RFR: 8302191: Performance degradation for float/double modulo on Linux [v9]

[Jan Kratochvil]

> I have OCA already processed/approved. I am not Author but my Author request is being processed these days (sent to Rob McKenna).
> I did regression test x86_64 OpenJDK-8. I will leave other regression testing on GHA.
> The patch (and former GCC performance regression) affects only x86_64+i686.

Jan Kratochvil 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 eight additional commits since the last revision:

 - Merge remote-tracking branch 'origin/master' into modulo
 - Always include the _WIN64 workaround - a review by dholmes-ora.
 - Remove comments to be moved to JBS (Bug System) - a review by jddarcy.
 - Uppercase L - a review by turbanoff.
 - Fix copyright author.
 - Fix WIN32 vs. WIN64.
 - Update according to the upstream review by David Holmes.
 - 8302191: Performance degradation for float/double modulo on Linux

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12508/files
  - new: https://git.openjdk.org/jdk/pull/12508/files/873562c8..cdcf89d7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12508&range=08
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12508&range=07-08

  Stats: 18454 lines in 676 files changed: 11810 ins; 3539 del; 3105 mod
  Patch: https://git.openjdk.org/jdk/pull/12508.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12508/head:pull/12508

PR: https://git.openjdk.org/jdk/pull/12508