https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49884
Segher Boessenkool <segher at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |segher at gcc dot gnu.org --- Comment #2 from Segher Boessenkool <segher at gcc dot gnu.org> --- Hi, Can you reproduce this on any target in mainline GCC? That would help people reproduce this. You say you have (set (reg:HI) (ashift:HI (reg:HI) (const_int 16))) and that will set all of the reg:HI to 0, so the reg:QI will also be 0? You seem to expect something else though?