https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118955
--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> --- I have also always wondered about that glibc guard, esp. it being the kitchen-sink fast-math guard rather than sth more specific (yep, we don't have anything for -funsafe-math-optimizations). That is, I suppose glibc does not set FP exception flags "correctly" either. Is there documentation on what you can expect from the glibc vector math functions with regard to IEEE conformance?