From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24559 invoked by alias); 6 Aug 2014 02:00:17 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 23477 invoked by uid 48); 6 Aug 2014 02:00:02 -0000 From: "vmakarov at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug debug/61923] [4.8/4.9/4.10 Regression] -fcompare-debug errors while building Linux kernel. Date: Wed, 06 Aug 2014 02:00:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: debug X-Bugzilla-Version: 4.8.3 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: vmakarov at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.8.4 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-08/txt/msg00326.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61923 --- Comment #5 from Vladimir Makarov --- The difference after scheduling a block is in DFA state because of additional advance_one_cycle call when debug_insns are present. The situation looks like -g last bb insn last real bb insn -> advance_one_cycle ->advance_one_cycle debug_insn ->advance_one_cycle Last advance cycle is done at the end of processing all bb insns. I'll try to produce a patch tomorrow to fix it which is not easy as schedule_block is now very complicated function working in many modes and containing a lot of gotos.