[Bug target/94135] PPC: subfic instead of neg used for rotate right

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94135

--- Comment #5 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Please try it out on hardware (or on a cycle-accurate simulator) if you don't
believe me ;-)