8353600: RISC-V: compiler/vectorization/TestRotateByteAndShortVector.java is failing with Zvbb

[Hamlin-Li]

Hi,
Can you help to review this patch?

Currently, the followign code is considered an RotateLeftV of byte by hotspot, but it's not a real rotate, as the -shift will 30, which makes b >> -shift zero, rather the value we expected.

int shift = 2;
byte b = 83;
byte res = (byte) (b << shift | b >> -shift); // res = 76
// but a real left rotate of 83 should be 77 ??

So, the simple fix is to enable RotateLeftV only for int and long, disable it for other types.

A more rational fix should be change C2 to not convert code like (byte) (b << shift | b >> -shift) to a RotateLeftV node, but it needs more investigation, and I'm not sure if it's feasible to do so, as currently no platform support RotateLeftV for non-int/long types.

The vector instruction behaviour is different from java language spec, so seems there is no way to do it for now.

Thanks!

---

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Issue

• JDK-8353600: RISC-V: compiler/vectorization/TestRotateByteAndShortVector.java is failing with Zvbb (Bug - P4)

Reviewers

• Fei Yang (@RealFYang - Reviewer)
• Ludovic Henry (@luhenry - Committer)

Reviewing

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[bridgekeeper]

👋 Welcome back mli! 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]

@Hamlin-Li 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:

8353600: RISC-V: compiler/vectorization/TestRotateByteAndShortVector.java is failing with Zvbb

Reviewed-by: fyang, luhenry

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 74 new commits pushed to the master branch:

• b3751b9: 8353573: System giflib not found by configure if it's not in system directories
• 3d24f1a: 8353580: libjpeg is not found if not installed in system directories
• d8bed13: 8353945: Test javax/security/auth/x500/X500Principal/NameFormat.java fails after JDK-8349890
• ... and 71 more: https://git.openjdk.org/jdk/compare/296d9d6f7a734cc2bab21c58f21a941150b4cf2a...master

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.

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[openjdk]

@Hamlin-Li this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout disable-rotatev-byte-short
git fetch https://git.openjdk.org/jdk.git master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

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[mlbridge]

Webrevs

• 02: Full - Incremental (592d4270)
• 01: Full - Incremental (fa5e7375)
• 00: Full (ca44d6b8)

[RealFYang]

LGTM. Thanks for fixing this!

[Hamlin-Li]

Thanks for your reviews @RealFYang @luhenry !

[Hamlin-Li]

/integrate

[openjdk]

Going to push as commit cc5e938.
Since your change was applied there have been 75 commits pushed to the master branch:

• 21db0fd: 8353665: RISC-V: IR verification fails in TestSubNodeFloatDoubleNegation.java
• b3751b9: 8353573: System giflib not found by configure if it's not in system directories
• 3d24f1a: 8353580: libjpeg is not found if not installed in system directories
• ... and 72 more: https://git.openjdk.org/jdk/compare/296d9d6f7a734cc2bab21c58f21a941150b4cf2a...master

Your commit was automatically rebased without conflicts.

[openjdk]

@Hamlin-Li Pushed as commit cc5e938.

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