8367066: RISC-V: refine register selection in MacroAssembler:: decode_klass_not_null

[DingliZhang]

Hi all,

This pull request contains a backport of commit 0b3a3030 from the openjdk/jdk repository.

The commit being backported was authored by Hamlin Li on 11 Sep 2025 and was reviewed by Fei Yang and Feilong Jiang.

Thanks!

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8367066 needs maintainer approval

Issue

• JDK-8367066: RISC-V: refine register selection in MacroAssembler:: decode_klass_not_null (Bug - P4 - Approved)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk25u.git pull/185/head:pull/185
$ git checkout pull/185

Update a local copy of the PR:
$ git checkout pull/185
$ git pull https://git.openjdk.org/jdk25u.git pull/185/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 185

View PR using the GUI difftool:
$ git pr show -t 185

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk25u/pull/185.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

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[openjdk]

@DingliZhang 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:

8367066: RISC-V: refine register selection in MacroAssembler:: decode_klass_not_null

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[openjdk]

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

[openjdk]

⚠️ @DingliZhang This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[mlbridge]

Webrevs

• 00: Full (01b22e5a)

[DingliZhang]

/approval request Same issue exists in jdk25u repo as well.
Backport a refinement to the register selection in MacroAssembler::decode_klass_not_null to improve readability.
This is a RISC-V specific change, should be low risk.

[openjdk]

@DingliZhang
8367066: The approval request has been created successfully.

[DingliZhang]

PS: tier1 tested on sg2042.
/integrate

[openjdk]

@DingliZhang
Your change (at version 01b22e5) is now ready to be sponsored by a Committer.

[RealFYang]

/sponsor

[openjdk]

Going to push as commit 4ad231a.

[openjdk]

@RealFYang @DingliZhang Pushed as commit 4ad231a.

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