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From: Dan Carpenter <dan.carpenter@linaro.org>
To: David Laight <david.laight.linux@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Vincent Mailhol <mailhol@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nicolas Schier <nsc@kernel.org>,
	Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
	Chris Mason <clm@fb.com>, David Sterba <dsterba@suse.com>,
	linux-kbuild@vger.kernel.org, linux-sparse@vger.kernel.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
	dri-devel@lists.freedesktop.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 0/2] kbuild: remove gcc's -Wtype-limits
Date: Fri, 19 Dec 2025 10:08:16 +0300	[thread overview]
Message-ID: <aUT54I0fD0aqBVyw@stanley.mountain> (raw)
In-Reply-To: <20251218220651.5cdde06f@pumpkin>

On Thu, Dec 18, 2025 at 10:06:51PM +0000, David Laight wrote:
> On Fri, 19 Dec 2025 08:34:05 +1200
> Linus Torvalds <torvalds@linux-foundation.org> wrote:
> 
> > On Fri, 19 Dec 2025 at 08:26, David Laight <david.laight.linux@gmail.com> wrote:
> > >
> > > One possibility is to conditionally add _Pragma()  
> > 
> > No. That compiler warning is pure and utter garbage. I have pointed it
> > out fopr *years*, and compiler people don't get it.
> > 
> > So that warning just needs to die. It's shit. It's wrong.
> 
> True - especially for code like:
> 	if (x < 0 || x > limit)
> 		return ...
> where the code is correct even with 'accidental' conversion of a
> negative signed value to a large unsigned one.
> 
> clang seems to have a dozen similar warnings, all of which are a PITA
> for kernel code - like rejecting !(4 << 16).

In this example is 4 a literal or do we at least know that 4 is
non-zero?

I really thought I had a check for that in Smatch but I guess I
don't...

regards,
dan carpenter


  parent reply	other threads:[~2025-12-19  7:08 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-18 18:50 [PATCH 0/2] kbuild: remove gcc's -Wtype-limits Vincent Mailhol
2025-12-18 18:50 ` [PATCH 1/2] " Vincent Mailhol
2025-12-18 19:36   ` Dan Carpenter
2025-12-18 22:31     ` Vincent Mailhol
2025-12-19  6:56       ` Dan Carpenter
2025-12-19 22:21       ` Vincent Mailhol
2025-12-18 18:50 ` [PATCH 2/2] kbuild: cleanup local -Wno-type-limits exceptions Vincent Mailhol
2025-12-18 20:24   ` David Sterba
2025-12-18 20:26 ` [PATCH 0/2] kbuild: remove gcc's -Wtype-limits David Laight
2025-12-18 20:34   ` Linus Torvalds
2025-12-18 22:06     ` David Laight
2025-12-18 22:19       ` Linus Torvalds
2025-12-19  7:08       ` Dan Carpenter [this message]
2025-12-19  7:33 ` Nicolas Schier
2025-12-19 22:06   ` Vincent Mailhol

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