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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/106884] ifcombine may move shift so it shifts more than bitwidth
Date: Tue, 11 Jul 2023 15:36:45 +0000 [thread overview]
Message-ID: <bug-106884-4-7rPGNM5lC5@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-106884-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106884
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #4)
> But yes, since we now unconditionally compute 1<<b after the transform
> GCC could assume b is in range. We are lacking a way to compute 1<<b
> optimally without that undefined behavior.
phiopt will almost definitely run into a similar thing though right now, it has
not.
next prev parent reply other threads:[~2023-07-11 15:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-08 0:20 [Bug tree-optimization/106884] New: " kristerw at gcc dot gnu.org
2022-09-08 9:52 ` [Bug tree-optimization/106884] " rguenth at gcc dot gnu.org
2022-09-08 10:53 ` kristerw at gcc dot gnu.org
2022-09-30 11:34 ` kristerw at gcc dot gnu.org
2023-07-11 9:45 ` rguenth at gcc dot gnu.org
2023-07-11 15:36 ` pinskia at gcc dot gnu.org [this message]
2023-08-06 0:07 ` kristerw at gcc dot gnu.org
2023-11-01 15:57 ` pinskia at gcc dot gnu.org
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