https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70703
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Vlad, any thoughts on this? I'll try to deal with this in the widening_mul pass too, that pass converts: _1 = (long long unsigned int) x_4(D); - _2 = _1 * 6700417; + _2 = x_4(D) w* 6700417; _3 = _2 >> 32; _5 = (unsigned int) _3; but as the only user cares about the high part of the widened result, we could convert it into: _1 = (long long unsigned int) x_4(D); _2 = _1 * 6700417; _3 = _2 >> 32; - _5 = (unsigned int) _3; + _5 = x_4(D) h* 6700417; There is nothing that would attempt match.pd foldings after this.