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Date: Sat, 18 Jul 2009 14:01:45 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Anton Vorontsov <avorontsov@ru.mvista.com>, Sam Ravnborg <sam@ravnborg.org>
Subject: Re: [PATCH RFC 1/2] Makefile: Never use -fno-omit-frame-pointer
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* Anton Vorontsov <avorontsov@ru.mvista.com> wrote:

> On Wed, Jun 17, 2009 at 12:16:30AM +0400, Anton Vorontsov wrote:
> > According to Segher Boessenkool and GCC manual, -fomit-frame-pointer
> > is only the default when optimising on archs/ABIs where it doesn't
> > hinder debugging and -pg. So, we do not get it by default on x86,
> > not at any optimisation level.
> > 
> > On the other hand, *using* -fno-omit-frame-pointer causes gcc to
> > produce buggy code on PowerPC targets.
> > 
> > If Segher and GCC manual are right, this patch should be a no-op
> > for all arches except PowerPC, where the patch fixes gcc issues.
> > 
> > Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
> > ---
> > 
> > See this thread for more discussion:
> > http://osdir.com/ml/linux-kernel/2009-05/msg01754.html
> > 
> > p.s.
> > Obviously, I didn't test this patch on anything else but PPC32. ;-)
> > 
> > Segher, do you know if all GCC versions that we support for
> > building Linux are behaving the way that GCC manual describe?
> 
> No news is good news... Ingo, can we merge this into -tip for 
> testing?

Changes to the top level Makefile should really go via Sam's kbuild 
tree.

	Ingo