https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65153
--- Comment #9 from Oleg Endo <olegendo at gcc dot gnu.org> --- (In reply to Oleg Endo from comment #8) > > I've tried to disable the peephole on trunk and compared CSiBE results. It > seems the peephole doesn't hit very often: > sum: 3371887 -> 3371943 +56 / +0.001661 % > > So we could probably remove the complex peephole without a big loss. > > I have a set of similar but simpler peepholes with a higher hit rate. Maybe > we can replace the complex peephole with some simpler ones. The set of peepholes can be found in PR 61142, attachment 34839. CSiBE numbers with that patch: sum: 3371887 -> 3367967 -3920 / -0.116255 % avg: -217.777778 / -0.167780 % max: replaypc-0.4.0.preproc 57212 -> 57188 -24 / -0.041949 % min: mpeg2dec-0.3.1 54348 -> 53984 -364 / -0.669758 % and with the patch, but without the problematic peephole of this PR: sum: 3371887 -> 3367983 -3904 / -0.115781 % avg: -216.888889 / -0.167686 % max: replaypc-0.4.0.preproc 57212 -> 57188 -24 / -0.041949 % min: mpeg2dec-0.3.1 54348 -> 53984 -364 / -0.669758 % It seems that the other set of peepholes covers most of the cases of the complex peephole.
