RFR: 8285868: x86_64 intrinsics for floating point methods isNaN, isFinite and isInfinite [v8]

[Vladimir Kozlov]

On Sat, 21 May 2022 07:40:20 GMT, Srinivas Vamsi Parasa <duke at openjdk.java.net> wrote:

> For 32bit, in the case of double, we see performance improvement using `vfpclasssd` instruction but **without** `vfpclassd`, we see **40% decrease** in performance for `isFinite()` compared to the original Java code. Below, is the code which implements the intrinsic using SSE.
> 
> Is it Ok to skip support for **non** `vfpclassd` for 32bit?

Yes, but add comment about that. Also for 32-bit you need to check SSE2 support which is required by `pshuflw`.

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PR: https://git.openjdk.java.net/jdk/pull/8459