RFR: 8324751: C2 SuperWord: Aliasing Analysis runtime check [v11]

[Vladimir Kozlov]

On Mon, 18 Aug 2025 06:20:57 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> src/hotspot/share/opto/c2_globals.hpp line 367:
>> 
>>> 365:                                                                             \
>>> 366:   product(bool, UseAutoVectorizationPredicate, true, DIAGNOSTIC,            \
>>> 367:           "Use AutoVectorization predicate (for speculative compilation)")  \
>> 
>> I do not see benchmarks results with this flag off.
>
> Would that be helpful to you? How?
> What would you expect to see here @vnkozlov ?
> This is really an optimization that reduces the code-size.
> Or do you just want to sanity-check that the peek performance would be identical if we use multiversioning rather than the predicate approach?

You did benchmarking for `LoopMultiversioningOptimizeSlowLoop`.

> use multiversioning rather than the predicate approach

This one.

Does alias analysis runtime checks requires both, multiversion and predicate, or can work only with one?
If both enabled, which one you select for alias analisys?

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PR Review Comment: https://git.openjdk.org/jdk/pull/24278#discussion_r2282630952