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* [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer
@ 2022-01-12 17:47 michelemartone at users dot sourceforge.net
2022-01-12 17:59 ` [Bug tree-optimization/103995] " michelemartone at users dot sourceforge.net
` (8 more replies)
0 siblings, 9 replies; 10+ messages in thread
From: michelemartone at users dot sourceforge.net @ 2022-01-12 17:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103995
Bug ID: 103995
Summary: conj() ignored with tree loop vectorizer
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: michelemartone at users dot sourceforge.net
Target Milestone: ---
Created attachment 52173
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52173&action=edit
conj() ignored with tree loop vectorizer -- reproducer
Hi.
With gcc-11.2.0 on x86-64 and given certain flags, this program (see
attachment) computes wrong results.
Specifically, it seems like a conj() is being ignored in a loop.
The buggy.c file contains the impacted function, but also a reference one;
their results are being compared in main.c.
Reproduces on arch x86-64 with 11.2.0 with:
gcc -c -O3 buggy.c && gcc -c -O0 main.c && gcc buggy.o main.o -o buggy
&& ./buggy
Using ASAN:
gcc -c -O3 -fsanitize=address -fno-omit-frame-pointer buggy.c && gcc -c
-O3 -fsanitize=address -fno-omit-frame-pointer main.c && gcc buggy.o -lasan
main.o -o buggy && ./buggy
it does not reproduce.
Reproducer flags with lower optimization are:
gcc -c -O1 -ftree-loop-vectorize -ftree-slp-vectorize buggy.c && gcc -c
-O0 main.c && gcc -O0 buggy.o main.o -o buggy && ./buggy
This can be minimized further by deactivating the individual -O1 flags listed
on
https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gcc/Optimize-Options.html#index-ftree-dse
using (-fno-...), exception made for two flags: -ftree-ch and -ftree-forwprop.
Using:
-O0 -ftree-ch -ftree-forwprop -ftree-loop-vectorize
-ftree-slp-vectorize
is not enough -- seems like some implicit -O1 option is needed.
Putting all the code in one file does not reproduce the problem.
The Makefile has a recipe building and running the program with decreasing
optimization level, stepwise.
make # will print BUG on mismatch, OK otherwise; make expected NOT to
fail on gcc-11.2.0
make dist # zip the whole
make clean # clean
It does not reproduce on x86-64 and 10.2.0.
On aarch64 tried only with 11.0.0 and it does not reproduce.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/103995] conj() ignored with tree loop vectorizer
2022-01-12 17:47 [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer michelemartone at users dot sourceforge.net
@ 2022-01-12 17:59 ` michelemartone at users dot sourceforge.net
2022-01-12 19:17 ` [Bug tree-optimization/103995] [11/12 Regression] " pinskia at gcc dot gnu.org
` (7 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: michelemartone at users dot sourceforge.net @ 2022-01-12 17:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103995
--- Comment #1 from Michele Martone <michelemartone at users dot sourceforge.net> ---
Small correction: the URL in the link above should have been just
https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gcc/Optimize-Options.html
(top of the page).
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/103995] [11/12 Regression] conj() ignored with tree loop vectorizer
2022-01-12 17:47 [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer michelemartone at users dot sourceforge.net
2022-01-12 17:59 ` [Bug tree-optimization/103995] " michelemartone at users dot sourceforge.net
@ 2022-01-12 19:17 ` pinskia at gcc dot gnu.org
2022-01-12 22:12 ` michelemartone at users dot sourceforge.net
` (6 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-01-12 19:17 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103995
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|conj() ignored with tree |[11/12 Regression] conj()
|loop vectorizer |ignored with tree loop
| |vectorizer
Target| |x86-64
Target Milestone|--- |11.3
Known to work| |10.2.0
Known to fail| |11.2.0
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/103995] [11/12 Regression] conj() ignored with tree loop vectorizer
2022-01-12 17:47 [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer michelemartone at users dot sourceforge.net
2022-01-12 17:59 ` [Bug tree-optimization/103995] " michelemartone at users dot sourceforge.net
2022-01-12 19:17 ` [Bug tree-optimization/103995] [11/12 Regression] " pinskia at gcc dot gnu.org
@ 2022-01-12 22:12 ` michelemartone at users dot sourceforge.net
2022-01-12 22:13 ` michelemartone at users dot sourceforge.net
` (5 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: michelemartone at users dot sourceforge.net @ 2022-01-12 22:12 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103995
--- Comment #2 from Michele Martone <michelemartone at users dot sourceforge.net> ---
Created attachment 52175
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52175&action=edit
output by running 'make'
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/103995] [11/12 Regression] conj() ignored with tree loop vectorizer
2022-01-12 17:47 [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer michelemartone at users dot sourceforge.net
` (2 preceding siblings ...)
2022-01-12 22:12 ` michelemartone at users dot sourceforge.net
@ 2022-01-12 22:13 ` michelemartone at users dot sourceforge.net
2022-01-13 8:05 ` rguenth at gcc dot gnu.org
` (4 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: michelemartone at users dot sourceforge.net @ 2022-01-12 22:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103995
--- Comment #3 from Michele Martone <michelemartone at users dot sourceforge.net> ---
Comment on attachment 52175
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52175
output by running 'make'
For reference, I add here the output of 'make' with the defect.
The program is being built and run with different flags (also clang, for
comparison).
Each run ends with a line beginning either with 'OK' or 'BUG'.
One can see in the 'BUG' cases, '(0 -12)' is being computed in place of '(12
0)'.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/103995] [11/12 Regression] conj() ignored with tree loop vectorizer
2022-01-12 17:47 [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer michelemartone at users dot sourceforge.net
` (3 preceding siblings ...)
2022-01-12 22:13 ` michelemartone at users dot sourceforge.net
@ 2022-01-13 8:05 ` rguenth at gcc dot gnu.org
2022-01-13 9:15 ` marxin at gcc dot gnu.org
` (3 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-01-13 8:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103995
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2022-01-13
Keywords| |needs-bisection
CC| |marxin at gcc dot gnu.org,
| |rguenth at gcc dot gnu.org,
| |tnfchris at gcc dot gnu.org
Blocks| |53947
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed on the GCC 11 branch head, I suspect it's something to do with SLP
patterns and I cannot reproduce with recent GCC 12.
Tamar, are there any fixes that need backporting in this area?
Martin, can you bisect what fixed it on trunk?
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/103995] [11/12 Regression] conj() ignored with tree loop vectorizer
2022-01-12 17:47 [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer michelemartone at users dot sourceforge.net
` (4 preceding siblings ...)
2022-01-13 8:05 ` rguenth at gcc dot gnu.org
@ 2022-01-13 9:15 ` marxin at gcc dot gnu.org
2022-01-13 10:04 ` rguenth at gcc dot gnu.org
` (2 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: marxin at gcc dot gnu.org @ 2022-01-13 9:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103995
Martin Liška <marxin at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords|needs-bisection |
--- Comment #5 from Martin Liška <marxin at gcc dot gnu.org> ---
Fixed on master with r12-2573-g3c91efec15af4f92.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/103995] [11/12 Regression] conj() ignored with tree loop vectorizer
2022-01-12 17:47 [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer michelemartone at users dot sourceforge.net
` (5 preceding siblings ...)
2022-01-13 9:15 ` marxin at gcc dot gnu.org
@ 2022-01-13 10:04 ` rguenth at gcc dot gnu.org
2022-01-13 10:54 ` cvs-commit at gcc dot gnu.org
2022-01-13 10:54 ` rguenth at gcc dot gnu.org
8 siblings, 0 replies; 10+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-01-13 10:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103995
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot gnu.org
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Mine then.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/103995] [11/12 Regression] conj() ignored with tree loop vectorizer
2022-01-12 17:47 [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer michelemartone at users dot sourceforge.net
` (6 preceding siblings ...)
2022-01-13 10:04 ` rguenth at gcc dot gnu.org
@ 2022-01-13 10:54 ` cvs-commit at gcc dot gnu.org
2022-01-13 10:54 ` rguenth at gcc dot gnu.org
8 siblings, 0 replies; 10+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-01-13 10:54 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103995
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:
https://gcc.gnu.org/g:7f49f50f756c06f4093358ff77c11152777fff1c
commit r11-9458-g7f49f50f756c06f4093358ff77c11152777fff1c
Author: Richard Biener <rguenther@suse.de>
Date: Wed Jul 28 15:12:00 2021 +0200
tree-optimization/101615 - SLP permute opt with CTOR roots
CTOR roots are not explicitely represented so we have to make sure
to materialize permutes on SLP graph entries to them.
2021-07-28 Richard Biener <rguenther@suse.de>
PR tree-optimization/101615
PR tree-optimization/103995
* tree-vect-slp.c (vect_optimize_slp): Materialize permutes
at CTOR SLP graph entries.
* gcc.dg/vect/bb-slp-pr101615-2.c: New testcase.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug tree-optimization/103995] [11/12 Regression] conj() ignored with tree loop vectorizer
2022-01-12 17:47 [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer michelemartone at users dot sourceforge.net
` (7 preceding siblings ...)
2022-01-13 10:54 ` cvs-commit at gcc dot gnu.org
@ 2022-01-13 10:54 ` rguenth at gcc dot gnu.org
8 siblings, 0 replies; 10+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-01-13 10:54 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103995
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|ASSIGNED |RESOLVED
Known to work| |12.0
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
In my testing this fixed it on the branch.
^ permalink raw reply [flat|nested] 10+ messages in thread
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2022-01-12 17:47 [Bug tree-optimization/103995] New: conj() ignored with tree loop vectorizer michelemartone at users dot sourceforge.net
2022-01-12 17:59 ` [Bug tree-optimization/103995] " michelemartone at users dot sourceforge.net
2022-01-12 19:17 ` [Bug tree-optimization/103995] [11/12 Regression] " pinskia at gcc dot gnu.org
2022-01-12 22:12 ` michelemartone at users dot sourceforge.net
2022-01-12 22:13 ` michelemartone at users dot sourceforge.net
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