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From: "law at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/112545] [14 Regression] Size regression when
 using -Os starting with r14-569-g21e2ef2dc25
Date: Sat, 09 Mar 2024 05:04:46 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D112545

--- Comment #2 from Jeffrey A. Law <law at gcc dot gnu.org> ---
This looks like a missed case for singletons.

  _1 =3D d.9_28 <=3D 0;
  _2 =3D (signed short) _1;
  _3 =3D (signed short) d.9_28;
  c.a =3D 0;
  if (_2 =3D=3D _3)
    goto <bb 4>; [0.00%]
  else
    goto <bb 5>; [100.00%]


Back substituting the condition is:

(d.9_28 <=3D 0) =3D=3D d.9_28

d.9_28 <=3D 0 has a range [0,1]

The only value that can make that expression true is if d.9_28 has the valu=
e 0.=