[Bug fortran/44879] New: MOVE_ALLOC rejects FROM= which is a function result

[Bug fortran/44879] New: MOVE_ALLOC rejects FROM= which is a function result

[burnus at gcc dot gnu dot org]

>From Reinhold Bader at http://j3-fortran.org/pipermail/j3/2010-July/003653.html

The following program is rejected with:

  call move_alloc(extd(i1), i1)
                  1
Error: 'from' argument of 'move_alloc' intrinsic at (1) must be a variable


The standard does not say anything about "variable":
"FROM may be of any type and rank. It shall be allocatable. It is an INTENT
(INOUT) argument."

The check is done at gfc_check_move_alloc. It might be sufficient to replace:

  if (variable_check (from, 0) == FAILURE)
    return FAILURE;
by
  if (from->expr_type != EXPR_VARIABLE && ... != EXPR_FUNCTION)
    { gfc_error ...; return FAILURE }

The rest (e.g. gfc_variable_attr) can deal with it.


program mvall_01
  implicit none
  integer, parameter :: n1 = 100, n2 = 2*n1
  integer, allocatable :: i1(:)

  allocate(i1(n1))
  i1 = 1
  call move_alloc(extd(i1), i1)
  print *, i1(1), size(i1)
  if (i1(1) /= 2 .or. size(i1) /= 200) call abort()
contains
  function extd(in) result(out)
    integer, allocatable :: out(:)
    integer, intent(in) :: in(:)
    allocate(out(2*size(in)))
    out = 2
  end function
end program


-- 
           Summary: MOVE_ALLOC rejects FROM= which is a function result
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44879

[Bug fortran/44879] MOVE_ALLOC rejects FROM= which is a function result

[burnus at gcc dot gnu dot org]

------- Comment #1 from burnus at gcc dot gnu dot org  2010-07-09 05:47 -------
As Malcom Cohen points out:

"If a dummy argument has INTENT (OUT) or INTENT (INOUT), the actual argument
shall be definable." (F2008, 12.5.2.4, paragraph 17)

And as "FROM" is a "INTENT(INOUT) argument." (cf. above), it needs to be
definable and thus may not be a function (result). That's exactly what gfortran
checks :-)

Close as invalid.


-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44879

[Bug fortran/44879] MOVE_ALLOC rejects FROM= which is a function result

[kargl at gcc dot gnu dot org]

------- Comment #2 from kargl at gcc dot gnu dot org  2010-07-09 06:02 -------
Is there a testsuite program to check this?
Perhaps, your code should be added so the
correct behavior doesn't get unfixed.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44879