RFR: 8282874: Bad performance on gather/scatter API caused by different IntSpecies of indexMap

[Jie Fu]

On Thu, 10 Mar 2022 16:32:19 GMT, Paul Sandoz <psandoz at openjdk.org> wrote:

> I think its OK, to follow up after this with some tests for "polluted" profiles of vectors (which may expose more issues). Given the scope of the fix i would recommend adding a comment in each place as to why we don't switch over the enum constant itself (note we are very careful in other performance critical areas of the JDK to avoid this e.g. in VarHandle code).

Hi @PaulSandoz ,

JDK-8282874 is labeled as a Bug.
But there is no description about how to reproduce it and verify the fix.

I think it also helps to figure out more bugs of this kind if we provide a jtreg test.
That's why I strongly recommend adding a jtreg for this fix.
Thanks.

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PR: https://git.openjdk.java.net/jdk/pull/7757