8318158: RISC-V: implement roundD/roundF intrinsics

[omikhaltsova]

I would like to backport JDK-8318158 to jdk21u in order to optimize performance in double/float rounding operations by means of intrinsics.
The patch applied cleanly.
Tested: tier1 tests passed.

The benchmark shows the following performance improvement on the T-Head RVB-ICE board:
Before

Benchmark                              (TESTSIZE)   Mode  Cnt   Score   Error   Units
FpRoundingBenchmark.test_round_double        2048  thrpt   15  58.679 ± 0.965  ops/ms
FpRoundingBenchmark.test_round_float         2048  thrpt   15  49.252 ± 0.887  ops/ms

After

Benchmark                              (TESTSIZE)   Mode  Cnt    Score   Error   Units
FpRoundingBenchmark.test_round_double        2048  thrpt   15  117.264 ± 1.254  ops/ms
FpRoundingBenchmark.test_round_float         2048  thrpt   15  119.752 ± 1.751  ops/ms

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8318158 needs maintainer approval

Issue

• JDK-8318158: RISC-V: implement roundD/roundF intrinsics (Enhancement - P4 - Approved)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk21u-dev.git pull/161/head:pull/161
$ git checkout pull/161

Update a local copy of the PR:
$ git checkout pull/161
$ git pull https://git.openjdk.org/jdk21u-dev.git pull/161/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 161

View PR using the GUI difftool:
$ git pr show -t 161

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk21u-dev/pull/161.diff

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[bridgekeeper]

👋 Welcome back omikhaltcova! 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]

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

[openjdk]

⚠️ @omikhaltsova 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 (bf34f146)

[omikhaltsova]

/approval request Clean backport, related only to RISC-V platform, to optimize performance in double/float rounding operations via intrinsics.

[openjdk]

@omikhaltsova
8318158: The approval request has been created successfully.

[openjdk]

@omikhaltsova 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:

8318158: RISC-V: implement roundD/roundF intrinsics

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 81 new commits pushed to the master branch:

• 69416f4: 8318809: java/util/concurrent/ConcurrentLinkedQueue/WhiteBox.java shows intermittent failures on linux ppc64le and aarch64
• c01bdbb: 8314283: Support for NSS tests on aarch64 platforms
• c3657ee: 8317771: [macos14] Expand/collapse a JTree using keyboard freezes the application in macOS 14 Sonoma
• 95e36bc: 8322279: Generational ZGC: Use ZFragmentationLimit and ZYoungCompactionLimit as percentage instead of multiples
• 6443937: 8323008: filter out harmful -std* flags added by autoconf from CXX
• c8f0418: 8310031: Parallel: Implement better work distribution for large object arrays in old gen
• 0d30c8d: 8318590: JButton ignores margin when painting HTML text
• 8413dc0: 8312136: Modify runtime/ErrorHandling/TestDwarf.java to split dwarf and decoder testing
• c79c5ef: 8315241: (fs) Move toRealPath tests in java/nio/file/Path/Misc.java to separate JUnit 5 test
• 7eea17b: 8311663: Additional refactoring of Locale tests to JUnit
• ... and 71 more: https://git.openjdk.org/jdk21u-dev/compare/cd166703a20c4ac51bc6478e8a0bb1275d9cb913...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.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[omikhaltsova]

/integrate

[openjdk]

Going to push as commit ada400c.
Since your change was applied there have been 83 commits pushed to the master branch:

• 1dd2f2a: 8169475: WheelModifier.java fails by timeout
• e9be531: 8077371: Binary files in JAXP test should be removed
• 69416f4: 8318809: java/util/concurrent/ConcurrentLinkedQueue/WhiteBox.java shows intermittent failures on linux ppc64le and aarch64
• c01bdbb: 8314283: Support for NSS tests on aarch64 platforms
• c3657ee: 8317771: [macos14] Expand/collapse a JTree using keyboard freezes the application in macOS 14 Sonoma
• 95e36bc: 8322279: Generational ZGC: Use ZFragmentationLimit and ZYoungCompactionLimit as percentage instead of multiples
• 6443937: 8323008: filter out harmful -std* flags added by autoconf from CXX
• c8f0418: 8310031: Parallel: Implement better work distribution for large object arrays in old gen
• 0d30c8d: 8318590: JButton ignores margin when painting HTML text
• 8413dc0: 8312136: Modify runtime/ErrorHandling/TestDwarf.java to split dwarf and decoder testing
• ... and 73 more: https://git.openjdk.org/jdk21u-dev/compare/cd166703a20c4ac51bc6478e8a0bb1275d9cb913...master

Your commit was automatically rebased without conflicts.

[openjdk]

@omikhaltsova Pushed as commit ada400c.

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