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From: "marxin at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/102902] [12 Regression] -O3 produces code that uses an uninitialized variable but originally was not used by r12-3876
Date: Mon, 25 Oct 2021 08:57:41 +0000 [thread overview]
Message-ID: <bug-102902-4-VrZxGjWXv9@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102902-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102902
--- Comment #4 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to Martin Liška from comment #3)
> I guess fixed with:
>
> commit aa15952d646fd5dd569fce287b719a737ae66e4f (HEAD -> master,
> origin/trunk, origin/master, origin/HEAD)
> Author: Richard Biener <rguenther@suse.de>
> Date: Mon Oct 25 09:33:15 2021 +0200
>
> tree-optimization/102920 - fix PHI VN with undefined args
>
> This fixes a latent issue exposed by now allowing VN_TOP in PHI
> arguments. We may only use optimistic equality when merging values on
> different edges, not when merging values on the same edge - in particular
> we may not choose the undef value on any edge when there's a not undef
> value as well.
>
> 2021-10-25 Richard Biener <rguenther@suse.de>
>
> PR tree-optimization/102920
> * tree-ssa-sccvn.h (expressions_equal_p): Add argument
> controlling VN_TOP matching behavior.
> * tree-ssa-sccvn.c (expressions_equal_p): Likewise.
> (vn_phi_eq): Do not optimistically match VN_TOP.
>
> * gcc.dg/torture/pr102920.c: New testcase.
Sorry, wrong PR.
next prev parent reply other threads:[~2021-10-25 8:57 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-22 17:35 [Bug tree-optimization/102902] New: wrong code at -O3 on x86_64-linux-gnu (generated code hangs) zhendong.su at inf dot ethz.ch
2021-10-22 18:53 ` [Bug tree-optimization/102902] [12 Regression] " pinskia at gcc dot gnu.org
2021-10-22 21:20 ` pinskia at gcc dot gnu.org
2021-10-25 8:44 ` [Bug tree-optimization/102902] [12 Regression] -O3 produces code that uses an uninitialized variable but originally was not used by r12-3876 marxin at gcc dot gnu.org
2021-10-25 8:45 ` marxin at gcc dot gnu.org
2021-10-25 8:57 ` marxin at gcc dot gnu.org [this message]
2021-10-25 8:58 ` rguenth at gcc dot gnu.org
2021-11-24 8:35 ` zhendong.su at inf dot ethz.ch
2021-11-24 8:44 ` pinskia at gcc dot gnu.org
2021-11-24 8:46 ` pinskia at gcc dot gnu.org
2022-01-17 13:09 ` rguenth at gcc dot gnu.org
2022-04-04 12:59 ` rguenth at gcc dot gnu.org
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