8370691: Add new HalffloatVector type and enable intrinsification of float16 vector operations

[jatin-bhateja]

Add new HalffloatVector type and corresponding concrete vector classes in addition to existing primitive vector types, maintaining operation parity with the FloatVector type.

• Add necessary inline expander support.
  • Enable intrinsification for a few vector operations, namely ADD/SUB/MUL/DIV/MAX/MIN/FMA.
• Use existing Float16 vector IR and backend support.

The idea here is to first be at par with Float16 auto-vectorization support before intrinsifying new operations (conversions, reduction, etc).

Performance of the FMA benchmark on Intel Xeon Emerald Rapids : INTEL(R) XEON(R) PLATINUM 8581C CPU @ 2.30GHz

TODO:

• Function and performance validation.

Initial RFP[1] was floated on the panama-dev mailing list.

Kindly review the draft PR and share your feedback.

Best Regards,
Jatin

[1] https://mail.openjdk.org/pipermail/panama-dev/2025-August/021100.html

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Progress

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Issue

• JDK-8370691: Add new HalffloatVector type and enable intrinsification of float16 vector operations (Enhancement - P4)

Reviewing

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$ git checkout pull/28002

Update a local copy of the PR:
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$ git pull https://git.openjdk.org/jdk.git pull/28002/head

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$ git pr checkout 28002

View PR using the GUI difftool:
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https://git.openjdk.org/jdk/pull/28002.diff

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[openjdk]

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[jatin-bhateja]

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