https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64099
--- Comment #7 from Dominique d'Humieres <dominiq at lps dot ens.fr> --- The first runtime increase (with '-Ofast') is due to r216728: [Book15] lin/test% /opt/gcc/gcc4.10p-216727p2/bin/gfortran -Ofast -fwhole-program fatigue.f90 [Book15] lin/test% time a.out > /dev/null 1.380u 0.001s 0:01.38 100.0% 0+0k 0+1io 0pf+0w [Book15] lin/test% /opt/gcc/gcc4.10p-216728p2/bin/gfortran -Ofast -fwhole-program fatigue.f90 [Book15] lin/test% time a.out > /dev/null 1.500u 0.001s 0:01.50 100.0% 0+0k 0+2io 0pf+0w I also confirm it for the test fatigue2.f90 of the pb11 test suite: [Book15] lin/test% /opt/gcc/gcc4.10p-216727p2/bin/gfortran -Ofast -fwhole-program fatigue2.f90 [Book15] lin/test% time a.out > /dev/null 28.473u 0.005s 0:28.48 99.9% 0+0k 0+3io 0pf+0w [Book15] lin/test% /opt/gcc/gcc4.10p-216728p2/bin/gfortran -Ofast -fwhole-program fatigue2.f90 [Book15] lin/test% time a.out > /dev/null 30.699u 0.006s 0:30.71 99.9% 0+0k 0+1io 40pf+0w [Book15] lin/test% /opt/gcc/gcc4.10p-217825p1/bin/gfortran -Ofast -fwhole-program fatigue2.f90 [Book15] lin/test% time a.out > /dev/null 30.840u 0.006s 0:30.84 100.0% 0+0k 0+4io 0pf+0w [Book15] lin/test% /opt/gcc/gcc4.10p-217827p1/bin/gfortran -Ofast -fwhole-program fatigue2.f90 [Book15] lin/test% time a.out > /dev/null 33.387u 0.005s 0:33.39 99.9% 0+0k 0+2io 0pf+0w [Book15] lin/test% /opt/gcc/gcc4.10p-217825p1/bin/gfortran -O3 -ffast-math -fwhole-program fatigue2.f90 [Book15] lin/test% time a.out > /dev/null 54.750u 0.013s 0:54.77 99.9% 0+0k 0+6io 41pf+0w [Book15] lin/test% /opt/gcc/gcc4.10p-217827p1/bin/gfortran -O3 -ffast-math -fwhole-program fatigue2.f90 [Book15] lin/test% time a.out > /dev/null 62.117u 0.039s 1:02.18 99.9% 0+0k 1+6io 53pf+0w
