Compilers: Intel(R) C++ Compiler and Intel(R) Visual Fortran Compiler
for applications running on IA-32 and
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.
![[user]](http://www.spec.org/auto/cpu2006/flags/user.png)
Invoke Intel C/C++ compiler for applications
running on IA-32.
Also used to invoke linker for C/C++ programs.
Specifies compatibilty with Microsoft Visual Studio 2005.
This option enables/disables C99 support for C programs.
Invoke Intel C/C++ compiler for applications
running on IA-32.
Also used to invoke linker for C/C++ programs.
Specifies compatibilty with Microsoft Visual Studio 2005.
This option enables/disables C99 support for C programs.
Invoke the
Intel C/C++ compiler for applications running on Intel 64.
Also used to invoke linker for C/C++ programs.
Set the path of the header files to be used by the Intel C/C++ compiler for applications running on Intel 64.
Set the path of the library files to be used with object files fom the Intel C/C++ compiler for applications running on Intel 64.
Set the path of libraries of Microsoft Visual Studio 2005.
Needed to link object files from the
Intel C/C++ compiler for applications running on Intel 64.
Set additional path of libraries of Microsoft Visual Studio 2005.
Needed to link object files from the
Intel C/C++ compiler for applications running on Intel 64.
Invoke the
Intel C/C++ compiler for applications running on Intel 64.
Also used to invoke linker for C/C++ programs.
Set the path of the header files to be used by the Intel C/C++ compiler for applications running on Intel 64.
Set the path of the library files to be used with object files fom the Intel C/C++ compiler for applications running on Intel 64.
Set the path of libraries of Microsoft Visual Studio 2005.
Needed to link object files from the
Intel C/C++ compiler for applications running on Intel 64.
Set additional path of libraries of Microsoft Visual Studio 2005.
Needed to link object files from the
Intel C/C++ compiler for applications running on Intel 64.
![[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.
![[suite]](http://www.spec.org/auto/cpu2006/flags/suite.png)
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.
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 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.
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.
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.
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.
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.
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.
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).
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.
Link with MicroQuill SmartHeap Library.
Available from
http://www.microquill.com/
Force Linking even if multiple entry names are found.
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
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
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.
Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
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.
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.
Link with MicroQuill SmartHeap Library.
Available from
http://www.microquill.com/
Force Linking even if multiple entry names are found.
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
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
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.
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.
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.
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
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
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.
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.
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
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
-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.
Optimizes for speed.
The -O2 option includes the following options:
This options defaults to ON.
This option also enables:
-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.
-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
Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
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.
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
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
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.
-Qunrolln tells the compiler the maximum number
of times to unroll loops.
If n is not specified, the optimizer determines
how many times loops can be unrolled.
If n is 0, loop unrolling is disabled.
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.
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.
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
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
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.
-Qunrolln tells the compiler the maximum number
of times to unroll loops.
If n is not specified, the optimizer determines
how many times loops can be unrolled.
If n is 0, loop unrolling is disabled.
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.
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
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
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.
-Qunrolln tells the compiler the maximum number
of times to unroll loops.
If n is not specified, the optimizer determines
how many times loops can be unrolled.
If n is 0, loop unrolling is disabled.
Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
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.
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
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
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.
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
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).
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.
Link with MicroQuill SmartHeap Library.
Available from
http://www.microquill.com/
Force Linking even if multiple entry names are found.
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
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
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.
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
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).
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.
Link with MicroQuill SmartHeap Library.
Available from
http://www.microquill.com/
Force Linking even if multiple entry names are found.
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
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
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.
Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.
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).
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.
Link with MicroQuill SmartHeap Library.
Available from
http://www.microquill.com/
Force Linking even if multiple entry names are found.
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.
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:
Optimizes for speed.
The -O2 option includes the following options:
This options defaults to ON.
This option also enables:
Enables global optimizations.
Enables/disables inline expansion of intrinsic functions.
Default enabled
This option enables most speed optimizations, but disables some that increase code size for a small speed benefit.
Default enabled
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
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
This option enables read-only string-pooling optimization.
Disables stack-checking for routines with n or more bytes of local variables and compiler temporaries.
Default enabled with n = 4096.
Packages functions to enable linker optimization.
Default enabled
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 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
-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[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.
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-.
Flag description origin markings:
|
Indicates that the flag description came from the user flags file. |
|
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 17:57:48 2014 by SPEC CPU2006 flags formatter v6906.