RFR: 8323116: [REDO] Computational test more than 2x slower when AVX instructions are used [v5]

Sandhya Viswanathan sviswanathan at openjdk.org
Fri Apr 5 18:21:10 UTC 2024


On Fri, 5 Apr 2024 17:37:57 GMT, Sandhya Viswanathan <sviswanathan at openjdk.org> wrote:

>> Without this check, the test is failing for KNL (-XX:UseAVX=3 -XX:+UnlockDiagnosticVMOptions -XX:+UseKNLSetting) as Vladimir mentioned. Is there a better way to handle the KNL case?
>
> Yes, there is an easy way. For the instructs where you added the pxor instruction generation, you could change the dst register type from regF to  vlRegF. This restricts the xmm register to xmm0-xmm15 for KNL, thereby not needing the evex encoding and in-turn not needing the avx512vl support for pxor.

and likewise from regD to vlRegD.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18503#discussion_r1554083856


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