1! { dg-do compile }
2! { dg-options "-O1" }
3SUBROUTINE check_for_overlap (cell_length)
4  REAL, DIMENSION(1:3), INTENT(IN), OPTIONAL :: cell_length
5  REAL, DIMENSION(1:3) :: abc, box_length
6
7  IF (PRESENT(cell_length)) THEN
8    box_length(1:3)=abc(1:3)
9  ENDIF
10END SUBROUTINE check_for_overlap
11