Date: Wed, 22 Aug 2007 22:53:11 +0200
From: Andi Kleen <ak@suse.de>
To: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Andi Kleen <ak@suse.de>, Andrew Morton <akpm@linux-foundation.org>,
       linux-kernel@vger.kernel.org, Jan Beulich <jbeulich@novell.com>
Subject: Re: 2.6.23-rc3-mm1
Message-ID: <20070822205311.GH8058@bingen.suse.de>
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>
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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?


> > > 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
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