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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/105903] Missed optimization for __synth3way
Date: Wed, 08 Jun 2022 23:53:22 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105903

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |tree-optimization
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
           Severity|normal                      |enhancement
   Last reconfirmed|                            |2022-06-08
           Keywords|                            |missed-optimization

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
Currently we have inside phiopt4
  if (_5 < _6)
    goto <bb 4>; [50.00%]
  else
    goto <bb 3>; [50.00%]

  <bb 3> [local count: 536870913]:
  _9 =3D _5 > _6;

  <bb 4> [local count: 1073741824]:
  # prephitmp_10 =3D PHI <0(2), _9(3)>

That is:
(_5 < _6) ? 0 : (_5 > _6)

Which I think can be optimized to just:
(_5 > _6)=