Copyright © 2006 Intel Corporation. All Rights Reserved.
![[user]](http://www.spec.org/auto/cpu2006/flags/user.png)
Invoke the Intel C/C++ compiler for IA32 applications in VS 2005 compatibility mode
Invoke the Intel C++ compiler in C99 mode
Invoke the Intel C/C++ compiler for IA32 applications in VS 2005 compatibility mode
Invoke the Intel C/C++ compiler for IA32 applications in VS 2005 compatibility mode
Invoke the Intel C++ compiler in C99 mode
Invoke the Intel C/C++ compiler for IA32 applications in VS 2005 compatibility mode
![[benchmark]](http://www.spec.org/auto/cpu2006/flags/benchmark.png)
SPEC_CPU_WIN32 sets up types for gcc's compile time arithmetic, reflects the lack of a unistd.g file, sets the size and existence of the __int64 type, and sets the default page size on Windows.
This flag can be used as a portability flag on systems which do not have the standard header file "stdint.h". Inclusion of this flag defines the value of INT64_MIN (if it is not defined) and sets the "int64" type (if it is not set already)
This flag is set when building 464.h264ref on Windows systems.
-Qoption,string,options This option passes options to a specified tool.
string Is the name of the tool.
Here: cpp indicates the C++ preprocessor.
options Are one or more comma-separated,
valid options for the designated tool.
Here: --no_wchar_t_keyword is passed to C++ preprocessor to provide
the information that there is no wchar_t keyword.
This flag must be used with Microsoft Visual Studio 2005.
It avoids syntax errors coming from the use of wchar_t in 483.xalancbmk.
SPEC_CPU_WIN32 sets up types for gcc's compile time arithmetic, reflects the lack of a unistd.g file, sets the size and existence of the __int64 type, and sets the default page size on Windows.
This flag can be used as a portability flag on systems which do not have the standard header file "stdint.h". Inclusion of this flag defines the value of INT64_MIN (if it is not defined) and sets the "int64" type (if it is not set already)
This flag is set when building 464.h264ref on Windows systems.
-Qoption,string,options This option passes options to a specified tool.
string Is the name of the tool.
Here: cpp indicates the C++ preprocessor.
options Are one or more comma-separated,
valid options for the designated tool.
Here: --no_wchar_t_keyword is passed to C++ preprocessor to provide
the information that there is no wchar_t keyword.
This flag must be used with Microsoft Visual Studio 2005.
It avoids syntax errors coming from the use of wchar_t in 483.xalancbmk.
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
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
Enable compiler to generate runtime control code for effective automatic parallelization. This option generates code to perform run-time checks for loops that have symbolic loop bounds. If the granularity of a loop is greater than the parallelization threshold, the loop will be executed in parallel. If you do not specify this option, the compiler may not parallelize loops with symbolic loop bounds if the compile-time granularity estimation of a loop can not ensure it is beneficial to parallelize the loop.
Enables cache/bandwidth optimization for stores under conditionals (within vector loops) This option tells the compiler to perform a conditional check in a vectorized loop. This checking avoids unnecessary stores and may improve performance by conserving bandwidth.
set the stack reserve amount specified to the linker
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
Enable C++ Exception Handling and RTTI
This option has the same effect as specifying /GX /GR.
set the stack reserve amount specified to the linker
MicroQuill SmartHeap Library available from http://www.microquill.com/
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
Enable SmartHeap library usage by forcing the linker to ignore multiple definitions
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.
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
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
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.
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
Enable compiler to generate runtime control code for effective automatic parallelization. This option generates code to perform run-time checks for loops that have symbolic loop bounds. If the granularity of a loop is greater than the parallelization threshold, the loop will be executed in parallel. If you do not specify this option, the compiler may not parallelize loops with symbolic loop bounds if the compile-time granularity estimation of a loop can not ensure it is beneficial to parallelize the loop.
set the stack reserve amount specified to the linker
MicroQuill SmartHeap Library available from http://www.microquill.com/
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
Enable SmartHeap library usage by forcing the linker to ignore multiple definitions
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.
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
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
set the stack reserve amount specified to the linker
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
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.
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
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
set the stack reserve amount specified to the linker
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
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.
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
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.
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.
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
-Qprec-div- enables optimizations that give slightly less precise results than full IEEE division.
When you specify -Qprec-div- along with some optimizations, such as /QxT, the compiler may change floating-point division computations into multiplication by the reciprocal of the denominator. For example, A/B is computed as A * (1/B) to improve the speed of the computation.
However, sometimes the value produced by this transformation is not as accurate as full IEEE division. When it is important to have fully precise IEEE division, do not use -Qprec-div- which will enable the default -Qprec-div and the result is more accurate, with some loss of performance.
Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
set the stack reserve amount specified to the linker
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.
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
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
Tells the compiler the maximum number of times to unroll loops. A value of 0 disables loop unrolling.
Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
Multi-versioning is used for generating different versions of the loop based on run time dependence testing, alignment and checking for short/long trip counts. If this option is turned on, it will trigger more versioning at the expense of creating more overhead to check for pointer aliasing and scalar replacement.
set the stack reserve amount specified to the linker
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
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.
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
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
Tells the compiler the maximum number of times to unroll loops. A value of 0 disables loop unrolling.
set the stack reserve amount specified to the linker
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
Tells the compiler the maximum number of times to unroll loops. A value of 0 disables loop unrolling.
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.
Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
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
Enable compiler to generate runtime control code for effective automatic parallelization. This option generates code to perform run-time checks for loops that have symbolic loop bounds. If the granularity of a loop is greater than the parallelization threshold, the loop will be executed in parallel. If you do not specify this option, the compiler may not parallelize loops with symbolic loop bounds if the compile-time granularity estimation of a loop can not ensure it is beneficial to parallelize the loop.
set the stack reserve amount specified to the linker
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
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.
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
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
Tells the compiler the maximum number of times to unroll loops. A value of 0 disables loop unrolling.
Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
set the stack reserve amount specified to the linker
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
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.
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
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
Select the method that the register allocator uses to partition each routine into regions
Enable C++ Exception Handling and RTTI
This option has the same effect as specifying /GX /GR.
set the stack reserve amount specified to the linker
MicroQuill SmartHeap Library available from http://www.microquill.com/
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
Enable SmartHeap library usage by forcing the linker to ignore multiple definitions
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.
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
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
Select the method that the register allocator uses to partition each routine into regions
Enable C++ Exception Handling and RTTI
This option has the same effect as specifying /GX /GR.
set the stack reserve amount specified to the linker
MicroQuill SmartHeap Library available from http://www.microquill.com/
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
Enable SmartHeap library usage by forcing the linker to ignore multiple definitions
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.
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
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)
-Qipo (enables interprocedural optimizations across files)
-QxT (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)
-Qprec-div- (disable -prec-div) where -Qprec-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.
Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
Enable C++ Exception Handling and RTTI
This option has the same effect as specifying /GX /GR.
set the stack reserve amount specified to the linker
MicroQuill SmartHeap Library available from http://www.microquill.com/
The use of -Qparallel to generate auto-parallelized code requires supporting 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.
Enable SmartHeap library usage by forcing the linker to ignore multiple definitions
This allows alloca to be set to the compiler's preferred alloca by SPEC rules.
This allows alloca to be set to the compiler's preferred alloca by SPEC rules.
This section contains descriptions of flags that were included implicitly by other flags, but which do not have a permanent home at SPEC.
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
This option enables read only string-pooling optimization.
This option enables read/write string-pooling optimization.
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.
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.
Disables inline expansion of all intrinsic functions.
This option disables stack-checking for routines with 4096 bytes of local variables and compiler temporaries.
Allows use of EBP as a general-purpose register in optimizations.
This option tells the compiler to separate functions into COMDATs for the linker.
This option enables most speed optimizations, but disables some that increase code size for a small speed benefit.
This option enables global optimizations.
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
Tells the compiler the maximum number of times to unroll loops. A value of 0 disables loop unrolling.
Disables conformance to the ANSI C and IEEE 754 standards for floating-point arithmetic.
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
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.
-Qprec-div- enables optimizations that give slightly less precise results than full IEEE division.
When you specify -Qprec-div- along with some optimizations, such as /QxT, the compiler may change floating-point division computations into multiplication by the reciprocal of the denominator. For example, A/B is computed as A * (1/B) to improve the speed of the computation.
However, sometimes the value produced by this transformation is not as accurate as full IEEE division. When it is important to have fully precise IEEE division, do not use -Qprec-div- which will enable the default -Qprec-div and the result is more accurate, with some loss of performance.
This option enables C++ exception handling.
Enables C++ Run Time Type Information (RTTI).
Platform settings
One or more of the following settings may have been set. If so, the "General Notes" section of the report will say so; and you can read below to find out more about what these settings mean.
KMP_STACKSIZE
Specify stack size to be allocated for each thread.
KMP_AFFINITY
KMP_AFFINITY = < physical | logical >, starting-core-id
specifies the static mapping of user threads to physical cores. For example,
if you have a system configured with 8 cores, OMP_NUM_THREADS=8 and
KMP_AFFINITY=physical,0 then thread 0 will mapped to core 0, thread 1 will be mapped to core 1, and
so on in a round-robin fashion.
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 (Linux and Mac OS X) or /Qopenmp and /Qparallel (Windows). Example syntax on a Linux system with 8 cores: export OMP_NUM_THREADS=8
Hardware Prefetch:
This BIOS option allows the enabling/disabling of a processor mechanism to prefetch data into the cache according to a pattern-recognition algorithm.
In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking to verify improved performance in their environment.
Adjacent Sector Prefetch:
This BIOS option allows the enabling/disabling of a processor mechanism to fetch the adjacent cache line within an 128-byte sector that contains the data needed due to a cache line miss.
In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking to verify improved performance in their environment.
submit= specperl -e "system sprintf qq{start /b /wait /affinity %x %s}, (1<<$SPECUSERNUM), qq{ $command } "
When running multiple copies of benchmarks, the SPEC config file feature submit is sometimes used to cause individual jobs to be bound to specific processors. This specific submit command is used for Linux. The description of the elements of the command are:
Flag description origin markings:
|
Indicates that the flag description came from the user flags file. |
![[suite]](http://www.spec.org/auto/cpu2006/flags/suite.png) |
Indicates that the flag description came from the suite-wide flags file. |
|
Indicates that the flag description came from a per-benchmark flags file. |
For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact webmaster@spec.org
Copyright 2006-2014 Standard Performance Evaluation Corporation
Tested with SPEC CPU2006 v1.0.
Report generated on Tue Jul 22 15:29:18 2014 by SPEC CPU2006 flags formatter v6906.