From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 36117 invoked by alias); 22 Sep 2015 19:18:21 -0000 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 Received: (qmail 36046 invoked by uid 89); 22 Sep 2015 19:18:21 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.3 required=5.0 tests=AWL,BAYES_20,KAM_LAZY_DOMAIN_SECURITY,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=no version=3.3.2 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; Tue, 22 Sep 2015 19:18:19 +0000 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (Postfix) with ESMTPS id 4CEC78C1BC; Tue, 22 Sep 2015 19:18:17 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-92.phx2.redhat.com [10.3.113.92]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t8MJIGm6020888; Tue, 22 Sep 2015 15:18:16 -0400 Subject: Re: [PATCH] Explicit register earlyclobber fix To: Richard Henderson , Andrew Jenner , GCC Patches References: <56017AA6.20709@codesourcery.com> <5601A2DD.5090408@redhat.com> <5601A82C.7060307@redhat.com> <5601A8EF.4050803@redhat.com> From: Jeff Law Message-ID: <5601A978.9040107@redhat.com> Date: Tue, 22 Sep 2015 19:31:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <5601A8EF.4050803@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2015-09/txt/msg01687.txt.bz2 On 09/22/2015 01:15 PM, Richard Henderson wrote: >> And doesn't it have to be =& and always at the start for an asm constraint? >> For operands in patterns, we have to consider operand alternatives, but that's >> not on issue here. > > Technically we do support alternatives on asms. Not usefully except for CISC, > since all alternatives have to use the same output pattern, but one can write > things like > > asm("add %0,%1" : "=r,m"(x) : "rim,ri"(y)) Wow, learn something every day. In that case, I think we do have to search a little harder than just peeking at the first two letters of the constraint :( jeff