Lenovo-OMP2012-Rome7742-20190711.xml
SPEC OMP2012 Flag Description for the Intel(R) C/C++ Compiler
for IA32 and Intel 64 applications and Intel(R) Fortran Compiler for IA32 and Intel 64
applications
Open MP Tuning Flags
KMP_AFFINITY
The KMP_AFFINITY environment variable uses the following general syntax:
Syntax
|
KMP_AFFINITY=[<modifier>,...]<type>[,<permute>][,<offset>]
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For example, to list a machine topology map, specify KMP_AFFINITY=verbose,none to use a modifier of verbose and a type of none.
The following table describes the supported specific arguments.
Argument |
Default
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Description
|
modifier
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noverbose
respect
granularity=core
|
Optional. String consisting of keyword and specifier.
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type
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none
|
Required string. Indicates the thread affinity to use.
-
compact
-
disabled
-
explicit
-
none
-
scatter
-
logical (deprecated; instead use compact, but omit any permute value)
-
physical (deprecated; instead use scatter, possibly with an offset value)
The logical and physical types are deprecated but supported for backward compatibility.
|
permute
|
0
|
Optional. Positive integer value. Not valid with type values of explicit, none, or disabled. |
offset
|
0
|
Optional. Positive integer value. Not valid with type values of explicit, none, or disabled.
|
Affinity Types
Type is the only required argument.
type = none (default)
Does not bind OpenMP threads to particular thread contexts; however, if the operating system supports affinity, the compiler still uses the OpenMP thread affinity interface to determine machine topology. Specify KMP_AFFINITY=verbose,none to list a machine topology map.
type = compact
Specifying compact assigns the OpenMP thread <n>+1 to a free thread context as close as possible to the thread context where the <n> OpenMP thread was placed. For example, in a topology map, the nearer a node is to the root, the more significance the node has when sorting the threads.
type = disabled
Specifying disabled completely disables the thread affinity interfaces. This forces the OpenMP run-time library to behave as if the affinity interface was not supported by the operating system. This includes the low-level API interfaces such as kmp_set_affinity and kmp_get_affinity, which have no effect and will return a nonzero error code.
type = explicit
Specifying explicit assigns OpenMP threads to a list of OS proc IDs that have been explicitly specified by using the proclist= modifier, which is required for this affinity type.
type = scatter
Specifying scatter distributes the threads as evenly as possible across the entire system. scatter is the opposite of compact; so the leaves of the node are most significant when sorting through the machine topology map.
Deprecated Types: logical and physical
Types logical and physical are deprecated and may become unsupported in a future release. Both are supported for backward compatibility.
For logical and physical affinity types, a single trailing integer is interpreted as an offset specifier instead of a permute specifier. In contrast, with compact and scatter types, a single trailing integer is interpreted as a permute specifier.
Specifying logical assigns OpenMP threads to consecutive logical processors, which are also called hardware thread contexts. The type is equivalent to compact, except that the permute specifier is not allowed. Thus, KMP_AFFINITY=logical,n is equivalent to KMP_AFFINITY=compact,0,n (this equivalence is true regardless of the whether or not a granularity=fine modifier is present).
Permute and offset combinations
For both compact and scatter, permute and offset are allowed; however, if you specify only one integer, the compiler interprets the value as a permute specifier. Both permute and offset default to 0.
The permute specifier controls which levels are most significant when sorting the machine topology map. A value for permute forces the mappings to make the specified number of most significant levels of the sort the least significant, and it inverts the order of significance. The root node of the tree is not considered a separate level for the sort operations.
The offset specifier indicates the starting position for thread assignment.
Modifier Values for Affinity Types
Modifiers are optional arguments that precede type. If you do not specify a modifier, the noverbose, respect, and granularity=core modifiers are used automatically.
Modifiers are interpreted in order from left to right, and can negate each other. For example, specifying KMP_AFFINITY=verbose,noverbose,scatter is therefore equivalent to setting KMP_AFFINITY=noverbose,scatter, or just KMP_AFFINITY=scatter.
modifier = noverbose (default)
Does not print verbose messages.
modifier = verbose
Prints messages concerning the supported affinity. The messages include information about the number of packages, number of cores in each package, number of thread contexts for each core, and OpenMP thread bindings to physical thread contexts.
Information about binding OpenMP threads to physical thread contexts is indirectly shown in the form of the mappings between hardware thread contexts and the operating system (OS) processor (proc) IDs. The affinity mask for each OpenMP thread is printed as a set of OS processor IDs.
KMP_LIBRARY
The serial mode forces parallel applications to run on a single processor.
KMP_LIBRARY = { throughput | turnaround | serial },
Selects the OpenMP run-time library execution mode.
The options for the variable value are throughput, turnaround, and serial.
Execution modes
The compiler with OpenMP enables you to run an application under different
execution modes that can be specified at run time. The libraries support
the serial, turnaround, and throughput modes.
Serial
Turnaround
In a dedicated (batch or single user) parallel environment where all
processors are exclusively allocated to the program for its entire run,
it is most important to effectively utilize all of the processors all
of the time. The turnaround mode is designed to keep active all of the
processors involved in the parallel computation in order to minimize the
execution time of a single job. In this mode, the worker threads actively
wait for more parallel work, without yielding to other threads.
Avoid over-allocating system resources. This
occurs if either too many threads have been specified, or if too few processors
are available at run time. If system resources are over-allocated, this
mode will cause poor performance. The throughput mode should be used instead
if this occurs.
Throughput
In a multi-user environment where the load on the parallel machine is
not constant or where the job stream is not predictable, it may be better
to design and tune for throughput. This minimizes the total time to run
multiple jobs simultaneously. In this mode, the worker threads will yield
to other threads while waiting for more parallel work.
The throughput mode is designed to make the program aware of its environment
(that is, the system load) and to adjust its resource usage to produce
efficient execution in a dynamic environment. This mode is the default.
KMP_BLOCKTIME
KMP_BLOCKTIME = value.
Sets the time, in milliseconds, that a thread should wait, after completing
the execution of a parallel region, before sleeping.Use the optional
character suffixes: s (seconds), m (minutes), h (hours), or d (days)
to specify the units.Specify infinite for an unlimited wait time.
KMP_STACKSIZE
KMP_STACKSIZE = value.
Sets the number of bytes to allocate for each OpenMP* thread
to use as the private stack for the thread.
Recommended size is 16m.
Use the optional suffixes: b (bytes), k (kilobytes), m (megabytes),
g (gigabytes), or t (terabytes) to specify the units.
This variable does not affect the native operating system threads
created by the user program nor the thread executing the sequential
part of an OpenMP* program or parallel programs created using -parallel.
OMP_NUM_THREADS
Sets the maximum number of threads to use for OpenMP* parallel regions if no
other value is specified in the application. This environment variable
applies to both -openmp and -parallel.
Example syntax on a Linux system with 8 cores:
export OMP_NUM_THREADS=8
OMP_DYNAMIC
OMP_DYNAMIC={ 1 | 0 }
Enables (1, true) or disables (0,false) the dynamic adjustment of the number of threads.
OMP_SCHEDULE
OMP_SCHEDULE={ type,[chunk size]}
Controls the scheduling of the for-loop work-sharing construct.
type can be either of static,dynamic,guided,runtime
chunk size should be positive integer
OMP_NESTED
OMP_NESTED={ 1 | 0 }
Enables creation of new teams in case of nested parallel regions (1,true) or serializes (0,false) all nested parallel regions. Default is 0.
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Copyright © 2012 Intel Corporation. All Rights Reserved.
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Invoke the Intel C/C++ compiler for Intel 64 applications
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Invoke the Intel C/C++ compiler for 32-bit applications
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Invoke the Intel C compiler for IA32 applications.
You need binutils 2.16.91.0.7 or later with this compiler to support new instructions on Intel Core 2 processors
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Invoke the Intel C++ compiler for IA32 and Intel 64 applications.
You need binutils 2.16.91.0.7 or later with this compiler to support new instructions on Intel Core 2 processors
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Invoke the Intel Fortran compiler for IA32 and Intel 64 applications.
You need binutils 2.16.91.0.7 or later with this compiler to support new instructions on Intel Core 2 processors
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Compiler option to set the path for include files.
Used in some integer peak benchmarks which were built using the Intel 64-bit C++ compiler.
Compiler option to set the path for library files.
Used in some integer peak benchmarks which were built using the Intel 64-bit C++ compiler.
Compiler option to set the path for include files.
Used in some peak benchmarks which were built using the Intel 32-bit C++ compiler.
Compiler option to set the path for library files.
Used in some integer peak benchmarks which were built using the Intel 32-bit C++ compiler.
Compiler option to set the path for include files.
Used in some peak benchmarks which were built using the Intel 32-bit Fortran compiler.
Compiler option to set the path for library files.
Used in some integer peak benchmarks which were built using the Intel 32-bit Fortran compiler.
Defines a macro
Define the MPICH_IGNORE_CXX_SEEK macro at compilation stage to catastrophic error: "SEEK_SET is #defined but must not be for the C++ binding of MPI" when compiling C++ MPI application.
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For mixed-language benchmarks, tell the compiler to convert routine names to lowercase for compatibility
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For mixed-language benchmarks, tell the compiler to assume that routine names end with an underscore
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Tell the compiler to treat source files as C++ regardless of the file extension
specify source files are in free format. Same as -FR. -nofree indicates fixed format
specify source files are in fixed format. Same as -FI. -nofixed indicates free format
This option specifies that the main program is not written in Fortran.
It is a link-time option that prevents the compiler from linking for_main.o
into applications.
For example, if the main program is written in C and calls a Fortran subprogram,
specify -nofor-main when compiling the program with the ifort command.
If you omit this option, the main program must be a Fortran program.
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-mcmodel=<size>
use a specific memory model to generate code and store data
small - Restricts code and data to the first 2GB of address space (DEFAULT)
medium - Restricts code to the first 2GB; it places no memory restriction on data
large - Places no memory restriction on code or data
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enable language support for , as described below
c99 enable C99 support for C programs
c++11 enable C++11 experimental support for C++ programs
c++0x same as c++11
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Enables optimizations for speed and disables some optimizations that
increase code size and affect speed.
To limit code size, this option:
- Enables global optimization; this includes data-flow analysis,code motion, strength reduction and test replacement, split-lifetime analysis, and instruction scheduling.
- Disables intrinsic recognition and intrinsics inlining.
The O1 option may improve performance for applications with very large code size, many branches, and execution time not dominated by code within loops.
On IA-32 Windows platforms, -O1 sets the following:
/Qunroll0, /Oi-, /Op-, /Oy, /Gy, /Os, /GF (/Qvc7 and above),
/Gf (/Qvc6 and below), /Ob2, and /Og
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Enables optimizations for speed. This is the generally recommended
optimization level. This option also enables:
- Inlining of intrinsics
- Intra-file interprocedural optimizations, which include:
- inlining
- constant propagation
- forward substitution
- routine attribute propagation
- variable address-taken analysis
- dead static function elimination
- removal of unreferenced variables
- The following capabilities for performance gain:
- constant propagation
- copy propagation
- dead-code elimination
- global register allocation
- global instruction scheduling and control speculation
- loop unrolling
- optimized code selection
- partial redundancy elimination
- strength reduction/induction variable simplification
- variable renaming
- exception handling optimizations
- tail recursions
- peephole optimizations
- structure assignment lowering and optimizations
- dead store elimination
On IA-32 Windows platforms, -O2 sets the following:
/Og, /Oi-, /Os, /Oy, /Ob2, /GF (/Qvc7 and above), /Gf (/Qvc6
and below), /Gs, and /Gy.
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Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets. On IA-32
Windows platforms, -O3 sets the following:
/GF (/Qvc7 and above), /Gf (/Qvc6 and below), and /Ob2
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Tells the compiler the maximum number of times to unroll loops.
This option enables additional interprocedural optimizations for single
file compilation. These optimizations are a subset of full intra-file
interprocedural optimizations. One of these optimizations enables the
compiler to perform inline function expansion for calls to functions
defined within the current source file.
-ipo[n]
Multi-file ip optimizations that includes:
- inline function expansion
- interprocedural constant propogation
- dead code elimination
- propagation of function characteristics
- passing arguments in registers
- loop-invariant code motion
(n - number of multi-file objects)
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This option instructs the compiler to analyze and transform the program so that
64-bit pointers are shrunk to 32-bit pointers, and 64-bit longs (on Linux) are
shrunk into 32-bit longs wherever it is legal and safe to do so.
In order for this option to be effective the compiler must be able to optimize using
the -ipo/-Qipo option and must be able to analyze all library/external calls the program makes.
This option requires that the size of the program executable never exceeds 2^32 bytes and all
data values can be represented within 32 bits. If the program can run correctly in a 32-bit system,
these requirements are implicitly satisfied. If the program violates these size restrictions,
unpredictable behavior might occur.
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-scalar-rep enables scalar replacement performed during loop transformation.
To use this option, you must also specify O3. -scalar-rep- disables this optimization.
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This options tells the compiler to assume no aliasing in the program.
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enable floating point model variation
[no-]except - enable/disable floating point semantics
fast[=1|2] - enables more aggressive floating point optimizations
precise - allows value-safe optimizations
source - enables intermediates in source precision
strict - enables -fp-model precise -fp-model except, disables
contractions and enables pragma stdc fenv_access
double - rounds intermediates in 53-bit (double) precision
extended - rounds intermediates in 64-bit (extended) precision
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specify how data items are aligned
keywords: all (same as -align), none (same as -noalign),
[no]commons, [no]dcommons,
[no]qcommons, [no]zcommons,
rec1byte, rec2byte, rec4byte,
rec8byte, rec16byte, rec32byte,
array8byte, array16byte, array32byte,
array64byte, array128byte, array256byte,
[no]records, [no]sequence
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The -fast option enhances execution speed across the entire program
by including the following options that can improve run-time performance:
-O3 (maximum speed and high-level optimizations)
-ipo (enables interprocedural optimizations across files)
-xT (generate code specialized for Intel(R) Core(TM)2 Duo processors, Intel(R) Core(TM)2 Quad processors
and Intel(R) Xeon(R) processors with SSSE3)
-static (disable -prec-div)
Statically link in libraries at link time
-no-prec-div (disable -prec-div)
where -prec-div improves precision of FP divides (some speed impact)
To override one of the options set by /fast, specify that option after the
-fast option on the command line. The exception is the xT or QxT option
which can't be overridden. The options set by /fast may change from
release to release.
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Compiler option to statically link in libraries at link time
Link Intel provided libraries statically
Link Intel provided libraries dynamically
Tells the compiler to generate code for processors that support certain features.
Processors:
amberlake/broadwell/cannonlake/cascadelake/coffeelake/goldmont/goldmont-plus/haswell/icelake-client (or icelake)/icelake-server/ivybridge/kabylake/knl/knm/sandybridge/silvermont/skylake/skylake-avx512/tremont/whiskeylake
May generate instructions for processors that support the specified Intel® processor or microarchitecture code name.
Keywords knl and silvermont are only available on Linux* systems.
Keyword icelake is deprecated and may be removed in a future release.
core-avx2
Generates code for processors that support Intel® Advanced Vector Extensions 2 (Intel® AVX2), Intel® AVX, SSE4.2, SSE4.1, SSE3, SSE2, SSE, and SSSE3 instructions.
core-avx-i
Generates code for processors that support Float-16 conversion instructions and the RDRND instruction, Intel® Advanced Vector Extensions (Intel® AVX), Intel® SSE4.2, SSE4.1, SSE3, SSE2, SSE, and SSSE3 instructions.
corei7-avx
Generates code for processors that support Intel® Advanced Vector Extensions (Intel® AVX), Intel® SSE4.2, SSE4.1, SSE3, SSE2, SSE, and SSSE3 instructions.
corei7
Generates code for processors that support Intel® SSE4 Efficient Accelerated String and Text Processing instructions. May also generate code for Intel® SSE4 Vectorizing Compiler and Media Accelerator, Intel® SSE3, SSE2, SSE, and SSSE3 instructions.
atom
Generates code for processors that support MOVBE instructions, depending on the setting of option -minstruction (Linux* and macOS*) or /Qinstruction (Windows*). May also generate code for SSSE3 instructions and Intel® SSE3, SSE2, and SSE instructions.
core2
Generates code for the Intel® Core™2 processor family.
pentim4m
Generates for Intel® Pentium® 4 processors with MMX technology.
pentium-m/pentium4/pentium3/pentium
Generates code for Intel® Pentium® processors. Value pentium3 is only available on Linux* systems.
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Performs optimizations for specific processors but does not cause extended instruction sets to be used (unlike -march).
Processors:
generic
Optimizes code for the compiler's default behavior.
amberlake/broadwell/cannonlake/cascadelake/coffeelake/goldmont/goldmont-plus/haswell/icelake-client (or icelake)/icelake-server/ivybridge/kabylake/knl/knm/sandybridge/silvermont/skylake/skylake-avx512/tremont/whiskeylake
May generate instructions for processors that support the specified Intel® processor or microarchitecture code name.
Keywords knl and silvermont are only available on Linux* systems.
Keyword icelake is deprecated and may be removed in a future release.
core-avx2
Generates code for processors that support Intel® Advanced Vector Extensions 2 (Intel® AVX2), Intel® AVX, SSE4.2, SSE4.1, SSE3, SSE2, SSE, and SSSE3 instructions.
core-avx-i
Generates code for processors that support Float-16 conversion instructions and the RDRND instruction, Intel® Advanced Vector Extensions (Intel® AVX), Intel® SSE4.2, SSE4.1, SSE3, SSE2, SSE, and SSSE3 instructions.
corei7-avx
Generates code for processors that support Intel® Advanced Vector Extensions (Intel® AVX), Intel® SSE4.2, SSE4.1, SSE3, SSE2, SSE, and SSSE3 instructions.
corei7
Generates code for processors that support Intel® SSE4 Efficient Accelerated String and Text Processing instructions. May also generate code for Intel® SSE4 Vectorizing Compiler and Media Accelerator, Intel® SSE3, SSE2, SSE, and SSSE3 instructions.
atom
Generates code for processors that support MOVBE instructions, depending on the setting of option -minstruction (Linux* and macOS*) or /Qinstruction (Windows*). May also generate code for SSSE3 instructions and Intel® SSE3, SSE2, and SSE instructions.
core2
Generates code for the Intel® Core™2 processor family.
pentim4m
Generates for Intel® Pentium® 4 processors with MMX technology.
pentium-m/pentium4/pentium3/pentium
Generates code for Intel® Pentium® processors. Value pentium3 is only available on Linux* systems.
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Code is optimized for Intel(R) Core(TM)2 Duo processors, Intel(R) Core(TM)2 Quad
processors and Intel(R) Xeon(R) processors with SSSE3.
The resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
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Code is optimized for Intel Pentium M and compatible Intel processors. The
resulting code may contain unconditional use of features that are not supported
on other processors. This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced data layout and code
restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that
is not an Intel processor. If you use this option on a non-compatible processor
to compile the main program (in Fortran) or the function main() in C/C++, the
program will display a fatal run-time error if they are executed on unsupported
processors.
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Code is optimized for Intel Pentium 4 and compatible Intel processors;
this is the default for Intel?EM64T systems. The resulting code may contain
unconditional use of features that are not supported on other processors.
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Tells the auto-parallelizer to generate multithreaded code for loops that can be safely executed in parallel.
To use this option, you must also specify option O2 or O3. The default numbers of threads spawned is equal to
the number of processors detected in the system where the binary is compiled. Can be changed by setting the
environment variable OMP_NUM_THREADS
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The use of -Qparallel to generate auto-parallelized code requires spport libraries that are
dynamically linked by default. Specifying libguide.lib on the link line, statically links in
libguide.lib to allow auto-parallelized binaries to work on systems which do not have the dynamic version
of this library installed.
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The use of -Qparallel to generate auto-parallelized code requires spport libraries that are
dynamically linked by default. Specifying libguide40.lib on the link line, statically links in
libguide40.lib to allow auto-parallelized binaries to work on systems which do not have the
dynamic version of this library installed.
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Optimizes for Intel Pentium 4 and compatible processors with Streaming SIMD Extensions 2 (SSE2).
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(disable/enable[default] -[no-]prec-div)
-prec-div improves precision of floating-point divides. It has a slight
impact on speed. -no-prec-div disables this option and enables
optimizations that give slightly less precise results than full IEEE
division.
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(disable/enable[default] -[no-]prec-div)
-prec-sqrt improves precision of floating-point square root. It has a slight
impact on speed. -no-prec-sqrt disables this option and enables
optimizations that give slightly less precise results than full IEEE
division.
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Instrument program for profiling for the first phase of
two-phase profile guided otimization. This instrumentation gathers information
about a program's execution paths and data values but does not gather
information from hardware performance counters. The profile instrumentation
also gathers data for optimizations which are unique to profile-feedback
optimization.
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Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
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Enable SmartHeap and/or other library usage by forcing the linker to
ignore multiple definitions if present
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Enable SmartHeap library usage by forcing the linker to
ignore multiple definitions
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set the stack reserve amount specified to the linker
Enable/disable(DEFAULT) use of ANSI aliasing rules in
optimizations; user asserts that the program adheres to
these rules.
Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
Directs the compiler to inline calloc() calls as malloc()/memset()
Specify malloc configuration parameters. Specifying a non-zero value will
cause alternate configuration parameters to be set for how malloc allocates and frees
memory
Enable/disable(DEFAULT) calls to fast calloc function
Enables cache/bandwidth optimization for stores under conditionals (within vector loops)
Enable compiler to generate runtime control code for effective automatic parallelization
Select the method that the register allocator uses to partition each routine into regions
routine - one region per routine
block - one region per block
trace - one region per trace
loop - one region per loop
default - compiler selects best option
Select the method that the register allocator uses to partition each routine into regions
routine - one region per routine
block - one region per block
trace - one region per trace
loop - one region per loop
default - compiler selects best option
Enables more aggressive multi-versioning
Enable the compiler to generate multi-threaded code based on the OpenMP* directives
Enable the compiler to generate multi-threaded code based on the OpenMP* directives(New option.)
Make all local variables AUTOMATIC. Same as -automatic
Determines whether the compiler uses more aggressive unrolling for certain loops.
This option determines whether the compiler uses more aggressive unrolling for certain loops. The positive form of the option may improve performance.
This option enables aggressive, complete unrolling for loops with small constant trip counts.
Enables generation of streaming stores for optimization.
Specifies whether streaming stores are generated:
always - enables generation of streaming stores under the assumption that the application is memory bound
auto - compiler decides when streaming stores are used (DEFAULT)
never - disables generation of streaming stores
Determines whethre the compiler assumes that there are no "large" integers being used or being computed inside loops.
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Disables inline expansion of all intrinsic functions.
Disables conformance to the ANSI C and IEEE 754 standards for
floating-point arithmetic.
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Allows use of EBP as a general-purpose register in optimizations.
This option enables most speed optimizations, but disables some
that increase code size for a small speed benefit.
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This option enables global optimizations.
Specifies the level of inline function expansion.
Ob0 - Disables inlining of user-defined functions. Note that
statement functions are always inlined.
Ob1 - Enables inlining when an inline keyword or an inline
attribute is specified. Also enables inlining according
to the C++ language.
Ob2 - Enables inlining of any function at the compiler's
discretion.
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This option tells the compiler to separate functions into COMDATs
for the linker.
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This option enables read only string-pooling optimization.
This option enables read/write string-pooling optimization.
This option disables stack-checking for routines with 4096 bytes
of local variables and compiler temporaries.
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