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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/108354] [13 Regression] Dead Code Elimination Regression at -O2 since r13-89-gb3e98eb3396e16
Date: Tue, 31 Jan 2023 04:33:44 +0000 [thread overview]
Message-ID: <bug-108354-4-ZqpJ9nZTQ5@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108354-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108354
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
Depends on| |96921
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Looks like:
_4 = (int) _2;
...
i.1_15 = (unsigned short) _2;
_16 = 1 - i.1_15;
_6 = (int) _16;
...
_8 = _4 | _6;
Simplify to just
_4 = (int) _2;
...
_t = _2 ^ 1;
_6 = (int)_t;
...
_8 = _4 | _6;
Which then simplifies down to:
_8 = 1; (because (_2 ^ 1) | (_2) == 1)
Which then would be optimized.
Let me look.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96921
[Bug 96921] Failure to optimize combined boolean not patterns
next prev parent reply other threads:[~2023-01-31 4:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-10 12:41 [Bug tree-optimization/108354] New: Dead Code Elimination Regression at -O2 (trunk vs. 12.2.0) yann at ywg dot ch
2023-01-10 14:44 ` [Bug tree-optimization/108354] [13 Regression] Dead Code Elimination Regression at -O2 since r13-89-gb3e98eb3396e16 marxin at gcc dot gnu.org
2023-01-31 4:33 ` pinskia at gcc dot gnu.org [this message]
2023-01-31 4:52 ` pinskia at gcc dot gnu.org
2023-01-31 8:23 ` pinskia at gcc dot gnu.org
2023-01-31 20:01 ` pinskia at gcc dot gnu.org
2023-01-31 20:06 ` pinskia at gcc dot gnu.org
2023-01-31 20:07 ` pinskia at gcc dot gnu.org
2023-02-14 21:47 ` pinskia at gcc dot gnu.org
2023-02-14 21:48 ` pinskia at gcc dot gnu.org
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