[Bug tree-optimization/127455] Unsigned casts prevent folding bit-mask MAX

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127455

--- Comment #1 from Drea Pinski <pinskia at gcc dot gnu.org> ---
It should be easy to add an optional nop_convert.