[Bug middle-end/49062] New: [4.7 regression] Many C++ tests ICE on Tru64 UNIX: non-DECL_ONE_ONLY node in a same_comdat_group list

["ro at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49062

           Summary: [4.7 regression] Many C++ tests ICE on Tru64 UNIX:
                    non-DECL_ONE_ONLY node in a same_comdat_group list
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: ro@gcc.gnu.org
                CC: hubicka@gcc.gnu.org
              Host: alpha-dec-osf5.1b
            Target: alpha-dec-osf5.1b
             Build: alpha-dec-osf5.1b


Between 20110502 and 20110518, many C++ tests stated to ICE on Tru64 UNIX
(Alpha/ECOFF without COMDAT support), e.g.

FAIL: g++.dg/torture/covariant-1.C  -O0  (internal compiler error)
FAIL: g++.dg/torture/covariant-1.C  -O0  (test for excess errors)
Excess errors:
/vol/gcc/src/hg/trunk/local/gcc/testsuite/g++.dg/torture/covariant-1.C:33:1:
error: non-DECL_ONE_ONLY node in a same_comdat_group list
AB* AB::_ZTchn8_h8_N2AB7getThisEv()/4 @166940 (asm: _ZTchn8_h8_N2AB7getThisEv)
(same comdat group as AB* AB::_ZTch0_h8_N2AB7getThisEv()/3)
availability:available analyzed needed address_taken externally_visible
finalized asm_written
  thunk of AB* AB::_ZTch0_h8_N2AB7getThisEv() (asm: _ZTch0_h8_N2AB7getThisEv)
fixed offset -8 virtual value 0 has virtual offset 0)
  called by: 
  calls: AB* AB::_ZTch0_h8_N2AB7getThisEv()/3 (1.00 per call) 
  References: 
  Refering this function:  var:int (* AB::_ZTV2AB [6])(...) (addr)
/vol/gcc/src/hg/trunk/local/gcc/testsuite/g++.dg/torture/covariant-1.C:33:1:
internal compiler error: verify_cgraph_node failed

This is almost certainly due to this patch:

2011-05-06  Jan Hubicka  <jh@suse.cz>

    * cgraph.c (cgraph_add_thunk): Create real function node instead
    of alias node; finalize it and mark needed/reachale; arrange visibility
    to be right and add it into the corresponding same comdat group list.
    (dump_cgraph_node): Dump thunks.

Please fix.

  Rainer