8356924: RISC-V: Clean up cost for vector instructions

[DingliZhang]

As mentioned in https://bugs.openjdk.org/browse/JDK-8285790 regarding the ARM64 vector instruct modifications:
Since the new rules are unique and setting different "ins_cost" makes no sense, we have switched to using the default cost.

Currently, there is a similar situation on RISC-V. Over half of the instructions in riscv_v.ad do not include ins_cost definitions. Additionally, as RVV nodes are also unique, we can unify the format by removing these ins_cost entries from riscv_v.ad.

Testing

qemu-system 9.2.3 with UseRVV (ubuntu24.10):

• Run test/jdk/jdk/incubator/vector (fastdebug)
• Run test/hotspot/jtreg/compiler/vectorapi (fastdebug)

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
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• Commit message must refer to an issue

Issue

• JDK-8356924: RISC-V: Clean up cost for vector instructions (Enhancement - P4)

Reviewers

• Gui Cao (@zifeihan - Author) Review applies to 80ab16a5
• Feilong Jiang (@feilongjiang - Committer)
• Fei Yang (@RealFYang - Reviewer)

Reviewing

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[bridgekeeper]

👋 Welcome back dzhang! 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]

@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:

8356924: RISC-V: Clean up cost for vector instructions

Reviewed-by: fjiang, fyang, gcao

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At the time when this comment was updated there had been 23 new commits pushed to the master branch:

• a4f66f5: 8325859: Potential information loss during type inference
• 2c126f1: 8357370: Export supported GCs in JVMCI
• b8057cf: 8357436: Change jspawnhelper warning recommendation from VFORK to FORK
• ... and 20 more: https://git.openjdk.org/jdk/compare/e961b13cd68bc352b86af17c7e53df8537519beb...master

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[openjdk]

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

• hotspot-compiler

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[mlbridge]

Webrevs

• 01: Full - Incremental (44521d8a)
• 00: Full (80ab16a5)

[zifeihan]

LGTM.

[feilongjiang]

Looks fine.

[RealFYang]

Thanks!

[DingliZhang]

Thanks all for the review.
/integrate

[openjdk]

@DingliZhang
Your change (at version 44521d8) is now ready to be sponsored by a Committer.

[feilongjiang]

/sponsor

[openjdk]

Going to push as commit 108e454.
Since your change was applied there have been 23 commits pushed to the master branch:

• a4f66f5: 8325859: Potential information loss during type inference
• 2c126f1: 8357370: Export supported GCs in JVMCI
• b8057cf: 8357436: Change jspawnhelper warning recommendation from VFORK to FORK
• ... and 20 more: https://git.openjdk.org/jdk/compare/e961b13cd68bc352b86af17c7e53df8537519beb...master

Your commit was automatically rebased without conflicts.

[openjdk]

@feilongjiang @DingliZhang Pushed as commit 108e454.

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