Re: [PATCH] Avoid gcc compiler warning

From: Jeff King <peff@peff.net>
Date: Dec 9, 2014, 08:47 UTC
Message-ID: <20141209084728.GA13123@peff.net>
In-Reply-To: <b9e1cb1f858e71b964be4f752fcebc22cd944ebc.1418056722.git.johannes.schindelin@gmx.de>

On Mon, Dec 08, 2014 at 05:38:59PM +0100, Johannes Schindelin wrote:

Show 8 quoted lines

> At least on this developer's MacOSX (Snow Leopard, gcc-4.2.1), GCC prints
> a warning that 'hash' may be used uninitialized when compiling
> test-hashmap that 'hash' may be used uninitialized (but GCC 4.6.3 on this
> developer's Ubuntu server does not report this problem).
> 
> Since hash() is called from perf_hashmap() which accepts an unchecked
> integer value from the command line, the warning appears to be legitimate,
> even if the test-hashmap command is only called from the test suite.

I think the older gcc is wrong; we are switching on "method & 3", which must be in the range 0-3 (and we cover all cases).

I do not mind silencing the warning anyway, but see this discussion:

  http://thread.gmane.org/gmane.comp.version-control.git/258186

The thread seems very broken in gmane, but it continues here:

  http://article.gmane.org/gmane.comp.version-control.git/258232

  http://thread.gmane.org/gmane.comp.version-control.git/258245

  http://article.gmane.org/gmane.comp.version-control.git/258264

-Peff