From: Øyvind A. Holm <sunny@sunbase.org>
Date: Fri, 25 May 2012 15:18:00 GMT
Subject: Re: [PATCH 3/3] xdiff: import new 32-bit version of count_masked_bytes()
Message-ID: <CAA787rkRZudv96wJ4WPFWt7k0Y628dvhxrPes1g6rbw8C_Kiog@mail.gmail.com>
In-Reply-To: <4FBBF8E9.7020103@lsrfire.ath.cx>

On 22 May 2012 22:36, René Scharfe <rene.scharfe@lsrfire.ath.cx> wrote:
> Import the latest 32-bit implementation of count_masked_bytes() from
> Linux (arch/x86/include/asm/word-at-a-time.h).  It's shorter and avoids
> overflows and negative numbers.
>
> This fixes test failures on 32-bit, where negative partial results had
> been shifted right using the "wrong" method (logical shift right instead
> of arithmetic short right).  The compiler is free to chose the method,
> so it was only wrong in the sense that it didn't work as intended by us.
>
> Reported-by: Øyvind A. Holm <sunny@sunbase.org>
> Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
> ---
> Does this fix all the warnings, and do the tests pass?  I can only
> reproduce the "shifting to far to the right" warning..

Hi, I finally got around to test this, and it compiles flawlessly with
your three patches. No warnings, and the test suite seems to run
without errors.

Nice work, sir.

Cheers,
Øyvind