RFR: 8338694: x86_64 intrinsic for tanh using libm [v2]

[Jatin Bhateja]

On Tue, 27 Aug 2024 22:23:44 GMT, Srinivas Vamsi Parasa <duke at openjdk.org> wrote:

>> I agree, this is all rather obscure. Ideally the same names that are used in wherever this comes from.
>> 
>> Where does the algorithm come from? What are its accuracy guarantees?
>> 
>> In addition, given the rarity of hyperbolic tangents in Java applications, do we need this?
>
> @theRealAph, this implementation is based on Intel libm math library and meets the accuracy requirements. The algorithm is provided in the comments.

@vamsi-parasa  don't hesitate in adding as much and explicit information about the original source from where the algorithm has been picked up, even though the PR explicitly mentions libm. Adding the link to source references is a good practice.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20657#discussion_r1742887385