[Bug target/103771] [12 Regression] Missed vectorization under -mavx512f -mavx512vl after r12-5489

pinskia at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Tue Feb 1 05:21:52 GMT 2022


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103771

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #33 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Oh yes I remember why factor_out_conditional_conversion is not doing it. it is
because we have two bb but the current code does not handle that case.
That is we have:
  if (x.1_1 > 255)
    goto <bb 3>; [INV]
  else
    goto <bb 4>; [INV]

  <bb 3> :
  _2 = -x_5(D);
  _3 = _2 >> 31;
  iftmp.0_7 = (uint8_t) _3;
  goto <bb 5>; [INV]

  <bb 4> :
  iftmp.0_6 = (uint8_t) x_5(D);

  <bb 5> :
  # iftmp.0_4 = PHI <iftmp.0_7(3), iftmp.0_6(4)>

While the correct code only handles the case where the one of the bb4 does not
exist. Yes I am working on this for GCC 13.


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