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Subject: [Bug tree-optimization/32378] can't determine dependence (distinct sections of an array)
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------- Comment #6 from dorit at gcc dot gnu dot org  2007-08-19 13:47 -------
> Sebastian - any thughts/plans?

Here's another testcase:

subroutine sub(aa,bb,n,m)
  implicit none
  integer, intent(in) :: n,m
  real, intent(inout) :: aa(n,m)
  real, intent(in)    :: bb(n,m)
  integer :: i,j
 do j= 2,n
    do i = 1,m
      aa(i,j)= aa(i,j-1)+bb(i,j-1)
    enddo
  enddo
end subroutine
end

Here too we get:

(compute_affine_dependence
  (stmt_a =
D.1385_55 = (*aa_54(D))[D.1384_53])
  (stmt_b =
(*aa_54(D))[D.1380_49] = D.1390_62)
(subscript_dependence_tester
(analyze_overlapping_iterations
  (chrec_a = {pretmp.34_76 + 1, +, 1}_2)
  (chrec_b = {pretmp.34_32 + 1, +, 1}_2)
(analyze_siv_subscript
siv test failed: unimplemented.
)
  (overlap_iterations_a = not known
)
  (overlap_iterations_b = not known
)
)
(dependence classified: scev_not_known)
)
)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32378