Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757481AbZKSQTh (ORCPT ); Thu, 19 Nov 2009 11:19:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757292AbZKSQTf (ORCPT ); Thu, 19 Nov 2009 11:19:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:15618 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756651AbZKSQTd (ORCPT ); Thu, 19 Nov 2009 11:19:33 -0500 Message-ID: <4B056FAD.2080500@redhat.com> Date: Thu, 19 Nov 2009 16:17:49 +0000 From: Andrew Haley User-Agent: Thunderbird 2.0.0.23 (X11/20090825) MIME-Version: 1.0 To: Thomas Gleixner CC: Ingo Molnar , "H. Peter Anvin" , LKML , Andrew Morton , Heiko Carstens , feng.tang@intel.com, Fr??d??ric Weisbecker , Steven Rostedt , Peter Zijlstra , jakub@redhat.com, gcc@gcc.gnu.org Subject: Re: BUG: GCC-4.4.x changes the function frame on some functions References: <20091119072040.GA23579@elte.hu> <4B0567E0.5080803@redhat.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 805 Lines: 22 Thomas Gleixner wrote: > On Thu, 19 Nov 2009, Andrew Haley wrote: >> Thomas Gleixner wrote: >>> There is no real obvious reason why the edi magic needs to be done >>> _before_ >>> >>> push %ebp >>> mov %esp,%ebp >> Sure there is: unless you do the adjustment first %ebp won't be 16-aligned. > > And why is this not done in 99% of the functions in the kernel, just > in this one and some random others ? If I could see the function I might be able to tell you. It's either a performance enhancement, something to do with SSE, or it's a bug. Andrew. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/