[Bug tree-optimization/109154] [13 regression] jump threading de-optimizes nested floating point comparisons

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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109154] [13 regression] jump threading de-optimizes nested floating point comparisons
Date: Mon, 27 Mar 2023 10:44:56 +0000	[thread overview]
Message-ID: <bug-109154-4-HjmtxnPyFN@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109154-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109154

--- Comment #17 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to rguenther@suse.de from comment #15)
> I think flushing denormals makes sense for "forward" propagation,

Well, it still hurts quite a lot exactly for the ranges around zero.
Given that most CPU honor it most of the time, I think asking users
to use -funsafe-math-optimizations/-ffast-math/-Ofast if they instruct
the CPU not to do that is fine (different situation is Alpha where it
is the default behavior).

> Given -ffast-math on x86 enables FTZ we'd have to be conservative there
> as well.  But OTOH we don't have any HONOR_DENORMALS or so?

We don't but that is roughly what my patch adds...

> Note the testcase in this PR was about -Ofast ...

Indeed, for ranges from comparisons we could ignore the flush_denormals_to_zero
calls always; guess we'd need to add some defaulted new flag to set, pass true
to it from
the comparisons and don't call it if the flag is set.
In addition or instead of the above patch.  Aldy?

next prev parent reply	other threads:[~2023-03-27 10:44 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-16 11:57 [Bug tree-optimization/109154] New: [13 regression] aarch64 -mcpu=neoverse-v1 microbude performance regression pgodbole at nvidia dot com
2023-03-16 13:11 ` [Bug tree-optimization/109154] " tnfchris at gcc dot gnu.org
2023-03-16 14:58 ` [Bug target/109154] " rguenth at gcc dot gnu.org
2023-03-16 17:03 ` tnfchris at gcc dot gnu.org
2023-03-16 17:03 ` [Bug target/109154] [13 regression] jump threading with de-optimizes nested floating point comparisons tnfchris at gcc dot gnu.org
2023-03-22 10:20 ` [Bug tree-optimization/109154] [13 regression] jump threading " aldyh at gcc dot gnu.org
2023-03-22 10:29 ` avieira at gcc dot gnu.org
2023-03-22 12:22 ` rguenth at gcc dot gnu.org
2023-03-22 12:42 ` rguenth at gcc dot gnu.org
2023-03-22 13:11 ` aldyh at gcc dot gnu.org
2023-03-22 14:00 ` amacleod at redhat dot com
2023-03-22 14:39 ` aldyh at gcc dot gnu.org
2023-03-27  8:09 ` rguenth at gcc dot gnu.org
2023-03-27  9:30 ` jakub at gcc dot gnu.org
2023-03-27  9:42 ` aldyh at gcc dot gnu.org
2023-03-27  9:44 ` jakub at gcc dot gnu.org
2023-03-27 10:18 ` rguenther at suse dot de
2023-03-27 10:40 ` jakub at gcc dot gnu.org
2023-03-27 10:44 ` jakub at gcc dot gnu.org [this message]
2023-03-27 10:54 ` rguenth at gcc dot gnu.org
2023-03-27 10:56 ` jakub at gcc dot gnu.org
2023-03-27 10:59 ` jakub at gcc dot gnu.org
2023-03-27 17:07 ` jakub at gcc dot gnu.org
2023-03-28  8:33 ` rguenth at gcc dot gnu.org
2023-03-28  9:01 ` cvs-commit at gcc dot gnu.org
2023-03-28 10:07 ` tnfchris at gcc dot gnu.org
2023-03-28 10:08 ` tnfchris at gcc dot gnu.org
2023-03-28 12:18 ` jakub at gcc dot gnu.org
2023-03-28 12:25 ` rguenth at gcc dot gnu.org
2023-03-28 12:42 ` rguenth at gcc dot gnu.org
2023-03-28 13:19 ` rguenth at gcc dot gnu.org
2023-03-28 13:44 ` jakub at gcc dot gnu.org
2023-03-28 13:52 ` jakub at gcc dot gnu.org
2023-03-28 15:31 ` amacleod at redhat dot com
2023-03-28 15:40 ` jakub at gcc dot gnu.org
2023-03-28 15:53 ` amacleod at redhat dot com
2023-03-28 15:58 ` jakub at gcc dot gnu.org
2023-03-28 16:42 ` amacleod at redhat dot com
2023-03-28 21:12 ` amacleod at redhat dot com
2023-03-29  6:33 ` cvs-commit at gcc dot gnu.org
2023-03-29  6:38 ` rguenth at gcc dot gnu.org
2023-03-29 22:41 ` amacleod at redhat dot com
2023-03-30 18:17 ` cvs-commit at gcc dot gnu.org
2023-04-05  9:28 ` tnfchris at gcc dot gnu.org
2023-04-05  9:34 ` ktkachov at gcc dot gnu.org
2023-04-11  9:36 ` rguenth at gcc dot gnu.org
2023-04-13 16:54 ` jakub at gcc dot gnu.org
2023-04-13 17:25 ` rguenther at suse dot de
2023-04-13 17:29 ` jakub at gcc dot gnu.org
2023-04-14 18:10 ` jakub at gcc dot gnu.org
2023-04-14 18:14 ` jakub at gcc dot gnu.org
2023-04-14 18:22 ` jakub at gcc dot gnu.org
2023-04-14 19:09 ` jakub at gcc dot gnu.org
2023-04-15 10:10 ` cvs-commit at gcc dot gnu.org
2023-04-17 11:07 ` jakub at gcc dot gnu.org
2023-04-25 18:32 ` [Bug tree-optimization/109154] [13/14 " tnfchris at gcc dot gnu.org
2023-04-25 18:34 ` jakub at gcc dot gnu.org
2023-04-26  6:58 ` rguenth at gcc dot gnu.org
2023-04-26  9:43 ` tnfchris at gcc dot gnu.org
2023-04-26 10:07 ` jakub at gcc dot gnu.org
2023-07-07 18:10 ` tnfchris at gcc dot gnu.org
2023-07-10  7:15 ` rguenth at gcc dot gnu.org
2023-07-10 10:33 ` tnfchris at gcc dot gnu.org
2023-07-10 10:46 ` rguenth at gcc dot gnu.org
2023-07-10 11:02 ` tnfchris at gcc dot gnu.org
2023-07-10 11:27 ` rguenth at gcc dot gnu.org
2023-07-10 11:49 ` tnfchris at gcc dot gnu.org
2023-07-14 10:22 ` cvs-commit at gcc dot gnu.org
2023-07-14 10:22 ` cvs-commit at gcc dot gnu.org
2023-07-27  9:25 ` rguenth at gcc dot gnu.org
2023-10-02 10:53 ` cvs-commit at gcc dot gnu.org
2023-10-18  8:54 ` cvs-commit at gcc dot gnu.org
2023-10-18  8:54 ` cvs-commit at gcc dot gnu.org
2023-10-18  8:54 ` cvs-commit at gcc dot gnu.org
2023-10-18  8:55 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:20 ` cvs-commit at gcc dot gnu.org
2023-11-09 14:25 ` [Bug tree-optimization/109154] [13 " tnfchris at gcc dot gnu.org

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