8254998: C2: assert(!n->as_Loop()->is_transformed_long_loop()) failure with -XX:StressLongCountedLoop=1 #735

rwestrel · 2020-10-19T12:07:46Z

Transformation of a long counted loop into a loop nest with a counted
loop inner loop happens in 2 passes of loop opts: first the loop nest
is created and then the inner loop is transformed into a counted
loop. The assert fires because the second step doesn't have a chance
to run given the first step was executed as the last loop opts pass
before running out of allowed loop opts passes. The fix I propose for
this corner case is to relax the assert to account for this.

Progress

Change must not contain extraneous whitespace
Commit message must refer to an issue
Change must be properly reviewed

Testing

	Linux x64	Windows x64	macOS x64
Build	✔️ (5/5 passed)	✔️ (2/2 passed)	✔️ (2/2 passed)
Test (tier1)	✔️ (9/9 passed)	✔️ (9/9 passed)	✔️ (9/9 passed)

Issue

JDK-8254998: C2: assert(!n->as_Loop()->is_transformed_long_loop()) failure with -XX:StressLongCountedLoop=1

Reviewers

Vladimir Ivanov (@iwanowww - Reviewer) ⚠️ Review applies to 3e6d026
Vladimir Kozlov (@vnkozlov - Reviewer) ⚠️ Review applies to 3e6d026
Tobias Hartmann (@TobiHartmann - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/735/head:pull/735
$ git checkout pull/735

bridgekeeper · 2020-10-19T12:10:43Z

👋 Welcome back roland! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2020-10-19T12:15:31Z

@rwestrel The following label will be automatically applied to this pull request:

hotspot-compiler

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

mlbridge · 2020-10-19T12:18:21Z

Webrevs

01: Full - Incremental (913cd87)
00: Full (3e6d026)

iwanowww

Looks good.

openjdk · 2020-10-19T17:28:47Z

@rwestrel This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8254998: C2: assert(!n->as_Loop()->is_transformed_long_loop()) failure with -XX:StressLongCountedLoop=1

Reviewed-by: vlivanov, kvn, thartmann

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 31 new commits pushed to the master branch:

3f9c8a3: 8254966: Remove unused code from Matcher
21e67e5: 8225790: Two NestedDialogs tests fail on Ubuntu
017d151: 8254842: [JVMCI] copy thread name when attaching libgraal thread to HotSpot
5d1397f: 8254282: Add Linux x86_32 builds to submit workflow
7ba6a6b: 8251158: Implementation of JEP 387: Elastic Metaspace
5fedfa7: 8251271: C2: Compile::_for_igvn list is corrupted after RenumberLiveNodes
98ec4a6: 8254805: compiler/debug/TestStressCM.java is still failing
355f44d: 8254994: [x86] C1 StubAssembler::call_RT, "call_offset might not be initialized"
0a75b37: 8254776: Remove unimplemented LowMemoryDetector::check_memory_usage
b65dcfa: 8197981: Missing return statement in __sync_val_compare_and_swap_8
... and 21 more: https://git.openjdk.java.net/jdk/compare/e76de189561b94b611630a49ebacde67c1512129...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

vnkozlov

Good.

TobiHartmann

Looks good to me.

TobiHartmann · 2020-10-20T05:45:10Z

test/hotspot/jtreg/compiler/longcountedloops/TestTooManyLoopOpts.java

+
+/**
+ * @test
+ * @bug JDK-8254998


I didn't know that the bug ID format with "JDK-" is accepted as well but I would suggest to remove it for consistency with other tests.

I didn't include "JDK-" on purpose. I've just fixed it.

openjdk · 2020-10-20T07:17:37Z

@rwestrel To determine the appropriate audience for reviewing this pull request, one or more labels corresponding to different subsystems will normally be applied automatically. However, no automatic labelling rule matches the changes in this pull request. In order to have an "RFR" email sent to the correct mailing list, you will need to add one or more applicable labels manually using the /label pull request command.

Applicable Labels

2d
awt
beans
build
compiler
core-libs
hotspot
hotspot-compiler
hotspot-gc
hotspot-jfr
hotspot-runtime
i18n
javadoc
jdk
jmx
kulla
net
nio
security
serviceability
shenandoah
sound
swing

rwestrel · 2020-10-20T07:22:22Z

@iwanowww @vnkozlov @TobiHartmann thanks for the review.

openjdk · 2020-10-20T07:27:24Z

@rwestrel This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8254998: C2: assert(!n->as_Loop()->is_transformed_long_loop()) failure with -XX:StressLongCountedLoop=1

Reviewed-by: vlivanov, kvn, thartmann

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 28 new commits pushed to the master branch:

5d1397f: 8254282: Add Linux x86_32 builds to submit workflow
7ba6a6b: 8251158: Implementation of JEP 387: Elastic Metaspace
5fedfa7: 8251271: C2: Compile::_for_igvn list is corrupted after RenumberLiveNodes
98ec4a6: 8254805: compiler/debug/TestStressCM.java is still failing
355f44d: 8254994: [x86] C1 StubAssembler::call_RT, "call_offset might not be initialized"
0a75b37: 8254776: Remove unimplemented LowMemoryDetector::check_memory_usage
b65dcfa: 8197981: Missing return statement in __sync_val_compare_and_swap_8
5b51085: 8254997: Remove unimplemented OSContainer::read_memory_limit_in_bytes
c87cdf7: 8254029: ObjectMonitor cleanup/minor bug-fix changes extracted from JDK-8253064
7a580ca: 8255027: Problem list for Graal test gc/stress/TestStressG1Humongous.java
... and 18 more: https://git.openjdk.java.net/jdk/compare/e76de189561b94b611630a49ebacde67c1512129...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

rwestrel · 2020-10-20T11:50:06Z

/integrate

openjdk · 2020-10-20T11:54:20Z

@rwestrel Since your change was applied there have been 32 commits pushed to the master branch:

3ee0380: 8234393: [macos] printing ignores printer tray
3f9c8a3: 8254966: Remove unused code from Matcher
21e67e5: 8225790: Two NestedDialogs tests fail on Ubuntu
017d151: 8254842: [JVMCI] copy thread name when attaching libgraal thread to HotSpot
5d1397f: 8254282: Add Linux x86_32 builds to submit workflow
7ba6a6b: 8251158: Implementation of JEP 387: Elastic Metaspace
5fedfa7: 8251271: C2: Compile::_for_igvn list is corrupted after RenumberLiveNodes
98ec4a6: 8254805: compiler/debug/TestStressCM.java is still failing
355f44d: 8254994: [x86] C1 StubAssembler::call_RT, "call_offset might not be initialized"
0a75b37: 8254776: Remove unimplemented LowMemoryDetector::check_memory_usage
... and 22 more: https://git.openjdk.java.net/jdk/compare/e76de189561b94b611630a49ebacde67c1512129...master

Your commit was automatically rebased without conflicts.

Pushed as commit 294e070.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

test & fix

3e6d026

openjdk bot added the rfr Pull request is ready for review label Oct 19, 2020

openjdk bot added the hotspot-compiler hotspot-compiler-dev@openjdk.org label Oct 19, 2020

iwanowww approved these changes Oct 19, 2020

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openjdk bot added the ready Pull request is ready to be integrated label Oct 19, 2020

vnkozlov approved these changes Oct 19, 2020

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TobiHartmann approved these changes Oct 20, 2020

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test fix

913cd87

TobiHartmann approved these changes Oct 20, 2020

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openjdk bot closed this Oct 20, 2020

openjdk bot added integrated Pull request has been integrated and removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Oct 20, 2020

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8254998: C2: assert(!n->as_Loop()->is_transformed_long_loop()) failure with -XX:StressLongCountedLoop=1 #735

8254998: C2: assert(!n->as_Loop()->is_transformed_long_loop()) failure with -XX:StressLongCountedLoop=1 #735

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8254998: C2: assert(!n->as_Loop()->is_transformed_long_loop()) failure with -XX:StressLongCountedLoop=1 #735

8254998: C2: assert(!n->as_Loop()->is_transformed_long_loop()) failure with -XX:StressLongCountedLoop=1 #735

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