OMP2012 Flag Description
IBM IBM S822LC for HPC (Power8 with NVLink, 2.860 GHz)

Base Optimization Flags

C benchmarks

• • -Ofast
  • 
  • COPTIMIZE

  • Disregard strict standards compliance. -Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs. It turns on -ffast-math and the Fortran-specific -fno-protect-parens and -fstack-arrays.

• • -fopenmp
  • 
  • COPTIMIZE

  • Enable handling of OpenMP directives "#pragma omp" in C/C++ and "!$omp" in Fortran. When -fopenmp is specified, the compiler generates parallel code according to the OpenMP Application Program Interface v4.0 . This option implies -pthread, and thus is only supported on targets that have support for -pthread. -fopenmp implies -fopenmp-simd.

• • -fsigned-char
  • 
  • clang, clangplusplus
  • COPTIMIZE

  • specifies signed char characters. The compiler treats "plain" char declarations as signed char.

C++ benchmarks

• • -Ofast
  • 
  • CXXOPTIMIZE

  • Disregard strict standards compliance. -Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs. It turns on -ffast-math and the Fortran-specific -fno-protect-parens and -fstack-arrays.

• • -fopenmp
  • 
  • CXXOPTIMIZE

  • Enable handling of OpenMP directives "#pragma omp" in C/C++ and "!$omp" in Fortran. When -fopenmp is specified, the compiler generates parallel code according to the OpenMP Application Program Interface v4.0 . This option implies -pthread, and thus is only supported on targets that have support for -pthread. -fopenmp implies -fopenmp-simd.

Fortran benchmarks

• • -Ofast
  • 
  • FOPTIMIZE

  • Disregard strict standards compliance. -Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs. It turns on -ffast-math and the Fortran-specific -fno-protect-parens and -fstack-arrays.

• • -fopenmp
  • 
  • FOPTIMIZE

  • Enable handling of OpenMP directives "#pragma omp" in C/C++ and "!$omp" in Fortran. When -fopenmp is specified, the compiler generates parallel code according to the OpenMP Application Program Interface v4.0 . This option implies -pthread, and thus is only supported on targets that have support for -pthread. -fopenmp implies -fopenmp-simd.