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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/94675] [9/10/11/12 regression] -Warray-bounds
 false positive with -O2 since r9-1948
Date: Mon, 06 Sep 2021 11:25:44 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94675

--- Comment #20 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So on the trunk we get:
  c_len.0_1 =3D c_len;
  _2 =3D (long unsigned int) c_len.0_1;
  _6 =3D &c + _2;
  MEM <const void *> [(struct pstream_t *)&ps] =3D &c;
  MEM <const void *> [(struct pstream_t *)&ps + 8B] =3D _6;
  _17 =3D (signed long) c_len.0_1;
  _11 =3D _17;
  _12 =3D (long unsigned int) _11;
  if (_12 > 6)
    goto <bb 3>; [50.00%]
  else
    goto <bb 4>; [50.00%]

  <bb 3> [local count: 483183820]:
  ps.D.4009.s =3D &MEM <byte> [(void *)&c + 7B];

  <bb 4> [local count: 590558005]:


Which is correct, I think the original testcase and the testcase in comment=
 #1
and comment #11 are bogus and incorrect. There is always an out of bounds.=