RFR: 8371820: Further AES performance improvements for key schedule generation [v4]

[Martin Doerr]

On Sun, 23 Nov 2025 05:27:23 GMT, Shawn M Emery <duke at openjdk.org> wrote:

> It looks like the S390 architecture uses it for encryption and decryption in AES/CTR mode, but S390 only needs the symmetric key to derive the encryption and decryption schedules. This can be found for both in the first round. For x86, yes, encryption is only performed for both AES/CTR and AES/GCM. So, yes, I think having the 'is_decrypt' argument explicit would be ideal. nit: some comments still refer to the 'K' array in src/hotspot/cpu/x86/stubGenerator_x86_64_aes.cpp, src/hotspot/share/opto/library_call.cpp, src/hotspot/cpu/riscv/stubGenerator_riscv.cpp (line 2446), and src/hotspot/cpu/ppc/stubGenerator_ppc.cpp.

Thanks for your feedback! I've made the changes with https://github.com/openjdk/jdk/pull/28299/commits/30b5b531338c225e505a30dcca3453e35b68b256. I hope I found all places.

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PR Comment: https://git.openjdk.org/jdk/pull/28299#issuecomment-3571788446