http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53338
--- Comment #5 from Dominique d'Humieres <dominiq at lps dot ens.fr> 2012-05-14 09:21:41 UTC --- > 20% runtime regression in rnflow [1] happened in this timeframe, perhaps it > could be attributed to the patch, mentioned in Comment #2. This slowdown is caused by revision 187092 in the proc cptrf2. A further slowdown (~5%) is caused by revision 187340 in the proc evlrnf. While tracking these slowdowns I also noticed that for any revision compiling rnflow.f90 is slower if I use -O3 only compared to the use of -O2 only (cptrf2 seems the culprit). The best timings I get are when I compile evlrnf with '-O3 -ffast-math -funroll-loops'. I am planning to open some PRs about these findings which do not seem related to this one (unless someone beat me).
