From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29486 invoked by alias); 19 Nov 2013 22:16:39 -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 29428 invoked by uid 48); 19 Nov 2013 22:16:35 -0000 From: "law at redhat dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/42145] Incorrect "may be used uninitialized warning" for a very specific test case Date: Tue, 19 Nov 2013 22:16:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Version: 4.5.0 X-Bugzilla-Keywords: diagnostic X-Bugzilla-Severity: normal X-Bugzilla-Who: law at redhat dot com X-Bugzilla-Status: NEW 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: cc 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: 2013-11/txt/msg01894.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42145 Jeffrey A. Law changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |law at redhat dot com --- Comment #5 from Jeffrey A. Law --- -Os disables jump threading except for very specific circumstances because the block duplication generally increases code size. As a result of restricting the optimizer, certain paths through the CFG which are unexecutable have to be left in the CFG which leads to the false positive.