[Bug fortran/98307] New: use "allocatable" instead of "pointer" (forall_3.f90)

[xiao.liu--- via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98307

            Bug ID: 98307
           Summary: use "allocatable" instead of "pointer" (forall_3.f90)
           Product: gcc
           Version: 10.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: xiao....@compiler-dev.com
  Target Milestone: ---

in the test case "gfortran.fortran-torture/execute/forall_3.f90", if replace
"pointer" with "allocatable", the result will be different.

program evil_forall
  implicit none
  type t
    logical valid
    integer :: s
    !integer, dimension(:), pointer :: p
    integer, dimension(:), allocatable :: p
  end type
  type (t), dimension (5) :: v
  integer i

  allocate (v(1)%p(2))
  allocate (v(2)%p(8))
  !v(3)%p => NULL()
  allocate (v(4)%p(8))
  allocate (v(5)%p(2))

  v(:)%valid = (/.true., .true., .false., .true., .true./)
  v(:)%s = (/1, 8, 999, 6, 2/)
  v(1)%p(:) = (/9, 10/)
  v(2)%p(:) = (/1, 2, 3, 4, 5, 6, 7, 8/)
  v(4)%p(:) = (/13, 14, 15, 16, 17, 18, 19, 20/)
  v(5)%p(:) = (/11, 12/)


  forall (i=1:5,v(i)%valid)
    v(i)%p(1:v(i)%s) = v(6-i)%p(1:v(i)%s)
  end forall

  if (any(v(1)%p(:) .ne. (/11, 10/))) STOP 1
  if (any(v(2)%p(:) .ne. (/13, 14, 15, 16, 17, 18, 19, 20/))) STOP 2
  if (any(v(4)%p(:) .ne. (/1, 2, 3, 4, 5, 6, 19, 20/))) STOP 3
  if (any(v(5)%p(:) .ne. (/9, 10/))) STOP 4

  ! I should really free the memory I've allocated.
end program

the result is "STOP 3"