RFR: 8356709: Avoid redundant String formatting in BigDecimal.valueOf(double)

[Raffaello Giulietti]

On Sun, 11 May 2025 16:32:02 GMT, Johannes Graham <duke at openjdk.org> wrote:

>> Optimize `BigDecimal.valueOf(double)` by using `FormattedFPDecimal` instead of converting to decimal string and then parsing it. This results in an approximate 6x improvement for me.
>
> On Aarch64 M4:
> 
> Benchmark                                Mode  Cnt   Score   Error  Units
> + BigDecimals.testValueOfWithDouble        avgt   15   9.913 ± 0.080  ns/op
> - BigDecimals.testValueOfWithDoubleString  avgt   15  65.846 ± 0.801  ns/op

Thanks @j3graham for this nice enhancement!

Before approval, let's give another 24 hours for people around the globe to have a chance for further comments.

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PR Comment: https://git.openjdk.org/jdk/pull/25173#issuecomment-2880505868