RFR: 8302652: [SuperWord] Reduction should happen after loop, when possible [v5]

[Andrew Haley]

On Fri, 12 May 2023 00:44:09 GMT, Sandhya Viswanathan <sviswanathan at openjdk.org> wrote:

>> @jatin-bhateja exactly. With the Vector API the vector reduction can be explicitly put outside the loop. With SuperWord, we need to take care of it in the compiler.
>
> @eme64 Very nice and clean work. Thanks a lot for taking this up.

> > @sviswa7 thanks for your quick response!
> > I can confirm: we do not "intrinsify" (ie turn into `MinL/MaxL`), rather we just inline the `java.lang.Math::Min/Max` methods, implemented with `CmpL` / `If`-branching. Do you think this makes sense, or should we intrinsify, at least when the hardware supports it?
> 
> @eme64 We should intrinsify MinL/MaxL when the hardware supports it.

I doubt it, unless there really is a performance payoff.

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PR Comment: https://git.openjdk.org/jdk/pull/13056#issuecomment-1556906978