Re: 2.6.23-rc3-mm1

From: Andi Kleen
Date: Wed Aug 22 2007 - 15:59:37 EST


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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/