From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261250AbUBZXBO (ORCPT ); Thu, 26 Feb 2004 18:01:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261248AbUBZW6j (ORCPT ); Thu, 26 Feb 2004 17:58:39 -0500 Received: from mx1.redhat.com ([66.187.233.31]:12182 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S261231AbUBZW5k (ORCPT ); Thu, 26 Feb 2004 17:57:40 -0500 To: Linus Torvalds Cc: Kernel Mailing List , Andrew Morton , arjanv@redhat.com, davej@redhat.com, Ingo Molnar Subject: Re: raid 5 with >= 5 members broken on x86 References: From: Alexandre Oliva Organization: Red Hat Global Engineering Services Compiler Team Date: 26 Feb 2004 19:57:31 -0300 In-Reply-To: Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Feb 26, 2004, Linus Torvalds wrote: > Ok. I did the silly one-liner, but if the "don't care" approach really > improves code generation, feel free to send one that fixes both the P5 and > PII cases.. FWIW, I think the silly one-liner is actually an improvement, since then we use a hardware register for the counter, instead of a stack location. I was concerned about not increasing the register pressure with the patch; it looked very tight already, and I couldn't tell it wouldn't be exceeded with some older compiler that failed to eliminate the frame pointer, for example. If that's the way to go, I'll post a patch that leaves the +r alone. If using a stack location for the counter could possibly be as efficient as using a register, I'd convert "+r" (lines) to "+g". Any preferences? -- Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/ Happy GNU Year! oliva@{lsd.ic.unicamp.br, gnu.org} Red Hat GCC Developer aoliva@{redhat.com, gcc.gnu.org} Free Software Evangelist Professional serial bug killer