RFR: 8342095: Add autovectorizer support for subword vector casts [v15]

[Emanuel Peter]

On Fri, 23 Jan 2026 08:57:15 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Jasmine Karthikeyan has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 19 commits:
>> 
>>  - Fix whitespace
>>  - Update tests after merge, apply changes from review
>>  - Merge from master
>>  - Update tests, cleanup logic
>>  - Merge branch 'master' into vectorize-subword
>>  - Check for AVX2 for byte/long conversions
>>  - Whitespace and benchmark tweak
>>  - Address more comments, make test and benchmark more exhaustive
>>  - Merge from master
>>  - Fix copyright after merge
>>  - ... and 9 more: https://git.openjdk.org/jdk/compare/de6f35ef...13378368
>
> test/hotspot/jtreg/compiler/vectorization/TestRotateByteAndShortVector.java line 122:
> 
>> 120:     @IR(counts = { IRNode.LOAD_VECTOR_B, IRNode.VECTOR_SIZE + "min(max_int, max_byte)", "> 0",
>> 121:                    IRNode.ROTATE_LEFT_V, "> 0" },
>> 122:         applyIfCPUFeature = {"avx512f", "true"})
> 
> We could also improve things here, right? Or is there a reason why we need to cast from and to int?
> 
> Do you agree that we should file an RFE to track this?

Can you add the current issue/bug/RFE number to all the files JTREG `@bug` annotations, please :)

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PR Review Comment: https://git.openjdk.org/jdk/pull/23413#discussion_r2720310350