From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 76603 invoked by alias); 6 May 2016 14:46:37 -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 76412 invoked by uid 89); 6 May 2016 14:46:36 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-4.0 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=Pick, HContent-Transfer-Encoding:8bit 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; Fri, 06 May 2016 14:46:32 +0000 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (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 2525462653; Fri, 6 May 2016 14:46:31 +0000 (UTC) Received: from tucnak.zalov.cz (ovpn-113-135.phx2.redhat.com [10.3.113.135]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u46EkTKr000841 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 6 May 2016 10:46:30 -0400 Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.15.2/8.15.2) with ESMTP id u46EkQQq000691; Fri, 6 May 2016 16:46:27 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.15.2/8.15.2/Submit) id u46EkOrS000689; Fri, 6 May 2016 16:46:24 +0200 Date: Fri, 06 May 2016 14:46:00 -0000 From: Jakub Jelinek To: Martin =?utf-8?B?TGnFoWth?= Cc: Yury Gribov , GCC Patches Subject: Re: [PATCH, RFC] Introduce -fsanitize=use-after-scope Message-ID: <20160506144624.GM26501@tucnak.zalov.cz> Reply-To: Jakub Jelinek References: <572C7A3E.4000905@suse.cz> <572C848E.9020705@samsung.com> <572C9963.9020207@suse.cz> <20160506132528.GK26501@tucnak.zalov.cz> <572CAD25.2040804@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <572CAD25.2040804@suse.cz> User-Agent: Mutt/1.5.24 (2015-08-30) X-IsSubscribed: yes X-SW-Source: 2016-05/txt/msg00506.txt.bz2 On Fri, May 06, 2016 at 04:41:41PM +0200, Martin Liška wrote: > On 05/06/2016 03:25 PM, Jakub Jelinek wrote: > > Well, we already have the gimple poisoning/unpoisoning code on RTL (emitted > > after the prologue and before the epilogue), so it shouldn't be that hard. > > I'd only do the most common/easy cases inline though, like 1/2/4/8/16/32 > > bytes long variables. > > > > Jakub > > You are right, I didn't realize it earlier. > As I've collected statistics for tramp3d, poisoning code has following distribution: > > 4:1.62% > 8:3.53% > 12:94.76% > > which is quite interesting that 12B are such a common size :) > Probably due to a lot of time spent in ::evaluate (MultiArgEvaluator and MultiArgEvaluator). > Considering just variables which needs_to_live_in_memory, tramp3d is still ~15x slower. Please look at other testcases, not just tramp3d - we in the end don't want to tune it to just tramp3d. Pick up some 3-4 C/C++ benchmarks, tramp3d can be one of them ;) Jakub