CPU2006 Flag Description
Fujitsu Siemens Computers CELSIUS M460, Intel Core 2 Duo E6850 processor
Compilers: Intel(R) C++ Compiler and Intel(R) Visual Fortran Compiler
for applications running on Intel(R) 64, Version 10.1
Operating system: Windows Vista Ultimate, x64 Version
Last updated: 11-Dec-2007
The text for many of the descriptions below was taken
from the documentation of the Intel Compilers.
This documentation is copyright © 2007 Intel Corporation. All Rights Reserved.
The original documentation is distributed with the Intel compilers.
Base Portability Flags
-
- -DSPEC_CPU_P64
![[suite]](http://www.spec.org/auto/cpu2006/flags/suite.png)
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
Peak Portability Flags
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
-
-
- -DSPEC_CPU_P64
- PORTABILITY
-
This option is used to indicate that the host system's integers and longs,
are 32-bits wide, and pointers are 64-bits wide. Not all benchmarks
recognize this macro, but the preferred practice for data model selection
applies the flags to all benchmarks; this flag description is a placeholder
for those benchmarks that do not recognize this macro.
Base Optimization Flags
-
- -fast
![[user]](http://www.spec.org/auto/cpu2006/flags/user.png)
- COPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
- -Qparallel
- COPTIMIZE
-
This option 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 -O2 or -O3.
-
- -F1000000000
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- libguide40.lib
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
- -fast
- CXXOPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
- -Qparallel
- CXXOPTIMIZE
-
This option 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 -O2 or -O3.
-
- -Qcxx-features
- CXXOPTIMIZE
-
This option enables standard C++ features without disabling Microsoft
features within the bounds of what is provided in the Microsoft headers and
libraries.
This option has the same effect as specifying -GX -GR.
-GX Enables C++ exception handling.
-GR Enables C++ Run Time Type Information (RTTI).
-
- -F1000000000
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- libguide40.lib
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
-
-
- -fast
- FOPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
- -Qparallel
- FOPTIMIZE
-
This option 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 -O2 or -O3.
-
- -F1000000000
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- libguide40.lib
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
- -fast
- COPTIMIZE, FOPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
- -Qparallel
- COPTIMIZE, FOPTIMIZE
-
This option 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 -O2 or -O3.
-
- -F1000000000
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- libguide40.lib
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
Peak Optimization Flags
-
- -Qprof_gen
- PASS1_CFLAGS, PASS1_LDFLAGS
-
This option instruments a program for profiling
as first step in Profile Guided Optimization.
Profile Guided Optimization (PGO) consists of 3 phases:
Phase 1: Compile and generate instrumented code in preparation
to gather profiling information (compiler flag -Qprof_gen).
Phase 2: Execute the instrumented code and gather profiling information.
Phase 3: Recompile the code and use the profiling information
for improved optimization (compiler flag -Qprof_use).
The option -Qprof_gen instruments a program
for profiling to get the execution count of each basic block.
It also creates a new static profile information file (.spi).
This flag is used in phase 1 of the Profile Guided Optimizer (PGO)
to instruct the compiler to produce code in your object files
in preparation for instrumented execution.
The instrumented code
- Gathers information regarding execution paths.
- Gathers information regarding data values.
- Does not use hardware performance counters.
-
- -Qprof_use
- PASS2_CFLAGS, PASS2_LDFLAGS
-
This option enables the use of profiling information during optimization
as final step in Profile Guided Optimization.
Profile Guided Optimization (PGO) consists of 3 phases:
Phase 1: Compile and generate instrumented code in preparation
to gather profiling information (compiler flag -Qprof_gen).
Phase 2: Execute the instrumented code and gather profiling information.
Phase 3: Recompile the code and use the profiling information
for improved optimization (compiler flag -Qprof_use).
The option -Qprof_use instructs the compiler to use the profiling
information from phase 2 of PGO in order to produce a profile-optimized
executable (phase 3 of PGO).
It also enables function splitting (option -Qfnsplit)
and function grouping during optimization.
Note that there is no way to turn off function grouping
if you enable it using this option.
The recompilation with -Qprof_use
- Uses information regarding execution paths.
- Uses information regarding data values.
- Does not use hardware performance counters.
- Uses techniques (like function grouping) which are not available without PGO.
- Includes:
-
- -fast
- COPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
- -fast
- COPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
-
-
- -Qprefetch
- COPTIMIZE
-
This option enables prefetch insertion optimization.
The goal of prefetching is to reduce cache misses
by providing hints to the processor about when data
should be loaded into the cache.
Default is -Qprefetch- which disables this kind of optimization.
-
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
- -fast
- COPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
-
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
- -fast
- CXXOPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
- -Qcxx-features
- CXXOPTIMIZE
-
This option enables standard C++ features without disabling Microsoft
features within the bounds of what is provided in the Microsoft headers and
libraries.
This option has the same effect as specifying -GX -GR.
-GX Enables C++ exception handling.
-GR Enables C++ Run Time Type Information (RTTI).
-
-
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
-
-
- -Qprof_gen
- PASS1_CXXFLAGS, PASS1_LDFLAGS
-
This option instruments a program for profiling
as first step in Profile Guided Optimization.
Profile Guided Optimization (PGO) consists of 3 phases:
Phase 1: Compile and generate instrumented code in preparation
to gather profiling information (compiler flag -Qprof_gen).
Phase 2: Execute the instrumented code and gather profiling information.
Phase 3: Recompile the code and use the profiling information
for improved optimization (compiler flag -Qprof_use).
The option -Qprof_gen instruments a program
for profiling to get the execution count of each basic block.
It also creates a new static profile information file (.spi).
This flag is used in phase 1 of the Profile Guided Optimizer (PGO)
to instruct the compiler to produce code in your object files
in preparation for instrumented execution.
The instrumented code
- Gathers information regarding execution paths.
- Gathers information regarding data values.
- Does not use hardware performance counters.
-
- -Qprof_use
- PASS2_CXXFLAGS, PASS2_LDFLAGS
-
This option enables the use of profiling information during optimization
as final step in Profile Guided Optimization.
Profile Guided Optimization (PGO) consists of 3 phases:
Phase 1: Compile and generate instrumented code in preparation
to gather profiling information (compiler flag -Qprof_gen).
Phase 2: Execute the instrumented code and gather profiling information.
Phase 3: Recompile the code and use the profiling information
for improved optimization (compiler flag -Qprof_use).
The option -Qprof_use instructs the compiler to use the profiling
information from phase 2 of PGO in order to produce a profile-optimized
executable (phase 3 of PGO).
It also enables function splitting (option -Qfnsplit)
and function grouping during optimization.
Note that there is no way to turn off function grouping
if you enable it using this option.
The recompilation with -Qprof_use
- Uses information regarding execution paths.
- Uses information regarding data values.
- Does not use hardware performance counters.
- Uses techniques (like function grouping) which are not available without PGO.
- Includes:
-
- -fast
- CXXOPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
- -Qcxx-features
- CXXOPTIMIZE
-
This option enables standard C++ features without disabling Microsoft
features within the bounds of what is provided in the Microsoft headers and
libraries.
This option has the same effect as specifying -GX -GR.
-GX Enables C++ exception handling.
-GR Enables C++ Run Time Type Information (RTTI).
-
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
-
-
- -O2
- FOPTIMIZE
-
Optimizes for speed.
The -O2 option includes the following options:
- -Og
- -Oi-
- -Os
- -Oy
- -Ob2
- -GF
- -Gs
- -Gy
- -Qftz
This options defaults to ON.
This option also enables:
- inlining of intrinsics
- Intra-file interprocedural optimizations including:
- inlining
- constant propagation
- forward substitution
- routine attribute propagation
- variable address-taken analysis
- dead static function elimination
- removal of unreferenced variables.
- The following performance optimizations:
- copy propogation.
- dead-code elimination
- global register allocation
- global instruction scheduling and control speculation
- loop unrolliing
- optimized code selection
- partial redundancy elimination
- strength reduction/induction variable simplification
- variable renaming
- exception handling optimizations
- tail recursions
- peephole optimizations
- structure assignment lowering and optimization
- dead store elimination
- Includes:
-
-
- -QxT
- FOPTIMIZE
-
-Qxprocessor This option directs the compiler
to generate specialized and optimized code for the Intel processor
that executes your program.
It lets you target your program to run on a specific Intel processor.
processor Is the processor
for which you want to target your program.
Here: T Code is optimized
generating SSSE3, SSE3, SSE2, and SSE instructions for Intel processors.
Code can be optimized for the Intel Core 2 Duo processor family.
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.
Programs compiled with -QxT will display a fatal run-time error
if they are executed on unsupported processors.
-
-
- -Qprec-div-
- FOPTIMIZE
-
-Qprec-div improves precision of floating-point divides.
It has a slight impact on speed.
-Qprec-div- disables this option.
With some optimizations, -QxN and -QxB,
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,
use this option to disable the floating-point
division-to-multiplication optimization.
The result is more accurate, with some loss of performance.
If you specify -Qprec-div-, it enables optimizations
that give slightly less precise results than full IEEE division.
Default is -Qprec-div
-
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
- -fast
- FOPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
-
- -Qauto
- FOPTIMIZE
-
This option places local variables, except those declared as SAVE, to the run-time stack.
It is as if the variables were declared with the AUTOMATIC attribute.
It does not affect variables that have the SAVE attribute or ALLOCATABLE attribute,
or variables that appear in an EQUIVALENCE statement or in a common block.
This option may provide a performance gain for your program, but if your program depends on
variables having the same value as the last time the routine was invoked, your program may not
function properly.
If you want to cause variables to be placed in static memory, specify /Qsave (Windows).
-
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
- -Qprof_gen
- PASS1_CFLAGS, PASS1_FFLAGS, PASS1_LDFLAGS
-
This option instruments a program for profiling
as first step in Profile Guided Optimization.
Profile Guided Optimization (PGO) consists of 3 phases:
Phase 1: Compile and generate instrumented code in preparation
to gather profiling information (compiler flag -Qprof_gen).
Phase 2: Execute the instrumented code and gather profiling information.
Phase 3: Recompile the code and use the profiling information
for improved optimization (compiler flag -Qprof_use).
The option -Qprof_gen instruments a program
for profiling to get the execution count of each basic block.
It also creates a new static profile information file (.spi).
This flag is used in phase 1 of the Profile Guided Optimizer (PGO)
to instruct the compiler to produce code in your object files
in preparation for instrumented execution.
The instrumented code
- Gathers information regarding execution paths.
- Gathers information regarding data values.
- Does not use hardware performance counters.
-
- -Qprof_use
- PASS2_CFLAGS, PASS2_FFLAGS, PASS2_LDFLAGS
-
This option enables the use of profiling information during optimization
as final step in Profile Guided Optimization.
Profile Guided Optimization (PGO) consists of 3 phases:
Phase 1: Compile and generate instrumented code in preparation
to gather profiling information (compiler flag -Qprof_gen).
Phase 2: Execute the instrumented code and gather profiling information.
Phase 3: Recompile the code and use the profiling information
for improved optimization (compiler flag -Qprof_use).
The option -Qprof_use instructs the compiler to use the profiling
information from phase 2 of PGO in order to produce a profile-optimized
executable (phase 3 of PGO).
It also enables function splitting (option -Qfnsplit)
and function grouping during optimization.
Note that there is no way to turn off function grouping
if you enable it using this option.
The recompilation with -Qprof_use
- Uses information regarding execution paths.
- Uses information regarding data values.
- Does not use hardware performance counters.
- Uses techniques (like function grouping) which are not available without PGO.
- Includes:
-
- -fast
- OPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
- -Qprof_gen
- PASS1_CFLAGS, PASS1_FFLAGS, PASS1_LDFLAGS
-
This option instruments a program for profiling
as first step in Profile Guided Optimization.
Profile Guided Optimization (PGO) consists of 3 phases:
Phase 1: Compile and generate instrumented code in preparation
to gather profiling information (compiler flag -Qprof_gen).
Phase 2: Execute the instrumented code and gather profiling information.
Phase 3: Recompile the code and use the profiling information
for improved optimization (compiler flag -Qprof_use).
The option -Qprof_gen instruments a program
for profiling to get the execution count of each basic block.
It also creates a new static profile information file (.spi).
This flag is used in phase 1 of the Profile Guided Optimizer (PGO)
to instruct the compiler to produce code in your object files
in preparation for instrumented execution.
The instrumented code
- Gathers information regarding execution paths.
- Gathers information regarding data values.
- Does not use hardware performance counters.
-
- -Qprof_use
- PASS2_CFLAGS, PASS2_FFLAGS, PASS2_LDFLAGS
-
This option enables the use of profiling information during optimization
as final step in Profile Guided Optimization.
Profile Guided Optimization (PGO) consists of 3 phases:
Phase 1: Compile and generate instrumented code in preparation
to gather profiling information (compiler flag -Qprof_gen).
Phase 2: Execute the instrumented code and gather profiling information.
Phase 3: Recompile the code and use the profiling information
for improved optimization (compiler flag -Qprof_use).
The option -Qprof_use instructs the compiler to use the profiling
information from phase 2 of PGO in order to produce a profile-optimized
executable (phase 3 of PGO).
It also enables function splitting (option -Qfnsplit)
and function grouping during optimization.
Note that there is no way to turn off function grouping
if you enable it using this option.
The recompilation with -Qprof_use
- Uses information regarding execution paths.
- Uses information regarding data values.
- Does not use hardware performance counters.
- Uses techniques (like function grouping) which are not available without PGO.
- Includes:
-
- -fast
- OPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
- -Qparallel
- OPTIMIZE
-
This option 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 -O2 or -O3.
-
- -Qprefetch
- OPTIMIZE
-
This option enables prefetch insertion optimization.
The goal of prefetching is to reduce cache misses
by providing hints to the processor about when data
should be loaded into the cache.
Default is -Qprefetch- which disables this kind of optimization.
-
-
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
-
- -Qprof_gen
- PASS1_CFLAGS, PASS1_FFLAGS, PASS1_LDFLAGS
-
This option instruments a program for profiling
as first step in Profile Guided Optimization.
Profile Guided Optimization (PGO) consists of 3 phases:
Phase 1: Compile and generate instrumented code in preparation
to gather profiling information (compiler flag -Qprof_gen).
Phase 2: Execute the instrumented code and gather profiling information.
Phase 3: Recompile the code and use the profiling information
for improved optimization (compiler flag -Qprof_use).
The option -Qprof_gen instruments a program
for profiling to get the execution count of each basic block.
It also creates a new static profile information file (.spi).
This flag is used in phase 1 of the Profile Guided Optimizer (PGO)
to instruct the compiler to produce code in your object files
in preparation for instrumented execution.
The instrumented code
- Gathers information regarding execution paths.
- Gathers information regarding data values.
- Does not use hardware performance counters.
-
- -Qprof_use
- PASS2_CFLAGS, PASS2_FFLAGS, PASS2_LDFLAGS
-
This option enables the use of profiling information during optimization
as final step in Profile Guided Optimization.
Profile Guided Optimization (PGO) consists of 3 phases:
Phase 1: Compile and generate instrumented code in preparation
to gather profiling information (compiler flag -Qprof_gen).
Phase 2: Execute the instrumented code and gather profiling information.
Phase 3: Recompile the code and use the profiling information
for improved optimization (compiler flag -Qprof_use).
The option -Qprof_use instructs the compiler to use the profiling
information from phase 2 of PGO in order to produce a profile-optimized
executable (phase 3 of PGO).
It also enables function splitting (option -Qfnsplit)
and function grouping during optimization.
Note that there is no way to turn off function grouping
if you enable it using this option.
The recompilation with -Qprof_use
- Uses information regarding execution paths.
- Uses information regarding data values.
- Does not use hardware performance counters.
- Uses techniques (like function grouping) which are not available without PGO.
- Includes:
-
- -fast
- OPTIMIZE
-
Maximizes speed across the entire program.
In Windows, it sets the following options:
-O3 -Qipo -Qprec-div- -QxT
Note that programs compiled with the -QxT option
will detect non-compatible processors and generate
an error message during execution.
The -QxT option that is set by the -fast option
cannot be overridden by other command line options.
If you specify -fast and a differnt processor-specific option,
such as -QxN, the compiler will issue a warning that explains
the -QxT option cannot be overridden.
- Includes:
-
-
- EXTRA_LDFLAGS
-
Specifies the stack reserve amount for the program.
-F<n>
<n> is the stack reserve amount.
It can be specified as a decimal integer or by using a C-style convention
for constants (for example, -F0x1000).
Default: The stack size default is chosen by the operating system.
-
- EXTRA_LIBS
-
The use of -Qparallel to generate auto-parallelized code
requires support 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.
Implicitly Included Flags
This section contains descriptions of flags that were included implicitly
by other flags, but which do not have a permanent home at SPEC.
-
- -O3
-
Optimizes for speed. Enables high-level optimization. This level does
not guarantee higher performance. Using this option may increase the
compilation time. Impact on performance is application dependent, some
applications may not see a performance improvement.
The optimizations include:
- All optimizations done with -O2
- 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.
- When used with -Qax or -Qx, it causes the compiler to perform
more aggressive data dependency analysis than for -O2.
- Includes:
-
- -O2
-
Optimizes for speed.
The -O2 option includes the following options:
- -Og
- -Oi-
- -Os
- -Oy
- -Ob2
- -GF
- -Gs
- -Gy
- -Qftz
This options defaults to ON.
This option also enables:
- inlining of intrinsics
- Intra-file interprocedural optimizations including:
- inlining
- constant propagation
- forward substitution
- routine attribute propagation
- variable address-taken analysis
- dead static function elimination
- removal of unreferenced variables.
- The following performance optimizations:
- copy propogation.
- dead-code elimination
- global register allocation
- global instruction scheduling and control speculation
- loop unrolliing
- optimized code selection
- partial redundancy elimination
- strength reduction/induction variable simplification
- variable renaming
- exception handling optimizations
- tail recursions
- peephole optimizations
- structure assignment lowering and optimization
- dead store elimination
- Includes:
-
-
-
-
- -Oy
-
Enables [disables] the use of the EBP register in optimizations.
When you disable with -Oy-, the EBP register is used as frame pointer.
-Oy has the effect of reducing the number of general-purpose registers by 1,
and can produce slightly less efficient code.
Default enabled
-
- -Ob<n>
-
n = 0
Disables inlining of user-defined functions.
However, statement functions are always inlined
n = 1
Enables inlining of functions declared with the __inline keyword.
Also enables inlining according to the C++ language
n = 2
Enables inlining of any function.
However, the compiler decides which functions are inlined.
This option enables interprocedural optimizations and has the same
effect as specifying option Qip.
Default enabled with n = 2
-
-
-
-
- -Qftz
-
This option flushes denormal results to zero when the application
is in the gradual underflow mode. It may improve performance
if the denormal values are not critical to your application's behavior.
This option only has an effect when the main program is being compiled.
It sets the ftz mode for the process.
-
- -Qprec-div-
-
-Qprec-div improves precision of floating-point divides.
It has a slight impact on speed.
-Qprec-div- disables this option.
With some optimizations, -QxN and -QxB,
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,
use this option to disable the floating-point
division-to-multiplication optimization.
The result is more accurate, with some loss of performance.
If you specify -Qprec-div-, it enables optimizations
that give slightly less precise results than full IEEE division.
Default is -Qprec-div
-
- -QxT
-
-Qxprocessor This option directs the compiler
to generate specialized and optimized code for the Intel processor
that executes your program.
It lets you target your program to run on a specific Intel processor.
processor Is the processor
for which you want to target your program.
Here: T Code is optimized
generating SSSE3, SSE3, SSE2, and SSE instructions for Intel processors.
Code can be optimized for the Intel Core 2 Duo processor family.
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.
Programs compiled with -QxT will display a fatal run-time error
if they are executed on unsupported processors.
-
- -Qipo
-
-Qipo[n]
This option enables interprocedural optimizations between files.
This is also called multifile interprocedural optimization (multifile IPO)
or Whole Program Optimization (WPO).
When you specify this option, the compiler performs inline function expansion
for calls to functions defined in separate files.
You cannot specify the names for the object files that are created.
n Is an optional integer that specifies
the number of object files the compiler should create.
The integer must be greater than or equal to 0.
If you do not specify n, the default is 0.
If n is 0, the compiler decides whether to create one or more object files
based on an estimate of the size of the application.
It generates one object file for small applications,
and two or more object files for large applications.
If n is greater than 0, the compiler generates n object files,
unless n exceeds the number of source files (m),
in which case the compiler generates only m object files.
-
- -Qfnsplit
-
Enables function splitting.
This option enables function splitting if -Qprof-use is also specified.
Otherwise, this option has no effect.
It is enabled automatically if you specify -Qprof-use. If you do not specify
one of those options, the default is -Qfnsplit-, which disables
function splitting but leaves function grouping enabled.
To disable function splitting when you use -Qprof-use, specify -Qfnsplit-.
Platform settings
One or more of the following settings may have been set.
If so, the corresponding notes sections of the report will say so;
and you can read below to find out more about what these settings mean.
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 Windows system with 8 cores:
set OMP_NUM_THREADS=8
Default is the number of cores visible to the OS.
KMP_AFFINITY
KMP_AFFINITY = , 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,2.
Thread 0 will mapped to core 2, thread 1 will be mapped to core 3, and
so on in a round-robin fashion.
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.
Snoop Filter Enabled/Disabled:
The Snoop Filter is designed to reduce system bus utilization
coming from cache misses. On the Intel 5000X and 5400 chipset,
it is built as a cache structure able to minimize unnecessary
snoop traffic.
When enabled, it can lead to significant memory performance
improvements for several workstation applications
on suitable memory configurations.
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 15:16:00 2014 by SPEC CPU2006 flags formatter v6906.
![[benchmark]](http://www.spec.org/auto/cpu2006/flags/benchmark.png)