From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-391191-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 21913 invoked by alias); 7 May 2012 16:29:14 -0000
Received: (qmail 21902 invoked by uid 22791); 7 May 2012 16:29:10 -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 16:28:58 +0000
From: "ppluzhnikov at google dot com" <gcc-bugzilla@gcc.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 16:55:00 -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: ppluzhnikov at google dot com
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:
Message-ID: <bug-53220-4-oW6MqWrmOo@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-53220-4@http.gcc.gnu.org/bugzilla/>
References: <bug-53220-4@http.gcc.gnu.org/bugzilla/>
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: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2012-05/txt/msg00809.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53220

--- Comment #6 from Paul Pluzhnikov <ppluzhnikov at google dot com> 2012-05-07 16:28:56 UTC ---
(In reply to comment #5)

> 1) to keep the current G++ semantics of compound literals, but change its
> behavior due to the implementation change (with clobber marker); 

I would argue that 1 is completely useless for "you can also construct an
array" use case from http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html

It always initializes the pointer with dangling storage, and is always a bug.

If "keep the current g++ semantics", then the code should be rejected at
compile time, and should *not* work when built without optimization.

IMO, having this code working in C and not working in C++ is a lousy choice.