etmc/tmLQCD — pull request #191 by kostrzewa (2012-12-11 16:17:07+00:00)
Title: change optimization flags for PowerPC targets as a safety measure

do not use -O3 on PowerPC because it leads to wrong results on BG/Q when... not using -qstrict=all (even -qstrict does not help)

I got a bit confused today because I compiled on BG/Q and suddenly had NaN everywhere. It turns out I had an unlucky combination of optimization flags which meant that -qstrict and -O3 were being used. Unless -qstrict=all is used, -O3 is not safe on BG/Q!