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 [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 12AE73858C52 for ; Wed, 22 Mar 2023 12:38:21 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 12AE73858C52 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679488700; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=GXpcgOy4EGa2sdeWzY0ZlMxcriEC327xEJDh7KeUlOE=; b=BcwqpYOXU2uIW93N+FVfr9OgwAlOmU9TRjO3ibMkoDNNRfvbczvDQIwe1ljBwSKVHOLaFy DeSPwaPsl/qqLg4PEeK2ojnzn7HC3Lbluq2BSE+98bcRyoWcD2qB6bzVGeMb+EAHFQkC6A kt1xlMIq3LfpqPVB0zMOPW3SSmLqHXo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-80-WO9Lkm0zO3m07fV42ZBZtw-1; Wed, 22 Mar 2023 08:38:17 -0400 X-MC-Unique: WO9Lkm0zO3m07fV42ZBZtw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 45FCF884624; Wed, 22 Mar 2023 12:38:17 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.192.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0949B2166B29; Wed, 22 Mar 2023 12:38:16 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 32MCcEes3397648 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Wed, 22 Mar 2023 13:38:14 +0100 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 32MCcDHn3397647; Wed, 22 Mar 2023 13:38:13 +0100 Date: Wed, 22 Mar 2023 13:38:13 +0100 From: Jakub Jelinek To: Richard Biener Cc: gcc-patches@gcc.gnu.org Subject: Re: [PATCH] tree-optimization/109237 - last_stmt is possibly slow Message-ID: Reply-To: Jakub Jelinek References: <90515.123032208295400168@us-mta-397.us.mimecast.lan> MIME-Version: 1.0 In-Reply-To: <90515.123032208295400168@us-mta-397.us.mimecast.lan> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-3.3 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Wed, Mar 22, 2023 at 12:29:52PM +0000, Richard Biener wrote: > Most uses of last_stmt are interested in control transfer stmts > and for the testcase gimple_purge_dead_eh_edges shows up in > the profile. But last_stmt looks past trailing debug stmts but > those would be rejected by GIMPLEs verify_flow_info. The following > adds possible_ctrl_stmt besides last_stmt which does not look > past trailing debug stmts and adjusts gimple_purge_dead_eh_edges. > > I've put checking code into possible_ctrl_stmt that it will not > miss a control statement if the real last stmt is a debug stmt. > > The alternative would be to change last_stmt, explicitely introducing > last_nondebug_stmt. I remember we chickened out and made last_stmt > conservative here but not anticipating the compile-time issues this > creates. I count 227 last_stmt and 12 last_and_only_stmt uses. > > Bootstrapped and tested on x86_64-unknown-linux-gnu. > > Any opinions? I probably lean towards s/last_stmt/last_nondebug_stmt/ > in next stage1 and then adding last_stmt and changing some > uses back - through for maintainance that's going to be a > nightmare (or maybe not, a "wrong" last_stmt should be safe to > backport and a last_nondebug_stmt will fail to build). > > Richard. > > PR tree-optimization/109237 > * tree-cfg.h (possible_ctrl_stmt): New function returning > the last stmt not skipping debug stmts. > (gimple_purge_dead_eh_edges): Use it. LGTM. But finding out which of those 227+12 calls want to skip debug stmts and which don't will be a nightmare... Jakub