From owner-freebsd-hackers@FreeBSD.ORG Sat Dec 23 01:19:43 2006 Return-Path: X-Original-To: freebsd-hackers@FreeBSD.ORG Delivered-To: freebsd-hackers@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 89DF316A415 for ; Sat, 23 Dec 2006 01:19:43 +0000 (UTC) (envelope-from gemini@geminix.org) Received: from geminix.org (geminix.org [213.73.82.81]) by mx1.freebsd.org (Postfix) with ESMTP id 5194613C425 for ; Sat, 23 Dec 2006 01:19:43 +0000 (UTC) (envelope-from gemini@geminix.org) Message-ID: <458C7DC4.1080304@geminix.org> Date: Sat, 23 Dec 2006 01:52:20 +0100 From: Uwe Doering Organization: Private UNIX Site User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.8.0.9) Gecko/20061220 SeaMonkey/1.0.7 MIME-Version: 1.0 To: Garrett Cooper References: <200612220850.kBM8oDD0037287@lurza.secnetix.de> <458C1BCB.6040907@u.washington.edu> In-Reply-To: <458C1BCB.6040907@u.washington.edu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Received: from gemini by geminix.org with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.63 (FreeBSD)) (envelope-from ) id 1Gxv7d-000JtG-0G; Sat, 23 Dec 2006 02:19:42 +0100 Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Properly controlling CFLAGS/CXXFLAGS X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 23 Dec 2006 01:19:43 -0000 Garrett Cooper wrote: >> [...] > Interesting. No wonder I didn't have it in my Gentoo /etc/make.conf. It > appears (from what I see) that maybe -fno-strict-aliasing has been > enabled by default (at least it doesn't show up in the GCC 4.1.1 manpage > on FC5). It's documented in GCC's info page. There, you may want to search for '-fstrict-aliasing' instead of '-fno-strict-aliasing'. The 'no-' prefix is generic and can be used to switch off flags that are on by default or have been set to on earlier in the command line. With '-O2' and better, '-fstrict-aliasing' is the default in newer versions of GCC, AFAIK, but people tend to switch it off because it apparently breaks too many software packages. Or at least those whose code base dates back to times where '-fno-strict-aliasing' was the default and people got away with certain nasty coding hacks that no longer work with '-fstrict-aliasing'. Uwe -- Uwe Doering | EscapeBox - Managed On-Demand UNIX Servers gemini@geminix.org | http://www.escapebox.net