RFR: 8369881: C2: Unexpected node in SuperWord truncation: ReverseBytesS, ReverseBytesUS

[Christian Hagedorn]

On Wed, 15 Oct 2025 09:14:22 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

>> The fuzzer found the `ReverseByteS` case, and I checked all other `*.reverseBytes`, and found a failure with `Character.reverseBytes` as well.
>> 
>> Adding them to the list, and added tests for both.
>> 
>> Note, this is just another 2 boxes checked, there were many similar ones fixed, or on the way:
>> https://github.com/openjdk/jdk/pull/26827
>> https://github.com/openjdk/jdk/pull/26334
>> https://github.com/openjdk/jdk/pull/26494
>> https://github.com/openjdk/jdk/pull/26423
>
> test/hotspot/jtreg/compiler/vectorization/TestSubwordTruncation.java line 355:
> 
>> 353: 
>> 354:     @Test
>> 355:     @IR(counts = { IRNode.STORE_VECTOR, "=0" })
> 
> You could use `failOn` instead. Same below.

Okay, I see that we use `= 0` in the other tests as well further down. Feel free to ignore.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27819#discussion_r2431783384