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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/95185] Failure to optimize specific kind of sign comparison check
Date: Mon, 28 Aug 2023 21:08:01 +0000	[thread overview]
Message-ID: <bug-95185-4-F4waJzm4rr@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-95185-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95185

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

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

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #5)
> 
> Something like:
> Prefer ^ over ==
> ```
> (for cmp
> (for cmpN
> (for neeq
>  (simplify
>   (neeq:c (cmp @0 @1) @3
>   (if (cmpN == inverseof(cmp, TREE_TYPE (type))
>    (bit_xor (cmpN @0 @1) @3)
>   )
>  )
> )))
> ```

Actually we can just do:
```
/* For CMP == b, prefer CMP` ^ b. */
(for neeq (ne eq)
 (for cmp (tcc_comparison)
  (simplify
   (neeq:c (cmp@0 @1 @2) @3)
   (bit_xor (bit_not! @0) @3)
  )
 )
)
```
Since we already have folding of (bit_not cmp) in another place.

  parent reply	other threads:[~2023-08-28 21:08 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-18 12:05 [Bug tree-optimization/95185] New: " gabravier at gmail dot com
2020-05-18 13:15 ` [Bug tree-optimization/95185] " rguenth at gcc dot gnu.org
2020-05-18 13:16 ` rguenth at gcc dot gnu.org
2021-10-04 23:02 ` arjun.is at lostca dot se
2021-10-04 23:12 ` pinskia at gcc dot gnu.org
2023-06-18 19:24 ` pinskia at gcc dot gnu.org
2023-08-28 20:36 ` pinskia at gcc dot gnu.org
2023-08-28 21:08 ` pinskia at gcc dot gnu.org [this message]
2023-08-29  4:04 ` pinskia at gcc dot gnu.org
2023-09-11 22:14 ` [Bug tree-optimization/95185] [11/12/13/14 Regression] " pinskia at gcc dot gnu.org
2024-03-22 14:09 ` law at gcc dot gnu.org

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