From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 78860 invoked by alias); 2 May 2016 13:32:07 -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 78792 invoked by uid 89); 2 May 2016 13:32:02 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.9 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=utilizes 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, 02 May 2016 13:32:01 +0000 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A81493E5; Mon, 2 May 2016 13:31:59 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-69.phx2.redhat.com [10.3.113.69]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u42DVw9e021132; Mon, 2 May 2016 09:31:59 -0400 Subject: Re: Enabling -frename-registers? To: Bernd Schmidt , David Edelsohn , GCC Patches References: <57236285.5090908@redhat.com> Cc: Segher Boessenkool From: Jeff Law Message-ID: <8fcd1d5f-7e42-a50e-e530-b0ba93166daf@redhat.com> Date: Mon, 02 May 2016 13:32:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.0 MIME-Version: 1.0 In-Reply-To: <57236285.5090908@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2016-05/txt/msg00093.txt.bz2 On 04/29/2016 07:32 AM, Bernd Schmidt wrote: > On 04/29/2016 03:02 PM, David Edelsohn wrote: >> How has this show general benefit for all architectures to deserve >> enabling it by default at -O2? > > It should improve postreload scheduling in general, and it can also help > clear up bad code generation left behind by register allocation. Right. ISTM the round-robin renaming reduces the false dependencies that are inherently created by register allocation. It should benefit any architecture that utilizes post-reload scheduling. jeff