FP16 isNaN, isFinite, isInfinite intrinsics without Reinterpret nodes

[Bhavana-Kilambi]

This patch removes the ReinterpretS2HF nodes in the mid-end during the generation of isNaNHF,isFiniteHF and isInfiniteHF nodes.

Performance results for this patch on an aarch64 machine -

Benchmark               Gain over baseline      Gain over default
FP16Ops.isFiniteHF      1.29                    1.85
FP16Ops.isInfiniteHF    1.28                    1.90
FP16Ops.isNaNHF         1.45                    1.58

The baseline patch generates floating point FP16 instructions and the default is where no FP16 intrinsics are used and FP32 instructions are generated.

Gain : thrpt of this patch / thrpt of either baseline or default

Tested FP16Ops.isInfiniteHF test on x86 and the performance is 2.6x better over the default case (which converts FP16 to FP32 and uses the vfpclass instruction).

The JMH tests are added in this patch.

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Progress

• [x] Change must not contain extraneous whitespace

Reviewers

• @Babbz86 (no known openjdk.org user name / role)

Reviewing

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[bridgekeeper[bot]]

:wave: Welcome back bkilambi! A progress list of the required criteria for merging this PR into lworld+fp16 will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk[bot]]

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[Bhavana-Kilambi]

Closing as the other PR opened for implementing isNaN, isfinite and isInfinite for FP16 has been approved and integrated.