> def : Pat<(i64 (opaque (imm0_65535 imm:$src))), (MOVZWi imm:$src, 0)>; Sorry, that should certainly not be i64 in there. def : Pat<(i32 (opaque (imm0_65535 imm:$src))), (MOVZWi imm:$src, 0)>; is more likely. Tim.