[Bug fortran/59440] New: [4.9 Regression] ICE in force_decl_die, at dwarf2out.c:20111 with -g

["anlauf at gmx dot de" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59440

            Bug ID: 59440
           Summary: [4.9 Regression] ICE in force_decl_die, at
                    dwarf2out.c:20111 with -g
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: anlauf at gmx dot de

Hi,

with 4.9.0 rev.205822 the following code crashes with:

gfcbug126.f90:2:0: internal compiler error: in force_decl_die, at
dwarf2out.c:20111
   use mo_t_datum, only: qbit_conv
 ^
0x83eae74 force_decl_die
        ../../trunk/gcc/dwarf2out.c:20111
0x83eb3be gen_namelist_decl
        ../../trunk/gcc/dwarf2out.c:20632
0x83e9087 gen_decl_die
        ../../trunk/gcc/dwarf2out.c:20435
0x86d0e80 emit_debug_global_declarations(tree_node**, int)
        ../../trunk/gcc/toplev.c:532
0x858faee write_global_declarations()
        ../../trunk/gcc/langhooks.c:327

% cat mo_t_datum.f90
module mo_t_datum
  implicit none
  integer :: qbit_conv = 0
end module mo_t_datum
% cat gfcbug126.f90
MODULE gfcbug126
  use mo_t_datum, only: qbit_conv
  implicit none
  namelist /OBSERVATIONS/ qbit_conv
end module gfcbug126

Command line:

% /opt/gcc/4.9/bin/gfortran  -c mo_t_datum.f90 gfcbug126.f90 -g

It is important that the code is split into 2 files, otherwise there is
no crash.