[vectorIntrinsics] RFR: 8283598: [vectorapi] Add new vector operation for compress bits

[Quan Anh Mai]

On Thu, 24 Mar 2022 06:31:31 GMT, Smita Kamath <svkamath at openjdk.org> wrote:

> Hi,
> 
> I've added support for new vector operations for compressing bits of integral vector types(Byte/Short/Integer/Long).
> The implementation is based on Compress or Generalized Extract mentioned in Hackers Delight by Henry S. Warren, Jr.
> The implementation does the following: given a mask and the number to be compressed, the bits of the number corresponding to the set mask bit are selected and compressed. 
> 
> Currently, this PR addresses only Java changes for compress bits operation. I've also updated the test framework.
> Do review and share feedback.

Hi, what do you think about adding this operation for scalar first, and then adding it to vector api later. We could add several other bit manipulation operations such as `bitCount` and `numberOfLeadingZeros` for `Byte` and `Short` also.
Thanks.

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PR: https://git.openjdk.java.net/panama-vector/pull/184