Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S272575AbTHKNUb (ORCPT ); Mon, 11 Aug 2003 09:20:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S272577AbTHKNUb (ORCPT ); Mon, 11 Aug 2003 09:20:31 -0400 Received: from sccrmhc13.comcast.net ([204.127.202.64]:20651 "EHLO sccrmhc13.comcast.net") by vger.kernel.org with ESMTP id S272575AbTHKNU3 (ORCPT ); Mon, 11 Aug 2003 09:20:29 -0400 Subject: Re: [PATCH] 2.4.22pre10: {,un}likely_p() macros for pointers From: Albert Cahalan To: Jamie Lokier Cc: Andrew Morton , akpm@osdl.org, Willy Tarreau , Chip Salzenberg , Albert Cahalan , linux-kernel mailing list , davem@redhat.com In-Reply-To: <20030811054209.GN10446@mail.jlokier.co.uk> References: <1060488233.780.65.camel@cube> <20030810072945.GA14038@alpha.home.local> <20030811012337.GI24349@perlsupport.com> <20030811020957.GE10446@mail.jlokier.co.uk> <20030811023912.GJ24349@perlsupport.com> <20030811053059.GB28640@alpha.home.local> <20030811054209.GN10446@mail.jlokier.co.uk> Content-Type: text/plain Organization: Message-Id: <1060607398.948.213.camel@cube> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.4 Date: 11 Aug 2003 09:09:59 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1272 Lines: 37 On Mon, 2003-08-11 at 01:42, Jamie Lokier wrote: > Willy Tarreau wrote: > > So in any case, the !!(x) construct should be valid. > > Yes, either of these is fine for pointers and integers alike: > > #define likely(x) __builtin_expect ((x) != 0, 1) > #define unlikely(x) __builtin_expect ((x) != 0, 0) > > #define likely(x) __builtin_expect (!!(x), 1) > #define unlikely(x) __builtin_expect (!!(x), 0) Choosing the more familiar idiom for booleanizing a value, here we go: diff -Naurd old/include/linux/compiler.h new/include/linux/compiler.h --- old/include/linux/compiler.h 2003-08-11 09:02:18.000000000 -0400 +++ new/include/linux/compiler.h 2003-08-11 09:04:58.000000000 -0400 @@ -24,8 +24,8 @@ #define __builtin_expect(x, expected_value) (x) #endif -#define likely(x) __builtin_expect((x),1) -#define unlikely(x) __builtin_expect((x),0) +#define likely(x) __builtin_expect(!!(x),1) +#define unlikely(x) __builtin_expect(!!(x),0) /* * Allow us to mark functions as 'deprecated' and have gcc emit a nice - 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/