RFR: 8316594: C2 SuperWord: wrong result with hand unrolled loops [v4]

[Emanuel Peter]

> Please read description in https://github.com/openjdk/jdk/pull/15864.
> 
> Currently, we only compare the first element of the load-pack with the StoreVector. This is not correct, we need to compare all elements of the load-pack with the StoreVector. Otherwise it may be that the first element lays below/before the memory region of the StoreVector (Less), but the last element of the load-pack for example could have overlap with the StoreVector (Equal).
> 
> Tier1-6 + stress-testing.
> Performance testing.

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

  require avx2, so misalignment bug does not trigger

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/15866/files
  - new: https://git.openjdk.org/jdk/pull/15866/files/1b6b0582..7ba6adb4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15866&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15866&range=02-03

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15866.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15866/head:pull/15866

PR: https://git.openjdk.org/jdk/pull/15866