On 11/17/19 7:34 PM, Paul Richard Thomas wrote:
[…]
Sorry for not yet reviewing the code, but the following caught my eye:
(gfc_alloc_allocatable_for_assignment): […]
Force reallocation of unlimited
polymorphic lhs's. […]
[…]
! /* If the lhs is deferred length or unlimited polymorphic, assume that
! the element size changes and force a reallocation. */
! if (expr1->ts.deferred || UNLIMITED_POLY (expr1))
I wonder whether this assumption breaks code, which relies on a pointer
address not changing, cf. test case below.
I think the standard does not state explicitly that no reallocation
happens, but I think it can be deduced. In any case, the reallocation is
only supposed to happen for (F2018, 10.2.1.3p1):
"If the variable is an allocated allocatable variable, it is deallocated
ifexpr is an array of different shape, any corresponding length type
parameter values of the variable andexprdiffer, or the variable is
polymorphic and the dynamic type or any corresponding kind type
parameter values of the variable andexpr differ."
Cheers,
Tobias
implicit none (type, external)
integer, pointer :: ptr
class(*), target, allocatable :: alloc
allocate(integer :: alloc)
select type(alloc)
type is(integer)
alloc = 67
ptr => alloc
end select
call assign(alloc)
!print *, ptr
if (ptr /= 5) error stop 1
select type(alloc)
type is(integer)
!print *, alloc
if (ptr /= 5) error stop 2
end select
contains
subroutine assign(x)
class(*), allocatable :: x
x = 5
end subroutine assign
end
