RFR: 8268151: Vector API toShuffle optimization [v2]

[Sandhya Viswanathan]

> The Vector API toShuffle method can be optimized  using existing vector conversion intrinsic.
> 
> The following changes are made:
> 1) vector.toShuffle java implementation is changed to call VectorSupport.convert.
> 2) The conversion intrinsic (inline_vector_convert()) in vectorIntrinsics.cpp is changed to allow shuffle as a destination type.
> 3) The shuffle.toVector intrinsic (inline_vector_shuffle_to_vector()) in vectorIntrinsics.cpp now explicitly generates conversion node instead of performing conversion during unbox. This is to remove unnecessary boxing during back to back vector.toShuffle and shuffle.toVector calls. 
> 
> Best Regards,
> Sandhya

Sandhya Viswanathan has updated the pull request incrementally with one additional commit since the last revision:

  Implement review comments

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4326/files
  - new: https://git.openjdk.java.net/jdk/pull/4326/files/d5652051..ab582a1c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4326&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4326&range=00-01

  Stats: 657 lines in 38 files changed: 161 ins; 465 del; 31 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4326.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4326/head:pull/4326

PR: https://git.openjdk.java.net/jdk/pull/4326