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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/110252] [14 Regression] Wrong code at -O2/3/s on x86_64-linux-gnu
Date: Wed, 14 Jun 2023 16:13:44 +0000 [thread overview]
Message-ID: <bug-110252-4-xboG8Z8MBw@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-110252-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110252
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2023-06-14
Component|c |tree-optimization
Status|UNCONFIRMED |ASSIGNED
Summary|Wrong code at -O2/3/s on |[14 Regression] Wrong code
|x86_64-linux-gnu |at -O2/3/s on
| |x86_64-linux-gnu
Target Milestone|--- |14.0
Keywords| |wrong-code
Ever confirmed|0 |1
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So phiopt does this:
phiopt match-simplify trying:
_4 >= 0 ? iftmp.0_16 : 1
Matching expression match.pd:1990, gimple-match-5.cc:23
Matching expression match.pd:1990, gimple-match-5.cc:23
Applying pattern match.pd:5283, gimple-match-2.cc:942
Applying pattern match.pd:1378, gimple-match-2.cc:7699
Applying pattern match.pd:1885, gimple-match-3.cc:2770
Applying pattern match.pd:4745, gimple-match-7.cc:15371
Folded into the sequence:
_22 = _4 >= 0;
_21 = (int) _22;
_23 = _4 < 0;
_24 = (int) _23;
_25 = iftmp.0_16 | _24;
statement un-sinked:
iftmp.0_16 = _4 >> 6;
The problem is `_4 >> 6` only has a [0,1] range iff `_4 < 0`.
I have to think of a way of fixing this without too much trouble. Maybe
reverting the patch might be the best for now. But there could be other issues
dealing with phiopt and match-and-simplify later on for a similar reasons ...
next prev parent reply other threads:[~2023-06-14 16:13 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-14 14:52 [Bug c/110252] New: " shaohua.li at inf dot ethz.ch
2023-06-14 16:13 ` pinskia at gcc dot gnu.org [this message]
2023-06-14 21:09 ` [Bug tree-optimization/110252] [14 Regression] " pinskia at gcc dot gnu.org
2023-06-15 2:13 ` pinskia at gcc dot gnu.org
2023-06-15 3:11 ` pinskia at gcc dot gnu.org
2023-06-15 6:22 ` rguenth at gcc dot gnu.org
2023-06-15 6:22 ` rguenth at gcc dot gnu.org
2023-06-21 22:51 ` pinskia at gcc dot gnu.org
2023-06-22 15:36 ` pinskia at gcc dot gnu.org
2023-06-28 20:31 ` pinskia at gcc dot gnu.org
2023-06-28 20:35 ` pinskia at gcc dot gnu.org
2023-06-29 9:22 ` zhendong.su at inf dot ethz.ch
2023-06-29 15:42 ` pinskia at gcc dot gnu.org
2023-06-30 5:18 ` pinskia at gcc dot gnu.org
2023-07-03 11:31 ` pinskia at gcc dot gnu.org
2023-07-06 6:12 ` pinskia at gcc dot gnu.org
2023-07-08 17:16 ` pinskia at gcc dot gnu.org
2023-07-15 3:21 ` pinskia at gcc dot gnu.org
2023-07-19 7:41 ` pinskia at gcc dot gnu.org
2023-07-19 16:19 ` cvs-commit at gcc dot gnu.org
2023-07-19 16:19 ` pinskia at gcc dot gnu.org
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