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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/88280] missing folding of logical and bitwise AND
Date: Thu, 12 Oct 2023 17:16:40 +0000	[thread overview]
Message-ID: <bug-88280-4-fNmTjHKfyS@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-88280-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88280

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot gnu.org

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Match pattern:
```
(for cmp (eq      ne     )
     bop (bit_ior bit_and)
 (bop:c (cmp @0 integer_zerop) (cmp@2 (bit_and:c @0 @1) integer_zerop))
 @2)
```

testcase that shows the issue (of the swapped order of the ifs)
```
_Bool f0(int a, int b)
{
  if (a == 0) return 1;
  return (a & b) == 0; // (a==0) | ((a &b) == 0) -> ((a &b) == 0)
}

_Bool f0_(int a, int b)
{
  if ((a & b) == 0) return 1;
  return a == 0; // ((a &b) == 0) | (a==0)  -> ((a &b) == 0)
}

_Bool f1(int a, int b)
{
  if (a != 0)  return  (a & b) != 0;
  return 0; // (a!=0) & ((a & b) != 0) -> ((a & b) != 0)
}

_Bool f1_(int a, int b)
{
  if ((a & b) != 0)  return a  != 0;
  return 0; // ((a & b) != 0) & (a!=0) -> ((a & b) != 0)
}
```

      parent reply	other threads:[~2023-10-12 17:16 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-88280-4@http.gcc.gnu.org/bugzilla/>
2023-05-06 18:56 ` pinskia at gcc dot gnu.org
2023-10-12 17:16 ` pinskia at gcc dot gnu.org [this message]

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