https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82447
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> --- (In reply to amker from comment #4) > (In reply to Jakub Jelinek from comment #2) > > Indeed. But when the body is: > > sum += a[size - 1 - i]; > > while base 128U with step -1U is considered, it isn't found as the cheapest > > for some reason either. > > On 64-bit targets, candidate [128, -1] is added in unsigned int type, while > address IV has pointer type. IVOPTs simply skips the candidate because it > has smaller precision than the IV use. Yeah, but can't we also add [128UL, -1UL] candidate if we see there are IVs of that bitsize? Conversion from that to the unsigned int IV is cheap.
