From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 83018 invoked by alias); 14 Oct 2015 12:42:24 -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 83007 invoked by uid 89); 14 Oct 2015 12:42:23 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.7 required=5.0 tests=AWL,BAYES_00,SPF_HELO_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; Wed, 14 Oct 2015 12:42:22 +0000 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id BDFED226; Wed, 14 Oct 2015 12:42:21 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-105.phx2.redhat.com [10.3.113.105]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t9ECgLrU007159; Wed, 14 Oct 2015 08:42:21 -0400 Subject: Re: [PATCH] Allow FSM to thread single block cases too To: Richard Biener , Jan Hubicka References: <561CF734.7090802@redhat.com> Cc: GCC Patches From: Jeff Law Message-ID: <561E4DAD.9060702@redhat.com> Date: Wed, 14 Oct 2015 12:42:00 -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: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2015-10/txt/msg01354.txt.bz2 On 10/14/2015 04:16 AM, Richard Biener wrote: > On Tue, Oct 13, 2015 at 2:52 PM, Richard Biener > wrote: >> On Tue, Oct 13, 2015 at 2:21 PM, Jeff Law wrote: >>> >>> One of the cases that was missing in the FSM support is threading when the >>> path is a single block. ie, a control statement's output can be statically >>> determined just by looking at PHIs in the control statement's block for one >>> or incoming edges. >>> >>> This is necessary to fix a regression if I turn off the old jump threader's >>> backedge support. Just as important, Jan has in the past asked about a >>> trivial jump threader to be run during early optimizations. Limiting the >>> FSM bits to this case would likely satisfy that need in the future. >> >> I think he asked for trivial forward threads though due to repeated tests. >> I hacked FRE to do this (I think), but maybe some trivial cleanup opportunities >> are still left here. Honza? > > This or other related patches in the range r228731:228774 has caused a quite > big jump in SPEC CPU 2000 binary sizes (notably 176.gcc - so maybe affecting > bootstrap as well, at -O3). Are you sure this doesn't re-introduce DOM > effectively peeling all loops once? It's possible. I've actually got a patch in overnight testing that introduces some of the heuristics to avoid mucking up loops to the FSM bits. jeff