3 ms·
Interesting. Would this be safer in a language like Fortran, where (without aliasing between separate arrays), loop dependencies should be more obvious? I thin
by celrod 7y ago
Interesting.
Would this be safer in a language like Fortran, where (without aliasing between separate arrays), loop dependencies should be more obvious?
I think it'd be nice to be able to activate this mode through pragmas.
Does "#pragma omp simd" result in more aggressive use of blocking?
- gnufx 7y agoI don't know how omp simd is related to "blocking", but it can slow code by a factor of two compared with GCC optimizing the loop normally, because you get AVX(51)2 but not FMA. (Observed with a generic C GEMM, which got about 60% of the micro-optimized one after removing such pragmas and just letting gcc do its -Ofast thing.)