RFR: 8362376: Use @Stable annotation in Java FDLIBM implementation

[John R Rose]

On Wed, 16 Jul 2025 04:53:04 GMT, Joe Darcy <darcy at openjdk.org> wrote:

> Add `@Stable` to the static final arrays used in the Java port of FDLIBM.

The effect of this PR is to make the affected array elements eligible for constant-folding by the JIT.

The contract of `@Stable` is private to the JDK, since it is a trusted annotation.  The trusted user promises not to change the array elements after the JIT might have observed them.

If we had a frozen (immutable) array feature in the JVM this PR could be formulated using frozen array constants.  But we are not there yet.

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PR Comment: https://git.openjdk.org/jdk/pull/26341#issuecomment-3079816223