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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/68086] Expression explicitly defined outside
 the loop is moved inside the loop by the optimizer
Date: Tue, 16 May 2023 23:22:14 +0000
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X-Bugzilla-Component: tree-optimization
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D68086

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|rtl-optimization            |tree-optimization

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So we start with:
  <bb 3> :
  _1 =3D (long unsigned int) i_13;
  _2 =3D _1 * 4;
  _3 =3D -_2;
  rebased_15 =3D data_14(D) + _3;
  goto <bb 5>; [INV]

  <bb 4> :
  _4 =3D (long unsigned int) i_10;
  _5 =3D _4 * 4;
  _6 =3D rebased_15 + _5;
  _7 =3D *_6;

And then forwprop turns it into:
  _4 =3D (long unsigned intD.16) i_10;
  _5 =3D _4 * 4;
  _11 =3D _4 - _1;
  _21 =3D _11 * 4;
  _6 =3D data_14(D) + _21;
  # VUSE <.MEM_16(D)>
  _7 =3D *_6;

Except then IVOPT does not know how to handle this correctly.=