RFR: 8371820: Further AES performance improvements for key schedule generation

Thu Nov 13 16:56:36 UTC 2025

This fix simplifies the hotspot intrinsics for some platforms and optimizes the key computation for encryption. We can save the `genInvRoundKeys` computation when we only do encryption.

The micro:org.openjdk.bench.javax.crypto.AESReinit benchmark results are improved by 17% for ppc64 and 26% for x86_64.

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Commit messages:
 - 8371820: Further AES performance improvements for key schedule generation

Changes: https://git.openjdk.org/jdk/pull/28299/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28299&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8371820
  Stats: 33 lines in 2 files changed: 12 ins; 8 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/28299.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28299/head:pull/28299

PR: https://git.openjdk.org/jdk/pull/28299