8366879: [lworld] C2's lock elimination fails after JDK-8335256

[TobiHartmann]

Since JDK-8335256 / #1447 we attempt lock elimination already before Escape Analysis. However, allocations of locked objects might block lock elimination if their escape state isn't determined yet and we only got one chance at eliminating the lock:

valhalla/src/hotspot/share/opto/macro.cpp

Lines 3001 to 3004 in 1207841

	// After coarsened locks are eliminated locking regions
	// become unbalanced. We should not execute any more
	// locks elimination optimizations on them.
	C->mark_unbalanced_boxes();

I changed the code such that we only attempt lock elimination after EA and added a corresponding regression test.

Thanks,
Tobias

---

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Issue

• JDK-8366879: [lworld] C2's lock elimination fails after JDK-8335256 (Bug - P3)

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8366879: [lworld] C2's lock elimination fails after JDK-8335256

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[TobiHartmann]

/integrate

[openjdk]

Going to push as commit 858be30.
Since your change was applied there have been 2 commits pushed to the lworld branch:

• 2fddd34: 8366913: [lworld] Add ACC_STRICT_INIT to ClassFile
• 59ffa2d: 8366267: [lworld] Injected ACC_IDENTITY escapes to instrumentation of older classes

Your commit was automatically rebased without conflicts.

[openjdk]

@TobiHartmann Pushed as commit 858be30.

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