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From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/103088] [12 regression] 500.perlbench from spec 2017 fails since r12-4698 Date: Mon, 22 Nov 2021 07:37:46 +0000 [thread overview] Message-ID: <bug-103088-4-OiP9JEnhuh@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-103088-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103088 --- Comment #22 from rguenther at suse dot de <rguenther at suse dot de> --- On Fri, 19 Nov 2021, aldyh at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103088 > > --- Comment #19 from Aldy Hernandez <aldyh at gcc dot gnu.org> --- > > The problem is this construct in Perl_do_ncmp: > > if (lnv < rnv) > return -1; > if (lnv > rnv) > return 1; > if (lnv == rnv) > return 0; > return 2; > > These are all doubles. The code is depending on a pair of values that are > neither <, >, nor ==, being a NAN. It would be nice from a QOI point of view (aka DWIM) that even with -ffast-math we'd recognize this as a form of FP classification since "obviously" the intent was to handle the NaN special case. Not that I see any reasonable way to represent the NaN case in -ffast-math IL ... > I think we can keep this PR closed. Don't use -ffast-math unless followed by > -fno-unsafe-math-optimizations. Agreed.
next prev parent reply other threads:[~2021-11-22 7:37 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-04 20:45 [Bug other/103088] New: " seurer at gcc dot gnu.org 2021-11-05 7:25 ` [Bug tree-optimization/103088] " rguenth at gcc dot gnu.org 2021-11-05 11:26 ` marxin at gcc dot gnu.org 2021-11-05 13:35 ` rguenth at gcc dot gnu.org 2021-11-05 14:19 ` seurer at gcc dot gnu.org 2021-11-17 15:28 ` tnfchris at gcc dot gnu.org 2021-11-17 17:48 ` aldyh at gcc dot gnu.org 2021-11-17 17:53 ` tnfchris at gcc dot gnu.org 2021-11-17 18:58 ` seurer at gcc dot gnu.org 2021-11-18 16:35 ` aldyh at gcc dot gnu.org 2021-11-18 16:45 ` tnfchris at gcc dot gnu.org 2021-11-18 19:13 ` aldyh at gcc dot gnu.org 2021-11-19 7:06 ` rguenther at suse dot de 2021-11-19 8:10 ` tnfchris at gcc dot gnu.org 2021-11-19 8:14 ` rguenth at gcc dot gnu.org 2021-11-19 10:09 ` aldyh at gcc dot gnu.org 2021-11-19 11:40 ` marxin at gcc dot gnu.org 2021-11-19 11:47 ` aldyh at gcc dot gnu.org 2021-11-19 11:58 ` tnfchris at gcc dot gnu.org 2021-11-19 12:27 ` marxin at gcc dot gnu.org 2021-11-19 12:33 ` tnfchris at gcc dot gnu.org 2021-11-19 16:11 ` aldyh at gcc dot gnu.org 2021-11-19 16:14 ` aldyh at gcc dot gnu.org 2021-11-21 19:37 ` aldyh at gcc dot gnu.org 2021-11-22 7:37 ` rguenther at suse dot de [this message] 2021-11-23 7:38 ` tnfchris at gcc dot gnu.org 2021-11-29 16:35 ` segher at gcc dot gnu.org 2024-05-02 21:31 ` pinskia at gcc dot gnu.org
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