linux-kernel - Re: [PATCH] regmap: silence GCC warning

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Date:	Mon, 01 Oct 2012 12:16:46 +0200
From:	Paul Bolle <pebolle@...cali.nl>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] regmap: silence GCC warning

On Mon, 2012-10-01 at 11:03 +0100, Mark Brown wrote:
> On Sun, Sep 30, 2012 at 12:15:55PM +0200, Paul Bolle wrote:
> > Building regmap.o triggers this GCC warning:
> >     drivers/base/regmap/regmap.c: In function ‘regmap_raw_read’:
> >     drivers/base/regmap/regmap.c:1172:6: warning: ‘ret’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> > 
> > It seems 'ret' should always be set when this function returns. See, the
> > else-branch can leave 'ret' uninitialized only if 'val_count' is zero.
> > But if 'val_count' is zero regmap_volatile_range() will return true.
> > That implies that 'ret' will be set in the if-branch. ('val_count' could
> > be zero if 'val_len' is, for example, zero. That would be useless input,
> > however.)
> > 
> > Anyhow, initializing 'ret' to -EINVAL silences GCC and is harmless.
> 
> Have you reported this bug in GCC?

No I haven't. Since you ask, I guess you too think 'ret' is always set
when this function returns, don't you? Ie, my analysis isn't obviously
wrong.

> Their flow analyis just seems to keep on getting worse and worse.


Paul Bolle

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