8284937: riscv: should not allocate special register for temp

[yhzhu20]

Following testcases fail with -XX:+UseRVV after JDK-8284863：

test/hotspot/jtreg/compiler/vectorapi/VectorCastShape128Test.java
test/hotspot/jtreg/compiler/vectorapi/VectorCastShape64Test.java
test/hotspot/jtreg/compiler/vectorapi/VectorMaskCastTest.java
test/hotspot/jtreg/compiler/vectorapi/VectorMaskLoadStoreTest.java

The root cause of this problem is that special registers were allocated as temporary registers in C2. Similar issue also exists in several other C2 instructs for riscv.

With this patch, testcases above are all passed.

Additional testing:

• QEMU full with RVV enabled
• QEMU full with RVV disabled
• Native hotspot/jdk tier1 with RVV disabled

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed

Issue

• JDK-8284937: riscv: should not allocate special register for temp

Reviewers

• Fei Yang (@RealFYang - Reviewer)
• Feilong Jiang (@feilongjiang - Author)
• Yadong Wang (@yadongw - Author)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/8283/head:pull/8283
$ git checkout pull/8283

Update a local copy of the PR:
$ git checkout pull/8283
$ git pull https://git.openjdk.java.net/jdk pull/8283/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 8283

View PR using the GUI difftool:
$ git pr show -t 8283

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/8283.diff

[bridgekeeper]

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[openjdk]

@yhzhu20 The following label will be automatically applied to this pull request:

• hotspot-compiler

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[mlbridge]

Webrevs

• 00: Full (66b1d6b1)

[RealFYang]

Looks reasonable. Thanks for fixing this.

[openjdk]

@yhzhu20 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:

8284937: riscv: should not allocate special register for temp

Reviewed-by: fyang, fjiang, yadongwang

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 8 new commits pushed to the master branch:

• 87faa85: 8186958: Need method to create pre-sized HashMap
• 41fc078: 8284112: Minor cleanup could be done in javax.crypto
• 897d6c0: 8282008: Incorrect handling of quoted arguments in ProcessBuilder
• ffdeb32: 8284928: Add links from SourceVersion to specific JLS versions
• d3d71ea: 8284922: Fix some doc-comment issues on methods with package access in JDK API
• 6e36c45: 8284923: Update description of SourceVersion.RELEASE_18
• c63fabe: 8284935: Improve debug in java.security.jgss
• ef25e18: 8283870: jdeprscan --help causes an exception when the locale is ja, zh_CN or de

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.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@RealFYang) but any other Committer may sponsor as well.

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[yadongw]

Nice catch. It‘s somewhat difficult to spot.

[yhzhu20]

/integrate

[openjdk]

@yhzhu20
Your change (at version 66b1d6b) is now ready to be sponsored by a Committer.

[RealFYang]

/sponsor

[openjdk]

Going to push as commit 145dfed.
Since your change was applied there have been 8 commits pushed to the master branch:

• 87faa85: 8186958: Need method to create pre-sized HashMap
• 41fc078: 8284112: Minor cleanup could be done in javax.crypto
• 897d6c0: 8282008: Incorrect handling of quoted arguments in ProcessBuilder
• ffdeb32: 8284928: Add links from SourceVersion to specific JLS versions
• d3d71ea: 8284922: Fix some doc-comment issues on methods with package access in JDK API
• 6e36c45: 8284923: Update description of SourceVersion.RELEASE_18
• c63fabe: 8284935: Improve debug in java.security.jgss
• ef25e18: 8283870: jdeprscan --help causes an exception when the locale is ja, zh_CN or de

Your commit was automatically rebased without conflicts.

[openjdk]

@RealFYang @yhzhu20 Pushed as commit 145dfed.

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