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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/101009] [12 Regression] wrong code with "-O3
 -fno-tree-sra"
Date: Fri, 11 Jun 2021 06:41:10 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101009

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Hmm, so

(compute_affine_dependence
  stmt_a: g[1].c =3D 1;
  stmt_b: *f.0_1 =3D g[1];
) -> no dependence

isn't the problem but the problem is

(compute_affine_dependence
  stmt_a: g[1].c =3D 1;
  stmt_b: *f.0_1 =3D g[1];
(analyze_overlapping_iterations
  (chrec_a =3D 1)
  (chrec_b =3D 1)
(analyze_ziv_subscript
)
  (overlap_iterations_a =3D [0])
  (overlap_iterations_b =3D [0]))
(build_classic_dist_vector
  dist_vector =3D (  1
  )
)
)

The compute_affine_dependence dumping fails to mark the DR involved, for the
second query it's really g[1].c vs. g[1] but that should have a dist vector
of 0, not 1 I think.=