From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?VG9yc3RlbiBCw7ZnZXJzaGF1c2Vu?= Subject: Re: [PATCH 4/4] transport: drop "int cmp = cmp" hack Date: Sun, 24 Mar 2013 15:54:36 +0100 Message-ID: <514F13AC.6000100@web.de> References: <20130321110338.GA18552@sigill.intra.peff.net> <20130321111333.GD18819@sigill.intra.peff.net> <20130324093212.GA28234@sigill.intra.peff.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Junio C Hamano , git@vger.kernel.org, =?UTF-8?B?VG9yc3RlbiBCw7ZnZXJzaGF1c2Vu?= To: Jeff King X-From: git-owner@vger.kernel.org Sun Mar 24 15:55:34 2013 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UJmKY-00082V-Sh for gcvg-git-2@plane.gmane.org; Sun, 24 Mar 2013 15:55:31 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753944Ab3CXOzA (ORCPT ); Sun, 24 Mar 2013 10:55:00 -0400 Received: from mout.web.de ([212.227.15.4]:60521 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753893Ab3CXOzA (ORCPT ); Sun, 24 Mar 2013 10:55:00 -0400 Received: from birne.lan ([195.67.191.23]) by smtp.web.de (mrweb101) with ESMTPA (Nemesis) id 0MNtTz-1UL8pa1Xhr-006weI; Sun, 24 Mar 2013 15:54:37 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:17.0) Gecko/20130307 Thunderbird/17.0.4 In-Reply-To: <20130324093212.GA28234@sigill.intra.peff.net> X-Provags-ID: V02:K0:XaFpE7G5e0PWjdBYznb+5OiIdfsWyHxNAAtrqPFEEGw y5TcCeQoSnkrQK+7nci29PaXly6tFwhevnvguKG5w/6RGlIkjg gDuo7P3Ly/AmUoR3sGUsHefurXKu0oh8UNX2g5z9OJTKl1VN+L AfGLpj9K4Z+I/XNf4j9FWexCB5q4bu2kzTikb/vobVIMD3X8lp U51j7hzxOuS0w55Hp0J1Q== Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On 24.03.13 10:32, Jeff King wrote: > On Sat, Mar 23, 2013 at 09:00:05PM -0700, Junio C Hamano wrote: > >> On Thu, Mar 21, 2013 at 4:13 AM, Jeff King wrote: >>> >>> According to 47ec794, this initialization is meant to >>> squelch an erroneous uninitialized variable warning from gcc >>> 4.0.1. That version is quite old at this point, and gcc 4.1 >>> and up handle it fine, with one exception. There seems to be >>> a regression in gcc 4.6.3, which produces the warning; >>> however, gcc versions 4.4.7 and 4.7.2 do not. >>> >> >> transport.c: In function 'get_refs_via_rsync': >> transport.c:127:29: error: 'cmp' may be used uninitialized in this >> function [-Werror=uninitialized] >> transport.c:109:7: note: 'cmp' was declared here >> >> gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3 > > Right, that's the same version I noted above. Is 4.6.3 the default > compiler under a particular release of Ubuntu, or did you use their > gcc-4.6 package? > > -Peff Side question: How much does it hurt to write like this: diff --git a/transport.c b/transport.c index 6b2ae94..8020b62 100644 --- a/transport.c +++ b/transport.c @@ -106,7 +106,7 @@ static void insert_packed_refs(const char *packed_refs, struct ref **list) return; for (;;) { - int cmp, len; + int cmp=0, len; ============== Using Ubuntu 10.4, using gcc (Ubuntu 4.4.3-4ubuntu5.1) 4.4.3 the compiler will add a line like this: 2e83: 31 ff xor %edi,%edi (Which should not be to slow to execute) Looking at a later gcc, from upcoming Debian, with gcc (Debian 4.7.2-5) 4.7.2 the assembly code is exactly the same ;-)