RFR: 8284960: Integration of JEP 426: Vector API (Fourth Incubator) [v9]

[Jatin Bhateja]

> Hi All,
> 
> Patch adds the planned support for new vector operations and APIs targeted for [JEP 426: Vector API (Fourth Incubator).](https://bugs.openjdk.java.net/browse/JDK-8280173)
> 
> Following is the brief summary of changes:-
> 
> 1)  Extends the scope of existing lanewise API for following new vector operations.
>    -  VectorOperations.BIT_COUNT: counts the number of one-bits
>    - VectorOperations.LEADING_ZEROS_COUNT: counts the number of leading zero bits
>    - VectorOperations.TRAILING_ZEROS_COUNT: counts the number of trailing zero bits
>    - VectorOperations.REVERSE: reversing the order of bits
>    - VectorOperations.REVERSE_BYTES: reversing the order of bytes
>    - compress and expand bits: Semantics are based on Hacker's Delight section 7-4 Compress, or Generalized Extract.
> 
> 2)  Adds following new APIs to perform cross lane vector compress and expansion operations under the influence of a mask.
>    - Vector.compress
>    - Vector.expand 
>    - VectorMask.compress
> 
> 3) Adds predicated and non-predicated versions of following new APIs to load and store the contents of vector from foreign MemorySegments. 
>   - Vector.fromMemorySegment
>   - Vector.intoMemorySegment
> 
> 4) C2 Compiler IR enhancements and optimized X86 and AARCH64 backend support for each newly added operation.
> 
> 
>  Patch has been regressed over AARCH64 and X86 targets different AVX levels. 
> 
>  Kindly review and share your feedback.
> 
>  Best Regards,
>  Jatin

Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:

  8284960: Review comments resolved.

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8425/files
  - new: https://git.openjdk.java.net/jdk/pull/8425/files/17a0e38c..a2c9673d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8425&range=08
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8425&range=07-08

  Stats: 110 lines in 7 files changed: 42 ins; 31 del; 37 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8425.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8425/head:pull/8425

PR: https://git.openjdk.java.net/jdk/pull/8425