[Bug fortran/106771] New: [OOP] ICE with PACK intrinsic, in gfc_conv_expr_descriptor, at fortran/trans-array.c:7328

["federico.perini at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106771

            Bug ID: 106771
           Summary: [OOP] ICE with PACK intrinsic, in
                    gfc_conv_expr_descriptor, at
                    fortran/trans-array.c:7328
           Product: gcc
           Version: 9.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: federico.perini at gmail dot com
  Target Milestone: ---

I'm getting an ICE using the PACK intrinsic from within a polymorphic entity.
There are several similar bugs reported, but none seems to address PACK, so I'm
opening a new ticket. BTW: I've tested it on godbolt (try here:
https://godbolt.org/z/cnj6PzqKz)
And it looks like: 

WORKS on: 10.4.0, 11 (all), 12 (all)
ICE   on: 4.9, 5-8 (all), 9 (all), 10.1, 10.2, 10.3

The mask is created from a polymorphic elemental function on the object
Here's a minimal example: 

module test
    implicit none

    type::t
       integer, allocatable :: iloc(:)
       contains 
          procedure :: is_active => isa
          procedure :: list2loc => myfun_poly
    end type t

    contains

    elemental logical function isa(this,i)
       class(t), intent(in) :: this
       integer, intent(in) :: i
       if (i>0 .and. i<=merge(size(this%iloc),0,allocated(this%iloc))) then 
          isa = this%iloc(i)>0
       else
          isa = .false.
       endif  
    end function isa

    ! internal compiler error: in gfc_conv_expr_descriptor, at
fortran/trans-array.c:7328
    function myfun_poly(this,IDs) result (ilocs)
        class(t), intent(in) :: this
        integer, intent(in) :: IDs(:)
        integer, allocatable :: ilocs(:)
        if (size(IDs)<=0) then
           allocate(ilocs(0))
        else
           ilocs = pack(this%iloc(IDs),this%is_active(ilocs))
        endif
    end function myfun_poly

    ! WORKS
    function myfun(this,IDs) result (ilocs)
        type(t), intent(in) :: this
        integer, intent(in) :: IDs(:)
        integer, allocatable :: ilocs(:)
        if (size(IDs)<=0) then
           allocate(ilocs(0))
        else
           ilocs = pack(this%iloc(IDs),this%is_active(ilocs))
        endif
    end function myfun
end module test    

program testp
   use test
   implicit none

   type(t) :: a

   integer :: rnd(100)
   real :: x(100)
   integer, allocatable :: list(:)

   call random_number(x); rnd = ceiling(x*100)

   ! Works
   list = myfun(a,rnd)
   ! ICE
   list = a%list2loc(rnd)

   print *, 'list=',list

end program testp


Hope this helps,
federico