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From: "aldyh at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/104986] [12 Regression] bogus writing 1 byte into a region of size 0 with -fwrapv and -O2 -fpeel-loops since r12-4698-gf6d012338bf87f42
Date: Wed, 23 Mar 2022 14:45:14 +0000 [thread overview]
Message-ID: <bug-104986-4-KKqc9pee4g@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-104986-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104986
--- Comment #4 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #3)
> This is peeling leaving us with unreachable code we warn on and somehow
> while figuring prephitmp_30 + -6 is -1 we don't figure nb_58 is zero on
> the path to bb9.
>
> I think I've seen this backward-forward dependency issue with ranger before
> in another missed optimization PR.
This is not ranger, but the legacy conditional folding in vr-values. It's the
test_for_singularity() code that turns x<=0 where x is [0,6] into x!=0.
next prev parent reply other threads:[~2022-03-23 14:45 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-19 17:07 [Bug middle-end/104986] New: [12 Regression] bogus writing 1 byte into a region of size 0 with -fwrapv and -O2 -fpeel-loops andres at anarazel dot de
2022-03-21 8:53 ` [Bug middle-end/104986] " rguenth at gcc dot gnu.org
2022-03-21 9:31 ` [Bug middle-end/104986] [12 Regression] bogus writing 1 byte into a region of size 0 with -fwrapv and -O2 -fpeel-loops since r12-4698-gf6d012338bf87f42 marxin at gcc dot gnu.org
2022-03-23 9:45 ` aldyh at gcc dot gnu.org
2022-03-23 13:05 ` rguenth at gcc dot gnu.org
2022-03-23 14:45 ` aldyh at gcc dot gnu.org [this message]
2022-03-23 14:46 ` amacleod at redhat dot com
2022-03-23 14:49 ` aldyh at gcc dot gnu.org
2022-03-23 14:58 ` amacleod at redhat dot com
2022-03-23 15:05 ` rguenth at gcc dot gnu.org
2022-04-19 5:20 ` jakub at gcc dot gnu.org
2022-05-06 8:33 ` [Bug middle-end/104986] [12/13 " jakub at gcc dot gnu.org
2022-07-26 12:38 ` rguenth at gcc dot gnu.org
2023-05-08 12:24 ` [Bug middle-end/104986] [12/13/14 " rguenth at gcc dot gnu.org
2023-09-02 20:02 ` pinskia at gcc dot gnu.org
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