https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92712
--- Comment #8 from Marc Glisse <glisse at gcc dot gnu.org> --- (In reply to Jakub Jelinek from comment #6) > The suggestion I'll try to work on is to check if C isn't a plus/minus expr > with constant second operand that doesn't go in the other direction and thus > where the transformation isn't introducing UB. In the testcase, t-1 is computed in some unsigned type and then cast back to signed, so I don't think it will work. > I guess it should be enough to do this in match.pd though. Yes.
