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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/77899] incorrect VR_RANGE for a signed char
 function argument
Date: Mon, 06 Sep 2021 11:32:22 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D77899

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-09-06
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot =
gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1

--- Comment #12 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
  p_6 =3D &d[130] + _1;
  if (&MEM <char[260]> [(void *)&d + 2B] > p_6)

Even this should be folded but is not currently:
void f (signed char i)
{
  char d [260];

  const char *p =3D &d[130];

  p +=3D i;

  if (p =3D=3D d + 2 || d + 257 =3D=3D p)
    __builtin_abort ();
}


I am thinking ptr_difference_const is not able to handle &MEM <char[260]>
[(void *)&d + 2B] correctly.=