linux-kernel - Re: Question on compiler warning

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Message-ID: <52C31AE4.1050501@lwfinger.net>
Date:	Tue, 31 Dec 2013 13:28:36 -0600
From:	Larry Finger <Larry.Finger@...inger.net>
To:	Mark Cave-Ayland <mark.cave-ayland@...nde.co.uk>
CC:	linux-wireless <linux-wireless@...r.kernel.org>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: Question on compiler warning

On 12/31/2013 04:56 AM, Mark Cave-Ayland wrote:
> Hi Larry,
>
> Could it be that you don't see the issue the locally because you've got
> different compiler optimisation settings? I've seen a similar bug recently on
> another project where the "may be used uninitialized" warning appears with -O0
> and -O1 but magically disappears with the default -O2 setting (presumably
> because the optimiser performs some kind of inlining/reordering that makes the
> issue go away).

Mark,

It is possible. Certainly, a higher optimization level will force the compiler 
to do a better job of flow analysis. I am using -O2, which is the standard in 
the kernel makefile. I would expect that Geert is also using the same lever, but 
perhaps not.

Larry


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