CPU2006 Result Flag Description

Base Portability Flags

410.bwaves

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

416.gamess

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

433.milc

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

434.zeusmp

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

435.gromacs

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.
- -nofor_main
- LDPORTABILITY
- This option specifies that the main program is not written in Fortran. It is a link-time option that prevents the compiler from linking for_main.o into applications.
  
  For example, if the main program is written in C and calls a Fortran subprogram, specify -nofor-main when compiling the program with the ifort command. If you omit this option, the main program must be a Fortran program.

436.cactusADM

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.
- -nofor_main
- LDPORTABILITY
- This option specifies that the main program is not written in Fortran. It is a link-time option that prevents the compiler from linking for_main.o into applications.
  
  For example, if the main program is written in C and calls a Fortran subprogram, specify -nofor-main when compiling the program with the ifort command. If you omit this option, the main program must be a Fortran program.

437.leslie3d

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

444.namd

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

447.dealII

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

450.soplex

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

453.povray

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

454.calculix

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.
- -nofor_main
- LDPORTABILITY
- This option specifies that the main program is not written in Fortran. It is a link-time option that prevents the compiler from linking for_main.o into applications.
  
  For example, if the main program is written in C and calls a Fortran subprogram, specify -nofor-main when compiling the program with the ifort command. If you omit this option, the main program must be a Fortran program.

459.GemsFDTD

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

465.tonto

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

470.lbm

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

481.wrf

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.
- -DSPEC_CPU_CASE_FLAG
- CPORTABILITY
- This macro indicates that Fortran functions called from C should have their names lower-cased.
- -DSPEC_CPU_LINUX
- CPORTABILITY
- This macro indicates that the benchmark is being compiled on a Linux system.

482.sphinx3

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

Peak Portability Flags

410.bwaves

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

416.gamess

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

433.milc

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

434.zeusmp

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

435.gromacs

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.
- -nofor_main
- LDPORTABILITY
- This option specifies that the main program is not written in Fortran. It is a link-time option that prevents the compiler from linking for_main.o into applications.
  
  For example, if the main program is written in C and calls a Fortran subprogram, specify -nofor-main when compiling the program with the ifort command. If you omit this option, the main program must be a Fortran program.

436.cactusADM

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.
- -nofor_main
- LDPORTABILITY
- This option specifies that the main program is not written in Fortran. It is a link-time option that prevents the compiler from linking for_main.o into applications.
  
  For example, if the main program is written in C and calls a Fortran subprogram, specify -nofor-main when compiling the program with the ifort command. If you omit this option, the main program must be a Fortran program.

437.leslie3d

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

444.namd

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

447.dealII

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

450.soplex

- -D_FILE_OFFSET_BITS=64
- PORTABILITY
- This macro determines which file system interface will be used. Common file i/o calls like stat() and readdir() return off_t data that may or may not fit within a 32bit data structure if this flag is not used. With _FILE_OFFSET_BITS=64, types like off_t have a size of 64 bits. The truncation that happens without _FILE_OFFSET_BITS=64 has been observed to yield intermittent failures.
  
  Ex: RHEL7 distributions format partitions using xfs. Runtime errors are observed on such systems because sometimes returned values will not fit into 32bit data types that are a mismatch for xfs.
  
  See the gnuc feature test macros article for more information.

453.povray

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

454.calculix

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.
- -nofor_main
- LDPORTABILITY
- This option specifies that the main program is not written in Fortran. It is a link-time option that prevents the compiler from linking for_main.o into applications.
  
  For example, if the main program is written in C and calls a Fortran subprogram, specify -nofor-main when compiling the program with the ifort command. If you omit this option, the main program must be a Fortran program.

459.GemsFDTD

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

465.tonto

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

470.lbm

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

481.wrf

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.
- -DSPEC_CPU_CASE_FLAG
- CPORTABILITY
- This macro indicates that Fortran functions called from C should have their names lower-cased.
- -DSPEC_CPU_LINUX
- CPORTABILITY
- This macro indicates that the benchmark is being compiled on a Linux system.

482.sphinx3

- -DSPEC_CPU_LP64
- PORTABILITY
- 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.

Base Optimization Flags

C benchmarks

- -xCORE-AVX2
- OPTIMIZE
- 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.
- -ipo
- OPTIMIZE
- 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
- -O3
- OPTIMIZE
- 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.
- Includes:
  - -O2
    - -O1
      
      -funroll-loops
      
      -fno-builtin
      
      -mno-ieee-fp
      
      -fomit-framepointer
      
      -ffunction-sections
      
      -ftz
- -no-prec-div
- OPTIMIZE
- (disable/enable[default] -prec-div)
  -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.
- -qopt-prefetch
- OPTIMIZE
- Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
- -auto-p32
- COPTIMIZE
- This option instructs the compiler to analyze and transform the program so that 64-bit pointers are shrunk to 32-bit pointers wherever it is legal and safe to do so. In order for this option to be effective, the compiler must optimize using the -ipo option and must be able to analyze all library/external calls the program makes. This option has no effect unless you specify setting SSE3 or higher for option -x.
  
  This option requires that the application cannot exceed a 32-bit address space, otherwise unpredictable results can occur.
- -qopt-mem-layout-trans=3
- COPTIMIZE
- Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
  - 0: Disables memory layout transformations. This is the same as specifying -qno-opt-mem-layout-trans
  - 1: Enables basic memory layout transformations like structure splitting, structure peeling, field inlining, field reordering, array field transpose, increase field alignment etc.
  - 2: Enables more memory layout transformations like advanced structure splitting. This is the same as specifying -qopt-mem-layout-trans
  - 3: Compiler is more aggressive in using memory layout transformations. You should only use this setting if your system has more than 4GB of physical memory per core.

C++ benchmarks

- -xCORE-AVX2
- OPTIMIZE
- 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.
- -ipo
- OPTIMIZE
- 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
- -O3
- OPTIMIZE
- 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.
- Includes:
  - -O2
    - -O1
      
      -funroll-loops
      
      -fno-builtin
      
      -mno-ieee-fp
      
      -fomit-framepointer
      
      -ffunction-sections
      
      -ftz
- -no-prec-div
- OPTIMIZE
- (disable/enable[default] -prec-div)
  -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.
- -qopt-prefetch
- OPTIMIZE
- Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
- -auto-p32
- CXXOPTIMIZE
- This option instructs the compiler to analyze and transform the program so that 64-bit pointers are shrunk to 32-bit pointers wherever it is legal and safe to do so. In order for this option to be effective, the compiler must optimize using the -ipo option and must be able to analyze all library/external calls the program makes. This option has no effect unless you specify setting SSE3 or higher for option -x.
  
  This option requires that the application cannot exceed a 32-bit address space, otherwise unpredictable results can occur.
- -qopt-mem-layout-trans=3
- CXXOPTIMIZE
- Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
  - 0: Disables memory layout transformations. This is the same as specifying -qno-opt-mem-layout-trans
  - 1: Enables basic memory layout transformations like structure splitting, structure peeling, field inlining, field reordering, array field transpose, increase field alignment etc.
  - 2: Enables more memory layout transformations like advanced structure splitting. This is the same as specifying -qopt-mem-layout-trans
  - 3: Compiler is more aggressive in using memory layout transformations. You should only use this setting if your system has more than 4GB of physical memory per core.

Fortran benchmarks

- -xCORE-AVX2
- OPTIMIZE
- 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.
- -ipo
- OPTIMIZE
- 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
- -O3
- OPTIMIZE
- 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.
- Includes:
  - -O2
    - -O1
      
      -funroll-loops
      
      -fno-builtin
      
      -mno-ieee-fp
      
      -fomit-framepointer
      
      -ffunction-sections
      
      -ftz
- -no-prec-div
- OPTIMIZE
- (disable/enable[default] -prec-div)
  -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.
- -qopt-prefetch
- OPTIMIZE
- Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.

Benchmarks using both Fortran and C

- -xCORE-AVX2
- OPTIMIZE
- 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.
- -ipo
- OPTIMIZE
- 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
- -O3
- OPTIMIZE
- 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.
- Includes:
  - -O2
    - -O1
      
      -funroll-loops
      
      -fno-builtin
      
      -mno-ieee-fp
      
      -fomit-framepointer
      
      -ffunction-sections
      
      -ftz
- -no-prec-div
- OPTIMIZE
- (disable/enable[default] -prec-div)
  -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.
- -qopt-prefetch
- OPTIMIZE
- Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
- -auto-p32
- COPTIMIZE
- This option instructs the compiler to analyze and transform the program so that 64-bit pointers are shrunk to 32-bit pointers wherever it is legal and safe to do so. In order for this option to be effective, the compiler must optimize using the -ipo option and must be able to analyze all library/external calls the program makes. This option has no effect unless you specify setting SSE3 or higher for option -x.
  
  This option requires that the application cannot exceed a 32-bit address space, otherwise unpredictable results can occur.
- -qopt-mem-layout-trans=3
- COPTIMIZE
- Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
  - 0: Disables memory layout transformations. This is the same as specifying -qno-opt-mem-layout-trans
  - 1: Enables basic memory layout transformations like structure splitting, structure peeling, field inlining, field reordering, array field transpose, increase field alignment etc.
  - 2: Enables more memory layout transformations like advanced structure splitting. This is the same as specifying -qopt-mem-layout-trans
  - 3: Compiler is more aggressive in using memory layout transformations. You should only use this setting if your system has more than 4GB of physical memory per core.

Peak Optimization Flags

C benchmarks

C++ benchmarks

444.namd

- -prof-gen
- PASS1_CXXFLAGS, PASS1_LDFLAGS
- 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 guidaed optimization data with guards for threaded applications.
- -prof-use
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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
- -xCORE-AVX2
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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.
- -par-num-threads=1
- PASS1_CXXFLAGS, PASS1_LDFLAGS
- Allows for tuning of application performance by setting the number of threads to use in a parallel region. It has a similar effect as environment variable OMP_NUM_THREADS. This option overrides the environment variable when both are specified. Ex: -par-num-threads=1 specifies one thread to use.
- -ipo
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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
- -O3
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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.
- Includes:
  - -O2
    - -O1
      
      -funroll-loops
      
      -fno-builtin
      
      -mno-ieee-fp
      
      -fomit-framepointer
      
      -ffunction-sections
      
      -ftz
- -no-prec-div
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- (disable/enable[default] -prec-div)
  -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.
- -fno-alias
- CXXOPTIMIZE
- This options tells the compiler to assume no aliasing in the program.
- -auto-ilp32
- CXXOPTIMIZE
- This option instructs the compiler to analyze and transform the program so that 64-bit pointers are shrunk to 32-bit pointers, and 64-bit longs (on Linux) are shrunk into 32-bit longs wherever it is legal and safe to do so. In order for this option to be effective the compiler must be able to optimize using the -ipo/-Qipo option and must be able to analyze all library/external calls the program makes.
  
  This option requires that the size of the program executable never exceeds 2^32 bytes and all data values can be represented within 32 bits. If the program can run correctly in a 32-bit system, these requirements are implicitly satisfied. If the program violates these size restrictions, unpredictable behavior might occur.
- -qopt-mem-layout-trans=3
- CXXOPTIMIZE
- Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
  - 0: Disables memory layout transformations. This is the same as specifying -qno-opt-mem-layout-trans
  - 1: Enables basic memory layout transformations like structure splitting, structure peeling, field inlining, field reordering, array field transpose, increase field alignment etc.
  - 2: Enables more memory layout transformations like advanced structure splitting. This is the same as specifying -qopt-mem-layout-trans
  - 3: Compiler is more aggressive in using memory layout transformations. You should only use this setting if your system has more than 4GB of physical memory per core.

450.soplex

- -prof-gen
- PASS1_CXXFLAGS, PASS1_LDFLAGS
- 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 guidaed optimization data with guards for threaded applications.
- -prof-use
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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
- -xCORE-AVX2
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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.
- -par-num-threads=1
- PASS1_CXXFLAGS, PASS1_LDFLAGS
- Allows for tuning of application performance by setting the number of threads to use in a parallel region. It has a similar effect as environment variable OMP_NUM_THREADS. This option overrides the environment variable when both are specified. Ex: -par-num-threads=1 specifies one thread to use.
- -ipo
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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
- -O3
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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.
- Includes:
  - -O2
    - -O1
      
      -funroll-loops
      
      -fno-builtin
      
      -mno-ieee-fp
      
      -fomit-framepointer
      
      -ffunction-sections
      
      -ftz
- -no-prec-div
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- (disable/enable[default] -prec-div)
  -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.
- -qopt-malloc-options=3
- OPTIMIZE
- The compiler adds setup code in the C/C++/Fortran main function to enable optimal malloc algorithms:
  - n=0: Default, no changes to the malloc options. No call to mallopt() is made.
  - n=1: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x10000000. Call mallopt with the two settings.
  - n=2: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x40000000. Call mallopt with these two settings.
  - n=3: M_MMAP_MAX=0 and M_TRIM_THRESHOLD=-1. Call mallopt with these two settings. This will cause use of sbrk() calls instead of mmap() calls to get memory from the system.
  The two parameters, M_MMAP_MAX and M_TRIM_THRESHOLD, are described below
  
  Function: int mallopt (int param, int value) When calling mallopt, the param argument specifies the parameter to be set, and value the new value to be set. Possible choices for param, as defined in malloc.h, are:
  - M_TRIM_THRESHOLD This is the minimum size (in bytes) of the top-most, releasable chunk that will cause sbrk to be called with a negative argument in order to return memory to the system.
  - M_TOP_PAD This parameter determines the amount of extra memory to obtain from the system when a call to sbrk is required. It also specifies the number of bytes to retain when shrinking the heap by calling sbrk with a negative argument. This provides the necessary hysteresis in heap size such that excessive amounts of system calls can be avoided.
  - M_MMAP_THRESHOLD All chunks larger than this value are allocated outside the normal heap, using the mmap system call. This way it is guaranteed that the memory for these chunks can be returned to the system on free. Note that requests smaller than this threshold might still be allocated via mmap.
  - M_MMAP_MAX The maximum number of chunks to allocate with mmap. Setting this to zero disables all use of mmap.
- -qopt-mem-layout-trans=3
- CXXOPTIMIZE
- Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
  - 0: Disables memory layout transformations. This is the same as specifying -qno-opt-mem-layout-trans
  - 1: Enables basic memory layout transformations like structure splitting, structure peeling, field inlining, field reordering, array field transpose, increase field alignment etc.
  - 2: Enables more memory layout transformations like advanced structure splitting. This is the same as specifying -qopt-mem-layout-trans
  - 3: Compiler is more aggressive in using memory layout transformations. You should only use this setting if your system has more than 4GB of physical memory per core.

453.povray

- -prof-gen
- PASS1_CXXFLAGS, PASS1_LDFLAGS
- 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 guidaed optimization data with guards for threaded applications.
- -prof-use
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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
- -xCORE-AVX2
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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.
- -par-num-threads=1
- PASS1_CXXFLAGS, PASS1_LDFLAGS
- Allows for tuning of application performance by setting the number of threads to use in a parallel region. It has a similar effect as environment variable OMP_NUM_THREADS. This option overrides the environment variable when both are specified. Ex: -par-num-threads=1 specifies one thread to use.
- -ipo
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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
- -O3
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- 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.
- Includes:
  - -O2
    - -O1
      
      -funroll-loops
      
      -fno-builtin
      
      -mno-ieee-fp
      
      -fomit-framepointer
      
      -ffunction-sections
      
      -ftz
- -no-prec-div
- PASS2_CXXFLAGS, PASS2_LDFLAGS
- (disable/enable[default] -prec-div)
  -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.
- -unroll4
- CXXOPTIMIZE
- This option sets the maximum number of times a loop can be unrolled, to 4.
- -qopt-mem-layout-trans=3
- CXXOPTIMIZE
- Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
  - 0: Disables memory layout transformations. This is the same as specifying -qno-opt-mem-layout-trans
  - 1: Enables basic memory layout transformations like structure splitting, structure peeling, field inlining, field reordering, array field transpose, increase field alignment etc.
  - 2: Enables more memory layout transformations like advanced structure splitting. This is the same as specifying -qopt-mem-layout-trans
  - 3: Compiler is more aggressive in using memory layout transformations. You should only use this setting if your system has more than 4GB of physical memory per core.

Fortran benchmarks

410.bwaves

- -xCORE-AVX2
- OPTIMIZE
- 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.
- -ipo
- OPTIMIZE
- 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
- -O3
- OPTIMIZE
- 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.
- Includes:
  - -O2
    - -O1
      
      -funroll-loops
      
      -fno-builtin
      
      -mno-ieee-fp
      
      -fomit-framepointer
      
      -ffunction-sections
      
      -ftz
- -no-prec-div
- OPTIMIZE
- (disable/enable[default] -prec-div)
  -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.
- -qopt-prefetch
- OPTIMIZE
- Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.

416.gamess

- -prof-gen
- PASS1_FFLAGS, PASS1_LDFLAGS
- 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 guidaed optimization data with guards for threaded applications.
- -prof-use
- PASS2_FFLAGS, PASS2_LDFLAGS
- 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
- -xCORE-AVX2
- PASS2_FFLAGS, PASS2_LDFLAGS
- 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.
- -par-num-threads=1
- PASS1_FFLAGS, PASS1_LDFLAGS
- Allows for tuning of application performance by setting the number of threads to use in a parallel region. It has a similar effect as environment variable OMP_NUM_THREADS. This option overrides the environment variable when both are specified. Ex: -par-num-threads=1 specifies one thread to use.
- -ipo
- PASS2_FFLAGS, PASS2_LDFLAGS
- 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
- -O3
- PASS2_FFLAGS, PASS2_LDFLAGS
- 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.
- Includes:
  - -O2
    - -O1
      
      -funroll-loops
      
      -fno-builtin
      
      -mno-ieee-fp
      
      -fomit-framepointer
      
      -ffunction-sections
      
      -ftz
- -no-prec-div
- PASS2_FFLAGS, PASS2_LDFLAGS
- (disable/enable[default] -prec-div)
  -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.
- -unroll2
- OPTIMIZE
- This option sets the maximum number of times a loop can be unrolled, to 2.
- -inline-level=0
- OPTIMIZE
- Specifies the level of inline function expansion.
  
  0 - Disables inlining of user-defined functions. Note that statement functions are always inlined.
  
  1 - Enables inlining when an inline keyword or an inline attribute is specified. Also enables inlining according to the C++ language.
  
  2 - Enables inlining of any function at the compiler's discretion.
- -scalar-rep-
- OPTIMIZE
- -scalar-rep enables scalar replacement performed during loop transformation. To use this option, you must also specify O3. -scalar-rep- disables this optimization.

465.tonto

- -prof-gen
- PASS1_FFLAGS, PASS1_LDFLAGS
- 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 guidaed optimization data with guards for threaded applications.
- -prof-use
- PASS2_FFLAGS, PASS2_LDFLAGS
- 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
- -xCORE-AVX2
- PASS2_FFLAGS, PASS2_LDFLAGS
- 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.
- -par-num-threads=1
- PASS1_FFLAGS, PASS1_LDFLAGS
- Allows for tuning of application performance by setting the number of threads to use in a parallel region. It has a similar effect as environment variable OMP_NUM_THREADS. This option overrides the environment variable when both are specified. Ex: -par-num-threads=1 specifies one thread to use.
- -ipo
- PASS2_FFLAGS, PASS2_LDFLAGS
- 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
- -O3
- PASS2_FFLAGS, PASS2_LDFLAGS
- 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.
- Includes:
  - -O2
    - -O1
      
      -funroll-loops
      
      -fno-builtin
      
      -mno-ieee-fp
      
      -fomit-framepointer
      
      -ffunction-sections
      
      -ftz
- -no-prec-div
- PASS2_FFLAGS, PASS2_LDFLAGS
- (disable/enable[default] -prec-div)
  -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.
- -unroll4
- OPTIMIZE
- This option sets the maximum number of times a loop can be unrolled, to 4.
- -auto
- OPTIMIZE
- Make all local variables AUTOMATIC. Same as -automatic
- -inline-calloc
- OPTIMIZE
- Directs the compiler to inline calloc() calls as malloc()/memset()
- -qopt-malloc-options=3
- OPTIMIZE
- The compiler adds setup code in the C/C++/Fortran main function to enable optimal malloc algorithms:
  - n=0: Default, no changes to the malloc options. No call to mallopt() is made.
  - n=1: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x10000000. Call mallopt with the two settings.
  - n=2: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x40000000. Call mallopt with these two settings.
  - n=3: M_MMAP_MAX=0 and M_TRIM_THRESHOLD=-1. Call mallopt with these two settings. This will cause use of sbrk() calls instead of mmap() calls to get memory from the system.
  The two parameters, M_MMAP_MAX and M_TRIM_THRESHOLD, are described below
  
  Function: int mallopt (int param, int value) When calling mallopt, the param argument specifies the parameter to be set, and value the new value to be set. Possible choices for param, as defined in malloc.h, are:
  - M_TRIM_THRESHOLD This is the minimum size (in bytes) of the top-most, releasable chunk that will cause sbrk to be called with a negative argument in order to return memory to the system.
  - M_TOP_PAD This parameter determines the amount of extra memory to obtain from the system when a call to sbrk is required. It also specifies the number of bytes to retain when shrinking the heap by calling sbrk with a negative argument. This provides the necessary hysteresis in heap size such that excessive amounts of system calls can be avoided.
  - M_MMAP_THRESHOLD All chunks larger than this value are allocated outside the normal heap, using the mmap system call. This way it is guaranteed that the memory for these chunks can be returned to the system on free. Note that requests smaller than this threshold might still be allocated via mmap.
  - M_MMAP_MAX The maximum number of chunks to allocate with mmap. Setting this to zero disables all use of mmap.

Benchmarks using both Fortran and C

435.gromacs

- -prof-gen
- PASS1_CFLAGS, PASS1_FFLAGS, PASS1_LDFLAGS
- 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 guidaed optimization data with guards for threaded applications.
- -prof-use
- PASS2_CFLAGS, PASS2_FFLAGS, PASS2_LDFLAGS
- 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
- -xCORE-AVX2
- PASS2_CFLAGS, PASS2_FFLAGS, PASS2_LDFLAGS
- 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.
- -par-num-threads=1
- PASS1_CFLAGS, PASS1_FFLAGS, PASS1_LDFLAGS
- Allows for tuning of application performance by setting the number of threads to use in a parallel region. It has a similar effect as environment variable OMP_NUM_THREADS. This option overrides the environment variable when both are specified. Ex: -par-num-threads=1 specifies one thread to use.
- -qopt-prefetch
- OPTIMIZE
- Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.
- -auto-ilp32
- COPTIMIZE
- This option instructs the compiler to analyze and transform the program so that 64-bit pointers are shrunk to 32-bit pointers, and 64-bit longs (on Linux) are shrunk into 32-bit longs wherever it is legal and safe to do so. In order for this option to be effective the compiler must be able to optimize using the -ipo/-Qipo option and must be able to analyze all library/external calls the program makes.
  
  This option requires that the size of the program executable never exceeds 2^32 bytes and all data values can be represented within 32 bits. If the program can run correctly in a 32-bit system, these requirements are implicitly satisfied. If the program violates these size restrictions, unpredictable behavior might occur.
- -qopt-mem-layout-trans=3
- COPTIMIZE
- Controls the level of memory layout transformations performed by the compiler. This option can improve cache reuse and cache locality.
  - 0: Disables memory layout transformations. This is the same as specifying -qno-opt-mem-layout-trans
  - 1: Enables basic memory layout transformations like structure splitting, structure peeling, field inlining, field reordering, array field transpose, increase field alignment etc.
  - 2: Enables more memory layout transformations like advanced structure splitting. This is the same as specifying -qopt-mem-layout-trans
  - 3: Compiler is more aggressive in using memory layout transformations. You should only use this setting if your system has more than 4GB of physical memory per core.

481.wrf

- basepeak = yes

Implicitly Included Flags

This section contains descriptions of flags that were included implicitly by other flags, but which do not have a permanent home at SPEC.

Commands and Options Used to Submit Benchmark Runs

Shell, Environment, and Other Software Settings

Red Hat Specific features

Operating System Tuning Parameters

Firmware / BIOS / Microcode Settings

For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact webmaster@spec.org
Copyright 2006-2017 Standard Performance Evaluation Corporation
Tested with SPEC CPU2006 v1.2.
Report generated on Tue Jul 25 15:51:21 2017 by SPEC CPU2006 flags formatter v6906.

	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.

CPU2006 Flag DescriptionHuawei Huawei 1288H V5 (Intel Xeon Platinum 8160)

Base Compiler Invocation

Peak Compiler Invocation

Base Portability Flags

Peak Portability Flags

Base Optimization Flags

Peak Optimization Flags

Implicitly Included Flags

Red Hat Specific features

CPU2006 Flag Description
Huawei Huawei 1288H V5 (Intel Xeon Platinum 8160)