From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id A1E3F3858001 for ; Tue, 15 Jun 2021 05:39:45 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org A1E3F3858001 Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-395-lQ9IqUKWOJiU-siiD7S1dA-1; Tue, 15 Jun 2021 01:39:43 -0400 X-MC-Unique: lQ9IqUKWOJiU-siiD7S1dA-1 Received: by mail-wr1-f70.google.com with SMTP id k25-20020a5d52590000b0290114dee5b660so8090910wrc.16 for ; Mon, 14 Jun 2021 22:39:43 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=XgBm92Mo+ojv4BigGRs5SWy3fDGbpb/6F1jo9gdSlPg=; b=qvpWjsqYptoANJbHL8356rahkc2Va9eyYg5UOgn05OaTLkbmi4zd/3+sNfM4zBVMaI ucsepWMvcyIuAtwa+ApBaksqGH/beEzTwW76aS61DW9QNwMIqpAq20WXGZKJIM2JNCoF aEDSlTHR6xV8dkuKVN+LEv8W/EZ83BeVjQS8OFZSkeFJ1vdi5X51Cun8uzvGNYyLld/6 uE/OElXvYCq9mEvXWzaAK40vvWHj3LkPUvTLYDLZg5otxFTLRhoytaWeW142U39DvUse jOSmpX2tS4BTHz0Xq70VKCWqc7+654tDcvNveygmPQAaomJTmcJDbYy9ndLPO+Bh95rD BSCA== X-Gm-Message-State: AOAM532lrwrQucjMMLImPew12JGKcjtVerbRnYaUNtoHeU9+hYJ7wHRd gk1re4FafL5TN6Zyu7rYVXq2akEFO3l4JeP0BHQXjYl1e1Fnm3NU2KAtlIpmYggkhZR51VAS/Jq kKggwW2Q= X-Received: by 2002:adf:fcce:: with SMTP id f14mr22959699wrs.215.1623735582853; Mon, 14 Jun 2021 22:39:42 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzZu0jvLX1KJ6BYqghQonnds7/tbrPIYqC+RMj7CeJmGfXuBjZVH6wDS8lfPiG93r5yCDMmgQ== X-Received: by 2002:adf:fcce:: with SMTP id f14mr22959682wrs.215.1623735582618; Mon, 14 Jun 2021 22:39:42 -0700 (PDT) Received: from abulafia.quesejoda.com ([95.169.237.215]) by smtp.gmail.com with ESMTPSA id o20sm1213012wms.3.2021.06.14.22.39.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 14 Jun 2021 22:39:42 -0700 (PDT) Subject: Re: replacing the backwards threader and more To: Jeff Law , Richard Biener Cc: GCC Mailing List , Andrew MacLeod References: <07775b9d-b8eb-48cb-57ef-9cc278d38967@redhat.com> From: Aldy Hernandez Message-ID: Date: Tue, 15 Jun 2021 07:39:41 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-3.7 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gcc@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Jun 2021 05:39:49 -0000 On 6/15/21 6:03 AM, Jeff Law wrote: > > > On 6/14/2021 12:40 AM, Richard Biener wrote: >> >>> I bet it's going to be tougher to remove DOM's threader.  It knows how >>> to do thinks like resolve memory references using temporary equivalences >>> and such.  But I bet it's enough to drop the VRP based threaders. >> Yes.  In fact I am wondering if adding threading to the not iterating FRE >> would make it possible to drop DOM, replacing it with instances of FRE. > I'd think so.  I'd approach as: > > 1. Remove the VRP threader instances. > 2. Drop cprop and redundancy elimination from DOM using FRE instead > 3. What's left of DOM is just forward jump threading.  Revamp & > simplify.  Then either make it a distinct pass or as a sub-pass of FRE. > > But one could just as easily look at adding threading to FRE and just > killing DOM and its jump threading. Andrew will hopefully be contributing the relational work this week. Once he does so, I will gather more granular stats for VRP1/VRP2 so we can assess the situation. Also, a bunch of tests needed to be tweaked because the new code picks up so many threads. I'm waiting for the relational work to avoid having to adjust the tests again. I would personally prefer to add an item 0 to the above list: replace current backwards threader code with the rewrite. I would hate to replace all threaders at once and deal with the fallout. Perhaps it's better to replace the backward threaders, and once that settles move onto VRP[12]?? Aldy