https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91720
--- Comment #3 from Eric Botcazou <ebotcazou at gcc dot gnu.org> --- > So, the bug is either in nonzero_bits that it for the > WORD_REGISTER_OPERATIONS and load_extend_op (QImode) == ZERO_EXTEND returns > 0s in the upper bits, or in > simplify_and_const_int trusting nonzero_bits even on paradoxical subregs, ... As Jim said on gcc-patches@, let's concede defeat for WORD_REGISTER_OPERATIONS and just remove it from the compiler. This will pessimize but I'm personally fed up with this endless stream of nonsensical bug reports with dozens of improbable -fno-xxxx switches...
