8318509: x86 count_positives intrinsic broken for -XX:AVX3Threshold=0

[satyenme]

Backporting JDK-8318509: x86 count_positives intrinsic broken for -XX:AVX3Threshold=0. Fix pulls the value from tmp1, which contains the correct value. Adds test. Ran GHA Sanity Checks, local Tier 1 and 2, and new test/hotspot/jtreg/compiler/intrinsics/string/TestCountPositives.java tests. Patch is clean.

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Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8318509 needs maintainer approval

Issue

• JDK-8318509: x86 count_positives intrinsic broken for -XX:AVX3Threshold=0 (Bug - P4 - Requested)

Reviewing

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$ git checkout pull/1726

Update a local copy of the PR:
$ git checkout pull/1726
$ git pull https://git.openjdk.org/jdk21u-dev.git pull/1726/head

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$ git pr checkout 1726

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https://git.openjdk.org/jdk21u-dev/pull/1726.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back ssubramaniam! 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 change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

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

[openjdk]

⚠️ @satyenme 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 (5fead04c)

[satyenme]

/approval request for backport. Fix pulls the value from tmp1 variable, which contains the correct value in the problematic edge case.

Risk: Low. Tip change was merged in October 2023 and adjusts existing tests to confirm functionality is correct.

Testing:

• GHA Sanity Checks
• Tier 1 and 2 tests locally
• Two tests adjusted by the backport

[openjdk]

@satyenme
8318509: The approval request has been created successfully.