From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29368 invoked by alias); 24 Aug 2018 19:52:50 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 29357 invoked by uid 89); 24 Aug 2018 19:52:50 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY,SPF_HELO_PASS autolearn=no version=3.3.2 spammy=palves, Hx-languages-length:1433 X-HELO: mx1.redhat.com Received: from mx3-rdu2.redhat.com (HELO mx1.redhat.com) (66.187.233.73) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 24 Aug 2018 19:52:49 +0000 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B7B437DAC2; Fri, 24 Aug 2018 19:52:47 +0000 (UTC) Received: from [127.0.0.1] (ovpn04.gateway.prod.ext.ams2.redhat.com [10.39.146.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id DF75B1007254; Fri, 24 Aug 2018 19:52:46 +0000 (UTC) Subject: Re: GDB 8.2 release 2018-08-21 status update To: Simon Marchi References: <20180821175136.GA3365@adacore.com> <0e24ffbeb9706f75c53d3fdcfea3decb@polymtl.ca> <20180823154138.66be5572@pinnacle.lan> Cc: Kevin Buettner , gdb-patches@sourceware.org, Joel Brobecker From: Pedro Alves Message-ID: <23af714e-9fd0-f86c-e1f1-66f4931d3a20@redhat.com> Date: Fri, 24 Aug 2018 19:52:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-SW-Source: 2018-08/txt/msg00602.txt.bz2 On 08/24/2018 08:14 PM, Simon Marchi wrote: > On 2018-08-24 14:35, Pedro Alves wrote: >> Unless I'm wrong that >> -freorder-blocks-and-partition is on by default in GCC 8 already? > > Looking at gcc/doc/invoke.texi, apparently it's been enabled for -O2/-O3 for some time and more recently -Os.  You can check whether it is enabled with: > >   gcc -Q -v --help 2>/dev/null | grep reorder-blocks-and-partition > > I see it as disabled by default and enabled if I add -O2, with different gcc versions between 5.4.0 and 8.2.0.  So it doesn't seem to have changed recently.  Maybe what changed is that gcc 8 partitions more aggressively?  Or it's just that gcc developers tend to debug -O2 builds?  I have no idea. Here's what Jakub Jelinek had to say about it: is -freorder-blocks-and-partition on by default in any gcc release yet? palves: yes, in gcc 8 palves: for older releases I believe it has been enabled, but due to a bug actually disabled later on, unless -fprofile-use was used palves: "-freorder-blocks-and-partition, a pass splitting function bodies into hot and cold regions, is now enabled by default at -O2 and higher for x86 and x86-64." is in gcc.gnu.org/gcc-8/changes.html palves: it was added for -fprofile-use initially, and its test coverage was using usually explicit -freorder-blocks-and-partition Thanks, Pedro Alves