RFR: 8304301: Remove the global option SuperWordMaxVectorSize

[Vladimir Kozlov]

On Tue, 21 Mar 2023 02:26:55 GMT, Fei Gao <fgao at openjdk.org> wrote:

> After the patch, auto-vectorization is still limited to 32-byte vectors by default on Cascade Lake and users can override this by either setting `-XX:UseAVX=3` or `-XX:MaxVectorSize=64` on JVM command line.

Correction: only `-XX:MaxVectorSize=64` will affect it. `-XX:UseAVX=3` does not affect superword vector size on CL because the condition for CL already includes `UseAVX > 2`.  And with `-XX:UseAVX=2` all vectors are limited to 32 bytes on all platforms.

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PR Comment: https://git.openjdk.org/jdk/pull/13112#issuecomment-1480289084