From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15046 invoked by alias); 13 May 2011 20:59:33 -0000 Received: (qmail 15033 invoked by uid 22791); 13 May 2011 20:59:33 -0000 X-SWARE-Spam-Status: No, hits=-2.7 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 13 May 2011 20:59:18 +0000 From: "pkoning at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/48990] MIPS wrong code error with -O1 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Keywords: X-Bugzilla-Severity: major X-Bugzilla-Who: pkoning at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Date: Fri, 13 May 2011 21:09:00 -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 X-SW-Source: 2011-05/txt/msg01127.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48990 --- Comment #6 from Paul Koning 2011-05-13 20:29:50 UTC --- Created attachment 24243 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24243 debug dump from the pass before machdep After some debugging, I see that the problem is that register 4 (A0) is marked dead in the prologue, and then afterwards is still used. This causes the delay slot fill logic to believe it can put li $4,32 into the delay slot -- because it appears not to be needed. So the question now is why that register is marked dead and still used.