Fix pragma error with gcc/4.8.4

[ndellingwood]

Error with gcc/4.8.4 and OpenMP backend
kokkos-kernels/src/blas/impl/KokkosBlas3_gemm_impl.hpp:343:0: error:
ignoring #pragma omp simd [-Werror=unknown-pragmas]

Fixed by adding preprocessor #if to remove the pragma if gnu compiler
less than 4.8.5

[ndellingwood]

Fix for #180

[ndellingwood]

Test results:

[ndellin@kokkos-dev TestAllSandia-spot]$ ../../scripts/test_all_sandia gcc/4.8.4 --build-list=OpenMP --skip-hwloc
Going to test compilers:  gcc/4.8.4
Testing compiler gcc/4.8.4
  Starting job gcc-4.8.4-OpenMP-release
  PASSED gcc-4.8.4-OpenMP-release
#######################################################
PASSED TESTS
#######################################################
gcc-4.8.4-OpenMP-release build_time=183 run_time=358
#######################################################
FAILED TESTS
#######################################################

[ndellingwood]

gcc/4.8.4 implements OpenMP version 3.1 which does not support simd constructs (at least nowhere to be found in reference here openmp3.1), hence the -Werror for unknown pragma.

Relevant to discussion in trilinos/Trilinos#2317.

[crtrott]

This probably is not correct for intel. You probably need to nest this, or alternatively add a OMP_SIMD_EXISTS or whatever variable inside of Kokkos_Macros.hpp (there are similar variables for other pragma features, model it based on those). But that would require a change in Kokkos ...

[ndellingwood]

@crtrott thanks for catch, just pushed fix. Rerunning with gcc and intel

[ndellingwood]

Updated test results:

[ndellin@kokkos-dev TestAllSandia-spot]$ ../../scripts/test_all_sandia gcc/4.8.4 intel/15.0.2 --build-list=OpenMP --skip-hwloc
Going to test compilers:  gcc/4.8.4 intel/15.0.2
Testing compiler gcc/4.8.4
Testing compiler intel/15.0.2
  Starting job gcc-4.8.4-OpenMP-release
  Starting job intel-15.0.2-OpenMP-release
  PASSED gcc-4.8.4-OpenMP-release
  PASSED intel-15.0.2-OpenMP-release
#######################################################
PASSED TESTS
#######################################################
gcc-4.8.4-OpenMP-release build_time=342 run_time=396
intel-15.0.2-OpenMP-release build_time=518 run_time=344
#######################################################

[srajama1]

Indenting preprocessors directives !