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From: "vincent-gcc at vinc17 dot net" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/80548] -Wmaybe-uninitialized false positive when an assignment is added
Date: Tue, 22 Nov 2022 10:07:54 +0000 [thread overview]
Message-ID: <bug-80548-4-6K6VaF1Lfe@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-80548-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80548
--- Comment #10 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
(In reply to Jeffrey A. Law from comment #9)
> These warnings are certainly sensitive to all kinds of things, so it's
> possible it's just gone latent. The only way to be sure would be to bisect
> all the work between gcc-12 and the trunk and pour over the dumps with a
> fine tooth comb. I would hazard a guess it was Aldy's backwards threader
> work, particularly around not bailing out too early for subpaths based on
> comments in the BZ, but one would have to bisect to be 100% sure.
The commit that made the warning disappear is actually the one fixing PR106754.
commit 0a4a2667dc115ca73b552fcabf8570620dfbe55f
Author: Richard Biener <rguenther@suse.de>
Date: 2022-09-06 13:46:00 +0200
tree-optimization/106754 - fix compute_control_dep_chain defect
The following handles the situation of a loop exit along the
control path to the PHI def or from there to the use in a different
way, aoviding premature abort of the walks as noticed in the two
cases where the exit is outermost (gcc.dg/uninit-pred-11.c) or
wrapped in a condition that is on the path (gcc.dg/uninit-pred-12.c).
Instead of handling such exits during recursion we now pick them
up in the parent when walking post-dominators. That requires an
additional post-dominator walk at the outermost level which is
facilitated by splitting out the walk to a helper function and
the existing wrapper added earlier.
The patch also removes the bogus early exit from
uninit_analysis::init_use_preds, fixing a simplified version
of the PR106155 testcase.
next prev parent reply other threads:[~2022-11-22 10:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-80548-4@http.gcc.gnu.org/bugzilla/>
2021-04-13 23:56 ` [Bug middle-end/80548] " msebor at gcc dot gnu.org
2021-11-30 14:09 ` [Bug tree-optimization/80548] " aldyh at gcc dot gnu.org
2021-11-30 14:20 ` aldyh at gcc dot gnu.org
2021-11-30 14:38 ` aldyh at gcc dot gnu.org
2021-12-01 16:03 ` aldyh at gcc dot gnu.org
2022-11-20 4:05 ` law at gcc dot gnu.org
2022-11-21 9:59 ` vincent-gcc at vinc17 dot net
2022-11-21 14:40 ` law at gcc dot gnu.org
2022-11-22 10:07 ` vincent-gcc at vinc17 dot net [this message]
2022-11-22 13:10 ` law at gcc dot gnu.org
2022-11-23 16:46 ` vincent-gcc at vinc17 dot net
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