https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80304
--- Comment #2 from Chinoune <chinoune.mehdi at hotmail dot com> --- (In reply to Dominique d'Humieres from comment #1) > WORKSFORME on x86_64-apple-darwin16 from 4.8 up to trunk (7.0): > > 10.0000000 6.00000000 > 10.0000000 6.00000000 > 10.0000000 6.00000000 it works well without optimization. did you use the optimization directives : -Ox ( -O1,-O2,-O3 ..)