https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81906
--- Comment #3 from Vadim Zeitlin <vz-gcc at zeitlins dot org> --- (In reply to Andrew Pinski from comment #1) > You want -frounding-math OK, thanks, this does indeed solve my immediate problem. However is it really normal that the compiler behaviour silently (!) changes like this, in backwards incompatible way between versions? I didn't remember seeing this change mentioned in gcc 6 release notes and I just reread them again and can't find it anywhere. I think changes silently breaking existing working (and standard conforming) code should be at the very least prominently documented (and, of course, ideally completely avoided IMO, but this ship has probably already sailed).