RFR: JDK-8316708: Augment WorstCaseTests with more cases [v3]

[Joe Darcy]

On Sat, 24 Feb 2024 20:31:13 GMT, Joe Darcy <darcy at openjdk.org> wrote:

>> A new paper
>> 
>>  "Accuracy of Mathematical Functions in Single, Double, Double Extended, and Quadruple Precision"
>> by Brian Gladman, Vincenzo Innocente and Paul Zimmermann
>> https://members.loria.fr/PZimmermann/papers/accuracy.pdf
>> 
>> details the inputs with generate the worst-case observed errors in different math library implementations. The FDLIBM-related worst cases should be added to the test suite.
>
> Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Improve comments, implement review feedback.

To improve the "fingerprinting" coverage of the StrictMath tests, I've added test cases where the worst-case of a non-FDLIBM library is larger than the FDLIBM worst-case. Assuming reasonable methodology of the paper, the output of the other math library must differ from FDLIBM at such a point.

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PR Comment: https://git.openjdk.org/jdk/pull/15879#issuecomment-1963421766