From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 124868 invoked by alias); 9 Mar 2015 17:40:53 -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 124859 invoked by uid 89); 9 Mar 2015 17:40:52 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.8 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham 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; Mon, 09 Mar 2015 17:40:52 +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 (8.14.4/8.14.4) with ESMTP id t29HejIj020981 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 9 Mar 2015 13:40:46 -0400 Received: from [10.3.113.56] (ovpn-113-56.phx2.redhat.com [10.3.113.56]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t29HeiwM010227; Mon, 9 Mar 2015 13:40:44 -0400 Message-ID: <54FDDB1C.2000006@redhat.com> Date: Mon, 09 Mar 2015 17:40:00 -0000 From: Jeff Law User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Steven Bosscher , Alex Velenko CC: GCC Patches , Marcus Shawcroft Subject: Re: [PATCH] [RTL] Relax CSE check to set REG_EQUAL notes. References: <1425467354-6018-1-git-send-email-alex.velenko@arm.com> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2015-03/txt/msg00485.txt.bz2 On 03/09/15 03:53, Steven Bosscher wrote: > On Wed, Mar 4, 2015 at 12:09 PM, Alex Velenko wrote: >> For example, in arm testcase pr43920-2.c, CSE previously decided not to put >> an "obvious" note on insn 9, as set value was the same as note value. >> At the same time, other insns set up as -1 were set up through a register >> and did get a note: > > ...which is the point of the REG_EQUAL notes. In insn 8 there is a > REG_EQUAL note to show that the value of r111 is known. In insn 9 the > known value is, well, known from SET_SRC so there is no need for a > REG_EQUAL note. Adding REG_EQUAL notes in such cases is just wasteful. RIght. I'd rather look into why later passes aren't discovering whatever equivalences are important rather than adding the redundant notes. Regardless, I think this is a gcc-6 issue, so I'm not likely to look at it in the immediate future. jeff