On Thu, Feb 6, 2014 at 2:21 PM, Tim Prince <n...@aol.com> wrote: > > On 2/6/2014 1:51 PM, Uros Bizjak wrote: >> >> Hello! >> >> 4.9 does not enable -ftree-vectorize for -O3 (and Ofast) anymore. Is >> this intentional? >> >> $/ssd/uros/gcc-build/gcc/xgcc -B /ssd/uros/gcc-build/gcc -O3 -Q >> --help=optimizers >> >> ... >> -ftree-vectorize [disabled] >> ... >> >> > I'm seeing vectorization but no output from -ftree-vectorizer-verbose,
use -fopt-info. The old option is deprecated. >and > no dot product vectorization inside omp parallel regions, with gcc g++ or > gfortran 4.9. Primary targets are cygwin64 and linux x86_64. > I've been unable to use -O3 vectorization with gcc, although it works with > gfortran and g++, so use gcc -O2 -ftree-vectorize together with additional > optimization flags which don't break. Reproducible case? David > I've made source code changes to take advantage of the new vectorization > with merge() and ? operators; while it's useful for -march=core-avx2, it's > sometimes a loss for -msse4.1. > gcc vectorization with #pragma omp parallel for simd is reasonably effective > in my tests only on 12 or more cores. > #pragma omp simd reduction(max: ) is giving correct results but poor > performance in my tests. > > You've probably seen my gcc testresults posts. The one major recent > improvement is the ability to skip cilkplus tests on targets where it's > totally unsupported. Without cilk_for et al. even on "supported" targets > cilkplus seems useless. > There are still lots of failing stabs tests on targets where those > apparently aren't supported. > > So there are some mysteries about what the developers intend. I suppose > this was posted on gcc list on account of such questions being ignored on > gcc-help. > > -- > Tim Prince >
