Bug#401496: gfortran-4.1 bug / ICE in gfc_conv_constant at fortran-trans-const.c:348

[Jonathan Stott <jonathan.stott@utoronto.ca>]

Package: gfortran-4.1
Version: 4.1.1-19
The source code below generates an internal compiler error.  The error
is somehow related with to the two initialization of the two constants
n1 and n2.  The exact command-line arguments used appear to be irrelevant.

Gfortran version report and compiler error are in the code comments.

-Jonathan

PS. The loadcfg() subroutine is probably innocent, but I forgot to
delete it and I'm not running under Linux at the moment to verify it.

! ----------------------------------------------------------------------
!~/source> gfortran -c testbug.f90
!testbug.f90: In function 'xstrcmp':
!testbug.f90:11: internal compiler error: in gfc_conv_constant, at
fortran/trans-const.c:348
!Please submit a full bug report,
!with preprocessed source if appropriate.
!See <URL:http://gcc.gnu.org/bugs.html> for instructions.
!For Debian GNU/Linux specific bug reporting instructions,
!see <URL:file:///usr/share/doc/gcc-4.1/README.Bugs>.
!
!~/source> gfortran --version
!GNU Fortran 95 (GCC) 4.1.2 20061028 (prerelease) (Debian 4.1.1-19)
!Copyright (C) 2006 Free Software Foundation, Inc.
!
!GNU Fortran comes with NO WARRANTY, to the extent permitted by law.
!You may redistribute copies of GNU Fortran
!under the terms of the GNU General Public License.
!For more information about these matters, see the file named COPYING
! ----------------------------------------------------------------------

! ----------------------------------------------------------------------
! Load in configuration files.

module cfgfile
  ! Module variables used to be here

contains
  ! --------------------------------------------------------------------
  ! Read parameters out of the file - probably irrelevant.

  subroutine loadcfg(fname)
    character*(*), intent(in) :: fname

    open(unit=2, file=fname, status='old', iostat=ierr)

    ! File parser used to be here

    close(2)

    return
  end subroutine loadcfg

  ! --------------------------------------------------------------------
  ! Compare 2 strings - THIS CAUSES A COMPILER CRASH

  integer function xstrcmp(s1, s2)
    implicit none

    character*(*), intent(in) :: s1, s2
    integer :: i, n1 = len(s1), n2 = len(s2)

    ! If I don't ever reference n1,n2 then I won't have a problem.
    n1 = 1
    n2 = 2

    ! Comparison code used to be here

    xstrcmp = -1

    return
  end function xstrcmp
end module cfgfile

! ----------------------------------------------------------------------
! MAIN PROGRAM

program testcfg
  use cfgfile

  call loadcfg('test.cfg')

  return
end program testcfg