From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 67876 invoked by alias); 24 Jun 2019 14:28:45 -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 67868 invoked by uid 89); 24 Jun 2019 14:28:45 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-2.4 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS autolearn=ham version=3.3.1 spammy=luck 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 ESMTP; Mon, 24 Jun 2019 14:28:44 +0000 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7A18A7FDFD; Mon, 24 Jun 2019 14:28:40 +0000 (UTC) Received: from tucnak.zalov.cz (ovpn-116-51.ams2.redhat.com [10.36.116.51]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1A6CA60BF7; Mon, 24 Jun 2019 14:28:38 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.15.2/8.15.2) with ESMTP id x5OESaWw000306; Mon, 24 Jun 2019 16:28:37 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.15.2/8.15.2/Submit) id x5OESYtD000305; Mon, 24 Jun 2019 16:28:34 +0200 Date: Mon, 24 Jun 2019 14:28:00 -0000 From: Jakub Jelinek To: gcc-patches@gcc.gnu.org, richard.sandiford@arm.com Subject: Re: [PATCH 0/3] RFC: Let debug stmts influence codegen at -Og Message-ID: <20190624142834.GL815@tucnak> Reply-To: Jakub Jelinek References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) X-IsSubscribed: yes X-SW-Source: 2019-06/txt/msg01459.txt.bz2 On Sun, Jun 23, 2019 at 02:51:06PM +0100, Richard Sandiford wrote: > What do you think? Is it worth pursuing this further? Wouldn't it be more useful to just force all automatic variables to be used at the end of their corresponding scope? That is IMHO the main issue with -Og debugging, VTA is a best effort, if we can express a variable with some expression, nice, but if there is no expression nor memory nor register that holds the value, we are out of luck. Could be some magic stmt like gimple_clobber or ifn or something similar, which would make sure that at least until expansion to RTL we force those vars to be live in either a register or memory. I'm afraid having different modes, one in which debug stmts can't and one where they can affect code generation might be a maintainance nightmare. Jakub