[Bug fortran/54992] New: [OOP] Wrong offset in the array offset calculation when using nonclass%class(index)%nonclass

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54992



             Bug #: 54992

           Summary: [OOP] Wrong offset in the array offset calculation

                    when using nonclass%class(index)%nonclass

    Classification: Unclassified

           Product: gcc

           Version: 4.8.0

            Status: UNCONFIRMED

          Keywords: wrong-code

          Severity: normal

          Priority: P3

         Component: fortran

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: bur...@gcc.gnu.org

                CC: ja...@gcc.gnu.org, pa...@gcc.gnu.org





As reported by Andrew Benson in the thread starting at

http://gcc.gnu.org/ml/fortran/2012-10/msg00087.html



The problem is that gfortran generates the wrong code for:



    targetNode%cBh(2)%hostNode => targetNode



where "cBh" is a polymorphic array. The offset is calculated as



  ((base_type *)targetNode->_data->cBh->_data)[ index ].host





Instead of the proper:



  targetNode->_data->cBh->_data.data

               + (index * targetNode->_data->cBh->_vptr_size)





Test case:  http://gcc.gnu.org/ml/fortran/2012-10/msg00100.html



Analysis:   http://gcc.gnu.org/ml/fortran/2012-10/msg00101.html