From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 12101 invoked by alias); 9 May 2015 05:01:14 -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 12073 invoked by uid 48); 9 May 2015 05:01:10 -0000 From: "trippels at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/66083] Linux kernel fails to boot with O3 optimization Date: Sat, 09 May 2015 05:01:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c X-Bugzilla-Version: 4.9.2 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: trippels at gcc dot gnu.org X-Bugzilla-Status: WAITING X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- 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: 2015-05/txt/msg00740.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66083 --- Comment #4 from Markus Trippelsdorf --- (In reply to Pranith Kumar from comment #3) > The kernel fails to boot. It works using 4.7/4.8 but 4.9 does not work. Not > sure what you mean which file. How do I pin point that? You could start with the failing kernel and replace object files with good ones until it boots (or vice versa). Once you have pinpoint the file in question you can use __attribute__((optimize(O2)) to narrow the issue down to a single function.