Phoronix numbers for clang-omp compiler

Jack,
Actually everything is quite simple. Config files for Phoronix test suites are using gcc by default and -O2 is provided by default in this config files. I think they just compiled these tests by gcc with the default config (which already includes -O2) while for clang they had to specify some custom options (like "-fopenmp -lgomp", though the second one is not needed), but forget to add any optimization options.

Best regards,
Alexey Bataev

Alexey,
This wouldn’t be the first time that Phoronix has gotten sloppy with using a common set of optimization flags in their gcc vs clang benchmarks. Although, it is getting harder to make direct comparisons. Clang now autovectorizes at -O2 while, as you can see from the my prior posting of the assembly from-fverbose-asm -O2, FSF gcc 4.9.0 doesn’t.
Jack

Jack,
Yes, this is true, but I don't think that it is a good idea to compare performance between code compiled with -O2 and compiled with -O0.

Best regards,
Alexey Bataev