From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 62507 invoked by alias); 20 Nov 2015 16:41:00 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 62476 invoked by uid 89); 20 Nov 2015 16:40:59 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 X-Spam-User: qpsmtpd, 3 recipients X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Fri, 20 Nov 2015 16:40:58 +0000 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (Postfix) with ESMTPS id 572348F50B; Fri, 20 Nov 2015 16:40:57 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-91.phx2.redhat.com [10.3.113.91]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id tAKGeueV020546; Fri, 20 Nov 2015 11:40:56 -0500 Subject: Re: basic asm and memory clobbers To: Andrew Haley , David Wohlferd , Segher Boessenkool References: <563FE459.3000003@LimeGreenSocks.com> <20151109093229.GA5260@gate.crashing.org> <56493010.9070707@LimeGreenSocks.com> <564A4AA5.1080706@redhat.com> <564AC155.4040601@LimeGreenSocks.com> <564B9CB1.1060001@redhat.com> <564E762B.6070705@LimeGreenSocks.com> <564EF338.4030703@redhat.com> <564EF7FF.1070107@LimeGreenSocks.com> <564F008B.8040703@redhat.com> Cc: "gcc@gcc.gnu.org" , rth@gcc.gnu.org, pinskia@gcc.gnu.org, Sandra Loosemore From: Jeff Law Message-ID: <564F4D18.5010302@redhat.com> Date: Fri, 20 Nov 2015 16:41:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <564F008B.8040703@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2015-11/txt/msg00130.txt.bz2 On 11/20/2015 04:14 AM, Andrew Haley wrote: > On 20/11/15 10:37, David Wohlferd wrote: >> The intent for 24414 is to change basic asm such that it will become >> (quoting jeff) "an opaque blob that read/write/clobber any register or >> memory location." Such being the case, "memory" is not sufficient: >> >> #define CLOBBERALL "eax", "ebx", "ecx", "edx", "r8", "r9", "r10", "r11", >> "r12", "r13", "r14", "r15", "edi", "esi", "ebp", "cc", "memory" > > Hmm. I would not be at all surprised to see this cause reload > failures. You certainly shouldn't clobber the frame pointer on > any machine which needs one. Right. It'll cause other issues as well. It's the only reason why I didn't change the code internally to stomp every hard register back in 1999. jeff