On Thu, 26 Feb 2026 04:31:09 GMT, Shawn Emery <[email protected]> wrote:

> Not a review! I've seen the `hotspot-compiler` label and I've just run some 
> testing. I've got a failure on the test 
> `compiler/codegen/aes/TestAESMain.java` using flags `-XX:UseAVX=3 
> -XX:+UnlockDiagnosticVMOptions -XX:+UseKNLSetting` on a machine with an Intel 
> Xeon Platinum 8358 Processor.

Thanks a lot for testing and reporting @marc-chevalier. 

I noticed that `-XX:+UseKNLSetting` clears several Intel AVX-512 features 
(AVX512_VAES, AVX512BW, AVX512VL, etc.) in `vm_version_x86.cpp`, which changes 
the AES intrinsic path. Unfortunately, I don’t currently have access to an 
Intel AVX-512 machine to reproduce this directly.

I tried to simulate a similar setup on an AMD EPYC 9755 (AVX-512 capable) 
machine by changing `is_intel()` to `is_amd()`, but I wasn’t able to reproduce 
the failure.

There may be some differences between Intel and AMD AVX-512 behavior, or my 
simulation might not be fully equivalent to `UseKNLSetting` on Intel.

I’ll keep investigating this and try to reproduce it on an Intel system if 
possible. Thanks again for the detailed report!

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PR Comment: https://git.openjdk.org/jdk/pull/29385#issuecomment-3964527446

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