8242453: [lworld] C2 compilation fails with assert 'correct memory chain'

[TobiHartmann]

Relax the assert in MemNode::optimize_memory_chain because loads from a non-flat array can be pushed through an arraycopy from a flat array (see LoadNode::can_see_arraycopy_value) and end up with an inconsistent memory input (oop load from flat array). The checks emitted for the arraycopy will catch this and the load will be removed but optimize_memory_chain() can still be executed before that happens.

Other options to fix this will be evaluated with JDK-8251039.

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Progress

• Change must not contain extraneous whitespace

Issue

• JDK-8242453: [lworld] C2 compilation fails with assert "correct memory chain" ⚠️ Title mismatch between PR and JBS.

Download

$ git fetch https://git.openjdk.java.net/valhalla pull/134/head:pull/134
$ git checkout pull/134

[bridgekeeper]

👋 Welcome back thartmann! A progress list of the required criteria for merging this PR into lworld will be added to the body of your pull request.

[openjdk]

@TobiHartmann This change now passes all automated pre-integration checks, type /integrate in a new comment to proceed. After integration, the commit message will be:

8242453: [lworld] C2 compilation fails with assert 'correct memory chain'

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Since the source branch of this PR was last updated there have been 3 commits pushed to the lworld branch:

• ef1a221: 8250962: [lworld] C2 should not replace redundant scalar replaceable allocations
• e473d9d: 8244315: [lworld] The hierarchy between V$ref and V$val must be sealed
• 5305fbd: 8244314: [lworld] V.ref and V.val are supposed to be nest mates

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid automatic rebasing, please merge lworld into your branch, and then specify the current head hash when integrating, like this: /integrate ef1a221fb9d2b18a907b98da83744c8ccc681a81.

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

[mlbridge]

Webrevs

• 00: Full (ec73f68)

[TobiHartmann]

/integrate

[openjdk]

@TobiHartmann The following commits have been pushed to lworld since your change was applied:

• ef1a221: 8250962: [lworld] C2 should not replace redundant scalar replaceable allocations
• e473d9d: 8244315: [lworld] The hierarchy between V$ref and V$val must be sealed
• 5305fbd: 8244314: [lworld] V.ref and V.val are supposed to be nest mates

Your commit was automatically rebased without conflicts.

Pushed as commit 448aaa0.