Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752291AbZA1Tlt (ORCPT ); Wed, 28 Jan 2009 14:41:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751120AbZA1Tli (ORCPT ); Wed, 28 Jan 2009 14:41:38 -0500 Received: from x35.xmailserver.org ([64.71.152.41]:52516 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751049AbZA1Tli (ORCPT ); Wed, 28 Jan 2009 14:41:38 -0500 X-AuthUser: davidel@xmailserver.org Date: Wed, 28 Jan 2009 11:41:16 -0800 (PST) From: Davide Libenzi X-X-Sender: davide@alien.or.mcafeemobile.com To: Chris Snook cc: Linux Kernel Mailing List Subject: Re: if (unlikely(...)) == unnecessary? In-Reply-To: <49809C2E.3000005@redhat.com> Message-ID: References: <49809C2E.3000005@redhat.com> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) X-GPG-FINGRPRINT: CFAE 5BEE FD36 F65E E640 56FE 0974 BF23 270F 474E X-GPG-PUBLIC_KEY: http://www.xmailserver.org/davidel.asc MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 760 Lines: 22 On Wed, 28 Jan 2009, Chris Snook wrote: > Davide Libenzi wrote: > > I noticed that GCC >= 3.3 (not tried the ones before) automatically branches > > out the "if" code (and follow-through the "else" code, if there). Is that a > > coincidence or a rule we can rely on going forward? > > That's the default behavior, but there are lots of things that can cause it to > behave differently. Please don't keep me hanging. What are they (just a few of the "lots" that makes GCC follow-through "if" code)? - Davide -- 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/