[Bug fortran/53389] New: memory leak when assigning array function result to allocatable array, where one of its supplied arguments is itself an array function result.

["stephan.kramer at imperial dot ac.uk" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53389

             Bug #: 53389
           Summary: memory leak when assigning array function result to
                    allocatable array, where one of its supplied arguments
                    is itself an array function result.
    Classification: Unclassified
           Product: gcc
           Version: 4.7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: stephan.kramer@imperial.ac.uk


The following test code leaks memory rapidly - reproduced on Ubuntu's gfortran
4.6.3, with gfortran 4.7.1 and with a nightly build of 4.8, trunk revision
187620 - default optimisation flags (none specified). As far as I've narrowed
it down, it seems to occur when an array function result is assigned to an
allocatable array, where one of the arguments supplied to this function is
itself an array function result. In the example below, the outer function and
the function supplied as an argument are the same, and the returned array is an
automatic array, but that does not seems to be necessary to reproduce the
problem.

module foo
  implicit none
  contains

  function filler(array, val)
    real, dimension(:), intent(in):: array
    real, dimension(size(array)):: filler
    real, intent(in):: val

    filler=val

  end function filler
end module

program test
  use foo
  implicit none

  real, dimension(:), allocatable:: x, y
  integer, parameter:: N=1000*1000
  integer:: i

  allocate( x(N), y(N) )
  y=0.0

  do i=1, N
    print *,i
    x=filler(filler(y, real(2*i)), real(i))
    y=y+x
  end do

end program test