From owner-freebsd-current@FreeBSD.ORG Wed Feb 18 06:51:12 2009 Return-Path: Delivered-To: current@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 48E381065676; Wed, 18 Feb 2009 06:51:12 +0000 (UTC) (envelope-from xcllnt@mac.com) Received: from asmtpout015.mac.com (asmtpout015.mac.com [17.148.16.90]) by mx1.freebsd.org (Postfix) with ESMTP id 30B858FC22; Wed, 18 Feb 2009 06:51:12 +0000 (UTC) (envelope-from xcllnt@mac.com) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=US-ASCII; format=flowed Received: from MacBook-Pro.lan.xcllnt.net (xcllnt.net [75.101.29.67]) by asmtp015.mac.com (Sun Java(tm) System Messaging Server 6.3-7.03 (built Aug 7 2008; 32bit)) with ESMTPSA id <0KF900CBA1PAMW60@asmtp015.mac.com>; Tue, 17 Feb 2009 22:51:12 -0800 (PST) Message-id: From: Marcel Moolenaar To: "M. Warner Losh" In-reply-to: <20090217.234216.1276682135.imp@bsdimp.com> Date: Tue, 17 Feb 2009 22:51:10 -0800 References: <20090217.203647.-1518647466.imp@bsdimp.com> <20090217.222152.-109416210.imp@bsdimp.com> <4CB77F1D-4235-47D8-B654-1C4F29B6C649@mac.com> <20090217.234216.1276682135.imp@bsdimp.com> X-Mailer: Apple Mail (2.930.3) Cc: mips@FreeBSD.org, tinderbox@FreeBSD.org, current@FreeBSD.org Subject: Re: [head tinderbox] failure on mips/mips X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 18 Feb 2009 06:51:13 -0000 On Feb 17, 2009, at 10:42 PM, M. Warner Losh wrote: > : A safer approach is to mark ifi_epoch as packed or put differently, > : define time_t as a 64-bit integral with 32-bit alignment. This can > : avoid a lot of unexpected internal padding as well (e.g. struct > : timeval). > > Marking it as packed won't help. If the elements aren't properly > aligned, gcc won't access multi-word entities properly. It might > eliminate the warning, but it will break at runtime. But GCC will use a pair of 32-bit loads and/or stores to access the 64-bit integral in that case. There should be no runtime breakage. You only do this for n32 of course. -- Marcel Moolenaar xcllnt@mac.com