization of concur Drg loops depchk nodepchk Do don t ignore potential data dependen depchk Drg cies eqvchk noeqvchk Do don t check EQUIVALENCE s for data eqvchk Drg dependencies invarif noinvarif Do don t remove invariant if constructs invarif Drg from loops ivdep Ignore potential data dependencies depchk Drg Istval nolstval Do don t compute last values Istval Drg opt Select optimization level N A lg safe_lastval Parallelize when loop contains a scalar not enabled dl used outside of loop unroll nounroll Do don t unroll loops nounroll Drg vector novector Do don t perform vectorizations vector Drg vintr novintr Do don t recogniz
57. processors However the processing cores are on a single chip occupying a single socket on a system motherboard For purposes of PGI software licensing a multi core processor is treated as a single CPU 2 4 1 Running SMP Parallel Programs When you execute an SMP parallel program by default it will use only processor To run on more than one processor set the NCPUS environment variable to the desired number of processors subject to a maximum of 4 for PGI s workstation class products You can set this environment variable by issuing the following command setenv NCPUS lt number gt in a Windows command prompt window Note If you set NCPUS to a number larger than the number of physical processors your program may execute very slowly 20 Getting Started with the Command Line Compilers 2 5 Using the PGI Compilers on Windows 2 5 1 Command Prompt Window The PVF submenu in the Windows Start menu contains an item named PVF Command Prompt This is used to launch a Windows Command Prompt window that has an environment pre initialized for usage of the PGI compilers and tools On x64 systems there are two selections one is tagged x64 to denote that its environment is pre initialized for the 64 bit compilers and tools Getting Started with the Command Line Compilers 21 22 Getting Started with the Command Line Compilers Chapter 3 Optimization amp Parallelization Source code that is readable maintainable and produc
58. propagation The IPA linker reinvokes the compiler on each of the object files to recompile them with interprocedural information This creates three new objects with mangled names filel pap filel exe obj file2 ipa5 filel exe obj file2 ipa5 filel exe obj The system linker is then invoked to link these IPA optimized objects into the final executable Later if one of the three source files is edited the executable can be rebuilt with the same command line pgf95 Mipa fast o filel exe filel f95 file2 95 file3 95 This will work but again has the side effect of compiling each source file and recompiling each object file at link time 3 7 6 Building a Program with IPA Several Steps Just by adding the Mipa command line switch it is possible to use individual pgec commands to compile each source file followed by a command to link the resulting object files into an executable pgf95 Mipa fast c filel f95 pgf95 Mipa fast c file2 f 95 pgf95 Mipa fast c file3 f 95 pgf95 Mipa fast o filel exe filel obj file2 obj file3 obj d i d i dp d Optimization amp Parallelization 43 The pgcc driver invokes the compiler and assembler as required to process each source file and invokes the IPA linker for the final link command If you modify one of the source files the executable can be rebuilt by compiling just that file and then relinking pgf95 c filel f95 pgf95 o filel exe filel obj file2 obj file3 obj When
59. set this option in PVF use the Fortran General Profiling property To enable profiling you must also set the Linker General Profiling property instructs the compiler to allow Fortran subprograms to be called recursively 67 Mref_externals Mnoref_externals Mreentrant Mnoreentrant Fortran subprograms may not be called recursively force references to names appearing in EXTERNAL statements do not force references to names appearing in EXTERNAL statements pgf77 pgf95 and pghpf only instructs the compiler to avoid optimizations that can prevent code from being reentrant instructs the compiler not to avoid optimizations that can prevent code from being reentrant Msecond_underscore instructs the compiler to add a second underscore to the name of a Fortran global symbol if its name already contains an underscore This option is useful for maintaining compatibility with object code compiled using g77 which uses this convention by default Mnosecond_underscore Msignextend Mnosignextend Msafe_lastval Mstride0d Mnostrideod Munix 68 instructs the compiler not to add a second underscore to the name of a Fortran global symbol if its name already contains an underscore instructs the compiler to extend the sign bit that is set as a result of converting an object of one data type to an object of a larger signed data type instructs the compiler not to extend the sign bit that is set as
60. si EEN 86 MONT IP eeens dE 72 221 UU DEE 86 Mpilo senini nnanet erraien 78 SC Ce DEE 78 HMpretetehy s cc c ccczncaseseicecsasbecseasagabsecscasaztee 78 MPpreprocesS sccescceeeseeeseeeeneseeeeneees 85 RO te EE 67 SUE eieiei ee ee ets 78 MYIBiNtriNSICS 2 0 cceceeeeeeeeeessesessseseenees 78 MY CUISIVE E 67 Mreentrant 0 cccccccccceceeeeeeesessseesseseseeees 68 Mref_externals cccceeccsceeeeeeeeseneeees 68 Masate Jastbva 68 SMS AVC get secete cence cd eg 72 MscalarSSe niinen 79 Msecond underecore sss nennnsnnnienneeeeen 68 Msignextend cccceecccesceeeeeseeenereeseeeees 68 Msmart we 79 Mstandard we l2 Mstrid O wcscte cecivseetieneeecissieveseeeesceiieetielaniee 68 ll 1 EE 68 Muntslogieal AA 72 MUDCASCS EE 72 SCT e Sis eave ee hee cy 69 luet Ao it cee A edit ioe Seeds 79 See Ee 86 S 88 SE 88 eG Rote ee 90 SASANG SIG Soc scss 5s ven eege E eg 91 Le EN G gedon Seed de GENEE Ede Eed 92 SNE 92 PSIG Ess eege ege Ee 92 GU VE 92 SW 93 deh aA Sh eR UR A CT EE 94 SM 95 EE 95 BW a Ger deed dee ete 95 SM Sao IEEE ben dans te bo E ET 96 Commandline Options SYNTAX chet ties Aa tide eatin Senate 16 Compilation driver eceeeeeeeeeeeeeeeeeeeeeeteees 15 Compilers Invoke at command level 15 PGE YE egent deEgeehteregue AE Ed eben etic xii PGF EE xii D Data Juegd a Shining 141 DEC Structures sine 144 DEC UNIONS eccecceccecesseeeeeesssse
61. support the DEC ATTRIBUTES extensions DLLIMPORT and DLLEXPORT CDECS ATTRIBUTES DLLEXPORT object object cDEC ATTRIBUTES DLLIMPORT object object cis one of C c or object is the name of the subprogram or common block that is exported or imported Note that common block names are enclosed within slashes In example cDEC ATTRIBUTES DLLIMPORT intfunc DECS ATTRIBUTES DLLEXPORT fdata The Examples in this section further illustrate the use of these extensions To create a DLL in PVF select File New Project select PGI Visual Fortran and create a new Dynamic Library project To create a DLL from the command line use the Mmakedll option 133 The following switches apply to making and using DLLs with the PGI compilers Mdll Link with the DLL version of the runtime libraries This flag is required when linking with any DLL built by the PGI compilers Mmakedll Generate a dynamic link library or DLL Mmakeimplib Generate an import library without generating a DLL Use this flag when you want to generate an import library for a DLL but are not yet ready to build the DLL itself This situation might arise for example when building DLLs with mutual imports see Example 4 below o lt file gt Passed to the linker Name the DLL or import library lt file gt def lt file gt When used with Mmakedll this flag is passed to the linker and a def file named lt file gt is gener
62. the loop count 73 cncall Calls in parallel loops are safe to parallelize Loops containing calls are candidates for parallelization Also no minimum loop count threshold must be satisfied before parallelization will occur and last values of scalars are assumed to be safe dist block Parallelize with block distribution this is the default Contiguous blocks of iterations of a parallelizable loop are assigned to the available processors dist cyclic Parallelize with cyclic distribution The outermost parallelizable loop in any loop nest is parallelized If a parallelized loop is innermost its iterations are allocated to processors cyclically For example if there are 3 processors executing a loop processor 0 performs iterations 0 3 6 etc processor 1 performs iterations 1 4 7 etc and processor 2 performs iterations 2 5 8 etc no innermost Enable parallelization of innermost loops The default is to not parallelize innermost loops since it is usually not profitable on dual core processors noassoc Disables parallelization of loops with reductions When linking the Mconcur switch must be specified or unresolved references will result The NCPUS environment variable controls how many processors or cores are used to execute parallelized loops To set this option in PVF use the Fortran Optimization Auto Parallelization property Note This option applies only on shared memory multi processor SMP or dual
63. the result of converting an object of one data type to an object of a larger data type In the case where a scalar is used after a loop but is not defined on every iteration of the loop the compiler does not by default parallelize the loop However this option tells the compiler it s safe to parallelize the loop For a given loop the last value computed for all scalars make it safe to parallelize the loop instructs the compiler to inhibit certain optimizations and to allow for stride 0 array references This option may degrade performance and should only be used if zero stride induction variables are possible instructs the compiler to perform certain optimizations and to disallow for stride 0 array references use UNIX symbol and parameter passing conventions for Fortran subprograms Command Line Options Mvarargs force Fortran program units to assume procedure calls are to C functions with a varargs type interface Default For arguments that you do not specify the default code generation controls are as follows nodaz noflushz norecursive nostrideO noreentrant noref_externals nosignextend nosecond_underscore M lt pgflag gt Environment Controls Syntax Mnostartup instructs the linker not to link in the standard startup routine that contains the entry point _start for the program Note If you use the Mnostartup option and do not supply an entry point the linker issues the following error message Warning cannot
64. threads to use during execution of parallel regions The default value for this variable is 1 For historical reasons the environment variable NCPUS is supported with the same functionality In the event that both OMP_NUM_THREADS and NCPUS are defined the value of OMP_NUM_THREADS takes precedence NOTE OMP_NUM_THREADS threads will be used to execute the program regardless of the number of physical processors available in the system As a result you can run programs using more threads than physical processors and they will execute correctly However performance of programs executed in this manner can be unpredictable and oftentimes will be inefficient OMP_SCHEDULE specifies the type of iteration scheduling to use for DO and PARALLEL DO loops which include the SCHEDULE RUNTIME clause The default value for this variable is STATIC If the optional chunk size is not set a chunk size of is assumed except in the case of a STATIC schedule For a STATIC schedule the default is as defined in Section 6 6 DO END DO Examples of the use of OMP_SCHEDULE are as follows setenv OMP_ SCHEDULE STATIC 5 setenv OMP_ SCHEDULE GUIDED 8 setenv OMP_ SCHEDULE DYNAMIC OMP_DYNAMIC currently has no effect OMP_NESTED currently has no effect MPSTKZ increase the size of the stacks used by threads executing in parallel regions It is for use with programs that utilize large amounts of thread local storage in the form of p
65. to PGI supplied compiler libraries It also addresses the creation of dynamically linked libraries and math libraries 8 1 Creating and Using Dynamic Link Libraries on Windows Some of the PGI compiler runtime libraries are available in both static library and dynamic link library DLL form for Windows The static libraries are always used by default To use the Fortran compilers to create an executable that links to the runtime DLLs use the compiler flag Mdll at the link step There are several differences between static and dynamic link libraries Both libraries are used when resolving external references when linking an executable but the process differs for each type of library When linking with a static library the code needed from the library is incorporated into the executable When linking with a DLL external references are resolved using the DLL s import library not the DLL itself The code in the DLL associated with the external references does not become a part of the executable The DLL is loaded when the executable that needs it is run For the DLL to be loaded in this manner the DLL must be in your path Static libraries and DLLs also handle global data differently Global data in static libraries is automatically accessible to other objects linked into an executable Global data in a DLL can only be accessed from outside the DLL if the DLL exports the data and the image that uses the data imports it The Fortran compilers
66. to be a PARAMETER which was previously declared to be a subprogram argument S044 Multiple declaration for symbol A redundant declaration of a symbol has occurred For example an attempt was made to declare a symbol as an ENTRY when that symbol was previously declared as an ENTRY S045 Data type of entry point disagrees with function The current function has entry points with data types inconsistent with the data type of the current function For example the function returns type character and an entry point returns type complex S046 Data type length specifier in wrong position The CHARACTER data type specifier has a different position for the length specifier from the other data types Suppose we want to declare arrays ARRAYA and ARRAYB to have 8 elements each having an element length of 4 bytes The difference is that ARRAYA is character and ARRAYB is integer The declarations would be CHARACTER ARRAYA 8 4 and INTEGER ARRAYB 4 8 047 More than seven dimensions specified for array 048 Illegal use of si in declaration of array An asterisk may be used only as the upper bound of the last dimension 180 Messages S049 Illegal use of sr in non subroutine subprogram The alternate return specifier is legal only in the subroutine statement Programs functions and block data are not allowed to have alternate return specifiers S050 Assumed size array is not a dummy argument 051 Unrecognized built in f
67. 1 Message Format The messages are numbered but have no severity indicators because they all terminate program execution B 4 2 Message List Here are the runtime error messages 201 illegal value for specifier An improper specifier value has been passed to an I O runtime routine Example within an OPEN statement form unknown 202 conflicting specifiers Conflicting specifiers have been passed to an I O runtime routine Example within an OPEN statement form unformatted blank null 203 record length must be specified A recl specifier required for an I O runtime routine has not been passed Example within an OPEN statement access direct has been passed but the record length has not been specified recl specifier 204 illegal use of a readonly file Self explanatory Check file and directory modes for readonly status 205 SCRATCH and SAVE KEEP both specified In an OPEN statement a file disposition conflict has occurred Example within an OPEN statement status scratch and dispose keep have been passed 216 Messages 206 attempt to open a named file as SCRATCH 207 file is already connected to another unit 208 NEW specified for file that already exists 209 OLD specified for file that does not exist 210 dynamic memory allocation failed Memory allocation operations occur only in conjunction with namelist I O The most probable cause of fixed buffer overflow is exceeding the maximum numb
68. 117 Statement not allowed within a definition The statement may not appear ina STRUCTURE or derived type definition S118 Statement not allowed in DO IF or WHERE block I119 Redundant specification for Data type of indicated symbol specified more than once I120 Label is defined but never referenced I121 Operation requires logical or integer data types An operation in an expression was attempted on data having a data type incompatible with the operation For example a logical expression can consist of only logical elements of type integer or logical Real data would be invalid I122 Character string truncated Character string or Hollerith constant appearing in a DATA statement or PARAMETER statement has been truncated to fit the declared size of the corresponding identifier W123 Hollerith length specification too big reduced The length specifier field of a hollerith constant specified more characters than were present in the character field of the hollerith constant The length specifier was reduced to agree with the number of characters present 124 Relational expression mixes character with numeric data A relational expression is used to compare two arithmetic expressions or two character expressions A character expression cannot be compared to an arithmetic expression I125 Dummy procedure not declared EXTERNAL Messages 187 A dummy argument which is not declared in an EXTERNAL statement is used as the subp
69. 2 bit Microsoft Windows Operating Systems XP 2000 Server 2003 running on an x86 or x64 processor based system On these targets the PGI compiler products include additional tools and libraries needed to build executables for 32 bit Windows systems Preface xi Win64 any of the 64 bit Microsoft Windows Operating Systems XP Professional Windows Server 2003 x64 Editions running on an x64 processor based system Windows collectively all Win32 and Win64 platforms supported by the PGI compilers The following table lists the PGI compilers and tools and their corresponding commands Table P 1 PGI Compilers and Commands Compiler or Tool Language or Function Command PGF77 FORTRAN 77 pgf77 PGF95 Fortran 90 95 pgf95 PGDBG Source code debugger pgdbg PGPROF Performance profiler pgprof In general the designation PGF95 is used to refer to The Portland Group s Fortran 90 95 compiler and pgf95 is used to refer to the command that invokes the compiler A similar convention is used for each of the PGI compilers and tools For simplicity examples of command line invocation of the compilers generally reference the pgf95 command and most source code examples are written in Fortran Usage of the PGF77 compiler whose features are a subset of PGF95 is similar There are a wide variety of x86 compatible processors in use All are supported by the PGI compilers and tools Most of these processors are forward compatible bu
70. 400 IPA dummy argument is an asterisk but actual argument is not a label The subprogram expects an alternate return label for this argument E401 Actual argument is a subprogram but Dummy argument is not declared EXTERNAL The call statement passes a function or subroutine name to a dummy argument that is a scalar variable or array E402 Actual argument is illegal E403 Actual argument and formal argument have different ranks The actual and formal array arguments differ in rank which is allowed only if both arrays are declared with the HPF SEQUENCE attribute E404 Sequential array section of in argument is not contiguous When passing an array section to a formal argument that has the HPF SEQUENCE attribute the actual argument must be a whole array with the HPF SEQUENCE attribute or an array section of such an array where the section is a contiguous sequence of elements E405 Array expression argument may not be passed to sequential dummy argument When the dummy argument has the HPF SEQUENCE attribute the actual argument must be a whole array with the HPF SEQUENCE attribute or a contiguous array section of such an array unless an INTERFACE block is used E406 Actual argument and formal argument have different character lengths The actual and formal array character arguments have different character lengths which is allowed only if both character arrays are declared with the HPF SEQUENCE attribute unl
71. 64 Command Line Options pgflag Description Category no recursive allocate do not allocate local variables on the Code Generation stack this allows recursion SAVEd data initial ized or namelist members are always allocated statically regardless of the setting of this switch no reentrant specifies whether the compiler avoids optimiza Code Generation tions that can prevent code from being reentrant no ref_externals do don t force references to names appearing in EXTERNAL statements Code Generation safe_lastval In the case where a scalar is used after a loop but is not defined on every iteration of the loop the compiler does not by default parallelize the loop However this option tells the compiler it safe to parallelize the loop For a given loop the last value computed for all scalars make it safe to par allelize the loop Code Generation no nosave determines whether the compiler assumes that all Fortran Language local variables are subject to the SAVE statement no scalarsse do don t use SSE SSE2 instructions to perform Optimization scalar floating point arithmetic no second_underscore do don t add the second underscore to the name of a Fortran global if its name already contains an underscore Code Generation no signextend do don t extend the sign bit if it is set Code Generation no smart do don t enable optional AMD64 specific post
72. CH pass Ist argument to functions Yordx pass 2nd argument to functions Jorsp stack pointer Yorbp callee saved optional stack frame pointer Prsi callee saved rdi callee saved or8 pass 3rd argument to functions or9 pass 4th argument to functions r10 r11 temporary registers used in syscall sysret instructions or 12 115 callee saved registers XMM Gamm pass Ist floating point argument return value register xmm1 pass 2nd floating point argument Gamm pass 3rd floating point argument xmm3 pass 4th floating point argument xmm4 xmm5 temporary registers xmm6 xmm15 callee saved registers In addition to the registers each function has a frame on the run time stack This stack grows downward from high addresses The next table shows the stack frame organization Run time Environment 159 Table A 8 Standard Stack Frame Position Contents Frame 8n 120 rbp argument eightbyte n previous 80 rbp argument eightbyte 5 88 rbp r9 home 96 rbp r8 home 104 rbp rdx home 112 rbp rcx home 120 rbp return address current 128 rbp caller s Yorbp 0 rsp variable size Key points concerning the stack frame The parameter area at the bottom of the stack must contain enough space to hold all the parameters needed by any function call Space must be set aside for the four register parameters to be homed to the stack even if
73. CISION Double precision floating point 10 307 to 10308 1 COMPLEX See REAL See REAL DOUBLE COMPLEX See DOUBLE PRECISION See DOUBLE PRECI SION COMPLEX 16 Same as above Same as above CHARACTER n Sequence of n bytes 1 Approximate value 142 Fortran Data Types The logical constants TRUE and FALSE are all ones and all zeroes respectively Internally the value of a logical variable is true if the least significant bit is one and false otherwise When the option Munixlogical is set a logical variable with a non zero value is true and with a zero value is false Fortran Data Types 143 Table 9 2 Real Data Type Ranges Data Type Binary Range Decimal Range Digits of Precision REAL 2 126 to 2128 10 37 to 1038 7 8 REAL 8 2 1022 to 21024 10 307 to 10308 15 16 Table 9 3 Scalar Type Alignment Type Is Aligned ona LOGICAL 1 1 byte boundary LOGICAL 2 2 byte boundary LOGICAL 4 4 byte boundary LOGICAL 8 8 byte boundary BYTE 1 byte boundary INTEGER 2 2 byte boundary INTEGER 4 4 byte boundary INTEGER 8 8 byte boundary REAL 4 4 byte boundary REAL 8 8 byte boundary COMPLEX 8 4 byte boundary COMPLEX 16 8 byte boundary 9 1 2 FORTRAN 77 Aggregate Data Type Extensions The PGF77 compiler supports de facto standard extensions to FORTRAN 77 that allow for aggregate data types An aggregate data type consists of one or more scalar dat
74. DUCTION variable is included in the reduction operation If the operator intrinsic portion of the REDUCTION clause is omitted the default reduction operator is addition 106 OpenMP Directives for Fortran The COPYIN clause applies only to THREADPRIVATE common blocks In the presence of the COPYIN clause data from the master thread s copy of the common block is copied to the threadprivate copies upon entry to the parallel region In the presence of an IF clause the parallel region will be executed in parallel only if the corresponding scalar_logical_expression evaluates to TRUE Otherwise the code within the region will be executed by a single processor regardless of the value of the environment variable OMP_NUM_THREADS If the NUM_THREADS clause is present the corresponding scalar_integer_expression must evaluate to a positive integer value This value sets the maximum number of threads used during execution of the parallel region A NUM_THREADS clause overrides either a previous call to the library routine omp_set_num_threads or the setting of the OMP_NUM_THREADS environment variable 6 3 CRITICAL END CRITICAL The OpenMP END CRITICAL directive uses the following syntax SOMP CRITICAL name lt Fortran code executed in body of critical section gt SOMP END CRITICAL name Within a parallel region you may have code that will not execute properly when multiple threads act upon the same sub regio
75. E loop S305 cannot be named S306 names more than one construct S307 must have the construct name 308 DO may not terminate at an EXIT CYCLE RETURN STOP GOTO or arithmetic IF Messages 201 309 Incorrect name specified in END statement 310 Generic message for MODULE errors W311 Non replicated mapping for array ignored W312 Array should be declared SEQUENCE W313 Subprogram called within INDEPENDENT loop not PURE E314 IPA actual argument is a label but dummy argument is not an asterisk The call passes a label to the subprogram the corresponding dummy argument in the subprogram should be an asterisk to declare this as the alternate return I315 IPA routine constant dummy arguments This many dummy arguments are being replaced by constants due to interprocedural analysis I316 IPA routine INTENT IN dummy arguments This many dummy arguments are being marked as INTENT IN due to interprocedural analysis I317 IPA routine array alignments propagated This many array alignments were propagated by interprocedural analysis I318 IPA routine distribution formats propagated This many array distribution formats were propagated by interprocedural analysis I319 IPA routine distribution targets propagated This many array distribution targets were propagated by interprocedural analysis I320 IPA routine common blocks optimized This many ma
76. ECS ATTRIBUTES DLLEXPORT subl integer i common acommon adata integer adata DECS ATTRIBUTES DLLEXPORT acommon print subl adata adata print Subl i i 134 Libraries and Environment Variables adata i end progl f program progl common acommon adata integer adata external subi DECS ATTRIBUTES DLLIMPORT subl acommon adata 11 call subi 12 print main adata adata end Step 1 Create the DLL obj1 dll and its import library obj1 lib using the following series of commands pgf95 c objectl f pgf95 Mmakedll objectl obj o obji1 dll d i Step 2 Compile the main program pgf95 Mdll o progl progl f defaultlib objl The Mdll switch causes the compiler to link against the PGI runtime DLLs instead of the PGI runtime static libraries The Mdll switch is required when linking against any PGI compiled DLL such as obj1 dll The defaultlib switch is used to specify that obj1 lib the DLL s import library should be used to resolve imports Step 3 Ensure that obt dl is in your path then run the executable prog to determine if the DLL was successfully created and linked progl subl adata 11 subl i 12 main adata 12 Should you wish to change obj1 dll without changing the subroutine or function interfaces no rebuilding of prog is necessary Just recreate obj1 dll and the new obj1 dll will be loaded at runtime Example 4 Build two DLLs when each DLL is dependent on the other
77. I main programs gopt Includes debugging information in the object module but forces assembly code generation identical to that obtained when is not present on the command line I lt dirname gt Adds a directory to the search path for include files i2 i4 and i8 Treat INTEGER variables as 2 bytes i2 14 and i8 Treat INTEGER variables as 4 bytes i2 i14 and i8 Treat INTEGER and LOGICAL variables as 8 bytes and use 64 bits for INTEGER 8 operations 50 Command Line Options Option Description K lt flag gt Requests special compilation semantics with regard to conformance to TEEE 754 L lt dirname gt Specifies a library directory I lt libname gt Loads a library M lt pegflag gt Selects variations for code generation and optimization m Displays a link map on the standard output module lt moduledir gt Save search for module files in directory lt moduledir gt mp align no numa Interpret and process user inserted shared memory parallel program ming directives see Chapters 5 and 6 O lt level gt Specifies code optimization level where lt level gt is 0 1 2 or 3 0 Names the object file pc lt val gt Gm px p5 p6 piii targets only Set precision globablly for x87 float ing point calculations must be used when compiling the main pro gram lt val gt may be one of 32 64 or 80 pgf77libs Append PGF77 runtime
78. MP END PARALLEL END The SCHEDULE clause specifies how iterations of the DO loop are divided up between processors Given a SCHEDULE type chunk clause type can be STATIC DYNAMIC GUIDED or RUNTIME These are defined as follows e When SCHEDULE STATIC chunk is specified iterations are allocated in contiguous blocks of size chunk The blocks of iterations are statically assigned to threads in a round robin fashion in order of the thread ID numbers The chunk must be a scalar integer expression If chunk is not specified a default chunk size is chosen equal to number_of iterations omp_num threads 1 omp_num_threads e When SCHEDULE DYNAMIC chunk is specified iterations are allocated in contiguous blocks of size chunk As each thread finishes a piece of the iteration space it dynamically obtains the next set of iterations The chunk must be a scalar integer expression If no chunk is specified a default chunk size is chosen equal to 1 When SCHEDULE GUIDED chunk is specified the chunk size is reduced in an exponentially decreasing manner with each dispatched piece of the iteration space Chunk specifies the minimum number of iterations to dispatch each time except when there are less than chunk iterations remaining to be processed at which point all remaining iterations are assigned If no chunk is specified a default chunk size is chosen equal to 1 When SCHEDULE RUNTIME is specified the decision r
79. NCE statements have defined an address for the variable which has an alignment not optimal for variables of its data type This can occur when INTEGER and CHARACTER data are equivalenced for instance I063 Gap in common block before 064 Illegal use of in DATA statement implied DO loop The indicated variable is referenced where it is not an active implied DO index variable S065 Repeat factor less than zero S066 Too few data constants in initialization statement S067 Too many data constants in initialization statement 068 Numeric initializer for CHARACTER out of range 0 through 255 A CHARACTER 1 variable or character array element can be initialized to an integer octal or hexadecimal constant if that constant is in the range 0 through 255 S069 Illegal implied DO expression The only operations allowed within an implied DO expression are integer and S070 Incorrect sequence of statements The statement order is incorrect For instance an IMPLICIT NONE statement must precede a specification statement which in turn must precede an executable statement S071 Executable statements not allowed in block data 182 Messages 072 Assignment operation illegal to The destination of an assignment operation must be a variable array reference or vector reference The assignment operation may be by way of an assignment statement a data statement or the index variable of an implied DO loop The compiler has d
80. NE or ENTRY An alternate return can only be used if alternate return specifiers appeared in the SUBROUTINE or ENTRY statements S159 Alternate return illegal in FUNCTION subprogram An alternate return cannot be used in a FUNCTION 190 Messages 160 ENDSTRUCTURE ENDUNION or ENDMAP does not match top 161 Vector subscript must be rank one array W162 Not equal test of loop control variable replaced with lt or gt test 163 lt reserved message number gt 164 Overlapping data initializations of An attempt was made to data initialize a variable or array element already initialized S165 appeared more than once as a subprogram A subprogram name appeared more than once in the source file The message is applicable only when an assembly file is the output of the compiler 166 cannot be a common block and a subprogram A name appeared as a common block name and a subprogram name The message is applicable only when an assembly file is the output of the compiler I167 Inconsistent size of common block A common block occurs in more than one subprogram of a source file and its size is not identical The maximum size is chosen The message is applicable only when an assembly file is the output of the compiler 168 Incompatible size of common block A common block occurs in more than one subprogram of a source file and is initialized in one subprogram Its initialized size was found to be less than its size in th
81. NGLE NOWAIT Clauses PRIVATE list FIRSTPRIVATE list COPYPRIVATE list In a parallel region of code there may be a sub region of code that will only execute correctly on a single thread Instead of ending the parallel region before this subregion and then starting it up again after this subregion the SINGLE END SINGLE directive pair lets you conveniently designate code that executes on a single thread and is skipped by the other threads There is an implied barrier on exit from a SINGLE END SINGLE section of code unless the optional NOWAIT clause is specified Nested single process sections are ignored Branching into or out of a single process section is not supported PROGRAM SINGLE USE INTEGER A 0 1 INTEGER omp_get_thread_num SOMP PARALLEL A omp_get_thread_num omp_get_thread_num SOMP SINGLE PRINT YOU SHOULD ONLY SEE THIS ONCE SOMP END SINGLE SOMP END PARALLEL PRINT A O A O A 1 A 1 END The PRIVATE and FIRSTPRIVATE clauses are as described in Section 6 2 PARALLEL END PARALLEL The COPYPRIVATE clause causes the variables in list to be copied from the private copies in the single thread that executes the SINGLE region to the other copies in all other threads of the team at the end of the SINGLE region The COPYPRIVATE clause must not be used with NOWAIT 6 6 DO END DO The OpenMP DO END DO directive uses the following syntax Syntax OpenMP Directives for F
82. PVF User s Guide Parallel Fortran for Scientists and Engineers The Portland Group STMicroelectronics Two Centerpointe Drive Lake Oswego OR 97035 Optimized for amp Visual Studio While every precaution has been taken in the preparation of this document The Portland Group a wholly owned subsidiary of STMicroelectronics makes no warranty for the use of its products and assumes no responsibility for any errors that may appear or for damages resulting from the use of the information contained herein The Portland Group retains the right to make changes to this information at any time without notice The software described in this document is distributed under license from STMicroelectronics and may be used or copied only in accordance with the terms of the license agreement No part of this document may be reproduced or transmitted in any form or by any means for any purpose other than the purchaser s personal use without the express written permission of The Portland Group Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks Where those designations appear in this manual The Portland Group was aware of a trademark claim The designations have been printed in caps or initial caps Thanks is given to the Parallel Tools Consortium and in particular to the High Performance Debugging Forum for their efforts PGF95 PGF90 PGC Cluster Development Kit CDK PGI
83. PVF Fortran Module advapi32 lib WinBase h advapi32 comd g32 lib ComDlg h comdlg32 gdi32 lib WinGDI h gdi32 kernel32 lib WinBase h kernel32 shell32 lib ShellAPI h shell32 user32 lib WinUser h user32 winver lib WinVer h winver wsock32 lib WinSock h wsock32 1 17 2 Fortran Module Library Interfaces PGI Visual Fortran provides access to a number of libraries that export C interfaces by using Fortran modules This is the mechanism used by PVF to support the Win32 API and Unix Linux portability libraries To utilize any of the Win32 API interfaces for example user32 lib simply add a Fortran USE statement USE DFWIN Getting Started with PVF 11 The DFWIN module includes all the modules needed to access the Win32 API Modules supporting specific portions of the Win32 API are also available see the table in the section titled Win32 API Support for a mapping of module names to the corresponding Win32 API library and header files The function calls made through the module interfaces ultimately resolve to C Language interfaces so some accommodation for inter language calling conventions must be made in the Fortran application These issues include e On x64 platforms pointers and pointer types such as HANDLE HINSTANCE WPARAM and HWND must be treated as 8 byte quantities INTEGER 8 On x86 32 bit platforms these are 4 byte quantities INTEGER 4 In general C makes calls by value while Fortran makes calls by
84. Program Interface Version 2 5 May 2005 http www openmp org e Programming in VAX Fortran Version 4 0 Digital Equipment Corporation September 1984 IBM VS Fortran IBM Corporation Rev GC26 4119 Military Standard Fortran DOD Supplement to American National Standard Programming Language Fortran ANSI x 3 1978 MIL STD 1753 November 9 1978 S ISO IEC 9899 1999 Information technology Programming Languages C Geneva 1999 C99 Organization This manual is divided into the following chapters and appendices Chapter 1 Getting Started with PVF gives an overview of the Visual Studio environment and how to use PGI Visual Fortran in that environment Chapter 2 Getting Started with the Command Line Compilers provides an introduction to the PGI compilers and describes their use and overall features Chapter 3 Optimization amp Parallelization describes standard optimization techniques that with little effort allow users to significantly improve the performance of programs Chapter 4 Command Line Options provides a detailed description of each command line option Chapter 5 Function Inlining describes how to use function inlining and shows how to create an inline library Chapter 6 OpenMP Directives for Fortran provides a description of the OpenMP Fortran parallelization directives and shows examples of their use Chapter 7 Optimization Directives provides a descript
85. R I J COMPLEX C DOUBLE COMPLEX CD DOUBLE PRECISION D COMMON COM i j c cd d is represented in C with the following equivalent extern struct int i int j struct float real imag c struct double real imag cd double d com and in C with the following equivalent extern C struct int i in J struct float real imag c struct double real imag cd double d com_ Note that the compiler provided name of the BLANK COMMON block is implementation specific 170 Run time Environment Calling Fortran COMPLEX and CHARACTER functions from C C is not as straightforward as calling other types of Fortran functions Additional arguments must be passed to the Fortran function by the C C caller A Fortran COMPLEX function returns its value in memory the first argument passed to the function must contain the address of the storage for this value A Fortran CHARACTER function adds two arguments to the beginning of its argument list The following example of calling a Fortran CHARACTER function from C C illustrates these caller provided extra parameters CHARACTER FUNCTION CHF C1 I CHARACTER C1 INTEGER I END xtern void chf har tmp 10 har c1 9 nt i hf tmp 10 cl amp i 9 Qeaa oO The extra parameters tmp and 10 are supplied for the return value while 9 is supplied as the length of cl Refer to Section 11 6 Argument Passing and Return Values for a
86. RD 143 requires initializer W144 NEED ERROR MESSAGE This is used as a temporary message for compiler development W145 FILL only valid within STRUCTURE block The FILL special name was used outside of a STRUCTURE multiline statement It is only valid when used within a STRUCTURE multiline statement even though it is ignored 146 Expression must be character type 147 Character expression not allowed in this context 148 Reference to required Messages 189 An aggregate reference to a record was expected during statement compilation but another data type was found instead 149 Record where arithmetic value required An aggregate record reference was encountered when an arithmetic expression was expected 150 Structure Record derived type or member not allowed in this context A structure record or member reference was found in a context which is not supported For example the use of structures records or members within a data statement is disallowed S151 Empty TYPE STRUCTURE UNION or MAP TYPE ENDTYPE STRUCTURE ENDSTRUCTURE UNION ENDUNION MAP ENDMAP declaration contains no members 152 All dimension specifiers must ber 153 Array objects are not conformable 154 DISTRIBUTE target must be a processor S155 S156 Number of colons and triplets must be equal in ALIGN with 157 Illegal subscript use of ALIGN dummy S158 Alternate return not specified in SUBROUTI
87. Scalars or No Value A function that returns an integral or pointer value that fits in 64 bits places its result in rax A function that returns a floating point value that fits in the XMM registers returns this value in xmm0 A function that returns a value in memory via the stack places the address of this memory passed to the function as a hidden first argument in rcx in rax Functions that return no value also called procedures or void functions put no particular value in any register A call instruction pushes the address of the next instruction the return address onto the stack The return instruction pops the address off the stack and effectively continues execution at the next instruction after the call instruction A function that returns a scalar or no value must preserve the caller s registers as described above Additionally the called function must remove the return address from the stack leaving the stack pointer rsp with the value it had before the call instruction was executed Run time Environment 161 Functions Returning Structures or Unions A function can use either registers or the stack to return a structure or union The size and type of the structure or union determine how it is returned A structure or union is returned in memory if it is larger than 8 bytes or if its size is 3 5 6 or 7 bytes A structure or union is returned in rax if its size is 1 2 4 or 8 bytes If a structure or union i
88. TH 128 endif SUBROUTINE SUB CHARACTER PATHLENGTH path END To set this option in PVF use the Fortran Preprocessor Preprocessor Definitions property Cross reference U 54 Command Line Options dryrun Use the dryrun option to display the invocations of the compiler assembler and linker but do not execute them These invocations are command lines created by the compiler driver from the PGIRC file and the command line supplied with dryrun Default The compiler does not display individual phase invocations Usage The following command line requests verbose invocation information pgf95 dryrun myprog f Cross reference Minfo V H E Stops after the preprocessing phase Use the E option to halt the compilation process after the preprocessing phase and display the preprocessed output on the standard output Default The compiler produces an executable file Usage In the following example the compiler displays the preprocessed myprog f on the standard output pgf95 E myprog f Cross reference See the options C c Mkeepasm o F S F Stops compilation after the preprocessing phase Use the F option to halt the compilation process after preprocessing and write the preprocessed output to the file filename f where the input file is filename P Default The compiler produces an executable file Usage In the following example the compiler produces the preprocessed f
89. The file extension of the project file including the before the file extension SolutionDir The directory of the solution SolutionPath The full path name of the solution Getting Started with PVF Macro Name Description SolutionName The base name of the solution SolutionFileName The file name of the solution file SolutionExt The file extension of the solution file including the lt before the file extension TargetDir The directory of the primary output file of the build TargetPath The full path name of the primary output file of the build TargetFileName The file name of the primary output file of the build TargetExt The file extension of the primary output file of the build including the before the file extension VSInstallDir The Visual Studio 2005 installation directory VCInstallDir The Visual C 2005 installation directory If Visual C 2005 is not installed this macro may evaluate to a directory that does not exist OpenToolsDir PGI only The location of the Open Tools installation directory including files needed for building Microsoft Windows applications for both 32 bit and 64 bit environments PGITools32Dir PGI only The location of the active PGI toolset for 32 bit targets This directory is the parent of bin lib and include directories containing executables libraries and include files for th
90. Unified Binary PGI Visual Fortran PVF and The Portland Group are trademarks and PGI PGHPF PGF77 PGCC PGPROF and PGDBG are registered trademarks of STMicroelectronics Inc Other brands and names are the property of their respective owners The use of STLport a C Library is licensed separately and license distribution and copyright notice can be found in the online documentation for a given release of the PGI compilers and tools PVF User s Guide Copyright 2006 STMicroelectronics Inc All rights reserved Printed in the United States of America First Printing Release 6 2 Aug 2006 Technical support trs pgroup com Sales sales pgroup com Web http www pgroup com Contents Preface Chapter 1 ONoOaRWD 1 1 1 1 1 1 1 1 1 8 1 1 9 1 10 1 11 1 12 1 13 1 14 1 15 1 16 1 17 1 17 1 1 17 2 1 17 3 1 17 4 1 17 5 1 17 5 1 1 17 5 2 Chapter 2 2 1 2 2 2 2 1 2 2 2 2 2 3 2 3 S eege eege RE ege EE EE EEN D ee de EE et ESEN IX Audience Description eeeeeceeeeeenee cece eeeneee eee eaeeeeeetaaeeeeeetaaeeeeeeeaeeeeeneea ix Compatibility and Conformance to Gtandarde eee eer renerne nen ix OPOANIZALON EE x Hardware and Software Constraints ccccceceeeceesceeeeeeeeeeeeaeeeeeeeeessaeeneneees D eu EE xi Related Publications ccccecceeeesecceeeeeeseeeeeeeeeeeeeeeseeaaeeeseeesseneeeeeeseneees xiv Getting Started with PVF scccsssseeeees
91. Union Arguments Call Argument Stack Address i 1 s 1 8 ebp word 0 s 12 ebp word 1 s 16 ebp Implementing a Stack In general compilers and programmers must maintain a software stack Register esp is the stack pointer Register esp is set by the operating system for the application when the program is started The stack must be a grow down stack A separate frame pointer enables calls to routines that change the stack pointer to allocate space on the stack at run time e g alloca Some languages can also return values from a routine allocated on stack space below the original top of stack pointer Such a routine prevents the calling function from using esp relative addressing to get at values on the stack If the compiler does not call routines that leave esp in an altered state when they return a frame pointer is not needed and is not used if the compiler option Mnoframe is specified Although not required the stack should be kept aligned on 8 byte boundaries so that 8 byte locals are favorably aligned with respect to performance PGI s compilers allocate stack space for each routine in multiples of 8 bytes Variable Length Parameter Lists Parameter passing in registers can handle a variable number of parameters The C language uses a special method to access variable count parameters The stdarg h and varargs h files define several functions to access these parameters A C ro
92. a type objects You can declare 144 Fortran Data Types the following aggregate data types array consists of one or more elements of a single data type placed in contiguous locations from first to last structure is a structure that can contain different data types The members are allocated in the order they appear in the definition but may not occupy contiguous locations union is a single location that can contain any of a specified set of scalar or aggregate data types A union can have only one value at a time The data type of the union member to which data is assigned determines the data type of the union after that assignment The alignment of an array a structure or union an aggregate affects how much space the object occupies and how efficiently the processor can address members Arrays use the alignment of their members Array types align according to the alignment of the array elements For example an array of INTEGER 2 data aligns on a 2 byte boundary Structures and Unions align according to the alignment of the most restricted data type of the structure or union In the next example the union aligns on a 4 byte boundary since the alignment of c the most restrictive element is four STRUCTURE astr UNION MAP INTEGER 2 a 2 bytes END MAP BYTE b 1 byte END MAP MAP INTEGER 4 c 4 bytes END MAP END UNION END STRUCTURE Structure alignment can result in unused space called padding Paddin
93. able to the program logical function omp_in parallel returns TRUE if called from within a parallel region and FALSE if called outside of a parallel region When called from within a parallel region that is serialized for example in the presence of an IF clause evaluating FALSE the function will return FALSE subroutine omp_set_dynamic scalar_logical_exp is designed to allow automatic dynamic adjustment of the number of threads used for execution of parallel regions This function is recognized but currently has no effect logical function omp_get_dynamic 118 OpenMP Directives for Fortran is designed to allow the user to query whether automatic dynamic adjustment of the number of threads used for execution of parallel regions is enabled This function is recognized but currently always returns FALSE subroutine omp_set_nested scalar_logical_exp is designed to allow enabling disabling of nested parallel regions This function is recognized but currently has no effect logical function omp_get_nested is designed to allow the user to query whether dynamic adjustment of the number of threads available for execution of parallel regions is enabled This function is recognized but currently always returns FALSE double precision function omp_get_wtime returns the elapsed wall clock time in seconds as a DOUBLE PRECISION value Times returned are per thread times and are not necessarily globally consistent acr
94. aggressive hoisting and scalar replacement optimizations that may or may not be profitable To set this option O2 or O3 in PVF use the Fortran Optimization Global Optimizations property Default This table shows the interaction between the O option g option and Mvect options Table 4 3 Optimization and O g Mvect and Mconcur Options Optimize Debug M Optimization Option Option Option Level none none none 1 none none Mvect 2 none none Mconcur 2 none g none 0 O none or g none 2 Olevel none or g none level Olevel lt 2 none or g Mvect 2 Olevel lt 2 none or g Mconcur 2 Unoptimized code compiled using the option O0 can be significantly slower than code generated at other optimization levels Like the Mvect option the Munroll option sets the optimization level to level 2 if no O or g options are supplied For more information on optimization see Optimization amp Parallelization Command Line Options 87 Usage In the following example since no optimization level is specified and a O option is specified the compiler sets the optimization to level 2 pgf95 O myprog f Cross reference g M lt pgflag gt 0 Names the executable file Use the o option to specify the filename of the compiler object file The final output is the result of linking Syntax o filename Where filename is the name of the
95. am or function must be compiled with Mcache_align The Mcache_align switch has no effect on the alignment of Fortran allocatable or automatic arrays If you have arrays that are constrained for example vectors that are members of Fortran common blocks you must specifically pad your data structures to ensure proper cache alignment Mcache_align causes only the beginning address of each common block to be cache aligned The following examples show results of compiling the example code with and without Mvect sse Example 3 3 Vector operation using SSE instructions program vector_op parameter N 9999 real 4 x n y n z n w n 1 Les Tt i 4 i do j 1 200000 call loop x y z w 1 0e0 n enddo print x 1 x 771 x 3618 x 6498 x 9999 end subroutine loop a b c d s n integer i n real 4 a n b n c n d n s do i 41 n a i b i c i s dii enddo end Assume the above program is compiled as follows pgf95 fast Minfo vadd f vector op 4 Loop unrolled 4 times loop 18 Loop unrolled 4 times Following is the result if the generated executable is run and timed on a standalone AMD Opteron 2 2 Ghz system bin time a out 1 000000 771 000 3618 000 6498 00 9999 00 34 Optimization amp Parallelization 5 15user 0 00system 0 05 16 elapsed 99 CPU Now recompile with SSE vectorization enabled pgf95 fast Mvect sse Minfo vadd f vector op 4 Unrolling inner loop 8 times
96. appears in column 3 of the table above and are listed with exact syntax defaults and notes concerning similar or related options For the latest information and description of a given option or to see all available options use the help command line option to any of the PGI compilers M lt pgflag gt Syntax Mdaz Mnodaz Mdwarfl Mdwarf2 66 Code Generation Controls Set IEEE denormalized input values to zero there is a performance benefit but misleading results can occur such as when dividing a small normalized number by a denormalized number This option must be set for the main program to take effect To set this option in PVF use the Fortran Floating Point Options Treat Denormalized Values as Zero property Do not treat denormalized numbers as zero This option must be set for the main program to take effect Generate DWARF format debug information must be used in combination with g Generate DWARF format debug information must be used in combination with g Command Line Options Mdwarf3 Mflushz Mnoflushz Mfunc32 Mlarge_ arrays Mnolarge_arrays Mnomain M no movnt Mprof option option Mrecursive Mnorecursive Command Line Options Generate DWARF3 format debug information must be used in combination with g Set SSE flush to zero mode if a floating point underflow occurs the value is set to zero This option must be set for the main program t
97. arates the choices Horizontal ellipses indicate that zero or more instances of the preceding item are valid NOTE Some options do not allow a space between the option and its argument or within an argument This fact is noted in the syntax section of the respective option 49 Table 4 1 Generic PGI Compiler Options Option Description Display invocation information HHH Show but do not execute the driver commands same as dryrun byteswapio Fortran only Swap bytes from big endian to little endian or vice versa on input output of unformatted data C Instrument the generated executable to perform array bounds check ing at runtime C Stops after the assembly phase and saves the object code in file name o D lt args gt Defines a preprocessor macro dryrun Show but do not execute driver commands E Stops after the preprocessing phase and displays the preprocessed file on the standard output F Stops after the preprocessing phase and saves the preprocessed file in filename f this option is only valid for the PGI Fortran compilers fast Generally optimal set of flags for the target fastsse Generally optimal set of flags for targets that include SSE SSE2 capa bility flags Display valid driver options g Includes debugging information in the object module g77libs Linux only Allow object files generated by g77 to be linked into PG
98. are subject to the SAVE statement the compiler flags non ANSI conforming source code directs the compiler to treat logical values as true if the value is non zero and false if the value is zero UNIX F77 convention When Munixlogical is enabled a logical value or test that is non zero is TRUE and a value or test that is zero is FALSE In addition the value of a logical expression is guaranteed to be one 1 when the result is TRUE Idirects the compiler to use the VMS convention for logical values for true and false Even values are true and odd values are false the compiler allows uppercase letters in identifiers With Mupcase the identifiers X and x are different and keywords must be in lower case This selection affects the linking process if you compile and link the same source code using Mupcase on one occasion and Mnoupcase on another you may get two different executables depending on whether the source contains uppercase letters The standard libraries are compiled using the default Mnoupcase Command Line Options Mnoupcase the compiler converts all identifiers to lower case This selection affects the linking process If you compile and link the same source code using Mupcase on one occasion and Mnoupcase on another you may get two different executables depending on whether the source contains uppercase letters The standard libraries are compiled using Mnoupcase Default For arg
99. as are passed as separate command line arguments Note You cannot have a space between the W and the single letter pass identifier between the identifier and the comma or between the comma and the option Usage In the following example the linker loads the text segment at address Oxffc00000 and the data segment at address Oxffe00000 pgf95 W1 k t 0xffc00000 d 0xffe00000 myprog f W Do not print warning messages 96 Command Line Options Chapter 5 Function Inlining Function inlining replaces a call to a function or a subroutine with the body of the function or subroutine This can speed up execution by eliminating parameter passing and function subroutine call and return overhead It also allows the compiler to optimize the function with the rest of the code Note that using function inlining indiscriminately can result in much larger code size and no increase in execution speed The PGI compilers provide two categories of inlining e Automatic inlining During the compilation process a hidden pass precedes the compilation pass This hidden pass extracts functions that are candidates for inlining The inlining of functions occurs as the source files are compiled e Inline libraries You create inline libraries for example using the pgf95 command and the Mextract and o options There is no hidden extract pass but you must ensure that any files that depend on the inline library use the latest version of the inl
100. ashes i e common_blockn This directive must appear in the declarations section of a program unit after the declaration of any common blocks or variables listed On entry to a parallel region data in a THREADPRIVATE common block or variable is undefined unless COPYIN is specified on the PARALLEL directive When a common block or variable that is initialized using DATA statements appears in a THREADPRIVATE directive each thread s copy is initialized once prior to its first use The following restrictions apply to the THREADPRIVATE directive e The THREADPRIVATE directive must appear after every declaration of a thread private common block Only named common blocks can be made thread private e It is illegal for a THREADPRIVATE common block or its constituent variables to appear in any clause other than a COPYIN clause e A variable can appear in a THREADRIVATE directive only in the scope in which it is declared It must not be an element of a common block or be declared in an EQUIVALENCE statement e A variable that appears in a THREADPRIVATE directive and is not declared in the scope of a module must have the SAVE attribute OpenMP Directives for Fortran 117 6 18 Run time Library Routines User callable functions are available to the Fortran programmer to query and alter the parallel execution environment integer omp_get_num threads returns the number of threads in the team executing the parallel region from which it is
101. at are out of date then invoke pgcc to link the objects into the executable at link time pgcc will call the IPA linker to regenerate any stale or invalid IPA optimized objects 44 Optimization amp Parallelization 3 7 8 Questions about IPA Why is the object file so large An object file created with Mipa contains several additional sections One is the summary information used to drive the interprocedural analysis In addition the object file contains the compiler internal representation of the source file so the file can be recompiled at link time with interprocedural optimizations There may be additional information when inlining is enabled The total size of the object file may be 5 10 times its original size The extra sections are not added to the final executable What if I compile with Mipa and link without Mipa The PGI compilers generate a legal object file even when the source file is compiled with Mipa If you compile with Mipa and link without Mipa the linker is invoked on the original object files A legal executable will be generated while this will not have the benefit of interprocedural optimizations any other optimizations will apply What if I compile without Mipa and link with Mipa At link time the IPA linker must have summary information about all the functions or routines used in the program This information is created only when a file is compiled with Mipa If you compile a file wit
102. ata and hence apply only to vectorizable loops that operate on single precision floating point data SSE2 instructions first introduced on Pentium 4 Xeon and Opteron processors operate on double precision floating point data Prefetch instructions first introduced on Pentium III and AthlonXP processors can be used to improve the performance of vectorizable loops that operate on either 32 bit or 64 bit floating point data See table P 2 for a concise list of processors that support SSE SSE2 and prefetch instructions Note Programs units compiled with Mvect sse will not execute on Pentium Pentium Pro Pentium II or first generation AMD Athlon processors They will only execute correctly on Pentium III Pentium 4 Xeon EM64T AthlonXP Athlon64 and Opteron systems running an SSE enabled operating system 3 5 1 4 Prefetch Option The option Mvect prefetch instructs the vectorizer to automatically generate prefetch instructions when vectorizable loops are encountered even in cases where SSE or SSE2 instructions are not generated Usually explicit prefetching is not necessary on Pentium 4 Xeon and Opteron because these processors support hardware prefetching nonetheless it sometimes can be worthwhile to experiment with explicit prefetching Prefetching can be controlled on a loop by loop level using prefetch directives which are described in detail in Section 7 5 Prefetch Directives 32 Optimization amp Parallelization Note
103. ated for the DLL The def file contains the symbols exported by the DLL Generating a def file is not required when building a DLL but can be a useful debugging tool if the DLL does not contain the symbols that you expect it to contain When used with Mmakeimplib this flag is passed to lib which requires a def file to create an import library The def file can be empty if the list of symbols to export are passed to lib on the command line or explicitly marked as dllexport in the source code implib lt file gt Passed to linker Generate an import library named lt file gt for the DLL A DLL s import library is the interface used when linking an executable that depends on routines in a DLL To use the PGI compilers to create an executable that links to the DLL form of the runtime use the compiler flag Mdll The executable built will be smaller than one built without Mdll the PGI runtime DLLs however must be available on the system where the executable is run The Mdll flag must be used when an executable is linked against a DLL built by the PGI compilers The following examples outline how to use Mmakedll and Mmakeimplib to build and use DLLs with the PGI compilers Example 1 Build a DLL out of a single source file object1 f which exports data and a subroutine using DLLEXPORT Build the main source file prog f which uses DLLIMPORT to import the data and subroutine from the DLL object1 f subroutine subi i D
104. cal optimization is to change an arithmetic operation to an arithmetic operation that is mathematically correct but can be computationally different due to round off error Instructs the vectorizer to disable associativity conversions Instructs the vectorizer when performing cache tiling optimizations to assume a cache size of n The default is set using per processor type either using the tp switch or auto detected from the host computer Generate vector code for all loops where possible regardless of the number of statements in the loop This overrides a heuristic in the vectorizer that ordinarily prevents vectorization of loops with a number of statements that exceeds a certain threshold The default is nosizelimit Instructs the vectorizer to assume that the maximum vector length is less than or equal to n The vectorizer uses this information to eliminate generation of the stripmine loop for vectorized loops wherever possible If the size n is omitted the default is 100 Note No space is allowed on either side of the colon Instructs the vectorizer to search for vectorizable loops and where possible make use of SSE SSE2 and prefetch instructions To set this option in PVF use the Fortran Optimization Vectorization property Mnovect instructs the compiler not to perform vectorization can be used to override a previous instance of Mvect on the command line in particular for cases where Mvect is inc
105. called When called from a serial region this function returns 1 A nested parallel region is the same as a single parallel region By default the value returned by this function is equal to the value of the environment variable OMP_NUM_THREADS or to the value set by the last previous call to the omp_set_num_threads subroutine defined below subroutine omp_set_num_threads scalar_integer_ exp sets the number of threads to use for the next parallel region This subroutine can only be called from a serial region of code If it is called from within a parallel region or within a subroutine or function that is called from within a parallel region the results are undefined This subroutine has precedence over the OMP_NUM_THREADS environment variable integer omp_get_thread_num returns the thread number within the team The thread number lies between 0 and omp_get_num_threads 1 When called from a serial region this function returns 0 A nested parallel region is the same as a single parallel region integer function omp_get_max_threads returns the maximum value that can be returned by calls to omp_get_num_threads If omp_set_num_threads is used to change the number of processors subsequent calls to omp_get_max_threads will return the new value This function returns the maximum value whether executing from a parallel or serial region of code integer function omp_get_num procs returns the number of processors that are avail
106. cate that a selection is required In this case you must select either item2 or item3 filename ellipsis indicate a repetition Zero or more of the preceding item may occur In this example multiple filenames are allowed FORTRAN Fortran language statements are shown in the text of this guide using upper case characters and a reduced point size The PGI compilers and tools are supported on both 32 bit and 64 bit variants of the Windows operating system on a variety of x86 compatible processors The PVF User s Guide defines the following terms with respect to these platforms x86 a processor designed to be binary compatible with 1386 1486 and previous generation processors from Intel Corporation Used to refer collectively to such processors up to and including 32 bit variants IA32 an Intel Architecture 32 bit processor designed to be binary compatible with x86 processors but incorporating new features such as streaming SIMD extensions SSE for improved performance AMD64 a 64 bit processor from AMD designed to be binary compatible with IA32 processors and incorporating new features such as additional registers and 64 bit addressing support for improved performance and greatly increased memory range EM64T a 64 bit IA32 processor with Extended Memory 64 bit Technology extensions that are binary compatible with AMD64 processors x64 collectively all AMD64 and EM64T processors supported by the PGI compilers Win32 any of the 3
107. ce file or the preprocessor include directive in Fortran source files that use a F extension When linking a program with a library the linker extracts only those library components that the program needs The compiler drivers link in several libraries by default For more information about libraries refer to Chapter 8 Libraries and Environment Variables 2 3 2 Output Files By default an executable output file produced by one of the PGI compilers is placed in the file a out or on Windows a filename based on the name of the first source or object file on the command line As shown in the preceding section you can use the o option to specify the output file name 18 Getting Started with the Command Line Compilers If you use one of the options F Fortran only S or c the compiler produces a file containing the output of the last phase that completes for each input file as specified by the option supplied The output file will be a preprocessed source file an assembly language file or an unlinked object file respectively Similarly the E option does not produce a file but displays the preprocessed source file on the standard output Using any of these options the o option is valid only if you specify a single input file If no errors occur during processing you can use the files created by these options as input to a future invocation of any of the PGI compiler drivers The following table lists the stop after
108. ceeeeeeeeeeeeeees 41 Building a Program Without IPA Using Make sssr 42 Building a Program with IPA ssssessssssssssissssssrrssesrrrrssrirnnssrinrnsssrinnnssrennns 42 Building a Program with IPA Single Step ccccceeeeeeeeeeeetteeeeeeeeees 43 Building a Program with IPA Several Steps seeseeeseeeeseesereerseeereene 43 Building a Program with IPA Using Make eecseceeeeeeeteeeeeeeeneeeeeeeeee 44 Questions about IPA csere areir eadeni eier iaden a eeni 45 Profile Feedback Optimization using Mpfi Mpfo ccceeeesteeeeees 46 Default Optimization Levels cccceecccceeeececeeeeeeeeeeeeeeeeeeesaaeeseeeeeeeeaeeeeaes 46 Local Optimization Using Directives cccccccceeeeeeneeeeeteeeeeeeeeeetaeeeteneeens 47 Execution Timing and Instruction Counting cscceeeeeeeeeeteeeeeeteeeeeneeeees 48 Command Line Options ceeeeecceeeeeeeeeeeeeeeeeeseneeeeeeseeeeeeeeeeeeeees 49 Contents 4 1 Chapter 5 5 1 6 12 6 13 6 14 6 15 6 16 6 17 6 18 6 19 Chapter 7 7 1 7 2 7 3 7 4 7 5 Chapter 8 Contents Generic PGI Compiler Options 52 Function MING ebegzegreeteege eege dee ERR uEeE eg reeg 97 Invoking FUNCTION INIINING oe eee eee eeeee ee eeeeeee eee eeeeaaeeeeeeeeaaeeeeeeeeaeeeeeneeaaes 97 Using an Inline Library aidian raai eena ena a Ha LA AAAI CAA TANER KAAT ARAETA 98 Creating an Inline Library sseeseeeseeeeseeessesssernsssrsssrnssrnnesnnrnnnsrnnesnnensren 99
109. code blocks are contained in the dynamic extent of the DO directive the ORDERED clause must be present For more information on ORDERED code blocks see Section 6 14 ORDERED The DO END DO directive pair directs the compiler to distribute the iterative DO loop immediately following the OMP DO directive across the threads available to the program The DO loop is executed in parallel by the team that was started by an enclosing parallel region If the OMP END DO directive is not specified the OMP DO is assumed to end with the enclosed DO loop DO END DO directive pairs may not be nested Branching into or out of a OMP DO loop is not supported By default there is an implicit barrier after the end of the parallel loop the first thread to complete its portion of the work will wait until the other threads have finished their portion of work If NOWAIT is specified the threads will not synchronize at the end of the parallel loop Other items to note about OMP DO loops The DO loop index variable is always private 110 OpenMP Directives for Fortran e S OMP DO loops must be executed by all threads participating in the parallel region or none at all The END DO directive is optional but if it is present it must appear immediately after the end of the enclosed DO loop PROGRAM DO USE REAL A 1000 B 1000 DO I 1 1000 B I FLOAT I ENDDO SOMP PARALLEL SOMP DO DO I 1 1000 A I SQRT B I ENDDO SO
110. cription ConfigurationName The name of the current project configuration for example Debug PlatformName The name of the current project platform for example x64 dntDir The path to the directory for intermediate files relative to the project directory as set by the Intermediate Directory property OutDir The path to the directory for output files relative to the project directory as set by the Output Directory property DevEnvDir The installation directory of Visual Studio 2005 dnputDir The directory of the input file If the project is the input then this macro is equivalent to ProjectDir nputPath The full path name of the input file If the project is the input then this macro is equivalent to ProjectPath nputName The base name of the input file If the project is the input then this macro is equivalent to ProjectName nputFileName The file name of the input file If the project is the input then this macro is equivalent to ProjectFileName nputExt The file extension of the input file including the before the file extension If the project is the input then this macro is equivalent to ProjectExt ProjectDir The directory of the project ProjectPath The full path name of the project ProjectName The base name of the project ProjectFileName The file name of the project file ProjectExt
111. ct code was probably generated but it is not safe to rely on this Regardless of the severity or cause internal errors should be reported to trs pgroup com F001 Source input file name not specified On the command line source file name should be specified either before all the switches or after them F002 Unable to open source input file 174 Messages Source file name misspelled file not in current working directory or file is read protected F003 Unable to open listing file Probably user does not have write permission for the current working directory F004 Generic message for file errors F005 Unable to open temporary file Compiler uses directory usr tmp or tmp in which to create temporary files If neither of these directories is available on the node on which the compiler is being used this error will occur s006 Input file empty Source input file does not contain any Fortran statements other than comments or compiler directives F007 Subprogram too large to compile at this optimization level Internal compiler data structure overflow working storage exhausted or some other non recoverable problem related to the size of the subprogram If this error occurs at opt 2 reducing the opt level to 1 may work around the problem Moving the subprogram being compiled to its own source file may eliminate the problem If this error occurs while compiling a subprogram of fewer than 2000 statements it should b
112. ction or all functions no safeall no shape summary no vestigial in the named library are safe a safe procedure does not call back into the known procedures and does not change any known global variables Without Mipa safe any unknown procedures will cause IPA to fail declares that all unknown procedures are safe see Mipa safe default is nosafeall perform Fortran 90 array shape propagation default is noshape only collect IPA summary information when compiling this prevents IPA optimization of this file but allows optimization for other files linked with this file remove uncalled vestigial functions default is novestigial M1 re array assoc noassoc Enables loop carried redundancy elimination an optimization that can reduce the number of arithmetic operations and memory references in loops Mnolre Mnoframe Command Line Options array assoc noassoc treat individual array element references as candidates for possible loop carried redundancy elimination The default is to eliminate only redundant expressions involving two or more operands allow expression re association specifying this sub option can increase opportunities for loop carried redundancy elimination but may alter numerical results disallow expression re association Disables loop carried redundancy elimination Eliminates operations that set up a true stack frame pointer for every function With this
113. d Interprocedural analysis has verified that the prescriptive or descriptive distribution targets of this many array dummy arguments match the targets of the actual argument I392 IPA common blocks optimized Interprocedural analysis has found this many common blocks that could be optimized I393 IPA common blocks not optimized Interprocedural analysis has found this many common blocks that could not be optimized either because the common block was not declared in the main program or because it was declared differently in different subprograms I394 IPA replaced by constant value The dummy argument was replaced by a constant as per interprocedural analysis I395 IPA changed to INTENT IN The dummy argument was changed to INTENTCN as per interprocedural analysis I396 IPA array alignment propagated to The template alignment for the dummy argument was changed as per interprocedural analysis I397 IPA distribution format propagated to The distribution format for the dummy argument was changed as per interprocedural analysis I398 IPA distribution target propagated to The distribution target for the dummy argument was changed as per interprocedural analysis I399 IPA common block not optimized Messages 209 The given common block was not optimized by interprocedural analysis either because it was not declared in the main program or because it was declared differently in different subprograms E
114. d e The called function must remove this address from the stack before returning Failure of either side to meet its obligation leads to undefined program behavior The standard function calling sequence does not include any method to detect such failures nor to detect structure and union type mismatches Therefore you must declare the function properly The following table illustrates the stack contents when the function receives control after the call instruction and when the calling function again receives control after the ret instruction Run time Environment 153 Table A 3 Stack Contents for Functions Returning struct union Position After Call After Return Position 4n 8 esp argument word n argument word n 4n 4 esp 8 esp argument word 1 argument word 1 0 esp 4 esp value address undefined 0 esp return address The following sections of this appendix describe where arguments appear on the stack The examples are written as if the function prologue described above had been used ALA Argument Passing Integral and Pointer Arguments As mentioned a function receives all its arguments through the stack the last argument is pushed first In the standard calling sequence the first argument is at offset 8 ebp the second argument is at offset 12 ebp etc as previously shown in Table A 3 Stack Contents for Functions Returning struct union
115. data The DEFAULT clause lets you specify the default attribute for variables in the lexical extent of the parallel region Individual clauses specifying PRIVATE SHARED etc status override the declared DEFAULT Specifying DEFAULT NONE declares that there is no implicit default and in this case each variable in the parallel region must be explicitly listed with an attribute of PRIVATE SHARED FIRSTPRIVATE LASTPRIVATE or REDUCTION Variables that appear in the list of a FIRSTPRIVATE clause are subject to the same semantics as PRIVATE variables but in addition are initialized from the original object existing prior to entering the parallel region Variables that appear in the list of a REDUCTION clause must be SHARED A private copy of each variable in list is created for each thread as if the PRIVATE clause had been specified Each private copy is initialized according to the operator as specified in the following table Table 6 1 Initialization of REDUCTION Variables Operator Intrinsic Initialization 0 Ge 1 0 AND TRUE OR FALSE EQV TRUE NEQV FALSE MAX Smallest Representable Number MIN Largest Representable Number IAND All bits on IOR 0 IEOR 0 At the end of the parallel region a reduction is performed on the instances of variables appearing in list using operator or intrinsic as specified in the REDUCTION clause The initial value of each RE
116. data from a pgfi out profile feedback tracefile to enable or enhance certain performance optimizations Use of this option requires the presence of a pgfi out trace file in the current working directory 3 9 Default Optimization Levels The following table shows the interaction between the O g and M lt opt gt options In the table level can be 0 1 2 or 3 and lt opt gt can be vect unroll or ipa The default optimization level is dependent upon these command line options 46 Optimization amp Parallelization Table 3 1 Optimization and O g and M lt opt gt Options Optimize Debug M lt opt gt Optimization Option Option Option Level none none none 1 none none M lt opt gt 2 none g none 0 O none or g none 2 Olevel none or g none level Olevel lt 2 none or g M lt opt gt 2 03 none or g none 3 Unoptimized code compiled using the option O0 can be significantly slower than code generated at other optimization levels The M lt opt gt option where lt opt gt is vect concur unroll or ipa sets the optimization level to level 2 if no O options are supplied The fast and fastsse options set the optimization level to a target dependent optimization level if no O options are supplied 3 10 Local Optimization Using Directives Command line options let you specify optimizations for an entire source file Directives supplied within a Fortran sourc
117. dd a directory to the list of where to search for the included files The compiler searches the directory specified by the I option before the default directories stdinc Syntax Idirectory Where directory is the name of the directory added to the standard search path for include files Usage The Fortran INCLUDE statement directs the compiler to begin reading from another file The compiler uses two rules to locate the file ls If the file name specified in the INCLUDE statement includes a path name the compiler begins reading from the file it specifies 2 If no path name is provided in the INCLUDE statement the compiler searches in order e any directories specified using the I option in the order specified e the directory containing the source file e the current directory For example the compiler applies rule 1 to the following statements INCLUDE bob include filel absolute path name INCLUDE filel relative path name and rule 2 to this statement INCLUDE filel Command Line Options 57 To set this option in PVF use the Fortran General Additional Include Directories property or the Fortran Preprocessor Additional Include Directories property Cross reference Mnostdinc i2 i4 and i8 Treat INTEGER and LOGICAL variables as either two four or eight bytes INTEGER 8 values not only occupy 8 bytes of storage but operations use 64 bits instead of 32 bits K lt flag gt Requests
118. dditional information Run time Environment 171 172 Run time Environment Appendix B Messages This appendix describes the various messages that the compiler produces These messages include the sign on message and diagnostic messages for remarks warnings and errors The compiler always displays any error messages along with the erroneous source line on the screen If you specify the Mlist option the compiler places any error messages in the listing file You can also use the v option to display more information about the compiler assembler and linker invocations and about the host system For more information on the Mlist and v options refer to Chapter 4 Command Line Options BI Diagnostic Messages Diagnostic messages provide syntactic and semantic information about your source text Syntactic information includes information such as syntax errors Semantic includes information includes such as unreachable code You can specify that the compiler displays error messages at a certain level with the Minform option The compiler messages refer to a severity level a message number and the line number where the error occurs The compiler can also display internal error messages on standard errors If your compilation produces any internal errors contact you re The Portland Group s technical reporting service by sending e mail to trs pgroup com If you use the listing file option Mlist the compiler p
119. directive takes arguments c and n A c specifies that c complete unrolling should be turned on or off An n specifies that n count unrolling should be turned on or off In addition the following arguments may be added to the unroll directive cpgi unroll c v This sets the threshold to which c unrolling applies v is a constant a loop whose constant loop count is lt v is completely unrolled cpgi unroll n v This adjusts threshold to which n unrolling applies v is a constant a loop to which n unrolling applies is unrolled v times The directives unroll and nounroll only apply if Munroll is selected on the command line vector novector The directive novector is used to disable vectorization The directive vector is used to re enable vectorization after a previous novector directive The directives vector and novector only apply if Mvect has been selected on the command line vintr novintr The directive novintr directs the vectorizer to disable recognition of vector intrinsics The directive vintr is used to re enable recognition of vector intrinsics after a previous novintr directive The directives vintr and novintr only apply if Mvect has been selected on the command line 7 3 Scope of Directives and Command Line options This section presents several examples showing the effect of directives and the scope of directives Remember that during compilation the effect of a directive may be to either turn an opt
120. e PGI development environment PGIToolsDir PGI only The location of the active PGI toolset for 64 bit targets This directory is the parent of bin lib and include directories containing executables libraries and include files for the PGI development environment 1 11 Debugging with PVF PVF utilizes the Visual Studio debugger for debugging Fortran programs PGI has implemented a custom debug engine that provides the language specific debugging capability required for Fortran This debug engine also supports Visual C The Debug configuration is usually used for debugging By default this configuration will build the application so that debugging information is provided 8 Getting Started with PVF The debugger can be started by clicking on the green arrow in the toolbar looks like the play button on a CD or DVD player or by selecting Debug Start Debugging Then use the Visual Studio debugger controls as usual 1 12 Profiling with PVF Some PVF product configurations provide support for using the PGPROF performance profiler PVF profiling on Windows is a three step process First the program is built using PGI profiling options to insert calls to the PGI performance instrumentation library into the program Second the program is run when it exits a file pgprof out containing performance data is created Finally the PGPROF profiler is run to view and analyze the data in the pgprof out file On Windo
121. e 120 OMP_NUM_THREADS o 120 OMP GCHEDULE 120 OpenMP Fortran Directives cceeeeeee 103 ALOMIG coc rra i etaria eihaettenauieetaecnpess 116 BARRIER Zetegeeaieeeseeuser aine Ree 112 Index Beete 109 Daralleltzation 36 ELSE ee eine eet has 117 auto parallelization EPERE PL bet ate ee ag ie 36 NSS 0 al 5 E 108 failed auto parallelization EES 37 83 ORDERED vis ffe eseu Det ge 116 Mconcur auto parallelization 13 PARALLEL ass Senin Ale 104 NCPUS environment variable BECK PARALLEL DO steiert gereegerdereeree 113 Safe lastVall edd 39 PARALLEL SECTIONS enne 115 user directed oo eseeeeceseseseeeteesesesesetseeeseeees 86 PARALLEL WORKSHARE s sssss111111 114 Parallelization Directives 0cc eee 103 EE 114 Prefetch directives 00 ceeeseeeee eee 131 SINGLE EE 109 Preprocessor THREADPRIVATE en 117 SO a ase ek eebe 18 WORKSHARE ENEE 112 Ota er eh oer ee cess Actes 18 OpenMP Fortran Support Routines omp_destroy_lOCK EE R GE bereet Run time Environment 149 omp_get_nested omp Oet num Drocel e SS H omp_get_num_threads ccccceeeeees 118 Timing omp Oet bread num 118 CRU CLOCK oendaa a ai 48 omp_get_wtick eeeeeeeeseeeeeseeeeeneeeees 119 elle EE 48 omp_get_wtime eeeceeeeeeeeetetteeeeeeeeetees 119 SYSTEM CLOCK ji esbiugdeteekgede deed eeh 48 omp In Garallel eneee 118 Tools OMP_iNit_lOCK cccccsceseseseesesseseteeseeees 119 PGDB Gis essed eden ee ed xii
122. e file provide information to the compiler and alter the effects of certain command line options or default behavior of the compiler many directives have a corresponding command line option While a command line option affects the entire source file that is being compiled directives let you do the following e Apply or disable the effects of a particular command line option to selected subprograms or to selected loops in the source file for example an optimization Globally override command line options e Tune selected routines or loops based on your knowledge or on information obtained through profiling Chapter 7 Optimization Directives provides details on how to add directives and pragmas to your source files Optimization amp Parallelization 47 3 11 Execution Timing and Instruction Counting As this chapter shows once you have a program that compiles executes and gives correct results you may optimize your code for execution efficiency Selecting the correct optimization level requires some thought and may require that you compare several optimization levels before arriving at the best solution To compare optimization levels you need to measure the execution time for your program There are several approaches you can take for timing execution You can use shell commands that provide execution time statistics you can include function calls in your code that provides timing information or you can profile sections o
123. e other subprogram s The message is applicable only when an assembly file is the output of the compiler W169 Multiple data initializations of common block A common block is initialized in more than one subprogram of a source file Only the first set of initializations apply The message is applicable only when an assembly file is the output of the compiler Messages 191 W170 F90 extension Use of a nonstandard feature A description of the feature is provided W171 F90 extension nonstandard statement type W172 F90 extension numeric initialization of CHARACTER A CHARACTER 1 variable or array element was initialized with a numeric value W173 W174 W175 W176 W177 W178 W179 W180 w181 W182 F90 F90 F90 F90 F90 extension nonstandard use of data type length specifier extension type declaration contains data initialization extension IMPLICIT range contains nonalpha characters extension nonstandard operator extension nonstandard use of keyword argument lt reserved message number gt F90 F90 F90 F90 COMMON 192 extension use of structure field reference extension nonstandard form of constant extension amp alternate return extension mixed non character and character elements in Messages W183 IS SI W184 W185 186 187 188 189 F90 extension mixed non character and character EQUIVALENCE Mixed type elem
124. e reported to the compiler maintenance group as a possible compiler problem F008 Error limit exceeded The compiler gives up because too many severe errors were issued the error limit can be reset on the command line F009 Unable to open assembly file Probably user does not have write permission for the current working directory F010 File write error occurred Probably file system is full S011 Unrecognized command line switch Refer to PDS reference document for list of allowed compiler switches 012 Value required for command line switch Certain switches require an immediately following value such as opt 2 Messages 175 v000 Internal compiler error This message indicates an error in the compiler rather than a user error although it may be possi ble for a user error to cause an internal error The severity may vary if it is informative or warning correct object code was probably generated but it is not safe to rely on this Regardless of the severity or cause internal errors should be reported to trs pgroup com F001 Source input file name not specified On the command line source file name should be specified either before all the switches or after them F002 Unable to open source input file Source file name misspelled file not in current working directory or file is read protected F003 Unable to open listing file Probably user does not have write permission for the current w
125. e vector intrinsics vintr Drg In the case of the vector novector directive the scope is the code following the directive until the end of the routine for r scoped directives as opposed to the entire routine or until the end of the file for g scoped directives as opposed to the entire file altcode noaltcode Optimization Directives 123 Instructs the compiler to generate alternate code for vectorized or parallelized loops The noaltcode directive disables generation of alternate code This directive affects the compiler only when Mvect or Mconcur is enabled on the command line cpgi altcode cpgi altcode alignment cpgi altcode n concur cpgi altcode n concurreduction cpgi altcode n nontemporal cpgi altcode n nopeel cpgi altcode n vector 124 Enables alternate code altcode generation for vectorized loops For each loop the compiler decides whether to generate altcode and what type s to generate which may be any or all of altcode without iteration peeling altcode with non temporal stores and other data cache optimizations and altcode based on array alignments calculated dynamically at runtime The compiler also determines suitable loop count and array alignment conditions for executing the alternate code For a vectorized loop if possible generate an alternate vectorized loop containing additional aligned moves which is executed if a runtime array alignment test is pa
126. e when the actual argument has a different stride in its alignment to its template than does the dummy argument I377 Alignment offset mismatch between and This may arise when the actual argument has a different offset in its alignment to its template than does the dummy argument I378 Distribution target mismatch between and Messages 207 This may arise when the actual and dummy arguments have different distribution target sizes I379 Alignment of is too complex The alignment specification of the array is too complex for interprocedural analysis to verify or propagate the program will work correctly but without the benefit of IPA I380 Distribution format of is too complex The distribution format specification of the array is too complex for interprocedural analysis to verify or propagate the program will work correctly but without the benefit of IPA I381 Distribution target of is too complex The distribution target specification of the array is too complex for interprocedural analysis to verify or propagate the program will work correctly but without the benefit of IPA I382 IPA subprograms analyzed Interprocedural analysis succeeded in finding and analyzing this many subprograms in the whole program I383 IPA dummy arguments replaced by constants Interprocedural analysis has found this many dummy arguments in the whole program that can be replaced by constants I384 IPA dummy arguments chan
127. ed The code generator can take advantage of more possibilities for instruction grouping or filling instruction delays found within the loop Examples 2 1 and 2 2 show the effect of code unrolling on a segment that computes a dot product Optimization amp Parallelization 29 Example 3 1 Dot Product Code REAL 4 A 100 B 100 Z INTEGER I DO I 1 100 Z Z A i B i END DO END Example 3 2 Unrolled Dot Product Code REAL 4 A 100 B 100 Z INTEGER I DO I 1 100 2 Z Z A i B i Z Z A i 1 B i 1 END DO END Using the Minfo option the compiler informs you when a loop is being unrolled For example a message indicating the line number and the number of times the code is unrolled similar to the following will display when a loop is unrolled dot 5 Loop unrolled 5 times Using the c lt m gt and n lt m gt sub options to Munroll or using Mnounroll you can control whether and how loops are unrolled on a file by file basis Using directives or pragmas as specified in Chapter 7 Optimization Directives you can precisely control whether and how a given loop is unrolled See Chapter 4 Command Line Options for a detailed description of the Munroll option 3 5 Vectorization using Mvect The Mvect option is included as part of fastsse on all x86 and x64 targets If your program contains computationally intensive loops the Mvect option may be helpful If in addition you specify
128. ee paths contain directories from the same release of the PGI compilers mixing and matching different releases of the compiler executables include files and libraries can have undefined results Getting Started with PVF 3 1 6 Setting Configuration Options in PVF Visual Studio makes extensive use of property pages to specify configuration options Property pages are used to set options for compilation optimization and linking as well as how and where other tools like the debugger operate in the Visual Studio environment Some property pages apply to the whole project while others apply to a single file and can override the project wide properties The configuration options specified by the property pages apply to a specific configuration Visual Studio projects are generally created with two default configurations Debug and Release Users may create other configurations Different configurations can and usually do have different settings for configuration options Property pages can be invoked in several ways Selecting Properties from the Project menu will invoke the property pages for the currently selected item in the Solution Explorer This item may be a project a file a folder or the solution itself Right clicking the project node in the Solution Explorer and selecting Properties from the resulting context menu will invoke the project property pages Right clicking a file node and selecting Properties from the context menu will invo
129. eeeeeseeee 144 F90 derived types ssssnessesseeeesserrneerennee 146 EFopttan ainni ie ai 141 Directives Fortran eede aa de nc 17 OPUIMIZALION TEE 121 ParalleliZation c c sssscscsccceceeeeeeeeseeees 103 222 EI E 131 SCOPE ege ege e chase e ren 128 E Environment variables AAA 138 MP BIN sends ei nee 138 MP BEIS RE E 138 ME SEIN eege de tee degt eege Ee 138 MP WARN eeaeee eretan dees ee 138 ler EE 139 NCPUS_ MAX eccsesseeeceeseeeseeteseeeeeeeneees 139 NO GTOp MEGGAGE cesses 139 LNS EE EE 139 PGI CONTINUE ossee 139 140 STATIC_RANDOM_SEED ossaa 139 TIMPDIR EOE A EA EE E ee 140 F Filename Conventions sseeeeeeeeeeeeeeeeeeee 17 OXTCNSIONS EE 17 Input FileSend orenian rsen SEENEN 17 Output File A 18 Floating point stack AA 88 Fortran directive SUMMALY n se 122 Fortran Parallelization Directives ATOMIC noinen ee A 116 DOAGROSS wont ahaa eege 112 Function Inlining inlining and makefiles AAA 99 inlining examples 100 inlining restrictions eee 101 L Libraries BLAS ege egene opienie 137 8 SE 137 Re 137 LIBSE cesses E ented dats See ieene te 137 Listing Files s2 cccci ceseicaeeestee dee nenes 81 84 LOOP unrolling 0 0 eee eeeeeeeeseeeeeneeeeeseeeenaeereaes 29 Loops failed auto parallelization 0 ceeee 37 INNEMMOSE regeert aes 38 Ge 38 lu VE 38 O OpenMP environment variables MEHR ecn ei e an 120 138 OMP DYNAMIC eee eeeeeeeeeeeeeeeeeeeeeee 120 OMP NESTED a
130. egarding iteration scheduling is deferred until runtime The schedule type and chunk size can be chosen at runtime by setting the OMP_SCHEDULE environment variable If this environment variable is not set the resulting schedule is equivalent to SCHEDULE STATIC OpenMP Directives for Fortran 111 6 7 WORKSHARE END WORKSHARE The OpenMP WORKSHARE END WORKSHARE directive pair uses the following syntax Syntax SOMP WORKSHARE lt Fortran structured block to be executed in parallel gt SOMP END WORKSHARE NOWAIT The Fortran structured block enclosed by the WORKSHARE END WORKSHARE directive pair can consist only of the following types of statements and constructs Array assignments e Scalar assignments FORALL statements or constructs e WHERE statements or constructs e OpenMP ATOMIC CRITICAL or PARALLEL constructs The work implied by the above statements and constructs is split up between the threads executing the WORKSHARE construct in a way that is guaranteed to maintain standard Fortran semantics The goal of the WORKSHARE construct is to effect parallel execution of non iterative but implicitly data parallel array assignments FORALL and WHERE statements and constructs intrinsic to the Fortran language beginning with Fortran 90 The Fortran structured block contained within a WORKSHARE construct must not contain any user defined function calls unless the function is ELEMENTAL 6 8 BARRIER The OpenMP BARRIER
131. ege et EEN ES E A 12 Graphical User Interfaces cccccceceeceeeeeeeeeeeeeeeaeeeeeeeeeeeaaeeeeeeeeeeaeeneeeees 13 Menus Dialog Boxes and Resources sssssseessrirrrernssssreerrrrnrnnnenn 14 Building Windows Applications from the Command Line 00saaaaas 14 Getting Started with the Command Line Compilers 05 15 COVERVIQW detresse geed shut Bee eet Leet eege ege 15 Invoking the Command level PGI Compilers cccceeeeeeeeeeeetteeeeeees 15 Command line Syntax ccccccccceeeeeeeeeeeeeeeeeeeeeeseaaeeeeeneeesaaessseneeesiaaeeesenees 16 Command line Options c cccececeeeeeeeeeeeeeeeeeeeeaeeseceeeesaaeeseeeeeeesaaeeeeeees 17 FortraniDIreCtivies ds carccccebeantecebsh theacevhis NEEE EE E EENE ERS 17 Filename Conventions ssesesseeeieeeiesirssitresinrstnnsttnnstnnnstnnsrnnssrnnssrnnnnnns 17 iii 2 3 1 2 3 2 2 4 2 4 1 2 5 2 5 1 Chapter 3 3 1 3 2 3 3 3 3 1 3 4 3 5 3 5 1 3 5 1 1 3 5 1 2 3 5 1 3 3 5 1 4 3 5 2 3 6 3 6 1 3 6 1 1 3 6 1 2 3 6 1 3 3 6 2 3 6 2 1 3 6 2 2 3 6 2 3 3 11 Chapter 4 leie EE 17 UTPUE PIGS EE EE lee ake Cage ine ante Voie Man ears se cleat Riel oll ce 18 Parallel Programming Using the PGI Compilers s s s 20 Running SMP Parallel Programs 20 Using the PGI Compilers On Windows ccccceeeeeeeeeeeeeeteeeseeeeeteeeeens 21 Command Prompt Window ccececceceeeeeeeeeeeecaaeeeeeeeeeeaeeeseeeeessaaeeneneees 21 Op
132. egrated with Visual Studio 2005 help It can be invoked by selecting the Help Contents Help Index or Help Search menu options It can also be invoked from the Start menu via Start All Programs PGI Visual Fortran PGI Documentation Context sensitive help i e lt F1 gt help is not currently supported in PVF 1 15 The PVF Command Environment PVF provides a Start menu selection to invoke a command shell with the environment configured for the PGI compilers and tools The command line compilers and graphical tools may be invoked from this command shell without any further configuration For example to invoke the PVF command shell with the environment set for the x64 compilers and tools go to the Start menu and select Start All Programs PGI Visual Fortran PGI Visual Fortran Tools PVF Command Prompt x64 1 16 PVF Sample Projects PVF includes several examples of Fortran projects These are found under the PVF installation directory Typically this is something like VSInstallDir PGI Visual Fortran Samples These samples provide simple demonstrations of specific PVF project and solution types including e pvf_calling_vc which shows how to create a solution containing a Visual C static library and a PVF main program that links to it and calls it e pvf_dll which shows how to create a DLL that exports routines written in Fortran e menu_dialog which uses a resource file and Win32 API calls to create and control a menu and a dialog
133. ementation defined internal procedures pointer arguments assumed shape arguments functions returning arrays and functions returning derived types A 2 4 4 Interlanguage Calling Inter language calling between Fortran and C C is possible if function subroutine parameters and return values match types If a C C function returns a value call it from Fortran as a function otherwise call it as a subroutine If a Fortran function has type CHARACTER or COMPLEX call it from C C as a void function If a Fortran subroutine has alternate returns call it from C C as a Run time Environment 167 function returning int the value of such a subroutine is the value of the integer expression specified in the alternate RETURN statement If a Fortran subroutine does not contain alternate returns call it from C C as a void function The following table provides the C C data type corresponding to each Fortran data type 168 Run time Environment Arrays Table A 11 Fortran and C C Data Type Compatibility Fortran Type C C Type Size bytes CHARACTER n x char x n n REAL x float x 4 REAL 4 x float x 4 REAL 8 x double x 8 DOUBLE PRECISION x double x 8 INTEGER x int x 4 INTEGER 1 x signed char x 1 INTEGER 2 x short x 2 INTEGER 4 x int x 4 INTEGER 8 x long long x 8 LOGICAL x int x 4 LOGICAL 1 x char x 1 LOGICAL 2 x short x 2 LOGICAL 4 x int x 4 LOGICAL 8 x long long x 8
134. ent variable can be used to limit the maximum number of processes or threads used in a parallel program Attempts to dynamically set the number of processes or threads to a higher value for example using set_omp_num_threads will cause the number of processes or threads to be set at the value of NCPUS_MAX lt rather than the value specified in the function call NO_STOP_MESSAGE If this variable exists the execution of a plain STOP statement does not produce the message FORTRAN STOP The default behavior of the PGI Fortran compilers is to issue this message PGI The PGI environment variable specifies the root directory where the PGI compilers and tools are installed The default value of this variable is usr pgi In most cases the name of this root directory is derived dynamically by the PGI compilers and tools through determination of the path to the instance of the compiler or tool that has been invoked PGI_CONTINUE If the PGI_CONTINUE environment variable is set upon execution of a program compiled with Mchkfpstk the stack will be automatically cleaned up and execution will continue There is a performance penalty associated with the stack cleanup If PGI_CONTINUE is set to verbose the stack will be automatically cleaned up and execution will continue after printing of a warning message STATIC_RANDOM_ SEED The first call to the Fortran 90 95 RANDOM_SEED intrinsic without arguments will reset the random seed to a default value
135. entire region redundantly until it encounters a directive that specifies work distribution For work distribution see the DO PARALLEL DO or DOACROSS directives PROGRAM WHICH PROCESSOR AN I INTEGER A 0 1 INTEGER omp_get_thread_num A 0 1 A 1 1 SOMP PARALLEL A omp_get_thread_num omp_get_thread_num SOMP END PARALLEL PRINT A 0O A 0 A 1 A 1 END The variables specified in a PRIVATE list are private to each thread in a team In effect the compiler creates a separate copy of each of these variables for each thread in the team When an assignment to a private variable occurs each thread assigns to its local copy of the variable When operations involving a private variable occur each thread performs the operations using its local copy of the variable Important points about private variables are e Variables declared private in a parallel region are undefined upon entry to the parallel region If the first use of a private variable within the parallel region is in a right hand side expression the results of the expression will be undefined i e this is probably a coding error e Likewise variables declared private in a parallel region are undefined when serial execution resumes at the end of the parallel region OpenMP Directives for Fortran 105 The variables specified in a SHARED list are shared between all threads in a team meaning that all threads access the same storage area for SHARED
136. ents numeric and or character types in COMMON Mixed numeric and or character type EQUIVALENCE Argument missing for formal argument Too many arguments specified for Argument number to type mismatch Argument number to association of scalar actual argument to array dummy argument 190 191 192 W193 Argument number to non conformable arrays Argument number to cannot be an assumed size array Argument number to must be a label Argument number to does not match INTENT OUT Messages 193 W194 INTENT IN argument cannot be defined S195 Statement may not appear in an INTERFACE block 196 Deferred shape specifiers are required for 197 Invalid qualifier or qualifier value in OPTIONS statement An illegal qualifier was found or a value was specified for a qualifier which does not expect a value In either case the qualifier for which the error occurred is indicated in the error message S198 in ALLOCATE DEALLOCATE W199 Unaligned memory reference A memory reference occurred whose address does not meet its data alignment requirement 200 Missing UNIT FILE specifier 201 Illegal I O specifier 202 Repeated I O specifier S203 FORMAT statement has no label s204 Miscellaneous I O error 205 Illegal specification of scale factor The integer following or has been omitted or P does not follow the integer value S206 Repeat count
137. eption masking This register is initialized at process initialization time and its value must be preserved Signals can interrupt processes Functions called during signal handling have no unusual restriction on their use of registers Moreover if a signal handling function returns the process resumes its original execution path with registers restored to their original values Thus programs and compilers may freely use all registers without danger of signal handlers changing their values A 1 2 Function Return Values Functions Returning Scalars or No Value e A function that returns an integral or pointer value places its result in register eax e A function that returns a long long integer value places its result in the registers edx and eax The most significant word is placed in edx and the least significant word is placed in eax e A floating point return value appears on the top of the floating point stack The caller must then remove the value from the floating point stack even if it does not use the value Failure of either side to meet its obligations leads to undefined program behavior The standard calling sequence does not include any method to detect such failures nor to detect return value type mismatches Therefore the user must declare all functions properly There is no difference in the representation of single double or extended precision values in floating point registers 152 Run time Environment e Functio
138. er of simultaneously open file units 211 invalid file name 212 invalid unit number A file unit number less than or equal to zero has been specified 215 formatted unformatted file conflict Formatted unformatted file operation conflict 217 attempt to read past end of file 219 attempt to read write past end of record For direct access the record to be read written exceeds the specified record length 220 write after last internal record 221 syntax error in format string A runtime encoded format contains a lexical or syntax error 222 unbalanced parentheses in format string Messages 217 223 illegal P or T edit descriptor value missing 224 illegal Hollerith or character string in format An unknown token type has been found in a format encoded at run time 225 lexical error unknown token type 226 unrecognized edit descriptor letter in format An unexpected Fortran edit descriptor FED was found in a runtime format item 228 end of file reached without finding group 229 end of file reached while processing group 230 scale factor out of range 128 to 127 Fortran P edit descriptor scale factor not within range of 128 to 127 231 error on data conversion 233 too many constants to initialize group item 234 invalid edit descriptor An invalid edit descriptor has been found in a format statement 235 edit descriptor does not match item type Data types specified by I O list item and correspondin
139. ers will not parallelize innermost loops by default because it is usually not profitable You can override this default using the command line option Mconcur innermost 3 6 2 2 Timing Loops Often loops will occur in programs that are similar to timing loops The outer loop in the following example is one such loop do 1 j 1 2 do i i Sh a i b i c i lcontinue The outer loop above is not parallelized because the compiler detects a cross iteration dependence in the assignment to a i Suppose the outer loop were parallelized Then both processors would simultaneously attempt to make assignments into a 1 n Now in general the values computed by each processor for a 1 n will differ so that simultaneous assignment into a 1 n will produce values different from sequential execution of the loops In this example values computed for a 1 n don t depend on j so that simultaneous assignment by both processors will not yield incorrect results However it is beyond the scope of the compilers dependence analysis to determine that values computed in one iteration of a loop don t differ from values computed in another iteration So the worst case is assumed and different iterations of the outer loop are assumed to compute different values for a 1 n Is this assumption too pessimistic If j doesn t occur anywhere within a loop the loop exists only to cause some delay most probably to improve timing resolution And it s not
140. es correct results is not always organized for efficient execution Normally the first step in the program development process involves producing code that executes and produces the correct results This first step usually involves compiling without much worry about optimization After code is compiled and debugged code optimization and parallelization become an issue Invoking one of the PGI compiler commands with certain options instructs the compiler to generate optimized code Optimization is not always performed since it increases compilation time and may make debugging difficult However optimization produces more efficient code that usually runs significantly faster than code that is not optimized The compilers optimize code according to the specified optimization level In PVF the Fortran Optimization property page is used to specify optimization levels on the command line the O Mvect Mipa and Mconcur options are commonly used Several M lt pgflag gt switches can be used to control specific types of optimization and parallelization Options not supported by the Fortran Optimization property page can be set using the Additional Options field of the Fortran Command Line property page This chapter describes the optimization options and describes how to choose optimization options to use with the PGI compilers Chapter 5 Function Inlining describes how to use the function inlining options 3 1 Overview of Optimizat
141. es it Getting Started with the Command Line Compilers 19 The following example demonstrates the use of output filename extensions pgf95 c proto f protol F This produces the output files proto o and protol o both of which are binary object files Prior to compilation the file protol F is pre processed because it has a F filename extension 2 4 Parallel Programming Using the PGI Compilers The PGI Visual Fortran compilers support two styles of parallel programming e Automatic shared memory parallel programs compiled using the Mconcur option to pgf77 or pgf95 parallel programs of this variety can be run on shared memory parallel SMP systems such as dual core or multi processor workstations e OpenMP shared memory parallel programs compiled using the mp option to pgf77 pgf95 parallel programs of this variety can be run on SMP systems Carefully coded user directed parallel programs using OpenMP directives can often achieve significant speed ups on dual core workstations or large numbers of processors on SMP server systems Chapter 6 OpenMP Directives for Fortran contains complete descriptions of user directed parallel programming Some newer CPUs incorporate two or more complete processor cores functional units registers level 1 cache level 2 cache etc on a single silicon die These are referred to as multi core processors For purposes of threads or OpenMP parallelism these cores function as 2 or more distinct
142. ess an INTERFACE block is used W407 Argument has a different character length than dummy argument The character length of the actual argument is different than the length specified for the corresponding dummy argument 210 Messages W408 Specified main program is not a PROGRAM The main program specified on the command line is a subroutine function or block data subprogram W409 More than one main program in IPA directory and There is more than one main program analyzed in the IPA directory shown The first one found is used W410 No main program found IPA analysis fails The main program must appear in the IPA directory for analysis to proceed W411 Formal argument is DYNAMIC but actual argument is an expression W412 Formal argument is DYNAMIC but actual argument is not I413 Formal argument has two reaching distributions and may be a candidate for cloning I414 and may be aliased and one of them is assigned Interprocedural analysis has determined that two formal arguments because the same variable is passed in both argument positions or one formal argument and a global or COMMON variable may be aliased because the global or COMMON variable is passed as an actual argument If either alias is assigned in the subroutine unexpected results may occur this message alerts the user that this situation is disallowed by the Fortran standard F415 IPA fails incorrect IPA file Interprocedural analysi
143. etermined that the identifier used as the destination is not a storage location The error message attempts to indicate the type of entity used entry point An assignment to an entry point that was not a function procedure was attempted external procedure An assignment to an external procedure or a Fortran intrinsic name was attempted if the identifier is the name of an entry point that is not a function an external procedure 073 Intrinsic or predeclared cannot be passed as an argument 074 Illegal number or type of arguments to The indicated symbol is an intrinsic or generic function or a predeclared subroutine or function requiring a certain number of arguments of a fixed data type 075 Subscript substring or argument illegal in this context for This can happen if you try to doubly index an array such as ra 2 3 This also applies to substring and function references S076 Subscripts specified for non array variable S077 Subscripts omitted from array S078 Wrong number of subscripts specified for S079 Keyword form of argument illegal in this context for S080 Subscript for array is out of bounds 081 Illegal selector Messages 183 082 Illegal substring expression for variable Substring expressions must be of type integer and if constant must be greater than zero S083 Vector expression used where scalar expression required A vector expression was used in an illegal context For
144. example iscalar iarray where a scalar is assigned the value of an array Also character and record references are not vectorizable 084 Illegal use of symbol This message is used for many different errors 085 Incorrect number of arguments to statement function S086 Dummy argument to statement function must be a variable S087 Non constant expression where constant expression required S088 Recursive subroutine or function call of A function may not call itself S089 Illegal use of symbol with character length Symbols of type CHARACTER must be dummy variables and must not be used as statement function dummy parameters and statement function names Also a dummy variable of type CHARACTER cannot be used as a function S090 Hollerith constant more than 4 characters In certain contexts Hollerith constants may not be more than 4 characters long S091 Constant expression of wrong data type 092 Illegal use of variable length character expression A character expression used as an actual argument or in certain contexts within I O statements must not consist of a concatenation involving a passed length character variable W093 Type conversion of expression performed 184 Messages An expression of some data type appears in a context which requires an expression of some other data type The compiler generates code to convert the expression into the required type 094 Variable is of wrong data t
145. f code Timing functions available with the PGI compilers include 3F timing routines the SECNDS pre declared function in PGF77 or PGF95 or the SYSTEM_CLOCK or CPU_CLOCK intrinsics in PGF95 or PGHPF In general when timing a program one should try to eliminate or reduce the amount of system level activities such as program loading I O and task switching The following example shows a fragment that indicates how to use SYSTEM_CLOCK effectively within either an HPF or F90 F95 program unit Example 3 4 Using SYSTEM_CLOCK integer nprocs hz clock0O clockl real time integer allocatable t elif defined _OPENMP allocate t OMP_GET NUM THREADS else allocate t 1 endif call system_clock count_rate hz H call system_clock count clock0 lt do work gt call system_clock count clock1 t clockl1 clock0o time real sum t real hz size t 48 Optimization amp Parallelization Chapter A Command Line Options This chapter describes the syntax and operation of each compiler option The options are arranged in alphabetical order On a command line options need to be preceded by a hyphen If the compiler does not recognize an option it passes the option to the linker This chapter uses the following notation item Square brackets indicate that the enclosed item is optional item item Braces indicate that you must select one and only one of the enclosed items A vertical bar I sep
146. f file was encountered before a required endif directive was found W239 Missing argument list for A call of the indicated macro had no argument list S240 Number too long The length of a number exceeded the maximum allowed currently 2048 W241 Redefinition of symbol The indicated macro name was redefined Messages 197 I242 Redundant definition for symbol A definition for the indicated macro name was found that was the same as a previous definition F243 String too long The length of a quoted string exceeded the maximum allowed currently 2048 244 Syntax error in define formal not identifier A formal parameter that was not an identifier was used in a macro definition W245 Syntax error in define missing blank after name or arglist There was no space or tab between a macro name or argument list and the macro s definition 246 Syntax error in if A syntax error was found while parsing the expression following a if or elif directive 247 Syntax error in include The include directive was not correctly formed W248 Syntax error in line A line directive was not correctly formed W249 Syntax error in module A module directive was not correctly formed W250 Syntax error in undef A undef directive was not correctly formed W251 Token after ifdef must be identifier The ifdef directive was not followed by an identifier W252 Token after ifndef must be identifier The
147. fied common blocks optimized common blocks not optimized Bad IPA contents file Bad IPA file format Unable Unable Unable Unable to to to to create file while analyzing IPA information open file while analyzing IPA information open IPA contents file create file while collecting IPA information F345 Internal error in table overflow Analysis failed due to a table overflowing its maximum size 204 Messages W346 Subprogram appears twice The subprogram appears twice in the same source file IPA will ignore the first appearance F347 Missing ipalib option Interprocedural analysis enabled with the ipacollect ipaanalyze or ipapropagate options requires the ipalib option to specify the library directory W348 Common has different distribution target The array was declared in a common block with a different distribution target in another subprogram W349 Common has different distribution format The array was declared in a common block with a different distribution format in another subprogram W350 Common has different alignment The array was declared in a common block with a different alignment in another subprogram W351 Wrong number of arguments passed to The subroutine or function statement for the given subprogram has a different number of dummy arguments than appear in the call W352 Wrong number of arguments passed to when bound to
148. file for the compilation output The filename must not have a f extension Default The compiler creates executable filenames as needed If you do not specify the o option the default filename is the linker output file a out Usage In the following example the executable file is myprog instead of the default a out pgf95 myprog f o myprog To set this option in PVF use the Fortran Output Object File Name property Cross reference c E F S pc tp px p5 p6 piii targets only The pc option can be used to control the precision of operations performed using the x87 floating point unit and their representation on the x87 floating point stack Syntax pc 32164180 The x87 architecture implements a floating point stack using 8 80 bit registers Each register uses bits 0 63 as the significand bits 64 78 for the exponent and bit 79 is the sign bit This 80 bit real format is the default format called the extended format When values are loaded into the floating point stack they are automatically converted into extended real format The precision of the floating point stack can be controlled however by setting the precision control bits bits 8 and 9 of the floating control word appropriately In this way you can explicitly set the precision to standard IEEE double precision using 64 bits or to single precision using 32 bits The default precision is system 88 Command Line Options dependent To alter the p
149. for command line switch Certain switches require an immediately following value such as opt 2 013 Unrecognized value specified for command line switch 014 Ambiguous command line switch Too short an abbreviation was used for one of the switches W015 Hexadecimal or octal constant truncated to fit data type I016 Identifier truncated to 31 chars An identifier may be at most 31 characters in length characters after the 31st are ignored 017 Unable to open include file File is missing read protected or maximum include depth 10 exceeded Remember that the file name should be enclosed in quotes 018 Illegal label Used for label field errors or illegal values E g in fixed source form the label field first five characters of the indicated line contains a non numeric character 019 Illegally placed continuation line A continuation line does not follow an initial line or more than 99 continuation lines were specified 020 Unrecognized compiler directive Refer to user s manual for list of allowed compiler directives S021 Label field of continuation line is not blank Messages 177 The first five characters of a continuation line must be blank S022 Unexpected end of file missing END statement 023 Syntax error unbalanced Unbalanced parentheses or brackets W024 CHARACTER or Hollerith constant truncated to fit data type A character or hollerith constant was conve
150. for debugging since there is a direct correlation between the program text and the code generated Level one optimization specifies local optimization O1 The compiler performs scheduling of basic blocks as well as register allocation This optimization level is a good choice when the code is very irregular that is it contains many short statements containing IF statements and the program does not contain loops DO or DO WHILE statements For certain types of code this optimization level may perform better than level two O2 although this case rarely occurs The PGI compilers perform many different types of local optimizations including but not limited to e Algebraic identity removal Constant folding Common subexpression elimination e Local register optimization e Peephole optimizations Redundant load and store elimination Strength reductions Level two optimization O2 or O specifies global optimization The fast option generally will specify global optimization however the fast switch will vary from release to release depending on a reasonable selection of switches for any one particular release The O or O2 level performs all level one local optimizations as well as global optimizations Control flow analysis is applied and global registers are allocated for all functions and subroutines Loop regions are given special consideration This optimization level is a good choice when the program contains lo
151. g between members of the structure is called internal padding Padding between the last member and the end of the space is called tail padding The offset of a structure member from the beginning of the structure is a multiple of the member s alignment For example since an INTEGER 2 aligns on a 2 byte boundary the offset of an INTEGER 2 member from the beginning of a structure is a multiple of two bytes Fortran Data Types 145 9 1 3 Fortran 90 Aggregate Data Types Derived Types The Fortran 90 standard added formal support for aggregate data types The TYPE statement begins a derived type data specification or declares variables of a specified user defined type For example the following would define a derived type ATTENDEE TYPE ATTENDEE CHARACTER LEN 30 NAME CHARACTER LEN 30 ORGANIZATION CHARACTER LEN 30 EMAIL END TYPE ATTENDEE In order to declare a variable of type ATTENDEE and access the contents of such a variable code such as the following would be used TYPE ATTENDEE ATTLIST 100 ATTLIST 1 SNAME JOHN DOE 146 Fortran Data Types Chapter 10 Inter language Calling STDCALL The symbol name for the subroutine is constructed by pre pending an underscore converting to all lower case and appending an sign followed by an integer indicating the total number of bytes occupied by the argument list Character strings are truncated to the first character in the string which is passed by value as the first
152. g edit descriptor conflict 236 formatted record longer than 2000 characters 218 Messages 237 quad precision type unsupported 238 tab value out of range A tab value of less than one has been specified 239 entity name is not member of group 242 illegal operation on direct access file 243 format parentheses nesting depth too great 244 syntax error entity name expected 245 syntax error within group definition 246 infinite format scan for edit descriptor 248 illegal subscript or substring specification 249 error in format illegal E F G or D descriptor 250 error in format number missing after or 251 illegal character in format string 252 operation attempted after end of file Messages 219 253 attempt to read non existent record direct access 254 illegal repeat count in format 220 Messages Index Auto parallelization Bounds checking failed cache tiling EE Sak dE D n Ges Mcache_align Sdt EE 72 le aed evcistudeacsesounessveegs times Ge deeg ei 67 Mfprelaxed cccccceceseeceeeeeeeesseeeesseeteseers 75 ETE As eege e 72 SUD veces castes g et geg cate Eege eg 67 MQCCOUGS EE 83 ellene EE 75 MINOR ETGEN 84 MINING iss heii ccdicodeskevtvcapeiedioveaccosdidasbesivdues ca 70 Miomuies ia inate rnaen 72 MDa EEEa E E E E Ee 75 cMlepepaem chescesttseeecstdcapastecactas eseaderenscies 84 SEI Ge ETC 67 chMltet gesit ieee neeesa eeii 84 SMSen ies Sege ees 77
153. ged to INTENT IN Interprocedural analysis has found this many dummy arguments in the whole program that are not modified and can be declared as INTENT N W385 IPA INTENT IN dummy arguments should be INTENT INOUT Interprocedural analysis has found this many dummy arguments in the whole program that were declared as INTENT IN but should be INTENT INOUT I386 IPA array alignments propagated Interprocedural analysis has found this many array dummy arguments that could have the inherited array alignment replaced by a descriptive alignment I387 IPA array alignments verified Interprocedural analysis has verified that the prescriptive or descriptive alignments of this many array dummy arguments match the alignments of the actual argument I388 IPA array distribution formats propagated 208 Messages Interprocedural analysis has found this many array dummy arguments that could have the transcriptive distribution format replaced by a descriptive format I389 IPA array distribution formats verified Interprocedural analysis has verified that the prescriptive or descriptive distribution formats of this many array dummy arguments match the formats of the actual argument I390 IPA array distribution targets propagated Interprocedural analysis has found this many array dummy arguments that could have the transcriptive distribution target replaced by a descriptive target I391 IPA array distribution targets verifie
154. gth of the executable file name followed by an underscore and the executable file name itself The suffix is changed to oobj so linking obj does not pull in the IPA optimized objects If the IPA linker determines that the file would not benefit from any interprocedural optimizations it does not have to recompile the file at link time and will use the original object 3 8 Profile Feedback Optimization using Mpfi Mpfo The PGI compilers support many common profile feedback optimizations including semi invariant value optimizations and block placement These are performed under control of the Mpfi Mpfo command line options When invoked with the Mpfi option the PGI compilers instrument the generated executable for collection of profile and data feedback information This information can be used in subsequent compilations that include the Mpfo optimization option Mpfi must be used at both compile time and link time Programs compiled with Mpfi include extra code to collect run time statistics and write them out to a trace file When the resulting program is executed a profile feedback trace file pgfi out is generated in the current working directory Note Programs compiled and linked with Mpfi will execute more slowly due to the instrumentation and data collection overhead You should use executables compiled with Mpfi only for execution of training runs When invoked with the Mpfo option the PGI compilers use
155. guage file filename obj Windows systems only indicates an object file filename lib Windows systems only indicates a library of object files filename dll Windows systems only indicates a library of shared object files The driver passes files with s extensions to the assembler and files with o so a and lib extensions to the linker Input files with unrecognized extensions or no extension are also passed to the linker Files with a fpp suffix are first preprocessed by the Fortran compilers and the output is passed to the compilation phase The Fortran preprocessor is built in to the Fortran compilers This ensures consistency in the pre processing step regardless of the type or revision of operating system under which you re compiling Any input files not needed for a particular phase of processing are not processed For example if on the command line you use an assembly language file filename s and the S option to stop before the assembly phase the compiler takes no action on the assembly language file Processing stops after compilation and the assembler does not run in this case compilation must have been completed in a previous pass which created the s file Refer to the following section Output Files for a description of the S option In addition to specifying primary input files on the command line code within other files can be compiled as part of include files using the INCLUDE statement in a Fortran sour
156. hanged For applications with a large number of source files this can be time consuming and inefficient 3 7 2 Building a Program Without IPA Several Steps It is also possible to use individual pgcc commands to compile each source file into a corresponding object file and one to link the resulting object files into an executable d i pgf95 c filel f95 pgf95 c file2 95 pgf95 c file3 f 95 pgf95 o filel exe filel obj file2 obj file3 obj d i d i d i The pgf95 driver invokes the compiler and assembler as required to process each source file and invokes the linker for the final link command If you modify one of the source files the executable can be rebuilt by compiling just that file and then relinking pgf95 c filel f95 pgf95 o filel exe filel obj file2 obj file3 obj d i Optimization amp Parallelization 41 3 7 3 Building a Program Without IPA Using Make The program compilation and linking process can be simplified greatly using the make utility on systems where it is supported Using a file makefile containing the following lines filel exe filel obj file2 obj file3 obj pgf95 OPT o filel exe filel obj file2 obj file3 obj filel obj filel c pgf95 OPT c filel f 95 file2 obj file2 c pgf95 OPT c file2 95 file3 obj file3 c pgf95 OPT c file3 95 It is possible to type a single make command nmake The make utility determines which object files are out of date with respect to
157. hanges are required For reference and background the process of building a program without IPA is described below followed by the minor modifications required to use IPA with the PGI compilers Note that the PVF s internal build engine uses the method described as Building a Program with IPA Several Steps 40 Optimization amp Parallelization 3 7 1 Building a Program Without IPA Single Step Using the PGF95 command level compiler driver three for example source files can be compiled and linked into a single executable with one command pgf95 o filel exe filel f95 file2 f 95 file3 f95 In actuality the pgcc driver executes several steps to produce the assembly code and object files corresponding to each source file and subsequently to link the object files together into a single executable file Thus the command above is roughly equivalent to the following commands performed individually d i pgf95 S o filel s filel f95 as o filel obj filel s pgf95 S o file2 s file2 f 95 as o file2 obj file2 s pgf95 S o file3 s file3 f95 as o file3 obj file3 s pgf95 o filel exe filel obj file2 obj file3 obj d i dp d oP ol d i If any of the three source files is edited the executable can be rebuilt with the same command line pg95 o filel exe filel f 95 file2 95 file3 f 95 This always works as intended but has the side effect of recompiling all of the source files even if only one has c
158. he O3 Minline and Mconcur options may be accessed using the Global Optimizations Inlining and Auto Parallelization properties on the Fortran Optimization property page respectively Three other options which are extremely useful are help Minfo and dryrun You can see a specification of any command line option by invoking any of the PGI compilers with help in combination with the option in question without specifying any input files For example pgf95 help fastsse Reading rcfile usr pgi_rel linux86 64 6 0 bin pgf95re fastsse fast Mvect sse Mcache align Mflushz fast Common optimizations 02 Munroll c 1 Mnoframe Mlre Optimization amp Parallelization 25 Or to see the full functionality of help itself which can return information on either an individual option or groups of options by type pgf95 help help Reading rcfile usr pgi_rel linux86 64 6 0 bin pgf95rc help groups asm debug language linker opt other overal1 phase prepro suffix switch target variable In PVF these options may be accessed via the Fortran Command Line property page or perhaps more appropriately for the help option via a Build Event or Custom Build Step The Minfo option can be used to display compile time optimization listings When this option is used the PGI compilers will issue informational messages to stdout as compilation proceeds From these messages you can determine which loops
159. he Properties Window is visible selecting a file will show that file s properties To include a source file in the build make sure the IsIncludeFile property is set to False To exclude a source file from the build set IsIncludeFile to True 4 Getting Started with PVF To change whether a source file is compiled as fixed format or free format source set the IsFixedFormat property appropriately PVF uses file extensions to determine the format style the f extension implies fixed format and other extensions such as f90 or f95 imply free format Note that the C and comment characters are only valid for fixed format compilation 1 8 Building a Project with PVF Once a PVF project has been created populated with source files and any necessary configuration settings have been made the project can be built The easiest way to start a build is to use the Build Build Solution menu selection all projects in the solution will be built If there are compile time errors the Error List window will be displayed showing a summary of the errors that were encountered If the error message shows a line number then double clicking the error record in the Error List window will navigate to the location of the error in the editor window When a project is built for the first time PVF must determine the build dependencies Build dependencies are the result of USE or INCLUDE statements or include preprocessor directives in the source I
160. his task by resolving all math routines in the library libm performing a function call of necessity The other method of generating a function call for math routines but one that may still produce the inline instructions is by using the Kieee switch A second example illustrates the precision control problem using a section of code to determine machine precision program find precision w 1 0 100 W W W y w 1 Z y w if z gt 0 goto 100 C now w is just big enough that w 1 w 1 gt 1 print w end In this case where the variables are implicitly real 4 operations are performed on the floating point stack where optimization removed unnecessary loads and stores from memory The general case of copy propagation being performed follows this pattern 1 According to Intel documentation this only affects the x87 operations of add subtract multiply divide and square root In particular it does not appear to affect the x87 tran scendental instructions Command Line Options 89 Sien wv se 2 0 rt a Instead of storing x into a then loading a to perform the addition the value of x can be left on the floating point stack and added to 2 0 Thus memory accesses in some cases can be avoided leaving answers in the extended real format If copy propagation is disabled stores of all left hand sides will be performed automatically and reloaded when needed This will have the effect of rounding any results to their declared size
161. hout Mipa and then try to get interprocedural optimizations by linking with Mipa the IPA linker will issue a message that some routines have no IPA summary information and will proceed to run the system linker using the original object files If some files were compiled with Mipa and others were not it will determine the safest approximation of the IPA summary information for those files not compiled with Mipa and use that to recompile the other files using interprocedural optimizations Can I build multiple applications in the same directory with Mipa Yes Suppose you have three source files main1 f95 main2 f95 sub f95 where sub f95 is shared between the two applications When you build the first application with Mipa pgf95 o appl mainl f95 sub f95 the IPA linker will create two IPA optimized object files mainl ipa4 appl exe oobj sub ipa4 appl exe oobj and use them to build the first application When you build the second application pgf95 o app2 main2 f95 sub f95 the IPA linker will create two more IPA optimized object files main2 ipa4 app2 exe oobj sub ipa4 app2 exe oobj Note there are now three object files for sub f95 the original sub obj and two IPA optimized objects one for each application in which it appears Optimization amp Parallelization 45 How is the mangled name for the IPA optimized object files generated The mangled name has _ipa appended followed by the decimal number of the len
162. ical differences from the generated executable Certain vectorizable operations for example dot products are sensitive to order of operations and the associative transformations necessary to enable vectorization or parallelization Optimization amp Parallelization 35 3 6 Auto Parallelization using Mconcur With the Mconcur option the compiler scans code searching for loops that are candidates for auto parallelization Mconcur must be used at both compile time and link time When the parallelizer finds opportunities for auto parallelization it parallelizes loops and you are informed of the line or loop being parallelized if the Minfo option is present on the compile line See Chapter 4 Command Line Options for a complete specification of Mconcur In PVE the basic form of this option is accessed using the Auto Parallelization property of the Fortran Optimization property page For more advanced auto parallelization use the Fortran Command Line property page A loop is considered parallelizable if doesn t contain any cross iteration data dependencies Cross iteration dependencies from reductions and expandable scalars are excluded from consideration enabling more loops to be parallelizable In general loops with calls are not parallelized due to unknown side effects Also loops with low trip counts are not parallelized since the overhead in setting up and starting a parallel loop will likely outweigh the potential benefits I
163. ile from which they were extracted the version number of the extractor which created the entry etc Libraries and their elements can be manipulated using ordinary system commands e Inline libraries can be copied or renamed e Elements of libraries can be deleted or copied from one library to another The Is command can be used to determine the last change date of a library entry Dependencies in Makefiles When a library is created or updated using one of the PGI compilers the last change date of the library directory is updated This allows a library to be listed as a dependence in a makefile and ensures that the necessary compilations will be performed when a library is changed 5 2 2 Updating Inline Libraries Makefiles If you use inline libraries you need to be certain that they remain up to date with the source files into which they are inlined One way to assure inline libraries are updated is to include them in a makefile The makefile fragment in the following example assumes the file utils f contains a number Function Inlining 99 of small functions used in the files parser f and alloc f The makefile also maintains the inline library utils il The makefile updates the library whenever you change utils f or one of the include files it uses In turn the makefile compiles parser f and alloc f whenever you update the library Example 5 1 Sample Makefile SRC mydir FC pgf95 FFLAGS 02 main o SRC main f SRC
164. ile myprog f in the current directory pgf95 F myprog F Cross reference c E Mkeepasm o S fast A generally optimal set of options is chosen depending on the target system Cross reference O Munroll Mnoframe Mvect tp Mscalarsse Command Line Options 55 fastsse A generally optimal set of options is chosen for targets that support SSE capability In addition the appropriate tp option is automatically included to enable generation of code optimized for the type of system on which compilation is performed Note Auto selection of the appropriate tp option means that programs built using the fastsse option on a given system are not necessarily backward compatible with older systems Cross reference O Munroll Mnoframe Mscalarsse Mvect Mcache_align tp flags Displays driver options on the standard output Use this option with v to list options that are recognized and ignored as well as the valid options Cross reference H v G Linux only Passed to the linker Instructs the linker to produce a shared object file Cross reference shared R The g option instructs the compiler to include symbolic debugging information in the object module Debuggers such as PGDBG require symbolic debugging information in the object module to display and manipulate program variables and source code Note that including symbolic debugging inf
165. imp when used in combination with the mp option Miscellaneous causes the compiler to ignore SGI style parallel ization directives or pragmas but still process OpenMP directives or pragmas nostartup do not link in the standard startup routine Environment nostdinc instructs the compiler to not search the standard Environment location for include files To set this option in PVF use the Fortran Prepro cessor I gnore Standard Include Path property nostdlib instructs the linker to not link in the standard Environment libraries noonetrip determines whether each DO loop executes at Language least once novintr disable idiom recognition and generation of calls Optimization to optimized vector functions pfi instrument the generated code and link in libraries Optimization for dynamic collection of profile and data infor mation at runtime pfo read a pgfi out trace file and use the information Optimization to enable or guide optimizations no prefetch disable enable generation of prefetch instruc Optimization tions preprocess perform cpp like preprocessing on assembly lan Miscellaneous guage and Fortran input source files prof set profile options function level and line level Code Generation profiling are supported nor8 determines whether the compiler promotes REAL Optimization variables and constants to DOUBLE PRECI SION nor8intrinsics determines how the compiler treats the intrinsics Optimization CMPLX and REAL
166. in the calling function If the called function is not prototyped the calling convention uses the types of the arguments but promotes char or short to int and unsigned char or unsigned short to unsigned int and promotes float to double unless you use the Msingle option For more information on the Msingle option refer to Chapter 3 If the called function is prototyped the unused bits of a register containing a char or short parameter are undefined and the called function must extend the sign of the unused bits when needed Calling Assembly Language Programs Example A 3 C Program Calling an Assembly language Routine File testmain c main long 1 paral 0x3f 800000 float para2 1 0 double d_para3 0 5 float f return extern float sum_3 long paral float para2 double para3 f return sum_3 1 paral f _para2 d_para3 j printf Parameter one type long 08x n 1 paral printf Parameter two type float f n f para2 printf Parameter three type double Sonn d_para3 printf The sum after conversion f n f return File sum 3 s Computes paral para2 para3 text 164 Run time Environment align 16 globl sum 3 sum_3 pushq srbp leaq 128 rsp srbp cvtsi2ss ecx xmm0 addss xmml xmm0O cvtss2sd xmm0 xmm0 addsd Sxmm2 xmm0O cvtsd2ss xmm0 xmm0 popg srbp ret type sum_3 function size sum_3 sum_3 A 2 4 Win64 Fortran Supplement Sections A3 4 1 th
167. inary code including full optimizations and support for both AMD and Intel x64 processors See Table 2 Processor Options for a concise list of the features of these processors that distinguish them as separate targets when using the PGI compilers and tools Syntax for 64 bit targets tp k8 64 k8 64e p7 64 core2 64 x64 Syntax for 32 bit targets tp k8 32 p6 p7 core2 piii px Usage In the following example pgf95 sets the target architecture to EM64T pgf95 tp p7 64 myprog f Default The default style of code generation is auto selected depending on the type of processor on which compilation is performed The tp x64 style of unified binary code generation is only enabled by an explicit tp x64 option U Undefines a preprocessor macro Use the U option or the undef preprocessor directive to undefine macros Syntax Usymbol Where symbol is a symbolic name Usage The following examples undefine the macro test pgf95 Utest myprog F pgf95 Dtest Utest myprog F To set this option in PVF use the Fortran Preprocessor Undefine Preprocessor Definitions property Cross reference D _Mnostdde 94 Command Line Options V release_number Displays additional information including version messages If a release_number is appended the compiler driver will attempt to compile using the specified release instead of the default release There can be no space between V and release numbe
168. ine library There are important restrictions on inlining Inlining only applies to certain types of functions Refer to Section 5 5 Restrictions on Inlining at the end of this chapter for more details on function inlining limitations 5 1 Invoking Function Inlining To invoke the function inliner use the Minline option If you do not specify an inline library the compiler performs a special prepass on all source files named on the compiler command line before it compiles any of them This pass extracts functions that meet the requirements for inlining and puts them in a temporary inline library for use by the compilation pass In PVF inlining can be turned on using the nlining property in the Fortran Optimization property page for more advanced configuration of inlining use the Fortran Command Line property page Several Minline options let you determine the selection criteria for functions to be inlined These selection criteria include except func Inline all eligible functions except func a function in the source text Multiple functions can be listed comma separated name func A function name which is a string matching func a function in the source text size n A size which instructs the compiler to select functions with a statement count less than or equal to n the specified size Note the size n may not exactly equal the number of statements in a selected function the size parameter is used as a ro
169. ion In general optimization involves using transformations and replacements that generate more efficient code This is done by the compiler and involves replacements that are independent of the particular target processor s architecture as well as replacements that take advantage of the x86 or x64 architecture instruction set and registers For the discussion in this and the following chapters optimization is divided into the following categories Local Optimization This optimization is performed on a block by block basis within a program s basic blocks A basic block is a sequence of statements in which the flow of control enters at the beginning and leaves at the end without the possibility of branching except at the end The PGI compilers perform many types of local optimization including algebraic identity removal constant folding common sub expression elimination pipelining redundant load and store elimination scheduling strength reduction and peephole optimizations 23 Global Optimization This optimization is performed on a program unit over all its basic blocks The optimizer performs control flow and data flow analysis for an entire program unit All loops including those formed by IFs and GOTOs are detected and optimized Global optimization includes constant propagation copy propagation dead store elimination global register allocation invariant code motion and induction variable elimination Loop Optimizati
170. ion of each Fortran optimization directive and shows examples of their use Chapter 8 Libraries and Environment Variables discusses PGI support libraries shared object files and environment variables that affect the behavior of the PGI compilers Chapter 9 Fortran Data Types describes the data types that are supported by the PGI Fortran compilers Chapter 10 Inter language Calling provides examples showing how to place C Language calls in a Fortran program and Fortran Language calls in a C program Appendix A Run time Environment describes the assembly language calling conventions and examples of assembly language calls Appendix B Messages provides a list of compiler error messages Hardware and Software Constraints This guide describes versions of PGI Visual Fortran that are intended for use on x86 and x64 processor based systems Details concerning environment specific values and defaults and system specific features or limitations are presented in the release notes delivered with PGI Visual Fortran x Preface Conventions The PVF User s Guide uses the following conventions italic is used for commands filenames directories arguments options and for emphasis Constant Width is used in examples and for language statements in the text including assembly language statements item square brackets indicate optional items In this case item1 is optional item2 item 3 braces indi
171. ion on or turn an option off Directives apply to the section of code following the directive corresponding to the specified scope that is the following loop the following routine or the rest of the program Consider the following code integer maxtime time parameter n 1000 maxtime 10 double precision a n n b n n c n n do time 1 maxtime do 4 1 T do j 1 n 128 Optimization Directives c i j a i j b i j enddo enddo enddo end When compiled with Mvect both interior loops are interchanged with the outer loop pgf95 Mvect dirvectl f Directives alter this behavior either globally or on a routine or loop by loop basis To assure that vectorization is not applied use the novector directive with global scope cpgi g novector integer maxtime time parameter n 1000 maxtime 10 double precision a n n b n n c n n do time 1 maxtime do i 1 n dogi yn Gite A Ae BCL yy enddo enddo enddo end In this version the compiler disables vectorization for the entire source file Another use of the directive scoping mechanism turns an option on or off locally either for a specific procedure or for a specific loop integer maxtime time parameter n 1000 maxtime 10 double precision a n n b n n c n n cpgi l novector do time 1 maxtime do i 1 n do j 1 n e i j a i j b i j enddo enddo enddo end Loop level scoping does not apply to nested l
172. ion using SSE instructions the vectorizer recognizes the vector operation in subroutine loop when the compiler switch Mvect sse is used This example shows the compilation informational messages and runtime results using the SSE instructions on an AMD Opteron processor based system along with issues that affect SSE performance First note that the arrays in Example 3 3 Vector operation using SSE instructions are single precision and that the vector operation is done using a unit stride loop Thus this loop can potentially be vectorized using SSE instructions on any processor that supports SSE or SSE2 instructions SSE operations can be used to operate on pairs of single precision floating point numbers and do not apply to double precision floating point numbers SSE2 instructions can be used to operate on quads of single precision floating point numbers or on pairs of double precision floating point numbers Loops vectorized using SSE or SSE2 instructions operate much more efficiently when processing vectors that are aligned to a cache line boundary You can cause unconstrained data objects of size 16 bytes or greater to be cache aligned by compiling with the Mcache_align switch An unconstrained data object is a data object that is not a common block member and not a member of an aggregate data structure Optimization amp Parallelization 33 Note In order for stack based local variables to be properly aligned the main progr
173. ive DECS DISTRIBUTE POINT This directive is front end based and tells the compiler at what point within a loop to split into two loops subroutine dist a b n integer i integer n integer a integer b do i 1 n 130 Optimization Directives a i a i 2 DECS DISTRIBUTE POINT b i b i 4 enddo end subroutine DECS DISTRIBUTEPOINT is same as DEC DISTRIBUTE POINT ALIAS Attribute DECS ALIAS same as DEC ATTRIBUTES ALIAS 7 5 Prefetch Directives When vectorization is enabled using the Mvect or Mprefetch compiler options or an aggregate option such as fastsse that incorporates Mvect the PGI compilers selectively emit instructions to explicitly prefetch data into the data cache prior to first use It is possible to control how these prefetch instructions are emitted using prefetch directives These directives only have an effect when vectorization or prefetching are enabled on the command line or by PVF properties See Table 2 Processor Options in the Preface for a list of processors that support prefetch instructions The syntax of a prefetch directive is as follows cSmem prefetch lt varli gt lt var2 gt where lt varn gt is any valid variable or array element reference NOTE The sentinel for prefetch directives is c mem which is distinct from the cpgi sentinel used for optimization directives Any prefetch directives that use the cpgi sentinel will be ignored by
174. ives may be repeated as needed subject to the restrictions listed in the description of each clause The compiler option mp enables recognition of the parallelization directives The use of this option also implies Mreentrant local variables are placed on the stack and optimizations that may result in non reentrant code are disabled e g Mnoframe Miomutex critical sections are generated around Fortran I O statements In PVF the mp option is set using the Process OpenMP Directives property in the Fortran Language property page Many of the directives are presented in pairs and must be used in pairs In the examples given with each section the routines omp_get_num_threads and omp_get_thread_num are used refer to Section 6 18 Run time Library Routines for more information They return the number of threads currently in the team executing the parallel region and the thread number within the team respectively 6 2 PARALLEL END PARALLEL The OpenMP PARALLEL END PARALLEL directive is supported using the following syntax Syntax SOMP PARALLEL Clauses lt Fortran code executed in body of parallel region gt SOMP END PARALLEL Clauses PRIVATE list SHARED list DEFAULT PRIVATE SHARED NONE FIRSTPRIVATE list REDUCTION operator intrinsic list COPYIN list IF scalar_logical_ expression NUM_THREADS scalar_integer_expression This directive pair declares a region of parallel exec
175. ke that file s property pages The property page dialog displays the current configuration and platform in combo or drop down boxes across the top of the dialog The configuration can be changed to All Configurations so the property is changed for all configurations A common error is to change a property like Additional Include Directories for the Debug configuration but not the Release configuration thereby breaking the build of the Release configuration In the PVF documentation compiler options are described in terms of the corresponding command line options For compiler options that can be set using the PVF property pages the description of the option includes instructions on how to do so Each tool supported by PVF compiler linker etc has a Command Line property page where the command line derived from the properties can be seen Options that are not supported by the PVF property pages can be added to the command line from this property page by entering them into the Additional Options field 1 7 Setting File Properties in PVF Visual Studio also supports properties that are not configuration properties For example whether or not a file is an include file is not configuration specific it is a property of the file whether in the Debug or Release configuration View and modify this type of property in the Properties Window The Properties Window can be accessed via the View Properties Window menu selection Once t
176. laces diagnostic messages after the source lines in the listing file in the following format PGFTN etype enum message filename line Where etype is a character signifying the severity level enum is the error number message is the error message filename is the source filename line is the line number where the compiler detected an error 173 B 2 Phase Invocation Messages You can display compiler assembler and linker phase invocations by using the v command line option For further information about this option see Chapter 4 Command Line Options BA Fortran Compiler Error Messages This section presents the error messages generated by the PGF77 and PGF95 compilers The compilers display error messages in the program listing and on standard output and can also display internal error messages on standard error B 3 1 Message Format Each message is numbered Each message also lists the line and column number where the error occurs A dollar sign in a message represents information that is specific to each occurrence of the message B 3 2 Message List Error message severities I informative WwW warning S severe error F fatal error V variable v000 Internal compiler error This message indicates an error in the compiler rather than a user error although it may be possi ble for a user error to cause an internal error The severity may vary if it is informative or warning correct obje
177. lly related in some way PVF projects are reference based projects which means that although there can be folders in the representation of the project in the Solution Explorer there are not necessarily any corresponding folders in the file system Similarly files added to the project can be located anywhere in the file system adding them to the project does not copy them or move them to a project folder in the file system The PVF project system keeps an internal record of the location of all the files added to a project 2 Getting Started with PVF 1 4 PVF Editor Features The PVF Editor provides several Fortran aware features to ease the task of entering and examining Fortran code Source Colorization Fortran source is colorized so that keywords comments and strings are distinguished from other language elements Using the Tools Options Environment Fonts and Colors property page colors can be assigned for identifiers and numeric constants and the existing colors for strings keywords and comments can be changed Method Tips Fortran intrinsic functions are supported with method tips When an opening parenthesis is entered in the source editor following an intrinsic name a method tip pop up is displayed that shows the data types of the arguments to the intrinsic function If the intrinsic is a generic function supporting more than one set of arguments the method tip window supports scrolling through the supported argument lists
178. luded in an aggregate option such as fastsse Mnovintr 80 Command Line Options instructs the compiler not to perform idiom recognition or introduce calls to hand optimized vector functions Default For arguments that you do not specify the default optimization control options are as follows depchk noprefetch i4 nounroll nofprelaxed novect noipa nor8 nolre nor8intrinsics If you do not supply an option to Mvect the compiler uses defaults that are dependent upon the target system Usage In this example the compiler invokes the vectorizer with use of packed SSE instructions enabled pgf95 Mvect sse Mcache align myprog f Cross reference g O M lt pgflag gt Syntax Manno Mbounds Command Line Options Miscellaneous Controls annotate the generated assembly code with source code when either the S or Mkeepasm options are used To set this option in PVF use the Fortran Output Annotated ASM Listing property enables array bounds checking If an array is an assumed size array the bounds checking only applies to the lower bound If an array bounds violation occurs during execution an error message describing the error is printed and the program terminates The text of the error message includes the name of the array the location where the error occurred the source file and the line number in the source and information about the out of bounds subscript its value its lo
179. ly optimal for the target Use help to see the settings for Mipa fast on a given target force all objects to re compile regardless of whether IPA information has changed optimize references to global variables default is noglobals perform automatic function inlining If the optional n is provided limit inlining to at most n levels IPA based function inlining is performed from leaf routines upward save IPA information in a ipo file rather than incorporating it into the object file keep the optimized object files using file name mangling to reduce re compile time in subsequent builds default is keepobj optimize calls to certain standard C library routines default is nolibc allow inlining of routines from libraries implies Mipa inline default is nolibinline allow recompiling and optimization of routines from libraries using IPA information default is nolibopt equivalent to arg plus externalization of local pointer targets default is nolocalarg specify a function to appear as a global entry point may appear multiple times disables linking enable pointer disambiguation across procedure calls default is noptr pure function detection default is nopure Command Line Options required return an error condition if IPA is inhibited for any reason rather than the default behavior of linking without IPA optimization safe lt function gt l lt library gt declares that the named fun
180. ly use fast for older x86 processors as described in the following section 3 3 1 Scalar SSE Code Generation For all processors prior to Intel Pentium 4 and AMD Opteron Athlon64 for example Intel Pentium HI and AMD AthlonXP MP processors scalar floating point arithmetic as generated by the PGI Workstation compilers is performed using x87 floating point stack instructions With the advent of SSE SSE2 instructions on Intel Pentium 4 Xeon and AMD Opteron Athlon64 it is possible to perform all scalar floating point arithmetic using SSE SSE2 instructions In most cases this is beneficial from a performance standpoint The default on 32 bit Intel Pentium I II tp p6 tp piii etc or AMD AthlonXP MP tp k7 is to use x87 instructions for scalar floating point arithmetic The default on Intel Pentium 4 Xeon or Intel EM64T running a 32 bit operating system tp p7 AMD Opteron Athlon64 running a 32 bit operating system tp k8 32 or AMD Opteron Athlon64 or Intel EM64T processors running a 64 bit operating system tp k8 64 and tp p7 64 respectively is to use SSE SSE2 instructions for scalar floating point arithmetic The only way to override this default on AMD Opteron Athlon64 or Intel EM64T processors running a 64 bit operating system is to specify an older 32 bit target for example tp k7 or tp piii In PVF the tp option is accessed using the Processor Specific Optimization property in the Fortran Optimization property page
181. me f Default The compiler produces an executable file does not use the c option Usage In this example the compiler produces the object file myprog o in the current directory Command Line Options 53 pgf95 c myprog f Cross reference P Mkeepasm o and S D Defines a preprocessor macro Use the D option to create a macro with a given value The value must be either an integer or a character string You can use the D option more than once on a compiler command line The number of active macro definitions is limited only by available memory You can use macros with conditional compilation to select source text during preprocessing A macro defined in the compiler invocation remains in effect for each module on the command line unless you remove the macro with an undef preprocessor directive or with the U option The compiler processes all of the U options in a command line after processing the D options Syntax Dname value Where name is the symbolic name and value is either an integer value or a character string Default If you define a macro name without specifying a value the preprocessor assigns the string 1 to the macro name Usage In the following example the macro PATHLENGTH has the value 256 until a subsequent compilation If the D option is not used PATHLENGTH s value is set to 128 pgf95 DPATHLENGTH 256 myprog F Where the source text is ifndef PATHLENGTH define PATHLENG
182. ming the MAX calculation in the loop using MX directly rather than using LMX See Section 6 2 PARALLEL END PARALLEL and Section 6 6 DO END DO for more information on how to use the REDUCTION clause on a parallel DO loop 6 4 MASTER END MASTER The OpenMP END MASTER directive uses the following syntax SOMP MASTER lt Fortran code in body of MASTER section gt SOMP END MASTER In a parallel region of code there may be a sub region of code that should execute only on the master thread Instead of ending the parallel region before this subregion and then starting it up again after this subregion the MASTER END MASTER directive pair let you conveniently designate code that executes on the master thread and is skipped by the other threads There is no implied barrier on entry to or exit from a MASTER END MASTER section of code Nested master sections are ignored Branching into or out of a master section is not supported PROGRAM MASTER _USE INTEGER A 0 1 INTEGER omp_get_thread_num A 1 SOMP PARALLEL A omp_get_thread_num omp_get_thread_num SOMP MASTER PRINT YOU SHOULD ONLY SEE THIS ONCE SOMP END MASTER SOMP END PARALLEL PRINT A O A O A 1 A 1 END 108 OpenMP Directives for Fortran 6 5 SINGLE END SINGLE The OpenMP SINGLE END SINGLE directive uses the following syntax SOMP SINGLE Clauses lt Fortran code in body of SINGLE processor section gt SOMP END SI
183. mmand Line Options The chapters that follow provide more detailed information on other M lt pgflag gt options that control specific optimizations including function inlining Explicit parallelization through the use of OpenMP directives or pragmas is invoked using the mp option described in detail in Chapter 6 OpenMP Directives for Fortran 3 3 Local and Global Optimization using O Using the PGI compiler commands with the Olevel option you can specify any of the following optimization levels the capital O is for Optimize 00 level zero specifies no optimization A basic block is generated for each language statement Sal level one specifies local optimization Scheduling of basic blocks is performed Register allocation is performed 26 Optimization amp Parallelization 02 level two specifies global optimization This level performs all level one local optimization as well as level two global optimization 03 level three specifies aggressive global optimization This level performs all level one and level two optimizations and enables more aggressive hoisting and scalar replacement optimizations that may or may not be profitable Level zero optimization specifies no optimization O0 At this level the compiler generates a basic block for each statement This level is useful for the initial execution of a program Performance will almost always be slowest using this optimization level Level zero is useful
184. more advanced self guided tutorial on how to parallelize the NAS FT fast Fourier transform benchmark using OpenMP directives You can retrieve it using a web browser and unpack it using the following commands within a shell command window gunzip fftpde tar gz tar xvf fftpde tar d i Follow the instructions in the README file to work through the tutorial 6 1 Parallelization Directives Parallelization directives are comments in a program that are interpreted by the PGI Fortran compilers when the option mp is specified on the command line The form of a parallelization directive is sentinel directive _name clauses With the exception of the SGI compatible DOACROSS directive the sentinel must be OMP C OMP or OMP must start in column 1 one and must appear as a single word without embedded white space The sentinel marking a DOACROSS directive is C Standard Fortran syntax restrictions line length case insensitivity etc apply to the directive line Initial directive lines must have a space or zero in column six and continuation directive lines must have a character other than space or zero in column six Continuation lines for CSDOACROSS directives are specified using the C amp sentinel 103 The order in which clauses appear in the parallelization directives is not significant Commas separate clauses within the directives but commas are not allowed between the directive name and the first clause Clauses on direct
185. n a binary constant is illegal S030 Explicit shape must be specified for 178 Messages 031 Illegal data type length specifier for The data type length specifier e g 4 in INTEGER 4 is not a constant expression that is a member of the set of allowed values for this particular data type W032 Data type length specifier not allowed for The data type length specifier e g 4 in INTEGER 4 is not allowed in the given syntax e g DIMENSION A 10 4 033 Illegal use of constant A constant was used in an illegal context such as on the left side of an assignment statement or as the target of a data initialization statement 034 Syntax error at or near I035 Predefined intrinsic loses intrinsic property An intrinsic name was used in a manner inconsistent with the language definition for that intrinsic The compiler based on the context will treat the name as a variable or an external function 036 Illegal implicit character range First character must alphabetically precede second 037 Contradictory data type specified for The indicated identifier appears in more than one type specification statement and different data types are specified for it S038 Symbol has not been explicitly declared The indicated identifier must be declared in a type statement this is required when the IMPLICIT NONE statement occurs in the subprogram W039 Symbol appears illegally in a SAVE statement An identifier a
186. n addition the default is to not parallelize innermost loops since these often by definition are vectorizable using SSE instructions and it is seldom profitable to both vectorize and parallelize the same loop especially on multi core processors Compiler switches and directives are available to let you override most of these restrictions on auto parallelization 3 6 1 Auto parallelization Sub options The parallelizer performs various operations that can be controlled by arguments to the Mconcur command line option The following sections describe these arguments that affect the operation of the vectorizer In addition these vectorizer operations can be controlled from within code using directives and pragmas For details on the use of directives and pragmas refer to Chapter 7 Optimization Directives By default Mconcur without any sub options is equivalent to Mconcur dist block This enables parallelization of loops with blocked iteration allocation across the available threads of execution These defaults may vary depending on the target system 3 6 1 1 Altcode Option The option Mconcur altcode instructs the parallelizer to generate alternate serial code for parallelized loops If altcode is specified without arguments the parallelizer determines an appropriate cutoff length and generates serial code to be executed whenever the loop count is less than or equal to that length If altcode n is specified the serial altcode i
187. n level OU or select g to perform minimal optimization At this level you will be able to debug your program easily and isolate any coding errors exposed during porting to x86 or x64 platforms If you want to get started quickly with optimization a good set of options to use with any of the PGI compilers is fastsse Mipa fast For example pgf95 fastsse Mipa fast prog f In PVF similar options may be accessed using the Optimization property in the Fortran Optimization property page For all of the PGI Fortran compilers this option will generally produce code that is well optimized without the possibility of significant slowdowns due to pathological cases The fastsse option is an aggregate option that includes a number of individual PGI compiler options which PGI compiler options are included depends on the target for which compilation is performed The Mipa fast option invokes interprocedural analysis including several IPA suboptions By experimenting with individual compiler options on a file by file basis further significant performance gains can sometimes be realized However individual optimizations can sometimes cause slowdowns depending on coding style and must be used carefully to ensure performance improvements result In addition to fastsse the optimization flags most likely to further improve performance are O3 Mpfi Mpfo Minline and on targets with multiple processors Mconcur In PVF t
188. n of code This is often due to a shared variable that is written and then read again The CRITICAL END CRITICAL directive pair defines a subsection of code within a parallel region referred to as a critical section which will be executed one thread at a time The optional name argument identifies the critical section The first thread to arrive at a critical section will be the first to execute the code within the section The second thread to arrive will not begin execution of statements in the critical section until the first thread has exited the critical section Likewise each of the remaining threads will wait its turn to execute the statements in the critical section Critical sections cannot be nested and any such specifications are ignored Branching into or out of a critical section is illegal If a name argument appears on a CRITICAL directive the same name must appear on the END CRITICAL directive PROGRAM CRITICAL USE REAL A 100 100 MX LMX INTEGER I J MX 1 0 LMX 1 0 CALL RANDOM SEED CALL RANDOM NUMBER A SOMP PARALLEL PRIVATE I FIRSTPRIVATE LMX SOMP DO OpenMP Directives for Fortran 107 DO J 1 100 DO I 1 100 LMX MAX A I J LMX ENDDO ENDDO SOMP CRITICAL MX MAX MX LMX SOMP END CRITICAL SOMP END PARALLEL PRINT MAX VALUE OF A IS MX END Note that this program could also be implemented without the critical region by declaring MX as a reduction variable and perfor
189. n particular if file A contains a USE statement referring to a Fortran module defined in file B file B must be compiled successfully before file A will compile To do this PVF begins compiling files in alphabetical order If a compile fails due to an unsatisfied module dependency the offending file is placed back on the build queue and a message is printed to the Output Window but not the Error List In a correct Fortran program all dependencies will eventually be met and the project will be built successfully Otherwise errors will be printed to the Error List as usual Subsequent builds use the build dependency information generated during the course of the initial build 1 8 1 Order of PVF Build Operations In the default PVF project build the build operations are executed in the following order Pre Build Event Custom Build Steps for Files Build Resources Compile Fortran Files to Objects using the PGI Fortran compiler Pre Link Event Build Output Files using linker or librarian Custom Build Step for Project Post Link Event Getting Started with PVF 5 1 9 Custom Build Step and Build Events PVF provides default build rules for Fortran files and Resource files Other files are ignored unless a build action is specified using a Custom Build Step or a Build Event Build Events allow definition of a specific command to be executed at a predetermined point during the project build Build events can be
190. n particular the format of unformatted data files produced by PGI Fortran compilers is identical to the format used on Sun and SGI workstations that allows you to read and write unformatted Fortran data files produced on those platforms from a program compiled for an x86 or x64 platform using the byteswapio option Default The compiler does not byte swap data on input output Usage The following command line requests byte swapping are performed on input output pgf95 byteswapio myprog f C Enables array bounds checking If an array is an assumed size array the bounds checking only applies to the lower bound If an array bounds violation occurs during execution an error message describing the error is printed and the program terminates The text of the error message includes the name of the array the location where the error occurred the source file and the line number in the source and information about the out of bounds subscript its value its lower and upper bounds and its dimension Default The compiler does not enable array bounds checking Usage In this example the compiler instruments the executable produced from myprog f to perform array bounds checking at runtime pgf95 C myprog f Cross reference Mbounds C Stops after the assembling phase Use the c option to halt the compilation process after the assembling phase and write the object code to the file filename o where the input file is filena
191. n values are returned in rax Floating point return values are returned in xmm0 Additional registers with assigned roles in the standard calling sequence rsp rbp The stack pointer holds the limit of the current stack frame which is the address of the stack s bottom most valid word The stack pointer should point to a 16 byte aligned area unless in the prolog or a leaf function The frame pointer if used can provide a way to reference the previous frame on the stack Details are implementation dependent A function must preserve this register value for its caller MXCSR The flags register MXCSR contains the system flags such as the direction x87 flag and the carry flag The six status flags MXCSR 0 5 are volatile the remainder of the register is nonvolatile Floating Point Control Word FPCSR The control word contains the floating point flags such as the rounding mode and exception masking This register is initialized at process initialization time and its value must be preserved Signals can interrupt processes Functions called during signal handling have no unusual restriction on their use of registers Moreover if a signal handling function returns the process resumes its original execution path with registers restored to their original values Thus programs and compilers may freely use all registers without danger of signal handlers changing their values A 2 2 Function Return Values Functions Returning
192. ne indicates the directive applies to the next subprogram l loop indicates the directive applies to the next loop but not to any loop contained within the loop body Loop scoped directives are only applied to DO loops blank indicates that the default scope for the directive is applied The body of the directive may immediately follow the scope indicator Alternatively any number of blanks may precede the name of the directive Any names in the body of the directive including the directive name may not contain embedded blanks Blanks may surround any special characters such as a comma or an equal sign The directive name including the directive prefix may contain upper or lower case letters case is not significant Case is significant for any variable names that appear in the body of the directive if the command line option Mupcase is selected For compatibility with other vendors directives the prefix cpgi may be substituted with cdir or cvd 121 7 2 Fortran Directive Summary The next table summarizes the supported Fortran directives The scope entry indicates the allowed scope indicators for each directive the default scope is surrounded by parentheses The system field indicates the target system type for which the pragma applies Many of the directives can be preceded by NO The default entry in the table indicates the default of the directive n a appears if a default does not apply The name of a directive may also be
193. nes a suitable value of n for each loop cpgi noaltcodeThis directive sets the loop count thresholds for parallelization of all innermost loops to 0 and disables alternate code generation for vectorized loops Optimization Directives assoc noassoc This directive toggles the effects of the Mvect noassoc command line option an Optimization M control By default when scalar reductions are present the vectorizer may change the order of operations so that it can generate better code e g dot product Such transformations change the result of the computation due to roundoff error The noassoc directive disables these transformations This directive affects the compiler only when Mvect is enabled on the command line bounds nobounds This directive alters the effects of the Mbounds command line option This directive enables the checking of array bounds when subscripted array references are performed By default array bounds checking is not performed cncall nocncall Loops within the specified scope are considered for parallelization even if they contain calls to user defined subroutines or functions or if their loop counts do not exceed the usual thresholds A nocncall directive cancels the effect of a previous cncall concur noconcur This directive alters the effects of the Mconcur command line option The directive instructs the auto parallelizer to enable auto concurrentization of loops If concur is specified
194. ng each file If there are IPA optimized objects from a previous build the compilers will minimize the recompile time by reusing those objects if they are still valid They will still be valid if the IPA optimized object is newer than the original object file and the propagated IPA information for that file has not changed since it was optimized 42 Optimization amp Parallelization After each object file has been recompiled the regular linker is invoked to build the application with the IPA optimized object files The IPA optimized object files are saved in the same directory as the original object files for use in subsequent program builds 3 7 5 Building a Program with IPA Single Step By adding the Mipa command line switch several source files can be compiled and linked with interprocedural optimizations with one command pgf95 Mipa fast o filel exe filel f95 file2 95 file3 95 Just like compiling without Mipa the driver executes several steps to produce the assembly and object files to create the executable pgf95 Mipa fast S o filel s filel1 f95 as o filel obj filel s pgf95 Mipa fast S o file2 s file2 f 95 as o file2 obj file2 s pgf95 Mipa fast S o file3 s file3 f95 as o file3 obj file3 s pgf95 Mipa fast o filel exe filel obj file2 obj file3 obj d i d i dp dp oP d i d i In the last step an IPA linker is invoked to read all the IPA summary information and perform the interprocedural
195. nment Variables A 120 Optimization Directives cseseecccessseeeeneeeeeeeesseeeeeeeseeeeeeeneeeees 121 Adding Directives to Fortran eeeeecceeeeeeeeeeceeeeeeeeeaeeeeeeeeaeeeeeseaaeeeeneeaas 121 Fortran Directive Summary cccccceeseeceeeeeeeeeeeeeeeeeeeaeeseeeeeesaaeeteneeee 122 Scope of Directives and Command Line options s s s 128 IDEC directive extensions c cccccceeccceeeceeceeeeeeeeeeeseeeeeeeeeeaeessaeenneeeaaes 130 NK AER 131 Libraries and Environment Variables ssssssseeeeeeeeeeeeeeeeeeee 133 Creating and Using Dynamic Link Libraries on Windows n s 133 Using EIBSF arare E i e a E N ait ave eatinedi N 137 LAPACK the BLAS and FFTS eccccceececeeeeeeeeeeeeceeeeeeeeaaeseeeeeeetaeesennes 137 Environment Variables 0 00 eeccceeeeeseeceeeeenneeeeeeeeaeeeeeeeenaeeeeeeeeateeeesenaaes 138 Chapter 9 9 1 9 1 1 9 1 2 9 1 3 Chapter 10 Appendix A A 1 A 1 1 A 1 1 1 A 1 2 A 1 3 A 2 A 2 1 A 2 2 A 2 3 A 2 4 A 2 4 1 A 2 4 2 A 2 4 3 A 2 4 4 Appendix B B 1 B 2 B 3 B 3 1 B 3 2 B 4 B 4 1 B 4 2 vi Fortran Data Ty Pes Zeenen 141 Fonran Data Types esanera E A 141 Fortran SCalarse s sraa AE eene a e N TENE a EE athe hae 141 FORTRAN 77 Aggregate Data Type Extensions ccceeteeeeeeeeeees 144 Fortran 90 Aggregate Data Types Derived Types eccess 146 Inter lanQuage Calling cccccseeceseeeeeesseeeeeeeeeeeeeenseeeeeeneeeeeeees 147 Run time Environment
196. ns that return no value also called procedures or void functions put no particular value in any register e A call instruction pushes the address of the next instruction the return address onto the stack The return instruction pops the address off the stack and effectively continues execution at the next instruction after the call instruction A function that returns a scalar or no value must preserve the caller s registers as described above Additionally the called function must remove the return address from the stack leaving the stack pointer esp with the value it had before the call instruction was executed Functions Returning Structures or Unions If a function returns a structure or union then the caller provides space for the return value and places its address on the stack as argument word zero In effect this address becomes a hidden first argument A function that returns a structure or union also sets eax to the value of the original address of the caller s area before it returns Thus when the caller receives control again the address of the returned object resides in register eax and can be used to access the object Both the calling and the called functions must cooperate to pass the return value successfully e The calling function must supply space for the return value and pass its address in the stack frame e The called function must use the address from the frame and copy the return value to the object so supplie
197. nsic list The SECTIONS END SECTIONS directives define a non iterative work sharing construct within a parallel region Each section is executed by a single processor If there are more processors than sections some processors will have no work and will jump to the implied barrier at the end of the construct If there are more sections than processors one or more processors will execute more than one section A SECTION directive may only appear within the lexical extent of the enclosing SECTIONS END SECTIONS directives In addition the code within the SECTIONS END SECTIONS directives must be a structured block and the code in each SECTION must be a structured block The available clauses are as defined in Section 6 2 PARALLEL END PARALLEL and Section 6 6 DO END DO 6 13 PARALLEL SECTIONS The OpenMP PARALLEL SECTIONS END SECTIONS directive pair uses the following syntax Syntax SOMP PARALLEL SECTIONS CLAUSES SOMP SECTION lt Fortran code block executed by processor i gt SOMP SECTION lt Fortran code block executed by processor j gt SOMP END SECTIONS NOWAIT Clauses PRIVATE list SHARED list DEFAULT PRIVATE SHARED NONE FIRSTPRIVATE list LASTPRIVATE list OpenMP Directives for Fortran 115 REDUCTION operator intrinsic list COPYIN list IF scalar_logical_ expression NUM_THREADS scalar_integer_expression The PARALLEL SECTIONS END SECTIONS di
198. nt is a scalar variable W369 Dummy argument has different rank than actual argument The actual argument is an array or array valued expression with a different rank than the dummy argument W370 Dummy argument has different shape than actual argument The actual argument is an array or array valued expression with a different shape than the dummy argument this may require copying the actual argument into sequential storage W371 Dummy argument is INTENT IN but may be modified The dummy argument was declared as INTENT IN but analysis has found that the argument may be modified the INTENT IN declaration should be changed W372 Cannot propagate alignment from to The most common cause is when passing an array with an inherited alignment to a dummy argument with non inherited alignment I373 Cannot propagate distribution format from to The most common cause is when passing an array with a transcriptive distribution format to a dummy argument with prescriptive or descriptive distribution format I374 Cannot propagate distribution target from to The most common cause is when passing an array with a transcriptive distribution target to a dummy argument with prescriptive or descriptive distribution target I375 Distribution format mismatch between and Usually this arises when the actual and dummy arguments are distributed in different dimensions I376 Alignment stride mismatch between and This may aris
199. nym for unit 5 on input and unit 6 on output the compiler treats lines containing D in column 1 as executable statements ignoring the D the compiler does not treat lines containing D in column as executable statements does not ignore the D 71 Mextend Mfixed Mfree Miomutex Mnoiomutex Monetrip Mnoonetrip Msave Mnosave Mstandard Munixlogical Mnounixlogical Mupcase 72 char specifies the character to which the compiler maps the dollar sign The compiler allows the dollar sign in names with Mextend the compiler accepts 132 column source code otherwise it accepts 72 column code with Mfixed the compiler assumes input source files are in FORTRAN 77 style fixed form format with Mfree the compiler assumes the input source files are in Fortran 90 95 freeform format the compiler generates critical section calls around Fortran I O statements the compiler does not generate critical section calls around Fortran I O statements the compiler forces each DO loop to execute at least once the compiler does not force each DO loop to execute at least once This option is useful for programs written for earlier versions of Fortran the compiler assumes that all local variables are subject to the SAVE statement Note that this may allow older Fortran programs to run but it can greatly reduce performance the compiler does not assume that all local variables
200. o Mvect assoc cachesize 262144 This enables the options for nested loop transformation and various other vectorizer options These defaults may vary depending on the target system Optimization amp Parallelization 31 3 5 1 1 Assoc Option The option Mvect assoc instructs the vectorizer to perform associativity conversions that can change the results of a computation due to roundoff error Mvect noassoc disables this option For example a typical optimization is to change one arithmetic operation to another arithmetic operation that is mathematically correct but can be computationally different and generate faster code This option is provided to enable or disable this transformation since roundoff error for such associativity conversions may produce unacceptable results 3 5 1 2 Cachesize Option The option Mvect cachesize n instructs the vectorizer to tile nested loop operations assuming a data cache size of n bytes By default the vectorizer attempts to tile nested loop operations such as matrix multiply using multi dimensional strip mining techniques to maximize re use of items in the data cache 3 5 1 3 SSE Option The option Mvect sse instructs the vectorizer to automatically generate packed SSE SSE2 streaming SIMD extensions and prefetch instructions when vectorizable loops are encountered SSE instructions first introduced on Pentium III and AthlonXP processors operate on single precision floating point d
201. o take effect To set this option in PVF use the Fortran Floating Point Options Flush Denormalized Results to Zero property Do not set SSE flush to zero mode generate underflows This option must be set for the main program to take effect Align functions on 32 byte boundaries Enable support for 64 bit indexing and single static data objects larger than 2GB in size This option is default in the presence of mcmodel medium Can be used separately together with the default small memory model for certain 64 bit applications that manage their own memory space Disable support for 64 bit indexing and single static data objects larger than 2GB in size When placed after mcmodel medium on the command line disables use of 64 bit indexing for applications that have no single data object larger than 2GB instructs the compiler not to include the object file that calls the Fortran main program as part of the link step This option is useful for linking programs in which the main program is written in C C and one or more subroutines are written in Fortran pgf77 pgf95 and pghpf only instructs the compiler to generate nontemporal move and prefetch instructions even in cases where the compiler cannot determine statically at compile time that these instructions will be beneficial Set profile options option can be any of the following func perform PGI style function level profiling lines perform PGI style line level profiling To
202. ocess for a specific routine or a specific program loop For a complete alphabetical listing and a description of all the Fortran directives refer to Chapter 6 OpenMP Directives for Fortran and Chapter 7 Optimization Directives 2 3 Filename Conventions The PGI compilers use the filenames that you specify on the command line to find and to create input and output files This section describes the input and output filename conventions for the phases of the compilation process 2 3 1 Input Files You can specify assembly language files preprocessed source files Fortran C C source files object files and libraries as inputs on the command line The compiler driver determines the type of each input file by examining the filename extensions The drivers use the following conventions filename f indicates a Fortran source file filename F indicates a Fortran source file that can contain macros and preprocessor directives to be preprocessed Getting Started with the Command Line Compilers 17 Dlename POR indicates a Fortran source file that can contain macros and preprocessor directives to be preprocessed filename F95 indicates a Fortran 90 95 source file that can contain macros and preprocessor directives to be preprocessed filename f90 indicates a Fortran 90 95 source file that is in freeform format filename f95 indicates a Fortran 90 95 source file that is in freeform format filename s indicates an assembly lan
203. ograms that manage graphical user interface components using Fortran code are referred to as Windows Applications within PVF A PVF Windows Application can be created by selecting Windows Application in the PVF New Project dialog or by changing the Configuration Type property to Windows Application in the PVF General property page PVF Windows Applications are characterized by the lack of a PROGRAM statement Instead Windows Applications must provide a WinMain function like the following Example 1 1 PVF WinMain for x64 integer 4 function WinMain hInstance amp hPrevinstance lpszCmdLine nCmdShow integer 8 hInstance integer 8 hPrevInstance integer 8 lpszCmdLine integer 4 nCmdShow Note that since hInstance hPrevInstance and lpszCmdLine are all x64 pointers they must be 8 byte integers If this were a 32 bit program these would be 4 byte integers nCmdShow is an integer specifying how the window is to be shown look up WinMain in the Microsoft Platform SDK documentation for additional details Getting Started with PVF The PVF Windows Application project type provides a template for WinMain The PVF sample program samples win32api menu_dialog is a small application using WinMain 1 17 5 1 Menus Dialog Boxes and Resources The use of resources in PVF is similar to their use in Visual C The resource files that control menus and dialog boxes have the file extension rc These files are processed with the Microsoft
204. ommand Line Options 59 pgf95 myprog f lmylib M lt pgflag gt Selects options for code generation The options are divided into the following categories Code generation Environment Inlining Fortran Language Controls C C Language Controls Optimization Miscellaneous The following table lists and briefly describes the options alphabetically and includes a field showing the category 60 Command Line Options Table 4 2 M Options Summary declared pgf77 pgf95 and pghpf only pgflag Description Category anno annotate the assembly code with source code Miscellaneous no autoinline C C when a function is declared with the inline Inlining keyword inline it at O2 and above no backslash determines how the backslash character is treated Fortran Language in quoted strings pgf77 pgf95 and pghpf only no bounds specifies whether array bounds checking is Miscellaneous enabled or disabled byteswapio Swap byte order big endian to little endian or Miscellaneous vice versa during I O of Fortran unformatted data cache_align where possible align data objects of size greater Optimization than or equal to 16 bytes on cache line bound aries chkfpstk check for internal consistency of the x87 FP stack Miscellaneous in the prologue of a function and after returning from a function or subroutine call tp px p5 p6 piii targets only chkptr check for NULL
205. ompiler does not perform an initial extract pass The compiler selects functions to inline from the specified inline library If you also specify a size or function name all functions in the inline library meeting the selection criteria are selected for inline expansion at points in the source text where they are called If you do not specify a function name or a size limitation for the Minline option the compiler inlines every function in the inline library that matches a function in the source text In the following example the compiler inlines the function proc from the inline library lib il and writes the executable code in the default output file a out pgf95 Minline name proc lib lib il myprog f The following command line is equivalent to the line above the only difference in this example is that the name and lib inline keywords are not used The keywords are provided so you can avoid name conflicts if you use an inline library name that does not contain a period Otherwise without the keywords a period lets the compiler know that the file on the command line is an inline library pgf95 Minline proc lib il myprog f 98 Function Inlining 5 2 Creating an Inline Library You can create or update an inline library using the Mextract command line option If you do not specify a selection criteria along with the Mextract option the compiler attempts to extract all subprograms When you use the Mextract option only the
206. on Unrolling Vectorization and Parallelization The performance of certain classes of loops may be improved through vectorization or unrolling options Vectorization transforms loops to improve memory access performance and make use of packed SSE instructions which perform the same operation on multiple data items concurrently Unrolling replicates the body of loops to reduce loop branching overhead and provide better opportunities for local optimization vectorization and scheduling of instructions Performance for loops on systems with multiple processors may also improve using the parallelization features of the PGI compilers Inter Procedural Analysis and Optimization IPA Interprocedural analysis allows use of information across function call boundaries to perform optimizations that would otherwise be unavailable For example if the actual argument to a function is in fact a constant in the caller it may be possible to propagate that constant into the callee and perform optimizations that are not valid if the dummy argument is treated as a variable A wide range of optimizations are enabled or improved by using IPA including but not limited to data alignment optimizations argument removal constant propagation pointer disambiguation pure function detection F90 F95 array shape propagation data placement vestigial function removal automatic function inlining inlining of functions from pre compiled libraries and interprocedural optimizati
207. on of functions from pre compiled libraries Function Inlining This optimization allows a call to a function to be replaced by a copy of the body of that function This optimization will sometimes speed up execution by eliminating the function call and return overhead Function inlining may also create opportunities for other types of optimization Function inlining is not always beneficial When used improperly it may increase code size and generate less efficient code Profile Feedback Optimization PFO Profile feedback optimization makes use of information from a trace file produced by specially instrumented executables which capture and save information on branch frequency function and subroutine call frequency semi invariant values loop index ranges and other input data dependent 24 Optimization amp Parallelization information that can only be collected dynamically during execution of a program By definition use of profile feedback optimization is a two phase process compilation and execution of a specially instrumented executable followed by a subsequent compilation which reads a trace file generated during the first phase and uses the information in the trace file to guide compiler optimizations 3 2 Getting Started with Optimizations Your first concern should be getting your program to execute and produce correct results To get your program running start by compiling and linking without optimization Use the optimizatio
208. onal The available clauses are as defined in Section 6 2 PARALLEL END PARALLEL and Section 6 6 DO END DO 6 11 PARALLEL WORKSHARE The OpenMP PARALLEL WORKSHARE directive uses the following syntax Syntax SOMP PARALLEL WORKSHARE CLAUSES lt Fortran structured block to be executed in parallel gt SOMP END PARALLEL WORKSHARE Clauses PRIVATE list SHARED list DEFAULT PRIVATE SHARED NONE FIRSTPRIVATE list LASTPRIVATE list REDUCTION operator intrinsic list COPYIN list IF scalar_logical_ expression NUM_THREADS scalar_integer_expression SCHEDULE type chunk ORDERED The semantics of the PARALLEL WORKSHARE directive are identical to those of a parallel region containing a single WORKSHARE construct Note that the END PARALLEL WORKSHARE directive is optional and that NOWAIT may not be specified on an END PARALLEL WORKSHARE directive The available clauses are as defined in Section 6 2 PARALLEL END PARALLEL 6 12 SECTIONS END SECTIONS The OpenMP SECTIONS END SECTIONS directive pair uses the following syntax Syntax 114 OpenMP Directives for Fortran SOMP SECTIONS Clauses SOMP SECTION lt Fortran code block executed by processor i gt SOMP SECTION lt Fortran code block executed by processor j gt SOMP END SECTIONS NOWAIT Clauses PRIVATE list FIRSTPRIVATE list LASTPRIVATE list REDUCTION operator intri
209. ons for both the Visual Studio integrated development environment as well as command level compilation and general information about PGI s implementation of the Fortran language This guide does not teach the Fortran programming language Audience Description This guide is intended for scientists and engineers using PGI Visual Fortran To fully understand this guide you should be aware of the role of high level languages e g Fortran in the software development process and should have some level of understanding of programming PGI Visual Fortran is available on a variety of x86 or x64 hardware platforms and variants of the Windows operating system You need to be familiar with the basic commands available on your system Finally your system needs to be running a properly installed and configured version of PVF For information on installing PVF refer to the Release and Installation Notes included with your software Compatibility and Conformance to Standards For further information refer to the following American National Standard Programming Language FORTRAN ANSI X3 1978 1978 e ISO IEC 1539 1991 Information technology Programming Languages Fortran Geneva 1991 Fortran 90 e ISO IEC 1539 1997 Information technology Programming Languages Fortran Geneva 1997 Fortran 95 e Fortran 95 Handbook Complete ISO ANSI Reference Adams et al The MIT Press Cambridge Mass 1997 OpenMP Application
210. oops That is the directive only applies to the following loop In this example the directive turns off vector transformations for the top level loop If the outer loop were a timing loop this would be a practical use for a loop scoped directive Optimization Directives 129 7 4 DEC directive extensions These extensions are only enabled on Windows platforms Syntax ATTRIBUTES Clause DECS ATTRIBUTES lt attr option gt where lt attr option gt is one of ALIAS alias_name routine_name Specifies an alternative name with which to resolve routine_name C Same as STDCALL on Win64 DLLEXPORT name Specifies that name is being exported to other applications or DLL s DLLIMPORT name Specifies that name is being imported from other applications or DLL s REFERENCE name Specifies that the argument name is being passed by reference Often this attribute is used in conjuction with STDCALL where STDCALL refers to an entire routine then individual arguments are modified with REFERENCE STDCALL routine_name Specifies that routine routine_name will have its arguments passed by value When a routine marked STDCALL is called arguments except arrays and characters will be sent by value The standard F90 F95 calling convention is by reference VALUE name Specifies that the argument name is being passed by value Often used to specify that a particular argument is being passed by value Loop Distribution Direct
211. ops the loops are short and the structure of the code is regular The PGI compilers perform many different types of global optimizations including but not limited to e Branch to branch elimination e Constant propagation Copy propagation Dead store elimination Global register allocation Invariant code motion e Induction variable elimination Optimization amp Parallelization 27 You select the optimization level on the command line For example level two optimization results in global optimization as shown below pgf95 O02 prog f Specifying O on the command line without a level designation is equivalent to O2 The default optimization level changes depending on which options you select on the command line For example when you select the g debugging option the default optimization level is set to level zero O0 However you can override this default by placing Olevel option after g on the command line if you need to debug optimized code Refer to Section 2 8 Default Optimization Levels for a description of the default levels As noted above the fast option includes O2 on all x86 and x64 targets If you wish to override this with O3 while maintaining all other elements of fast simply compile as follows pgf95 fast 03 prog f Note Most modern x86 processors support SSE instructions so using the fastsse option instead of fast is recommended for those processors On
212. option enabled you cannot perform a traceback on the generated code and you cannot access local variables 77 Mnoi4 Mpfi To set this option in PVF use the Fortran Optimization Use Frame Pointer property the compiler treats INTEGER variables as INTEGER 2 generate profile feedback instrumentation this includes extra code to collect run time statistics and dump them to a trace file for use in a subsequent compilation Mpfi must also appear when the program is linked When the resulting program is executed a profile feedback trace file pgfi out is generated in the current working directory see Mpfo Note compiling and linking with Mpfi adds significant runtime overhead to almost any executable you should use executables compiled with Mpfi only for execution of training runs Mpfo enable profile feedback optimizations requires the presence of a pgfi out profile feedback trace file in the current working directory See Mpfi Mprefetch option option enables generation of prefetch instructions on processors where they Mnoprefetch Mr8 Mnors Mr8sintrinsics 78 are supported Possible values for option include d m set the fetch ahead distance for prefetch instructions to m cache lines n p set the maximum number of prefetch instructions to generate for a given loop to p nta use the prefetchnta instruction plain use the prefetch instruction default t0 use the prefetchtO
213. orking directory F004 Generic message for file errors F005 Unable to open temporary file Compiler uses directory usr tmp or tmp in which to create temporary files If neither of these directories is available on the node on which the compiler is being used this error will occur s006 Input file empty Source input file does not contain any Fortran statements other than comments or compiler directives F007 Subprogram too large to compile at this optimization level Internal compiler data structure overflow working storage exhausted or some other non recoverable problem related to the size of the subprogram If this error occurs at opt 2 reducing the opt level to 1 may work around the problem Moving the subprogram being compiled to its own source file may eliminate the problem If this error occurs while compiling a subprogram of fewer than 2000 statements it should be reported to the compiler maintenance group as a possible compiler problem F008 Error limit exceeded The compiler gives up because too many severe errors were issued the error limit can be reset on the command line F009 Unable to open assembly file 176 Messages Probably user does not have write permission for the current working directory F010 File write error occurred Probably file system is full 011 Unrecognized command line switch Refer to PDS reference document for list of allowed compiler switches 012 Value required
214. ormation inline instructs the compiler to display information about extracted or inlined functions This option is not useful without either the Mextract or Minline option ipa instructs the compiler to display information about interprocedural optimizations loop instructs the compiler to display information about loops such as information on vectorization opt instructs the compiler to display information about optimization mp instructs the compiler to display information about parallelization time instructs the compiler to display compilation Statistics unroll instructs the compiler to display information about loop unrolling Mneginfo option option neginfo instructs the compiler to produce information on standard Command Line Options error where option is one of the following all instructs the compiler to produce all available information on why various optimizations are not performed 83 Minform level Mkeepasm Milist Mnolist Mmaked11 Mnoopenmp Mnosgimp 84 concur instructs the compiler to produce all available information on why loops are not automatically parallelized In particular if a loop is not parallelized due to potential data dependence the variable s that cause the potential dependence will be listed in the Mneginfo messages loop instructs the compiler to produce information on why memory hierarchy optimizations on loops are not performed inst
215. ormation increases the size of the object module If you specify the g option on the command line the compiler sets the optimization level to O0 zero unless you specify the O option For more information on the interaction between the g and O options see the O entry Symbolic debugging may give confusing results if an optimization level other than zero is selected Default The compiler does not put debugging information into the object module Usage In the following example the object file a out contains symbolic debugging information pgf95 g myprog f 56 Command Line Options To set this option in PVF use the Fortran General Debug Information Format property gopt Use of g alters how optimized code is generated in ways that are intended to enable or improve debugging of optimized code The gopt option instructs the compiler to include symbolic debugging information in the object file and to generate optimized code identical to that generated when g is not specified Default The compiler does not put debugging information into the object module Usage In the following example the object file a out contains symbolic debugging information pgf95 gopt myprog f To set this option in PVF use the Fortran General Debug Information Format property I Adds a directory to the search path for files that are included using the INCLUDE statement or the preprocessor directive include Use the I option to a
216. ortran 109 SOMP DO Clauses lt Fortran DO loop to be executed in parallel gt SOMP END DO NOWAIT Clauses PRIVATE list FIRSTPRIVATE list LASTPRIVATE list REDUCTION operator intrinsic list SCHEDULE type chunk ORDERED The real purpose of supporting parallel execution is the distribution of work across the available threads You can explicitly manage work distribution with constructs such as IF omp_get_thread_num EQ 0 THEN ELSE l IF omp_get_thread_num EQ 1 THEN ENDIF However these constructs are not in the form of directives The DO END DO directive pair provides a convenient mechanism for the distribution of loop iterations across the available threads in a parallel region Items to note about clauses are Variables declared in a PRIVATE list are treated as private to each processor participating in parallel execution of the loop meaning that a separate copy of the variable exists on each processor Variables declared in a FIRSTPRIVATE list are PRIVATE and in addition are initialized from the original object existing before the construct Variables declared in a LASTPRIVATE list are PRIVATE and in addition the thread that executes the sequentially last iteration updates the version of the object that existed before the construct The REDUCTION clause is as described in Section 6 2 PARALLEL END PARALLEL The SCHEDULE clause is explained in the following section If ORDERED
217. oss all threads double precision function omp_get_wtick returns the resolution of omp_get_wtime in seconds as a DOUBLE PRECISION value subroutine omp_init lock integer var initializes a lock associated with the variable integer_var for use in subsequent calls to lock routines This initial state of integer_var is unlocked It is illegal to make a call to this routine if integer_var is already associated with a lock subroutine omp_destroy lock integer var disassociates a lock associated with the variable integer_var subroutine omp_set_lock integer var causes the calling thread to wait until the specified lock is available The thread gains ownership of the lock when it is available It is illegal to make a call to this routine if integer_var has not been associated with a lock subroutine omp_unset_lock integer_var causes the calling thread to release ownership of the lock associated with integer_var It is illegal to make a call to this routine if integer_var has not been associated with a lock logical function omp_test_lock integer var causes the calling thread to try to gain ownership of the lock associated with integer_var The function returns TRUE if the thread gains ownership of the lock and FALSE otherwise It is illegal to make a call to this routine if integer_var has not been associated with a lock OpenMP Directives for Fortran 119 6 19 Environment Variables OMP_NUM_THREADS specifies the number of
218. parallel region While this syntax is more convenient it should be noted that if multiple successive DO loops are to be parallelized it is more efficient to define a single enclosing parallel region and parallelize each loop using the OpenMP DO directive A variable declared PRIVATE or LOCAL to a CSDOACROSS loop is treated the same as a private variable in a parallel region or DO see above A variable declared SHARED or SHARE to a C DOACROSS loop is shared among the threads meaning that only 1 copy of the variable exists to be used and or modified by all of the threads This is equivalent to the default status of a variable that is not listed as PRIVATE in a parallel region or DO this same default status is used in C DOACROSS loops as well 6 10 PARALLEL DO The OpenMP PARALLEL DO directive uses the following syntax Syntax SOMP PARALLEL DO CLAUSES lt Fortran DO loop to be executed in parallel gt SOMP END PARALLEL DO Clauses PRIVATE list SHARED list DEFAULT PRIVATE SHARED NONE FIRSTPRIVATE list LASTPRIVATE list REDUCTION operator intrinsic list COPYIN list OpenMP Directives for Fortran 113 IF scalar_logical_ expression NUM_THREADS scalar_integer_expression SCHEDULE type chunk ORDERED The semantics of the PARALLEL DO directive are identical to those of a parallel region containing only a single parallel DO loop and directive Note that the END PARALLEL DO directive is opti
219. parallelize Examine this loop do I 1 N if x I gt 0 0 then t x T El Se sel Ser E endif enddo ae where each use of t within the loop is reached by a definition from the same iteration Here t is privatizable but the use of t outside the loop may yield incorrect results since the compiler may not be able to detect on which iteration of the parallelized loop t is last assigned The compiler detects the above cases Where a scalar is used after the loop but is not defined on every iteration of the loop parallelization will not occur When the programmer knows that the scalar is assigned on the last iteration of the loop the programmer may use a directive or pragma to let the compiler know the loop is safe to parallelize The Fortran directive which tells the compiler that for a given loop the last value computed for all scalars make it safe to parallelize the loop is cpgi l safe_lastval In addition a command line option Msafe_lastval provides this information for all loops within the routines being compiled essentially providing global scope 3 7 Inter Procedural Analysis and Optimization using Mipa The PGI Fortran compilers use interprocedural analysis IPA that results in minimal changes to makefiles and the standard edit build run application development cycle Other than adding Mipa to the command line or selecting the appropriate value for the PVF Fortran Optimization Optimization property no other c
220. ppearing in a SAVE statement must be a local variable or array 040 Illegal common variable Indicated identifier is a dummy variable is already in a common block or has previously been defined to be something other than a variable or array W041 Illegal use of dummy argument Messages 179 This error can occur in several situations It can occur if dummy arguments were specified on a PROGRAM statement It can also occur if a dummy argument name occurs ina DATA COMMON SAVE or EQUIVALENCE statement A program statement must have an empty argument list 042 is a duplicate dummy argument 043 Illegal attempt to redefine An attempt was made to define a symbol in a manner inconsistent with an earlier definition of the same symbol This can happen for a number of reasons The message attempts to indicate the situation that occurred intrinsic An attempt was made to redefine an intrinsic function A symbol that represents an intrinsic function may be redefined if that symbol has not been previously verified to be an intrinsic function For example the intrinsic sin can be defined to be an integer array If a symbol is verified to be an intrinsic function via the INTRINSIC statement or via an intrinsic function reference then it must be referred to as an intrinsic function for the remainder of the program unit symbol An attempt was made to redefine a symbol that was previously defined An example of this is to declare a symbol
221. pped common blocks were optimized by interprocedural analysis 202 Messages I321 IPA routine common blocks not optimized This many mapped common blocks were not optimized by interprocedural analysis either because they were declared differently in different routines or they did not appear in the main program I322 IPA analyzing main program Interprocedural analysis is building the call graph and propagating information with the named main program I323 IPA collecting information for Interprocedural analysis is saving information for the current subprogram for subsequent analysis and propagation W324 IPA file appears to be out of date W325 IPA file is for wrong subprogram W326 Unable to open file to propagate IPA information to I327 IPA subprograms analyzed I328 IPA dummy arguments replaced by constants I329 IPA INTENT IN dummy arguments should be INTENT INOUT I330 IPA dummy arguments changed to INTENT IN I331 IPA inherited array alignments replaced I332 IPA transcriptive distribution formats replaced Messages 203 1333 1334 I335 1336 1337 1338 339 340 341 342 343 344 IPA IPA IPA IPA IPA IPA transcriptive distribution targets replaced descriptive prescriptive array alignments verified descriptive prescriptive distribution formats verified descriptive prescriptive distribution targets veri
222. propriate target name win64 To use these libraries simply link them in using the l option when linking your main program pgf95 myprog f lblas llapack Highly optimized assembly coded versions of the BLAS and certain FFT routines may be available for your platform In some cases these are shipped with the PGI compilers See the current release notes for the PGI compilers you are using to determine if these optimized libraries exist where they can be downloaded if necessary and how to incorporate them into your installation as the default Libraries and Environment Variables 137 8 4 Environment Variables Several environment variables can be used to alter the default behavior of the PGI compilers and the executables which they generate Many of these environment variables are documented in context in other sections of the PGI User s Guide They are gathered here for easy reference Specifically excluded are environment variables specific to OpenMP which are used to control the behavior of OpenMP programs See section 5 17 Environment Variables for a list and description of environment variables that affect the execution of Fortran OpenMP programs Also excluded are environment variables that control the behavior of the PGDBG debugger or PGPROF profiler See the PGI Tools Guide for a description of environment variables that affect these tools FORTRAN_OPT If this variable exists and contains the value vaxio the record length in
223. ps that are both parallelized and vectorized for SSE This can improve performance in program units that include many such loops It can result in load balancing problems that significantly decrease performance in program units with relatively short loops that contain a large amount of work in each iteration The numa suboption uses libnuma on systems where it is available Default The compiler ignores user inserted shared memory parallel programming directives and pragmas Usage The following command line requests processing of any shared memory directives present in myprog f pgf95 mp myprog f To set this option in PVF use the Fortran Language Process OpenMP Directives property Cross reference Mconcur and Mvect O lt level gt Invokes code optimization at the specified level 86 Command Line Options Syntax O level Where level is one of the following 0 creates a basic block for each statement Neither scheduling nor global optimization is done To specify this level supply a 0 zero argument to the O option 1 schedules within basic blocks and performs some register allocations but does no global optimization 2 performs all level 1 optimizations and also performs global scalar optimizations such as induction variable elimination and loop invariant movement 3 level three specifies aggressive global optimization This level performs all level one and level two optimizations and enables more
224. qual e A name clash exists e g a call to subroutine xyz in the extracted subprogram and a variable named xyz in the caller Function Inlining 101 102 Function Inlining Chapter6 OpenMP Directives for Fortran The PGF77 and PGF95 Fortran compilers support the OpenMP Fortran Application Program Interface The OpenMP shared memory parallel programming model is defined by a collection of compiler directives library routines and environment variables that can be used to specify shared memory parallelism in Fortran C and C programs The directives include a parallel region construct for writing coarse grain SPMD programs work sharing constructs which specify that DO loop iterations should be split among the available threads of execution and synchronization constructs The data environment is controlled using clauses on the directives or with additional directives Run time library routines are provided to query the parallel runtime environment for example to determine how many threads are participating in execution of a parallel region Finally environment variables are provided to control the execution behavior of parallel programs For more information on OpenMP see http www openmp org For an introduction to how to execute programs that use multiple processors along with some pointers to example code see Section 2 4 Parallel Programming Using the PGI Compilers The file ftp ftp pgroup com pub SMP fftpde tar gz contains a
225. r The specified release must be co installed with the default release and must have a release number greater than or equal to 4 1 the first release for which this functionality is supported Usage The following command line shows the output using the V option pgf95 V myprog f The following command line causes PGF95 to compile using the 5 2 release instead of the default pgcc V5 2 myprog c To set this option in PVF use the Fortran General Display Startup Banner property Cross reference Minfo v V Use the v option to display the invocations of the compiler assembler and linker These invocations are command lines created by the compiler driver from the files and the W options you specify on the compiler command line Default The compiler does not display individual phase invocations Cross reference Minfo V W Passes arguments to a specific phase Use the W option to specify options for the assembler compiler or linker Note A given PGI compiler command invokes the compiler driver which parses the command line and generates the appropriate commands for the compiler assembler and linker Syntax W 0lall option option Where 0 the number zero specifies the compiler a specifies the assembler 1 lowercase letter 1 specifies the linker Command Line Options 95 option is a string that is passed to and interpreted by the compiler assembler or linker Options separated by comm
226. r critical sections are generated Fortran Language no large_arrays enable support for 64 bit indexing and single static data objects of size larger than 2GB Code Generation Main into the DLL no lre Disable enable loop carried redundancy elimina Optimization tion keepasm instructs the compiler to keep the assembly file Miscellaneous nolist specifies whether the compiler creates a listing Miscellaneous file makedll Generate a dynamic link library DLL Miscellaneous no movnt disable force generation of non temporal moves Code Generation and prefetching neginfo instructs the compiler to produce information on Miscellaneous why certain optimizations are not performed noframe eliminates operations that set up a true stack Optimization frame pointer for functions nomain when the link step is called don t include the Code Generation object file that calls the Fortran main program noopenmp when used in combination with the mp option Miscellaneous causes the compiler to ignore OpenMP parallel ization directives or pragmas but still process SGI style parallelization directives or pragmas nopgdllmain do not link the module containing the default DII Miscellaneous Command Line Options 63 pgflag Description Category norpath On Linux do not add rpath paths to the link line Miscellaneous nosg
227. recision in a given program unit the main program must be compiled with the same pc option The command line option pc val lets the programmer set the compiler s precision preference Valid values for val are 32 single precision 64 double precision 80 extended precision Extended Precision Option Operations performed exclusively on the floating point stack using extended precision without storing into or loading from memory can cause problems with accumulated values within the extra 16 bits of extended precision values This can lead to answers when rounded that do not match expected results For example if the argument to sin is the result of previous calculations performed on the floating point stack then an 80 bit value used instead of a 64 bit value can result in slight discrepancies Results can even change sign due to the sin curve being too close to an x intercept value when evaluated To maintain consistency in this case you can assure that the compiler generates code that calls a function According to the x86 ABI a function call must push its arguments on the stack in this way memory is guaranteed to be accessed even if the argument is an actual constant Thus even if the called function simply performs the inline expansion using the function call as a wrapper to sin has the effect of trimming the argument precision down to the expected size Using the Mnobuiltin option on the command line for C accomplishes t
228. recommended that you check carefully whether particular program units or loops show improved performance when compiled with this option enabled In PVF this option the basic forms of this option are accessed using the Vectorization property in the Fortran Optimization property page For more advanced use of this option use the Fortran Command Line property page 3 5 1 Vectorization Sub options The vectorizer performs high level loop transformations on countable loops A loop is countable if the number of iterations is set only before loop execution and cannot be modified during loop execution Some of the vectorizer transformations can be controlled by arguments to the Mvect command line option The following sections describe the arguments that affect the operation of the vectorizer In addition some of these vectorizer operations can be controlled from within code using directives and pragmas For details on the use of directives and pragmas refer to Chapter 7 Optimization Directives The vectorizer performs the following operations e Loop interchange e Loop splitting e Loop fusion e Memory hierarchy cache tiling optimizations Generation of SSE instructions on processors where these are supported Generation of prefetch instructions on processors where these are supported Loop iteration peeling to maximize vector alignment e Alternate code generation By default Mvect without any sub options is equivalent t
229. rectives define a non iterative work sharing construct without the need to define an enclosing parallel region Each section is executed by a single processor If there are more processors than sections some processors will have no work and will jump to the implied barrier at the end of the construct If there are more sections than processors one or more processors will execute more than one section A SECTION directive may only appear within the lexical extent of the enclosing PARALLEL SECTIONS END SECTIONS directives In addition the code within the PARALLEL SECTIONS END SECTIONS directives must be a structured block and the code in each SECTION must be a structured block The available clauses are as defined in Section 6 2 PARALLEL END PARALLEL and Section 6 6 DO END DO 6 14 ORDERED The OpenMP ORDERED directive is supported using the following syntax SOMP ORDERED lt Fortran code block executed by processor gt SOMP END ORDERED The ORDERED directive can appear only in the dynamic extent of a DO or PARALLEL DO directive that includes the ORDERED clause The code block between the ORDERED END ORDERED directives is executed by only one thread at a time and in the order of the loop iterations This sequentializes the ordered code block while allowing parallel execution of statements outside the code block The following additional restrictions apply to the ORDERED directive The ORDERED code block mus
230. rectory The first variety using the dir keyword lets you supply a directory parameter that indicates the directory where the compiler driver is located Qoptionprog opt The second variety using the option keyword lets you supply the option opt to the program prog The prog parameter can be one of pgftn as or Id Qpathpathname 90 Command Line Options The third Q variety using the path keyword lets you supply an additional pathname to the search path for the compiler s required o files Qproducesourcetype The fourth Q variety using the produce keyword lets you choose a stop after location for the compilation based on the supplied sourcetype parameter Valid sourcetypes are i c s and o These indicate respectively stop after preprocessing compiling assembling or linking Usage The following examples show the different Q options pgf95 Qproduce s hello f pgf95 Qoption ld s hello f pgf95 Qpath home test hello f pgf95 Qdir home comp new hello f Cross reference p r4 and r8 Interpret DOUBLE PRECISION variables as REAL r4 or REAL variables as DOUBLE PRECISION r8 Usage pgf95 r4 myprog f Cross reference i2 i4 i8 nor8 rc Specifies the name of the driver startup configuration file If the file or pathname supplied is not a full pathname the path for the configuration file loaded is relative to the DRIVER path the path of the currently exec
231. reference e When doing Windows development one must sometimes provide callback functions for message processing dialog processing etc These routines are called by the Windows system when events are processed In order to provide the expected function signature for a callback function the user may need to use the STDCALL attribute directive 1DEC ATTRIBUTE STDCALL in the declaration See the PVF examples for more detail on how to implement callbacks 1 17 3 Portability Interfaces Unix Linux PVF also includes Fortran module interfaces to libraries supporting some standard C library and Unix Linux system call functionality These functions are provided by the DFLIB and DFPORT modules To utilize these modules add the appropriate USE statement USE DFLIB USE DFPORT 1 17 4 Data Types Because the Win32 API and Portability interfaces resolve to C Language libraries it is important to understand how the data types compare within the two languages Here is a table summarizing how C types correspond with Fortran types for some of the more common data types 12 Getting Started with PVF Table 1 3 Fortran Data Type Mappings C Win32 Data Type Fortran Data Type BOOL LOGICAL 4 BYTE BYTE CHAR CHARACTER SHORT WORD INTEGER 2 DWORD INT LONG INTEGER 4 LONG LONG INTEGER 8 FLOAT REAL 4 DOUBLE REAL 8 x86 Pointers INTEGER 4 x64 Pointers INTEGER 8 1 17 5 Graphical User Interfaces Pr
232. riables are declared in an OpenMP program Mcpp option option 82 run the PGI cpp like pre processor without execution of any subsequent compilation steps This option is useful for generating dependence information to be included in makefiles option is one or more of the following Note only one of the m md mm or mmd options can be present if multiple of these options are listed the last one listed is accepted and the others are ignored m print makefile dependencies to stdout md print makefile dependencies to filename d where filename is the root name of the input file being processed mm print makefile dependencies to stdout ignoring system include files mmd print makefile dependencies to filename d where filename is the root name of the input file being processed ignoring system include files Command Line Options Md11 Mgccbug s Minfol option option no comment don t retain comments in ed output suffix lt suff gt use lt suff gt as the suffix of the output file containing makefile dependencies Windows only link with the DLL versions of the runtime libraries This flag is required when linking with any DLL built by any of The Portland Group compilers match the behavior of certain gcc bugs I instructs the compiler to produce information on standard error where option is one of the following all instructs the compiler to produce all available Minfo inf
233. ript expression must be integer If it is not it is converted Messages 185 104 Illegal control structure This message is issued for a number of errors involving IF THEN statements and DO loops If the line number specified is the last line END statement of the subprogram the error is probably an unterminated DO loop or IF THEN statement S105 Unmatched ELSEIF ELSE or ENDIF statement An ELSEIF ELSE or ENDIF statement cannot be matched with a preceding IF THEN statement 106 DO index variable must be a scalar variable The DO index variable cannot be an array name a subscripted variable a PARAMETER name a function name a structure name etc 107 Illegal assigned goto variable 108 Illegal variable in NAMELIST group A NAMELIST group can only consist of arrays and scalars which are not dummy arguments and pointer based variables I109 Overflow in constant constant truncated at left A non decimal hexadecimal octal or binary constant requiring more than 64 bits produces an overflow The constant is truncated at left e g 1234567890abcdef1 x will be 234567890abcdef1 x I110 lt reserved message number gt I111 Underflow of real or double precision constant I112 Overflow of real or double precision constant S113 Label is referenced but never defined S114 Cannot initialize 186 Messages W115 Assignment to DO variable in loop 116 Illegal use of pointer based variable S
234. rivate variables or local variables in functions or subroutines called within parallel regions The value should be an integer lt n gt concatenated with M or m to specify stack sizes of n megabytes For example setenv MPSTKZ 8M To set the environment for programs run from within PVF whether they are run in the debugger are not use the environment properties in the Debugging property page 120 OpenMP Directives for Fortran Chapter 7 Optimization Directives Directives are Fortran comments that the user may supply in a Fortran source file to provide information to the compiler Directives alter the effects of certain command line options or default behavior of the compiler While a command line option affects the entire source file that is being compiled directives apply or disable the effects of a command line option to selected subprograms or to selected loops in the source file for example an optimization Use directives to tune selected routines or loops 7 1 Adding Directives to Fortran Directives may have any of the following forms cpgi g directive cpgi r directive cpgi l directive cpgi directive The C must be in column 1 Either or is allowed in place of C The scope indicator occurs after the this indicator controls the scope of the directive Some directives ignore the scope indicator The valid scopes as shown above are g global indicates the directive applies to the end of the source file T routi
235. rogram name in a CALL statement or is called as a function and is therefore assumed to be a dummy procedure This message can result from a failure to declare a dummy array I126 Name is not an intrinsic function I127 Optimization level for changed to opt 1 W128 Integer constant truncated to fit data type An integer constant will be truncated when assigned to data types smaller than 32 bits such as a BYTE I129 Floating point overflow Check constants and constant expressions I130 Floating point underflow Check constants and constant expressions I131 Integer overflow Check floating point expressions cast to integer I132 Floating pt invalid oprnd Check constants and constant expressions I133 Divide by 0 0 Check constants and constant expressions 134 Illegal attribute W135 Missing STRUCTURE name field A STRUCTURE name field is required on the outermost structure 188 Messages W136 Field namelist not allowed The field namelist field of the STRUCTURE statement is disallowed on the outermost structure W137 Field namelist is required in nested structures W138 Multiply defined STRUCTURE member name A member name was used more than once within a structure W139 Structure in RECORD statement not defined A RECORD statement contains a reference to a STRUCTURE that has not yet been defined S140 Variable is not a RECORD 141 RECORD required on left of 142 is not a member of this RECO
236. rough A3 4 4 define the Fortran supplement to the AMD64 Software Conventions for Win64 The register usage conventions set forth in that document remain the same for Fortran Run time Environment 165 A 2 4 1 Fortran Fundamental Types Table A 10 Win64 Fortran Fundamental Types Fortran Type aes Ee Sa INTEGER 4 4 INTEGER 1 1 1 INTEGER 2 2 2 INTEGER 4 4 4 INTEGER 8 8 8 LOGICAL 4 4 LOGICAL 1 1 1 LOGICAL 2 2 2 LOGICAL 4 4 4 LOGICAL 8 8 8 BYTE 1 1 CHARACTER n n 1 REAL 4 4 REAL 4 4 4 REAL 8 8 8 DOUBLE PRECISION 8 8 COMPLEX 8 4 COMPLEX 8 8 4 COMPLEX 16 16 8 DOUBLE COMPLEX 16 8 A logical constant is one of TRUE FALSE 166 Run time Environment The logical constants TRUE and FALSE are defined to be the four byte values 1 and 0 respectively A logical expression is defined to be TRUE if its least significant bit is 1 and FALSE otherwise Note that the value of a character is not automatically NULL terminated A 2 4 2 Fortran Naming Conventions By default all globally visible Fortran symbol names subroutines functions common blocks are converted to lower case In addition an underscore is appended to Fortran global names to distinguish the Fortran name space from the C C name space A 2 4 3 Fortran Argument Passing and Return Conventions Arguments are passed by reference i e the address of the argument is pas
237. rray specification ignored S435 Array declared with zero size An array was declared with a zero or negative dimension bound as real a 1 or an upper bound less than the lower bound as real a 4 2 W436 Independent loop not parallelized W437 Type will be mapped to Where DOUBLE PRECISION is not supported it is mapped to REAL and similarly for COMPLEX 16 or COMPLEX 372 E438 not supported on this platform This construct is not supported by the compiler for this target S439 An internal subprogram cannot be passed as argument S440 Defined assignment statements may not appear in WHERE statement or WHERE block S441 may not appear in a FORALL block Messages 213 E442 Adjustable length character type not supported on this host S443 EQUIVALENCE of derived types not supported on this host S444 Derived type in EQUIVALENCE statement must have SEQUENCE attribute A variable or array with derived type appears in an EQUIVALENCE statement The derived type must have the SEQUENCE attribute but does not E445 Array bounds must be integer The expressions in the array bounds must be integer 446 Argument number to rank mismatch The number of dimensions in the array or array expression does not match the number of dimensions in the dummy argument 447 Argument number to must be a subroutine or function name 448 Argument number to must be a subroutine name S449 Argumen
238. rted to a data type that was not large enough to contain all of the characters in the constant This type conversion occurs when the constant is used in an arithmetic expression or is assigned to a non character variable The character or hollerith constant is truncated on the right that is if 4 characters are needed then the first 4 are used and the remaining characters are discarded w025 Illegal character ignored The current line contains a character possibly non printing which is not a legal Fortran character characters inside of character or Hollerith constants cannot cause this error As a general rule all non printing characters are treated as white space characters blanks and tabs no error message is generated when this occurs If for some reason a non printing character is not treated as a white space character its hex representation is printed in the form dd where each d is a hex digit S026 Unmatched quote 027 Illegal integer constant Integer constant is too large for 32 bit word 028 Illegal real or double precision constant 029 Illegal constant Illegal hexadecimal octal or binary constant A hexadecimal constant consists of digits 0 9 and letters A F or a f any other character in a hexadecimal constant is illegal An octal constant consists of digits 0 7 any other digit or character in an octal constant is illegal A binary constant consists of digits 0 or 7 any other digit or character i
239. ructs the compiler to display error messages at the specified and higher levels where level is one of the following inform fatal instructs the compiler to display fatal error messages severe instructs the compiler to display severe and fatal error messages warn instructs the compiler to display warning severe and fatal error messages inform informinstructs the compiler to display all error messages inform warn severe and fatal To set this option in PVF use the Fortran General Warning Level property instructs the compiler to keep the assembly file as compilation continues Normally the assembler deletes this file when it is finished The assembly file has the same filename as the source file but with a s extension To set this option in PVF use the Fortran Output Assembler Output property instructs the compiler to create a listing file The listing file is filename I st where the name of the source file is filename f the compiler does not create a listing file This is the default generate a dynamic link library DLL when used in combination with the mp option causes the compiler to ignore OpenMP parallelization directives or pragmas but still process SGI style parallelization directives or pragmas when used in combination with the mp option causes the compiler to ignore SGI style parallelization directives or pragmas but still process OpenMP parallelization directives or pragmas Command Line Option
240. s For the above program w has a value of 1 8446744E 19 when executed using default extended precision If however Kieee is set the value becomes 1 6777216E 07 single precision This difference is due to the fact that Kieee disables copy propagation so all intermediate results are stored into memory then reloaded when needed Copy propagation is only disabled for floating point operations not integer With this particular example setting the pc switch will also adjust the result The switch Kieee also has the effect of making function calls to perform all transcendental operations Although the function still produces the x86 machine instruction for computation unless in C the Mnobuiltin switch is set arguments are passed on the stack which results in a memory store and load Finally Kieee also disables reciprocal division for constant divisors That is for a b with unknown a and constant b the expression is usually converted at compile time to a 1 b thus turning an expensive divide into a relatively fast scalar multiplication However numerical discrepancies can occur when this optimization is used Understanding and correctly using the pc Mnobuiltin and Kieee switches should enable you to produce the desired and expected precision for calculations which utilize floating point operations Usage pgf95 pc 64 myprog c Selects variations for compilation There are four uses for the Q option Syntax Qdirdi
241. s Mnopgdllimain Do not link the module containing the default DU Man into the DLL If you want to replace the default DlIMain routine with a custom DIIMain Q use this flag and add the object containing the custom DllMain to the link line The latest version of the default DI Main used by PGF95 is included in the Release Notes for each release the PGF95 specific code in this routine must be incorporated into the custom version of DllMain to ensure the appropriate function of your DLL Mpreprocess perform cpp like pre processing on assembly and Fortran input source files To set this option in PVF use the Fortran Preprocessor Preprocess Source File property Default For arguments that you do not specify the default miscellaneous options are as follows inform warn nolist nobounds Usage In the following example the compiler includes Fortran source code with the assembly code pgf95 Manno S myprog f In the following example the compiler displays information about inlined functions with fewer than approximately 20 source lines in the source file myprog f pgf95 Minfo inline Minline 20 myprog f In the following example the assembler does not delete the assembly file myprog s after the assembly pass pgf95 Mkeepasm myprog f In the following example the compiler creates the listing file myprog Ist pgf95 Mlist myprog f In the following example array bounds checking is enabled pgf95 Mbounds m
242. s The command used to invoke a compiler for example the pgf95 command is called a compiler driver The compiler driver controls the following phases of compilation preprocessing compiling assembling and linking Once a file is compiled and an executable file is produced you can execute debug or profile the program on your system Executables produced by the PGI compilers are unconstrained meaning they can be executed on any compatible x86 or x64 processor based system regardless of whether the PGI compilers are installed on that system 2 1 Overview In general using a PGI compiler involves three steps 1 Produce a program in a file containing a f extension or another appropriate extension see Section 2 3 1 Input Files This may be a program that you have written or a program that you are modifying 2 Compile the program using the appropriate compiler command 3 Execute debug or profile the executable file on your system The PGI compilers allow many variations on these general program development steps These variations include the following Stop the compilation after preprocessing compiling or assembling to save and examine intermediate results e Provide options to the driver that control compiler optimization or that specify various features or limitations e Include as input intermediate files such as preprocessor output compiler output or assembler output 2 2 Invoking the Command level PGI Compilers
243. s executed whenever the loop count is less than or equal to n If noaltcode is specified no alternate serial code is generated 36 Optimization amp Parallelization 3 6 1 2 Dist Option The option Mconcur dist blocklcyclic option specifies whether to assign loop iterations to the available threads in blocks or in a cyclic round robin fashion Block distribution is the default If cyclic is specified iterations are allocated to processors cyclically That is processor 0 performs iterations 0 3 6 etc processor performs iterations 1 4 7 etc and processor 2 performs iterations 2 5 8 etc 3 6 1 3 Cncall Option The option Mconcur cncall specifies that it is safe to parallelize loops that contain subroutine or function calls By default such loops are excluded from consideration for auto parallelization Also no minimum loop count threshold must be satisfied before parallelization will occur and last values of scalars are assumed to be safe The environment variable NCPUS is checked at runtime for a parallel program If NCPUS is set to 1 a parallel program runs serially but will use the parallel routines generated during compilation If NCPUS is set to a value greater than 1 the specified number of processors will be used to execute the program Setting NCPUS to a value exceeding the number of physical processors can produce inefficient execution Executing a program on multiple processors in an environment where some
244. s itself recursively The following command line creates the file fibo o in which fibo is inlined into itself pgf95 fibo f c Mrecursive Minline fibo Because this version of fibo recurses only half as deeply it executes noticeably faster Using the same source file dhry f the following example builds an executable for dhry in which all functions of roughly ten or fewer statements are inlined Two levels of inlining are performed This means that if function A calls function B and B calls C and both B and C are inlinable then the version of B which is inlined into A will have had C inlined into it pgf95 dhry f Minline size 10 levels 2 5 5 Restrictions on Inlining The following Fortran subprograms cannot be extracted e Main or BLOCK DATA programs e Subprograms containing alternate return assigned GO TO DATA SAVE or EQUIVALENCE statements e Subprograms containing FORMAT statements Subprograms containing multiple entries A Fortran subprogram is not inlined if any of the following applies e It is referenced in a statement function e A common block mismatch exists i e the caller must contain all common blocks specified in the callee and elements of the common blocks must agree in name order and type except that the caller s common block can have additional members appended to the end of the common block e An argument mismatch exists i e the number and type size of actual and formal parameters must be e
245. s saves its information in special IPA files in the specified IPA directory One of these files has been renamed or corrupted This can arise when there are two files with the same prefix such as a hpf and a f90 E416 Argument has the SEQUENCE attribute but the dummy parameter does not When an actual argument is an array with the SEQUENCE attribute the dummy parameter must have the SEQUENCE attribute or an INTERFACE block must be used E417 Interface block for is a SUBROUTINE but should be a FUNCTION Messages 211 E418 E419 W420 W421 E422 E423 E424 E425 E426 E427 E428 E429 212 Interface block for is a FUNCTION but should be a SUBROUTINE Interface block for is a FUNCTION has wrong result type Earlier directive overrides directive directive can only appear in a function or subroutine Nonconstant DIM argument is not supported Constant DIM argument is out of range Equivalence using substring or vector triplets is not allowed A record is not allowed in this context WORD type cannot be converted Interface block for has wrong number of arguments Interface block for should have Interface block for should not have Messages E430 Interface block for has wrong W431 Program is too large for Interprocedural Analysis to complete W432 Illegal type conversion E433 Subprogram called within INDEPENDENT loop not LOCAL W434 Incorrect home a
246. s to be returned in memory the caller provides space for the return value and passes its address to the function as a hidden first argument in rcx This address will also be returned in rax A 2 3 Argument Passing Integral and Pointer Arguments Integral and pointer arguments are passed to a function using the next available register of the sequence rcx Yordx r8 r9 After this list of registers has been exhausted all remaining integral and pointer arguments are passed to the function via the stack Floating Point Arguments Float and double arguments are passed to a function using the next available XMM register of the sequence xmm0 xmm1 xmm2 xmm3 After this list of registers has been exhausted all remaining XMM floating point arguments are passed to the function via the stack Array Structure and Union Arguments Arrays and strings are passed to functions using a pointer to caller allocated memory Structure and union arguments of size 1 2 4 or 8 bytes will be passed as if they were integers of the same size Structures and unions of other sizes will be passed as a pointer to a temporary allocated by the caller and whose value contains the value of the argument The caller allocated temporary memory used for arguments of aggregate type must be 16 byte aligned Passing Arguments on the Stack Registers are assigned using the argument s ordinal position in the argument list For example if a function s firs
247. sed rather than the argument itself In contrast C C arguments are passed by value When passing an argument declared as Fortran type CHARACTER an argument representing the length of the CHARACTER argument is also passed to the function This length argument is a four byte integer passed by value and is passed at the end of the parameter list following the other formal arguments A length argument is passed for each CHARACTER argument the length arguments are passed in the same order as their respective CHARACTER arguments A Fortran function returning a value of type CHARACTER adds two arguments to the beginning of its argument list The first additional argument is the address of the area created by the caller for the return value the second additional argument is the length of the return value If a Fortran function is declared to return a character value of constant length for example CHARACTER 4 FUNCTION CHF the second extra parameter representing the length of the return value must still be supplied A Fortran complex function returns its value in memory The caller provides space for the return value and passes the address of this storage as if it were the first argument to the function Alternate return specifiers of a Fortran function are not passed as arguments by the caller The alternate return function passes the appropriate return value back to the caller in rax The handling of the following Fortran 90 features is impl
248. seeeeeeeseneeeeenseeeeeeeeeseeeeeess 1 Creating a PVF Project ccccccececceesncececeeeeeeeeeeceaeeeeeaeeeseaeeeseeneesseaeeeeeaeeeeaas 1 Migrating an Existing Application to PVF uu eeeseeeeeeeeneeeeeeeeenaaeeeeeeenaas 2 PVE Solution Explorer icscsiscd ceesaenss iegiseahessedaen aE candida cisanosasta eetanendengendenags 2 PVE IEditorFeatures edel E Mou heess cht See eech A 3 Setting Global User Options 3 Setting Configuration Options in PVF o ceeeccececeeeeeeeeeeeceeeeeeeeeeseeeeeeeeeees 4 Setting File Properties in PVF ccccccecseeeeseeeeceeeeeeeeeeseeeeseaaeeseeaeeeseaeeeeeas 4 Building a Project With PVF A 5 Order of PVF Build Operations 0 cccccceeeeeeeeeeeeeeeeneeeeeceeeeeeeeeesetaeeeeneeees 5 Custom Build Step and Build Events 0 c ccceceeeeeeeeeeeceeeeseeeeeeeeeeeeeeeees 6 PVE Build MACOS EE 6 Debugging WiN GA SE 8 OMIM WI NEE Aessen eebe EC 9 VC Interoperability sirs deurran eira ae a aa a aia 9 Using PVF Online Help ssssssssseesseeesseesssnsssessssrnssrnsssrnrsrnnennnnnnnnnennnssrnesrnns 10 The PVF Command Environment cccccccceceeeeeeececeeeeeeeeeeeeeeeeneeeesaees 10 PVF Sample Projects e rr a i Aaaa a aaaea a tiaa adapa aE AEA aaa EDERE ES 10 GOEN aeaieo n Mat cheated genge ele deet Reser daa ean 10 WiN 2 leen EE 11 Fortran Module Library Interfaces AAA 11 Portability Interfaces UNIX LINUX oe eee eee eeeeeee eee eeeeaeeeeeeeeaeeeeeeeeaaees 12 Data TY DOS siet ere d ses e
249. specified as Pre Build Pre Link and Post Build See Section 1 8 1 Order of PVF Build Operations for specifics of where build events are run in the PVF build Build events are always run unless the project is up to date There is no dependency checking for build events Define build events using the property pages for the project Custom Build Steps may apply to either individual files or the project If applied to an individual file dependencies may be specified Dependencies must be out of date for a Custom Build Step to run When defined for a project the Custom Build Step does not check dependencies in this case the Custom Build Step is very similar to the Post Build Event Define Custom Build Steps using the property pages for the file or project 1 10 PVF Build Macros PVF implements a subset of the build macros supported by Visual C along with a few PGI specific macros The macro names are not case sensitive and they should be usable in any string field in a property page Unless otherwise noted macros that evaluate to directory names end with a trailing backslash In general these Items can only be changed if there is an associated PVF project or file property For example VCInstallDir cannot be changed while IntDir can be changed by modifying the General Intermediate Directory property The table below lists the supported macros 6 Getting Started with PVF Table 1 1 PVF Build Macros Macro Name Des
250. ssed For each auto parallelized loop generate an alternate serial loop to be executed if the loop count is less than or equal to n If n is omitted or n is O the compiler determines a suitable value of n for each loop This directive sets the loop count threshold for parallelization of reduction loops to n For each auto parallelized reduction loop generate an alternate serial loop to be executed if the loop count is less than or equal to n If n is omitted or n is 0 the compiler determines a suitable value of n for each loop For a vectorized loop if possible generate an alternate vectorized loop containing non temporal stores and other cache optimizations to be executed if the loop count is greater than n If n is omitted or n is 1 the compiler determines a suitable value of n for each loop The alternate code is optimized for the case when the data referenced in the loop does not all fit in level 2 cache For a vectorized loop where iteration peeling is performed by default if possible generate an alternate vectorized loop without iteration peeling to be executed if the loop count is less than or equal to n If nis omitted or n is 1 the compiler determines a suitable value of n for each loop and in some cases it may decide not to generate an alternate unpeeled loop For each vectorized loop generate an alternate scalar loop to be executed if the loop count is less than or equal to n If n is omitted or nis 1 the compiler determi
251. t argument is an integral type and its second argument is a floating point type the first argument will be passed in the first general purpose register Yorcx and the second argument will be passed in the second XMM register xmm1 the first XMM register and second general purpose register are ignored Arguments after the first four are passed on the stack they are pushed on the stack in reverse order with the last argument pushed first 162 Run time Environment Table A 9 Register Allocation for Example A 4 shows the register allocation and stack frame offsets for the function declaration and call shown in the following example Example A 2 Parameter Passing typedef struct int i float f structl int i float f double d long 1 long long 11 SETUCEL s1 extern void func int i float f structl1 sl double d long long 11 long 1 func i f sit d 11 1 Table A 9 Register Allocation for Example A 4 General Purpose d f Stack Frame Registers Floating Point Registers Offset rcx i xmm0 lt ignored gt 32 11 rdx lt ignored gt xmml f 40 1 r8 s1 i s1 f xmm2 lt ignored gt r9 lt ignored gt xmm3 d Implementing a Stack In general compilers and programmers must maintain a software stack The stack pointer register Yorsp is set by the operating system for the application when the program is started The stack must grow downwards from high addresses
252. t be a structured block It is illegal to branch into or out of the block A given iteration of a loop with a DO directive cannot execute the same ORDERED directive more than once and cannot execute more than one ORDERED directive 6 15 ATOMIC The OpenMP ATOMIC directive uses following syntax SOMP ATOMIC The ATOMIC directive is semantically equivalent to enclosing the following single statement in a CRITICAL END CRITICAL directive pair The statement must be of one of the following forms x X operator expr 116 OpenMP Directives for Fortran x expr operator x X intrinsic x expr X intrinsic expr x where x is a scalar variable of intrinsic type expr is a scalar expression that does not reference x intrinsic is one of MAX MIN LAND IOR or IEOR and operator is one of AND OR EQV or NEQV 6 16 FLUSH The OpenMP FLUSH directive uses the following syntax SOMP FLUSH list The FLUSH directive ensures that all processor visible data items or only those specified in list when it s present are written back to memory at the point at which the directive appears 6 17 THREADPRIVATE The OpenMP THREADPRIVATE directive uses the following syntax SOMP THREADPRIVATE list Where list is a comma separated list of named variables to be made private to each thread or named common blocks to be made private to each thread but global within the thread Common block names must appear between sl
253. t not backward compatible That means code compiled to target a given processor will not necessarily execute correctly on a previous generation processor The most important processor types along with a list of the features utilized by the PGI compilers that distinguish them from a compatibility standpoint are listed in the following table xii Preface Table P 2 Processor Options Processor Prefetch SSE SSE SSE 32 64 Scalar FP 1 2 3 bit bit Default AMD Athlon X x87 AMD Athlon XP MP X X X x87 AMD Athlon64 X X X X X SSE AMD Opteron X X X X X SSE AMD Opteron Rev E X X X X X SSE AMD Turion X X X X X SSE Intel Celeron X x87 Intel Pentium H X x87 Intel Pentium III x x x x87 Intel Pentium 4 x x X X SSE Intel Pentium M X X X X SSE Intel Centrino X X X X SSE Intel Pentium 4 EM64T X X X X SSE Intel Xeon EM64T X X X X SSE Intel Core 2 EM64T X X X X SSE In this manual the convention is to use x86 to specify the group of processors in the previous table that are listed as 32 bit but not 64 bit The convention is to use x64 to specify the group of processors that are listed as both 32 bit and 64 bit x86 processor based systems can run only 32 bit operating systems x64 processor based systems can run either 32 bit or 64 bit operating systems and can execute all 32 bit x86 binaries in either case x64 processors have additional registers
254. t number to must be a function name 450 Argument number to kind mismatch 451 Arrays of derived type with a distributed member are not supported 452 Assumed length character is not a dummy argument 214 Messages S453 Derived type variable with pointer member not allowed in IO S454 Subprogram is not a module procedure Only names of module procedures declared in this module or accessed through USE association can appear ina MODULE PROCEDURE statement S455 A derived type array section cannot appear with a member array section A reference like A B where A is a derived type array and B is a member array is not allowed a section subscript may appear after A or after B but not both S456 Unimplemented for data type for MATMUL S457 Illegal expression in initialization S458 Argument to NULL must be a pointer S459 Target of NULL assignment must be a pointer S460 ELEMENTAL procedures cannot be RECURSIVE S461 Dummy arguements of ELEMENATAL procedures must be scalar S462 Arguments and return values of ELEMENATAL procedures cannot have the POINTER attribute S463 Arguments of ELEMENATAL procedures cannot be procedures S464 An ELEMENTAL procedure cannot be passed as argument Messages 215 BA Fortran Runtime Error Messages This section presents the error messages generated by the runtime system The runtime system displays error messages on standard output B 4
255. ter usage and parameter passing A 1 1 1 Register Usage Conventions The following table defines the standard for register allocation The 32 bit x86 Architecture provides a number of registers All the integer registers and all the floating point registers are global to all procedures in a running program 149 Table A 1 Register Allocation Type Name Purpose General Joeax integer return value Joedx dividend register for divide operations pecx count register shift and string operations Joebx local register variable ebp optional stack frame pointer oesi local register variable Jedi local register variable hesp stack pointer Floating point st 0 floating point stack top return value st 1 floating point next to stack top st st 7 floating point stack bottom In addition to the registers each function has a frame on the run time stack This stack grows downward from high addresses The next table shows the stack frame organization 150 Run time Environment Table A 2 Standard Stack Frame Position Contents Frame 4n 8 ebp argument word n previous 8 ebp argument word 0 4 ebp return address 0 ebp caller s ebp current 4 ebp n bytes of local n ebp variables and temps Several key points concerning the stack frame e The stack is kept double word aligned e Argument words are pushed onto the stack in re
256. ters in a macro call to the indicated macro exceeded the maximum allowed currently 2048 W225 Argument mismatch for The number of arguments supplied in the call to the indicated macro did not agree with the number of parameters in the macro s definition F226 Can t find include file The indicated include file could not be opened 227 Definition too long for The length of the macro definition of the indicated macro exceeded the maximum allowed currently 2048 S228 EOF in comment The end of a file was encountered while processing a comment S229 EOF in macro call to 196 Messages The end of a file was encountered while processing a call to the indicated macro 230 EOF in string The end of a file was encountered while processing a quoted string 231 Formal parameters too long for The total length of the parameters in the definition of the indicated macro exceeded the maximum allowed currently 2048 232 Identifier too long The length of an identifier exceeded the maximum allowed currently 2048 S233 lt reserved message number gt W234 Illegal directive name The sequence of characters following a sign was not an identifier W235 Illegal macro name A macro name was not an identifier 236 Illegal number The indicated number contained a syntax error F237 Line too long The input source line length exceeded the maximum allowed currently 2048 W238 Missing endif End o
257. that the compiler provide special compilation semantics Syntax K lt flag gt Where flag is one of the following ieee Perform floating point operations in strict conformance with the IEEE 754 standard Some optimizations are disabled and on some systems a more accurate math library is linked if Kieee is used during the link step To set this option in PVF use the Fortran Floating Point Options IEEE Arithmetic property noieee Use the fastest available means to perform floating point operations link in faster non IEEE libraries if available and disable underflow traps trap option option Controls the behavior of the processor when floating point exceptions occur Possible options include b fp e align ignored e inv e denorm e divz e ovf e unf e inexact Ktrap is only processed by the compilers when compiling main functions programs The options inv denorm divz ovf unf and inexact correspond to the processor s exception mask bits invalid operation denormalized operand divide by zero overflow underflow and precision respectively Normally the processor s exception mask bits are on floating point exceptions are 58 Command Line Options masked the processor recovers from the exceptions and continues If a floating point exception occurs and its corresponding mask bit is off or unmasked execution terminates with an arithmetic exception C s SIGFPE signal Ktrap fp is equivalent to
258. the IPA linker is invoked it will determine that the IPA optimized object for file 1 obj file 1_ipa5_a out obj is stale since it is older than the object Dlel obt and hence will need to be rebuilt and will reinvoke the compiler to generate it In addition depending on the nature of the changes to the source file file1 f95 the interprocedural optimizations previously performed for file2 and file3 may now be inaccurate For instance IPA may have propagated a constant argument value in a call from a function in file1 f95 to a function in file2 f95 if the value of the argument has changed any optimizations based on that constant value are invalid The IPA linker will determine which if any of any previously created IPA optimized objects need to be regenerated and will reinvoke the compiler as appropriate to regenerate them Only those objects that are stale or which have new or different IPA information will be regenerated which saves on compile time 3 7 7 Building a Program with IPA Using Make As in the previous two sections programs can be built with IPA using the make utility just by adding the Mipa command line switch pgf95 S OPT o filel exe filel obj file2 obj file3 obj filel obj filel f 95 pgf95 S OPT c filel f95 file2 obj file2 95 pgf95 S OPT c file2 95 file3 obj file3 95 pgf95 S OPT c file3 95 The single command o nmake will invoke the compiler to generate any object files th
259. the PGI compilers The c must be in column 1 Either or is allowed in place of c The scope indicators g r and 1 used with the cpgi sentinel are not supported The directive name including the directive prefix may contain upper or lower case letters case is not significant Case is significant for any variable names that appear in the body of the directive if the command line option Mupcase is selected An example using prefetch directives to prefetch data in a matrix multiplication inner loop where a row of one source matrix has been gathered into a contiguous vector might look as follows Optimization Directives 131 real 8 a m n b n p c m p arow n do j 1 p c mem prefetch arow 1 b 1 j cSmem prefetch arow 5 b 5 j cSmem prefetch arow 9 b 9 j do k 1 n 4 c mem prefetch arow k 12 b k 12 j e i j c i j arow k b k j e i j c i j arow k 1 b k 1 j e i j c i j arow k 2 b k 2 j e i j c i j arow k 3 b k 3 j enddo enddo This pattern of prefetch directives will cause the compiler to emit prefetch instructions whereby elements of arow and b are fetched into the data cache starting 4 iterations prior to first use By varying the prefetch distance in this way it is possible in some cases to reduce the effects of main memory latency and improve performance 132 Optimization Directives Chapter 8 Libraries and Environment Variables This chapter discusses issues related
260. the open statement is in units of 4 byte words and the edit descriptor only has an effect for lines beginning with a space or If this variable exists and contains the value format_relaxed an I O item corresponding to a numerical edit descriptor F E I etc is not required to be a type implied by the descriptor For example setenv FORTRAN_OPT vaxio will cause the PGI Fortran compilers to use VAX I O conventions as defined above MPSTKZ increase the size of the stacks used by threads executing in parallel regions It is for use with programs that utilize large amounts of thread local storage in the form of private variables or local variables in functions or subroutines called within parallel regions The value should be an integer lt n gt concatenated with M or m to specify stack sizes of n megabytes For example setenv MPSTKZ 8M MP_BIND the MP_BIND environment variable can be set to yes or y to bind processes or threads executing in a parallel region to physical processors or to no or n to disable such binding The default is to not bind processes to processors This is an execution time environment variable interpreted by the PGI runtime support libraries It does not affect the behavior of the PGI compilers in any way Note the MP_BIND environment variable is not supported on all platforms MP_BLIST In addition to the MP_BIND variable it is possible to define the thread CPU relationship For example setting MP_BLIST 3
261. their corresponding source files and invokes the compiler to recompile only those source files and to relink the executable If you subsequently edit one or more source files the executable can be rebuilt with the minimum number of recompilations using the same single make command 3 7 4 Building a Program with IPA Interprocedural analysis and optimization IPA by the PGI compilers is designed to alter the standard and make utility command level interfaces outlined above as little as possible IPA occurs in three phases Collection Create a summary of each function or procedure collecting the useful information for interprocedural optimizations This is done during the compile step if the Mipa switch is present on the command line summary information is collected and stored in the object file e Propagation Processing all the object files to propagate the interprocedural summary information across function and file boundaries This is done during the link step when all the object files are combined if the Mipa switch is present on the link command line Recompile Optimization Each of the object files is recompiled with the propagated interprocedural information producing a specialized object file This is also done during the link step when the Mipa switch is present on the link command line When linking with Mipa the PGI compilers automatically regenerate IPA optimized versions of each object file essentially recompili
262. then advance the seed by a variable amount based on time Subsequent calls to RANDOM_SEED without arguments will reset the random seed to the same initial value as the first call Unless the time is exactly the same each time a program is run a different random number sequence will be generated You can force the seed returned by RANDOM_SEED to be constant thereby generating the same sequence of random numbers at each execution of the program by setting the environment variable STATIC_RANDOM_SEED to yes PGI_TERM The stack traceback and just in time debugging functionality is controlled by the PGI_TERM environment variable The run time libraries use the value of PGI_TERM to determine what action to take when a progam abnormally terminates Libraries and Environment Variables 139 PGI_TERM_DEBUG The PGILTERM_DEBUG variable may be set to override the default behavior when PGI_TERM is set to debug TMPDIR Can be used to specify the directory that should be used for placement of any temporary files created during execution of the PGI compilers and tools 140 Libraries and Environment Variables Chapter 9 Fortran Data Types This chapter describes the scalar and aggregate data types recognized by the PGI Fortran compilers the format and alignment of each type in memory and the range of values each type can take on x86 or x64 processor based systems running a 32 bit operating system This chapter specifically does not address x64 processor
263. there are less than four register parameters used in a given call Sixteen byte alignment of the stack is required except within a function s prolog and within leaf functions All registers on an x64 system are global and thus visible to both a calling and a called function Registers rbx rsp rbp rsi rdi r12 r13 r14 and r15 are non volatile Therefore a called function must preserve these registers values for its caller Remaining registers are scratch If a calling function wants to preserve such a register value across a function call it must save a value in its local stack frame Registers are used in the standard calling sequence The first four arguments are passed in registers Integral and pointer arguments are passed in these general purpose registers listed in order rcx rdx r8 r9 Floating point arguments are passed in the first four XMM registers xmm0 Gamm xmm2 xmm3 Registers are assigned using the argument s ordinal position in the argument list For example if a function s first argument is an integral type and its second argument is a floating point type the first argument will be passed in the first general purpose register rcx and the second argument will be passed in the second XMM register xmm1 the first XMM register and second general purpose register are ignored Arguments after the first four are passed on the stack 160 Run time Environment Integral and pointer type retur
264. timization A ParalleliZation cc ceecceseseeeeeeseeeeeeeeeeeeeeeneeeeees 23 Overview Of Optimization eccceccsceececeeeeeeeeeeeaeeeeeeeeeseaeeeeeaeeeeecaeeeeeeeees 23 Getting Started with Optimizations ccceecceeceeeeeeeeeeeeeeeeeeeeeeesetaeeeeeeeeees 25 Local and Global Optimization USING 03 26 Scalar SSE Code Generation cccccceeceeeeeeeeeeeeeeeeeeeeeaeeeeeeeeesaeeneeeeees 28 Loop Unrolling using Munroll 2 ee eeeceeeeeenneeeeeeeeeeeeeeeeeaeeeeeeeeaeeeeeeenas 29 Vectorization USING Mvect AA 30 Vectorization SUD OptionS ceccececeeeceeeeeeeeeeeceaeeeeeeeeesaeeeseeeeeseaeeeeenees 31 Assoc Ee Le EE 32 GaChESiZe QPO raseria isrado dakoie aere eege deed diay 32 SSE El EE 32 Pr fetch Option sue inc tive di a ana a ten tan ea cede eles 32 Vectorization Example Using SSE SSE2 Instructions 33 Auto Parallelization using Meonceur 0 0 2 eeeeeeeeeeeeeeeeeeeeeeeeeeeeteeeeeeeeeeeeeaees 36 Auto parallelization SUD OptionS 36 AltCOde Option TEE 36 DistOption eege ted ees ee eee ae 37 Gncall le le 37 Loops That Fail to ParalleliZe AA 37 IPNSrMOSt LOOPS EE 38 Timing LOOPS EE 38 SCAU AE ass geen etau nah abdesseucesun Eege 38 scalar Last Values fives Bi daa ASATZ Ae 39 Inter Procedural Analysis and Optimization using Mipa eseeeeeee 40 Building a Program Without IPA Single Step cceeeeeseeeeeeeeeeeeeeee 41 Building a Program Without IPA Several Steps cc
265. tran Runtime Error Messages assssssssriesssssrresrrrnrnnsrnnnneeernnnnesrnnnnenas 216 Massage Gen EE 216 Message BCEE 216 Contents Tables Table P 1 Table P 2 Table 1 1 Table 1 2 Table 1 3 Table 2 1 Table 3 1 Table 4 1 Table 4 2 Table 4 3 Table 6 1 Table 7 1 Table 9 1 Table 9 2 Table 9 3 Table A 1 Table A 2 Table A 3 Table A 4 Table A 5 Table A 6 Table A 7 Table A 8 Table A 9 Table A 10 Table A 11 Table A 12 PGI Compilers and Commande rnnr rst nensrnnssrnnssrnssent xii Processor OPTIONS EE xiii PVF Build Maergg foia an ate ara E aon Aina eel 7 PVF Win32 API Module Mappings sssssssssesssssrrrsssrrrssrrrnsssrirrsssrirnrssrrnnnsns 11 Fortran Data Type Mappings esureosssierrene eanas EANA AEA RNE 13 Stop after Options Inputs and Output 19 Optimization and O g and M lt opt gt Options ceceeeeeeeeeeeeeeeteeeees 47 Generic PGI Compiler Options cccceeeeeeceeeeeeeeeeeeeeeeaeeeeaaeesenaeeesnaeessaes 50 M Options Summary Asosini led canens ERKENNEN ened a ea ainai 61 Optimization and O g Mvect and Mconcur Options eceees 87 Initialization of REDUCTION Variables ccccecceeeceeeeeeeeseeeeeeeeeeeneeeeees 106 Fortran Optimization Directive Gummanm 123 Representation of Fortran Data Types cccceceeseeeeeeeeeneeeeeeeennaeeeeeeeeaees 142 Real Data Type Ranges crame a aaa e RE E E EA 144 Scalar Type AliQnment
266. ues can arise which affect your numerical results sometimes to several digits of accuracy 3 4 Loop Unrolling using Munroll This optimization unrolls loops executing multiple instances of the loop during each iteration This reduces branch overhead and can improve execution speed by creating better opportunities for instruction scheduling A loop with a constant count may be completely unrolled or partially unrolled A loop with a non constant count may also be unrolled A candidate loop must be an innermost loop containing one to four blocks of code The following shows the use of the Munroll option pgf95 Munroll prog f The Munroll option is included as part of fast and fastsse on all x86 and x64 targets The loop unroller expands the contents of a loop and reduces the number of times a loop is executed Branching overhead is reduced when a loop is unrolled two or more times since each iteration of the unrolled loop corresponds to two or more iterations of the original loop the number of branch instructions executed is proportionately reduced When a loop is unrolled completely the loop s branch overhead is eliminated altogether In PVF this option is accessed using the Loop Unroll Count property in the Fortran Optimization property page Loop unrolling may be beneficial for the instruction scheduler When a loop is completely unrolled or unrolled two or more times opportunities for improved scheduling may be present
267. ugh gauge 97 levels n A level number which represents the number of function calling levels to be inlined The default number is one 1 Using a level greater than one indicates that function calls within inlined functions may be replaced with inlined code This allows the function inliner to automatically perform a sequence of inline and extract processes lib file ext A library file name This instructs the inliner to inline the functions within the library file file ext Create the library file using the Mextract option If no inline library is specified functions are extracted from a temporary library created during an extract prepass If you specify both a function name and a size n the compiler inlines functions that match the function name or have n or fewer statements If a keyword name lib or size is omitted then a name with a period is assumed to be an inline library a number is assumed to be a size and a name without a period is assumed to be a function name In the following example the compiler inlines functions with fewer than approximately 100 statements in the source file myprog f and writes the executable code in the default output file a out pgf95 Minline size 100 myprog f Refer to Chapter 4 Command Line Options for more information on the Minline options 5 1 1 Using an Inline Library If you specify one or more inline libraries on the command line with the Minline option the c
268. uments that you do not specify the defaults are as follows nobackslash noiomutex nodclchk noonetrip nodefaultunit nosave nodlines nounixlogical dollar noupcase M lt pgflag gt Syntax Mcache_align Optimization Controls Align unconstrained objects of length greater than or equal to 16 bytes on cache line boundaries An unconstrained object is a data object that is not a member of an aggregate structure or common block This option does not affect the alignment of allocatable or automatic arrays cache_align Note To effect cache line alignment of stack based local variables the main program or function must be compiled with Mcache_align Mconcur option option Instructs the compiler to enable auto concurrentization of loops If Command Line Options Mconcur is specified multiple processors will be used to execute loops that the compiler determines to be parallelizable Where option is one of the following noJaltcode n Instructs the parallelizer to generate alternate serial code for parallelized loops If altcode is specified without arguments the parallelizer determines an appropriate cutoff length and generates serial code to be executed whenever the loop count is less than or equal to that length If altcode n is specified the serial altcode is executed whenever the loop count is less than or equal to n If noaltcode is specified the parallelized version of the loop is always executed regardless of
269. unction The allowable built in functions are VAL REF LOC and FILL One was encountered that did not match one of these allowed forms 052 Illegal argument to VAL or LOC 053 SREF or VAL not legal in this context The built in functions REF and VAL can only be used as actual parameters in procedure calls W054 Implicit character used in a previous implicit statement An implicit character has been given an implied data type more than once The implied data type for the implicit character is changed anyway w055 Multiple implicit none statements The IMPLICIT NONE statement can occur only once in a subprogram w056 Implicit type declaration The dclchk switch and an implicit declaration following an IMPLICIT NONE statement will produce a warning message for IMPLICIT statements S057 Illegal equivalence of dummy variable Dummy arguments may not appear in EQUIVALENCE statements S058 Equivalenced variables and not in same common block A common block variable must not be equivalenced with a variable in another common block 059 Conflicting equivalence between and The indicated equivalence implies a storage layout inconsistent with other equivalences 060 Illegal equivalence of structure variable Messages 181 STRUCTURE and UNION variables may not appear in EQUIVALENCE statements S061 Equivalence of and extends common block backwards W062 Equivalence forces to be unaligned EQUIVALE
270. upports a variety of project types Console Application An application that runs in a console window using text input and output e Dynamic Library An executable file that provides routines that can be loaded on demand when called by the program that needs them e Static Library An archive file containing one or more object files that can be linked to create an executable e Windows Application An application that supports a graphical user interface that makes use of components like windows dialog boxes menus and so on The name of the program entry point for such applications is WinMain e Empty Project A skeletal project intended to allow migration of existing applications to PVF To create a new project select File New Project from the File menu The New Project dialog will appear In the left hand pane of the dialog select PGI Visual Fortran The right hand pane will display icons corresponding to the project types listed above Note that on x64 systems 32 bit and 64 bit project types are clearly labeled and they may be filtered using the 32 bit and 64 bit folders in the left hand navigation pane of the dialog Name the project in the edit box labeled Name and select where to create the project in the edit box labeled Location Double click the project type icon corresponding to the project type you want to create and the project will be created Look in the Solution Explorer select View Solution Explorer if not visible to see the
271. usually valid to parallelize timing loops to do so would distort the timing information for the inner loops 3 6 2 3 Scalars Quite often scalars will inhibit parallelization of non innermost loops There are two separate cases that present problems In the first case scalars appear to be expandable but appear in non innermost loops as in the following example do 1 j xX c i j 1 continue There are a number of technical problems to be resolved in order to recognize expandable scalars in non innermost loops Until this generalization occurs scalars like x above will inhibit parallelization of loops in which they are assigned In the following example scalar k is not expandable and it is not an accumulator for a reduction 38 Optimization amp Parallelization 2 AE 4 sgt n 2 keen 2 n 2 3 continue If the outer loop is parallelized conflicting values will be stored into k by the various processors The variable k cannot be made local to each processor because the value of k must remain coherent among the processors It is possible the loop could be parallelized if all assignments to k are placed in critical sections However it is not clear where critical sections should be introduced because in general the value for k could depend on another scalar or on k itself and code to obtain the value of other scalars must reside in the same critical section In the example above the assignment to k within a conditional
272. utine with variable parameters must use the va_start macro to set up a data structure before the parameters can be used The va_arg macro must be used to access the successive parameters C Parameter Conversion In C for a called prototyped function the parameter type in the called function must match the argument type in the calling function If the called function is not prototyped the calling convention uses the types of the arguments but promotes char or short to int and unsigned char or unsigned short to unsigned int and promotes float to double unless you use the Msingle option For more 156 Run time Environment information on the Msingle option refer to Chapter 3 If the called function is prototyped the unused bits of a register containing a char or short parameter are undefined and the called function must extend the sign of the unused bits when needed Calling Assembly Language Programs Example A 1 C Program Calling an Assembly language Routine File testmain c main long 1 paral 0x3 800000 float f para2 1 0 double d_para3 0 5 float return extern float sum_3 long paral float para2 double para3 Z return sum_3 1 paral f _para2 d_para3 j printf Parameter one type long 08x n 1 paral printf Parameter two type float f n f para2 printf Parameter three type double Sonn d_para3 printf The sum after conversion f n f return File sum_3 s
273. uting driver If a full pathname is supplied that file is used for the driver configuration file Syntax rc path filename Where path is either a relative pathname relative to the value of DRIVER or a full pathname beginning with Filename is the driver configuration file Default The driver uses the configuration file pgirc Usage In the following example the file pgf95rctest relative to usr pgi linux86 bin the value of DRIVER is the driver configuration file Command Line Options 91 pgf95 rc pgf95rctest myprog f Cross reference show S Stops compilation after the compiling phase and writes the assembly language output to the file filename s where the input file is filename f Default The compiler produces an executable file Usage In this example pgf95 produces the file myprog s in the current directory pgf95 S myprog f Cross reference c P F Mkeepasm o show Produce driver help information describing the current driver configuration Usage In the following example the driver displays configuration information to the standard output after processing the driver configuration file pgf95 show myprog f Cross reference V v help rc silent Do not print warning messages Usage In the following example the driver does not display warning messages pgf95 silent myprog f Cross reference v V w time Print execution times
274. ution It directs the compiler to create an executable in which the statements between PARALLEL and END PARALLEL are executed by multiple lightweight threads The code that lies between PARALLEL and END PARALLEL is called a parallel region 104 OpenMP Directives for Fortran The OpenMP parallelization directives support a fork join execution model in which a single thread executes all statements until a parallel region is encountered At the entrance to the parallel region a system dependent number of symmetric parallel threads begin executing all statements in the parallel region redundantly These threads share work by means of work sharing constructs such as parallel DO loops see below The number of threads in the team is controlled by the OMP_NUM_THREADS environment variable If OMP_NUM_THREADS is not defined the program will execute parallel regions using only one processor Branching into or out of a parallel region is not supported All other shared memory parallelization directives must occur within the scope of a parallel region Nested PARALLEL END PARALLEL directive pairs are not supported and are ignored The END PARALLEL directive denotes the end of the parallel region and is an implicit barrier When all threads have completed execution of the parallel region a single thread resumes execution of the statements that follow NOTE By default there is no work distribution in a parallel region Each active thread executes the
275. ve this register value for its caller Run time Environment 151 Joeax esi edi Joecx Yoedx st 0 st 1 Gerti EFLAGS Integral and pointer return values appear in eax A function that returns a structure or union value places the address of the result in eax Otherwise this is a scratch register These local registers have no specified role in the standard calling sequence Functions must preserve their values for the caller Scratch registers have no specified role in the standard calling sequence Functions do not have to preserve their values for the caller Floating point return values appear on the top of the floating point register stack there is no difference in the representation of single or double precision values in floating point registers If the function does not return a floating point value then the stack must be empty Floating point scratch registers have no specified role in the standard calling sequence These registers must be empty before entry and upon exit from a function The flags register contains the system flags such as the direction flag and the carry flag The direction flag must be set to the forward i e zero direction before entry and upon exit from a function Other user flags have no specified role in the standard calling sequence and are not reserved Floating Point Control Word The control word contains the floating point flags such as the rounding mode and exc
276. ved message number gt Messages 199 267 W268 W269 lt reserved message number gt Cannot inline subprogram common block mismatch Cannot inline subprogram argument type mismatch This message may be Severe if have gone too far to undo inlining process F270 W271 1272 273 F274 275 F276 I277 278 W279 200 Missing exlib option Can t inline wrong number of arguments Argument of inlined function not used Inline library not specified on command line inlib switch Unable to access file TOC Unable to open file while extracting or inlining Assignment to constant actual parameter in inlined subprogram Inlining of function may result in recursion lt reserved message number gt Possible use of before definition in Messages The optimizer has detected the possibility that a variable is used before it has been assigned a value The names of the variable and the function in which the use occurred are listed The line number if specified is the line number of the basic block containing the use of the variable W280 Syntax error in directive messages 280 300 rsvd for directive handling W281 Directive ignored S300 Too few data constants in initialization of derived type S301 must be TEMPLATE or PROCESSOR S302 Unmatched ENDS statement S303 END statement for required in an interface block 304 EXIT CYCLE statement must appear in a DO DOWHIL
277. verse order i e the rightmost argument in C call syntax has the highest address A dummy word may be pushed ahead of the rightmost argument in order to preserve doubleword alignment All incoming arguments appear on the stack residing in the stack frame of the caller e An argument size is increased if necessary to make it a multiple of words This may require tail padding depending on the size of the argument All registers on an x86 system are global and thus visible to both a calling and a called function Registers ebp ebx edi Gest and esp are non volatile across function calls Therefore a function must preserve these registers values for its caller Remaining registers are volatile scratch If a calling function wants to preserve such a register value across a function call it must save its value explicitly Some registers have assigned roles in the standard calling sequence Joesp The stack pointer holds the limit of the current stack frame which is the address of the stack s bottom most valid word At all times the stack pointer should point to a word aligned area ebp The frame pointer holds a base address for the current stack frame Consequently a function has registers pointing to both ends of its frame Incoming arguments reside in the previous frame referenced as positive offsets from ebp while local variables reside in the current frame referenced as negative offsets from ebp A function must preser
278. wer and upper bounds and its dimension For example PGFTN F Subscript out of range for array a a f 2 subscript 3 lower bound 1 upper bound 2 dimension 2 81 Mnobounds Mbyteswapio Mchkfpstk Mchkptr Mchkstk disables array bounds checking swap byte order from big endian to little endian or vice versa upon input output of Fortran unformatted data files instructs the compiler to check for internal consistency of the x87 floating point stack in the prologue of a function and after returning from a function or subroutine call Floating point stack corruption may occur in many ways one of which is Fortran code calling floating point functions as subroutines Oe with the CALL statement If the PGI_CONTINUE environment variable is set upon execution of a program compiled with Mchkfpstk the stack will be automatically cleaned up and execution will continue There is a performance penalty associated with the stack cleanup If PGI_LCONTINUE is set to verbose the stack will be automatically cleaned up and execution will continue after printing of a warning message instructs the compiler to check for pointers that are de referenced while initialized to NULL instructs the compiler to check the stack for available space in the prologue of a function and before the start of a parallel region Prints a warning message and aborts the program gracefully if stack space is insufficient Useful when many local and private va
279. ws PGI provides performance instrumentation that measures time at the function level and the source line level To instrument a program for performance profiling select the desired Profiling property in both the Fortran General and the Linker General property pages then rebuild the program Run the program either using the Debug Start Without Debugging menu selection or manually from the command line Program execution will create a pgprof out file in the working directory of the program Next select Start Al Programs PGI Visual Fortran PGI Visual Fortran Tools PGPROF Performance Profiler to launch PGPROF Open the pgprof out file located in the directory where the program was run and examine the results Use the PGPROF online help accessed via the PGPROF Help menu for more details on using the profiler 1 13 VC Interoperability If Visual C is installed along with PVF Visual Studio solutions containing both PVF and VC projects can be created Each project though must be purely PVF or VC Fortran and C C code cannot be mixed in a single project This constraint is purely an organizational issue Fortran subprograms may call C functions and C functions may call Fortran subprograms as outlined in Chapter 10 Inter language Calling Note that calling Visual C as opposed to C from Fortran is very complicated and not recommended Getting Started with PVF 9 1 14 Using PVF Online Help PVF online help is fully int
280. ype The indicated variable is used in a context which requires a variable of some other data type S095 Expression has wrong data type An expression of some data type appears in a context which requires an expression of some other data type 096 Illegal complex comparison The relations LT GT GE and LE are not allowed for complex values S097 Statement label has been defined more than once More than one statement with the indicated statement number occurs in the subprogram S098 Divide by zero 099 Illegal use of Aggregate record references may only appear in aggregate assignment statements unformatted I O statements and as parameters to subprograms They may not appear for example in expressions Also records with differing structure types may not be assigned to one another 100 Expression cannot be promoted to a vector An expression was used that required a scalar quantity to be promoted to a vector illegally For example the assignment of a character constant string to a character array Records too cannot be promoted to vectors 101 Vector operation not allowed on Record and character typed entities may only be referenced as scalar quantities 102 Arithmetic IF expression has wrong data type The parenthetical expression of an arithmetic if statement must be an integer real or double precision scalar expression 103 Type conversion of subscript expression for The data type of a subsc
281. yprog f Cross reference m S V v Command Line Options 85 module lt moduledir gt Use the module option to specify a particular directory in which generated intermediate mod files should be placed If the module lt moduledir gt option is present and USE statements are present in a compiled program unit lt moduledir gt will search for mod intermediate files prior to the search in the default local directory Default The compiler places mod files in the current working directory and searches only in the current working directory for pre compiled intermediate mod files Usage The following command line requests that any intermediate module file produced during compilation of myprog f be placed in the directory mymods in particular the file mymods myprog mod will be used pgf95 module mymods myprog f To set this option in PVF use the Fortran Output Module Path property mp align no numa Use the mp option to instruct the compiler to interpret user inserted OpenMP shared memory parallel programming directives and generate an executable file which will utilize multiple processors in a shared memory parallel system See OpenMP Directives for Fortran for a detailed description of this programming model and the associated directives and pragmas The align sub option forces loop iterations to be allocated to OpenMP processes using an algorithm that maximizes alignment of vector sub sections in loo

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