8253353: Crash in C2: guarantee(n != NULL) failed: No Node

[vnkozlov]

Nesting loops for this case reaches 400+. But the type of IdeaLoopTree::_nest field is uint8 (the maximum value allowed is 255). The test passed with the following fix proposed by @RealFYang:

- uint8_t _nest; // Nesting depth 
+ uint16_t _nest; // Nesting depth

I think increase size to unsigned short (16 bits) is enough for this value. We will bailout C2 compilation due to big IR graph (MaxNodeLimit = 80000) before we can construct MAX_USHORT (65535) nested loops. And I added asserts to catch such case if it happens.

New regression test is added.
Passed hs-tier1 - 3 testing.

---

Progress

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Issue

• JDK-8253353: Crash in C2: guarantee(n != NULL) failed: No Node

Reviewers

• Vladimir Ivanov (@iwanowww - Reviewer)
• Nils Eliasson (@neliasso - Reviewer)

Contributors

• Fei Yang <fyang@openjdk.org>

Download

$ git fetch https://git.openjdk.java.net/jdk16 pull/135/head:pull/135
$ git checkout pull/135

[bridgekeeper]

👋 Welcome back kvn! 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.

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[vnkozlov]

/contributor add felix.yang@huawei.com

[openjdk]

@vnkozlov Could not parse felix.yang@huawei.com as a valid contributor.
Syntax: /contributor (add|remove) [@user | openjdk-user | Full Name <email@address>]. For example:

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[vnkozlov]

/contributor add fyang

[openjdk]

@vnkozlov
Contributor Fei Yang <fyang@openjdk.org> successfully added.

[mlbridge]

Webrevs

• 00: Full (3d0126f)

[iwanowww]

Looks good.

[openjdk]

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

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

8253353: Crash in C2: guarantee(n != NULL) failed: No Node

Co-authored-by: Fei Yang <fyang@openjdk.org>
Reviewed-by: vlivanov, neliasso

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[neliasso]

Looks good.

[vnkozlov]

/test

[vnkozlov]

/integrate

[openjdk]

@vnkozlov Since your change was applied there has been 1 commit pushed to the master branch:

• e68eac9: 8259765: ZGC: Handle incorrect processor id reported by the operating system

Your commit was automatically rebased without conflicts.

Pushed as commit 1926765.

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