From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17888 invoked by alias); 14 Jul 2011 16:43:20 -0000 Received: (qmail 17878 invoked by uid 22791); 14 Jul 2011 16:43:19 -0000 X-SWARE-Spam-Status: No, hits=-1.8 required=5.0 tests=AWL,BAYES_00,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; Thu, 14 Jul 2011 16:43:04 +0000 Received: (qmail 7205 invoked from network); 14 Jul 2011 16:43:03 -0000 Received: from unknown (HELO ?84.152.205.52?) (bernds@127.0.0.2) by mail.codesourcery.com with ESMTPA; 14 Jul 2011 16:43:03 -0000 Message-ID: <4E1F1C94.8070805@codesourcery.com> Date: Thu, 14 Jul 2011 16:48:00 -0000 From: Bernd Schmidt User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.17) Gecko/20110708 Lightning/1.0b3pre Thunderbird/3.1.10 MIME-Version: 1.0 To: Richard Henderson CC: GCC Patches , Eric Botcazou , Steve Ellcey , "Vladimir N. Makarov" Subject: Re: Correct fix for scheduler bug PR11320 References: <4E1EBEFE.3080002@codesourcery.com> <4E1F135C.8080705@redhat.com> <4E1F1718.6000302@codesourcery.com> <4E1F1BC1.4090607@redhat.com> In-Reply-To: <4E1F1BC1.4090607@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 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: 2011-07/txt/msg01187.txt.bz2 On 07/14/11 18:39, Richard Henderson wrote: > On 07/14/2011 09:19 AM, Bernd Schmidt wrote: >> Yes, but not using the fixed got pointer in r1, but a random other >> register which can have different values in the function. > > Oh, I think I see. > > So if this really had been a PLUS, as implied by the LO_SUM, > we would have had garbage input, produced garbage output, but > (eventually) ignored the result. > > But since this really is a load from memory, the garbage > input is immediately fatal. > > Have I got that right? This is correct. > If so, the patch with the use of gen_const_mem is ok. Will commit. (Although now I wonder if we could instead use one of the speculative load instructions? There's one that sets the NaT bit if the load would fault, isn't there? It's been so long I can't remember.) > It does raise the question of whether we ought to completely > change the way we represent the pairing of LTOFFX/LDXMOV > relocations. This I can't answer since I don't know the definition of these. Bernd