RFR: 8350463: AArch64: Add vector rearrange support for small lane count vectors

[Xiaohong Gong]

On Mon, 17 Mar 2025 07:33:16 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> But the testing on my side so far looks good. I'll rerun once you add your IR tests.
>
>> Thanks for looking at this PR again @eme64 ! Vector API has its own jtreg tests under `test/jdk/jdk/incubator/vector/`. I double checked that it has the `rearrange` test for all vector species. Please see one of the test here: https://github.com/openjdk/jdk/blob/master/test/jdk/jdk/incubator/vector/Long128VectorTests.java#L4954 That's also way I did not add the correct tests in the IR test file.
> 
> Alright. I think result verification would still be good practice, and not too difficult to do using a `@Check` method and `Verify.java` for comparing the resulting arrays. But I leave that up to you. In my experience, the VectorAPI test coverage is not as good as I first thought, see the list of bugs I recently found:
> https://bugs.openjdk.org/issues/?jql=labels%20%3D%20template-framework%20ORDER%20BY%20created%20DESC%2C%20summary%20DESC
> 
> So adding a little more rigor to your IR test could catch possible bugs that the existing tests simply do not cover.

Hi @eme64 , the IR test is updated according to your suggestion. Could you please look at it again? Thanks so much!

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PR Comment: https://git.openjdk.org/jdk/pull/23790#issuecomment-2731435519