RFR: JDK-8301392: Port fdlibm log1p to Java [v5]

[Brian Burkhalter]

On Thu, 2 Feb 2023 18:06:00 GMT, Joe Darcy <darcy at openjdk.org> wrote:

>> Another day, another PR to port FDLBIM to Java, this time for the log1p method.
>> 
>> Other than using the two-argument form of the __HI method in Java transliteration version rather than C macro, there are no appreciable differences between the original C source in 
>> 
>> src/java.base/share/native/libfdlibm/s_log1p.c
>> 
>> and the transliteration for testing purposes in
>> 
>> test/jdk/java/lang/StrictMath/FdlibmTranslit.java
>> 
>> The more idiomatic port in
>> 
>> src/java.base/share/classes/java/lang/FdLibm.java
>> 
>> has had a series of transformation applied layering on the transliteration. The intermediate commits show the progress.
>> 
>> The regression tests include probing around input values the implementation uses to decided which branch to take.
>
> Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Refine test per code review feedback.

No problems apparent to me: Reviewed.

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Marked as reviewed by bpb (Reviewer).

PR: https://git.openjdk.org/jdk/pull/12301