RFR: 8265128: [REDO] Optimize Vector API slice and unslice operations [v4]

[Paul Sandoz]

On Mon, 10 May 2021 18:31:30 GMT, Sandhya Viswanathan <sviswanathan at openjdk.org> wrote:

>> All the slice and unslice variants that take more than one argument can benefit from already intrinsic methods on similar lines as slice(origin) and unslice(origin).
>> 
>> Changes include:
>>  * Rewrite Vector API slice/unslice using already intrinsic methods
>>  * Fix in library_call.cpp:inline_preconditions_checkIndex() to not modify control if intrinsification fails
>>  * Vector API conversion tests thresholds adjustment
>>  
>> Base Performance:
>> Benchmark (size) Mode Cnt Score Error Units
>> TestSlice.vectorSliceOrigin 1024 thrpt 5 11763.372 ± 254.580 ops/ms
>> TestSlice.vectorSliceOriginVector 1024 thrpt 5 599.286 ± 326.770 ops/ms
>> TestSlice.vectorSliceUnsliceOrigin 1024 thrpt 5 6627.601 ± 22.060 ops/ms
>> TestSlice.vectorSliceUnsliceOriginVector 1024 thrpt 5 401.858 ± 220.340 ops/ms
>> TestSlice.vectorSliceUnsliceOriginVectorPart 1024 thrpt 5 421.993 ± 231.703 ops/ms
>> 
>> Performance with patch:
>> Benchmark (size) Mode Cnt Score Error Units
>> TestSlice.vectorSliceOrigin 1024 thrpt 5 11792.091 ± 37.296 ops/ms
>> TestSlice.vectorSliceOriginVector 1024 thrpt 5 8388.174 ± 115.886 ops/ms
>> TestSlice.vectorSliceUnsliceOrigin 1024 thrpt 5 6662.159 ± 8.203 ops/ms
>> TestSlice.vectorSliceUnsliceOriginVector 1024 thrpt 5 5206.300 ± 43.637 ops/ms
>> TestSlice.vectorSliceUnsliceOriginVectorPart 1024 thrpt 5 5194.278 ± 13.376 ops/ms
>
> Sandhya Viswanathan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   library_call.cpp changes not needed after Objects.checkIndex arguments fixed

I don't claim to understand the HotSpot details, but Java changes still look good.

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Marked as reviewed by psandoz (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/3804