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Date: Tue, 27 Mar 2012 13:52:49 +0400
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: [JtR patch] Fast cracker for Mozilla Firefox, Thunderbird and SeaMonkey master passwords.

On Sun, Mar 25, 2012 at 11:59:11AM +0200, magnum wrote:
> I saw braces used like that in an example somewhere. I have no idea what
> they do, hence my question :)
> 
> Maybe it's better to live with the (harmless) warnings until we know for
> sure.

Strict aliasing violations are not harmless.  We may actually have wrong
code generated in some builds (where the compiler feels that it can
optimize things by taking advantage of C strict aliasing rules) - well,
hopefully the self-test will fail when that happens.

As to the warnings, not every change that makes these warnings go away
also makes the underlying issue go away.  gcc is not guaranteed to print
these warnings in every case where the source code violates C strict
aliasing rules.  It (or another compiler) may happen to generate code
other than what we intended without complaining at all.  When it does
complain, we're lucky that we're given a chance to fix the source code.

Alexander

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