https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78379
--- Comment #10 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> --- (In reply to Thomas Koenig from comment #9) > Next question - what happens if you add > > -mvzeroupper -mavx > > to the line in the Makefile? Does that make a difference in speed? -mvzeroupper slows all way down with or without -mprefer-avx128
