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Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1

From Markus Trippelsdorf <markus@trippelsdorf.de>
Newsgroups linux.kernel
Subject Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1
Date 2016-07-28 20:10 +0200
Message-ID <rZXUR-1l2-7@gated-at.bofh.it> (permalink)
References (2 earlier) <nwGBA-4bA-25@gated-at.bofh.it> <nBeOl-7wr-1@gated-at.bofh.it> <rZL7k-14A-23@gated-at.bofh.it> <rZORz-3Ef-9@gated-at.bofh.it> <rZPaW-3LV-11@gated-at.bofh.it>
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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

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Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Borislav Petkov <bp@alien8.de> - 2016-07-28 06:30 +0200
  Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Ingo Molnar <mingo@kernel.org> - 2016-07-28 10:30 +0200
    Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Borislav Petkov <bp@alien8.de> - 2016-07-28 10:50 +0200
      Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Ingo Molnar <mingo@kernel.org> - 2016-07-28 19:00 +0200
        Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Ingo Molnar <mingo@kernel.org> - 2016-07-28 19:10 +0200
      Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Markus Trippelsdorf <markus@trippelsdorf.de> - 2016-07-28 20:10 +0200
    Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Linus Torvalds <torvalds@linux-foundation.org> - 2016-07-28 21:10 +0200
      Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Linus Torvalds <torvalds@linux-foundation.org> - 2016-07-28 21:10 +0200
        Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Ingo Molnar <mingo@kernel.org> - 2016-07-28 22:30 +0200
      Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Linus Torvalds <torvalds@linux-foundation.org> - 2016-07-28 23:30 +0200
        Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Borislav Petkov <bp@alien8.de> - 2016-07-29 12:20 +0200
          Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Arnd Bergmann <arnd@arndb.de> - 2016-07-29 12:40 +0200
          Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Linus Torvalds <torvalds@linux-foundation.org> - 2016-07-29 20:30 +0200
        Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1 Arnd Bergmann <arnd@arndb.de> - 2016-07-29 12:20 +0200

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