8347718: Unexpected NullPointerException in C2 compiled code due to ReduceAllocationMerges

[TobiHartmann]

Hi all,

This pull request contains a backport of commit 9f4d3de4 from the openjdk/jdk repository.

The commit being backported was authored by Cesar Soares Lucas on 28 Jan 2025 and was reviewed by Vladimir Kozlov and Tobias Hartmann.

Thanks!

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8347718 needs maintainer approval

Issue

• JDK-8347718: Unexpected NullPointerException in C2 compiled code due to ReduceAllocationMerges (Bug - P3 - Approved)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk24u.git pull/65/head:pull/65
$ git checkout pull/65

Update a local copy of the PR:
$ git checkout pull/65
$ git pull https://git.openjdk.org/jdk24u.git pull/65/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 65

View PR using the GUI difftool:
$ git pr show -t 65

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk24u/pull/65.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back thartmann! 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]

@TobiHartmann 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:

8347718: Unexpected NullPointerException in C2 compiled code due to ReduceAllocationMerges

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 10 new commits pushed to the master branch:

• 63a800d: 8345590: AIX 'make all' fails after JDK-8339480
• 82ccb07: 8345569: [ubsan] adjustments to filemap.cpp and virtualspace.cpp for macOS aarch64
• bbfe405: 8346881: [ubsan] logSelection.cpp:154:24 / logSelectionList.cpp:72:94 : runtime error: applying non-zero offset 1 to null pointer
• 5a3ab69: 8347576: Error output in libjsound has non matching format strings
• 46b3927: 8343882: BasicAnnoTests doesn't handle multiple annotations at the same position
• a07d784: 8346972: Test java/nio/channels/FileChannel/LoopingTruncate.java fails sometimes with IOException: There is not enough space on the disk
• 687ea73: 8347171: (dc) java/nio/channels/DatagramChannel/InterruptibleOrNot.java fails with virtual thread factory
• 72f23f0: 8349002: GenShen: Deadlock during shutdown
• 0397f98: 8344316: security/auth/callback/TextCallbackHandler/Password.java make runnable with JTReg and add the UI
• aa7b3df: 8347302: Mark test tools/jimage/JImageToolTest.java as flagless

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
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.

[openjdk]

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

[mlbridge]

Webrevs

• 00: Full (f185aea7)

[JohnTortugo]

Thank you. LGTM

[TobiHartmann]

Thanks Cesar!

[TobiHartmann]

/integrate

[openjdk]

Going to push as commit d8feb0f.
Since your change was applied there have been 18 commits pushed to the master branch:

• e3d6b0a: 8348600: Update PipeWire to 1.3.81
• 2397bea: 8322983: Virtual Threads: exclude 2 tests
• cb5f489: 8346880: [aix] java/lang/ProcessHandle/InfoTest.java still fails: "reported cputime less than expected"
• 754e5dd: 8349058: 'internal proprietary API' warnings make javac warnings unusable
• 010833d: 8343978: Update the default value of CodeEntryAlignment for Ampere-1A and 1B
• ff59e5b: 8347268: [ubsan] logOutput.cpp:357:21: runtime error: applying non-zero offset 1 to null pointer
• ded2ed2: 8338303: Linux ppc64le with toolchain clang - detection failure in early JVM startup
• 2280d5b: 8347018: C2: Insertion of Assertion Predicates ignores the effects of PhaseIdealLoop::clone_up_backedge_goo()
• 63a800d: 8345590: AIX 'make all' fails after JDK-8339480
• 82ccb07: 8345569: [ubsan] adjustments to filemap.cpp and virtualspace.cpp for macOS aarch64
• ... and 8 more: https://git.openjdk.org/jdk24u/compare/9e811f1a476c819842b2375b84776963021214ed...master

Your commit was automatically rebased without conflicts.

[openjdk]

@TobiHartmann Pushed as commit d8feb0f.

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