http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59494
--- Comment #4 from Dominique d'Humieres <dominiq at lps dot ens.fr> --- > I believe that is the only reason for the different number of vector > additions. I don't think the number of packed double operations is changed, only the number of occurrences of the scanned regular expression: [Book15] f90/bug% gfc -S -mtune=generic -O3 -ffast-math -msse2 -fpredictive-commoning -ftree-vectorize -fdump-tree-optimized /opt/gcc/work/gcc/testsuite/gfortran.dg/vect/fast-math-mgrid-resid.f [Book15] f90/bug% egrep "vect_[^\n]*\+ " fast-math-mgrid-resid.f.169t.optimized | wc -l 13 [Book15] f90/bug% grep addpd fast-math-mgrid-resid.s | wc -l 23 [Book15] f90/bug% grep subpd fast-math-mgrid-resid.s | wc -l 4 [Book15] f90/bug% grep mulpd fast-math-mgrid-resid.s | wc -l 4 [Book15] f90/bug% gfc -S -O3 -ffast-math -msse2 -fpredictive-commoning -ftree-vectorize -fdump-tree-optimized /opt/gcc/work/gcc/testsuite/gfortran.dg/vect/fast-math-mgrid-resid.f [Book15] f90/bug% egrep "vect_[^\n]*\+ " fast-math-mgrid-resid.f.169t.optimized | wc -l 10 [Book15] f90/bug% grep addpd fast-math-mgrid-resid.s | wc -l 23 [Book15] f90/bug% grep subpd fast-math-mgrid-resid.s | wc -l 4 [Book15] f90/bug% grep mulpd fast-math-mgrid-resid.s | wc -l 4 > Well, I don't think configuring with arbitrary --with-cpu/tune is > a supported configuration for zero testsuite FAILs ...? The tested configurations x86_64-apple-darwin* (IIRC defaulting to --with-arch=core2 --with-cpu=core2) and x86_64-*-* configured with --with-arch=corei7 --with-cpu=corei7. I also hope forbidden configurations are rejected (as done for at least some compiling options).