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From: "amacleod at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/106379] DCE depends on order
Date: Mon, 08 Aug 2022 20:36:47 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106379

--- Comment #4 from Andrew Macleod <amacleod at redhat dot com> ---
Ranger actually appears to handle both cases the same.  VRP1 gets it whilst
ranger does not.  I believe this to be because we are match and simplifying=
=20

  _1 =3D ~c_5(D);
  _2 =3D _1 & s_4(D);

with c_5 =3D=3D s_4... but at this point, the simplification code doesn't
understand the relation oracle, so I beleive it to be missing the fact that=
 _2
will evaluate to 0 because it doesnt see the equivalency. VRP1 gets it beca=
use
its in intergrated in the legacy range that passed in as an equivset.

I will shortly get to some equivalency processing during simplificatoin as a
part of trying to remove VRP1.  We should then pick this up with in EVRP.=