Base Compiler Invocation
C benchmarks
-
- icl
![[user]](http://www.spec.org/auto/mpi2007/flags/user.png)
- CC, LD
-
Invoke the Intel C++ compiler
C++ benchmarks
126.lammps
-
- icl
- CXX, LD
-
Invoke the Intel C++ compiler
Fortran benchmarks
-
- ifort
- FC, LD
-
Invoke the Intel Fortran compiler
Invoke the Intel C++ compiler
Invoke the Intel C++ compiler
Invoke the Intel Fortran compiler
![[benchmark]](http://www.spec.org/auto/mpi2007/flags/benchmark.png)
SPEC_MPI_UC_NO_TRAILING_UNDERSCORE uppercases and removes trailing underscore
SPEC_MPI_WINDOWS_ICL may be used in SPEC MPI2007.
This macro indicates that Fortran functions called from C should have their names lower-cased.
Tell the compiler to append an underscore to external subroutine names
Tell the compiler to change routine names to all lowercase (same as /names:lowercase)
Tell the compiler to specify the level of compatibility to adhere to with Fortran PowerStation
Do not append an underscore to certain C functions which are designed to be invoked from Fortran. This setting should match the expected symbol mangling convention used by your Fortran compiler.
Tell the compiler to change routine names to all lowercase (same as /names:lowercase)
Portablity flag for successful compilation with Intel compiler on Microsoft Windows systems.
Tell the compiler to specify the level of compatibility to adhere to with Fortran PowerStation
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets. On IA-32
Windows platforms, -O3 sets the following:
/GF (/Qvc7 and above), /Gf (/Qvc6 and below), and /Ob2
This option improves precision of floating-point divides. It has a slight impact on speed.
With some optimizations, such as -xN and -xB (Linux) or /QxN and /QxB (Windows), 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 -no-prec-div (Linux and Mac OS) or /Qprec-div- (Windows), it enables optimizations that give slightly less precise results than full IEEE division.
Possible values are:
K Code is optimized for Intel Pentium III and compatible Intel processors.
W Code is optimized for Intel Pentium 4 and compatible Intel processors.
N Code is optimized for Intel Pentium 4 and compatible Intel processors with Streaming SIMD Extensions 2.
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.
B Code is optimized for Intel Pentium M and compatible Intel processors.
This option also enables new optimizations in addition to Intel processor-specific optimizations.
P Code is optimized for Intel Core Duo processors, Intel Core Solo processors,
Intel Pentium 4 processors with Streaming SIMD Extensions 3, and compatible Intel processors with
Streaming SIMD Extensions 3.
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.
T Code is optimized for Intel Core2 Duo processors, Intel Core2 Extreme processors, and the
Dual-Core Intel Xeon processor 5100 series.
This option also enables new optimizations in addition to Intel processor-specific optimizations
including advanced data layout and code restructuring optimizations to improve memory accesses
for Intel processors
Do not use these options if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
In particular, such programs compiled with processor values N, B, or P will display a fatal run-time error if they are executed on unsupported processors.
set the stack reserve amount specified to the linker
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets. On IA-32
Windows platforms, -O3 sets the following:
/GF (/Qvc7 and above), /Gf (/Qvc6 and below), and /Ob2
This option improves precision of floating-point divides. It has a slight impact on speed.
With some optimizations, such as -xN and -xB (Linux) or /QxN and /QxB (Windows), 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 -no-prec-div (Linux and Mac OS) or /Qprec-div- (Windows), it enables optimizations that give slightly less precise results than full IEEE division.
Possible values are:
K Code is optimized for Intel Pentium III and compatible Intel processors.
W Code is optimized for Intel Pentium 4 and compatible Intel processors.
N Code is optimized for Intel Pentium 4 and compatible Intel processors with Streaming SIMD Extensions 2.
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.
B Code is optimized for Intel Pentium M and compatible Intel processors.
This option also enables new optimizations in addition to Intel processor-specific optimizations.
P Code is optimized for Intel Core Duo processors, Intel Core Solo processors,
Intel Pentium 4 processors with Streaming SIMD Extensions 3, and compatible Intel processors with
Streaming SIMD Extensions 3.
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.
T Code is optimized for Intel Core2 Duo processors, Intel Core2 Extreme processors, and the
Dual-Core Intel Xeon processor 5100 series.
This option also enables new optimizations in addition to Intel processor-specific optimizations
including advanced data layout and code restructuring optimizations to improve memory accesses
for Intel processors
Do not use these options if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
In particular, such programs compiled with processor values N, B, or P will display a fatal run-time error if they are executed on unsupported processors.
set the stack reserve amount specified to the linker
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets. On IA-32
Windows platforms, -O3 sets the following:
/GF (/Qvc7 and above), /Gf (/Qvc6 and below), and /Ob2
This option improves precision of floating-point divides. It has a slight impact on speed.
With some optimizations, such as -xN and -xB (Linux) or /QxN and /QxB (Windows), 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 -no-prec-div (Linux and Mac OS) or /Qprec-div- (Windows), it enables optimizations that give slightly less precise results than full IEEE division.
Possible values are:
K Code is optimized for Intel Pentium III and compatible Intel processors.
W Code is optimized for Intel Pentium 4 and compatible Intel processors.
N Code is optimized for Intel Pentium 4 and compatible Intel processors with Streaming SIMD Extensions 2.
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.
B Code is optimized for Intel Pentium M and compatible Intel processors.
This option also enables new optimizations in addition to Intel processor-specific optimizations.
P Code is optimized for Intel Core Duo processors, Intel Core Solo processors,
Intel Pentium 4 processors with Streaming SIMD Extensions 3, and compatible Intel processors with
Streaming SIMD Extensions 3.
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.
T Code is optimized for Intel Core2 Duo processors, Intel Core2 Extreme processors, and the
Dual-Core Intel Xeon processor 5100 series.
This option also enables new optimizations in addition to Intel processor-specific optimizations
including advanced data layout and code restructuring optimizations to improve memory accesses
for Intel processors
Do not use these options if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
In particular, such programs compiled with processor values N, B, or P will display a fatal run-time error if they are executed on unsupported processors.
set the stack reserve amount specified to the linker
Enables O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop and memory
access transformations. Enables optimizations for maximum speed,
such as:
- Loop unrolling, including instruction scheduling
- Code replication to eliminate branches
- Padding the size of certain power-of-two arrays to allow
more efficient cache use.
On IA-32 and Intel EM64T processors, when O3 is used with options
-ax or -x (Linux) or with options /Qax or /Qx (Windows), the compiler
performs more aggressive data dependency analysis than for O2, which
may result in longer compilation times.
The O3 optimizations may not cause higher performance unless loop and
memory access transformations take place. The optimizations may slow
down code in some cases compared to O2 optimizations.
The O3 option is recommended for applications that have loops that heavily
use floating-point calculations and process large data sets. On IA-32
Windows platforms, -O3 sets the following:
/GF (/Qvc7 and above), /Gf (/Qvc6 and below), and /Ob2
This option improves precision of floating-point divides. It has a slight impact on speed.
With some optimizations, such as -xN and -xB (Linux) or /QxN and /QxB (Windows), 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 -no-prec-div (Linux and Mac OS) or /Qprec-div- (Windows), it enables optimizations that give slightly less precise results than full IEEE division.
Possible values are:
K Code is optimized for Intel Pentium III and compatible Intel processors.
W Code is optimized for Intel Pentium 4 and compatible Intel processors.
N Code is optimized for Intel Pentium 4 and compatible Intel processors with Streaming SIMD Extensions 2.
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.
B Code is optimized for Intel Pentium M and compatible Intel processors.
This option also enables new optimizations in addition to Intel processor-specific optimizations.
P Code is optimized for Intel Core Duo processors, Intel Core Solo processors,
Intel Pentium 4 processors with Streaming SIMD Extensions 3, and compatible Intel processors with
Streaming SIMD Extensions 3.
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.
T Code is optimized for Intel Core2 Duo processors, Intel Core2 Extreme processors, and the
Dual-Core Intel Xeon processor 5100 series.
This option also enables new optimizations in addition to Intel processor-specific optimizations
including advanced data layout and code restructuring optimizations to improve memory accesses
for Intel processors
Do not use these options if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
In particular, such programs compiled with processor values N, B, or P will display a fatal run-time error if they are executed on unsupported processors.
set the stack reserve amount specified to the linker
Tell the compiler to add directory to include file search path under compilation
Tell the compiler to add directory to include file search path under compilation
Tell the compiler to add directory to include file search path under compilation
Tell the compiler to add directory to include file search path under compilation
This section contains descriptions of flags that were included implicitly by other flags, but which do not have a permanent home at SPEC.
This option enables read only string-pooling optimization.
This option enables read/write string-pooling optimization.
Specifies the level of inline function expansion.
Ob0 - Disables inlining of user-defined functions. Note that statement functions are always inlined.
Ob1 - Enables inlining when an inline keyword or an inline attribute is specified. Also enables inlining according to the C++ language.
Ob2 - Enables inlining of any function at the compiler's discretion.
Enables optimizations for speed. This is the generally recommended
optimization level. This option also enables:
- Inlining of intrinsics
- Intra-file interprocedural optimizations, which include:
- inlining
- constant propagation
- forward substitution
- routine attribute propagation
- variable address-taken analysis
- dead static function elimination
- removal of unreferenced variables
- The following capabilities for performance gain:
- constant propagation
- copy propagation
- dead-code elimination
- global register allocation
- global instruction scheduling and control speculation
- loop unrolling
- optimized code selection
- partial redundancy elimination
- strength reduction/induction variable simplification
- variable renaming
- exception handling optimizations
- tail recursions
- peephole optimizations
- structure assignment lowering and optimizations
- dead store elimination
On IA-32 Windows platforms, -O2 sets the following:
/Og, /Oi-, /Os, /Oy, /Ob2, /GF (/Qvc7 and above), /Gf (/Qvc6 and below), /Gs, and /Gy.
Disables inline expansion of all intrinsic functions.
This option disables stack-checking for routines with 4096 bytes of local variables and compiler temporaries.
Allows use of EBP as a general-purpose register in optimizations.
This option tells the compiler to separate functions into COMDATs for the linker.
This option enables most speed optimizations, but disables some that increase code size for a small speed benefit.
This option enables global optimizations.
Enables optimizations for speed and disables some optimizations that
increase code size and affect speed.
To limit code size, this option:
- Enables global optimization; this includes data-flow analysis,
code motion, strength reduction and test replacement, split-lifetime
analysis, and instruction scheduling.
- Disables intrinsic recognition and intrinsics inlining.
The O1 option may improve performance for applications with very large
code size, many branches, and execution time not dominated by code within loops.
On IA-32 Windows platforms, -O1 sets the following:
/Qunroll0, /Oi-, /Op-, /Oy, /Gy, /Os, /GF (/Qvc7 and above), /Gf (/Qvc6 and below), /Ob2, and /Og
Tells the compiler the maximum number of times to unroll loops.
Disables conformance to the ANSI C and IEEE 754 standards for floating-point arithmetic.
Flag description origin markings:
|
Indicates that the flag description came from the user flags file. |
![[suite]](http://www.spec.org/auto/mpi2007/flags/suite.png) |
Indicates that the flag description came from the suite-wide flags file. |
|
Indicates that the flag description came from a per-benchmark flags file. |
For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact webmaster@spec.org
Copyright 2006-2010 Standard Performance Evaluation Corporation
Tested with SPEC MPI2007 v1.0.
Report generated on Tue Jul 22 13:33:03 2014 by SPEC MPI2007 flags formatter v1445.