CPU2017 Flag Description
H3C H3C R4900 G2 (Intel Xeon E5-2620 v4, 2.10 GHz)

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.

• • -ansi-alias
  • 
  • OPTIMIZE

  • Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.

• • -qopt-mem-layout-trans=3
  • 
  • OPTIMIZE

  • 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 -no-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 -opt-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.
• • -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.

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.

• • -ansi-alias
  • 
  • OPTIMIZE

  • Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.

• • -qopt-mem-layout-trans=3
  • 
  • OPTIMIZE

  • 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 -no-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 -opt-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.
• • -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.

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.

• • -ansi-alias
  • 
  • OPTIMIZE

  • Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.

• • -qopt-mem-layout-trans=3
  • 
  • OPTIMIZE

  • 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 -no-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 -opt-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.
• • -heap-arrays
  • 
  • FOPTIMIZE

  • Puts automatic arrays and arrays created for temporary computations on the heap instead of the stack.

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.

• • -ansi-alias
  • 
  • OPTIMIZE

  • Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.

• • -qopt-mem-layout-trans=3
  • 
  • OPTIMIZE

  • 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 -no-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 -opt-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.
• • -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.

• • -heap-arrays
  • 
  • FOPTIMIZE

  • Puts automatic arrays and arrays created for temporary computations on the heap instead of the stack.

Benchmarks using both C 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.

• • -ansi-alias
  • 
  • OPTIMIZE

  • Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.

• • -qopt-mem-layout-trans=3
  • 
  • OPTIMIZE

  • 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 -no-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 -opt-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.
• • -auto-p32
  • 
  • COPTIMIZE, 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.

Benchmarks using Fortran, C, 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.

• • -ansi-alias
  • 
  • OPTIMIZE

  • Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.

• • -qopt-mem-layout-trans=3
  • 
  • OPTIMIZE

  • 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 -no-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 -opt-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.
• • -auto-p32
  • 
  • COPTIMIZE, 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.

• • -heap-arrays
  • 
  • FOPTIMIZE

  • Puts automatic arrays and arrays created for temporary computations on the heap instead of the stack.

Peak Optimization Flags

C benchmarks

519.lbm_r

• • basepeak = yes

538.imagick_r

• • -xCORE-AVX2
  • 
  • PASS2_CFLAGS, PASS2_LDCFLAGS

  • 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.

• • -prof-genthreadsafe
  • 
  • PASS1_CFLAGS, PASS1_LDCFLAGS

  • Produces an instrumented object file that includes the collection of PGO data on applications that use a high level of parallelism.

• • -ipo
  • 
  • PASS2_CFLAGS, PASS2_LDCFLAGS

  • 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_CFLAGS, PASS2_LDCFLAGS

  • 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
• • -par-num-threads=1
  • 
  • PASS1_CFLAGS, PASS1_LDCFLAGS

  • 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.

• • -no-prec-div
  • 
  • PASS2_CFLAGS, PASS2_LDCFLAGS
  • (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.

• • -prof-use
  • 
  • PASS2_CFLAGS, PASS2_LDCFLAGS

  • 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

• • -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.

• • -ansi-alias
  • 
  • COPTIMIZE

  • Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.

544.nab_r

• • Same as 538.imagick_r

C++ benchmarks

• • -xCORE-AVX2
  • 
  • PASS2_CXXFLAGS, PASS2_LDCXXFLAGS

  • 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.

• • -prof-genthreadsafe
  • 
  • PASS1_CXXFLAGS, PASS1_LDCXXFLAGS

  • Produces an instrumented object file that includes the collection of PGO data on applications that use a high level of parallelism.

• • -ipo
  • 
  • PASS2_CXXFLAGS, PASS2_LDCXXFLAGS

  • 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_LDCXXFLAGS

  • 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
• • -par-num-threads=1
  • 
  • PASS1_CXXFLAGS, PASS1_LDCXXFLAGS

  • 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.

• • -no-prec-div
  • 
  • PASS2_CXXFLAGS, PASS2_LDCXXFLAGS
  • (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.

• • -prof-use
  • 
  • PASS2_CXXFLAGS, PASS2_LDCXXFLAGS

  • 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

• • -ansi-alias
  • 
  • CXXOPTIMIZE

  • Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.

Fortran benchmarks

503.bwaves_r

• • basepeak = yes

549.fotonik3d_r

• • basepeak = yes

554.roms_r

• • basepeak = yes

Benchmarks using both Fortran and C

521.wrf_r

• • basepeak = yes

527.cam4_r

• • basepeak = yes

Benchmarks using both C and C++

• • -xCORE-AVX2
  • 
  • PASS2_CFLAGS, PASS2_CXXFLAGS, PASS2_LDCXXFLAGS

  • 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.

• • -prof-genthreadsafe
  • 
  • PASS1_CFLAGS, PASS1_CXXFLAGS, PASS1_LDCXXFLAGS

  • Produces an instrumented object file that includes the collection of PGO data on applications that use a high level of parallelism.

• • -ipo
  • 
  • PASS2_CFLAGS, PASS2_CXXFLAGS, PASS2_LDCXXFLAGS

  • 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_CFLAGS, PASS2_CXXFLAGS, PASS2_LDCXXFLAGS

  • 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
• • -par-num-threads=1
  • 
  • PASS1_CFLAGS, PASS1_CXXFLAGS, PASS1_LDCXXFLAGS

  • 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.

• • -no-prec-div
  • 
  • PASS2_CFLAGS, PASS2_CXXFLAGS, PASS2_LDCXXFLAGS
  • (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.

• • -prof-use
  • 
  • PASS2_CFLAGS, PASS2_CXXFLAGS, PASS2_LDCXXFLAGS

  • 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

• • -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.

• • -ansi-alias
  • 
  • COPTIMIZE, CXXOPTIMIZE

  • Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.

Benchmarks using Fortran, C, and C++

507.cactuBSSN_r

• • basepeak = yes