[Bug c/112449] Arithmetic operations can produce signaling NaNs

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112449

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note mips and sh and a few other targets have the quiet bit meaning the
opposite.