RFR: 8289552: Make intrinsic conversions between bit representations of half precision values and floats [v12]

[Smita Kamath]

> 8289552: Make intrinsic conversions between bit representations of half precision values and floats

Smita Kamath has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 13 additional commits since the last revision:

 - Updated instruction definition
 - Merge branch 'master'
 - Addressed review comment to update test case
 - Addressed review comments
 - Merge branch 'master' of https://git.openjdk.java.net/jdk into JDK-8289552
 - Addressed review comments
 - Added missing parantheses
 - Addressed review comments, updated microbenchmark
 - Updated copyright comment
 - Updated test cases as per review comments
 - ... and 3 more: https://git.openjdk.org/jdk/compare/ac2b491b...69999ce4

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Changes:
  - all: https://git.openjdk.org/jdk/pull/9781/files
  - new: https://git.openjdk.org/jdk/pull/9781/files/8ccc0657..69999ce4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9781&range=11
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9781&range=10-11

  Stats: 14672 lines in 427 files changed: 7255 ins; 5491 del; 1926 mod
  Patch: https://git.openjdk.org/jdk/pull/9781.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9781/head:pull/9781

PR: https://git.openjdk.org/jdk/pull/9781