public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/103037] [11/12 Regression] Wrong code with -O2 since r11-6100-gd41b097350d3c5d0
Date: Tue, 02 Nov 2021 09:08:18 +0000 [thread overview]
Message-ID: <bug-103037-4-fDT7p8rdU5@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-103037-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103037
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
We have:
var_3.2_4 = var_3;
iftmp.1_14 = (int) var_3.2_4;
var_11_lsm.14_8 = _7(D);
<bb 3> [local count: 955630225]:
# RANGE [0, 24] NONZERO 31
# a_20 = PHI <a_18(10), 0(9)>
_19 = MEM <short unsigned int[23]> [(short unsigned int &)&arr_4][a_20];
if (_19 > 1)
goto <bb 5>; [50.00%]
else
goto <bb 4>; [50.00%]
<bb 4> [local count: 477815112]:
# RANGE [0, 1] NONZERO 1
_3 = (int) _19;
if (_19 != 0)
goto <bb 5>; [20.00%]
else
goto <bb 6>; [80.00%]
<bb 5> [local count: 477815112]:
# RANGE [0, 1] NONZERO 1
# _24 = PHI <_3(4), 1(3)>
# RANGE [1, 65535] NONZERO 65535
iftmp.1_15 = (int) _19;
goto <bb 7>; [100.00%]
<bb 6> [local count: 477815112]:
<bb 7> [local count: 955630225]:
# RANGE [-32768, 65535]
# iftmp.1_10 = PHI <iftmp.1_15(5), iftmp.1_14(6)>
# RANGE [0, 1] NONZERO 1
# _25 = PHI <_24(5), 0(6)>
# RANGE [-1, 1]
_5 = _25 / iftmp.1_10;
and seems PRE is trying top simplify 1 / _3 and _3 / _3. _3 has correctly
range of [0, 1] - in that bb _19 can't be anything but 0 or 1 given the
condition, but
iftmp.1_15 = (int) _19; isn't equivalent to that, because it is reachable from
other bbs, even when it is also (int) _19.
So, does PRE need to temporarily reset_flow_sensitive_info in such cases and
restore if it didn't succeed?
next prev parent reply other threads:[~2021-11-02 9:08 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-02 7:17 [Bug tree-optimization/103037] New: [11/12 Regression] Wrong code with -O2 vsevolod.livinskij at frtk dot ru
2021-11-02 7:36 ` [Bug tree-optimization/103037] [11/12 Regression] Wrong code with -O2 since r11-6100-gd41b097350d3c5d0 marxin at gcc dot gnu.org
2021-11-02 7:52 ` pinskia at gcc dot gnu.org
2021-11-02 8:43 ` rguenth at gcc dot gnu.org
2021-11-02 8:51 ` jakub at gcc dot gnu.org
2021-11-02 9:08 ` jakub at gcc dot gnu.org [this message]
2021-11-02 14:18 ` rguenther at suse dot de
2021-11-03 10:08 ` rguenth at gcc dot gnu.org
2021-11-05 13:39 ` rguenth at gcc dot gnu.org
2022-02-23 15:25 ` rguenth at gcc dot gnu.org
2022-02-25 12:21 ` cvs-commit at gcc dot gnu.org
2022-02-25 12:21 ` [Bug tree-optimization/103037] [11 " rguenth at gcc dot gnu.org
2022-04-21 7:50 ` rguenth at gcc dot gnu.org
2023-05-29 10:05 ` jakub at gcc dot gnu.org
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=bug-103037-4-fDT7p8rdU5@http.gcc.gnu.org/bugzilla/ \
--to=gcc-bugzilla@gcc.gnu.org \
--cc=gcc-bugs@gcc.gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).