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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/102793] AArch64: sequential comparisons with equal conditional blocks don't use ccmp Date: Mon, 18 Oct 2021 06:43:44 +0000 [thread overview] Message-ID: <bug-102793-4-SMQbCxFgjo@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-102793-4@http.gcc.gnu.org/bugzilla/> 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.
next prev parent reply other threads:[~2021-10-18 6:43 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-10-15 21:07 [Bug target/102793] New: " christophm30 at gmail dot com 2021-10-15 21:10 ` [Bug tree-optimization/102793] " pinskia at gcc dot gnu.org 2021-10-15 21:19 ` pinskia at gcc dot gnu.org 2021-10-18 6:35 ` rguenth at gcc dot gnu.org 2021-10-18 6:43 ` pinskia at gcc dot gnu.org [this message] 2023-08-26 7:27 ` pinskia at gcc dot gnu.org 2024-04-05 12:35 ` manolis.tsamis at vrull dot eu 2024-04-05 12:41 ` manolis.tsamis at vrull dot eu
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