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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/94892] (x >> 31) + 1 not getting narrowed to
 compare
Date: Wed, 15 Dec 2021 00:31:12 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94892

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Two things we should simplify:
  _4 =3D _3 >> 31;
  _4 !=3D -1

Into:
  _3 >=3D 0 (if _3 is signed, otherwise false)

(this will solve f0)


And:
  _4 =3D x_3(D) >> 31;
  _7 =3D -x_3(D);
  _8 =3D (unsigned int) _7;
  _9 =3D _8 >> 31;
  _10 =3D (int) _9;
  _11 =3D _4 | _10;

Into:
_4 =3D x_3(D) >> 31; // keep around
_t =3D _4 | 1;
_11 =3D x !=3D 0 ? _t : 0;=