Base Compiler Invocation
C benchmarks
-
- icc
![[user]](https://www.spec.org/auto/cpu2017/images/user.png)
- CC, LD
-
Invoke the Intel C compiler.
Fortran benchmarks
-
- ifort
- FC, LD
-
Invoke the Intel Fortran compiler.
Copyright © 2016 Intel Corporation. All Rights Reserved.
Invoke the Intel C compiler.
Invoke the Intel Fortran compiler.
Invoke the Intel C compiler.
Invoke the Intel oneAPI DPC++ C compiler.
Invoke the Intel Fortran compiler.
![[suite]](https://www.spec.org/auto/cpu2017/images/suite.png)
This option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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.
![[benchmark]](https://www.spec.org/auto/cpu2017/images/benchmark.png)
This macro indicates that Fortran functions called from C should have their names lower-cased.
Specifies that the format will be big endian for INTEGER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and big endian IEEE floating-point for REAL*4, REAL*8, REAL*16, COMPLEX*8, COMPLEX*16, or COMPLEX*32.
This option is used to indicate that the host system's integers are 32-bits wide, and longs 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.
Fortran to C symbol naming. C symbol names are lower case with one underscore. _symbol
This option is used to indicate that the host system's integers are 32-bits wide, and longs 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.
For netcdf, if defined uses Fortran symbol names ABC as abc_
Specifies that the format will be big endian for INTEGER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and big endian IEEE floating-point for REAL*4, REAL*8, REAL*16, COMPLEX*8, COMPLEX*16, or COMPLEX*32.
Specifies that the units for the OPEN statement RECL specifier (record length) value are in bytes for unformatted data files, not longwords (four-byte units). For formatted files, the RECL value is always in bytes.
This option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 macro indicates that Fortran functions called from C should have their names lower-cased.
Specifies that the format will be big endian for INTEGER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and big endian IEEE floating-point for REAL*4, REAL*8, REAL*16, COMPLEX*8, COMPLEX*16, or COMPLEX*32.
This option is used to indicate that the host system's integers are 32-bits wide, and longs 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.
Fortran to C symbol naming. C symbol names are lower case with one underscore. _symbol
This option is used to indicate that the host system's integers are 32-bits wide, and longs 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.
For netcdf, if defined uses Fortran symbol names ABC as abc_
Specifies that the format will be big endian for INTEGER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and big endian IEEE floating-point for REAL*4, REAL*8, REAL*16, COMPLEX*8, COMPLEX*16, or COMPLEX*32.
Specifies that the units for the OPEN statement RECL specifier (record length) value are in bytes for unformatted data files, not longwords (four-byte units). For formatted files, the RECL value is always in bytes.
This option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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 option is used to indicate that the host system's integers are 32-bits wide, and longs 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.
Compiles for a 64-bit (LP64) data model.
Sets the language dialect to conform to the indicated C standard.
Code is optimized for Intel(R) processors with support for AVX2 instructions. The resulting code may contain unconditional use of features that are not supported on other processors. This option also enables new optimizations in addition to Intel processor-specific optimizations including advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
Multi-file ip optimizations that includes:
- inline function expansion
- interprocedural constant propogation
- dead code elimination
- propagation of function characteristics
- passing arguments in registers
- loop-invariant code motion
Enable O2 optimizations plus more aggressive optimizations, such as prefetching, scalar replacement, and loop and memory access transformations. Enable optimizations for maximum speed, such as:
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.
-no-prec-div enables optimizations that give slightly less precise results than full IEEE division.
When you specify -no-prec-div along 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, do not use -no-prec-div. This will enable the default -prec-div and the result will be more accurate, with some loss of performance.
Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
Allow optimizations for floating point arithmetic that assume arguments and results are not NaNs or Infinities
Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
This option instructs compiler to align branches and fused branches on 32 byte boundaries
Compiles for a 64-bit (LP64) data model.
Enable SmartHeap and/or other library usage by forcing the linker to ignore multiple definitions if present
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
Code is optimized for Intel(R) processors with support for AVX2 instructions. The resulting code may contain unconditional use of features that are not supported on other processors. This option also enables new optimizations in addition to Intel processor-specific optimizations including advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
Multi-file ip optimizations that includes:
- inline function expansion
- interprocedural constant propogation
- dead code elimination
- propagation of function characteristics
- passing arguments in registers
- loop-invariant code motion
Enable O2 optimizations plus more aggressive optimizations, such as prefetching, scalar replacement, and loop and memory access transformations. Enable optimizations for maximum speed, such as:
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.
-no-prec-div enables optimizations that give slightly less precise results than full IEEE division.
When you specify -no-prec-div along 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, do not use -no-prec-div. This will enable the default -prec-div and the result will be more accurate, with some loss of performance.
Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
Allow optimizations for floating point arithmetic that assume arguments and results are not NaNs or Infinities
Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
This option instructs compiler to align branches and fused branches on 32 byte boundaries
Specify build time link path for jemalloc 64bit built to support the CPU 2017 build. See jemalloc.net for more information.
Linker toggle to specify jemalloc linker library. See jemalloc.net for more information.
Compiles for a 64-bit (LP64) data model.
Sets the language dialect to conform to the indicated C standard.
Enable SmartHeap and/or other library usage by forcing the linker to ignore multiple definitions if present
Code is optimized for Intel(R) processors with support for AVX2 instructions. The resulting code may contain unconditional use of features that are not supported on other processors. This option also enables new optimizations in addition to Intel processor-specific optimizations including advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
Multi-file ip optimizations that includes:
- inline function expansion
- interprocedural constant propogation
- dead code elimination
- propagation of function characteristics
- passing arguments in registers
- loop-invariant code motion
Enable O2 optimizations plus more aggressive optimizations, such as prefetching, scalar replacement, and loop and memory access transformations. Enable optimizations for maximum speed, such as:
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.
-no-prec-div enables optimizations that give slightly less precise results than full IEEE division.
When you specify -no-prec-div along 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, do not use -no-prec-div. This will enable the default -prec-div and the result will be more accurate, with some loss of performance.
Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
Allow optimizations for floating point arithmetic that assume arguments and results are not NaNs or Infinities
Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
This option instructs compiler to align branches and fused branches on 32 byte boundaries
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
Specify build time link path for jemalloc 64bit built to support the CPU 2017 build. See jemalloc.net for more information.
Linker toggle to specify jemalloc linker library. See jemalloc.net for more information.
Compiles for a 64-bit (LP64) data model.
Sets the language dialect to conform to the indicated C standard.
Enable SmartHeap and/or other library usage by forcing the linker to ignore multiple definitions if present
Code is optimized for Intel(R) processors with support for AVX2 instructions. The resulting code may contain unconditional use of features that are not supported on other processors. This option also enables new optimizations in addition to Intel processor-specific optimizations including advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
Multi-file ip optimizations that includes:
- inline function expansion
- interprocedural constant propogation
- dead code elimination
- propagation of function characteristics
- passing arguments in registers
- loop-invariant code motion
Enable O2 optimizations plus more aggressive optimizations, such as prefetching, scalar replacement, and loop and memory access transformations. Enable optimizations for maximum speed, such as:
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.
-no-prec-div enables optimizations that give slightly less precise results than full IEEE division.
When you specify -no-prec-div along 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, do not use -no-prec-div. This will enable the default -prec-div and the result will be more accurate, with some loss of performance.
Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
Allow optimizations for floating point arithmetic that assume arguments and results are not NaNs or Infinities
Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
This option instructs compiler to align branches and fused branches on 32 byte boundaries
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
Specify build time link path for jemalloc 64bit built to support the CPU 2017 build. See jemalloc.net for more information.
Linker toggle to specify jemalloc linker library. See jemalloc.net for more information.
Compiles for a 64-bit (LP64) data model.
Enable SmartHeap and/or other library usage by forcing the linker to ignore multiple definitions if present
Code is optimized for Intel(R) processors with support for AVX2 instructions. The resulting code may contain unconditional use of features that are not supported on other processors. This option also enables new optimizations in addition to Intel processor-specific optimizations including advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
Enable O3 optimizations plus more aggressive optimizations, such as -ffinite-math-only –no-prec-div
Enable fast math mode. This option may yield faster code for programs that do not require the guarantees of exact implementation of IEEE or ISO rules/specifications for math functions.
Performs link time optimizations, which is also known as Interprocedural Optimizations.
Generate floating-point arithmetic for selected unit unit. Here use scalar floating-point instructions present in the SSE instruction set
Tells the compiler the maximum number of times to unroll loops. For example -funroll-loops0 would disable unrolling of loops.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
This option instructs compiler to define the relative error, measured by the number of correct bits,for math library function results
This option instructs compiler to align branches and fused branches on 32 byte boundaries
Specify build time link path for jemalloc 64bit built to support the CPU 2017 build. See jemalloc.net for more information.
Linker toggle to specify jemalloc linker library. See jemalloc.net for more information.
Compiles for a 64-bit (LP64) data model.
Enable SmartHeap and/or other library usage by forcing the linker to ignore multiple definitions if present
Instrument program for profiling for the first phase of two-phase profile guided otimization. This instrumentation gathers information about a program's execution paths and data values but does not gather information from hardware performance counters. The profile instrumentation also gathers data for optimizations which are unique to profile-feedback optimization.
-profgen:threadsafe option collects profile guided optimization data with guards for threaded applications.
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
Definition of this macro indicates that compilation for parallel operation is disabled, and that any OpenMP directives or pragmas will not be visible to the compiler. This macro overrides the behavior of -DSPEC_OPENMP when they both appear in the list of compilation flags.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
Multi-file ip optimizations that includes:
- inline function expansion
- interprocedural constant propogation
- dead code elimination
- propagation of function characteristics
- passing arguments in registers
- loop-invariant code motion
Code is optimized for Intel(R) processors with support for AVX2 instructions. The resulting code may contain unconditional use of features that are not supported on other processors. This option also enables new optimizations in addition to Intel processor-specific optimizations including advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
Enable O2 optimizations plus more aggressive optimizations, such as prefetching, scalar replacement, and loop and memory access transformations. Enable optimizations for maximum speed, such as:
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.
-no-prec-div enables optimizations that give slightly less precise results than full IEEE division.
When you specify -no-prec-div along 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, do not use -no-prec-div. This will enable the default -prec-div and the result will be more accurate, with some loss of performance.
Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
Allow optimizations for floating point arithmetic that assume arguments and results are not NaNs or Infinities
Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
This option instructs compiler to align branches and fused branches on 32 byte boundaries
Specify build time link path for jemalloc 64bit built to support the CPU 2017 build. See jemalloc.net for more information.
Linker toggle to specify jemalloc linker library. See jemalloc.net for more information.
Compiles for a 64-bit (LP64) data model.
Sets the language dialect to conform to the indicated C standard.
Enable SmartHeap and/or other library usage by forcing the linker to ignore multiple definitions if present
Instrument program for profiling for the first phase of two-phase profile guided otimization. This instrumentation gathers information about a program's execution paths and data values but does not gather information from hardware performance counters. The profile instrumentation also gathers data for optimizations which are unique to profile-feedback optimization.
-profgen:threadsafe option collects profile guided optimization data with guards for threaded applications.
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -prof-use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file.
Without any other options, the current directory is
searched for .dyn files
Multi-file ip optimizations that includes:
- inline function expansion
- interprocedural constant propogation
- dead code elimination
- propagation of function characteristics
- passing arguments in registers
- loop-invariant code motion
Code is optimized for Intel(R) processors with support for AVX2 instructions. The resulting code may contain unconditional use of features that are not supported on other processors. This option also enables new optimizations in addition to Intel processor-specific optimizations including advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors.
Do not use this option if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.
Enable O2 optimizations plus more aggressive optimizations, such as prefetching, scalar replacement, and loop and memory access transformations. Enable optimizations for maximum speed, such as:
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.
-no-prec-div enables optimizations that give slightly less precise results than full IEEE division.
When you specify -no-prec-div along 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, do not use -no-prec-div. This will enable the default -prec-div and the result will be more accurate, with some loss of performance.
Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
Allow optimizations for floating point arithmetic that assume arguments and results are not NaNs or Infinities
Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
Definition of this macro indicates that compilation for parallel operation is disabled, and that any OpenMP directives or pragmas will not be visible to the compiler. This macro overrides the behavior of -DSPEC_OPENMP when they both appear in the list of compilation flags.
Definition of this macro indicates that compilation for parallel operation is enabled, and that any OpenMP directives or pragmas will be visible to the compiler. The behavior of this macro is overridden if -DSPEC_SUPPRESS_OPENMP also appears in the list of compilation flags.
This option instructs compiler to align branches and fused branches on 32 byte boundaries
Option standard-realloc-lhs (the default), tells the compiler that when the left-hand side of an assignment is an allocatable object, it should be reallocated to the shape of the right-hand side of the assignment before the assignment occurs. This is the current Fortran Standard definition. This feature may cause extra overhead at run time. This option has the same effect as option assume realloc_lhs.
If you specify nostandard-realloc-lhs, the compiler uses the old Fortran 2003 rules when interpreting assignment statements. The left-hand side is assumed to be allocated with the correct shape to hold the right-hand side. If it is not, incorrect behavior will occur. This option has the same effect as option assume norealloc_lhs.
Specify build time link path for jemalloc 64bit built to support the CPU 2017 build. See jemalloc.net for more information.
Linker toggle to specify jemalloc linker library. See jemalloc.net for more information.
This section contains descriptions of flags that were included implicitly by other flags, but which do not have a permanent home at SPEC.
Enable 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
Enable optimizations for speed and disables some optimizations that increase code size and affect speed.
To limit code size, this option:
The O1 option may improve performance for applications with very large code size, many branches, and execution time not dominated by code within loops.
-O1 sets the following options:Tells the compiler the maximum number of times to unroll loops. For example -funroll-loops0 would disable unrolling of loops.
-fno-builtin disables inline expansion for all intrinsic functions.
This option trades off floating-point precision for speed by removing the restriction to conform to the IEEE standard.
EBP is used as a general-purpose register in optimizations.
Places each function in its own COMDAT section.
Flushes denormal results to zero.
Enable O2 optimizations plus more aggressive optimizations, such as prefetching, scalar replacement, and loop and memory access transformations. Enable optimizations for maximum speed, such as:
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.
Governors are power schemes for the CPU. It is in-kernel pre-configured power schemes for the CPU and allows you to change the clock speed of the CPUs on the fly. On Linux systems can set the govenor for all CPUs through the cpupower utility with the following command:
Below are govenors in the Linux kernel.
A commandline interface for switching between different tuning profiles available in supported Linux distributions. The distribution provided profiles are located in /usr/lib/tuned and the user defined profiles in /etc/tuned. To set a profile, one can issue the command "tuned-adm profile (profile_name)". Below are details about some relevant profiles.
Flag description origin markings:
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Indicates that the flag description came from the user flags file. |
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Indicates that the flag description came from the suite-wide flags file. |
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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 info@spec.org
Copyright 2017-2021 Standard Performance Evaluation Corporation
Tested with SPEC CPU2017 v1.1.8.
Report generated on 2021-09-30 13:56:04 by SPEC CPU2017 flags formatter v5178.