RFR: 8325083: jdk/incubator/vector/Double512VectorTests.java crashes in Assembler::vex_prefix_and_encode [v3]

[Jatin Bhateja]

> This bugfix patch limits the register class for operands of byte to double cast pattern to prevent reported assertion failure on Knights family CPUs.
> 
> 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:

  Review suggestion incorporated.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19407/files
  - new: https://git.openjdk.org/jdk/pull/19407/files/78699f0c..098157e8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19407&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19407&range=01-02

  Stats: 138 lines in 4 files changed: 126 ins; 9 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/19407.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19407/head:pull/19407

PR: https://git.openjdk.org/jdk/pull/19407