RFR: 8371820: Further AES performance improvements for key schedule generation [v3]

[Valerie Peng]

On Fri, 14 Nov 2025 17:21:50 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

>> 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.
>
> Martin Doerr has updated the pull request incrementally with one additional commit since the last revision:
> 
>   More minor cleanup.

src/java.base/share/classes/com/sun/crypto/provider/AES_Crypt.java line 62:

> 60:     private int[] sessionKe = null; // key for encryption
> 61:     private int[] sessionKd = null; // preprocessed key for decryption
> 62:     private int[] K = null; // preprocessed key in case of decryption

I find the comment confusing as `K` is sometimes assigned with `sessionKe`, so it can't be used only for decryption?

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PR Review Comment: https://git.openjdk.org/jdk/pull/28299#discussion_r2539296610