http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48139
--- Comment #8 from Jeffrey Yasskin <jyasskin at gcc dot gnu.org> 2011-03-17 01:09:38 UTC --- Ah, I didn't check Posix, specifically http://pubs.opengroup.org/onlinepubs/9699919799/functions/lrint.html. I now agree that gcc can't optimize this without -fno-math-errno.