From: "H. Peter Anvin" <hpa@zytor.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Jan Beulich <JBeulich@suse.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Alexander van Heukelum <heukelum@fastmail.fm>,
fweisbec@gmail.com, Arjan van de Ven <arjan@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: Use -m-omit-leaf-frame-pointer to shrink text size
Date: Fri, 16 Dec 2011 07:32:09 -0800 [thread overview]
Message-ID: <4EEB6479.8010500@zytor.com> (raw)
In-Reply-To: <20111216120001.GA27801@elte.hu>
On 12/16/2011 04:00 AM, Ingo Molnar wrote:
>>
>> Are you sure about that even if the leaf function uses rBP for
>> a different purpose?
>
> Well, i assumed that GCC does not mess with %bp in leaf
> functions - a frame pointer is barely useful if it's destroyed
> spuriously in leaf functions.
>
We should verify that explicitly. gcc has every "right" to treat it as
a normal callee-saved register, but I think it is a very low priority
register in gcc's register allocation scheme.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2011-12-16 15:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-16 8:19 [PATCH] x86: Use -m-omit-leaf-frame-pointer to shrink text size Ingo Molnar
2011-12-16 8:48 ` Andrew Morton
2011-12-16 8:54 ` Ingo Molnar
2011-12-16 8:53 ` Ingo Molnar
2011-12-16 9:23 ` Jeremy Fitzhardinge
2011-12-16 10:20 ` Peter Zijlstra
2011-12-16 16:27 ` Richard Henderson
2011-12-16 11:46 ` Jan Beulich
2011-12-16 12:00 ` Ingo Molnar
2011-12-16 15:32 ` H. Peter Anvin [this message]
2011-12-16 14:01 ` Frederic Weisbecker
2011-12-16 14:06 ` Frederic Weisbecker
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