8293996: C2: fix and simplify IdealLoopTree::do_remove_empty_loop

[GoeLin]

I backport this for parity with 11.0.19-oracle.

Resolved Copyright in test file, will mark as clean.

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Progress

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Issue

• JDK-8293996: C2: fix and simplify IdealLoopTree::do_remove_empty_loop

Reviewing

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[bridgekeeper]

👋 Welcome back goetz! 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]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 02: Full - Incremental (6bc61143)
• 01: Full - Incremental (3cfeeb57)
• 00: Full (eb9d3f05)

[openjdk]

@GoeLin Please do not rebase or force-push to an active PR as it invalidates existing review comments. Note for future reference, the bots always squash all changes into a single commit automatically as part of the integration. See OpenJDK Developers’ Guide for more information.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[openjdk]

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

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

8293996: C2: fix and simplify IdealLoopTree::do_remove_empty_loop

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[GoeLin]

Pre-submit failure: Windows build failed. I can not see why. The nightly SAP Win build passed. I restarted the Pre-submit tests to be sure.

[GoeLin]

/integrate

[openjdk]

Going to push as commit 369dedb.
Since your change was applied there have been 9 commits pushed to the master branch:

• 80eecc5: 8299439: java/text/Format/NumberFormat/CurrencyFormat.java fails for hr_HR
• dfcf7c1: 8256111: Create implementation for NSAccessibilityStaticText protocol
• 06f769a: 8292863: assert(_print_inlining_stream->size() > 0) failed: missing inlining msg
• 1d78ce4: 8221351: Crash in KlassFactory::check_shared_class_file_load_hook
• 3c2763f: 8195716: BootstrapLoggerTest : Executor still alive
• decfc86: 8217353: java/util/logging/LogManager/Configuration/updateConfiguration/HandlersOnComplexResetUpdate.java fails with Unexpected reference: java.lang.ref.WeakReference
• dc5590f: 8213932: [TESTBUG] assertEquals is invoked with the arguments in the wrong order
• 1713cf1: 8215759: [test] java/math/BigInteger/ModPow.java can throw an ArithmeticException
• 13eadde: 8215372: test/jdk/java/nio/file/DirectoryStream/Basic.java not correct when using a glob

Your commit was automatically rebased without conflicts.

[openjdk]

@GoeLin Pushed as commit 369dedb.

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