From: Jeff Law via Libc-alpha <libc-alpha@sourceware.org>
To: Aldy Hernandez <aldyh@redhat.com>,
Joseph Myers <joseph@codesourcery.com>
Cc: "MacLeod, Andrew" <amacleod@redhat.com>,
GCC Mailing List <gcc@gcc.gnu.org>,
Martin Sebor <msebor@redhat.com>,
libc-alpha@sourceware.org
Subject: Re: Failures building glibc with mainline GCC
Date: Fri, 30 Jul 2021 10:22:17 -0600 [thread overview]
Message-ID: <b4ad3261-6ccc-2a8c-c32f-285812b73374@gmail.com> (raw)
In-Reply-To: <CAGm3qMURZ-m37CpxAdkvao3Y3KbKPTmV0HYgFhsuMrkZJ17CbQ@mail.gmail.com>
On 7/30/2021 10:19 AM, Aldy Hernandez via Libc-alpha wrote:
> There's a new jump threader in GCC which is much more aggressive, and
> may trigger latent problems with other warning passes, especially
> -Warray-bounds, -Woverflow, and -Wuninitialized.
>
> Do your problems go away if you take out commit 2e96b5f14e?
>
> I have notes throughout the commit analyzing variants of the above
> warnings (for example my addendum to gcc.c-torture/compile/pr83510.c).
> So far, all the warnings I've seen are legitimate jump threading
> opportunities that we are now doing, but which throw off the warning
> passes.
>
> Before the inclusion of the new threader, I had warned that this could
> happen. Perhaps we'll have to come up a way to reduce the false
> positives.
I should be able to get you testcases for at least some of these. I
strongly suspect it's the new threader. First up will be the iconf
stringop-overflow failures which should hit your inbox shortly.
Jeff
next prev parent reply other threads:[~2021-07-30 16:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-30 15:30 Failures building glibc with mainline GCC Joseph Myers
2021-07-30 16:19 ` Aldy Hernandez via Libc-alpha
2021-07-30 16:22 ` Jeff Law via Libc-alpha [this message]
2021-07-30 16:45 ` Jeff Law via Libc-alpha
2021-07-30 17:28 ` Martin Sebor via Libc-alpha
2021-07-30 20:52 ` Joseph Myers
2021-08-02 20:20 ` Martin Sebor via Libc-alpha
2021-08-03 15:54 ` Joseph Myers
2021-08-03 16:20 ` Martin Sebor via Libc-alpha
2021-08-03 17:21 ` Joseph Myers
2021-08-03 17:39 ` Samuel Thibault via Libc-alpha
2021-08-03 22:33 ` Martin Sebor via Libc-alpha
2021-08-03 20:50 ` Segher Boessenkool
2021-08-03 21:00 ` Joseph Myers
2021-08-03 22:02 ` Segher Boessenkool
2021-08-03 22:59 ` Martin Sebor via Libc-alpha
2021-07-30 16:38 ` Joseph Myers
2021-07-30 16:43 ` Jakub Jelinek via Libc-alpha
2021-07-30 16:53 ` Martin Sebor via Libc-alpha
2021-07-30 17:02 ` Jakub Jelinek via Libc-alpha
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