RFR: 8333840: C2 SuperWord: wrong result for MulAddS2I when inputs permuted [v2]

[Emanuel Peter]

> This is an older bug, I discovered it by manual code inspection while refactoring.
> 
> I added some regression tests that produced wrong results.
> 
> You should understand the fix given the comments in the code, if not: tell me how to improve them ;)

Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:

  improve naming

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19619/files
  - new: https://git.openjdk.org/jdk/pull/19619/files/c4c3305f..a14839c0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19619&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19619&range=00-01

  Stats: 7 lines in 2 files changed: 0 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/19619.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19619/head:pull/19619

PR: https://git.openjdk.org/jdk/pull/19619