https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68008
--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> --- Probably not related, but at -O2, I notice that sccp produces the "interesting": _3 = n_4(D) + -2; _12 = (unsigned int) n_4(D); _10 = _12 + 4294967294; _2 = _10 / 2; _11 = (int) _2; _9 = _11 * -2; _17 = _3 + _9; (n is of type int) which we don't simplify at gimple level (looks like we do in RTL). Even with the X+(X/Y)*-Y thing that is in review (and assuming it supports convert in the right places, which may not be the case), it would require at least CSE-ing _10 to (unsigned int) _3. Well, maybe since 2 is a power of 2, we could simplify _9 = _10 & -2; and depending on which representation is preferred, (n-2)&-2 might become (n&-2)-2 and we might eventually get there, but that would be very fragile.
