RFR: 8350835: C2 SuperWord: assert/wrong result when using Float.float16ToFloat with byte instead of short input [v2]

[Sandhya Viswanathan]

On Wed, 12 Mar 2025 14:15:56 GMT, Sandhya Viswanathan <sviswanathan at openjdk.org> wrote:

>> test/hotspot/jtreg/compiler/vectorization/TestFloat16ToFloatConv.java line 78:
>> 
>>> 76:     @IR(counts = {IRNode.VECTOR_CAST_HF2F, "> 0"},
>>> 77:         applyIfOr = {"UseCompactObjectHeaders", "false", "AlignVector", "false"},
>>> 78:         applyIfPlatformOr = {"x64", "true", "aarch64", "true", "riscv64", "true"},
>> 
>> Can you kindly justify the need for compressed object header usage,  it will mainly impact the pre-loop trip count compuation. AlignVector should be sufficient since it's a whitelisted option
>
> This check is taken from compiler/vectorization/TestFloatConversionsVector.java which also has float16 conversion tests to be in sync.

If I remove UseCompressedHeaders check then the test will start failing for folks working on compressed headers so good to keep it there and as I mentioned before it is good to be in sync with other Float16ToFloat conversion test.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23939#discussion_r1996470864