------- Comment #21 from dominiq at lps dot ens dot fr 2009-08-28 12:01 ------- And finally the winner is -fstrict-overflow!
[ibook-dhum] lin/test% gfc -m64 -O2 -funsafe-math-optimizations air_db.f90 [ibook-dhum] lin/test% time a.out > /dev/null 6.472u 0.020s 0:06.50 99.8% 0+0k 0+2io 0pf+0w <=== bad [ibook-dhum] lin/test% gfc -m64 -O2 -funsafe-math-optimizations -fno-strict-overflow air_db.f90 [ibook-dhum] lin/test% time a.out > /dev/null 4.307u 0.016s 0:04.33 99.5% 0+0k 0+0io 0pf+0w <=== good [ibook-dhum] lin/test% gfc -m64 -O1 -funsafe-math-optimizations air_db.f90 [ibook-dhum] lin/test% time a.out > /dev/null 4.347u 0.016s 0:04.37 99.5% 0+0k 0+1io 0pf+0w <=== good [ibook-dhum] lin/test% gfc -m64 -O1 -funsafe-math-optimizations -fstrict-overflow air_db.f90 [ibook-dhum] lin/test% time a.out > /dev/null 5.962u 0.019s 0:05.99 99.6% 0+0k 0+2io 0pf+0w <=== bad -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40106
