From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1074 invoked by alias); 7 May 2012 14:31:07 -0000 Received: (qmail 1051 invoked by uid 22791); 7 May 2012 14:31:03 -0000 X-SWARE-Spam-Status: No, hits=-4.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00,KHOP_THREADED 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; Mon, 07 May 2012 14:30:51 +0000 From: "jason at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/53220] [4.7/4.8 Regression] g++ mis-compiles compound literals Date: Mon, 07 May 2012 14:33:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c++ X-Bugzilla-Keywords: wrong-code X-Bugzilla-Severity: normal X-Bugzilla-Who: jason 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: 4.8.0 X-Bugzilla-Changed-Fields: CC Target Milestone 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 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: 2012-05/txt/msg00794.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53220 Jason Merrill changed: What |Removed |Added ---------------------------------------------------------------------------- CC|jason at redhat dot com |jason at gcc dot gnu.org Target Milestone|4.7.1 |4.8.0 --- Comment #4 from Jason Merrill 2012-05-07 14:29:52 UTC --- Compound literals are not part of C++, so correctness is a matter of debate. In C, a compound literal designates an object with automatic storage duration. In G++, a compound literal designates a temporary object, just like a normal cast or function-like cast. This is a significant difference in semantics, which leads to the problem encountered here; the temporary object goes out of scope immediately after the initialization of p, so the loop has undefined behavior. It would be possible for G++ to model the C semantics more closely.