RFR: 8374540: Add comment describing implementaiton choices of Math.fma [v2]

[Eirik Bjørsnøs]

On Mon, 5 Jan 2026 21:56:18 GMT, Joe Darcy <darcy at openjdk.org> wrote:

>> Add comment describing why Math.fma uses BigDecimal.
>
> Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Respond to review feedback and add conclusion.

src/java.base/share/classes/java/lang/Math.java line 2381:

> 2379:     @IntrinsicCandidate
> 2380:     public static double fma(double a, double b, double c) {
> 2381:         // Implementation note: this method is intentionally coded in

The note seems currently structured as:

* Actual implementation design
* Hypothetical/alternative implementation design
* Performance context
* Actual implementation design ("-ilities")

The part suggesting how an alternative Java implementation could be made more performant seems counterproductive or at the least unnecessary.

I think the structure can be simplified as:

* Performance context
* Actual implementation design/"-ilities"

Here's a sketch intended to demonstrate the suggested stucture (needs work for correctness, grammar, etc.):


        // The Java implementation below will only be used where intrinsics
        // using hardware fma support is not available.
        // Therefore, simplicity, maintainability, and ease of testing
        // of the code is more important than direct performance.
        // The implementation is intentinally kept straightforward,
        // relying on BigDecimal for numerical computation.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29044#discussion_r2664155997