pgi62_flags
PGI 6.2 Compilers for Linux Optimization, Compiler, and Other flags for use by SPEC CPU2006
The PGI C compiler.
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pgcc
The PGI C++ compiler.
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pgCC
The PGI Fortran 90/95 compiler.
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pgf90
Disable warning messages.
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-w
Don't include Fortran main program object module.
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-Mnomain
Use C99 language features.
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-c9x
Chooses generally optimal flags for the target platform.
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-fast
Chooses generally optimal flags for a processor that supports SSE capabillity.
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-fastsse
Disable C++ exception handling support.
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--no_exceptions
Disable C++ run time type information support.
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--no_rtti
Align "unconstrained" data objects of size greater than or equal to 16
bytes on cache-line boundaries. An "unconstrained" object is a variable or
array that is not a member of an aggregate structure or common block, is not
allocatable, and is not an automatic array. On by default on 64-bit Linux systems.
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-Mcache_align
Set SSE to flush-to-zero mode; if a floating-point underflow occurs, the value is set to zero.
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-Mflushz
Treat denormalized numbers as zero. Included with "-fastsse" on Intel based systems. For AMD based systems, "-Mdaz" is
not included by default with "-fastsse".
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-Mdaz
Generate code to set up a stack frame.
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-Mframe
Eliminates operations that set up a true stack frame pointer for every function. With this option enabled, you
cannot perform a traceback on the generated code and you cannot access local variables.
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-Mnoframe
CPU2006 flags file rule used to split an optimization flag containing sub-options into multiple flag descriptions.
Please refer to the flag file rule of the various sub-options for the actual flag description.
Instructs the compiler to use relaxed precision in the calculation of reciprocal square root (1/sqrt). Can result in
improved performance at the expense of numerical accuracy.
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-Mfprelaxed=rsqrt
Instructs the compiler to use relaxed precision in the calculation of square root. Can result in
improved performance at the expense of numerical accuracy.
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-Mfprelaxed=sqrt
Instructs the compiler to use relaxed precision in the calculation of divides. Can result in
improved performance at the expense of numerical accuracy.
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-Mfprelaxed=div
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. The default on an AMD system is "-Mfprelaxed=rsqrt". The
default on an Intel system is "-Mfprelaxed=rsqrt,sqrt,div"
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-Mfprelaxed
CPU2006 flags file rule used to split an optimization flag containing sub-options into multiple flag descriptions.
Please refer to the flag file rule of the various sub-options for the actual flag description.
Set the fetch-ahead distance for prefetch instructions to m cache lines
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-Mprefetch=d:m
Set maximum number of prefetch instructions to generate for a given loop to p.
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-Mprefetch=n:p
Use the prefetchnta instruction.
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-Mprefetch_nta
Use the prefetch instruction.
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-Mprefetch=plain
Use the prefetcht0 instruction.
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-Mprefetch=t0
Use the AMD-specific prefetchw instruction.
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-Mprefetch=w
Enable generation of prefetch instructions on processors where they are supported.
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-Mprefetch
Disable generation of prefetch instructions.
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-Mnoprefetch
Use SSE/SSE2 instructions to perform scalar floating-point arithmetic on targets where these
instructions are supported.
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-Mscalarsse
Do not use SSE/SSE2 instructions to perform scalar floating-point arithmetic; use x87 operations instead.
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-Mnoscalarsse
Instructs the compiler to extend the sign bit that is set as a result of an object's conversion from one
data type to an object of a larger signed data type.
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-Msignextend
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.
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-Mlre_array
Allow expression re-association; specifying this sub-option can increase opportunities for loop-carried
redundancy elimination.
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-Mlre=assoc
Disable expression re-association.
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-Mlre=noassoc
Enables loop-carried redundancy elimination, an optimization that can reduce the number of arithmetic operations
and memory references in loops.
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-Mlre
Disable loop-carried redundancy elimination.
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-Mnolre
Instructs the compiler not to perform idiom recognition or introduce calls to hand-optimized vector functions.
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-Mnovintr
Generate profile-feedback instrumentation (PFI); this includes extra code to collect run-time statistics and dump
them to a trace file for use in a subsequent compilation. PFI gathers information about a program's execution and data values
but does not gather information from hardware performance counters. PFI does gather data for optimizations which are unique to profile-feedback optimization.
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-Mpfi
Enable profile-feedback optimizations.
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-Mpfo
CPU2006 flags file rule used to split an optimization flag containing sub-options into multiple flag descriptions.
Please refer to the flag file rule of the various sub-options for the actual flag description.
Interprocedural Analysis option: Recognize when targets of pointer dummy are aligned.
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-Mipa=align
Interprocedural Analysis option: Disable recognizition when targets of pointer dummy are aligned.
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-Mipa=noalign
Interprocedural Analysis option: Remove arguments replaced by -Mipa=ptr,const
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-Mipa=arg
Interprocedural Analysis option: Do not remove arguments replaced by -Mipa=ptr,const
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-Mipa=noarg
Interprocedural Analysis option: Generate call graph information for pgicg tool.
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-Mipa=cg
Interprocedural Analysis option: Do not generate call graph information for pgicg
tool.
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-Mipa=nocg
Interprocedural Analysis option: Enable interprocedural constant propagation.
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-Mipa=const
Interprocedural Analysis option: Disable interprocedural constant propagation.
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-Mipa=noconst
Interprocedural Analysis option: Used with -Mipa=inline to specify functions which should not be inlined.
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-Mipa=except:func
Instructs the compiler to perform interprocedural analysis. Equivalant to -Mipa=align,arg,const,f90ptr,shape,globals,libc,localarg,ptr,pure.
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-Mipa=fast
Interprocedural Analysis option: Force all objects to recompile regardless
whether IPA information has changed.
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-Mipa=force
Interprocedural Analysis option: Optimize references to global values.
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-Mipa=globals
Interprocedural Analysis option: Do not optimize references to global values.
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-Mipa=noglobals
Interprocedural Analysis option: Automatically determine which functions
to inline, limit to n levels. IPA-based function inlining is performed from leaf
routines upward.
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-Mipa=inline:n
Interprocedural Analysis option: Automatically determine which functions to inline.
IPA-based function inlining is performed from leaf routines upward.
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-Mipa=inline
Interprocedural Analysis option: Allow inlining of routines from libraries.
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-Mipa=libinline
Interprocedural Analysis option: Do not inline routines from libraries.
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-Mipa=nolibinline
Interprocedural Analysis option: Used to optimize calls to certain functions in the system standard C library, libc.
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-Mipa=libc
Interprocedural Analysis option: Allow recompiling and optimization of routines from libraries using IPA information.
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-Mipa=libopt
Interprocedural Analysis option: Don't optimize routines in libraries.
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-Mipa=nolibopt
Interprocedural Analysis option: -Mipa=arg plus externalizes local pointer targets.
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-Mipa=localarg
Interprocedural Analysis option: -Mipa=arg plus externalizes local pointer targets.
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-Mipa=localarg
Interprocedural Analysis option: Do not externalize local pointer targets.
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-Mipa=nolocalarg
Interprocedural Analysis option: Enable pointer disambiguation across procedure calls.
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-Mipa=ptr
Interprocedural Analysis option: Disable pointer disambiguation.
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-Mipa=noptr
Interprocedural Analysis option: Fortran 90/95 Pointer disambiguation across calls.
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-Mipa=f90ptr
Interprocedural Analysis option: Disable Fortran 90/95 pointer disambiguation
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-Mipa=nof90ptr
Interprocedural Analysis option: Pure function detection.
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-Mipa=pure
Interprocedural Analysis option: Disable pure function detection.
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-Mipa=nopure
Interprocedural Analysis option: Perform Fortran 90 array shape propagation.
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-Mipa=shape
Interprocedural Analysis option: Disable Fortran 90 array shape propagation.
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-Mipa=noshape
Interprocedural Analysis option: Remove functions that are never called.
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-Mipa=vestigial
Interprocedural Analysis option: Do not remove functions that are never called.
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-Mipa=novestigial
Enable Interprocedural Analysis.
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-Mipa
CPU2006 flags file rule used to split an optimization flag containing sub-options into multiple flag descriptions.
Please refer to the flag file rule of the various sub-options for the actual flag description.
Instructs the parallelizer to generate alternate serial code for parallelized loops. 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.
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-Mconcur=altcode
Instructs the parallelizer to generate alternate serial code for parallelized loops. With arguments, the serial altcode
is executed whenever the loop count is less than or equal to n.
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-Mconcur=altcode:n
Always execute the parallelized version of a loop regardless of the loop count.
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-Mconcur=noaltcode
Disables parallelization of loops with reductions.
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-Mconcur=noassoc
Assume loops containing calls are safe to parallelize and allows loops containing calls to be
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.
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-Mconcur=cncall
Do not assume loops containing calls are safe to parallelize.
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-Mconcur=nocncall
Parallelize with block distribution. Contiguous blocks of iterations of a parallelizable loop
are assigned to the available processors.
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-Mconcur=dist:bloc
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.
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-Mconcur=dist:cyclic
Enable parallelization of innermost loops.
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-Mconcur=innermost
Disable parallelization of innermost loops.
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-Mconcur=noinnermost
Instructs the compiler to enable auto-concurrentization of loops. If -Mconcur is specified, multiple processors
will be used to execute loops that the compiler determines to be parallelizable.
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-Mconcur
CPU2006 flags file rule used to split an optimization flag containing sub-options into multiple flag descriptions.
Please refer to the flag file rule of the various sub-options for the actual flag description.
Instructs the inliner to inline the functions within the library filename.ext.
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-Minline=lib:filename.ext
Instructs the inliner to inline all eligible functions except func, a function in the source text.
Multiple functions can be listed, comma-separated.
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-Minline=except:func
Instructs the inliner to inline function func.
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-Minline=name:func
Instructs the inliner to inline functions with n or fewer statements.
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-Minline=size:n
Instructs the inliner to perform n levels of inlining.
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-Minline=levels:n
Instructs the inliner to perform 1 level of inlining.
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-Minline
Adds a call to the routine "mallopt" in the main routine. This option can have a dramatic impact on the performance of programs that dynamically allocate memory, especially for those which have a few large mallocs. To be effective, this switch must be specified when compiling the file containing the Fortran, C, or C++ main routine. This is currently only effective on 64-bit Linux systems.
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-Msmartalloc
CPU2006 flags file rule used to split an optimization flag containing sub-options into multiple flag descriptions.
Please refer to the flag file rule of the various sub-options for the actual flag description.
Assume all pointers and arrays are independent and safe for aggressive optimizations,
and in particular that no pointers or arrays overlap of conflict with each other.
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-Msafeptr=all
Instructs the compiler that arrays and pointers are treated with the same copyin and copyout
semantics as Fortran dummy arguments.
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-Msafeptr=arg
Instructs the compiler that local pointers and arrays do not overlap or
conflict with each other and are independent.
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-Msafeptr=auto
Instructs the compiler that local pointers and arrays do not overlap or
conflict with each other and are independent.
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-Msafeptr=local
Instructs the compiler that static pointers and arrays do not overlap or conflict
with each other and are independent.
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-Msafeptr=static
Instructs the compiler that global or external pointers and arrays do not overlap or
conflict with each other and are independent.
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-Msafeptr=global
Instructs the C/C++ compiler to override data dependencies between pointers of a given storage class.
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-Msafeptr
CPU2006 flags file rule used to split an optimization flag containing sub-options into multiple flag descriptions.
Please refer to the flag file rule of the various sub-options for the actual flag description.
Instructs the compiler to completely unroll loops with a constant loop count of less than
or equal to m.
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-Munroll=c:m
Instructs the compiler to unroll u times, a loop that is not completely unrolled, or has a
non-constant loop count.
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-Munroll=n:u
Invokes the loop unroller.
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-Munroll
Disable loop unrolling.
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-Mnounroll
Enable an optional post-pass instruction scheduling.
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-Msmart
Disable an optional post-pass instruction scheduling.
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-Mnosmart
CPU2006 flags file rule used to split an optimization flag containing sub-options into multiple flag descriptions.
Please refer to the flag file rule of the various sub-options for the actual flag description.
Disable automatic vector pipelining.
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-Mnovect
Instructs the vectorizer to generate alternate code 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
- Altcode base on array alignments calculated dynamically at runtime.
The compiler also determines suitable loop count and array alignment conditions for executing the altcode.
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-Mvect=altcode
Disables alternate code generation for vectorized loops.
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-Mvect=noaltcode
Instructs the vectorizer to enable certain associativity conversions that can change the results of a computations due to roundoff error. A typical optimization is to change an arithmetic operation to an arithmetic opteration that is mathmatically correct, but can be computationally different, due to round-off error.
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-Mvect=assoc
Instructs the vectorizer to disable associativity conversions.
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-Mvect=noassoc
Instructs the vectorizer, when performing cache tiling optimizations, to assume a cache size of n.
The default size is n=262144.
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-Mvect=cachesize:n
Instructs the vectorizer to enable loop fusion.
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-Mvect=fuse
Instructs the vectorizer to enable idiom recognition.
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-Mvect=idiom
Generate vector loops 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 exceed a certain threshold.
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-Mvect=nosizelimit
Instructs the vectorizer to generate prefetch instructions.
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-Mvect=prefetch
Instructs the vectorizer to search for vectorizable loops and, where possible, make use of
SSE, SSE2, and prefetch instructions.
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-Mvect=sse
Enable automatic vector pipelining.
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-Mvect
Disables -Ktrap=fp.
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-Mnofptrap
-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 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 -Ktrap=inv,divz,ovf.
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-Ktrap=fp
Enable long branches.
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-Mlongbranch
Link with the AMD Core Math Library. Available from www.amd.com
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-lacml
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.
When used strictly as a linker flag, the PGI OpenMP runtime will be linked and users can use the environment variables MP_BIND and MP_BLIST to bind a serial program to a CPU.
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-mp
The align sub-option to -mp forces loop iterations to be allocated to OpenMP processes using an algorithm that maximizes alignment of vector sub-sections in loops 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.
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-mp=align
The numa suboption to -mp uses libnuma on systems where it is available.
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-mp=numa
The nonuma suboption to -mp tells the driver to not link with libnuma.
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-mp=nonuma
(For use only on 64-bit Linux targets) Generate code for the medium memory model in the linux86-64 execution environment. The default small memory model of the linux86-64 environment limits the combined area for a user's object or executable to 1GB, with the Linux kernel managing usage of the second 1GB of address for system routines, shared libraries, stacks, etc. Programs are started at a fixed address, and the program can use a single instruction to make most memory references. The medium memory model allows for larger than 2GB data areas, or .bss sections. Program units compiled using either -mcmodel=medium or -fpic require additional instructions to reference memory. The effect on performance is a function of the data-use of the application. The -mcmodel=medium switch must be used at both compile time and link time to create 64-bit executables. Program units compiled for the default small memory model can be linked into medium memory model executables as long as they are compiled -fpic, or position-independent.
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-mcmodel=medium
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.
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-Mlarge_arrays
Set the optimization level to -O2
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-O
A basic block is generated for each C statement. No scheduling is done
between statements. No global optimizations are performed.
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-O0
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:
- Algebraic identity removal
- Constant folding
- Common subexpression elimination
- Local register optimization
- Peephole optimizations
- Redundant load and store elimination
- Strength reductions
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-O1
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 loops, 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:
- Branch to branch elimination
- Constant propagation
- Copy propagation
- Dead store elimination
- Global register allocation
- Invariant code motion
- Induction variable elimination
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-O2
All level 1 and 2 optimizations are performed.
In addition, this level enables more aggressive code hoisting and scalar replacement optimizations that may or may not be profitable.
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-O3
Same as "-O3".
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-O4
Specify the type of the target processor as AMD64 Processor 32-bit mode.
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-tp k8-32
Specify the type of the target processor as AMD64 Processor 64-bit mode.
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-tp k8-64
Specify the type of the target processor as Intel P7 Architecture with
EM64t, 64-bit mode.
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-tp p7-64
Specify the type of the target processor as Intel P7 Architecture (Pentium
4, Xeon, Centrino).
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-tp p7
Specify the type of the target processor as Intel Core 2 EM64T or compatible architecture using 64-bit mode.
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-tp core2-64
Specify the type of the target processor as Intel Core 2 or compatible architecture using 32-bit mode.
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-tp core2
Use the unified AMD/Intel 64-bit mode.
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-tp x64