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* [Bug c++/94953] New: A lot of false maybe-uninitialized warnings with O3
@ 2020-05-05 14:38 olaf.krzikalla at dlr dot de
2020-05-06 6:55 ` [Bug c++/94953] " rguenth at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: olaf.krzikalla at dlr dot de @ 2020-05-05 14:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94953
Bug ID: 94953
Summary: A lot of false maybe-uninitialized warnings with O3
Product: gcc
Version: 9.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: olaf.krzikalla at dlr dot de
Target Milestone: ---
See https://godbolt.org/z/nh2gJ9
The warnings only appear with -O3. They only appear for 7<=Blocksize<=16.
They disappear, if you comment out line 32, which is unrelated to
oldDestinationCache.
I'd like to know what is going on here.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/94953] A lot of false maybe-uninitialized warnings with O3
2020-05-05 14:38 [Bug c++/94953] New: A lot of false maybe-uninitialized warnings with O3 olaf.krzikalla at dlr dot de
@ 2020-05-06 6:55 ` rguenth at gcc dot gnu.org
2020-05-06 14:30 ` olaf.krzikalla at dlr dot de
2021-08-08 5:00 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-05-06 6:55 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94953
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Blocks| |24639
Last reconfirmed| |2020-05-06
Known to fail| |11.0, 9.3.1
Status|UNCONFIRMED |NEW
Keywords| |diagnostic
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed. Can you please attach the testcase?
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=24639
[Bug 24639] [meta-bug] bug to track all Wuninitialized issues
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/94953] A lot of false maybe-uninitialized warnings with O3
2020-05-05 14:38 [Bug c++/94953] New: A lot of false maybe-uninitialized warnings with O3 olaf.krzikalla at dlr dot de
2020-05-06 6:55 ` [Bug c++/94953] " rguenth at gcc dot gnu.org
@ 2020-05-06 14:30 ` olaf.krzikalla at dlr dot de
2021-08-08 5:00 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: olaf.krzikalla at dlr dot de @ 2020-05-06 14:30 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94953
--- Comment #2 from Olaf Krzikalla <olaf.krzikalla at dlr dot de> ---
Created attachment 48469
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48469&action=edit
Test case code triggering the warning
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/94953] A lot of false maybe-uninitialized warnings with O3
2020-05-05 14:38 [Bug c++/94953] New: A lot of false maybe-uninitialized warnings with O3 olaf.krzikalla at dlr dot de
2020-05-06 6:55 ` [Bug c++/94953] " rguenth at gcc dot gnu.org
2020-05-06 14:30 ` olaf.krzikalla at dlr dot de
@ 2021-08-08 5:00 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-08 5:00 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94953
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So there looks like there are two issues.
First warning for each template instantiation.
The second problem is SLP is introducing some uses that was not in the original
IR.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-08-08 5:00 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-05-05 14:38 [Bug c++/94953] New: A lot of false maybe-uninitialized warnings with O3 olaf.krzikalla at dlr dot de
2020-05-06 6:55 ` [Bug c++/94953] " rguenth at gcc dot gnu.org
2020-05-06 14:30 ` olaf.krzikalla at dlr dot de
2021-08-08 5:00 ` pinskia at gcc dot gnu.org
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