[Bug c/123987] isinfl isinff incorrectly for x86 and arm64

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123987

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
You want to look a thttps://man7.org/linux/man-pages/man3/fpclassify.3.html
btw.