From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-309193-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 31323 invoked by alias); 19 Feb 2010 14:22:45 -0000
Received: (qmail 31277 invoked by uid 48); 19 Feb 2010 14:22:34 -0000
Date: Fri, 19 Feb 2010 14:22:00 -0000
Subject: [Bug c++/43120]  New: Diamond virtual inheritence with covariant return type confuses GCC
X-Bugzilla-Reason: CC
Message-ID: <bug-43120-10888@http.gcc.gnu.org/bugzilla/>
Reply-To: gcc-bugzilla@gcc.gnu.org
To: gcc-bugs@gcc.gnu.org
From: "goeran at uddeborg dot se" <gcc-bugzilla@gcc.gnu.org>
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: 2010-02/txt/msg01945.txt.bz2

Diamond shaped class structure with a covariant return method causes GCC to
fail to adjust base pointers.  In the attached program, the output is a huge
number instead of the expected 123.

Looking at what happens in GDB, it appears that the this pointer in the call of
A(const A &other) gets a B reference rather than an A reference.  The place
where it expects to find the member A::a is actually outside of the object of
type F.  If I'm reading the output from GDB correctly.


-- 
           Summary: Diamond virtual inheritence with covariant return type
                    confuses GCC
           Product: gcc
           Version: 4.4.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: goeran at uddeborg dot se


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43120