[Bug tree-optimization/91734] gcc skip an if statement with "-O1 -ffast-math"

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91734

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
flag_unsafe_math_optimizations "trumps" everything to some extent, so yes,
I'd say -funsafe-math-optimizations -frounding-math doesn't make much sense.