From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-357242-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 3549 invoked by alias); 22 May 2011 11:12:39 -0000
Received: (qmail 3528 invoked by uid 22791); 22 May 2011 11:12:37 -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; Sun, 22 May 2011 11:12:22 +0000
From: "burnus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/49106] New: static variable is optimized away even though it is referenced by a nested constructor
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: middle-end
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: burnus 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: <bug-49106-4@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
Date: Sun, 22 May 2011 11:15:00 -0000
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: 2011-05/txt/msg01909.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49106

           Summary: static variable is optimized away even though it is
                    referenced by a nested constructor
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: burnus@gcc.gnu.org


In the following program, the function "test" is optimized way as the node is
not marked as needed. Thus, the static variable "a" is removed - even though it
is referenced in the nested constructor "_const_func".

Result: Link error:
/tmp/ccaIjMKk.o: In function `_const_func.1591':
test.c:(.text+0x6): undefined reference to `a.1589'

Expected: The local static should not be optimized way, i.e. the nested
function lowering should properly update the cgraph ipa reference list.


Side remark: For my purpose (coarray initialization in gfortran) it would be
best if in such a case both the function and the constructor could be optimized
away. Thus, if there would be some method on tree-level to tell this cgraph ...


main ()
{
  void test (void)
  {
    static int a;
    void __attribute__((constructor))
    _const_func(void)
    {
      a = 7;
    }
  }
  return 0;
}