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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/113072] `(a ^ CST0) & (~a ^ CST0)` is not optimized to 0 at the gimple level
Date: Mon, 18 Dec 2023 19:03:45 +0000	[thread overview]
Message-ID: <bug-113072-4-SpVx6i2YTR@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-113072-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113072

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Wait this part is wrong `which does basically `(a ^ 4) & (a ^ (~4))` -> `(4 ^
(~4)) & (a ^ a)` which is 0 as `a ^ a` is 0.`

Anyways a pattern like:
```
(simplify
 (bit_and (bit_xor @0 @1) (bit_xor @0 @2))
 (with { bool wascmp; }
  (if (bitwise_inverted_equal_p (@1, @2, &wascmp))
   { wascmp ? constant_boolean_node (false, type) : build_zero_cst (type); })))
```

Is needed for bool.

  reply	other threads:[~2023-12-18 19:03 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-18 18:53 [Bug tree-optimization/113072] New: " pinskia at gcc dot gnu.org
2023-12-18 19:03 ` pinskia at gcc dot gnu.org [this message]
2023-12-18 19:03 ` [Bug tree-optimization/113072] " pinskia at gcc dot gnu.org
2023-12-18 19:09 ` pinskia at gcc dot gnu.org
2023-12-18 19:10 ` pinskia at gcc dot gnu.org
2023-12-18 19:40 ` pinskia at gcc dot gnu.org
2024-01-01  0:33 ` pinskia at gcc dot gnu.org

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