[Bug fortran/85537] [7/8/9 Regression] Invalid memory reference at runtime when calling subroutine through procedure pointer

[janus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85537

--- Comment #6 from janus at gcc dot gnu.org ---
(In reply to janus from comment #5)
> However I don't see any failures with this variant:

Sorry, I was a bit too quick in submitting this. It's really not a good
example, since it's missing an "implicit none", so "bar_impl" supposedly gets
its own private version of "a".

The following variant fails again in the same way as the original test case:


program main

   implicit none
   integer :: a

   call foo()

contains

   subroutine foo()

      abstract interface
         subroutine ibar()
         end subroutine
      end interface

      procedure(ibar), pointer :: bar_ptr => bar_impl

      a = 0
      call bar_impl()
      call bar_ptr()

   end subroutine


   subroutine bar_impl()
      write (*,*) "foo"
      a = a + 1
   end subroutine

end program


I don't quite understand what's going on. Apparently the reference to the
variable 'a' somehow goes wrong. But I don't see how the procedure pointer
makes a difference here.