[Bug fortran/38863] WHERE with multiple elemental defined assignments gives wrong answer

["mikael at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #1 from mikael at gcc dot gnu dot org  2009-01-18 20:40 -------
I suspect the following  is invalid as the arguments to the defined assignment
alias. 

      WHERE(LDA)
        TLA2L = TLA2L(1:3,1:2)%L     !removing this line fixes problem
        TLA2L = TLA2L(1:3,1:2)%I
      ELSEWHERE
        TLA2L = -1
      ENDWHERE

However, the following is valid (I think):

     module m

     type t
        integer :: i,j
     end type t

     interface assignment (=)
             procedure i_to_t
     end interface

     contains 

     elemental subroutine i_to_t (p, q)

     type(t), intent(out) :: p
     integer, intent(in)  :: q

     p%i = q

     end subroutine

     end module

     use m

     type(t), target :: a(3)
     type(t), target  :: b(3)

     type(t), dimension(:), pointer :: p
     logical :: l(3)

     a%i = 1
     a%j = 2
     b%i = 3
     b%j = 4

     p => b
     l = .true.


     where (l)
          a = p%i
     end where

     print *, a%j

     end

The output I get is:
       32758       32758           0
instead of:
           2           2           2


The problem is that we create a temporary for the defined assignment, but we
don't copy the values of the lhs (before calling the function) to it as they
will be overwritten by the rhs's ones. However, if the assignment function
doesn't set all the members of the derived type, the unset members keep the
values of the temporary, and are copied to the lhs. 
Thus, confirmed


-- 

mikael at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |wrong-code
   Last reconfirmed|0000-00-00 00:00:00         |2009-01-18 20:40:05
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38863