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From: Markus Trippelsdorf <markus@trippelsdorf.de>
To: Borislav Petkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Sam Ravnborg <sam@ravnborg.org>,
	lkml <linux-kernel@vger.kernel.org>, Michael Matz <matz@suse.de>,
	linux-kbuild@vger.kernel.org, x86-ml <x86@kernel.org>
Subject: Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1
Date: Thu, 28 Jul 2016 19:56:47 +0200	[thread overview]
Message-ID: <20160728175647.GB316@x4> (raw)
In-Reply-To: <20160728084624.GA30084@nazgul.tnic>

On 2016.07.28 at 10:46 +0200, Borislav Petkov wrote:
> On Thu, Jul 28, 2016 at 10:29:15AM +0200, Ingo Molnar wrote:
> > BUT, isn't this the natural state of things, that the 'final' warnings
> > that don't get fixed are the obnoxious, false positive ones - because
> > anyone who looks at them will say "oh crap, idiotic compiler!"?
> 
> Hmm, so my experience is like Linus' - that -Wmaybe thing generates too
> much noise and a lot of false positives. The thing is, as Micha (on CC)
> explained it to me, that warning simply says that GCC sometimes *cannot*
> know whether the variable will be used uninitialized or not and eagerly
> issues the warning message, just in case.

Another issue is that the number of warnings you get depend on the
optimization level. So -Os may be different from -O2 and once you use
-O3 (I know it is not officially supported) you will drown in false
positives...

-- 
Markus

  parent reply	other threads:[~2016-07-28 18:03 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-16 13:20 [RFC] Turn off -Wmaybe-uninitialized completely and move it to W=1 Borislav Petkov
2014-06-16 21:14 ` Sam Ravnborg
2014-06-24 21:38   ` [PATCH] Kbuild: Move -Wmaybe-uninitialized " Borislav Petkov
2014-07-07 10:53     ` Borislav Petkov
2014-07-08  9:25       ` Paul Bolle
2014-07-08 11:37         ` Borislav Petkov
2014-07-10 10:42           ` Borislav Petkov
2014-07-10 11:03             ` Paul Bolle
2016-07-28  4:20       ` Borislav Petkov
2016-07-28  8:29         ` Ingo Molnar
2016-07-28  8:46           ` Borislav Petkov
2016-07-28 16:49             ` Ingo Molnar
2016-07-28 17:04               ` Ingo Molnar
2016-07-28 17:56             ` Markus Trippelsdorf [this message]
2016-07-28 19:03           ` Linus Torvalds
2016-07-28 19:08             ` Linus Torvalds
2016-07-28 20:28               ` Ingo Molnar
2016-07-28 21:22             ` Linus Torvalds
2016-07-29 10:08               ` Arnd Bergmann
2016-07-29 10:19                 ` Borislav Petkov
2016-07-29 10:35                   ` Arnd Bergmann
2016-07-29 18:26                   ` Linus Torvalds

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