From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31526 invoked by alias); 21 Jun 2010 14:17:19 -0000 Received: (qmail 31509 invoked by uid 22791); 21 Jun 2010 14:17:18 -0000 X-SWARE-Spam-Status: No, hits=-1.8 required=5.0 tests=AWL,BAYES_00,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (38.113.113.100) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 21 Jun 2010 14:17:13 +0000 Received: (qmail 21809 invoked from network); 21 Jun 2010 14:17:11 -0000 Received: from unknown (HELO ?192.168.44.101?) (nathan@127.0.0.2) by mail.codesourcery.com with ESMTPA; 21 Jun 2010 14:17:11 -0000 Message-ID: <4C1F7437.90304@codesourcery.com> Date: Mon, 21 Jun 2010 14:50:00 -0000 From: Nathan Sidwell User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.9) Gecko/20100423 Thunderbird/3.0.4 MIME-Version: 1.0 To: Michael Matz CC: IainS , Richard Guenther , GCC Patches Subject: Re: [gimple] assignments to volatile References: <4C1F5380.1090107@codesourcery.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2010-06/txt/msg02035.txt.bz2 On 06/21/10 15:09, Michael Matz wrote: > Yes, namely that the author explicitely wrote a read access to vobj. > To demonstrate, like > return vobj; > implies a read from vobj, also > return vobj = x; > implies a read from vobj. The latter _also_ implies a store to vobj. If > you want the read to not happen the author better writes > vobj = x; > return x; Then what about plain vobj; ? Is that a read of vobj? what about hiding the assignment inside a cond expr cond ? vobj = expr : 0; Is that a re-read of vobj? nathan -- Nathan Sidwell :: http://www.codesourcery.com :: CodeSourcery