RFR: 8321712: C2: "failed: Multiple uses of register" in C2_MacroAssembler::vminmax_fp [v2]

[Sandhya Viswanathan]

On Tue, 9 Jan 2024 19:55:03 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Sandhya Viswanathan has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   review comments
>
> Actually Ideal transformation fix could be smaller than these changes. You will not need to change platform specific code. Hmm, may be NaN values could be a problem. Have to check for them as we do in other operations. Even suggested "short cut" (use move) could be wrong for NaN.
> 
> Okay, lets go to the first version of these changes: only assert fix. And file separate RFE to make changes in Ideal graph.
> 
> And we need regression test as @eme64 pointed.

@vnkozlov I have reverted the changes to just asserts and added a test case to the existing test. The new test case fails without this PR and passes with the PR changes.
@eme64 I have verified that [Test_276.java](https://bugs.openjdk.org/secure/attachment/107681/Test_276.java) fails without this PR with the given arguments in the [JBS Bug Entry](https://bugs.openjdk.org/browse/JDK-8322090) and passes with the PR changes. 
I have filed an [RFE](https://bugs.openjdk.org/browse/JDK-8323429) for future optimization as requested.

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PR Comment: https://git.openjdk.org/jdk/pull/17315#issuecomment-1883949886