Message-ID: <46CC9696.1070107@oracle.com>
Date: Wed, 22 Aug 2007 13:03:34 -0700
From: Randy Dunlap <randy.dunlap@oracle.com>
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To: Andi Kleen <ak@suse.de>
CC: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
       Jan Beulich <jbeulich@novell.com>
Subject: Re: 2.6.23-rc3-mm1
References: <20070822020648.5ea3a612.akpm@linux-foundation.org> <20070822110348.8fd6a937.randy.dunlap@oracle.com> <20070822113211.9ac85162.akpm@linux-foundation.org> <20070822193857.GC8058@bingen.suse.de> <20070822121731.011cd263.randy.dunlap@oracle.com> <20070822205311.GH8058@bingen.suse.de>
In-Reply-To: <20070822205311.GH8058@bingen.suse.de>
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Andi Kleen wrote:
> On Wed, Aug 22, 2007 at 12:17:31PM -0700, Randy Dunlap wrote:
>>> Why does that compiler not know __builtin_abs?
>> I dunno:
>>
>>> gcc --version
>> gcc (GCC) 4.1.0 (SUSE Linux)
> 
> Hmm I use the same compiler from SUSE10.2 and it works for me (with both
> mm and only my tree applied) 
> 
> Ok mm fails with some errors in the wireless drivers but with 
> wireless disabled it compiles.
> 
> When you compile a simple test program like
> 
> main() { printf("%lu\n", __builtin_labs(-1)); }
> 
> does it work?

Yes, that works.

>>>> One wonders why x86_64-mm-unwinder.patch has an open-coded call to
>>>> __builtin_labs(), when include/linux/kernel.h:abs() should do a fine job.
> 
> Andrew, I actually checked that and the abs() there is just abs()
> not a labs(). So it wouldn't work on 64bit platform.
> 
> We could opencode it of course, but __builtin_labs should be really 
> there.
> 
> -Andi


-- 
~Randy
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