[jdk17u-dev] RFR: 8269404: Base64 Encoding optimization enhancements for x86 using AVX-512 [v3]

[Scott Gibbons]

> This is a backport of JDK-8269404: Base64 Encoding optimization enhancements for x86 using AVX-512. Backport is clean.
> 
> We have had numerous customer requests for this functionality to be backported due to the performance improvement.
> 
> There will be three additional PRs for which this is a dependency. This PR is dependent on PR #860.
> 
> Risk: I view the risk of this backport to be minimal. This code has been in use for many months with no bugs reported.
> 
> Testing: x86_64 build, affected tests, tier1
> 
> Thanks,
> --Scott

Scott Gibbons 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 three additional commits since the last revision:

 - Merge branch 'master' into Encode-backport
 - Backport 9cac94d581f240c10fe8fff2f803109a1ae30637
 - Backport c37988d0793b24d98d285530dfda69999a227937

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

Changes:
  - all: https://git.openjdk.org/jdk17u-dev/pull/861/files
  - new: https://git.openjdk.org/jdk17u-dev/pull/861/files/e8ff3f11..e661488a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=861&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=861&range=01-02

  Stats: 1119 lines in 20 files changed: 887 ins; 2 del; 230 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/861.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/861/head:pull/861

PR: https://git.openjdk.org/jdk17u-dev/pull/861