From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Guenter Roeck <linux@roeck-us.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
dri-devel@lists.freedesktop.org,
linux-toolchains@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: Linux 6.3-rc3
Date: Mon, 20 Mar 2023 17:48:40 -0500 [thread overview]
Message-ID: <20230320224840.GG25951@gate.crashing.org> (raw)
In-Reply-To: <20230320220631.GA637514@dev-arch.thelio-3990X>
On Mon, Mar 20, 2023 at 03:06:31PM -0700, Nathan Chancellor wrote:
> It seems like clang takes into account that the branch has no effect on
> how uninitialized err is, although it does acknowledge there may be
> control flow where err is not used uninitialized because it is not used
> at all by stating "when used here". I guess GCC does not make this
> distinction and places it under -Wmaybe-uninitialized. I could be
> totally wrong though :)
In one place we have the comment
/* Re-do the plain uninitialized variable check, as optimization may have
straightened control flow. Do this first so that we don't accidentally
get a "may be" warning when we'd have seen an "is" warning later. */
It seems we miss a similar case here?
In any case, please open a PR if you want this fixed. Thanks!
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: linux-toolchains@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
llvm@lists.linux.dev,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
dri-devel@lists.freedesktop.org,
Guenter Roeck <linux@roeck-us.net>
Subject: Re: Linux 6.3-rc3
Date: Mon, 20 Mar 2023 17:48:40 -0500 [thread overview]
Message-ID: <20230320224840.GG25951@gate.crashing.org> (raw)
In-Reply-To: <20230320220631.GA637514@dev-arch.thelio-3990X>
On Mon, Mar 20, 2023 at 03:06:31PM -0700, Nathan Chancellor wrote:
> It seems like clang takes into account that the branch has no effect on
> how uninitialized err is, although it does acknowledge there may be
> control flow where err is not used uninitialized because it is not used
> at all by stating "when used here". I guess GCC does not make this
> distinction and places it under -Wmaybe-uninitialized. I could be
> totally wrong though :)
In one place we have the comment
/* Re-do the plain uninitialized variable check, as optimization may have
straightened control flow. Do this first so that we don't accidentally
get a "may be" warning when we'd have seen an "is" warning later. */
It seems we miss a similar case here?
In any case, please open a PR if you want this fixed. Thanks!
Segher
next prev parent reply other threads:[~2023-03-20 22:54 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-19 20:50 Linux 6.3-rc3 Linus Torvalds
2023-03-20 8:21 ` Build regressions/improvements in v6.3-rc3 Geert Uytterhoeven
2023-03-21 5:38 ` Build regressions/improvements in v6.3-rc3 (drm/msm/) Randy Dunlap
2023-03-21 5:38 ` Randy Dunlap
2023-03-21 7:34 ` Geert Uytterhoeven
2023-03-21 7:34 ` Geert Uytterhoeven
2023-03-21 15:10 ` Randy Dunlap
2023-03-21 15:10 ` Randy Dunlap
2023-03-21 15:33 ` Geert Uytterhoeven
2023-03-21 15:33 ` Geert Uytterhoeven
2023-03-20 18:05 ` Linux 6.3-rc3 Nathan Chancellor
2023-03-20 18:05 ` Nathan Chancellor
2023-03-20 18:26 ` Linus Torvalds
2023-03-20 18:26 ` Linus Torvalds
2023-03-20 18:49 ` Linus Torvalds
2023-03-20 18:49 ` Linus Torvalds
2023-03-20 18:56 ` Nathan Chancellor
2023-03-20 18:56 ` Nathan Chancellor
2023-03-20 19:05 ` Linus Torvalds
2023-03-20 19:05 ` Linus Torvalds
2023-03-20 18:53 ` Nathan Chancellor
2023-03-20 18:53 ` Nathan Chancellor
2023-03-20 19:22 ` Nathan Chancellor
2023-03-20 19:22 ` Nathan Chancellor
2023-03-22 12:44 ` Kalle Valo
2023-03-22 12:44 ` Kalle Valo
2023-03-22 16:36 ` Nathan Chancellor
2023-03-22 16:36 ` Nathan Chancellor
2023-03-22 20:36 ` Nathan Chancellor
2023-03-22 20:36 ` Nathan Chancellor
2023-03-24 10:54 ` Kalle Valo
2023-03-24 10:54 ` Kalle Valo
2023-03-24 15:11 ` Nathan Chancellor
2023-03-24 15:11 ` Nathan Chancellor
2023-03-24 15:23 ` Kalle Valo
2023-03-24 15:23 ` Kalle Valo
2023-03-28 19:07 ` Nathan Chancellor
2023-03-28 19:07 ` Nathan Chancellor
2023-03-29 8:39 ` Kalle Valo
2023-03-29 8:39 ` Kalle Valo
2023-03-22 16:40 ` Sedat Dilek
2023-03-22 16:40 ` Sedat Dilek
2023-03-22 16:55 ` Linus Torvalds
2023-03-22 16:55 ` Linus Torvalds
2023-03-22 18:17 ` Nick Desaulniers
2023-03-22 18:17 ` Nick Desaulniers
2023-03-24 17:16 ` Masahiro Yamada
2023-03-24 17:16 ` Masahiro Yamada
2023-03-27 16:12 ` Jani Nikula
2023-03-27 16:12 ` Jani Nikula
2023-03-27 17:03 ` Kalle Valo
2023-03-27 17:03 ` Kalle Valo
2023-03-20 20:04 ` Guenter Roeck
2023-03-20 20:04 ` Guenter Roeck
2023-03-20 20:30 ` Linus Torvalds
2023-03-20 20:30 ` Linus Torvalds
2023-03-20 22:06 ` Nathan Chancellor
2023-03-20 22:06 ` Nathan Chancellor
2023-03-20 22:48 ` Segher Boessenkool [this message]
2023-03-20 22:48 ` Segher Boessenkool
2023-03-20 23:41 ` Linus Torvalds
2023-03-20 23:41 ` Linus Torvalds
2023-03-24 9:41 ` Daniel Vetter
2023-03-24 9:41 ` Daniel Vetter
2023-03-20 20:07 ` Guenter Roeck
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