From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1493 invoked by alias); 28 Jun 2018 23:48:51 -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 1331 invoked by uid 89); 28 Jun 2018 23:48:33 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-10.9 required=5.0 tests=BAYES_00,GIT_PATCH_2,GIT_PATCH_3,KAM_LAZY_DOMAIN_SECURITY,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy= 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 ESMTP; Thu, 28 Jun 2018 23:48:31 +0000 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 679C9804E4; Thu, 28 Jun 2018 23:48:30 +0000 (UTC) Received: from localhost.localdomain (ovpn-112-5.rdu2.redhat.com [10.10.112.5]) by smtp.corp.redhat.com (Postfix) with ESMTP id A28328247E; Thu, 28 Jun 2018 23:48:28 +0000 (UTC) Subject: Re: [patch, i386] false dependencies fix To: Uros Bizjak , "gcc-patches@gcc.gnu.org" Cc: "Nesterovskiy, Alexander" References: From: Jeff Law Openpgp: preference=signencrypt Message-ID: Date: Fri, 29 Jun 2018 00:04:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2018-06/txt/msg01845.txt.bz2 On 06/28/2018 01:16 AM, Uros Bizjak wrote: > Hello! > >>> --- i386.md (revision 259756) >>> +++ i386.md (working copy) >>> @@ -3547,7 +3547,7 @@ >>> { >>> case MODE_DF: >>> if (TARGET_AVX && REG_P (operands[0]) && REG_P (operands[1])) >>> - return "vmovsd\t{%1, %0, %0|%0, %0, %1}"; >>> + return "%vmovsd\t{%d1, %0|%0, %d1}"; >>> return "%vmovsd\t{%1, %0|%0, %1}"; >>> >>> case MODE_V4SF: >>> @@ -3748,7 +3748,7 @@ >>> { >>> case MODE_SF: >>> if (TARGET_AVX && REG_P (operands[0]) && REG_P (operands[1])) >>> - return "vmovss\t{%1, %0, %0|%0, %0, %1}"; >>> + return "%vmovss\t{%d1, %0|%0, %d1}"; >>> return "%vmovss\t{%1, %0|%0, %1}"; >> So what I'm confused about is in the original output template operand 0 >> is duplicated. In the new template operand 1 is duplicated. >> >> Presumably what you're trying to accomplish is avoiding a false read on >> operand 0 (the destination)? Can you please confirm? > >> Knowing that should also help me evaluate the changes to recp and rsqrt >> since they're being changed to the same style encoding when operating >> strictly on registers. > > Please don't change "v" -> "%v" for TARGET_AVX templates. We know that > in this case, all insn mnemonics are prefixed with "v". I didn't realize you'd already acked the patch without the v->%v bits and Sebastian committed the changes about a month ago... Oh well, at least I know a bit more about the inner workings of the AVX unit than I did a last week. Sorry for the noise. jeff