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Date: Mon, 14 Sep 2009 14:36:15 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-kernel@vger.kernel.org, sam@ravnborg.org
Subject: Re: [PATCH] [5/5] kbuild: Set -fconserve-stack option for gcc 4.5
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On Mon, 14 Sep 2009 22:18:11 +0200 (CEST)
Andi Kleen <andi@firstfloor.org> wrote:

> 
> The upcomming gcc 4.5 has a new -fconserve-stack option 
> that tells the inliner to take stack frame size in account.
> Set it if the compiler supports it.
> 
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> 
> ---
>  Makefile |    3 +++
>  1 file changed, 3 insertions(+)
> 
> Index: linux-2.6.31-rc3-ak/Makefile
> ===================================================================
> --- linux-2.6.31-rc3-ak.orig/Makefile
> +++ linux-2.6.31-rc3-ak/Makefile
> @@ -575,6 +575,9 @@ KBUILD_CFLAGS	+= $(call cc-option,-fno-s
>  # revert to pre-gcc-4.4 behaviour of .eh_frame
>  KBUILD_CFLAGS	+= $(call cc-option,-fno-dwarf2-cfi-asm)
>  
> +# conserve stack if available
> +KBUILD_CFLAGS   += $(call cc-option,-fconserve-stack)

Do we have any info about what effects this option has upon the
generated code?  Text size changes, runtime stack usage changes, etc?