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From: "xry111 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/112457] Possible better vectorization of
 different reduction min/max reduction
Date: Tue, 02 Jan 2024 16:03:38 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D112457

Xi Ruoyao <xry111 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |xry111 at gcc dot gnu.org

--- Comment #4 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
There is also:

double
test (double *p)
{
  double ret =3D p[0];
  for (int i =3D 1; i < 4; i++)
    ret =3D __builtin_fmin (ret, p[i]);
  return ret;
}

This is not vectorized.

And

double
test (double *p)
{
  double ret =3D __builtin_inf(); /* or __builtin_nan("") */
  for (int i =3D 0; i < 4; i++)
    ret =3D __builtin_fmin (ret, p[i]);
  return ret;
}

is compiled to:

  _16 =3D .REDUC_FMIN (vect__4.7_17);
  _22 =3D .REDUC_FMIN ({  Inf,  Inf,  Inf,  Inf });=20
  _20 =3D .FMIN (_16, _22); [tail call]
  return _20;

So there is an redundant .FMIN operation.=