https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102793
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Richard Biener from comment #3) > I wonder why tail-merging doesn't do it's job here. It does (on > x86_64-linux): Oh I missed that. > but what's missing is possibly some if-combine? Yes because ifcombine happens way way too early. I wonder if we should not have another one or move the currently one to be after the loop optimizations are done. > IMHO ccmp expansion should be re-written to a pre RTL expansion GIMPLE > transform. basically ccmp expension is just ifcombine really. That is: cc = bar cmp 0 cc = cc.eq ? ne : d1 cmp d2 cset cc.ne So this is why doing a late pass ifcombine might be good for aarch64; I don't know if how much compile time it would cost though.
