[Bug tree-optimization/32378] can't determine dependence (distinct sections of an array)

["dorit at il dot ibm dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #4 from dorit at il dot ibm dot com  2007-06-18 11:08 -------
I see this in the vectorizer dump file (with mainline from a few days ago):

(compute_affine_dependence
  (stmt_a =
D.1423_50 = (*a_49(D))[D.1422_48])
  (stmt_b =
(*a_49(D))[D.1420_51] = D.1425_54)
Data ref a:
(Data Ref:
  stmt: D.1423_50 = (*a_49(D))[D.1422_48];
  ref: (*a_49(D))[D.1422_48];
  base_object: (*a_49(D))[0];
  Access function 0: {pretmp.48_45 + 1, +, 1}_1
  Access function 1: 0B
)
Data ref b:
(Data Ref:
  stmt: (*a_49(D))[D.1420_51] = D.1425_54;
  ref: (*a_49(D))[D.1420_51];
  base_object: (*a_49(D))[0];
  Access function 0: {0, +, 1}_1
  Access function 1: 0B
)
affine dependence test not usable: access function not affine or constant.
(dependence classified: scev_not_known)
)
(compute_affine_dependence
  (stmt_a =
D.1424_53 = (*b_52(D))[D.1420_51])
  (stmt_b =
(*a_49(D))[D.1420_51] = D.1425_54)
)

(the IR looks a bit different than PR32075, but the data-rependence analysis
fails with the same problem). pinskia - are you still planning to address this
issue?


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