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From: "martin@mpa-garching.mpg.de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/98544] New: [11 regression] Wrong code generated by tree vectorizer
Date: Tue, 05 Jan 2021 18:50:18 +0000 [thread overview]
Message-ID: <bug-98544-4@http.gcc.gnu.org/bugzilla/> (raw)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98544
Bug ID: 98544
Summary: [11 regression] Wrong code generated by tree
vectorizer
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: martin@mpa-garching.mpg.de
Target Milestone: ---
Created attachment 49893
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49893&action=edit
test case
The attached test case (sorry, I don't have the time to reduce this properly at
the moment ...) tests real-valued FFTs of different lengths and should not
output anything if compiled properly.
However, with current trunk and the following compiler command line, some of
the results are really wrong:
martin@debian:~/codes/ducc/bug$ g++ -std=c++17 -O1 -mavx -ftree-vectorize
bug2.cc
martin@debian:~/codes/ducc/bug$ ./a.out
problem at length 15; discrepancy is 4.40898
problem at length 20; discrepancy is 4.54691
problem at length 21; discrepancy is 3.70442
problem at length 25; discrepancy is 8.40318
problem at length 27; discrepancy is 8.44956
problem at length 28; discrepancy is 3.12203
problem at length 30; discrepancy is 8.81795
The discrepancies should be below 1e-15.
The failure goes away when removing either "-ftree-vectorize" or "-mavx". On
released versions of gcc, it runs fine.
next reply other threads:[~2021-01-05 18:50 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-05 18:50 martin@mpa-garching.mpg.de [this message]
2021-01-05 19:36 ` [Bug tree-optimization/98544] " martin@mpa-garching.mpg.de
2021-01-06 6:00 ` marxin at gcc dot gnu.org
2021-01-06 6:03 ` [Bug tree-optimization/98544] [11 regression] Wrong code generated by tree vectorizer since r11-3917-g28290cb50c7dbf87 marxin at gcc dot gnu.org
2021-01-06 9:02 ` rguenth at gcc dot gnu.org
2021-01-07 13:59 ` rguenth at gcc dot gnu.org
2021-01-07 14:26 ` marxin at gcc dot gnu.org
2021-01-07 14:27 ` rguenth at gcc dot gnu.org
2021-01-07 14:35 ` rguenth at gcc dot gnu.org
2021-01-07 15:01 ` rguenth at gcc dot gnu.org
2021-01-07 15:05 ` rguenth at gcc dot gnu.org
2021-01-07 15:19 ` rguenth at gcc dot gnu.org
2021-01-07 15:29 ` rguenth at gcc dot gnu.org
2021-01-07 15:37 ` martin@mpa-garching.mpg.de
2021-01-07 15:50 ` rguenth at gcc dot gnu.org
2021-01-07 16:08 ` martin@mpa-garching.mpg.de
2021-01-07 16:48 ` rguenth at gcc dot gnu.org
2021-01-08 12:14 ` rguenth at gcc dot gnu.org
2021-01-08 12:16 ` rguenth at gcc dot gnu.org
2021-01-08 12:20 ` marxin at gcc dot gnu.org
2021-01-08 13:09 ` cvs-commit at gcc dot gnu.org
2021-01-08 13:09 ` rguenth at gcc dot gnu.org
2021-01-08 14:07 ` martin@mpa-garching.mpg.de
2021-01-08 14:18 ` rguenther at suse dot de
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