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References: <bug-30404-12313@http.gcc.gnu.org/bugzilla/>
Subject: [Bug fortran/30404] Wrong FORALL result
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------- Comment #1 from pault at gcc dot gnu dot org  2007-01-08 11:23 -------
There appears to be a double problem here; the segfault, which I can reproduce
by adding more statements in the forall block that sets a, and the incorrect
rendering of the mask logic, according to where the masking is applied.

The program below illustrates the problem more simply.

I have cc'd Roger Sayle.

Paul

  integer, dimension (3, 3) :: a, b, c
  logical, dimension (3,3) :: l1 = .FALSE.
  integer :: i, j

  a = 2
  a (1,1) = 1
  a (3,3) = 1
  a (2,1) = 3
  a (2,3) = 3

  b = a
  c = a

  forall (i = 1:3, a(i, 1) == 1)     ! mask true for i = 1
    forall (j = 1:3, a(2, j) == 3)   ! mask true for j = 1,3
      b (i, j) = 99                  ! set for (i = 1) && (j = 1,3)
      l1 (i, j) = .TRUE.
    end forall
  end forall

   forall (i = 1:3, a(i, 1) .lt. 1000)
    forall (j = 1:3, l1(i, j))       ! mask true for (i = 1) && (j = 1,3)
      c (i, j) = 99                  ! SHOULD be set for (i = 1) && (j = 1,3)
    end forall
  end forall

!  forall (i = 1:3) !                 this segfaults
   forall (i = 1:3, a(i, 1) .lt. 1000)
    forall (j = 1:3, &
 (a(i, 1) == 1 .and. a(2, j) == 3))  ! mask true for (i = 1) && (j = 1,3)
      a (i, j) = 99                  ! SHOULD be set for (i = 1) && (j = 1,3)
    end forall
  end forall

  print *, a                         ! a remains unchanged for gfortran
  print *, b                         ! b is changed correctly
  print *, c                         ! c(2,:) == 99 *sigh*

! Other compilers end up with a == b == c
end


-- 

pault at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sayle at gcc dot gnu dot org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2007-01-08 11:23:23
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30404