https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127732
Bug ID: 127732
Summary: Wrong LBOUND of SELECT TYPE associate name when the
polymorphic selector is not a whole array
Product: gcc
Version: 16.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: ivan.pribec at gmail dot com
Target Milestone: ---
The cases below demonstrates some discrepancies when an associate name in a
SELECT TYPE statement is not a whole array:
! Check bounds in select type statement with polymorphic selector
!
! Each line prints lbound ubound size. Expected:
! case 1 (control): 2 4 3
! cases 2 to 5: 1 3 3
!
! Assisted by: Claude Fable 5.1
module m
implicit none
real, target :: rt(2:4) = [20., 30., 40.]
contains
function fa() result(r) ! CLASS(*) allocatable, bounds 2:4
class(*), allocatable :: r(:)
allocate (r, source=rt)
end function
end module
program p
use m
implicit none
character(*), parameter :: fmt = '(a,t44,3i4)'
class(*), pointer :: q(:)
q(2:) => rt
! 1. Pointer, whole array (control)
select type (x => q)
type is (real)
print fmt, '1 pointer, whole array (control)', lbound(x), ubound(x),
size(x)
end select
! 2. Array section of a pointer
select type (x => q(:))
type is (real)
print fmt, '2 array section q(:)', lbound(x), ubound(x), size(x)
end select
! 3. Parenthesized pointer (an expression)
select type (x => (q))
type is (real)
print fmt, '3 parenthesized pointer (q)', lbound(x), ubound(x), size(x)
end select
! 4. Allocatable function result
select type (x => fa())
type is (real)
print fmt, '4 allocatable function result fa()', lbound(x), ubound(x),
size(x)
end select
! 5. ASSOCIATE name of an allocatable function result
associate (a => fa())
select type (a)
type is (real)
print fmt, '5 ASSOCIATE (a => fa()), SELECT TYPE (a)', lbound(a),
ubound(a), size(a)
end select
end associate
end program
Results from gfortran:
1 pointer, whole array (control) 2 4 3
2 array section q(:) 2 4 3
3 parenthesized pointer (q) 2 4 3
4 allocatable function result fa() 2 4 3
5 ASSOCIATE (a => fa()), SELECT TYPE (a) 2 4 3
Results from flang:
1 pointer, whole array (control) 2 4 3
2 array section q(:) 1 3 3
3 parenthesized pointer (q) 1 3 3
4 allocatable function result fa() 1 3 3
5 ASSOCIATE (a => fa()), SELECT TYPE (a) 1 3 3
Results from ifx:
1 pointer, whole array (control) 2 4 3
2 array section q(:) 1 3 3
3 parenthesized pointer (q) 1 3 3
4 allocatable function result fa() 2 4 3
5 ASSOCIATE (a => fa()), SELECT TYPE (a) 1 3 3
