https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102239
Segher Boessenkool <segher at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2021-09-09 Ever confirmed|0 |1 Status|UNCONFIRMED |NEW --- Comment #1 from Segher Boessenkool <segher at gcc dot gnu.org> --- Confirmed. So the relevant insn (parallel [(set (reg:CC 123) (compare:CC (and:DI (reg:DI 124) (const_int 25769803776 [0x600000000])) (const_int 0 [0]))) (clobber (scratch:DI))]) is matched by *and<mode>3_2insn but not by any pattern that ends up as just one insn. Not *and<mode>3_mask_dot, because that doesn't do a shift first, is just an AND and there are no machine insns to do that; but there is no pattern for what we can do. *rotl<mode>3_mask_dot cannot do this either; the base and the dot2 of that cannot be done, they return a shifted result, but that doesn't matter for comparing it to 0. So we should add a specialised version.