On Mon, 14 Apr 2025 14:47:59 GMT, Per Minborg <pminb...@openjdk.org> wrote:
> This PR proposes to add the `@Stable` annotation to `j.l.String.hash` and > `j.l.String.hashIsZero`. This means the VM can trust these fields to never > change which enables constant folding optimizations. > > This PR is tested in tier1, tier2, tier3, and tier4 which all pass. As discussed, we could integrate the current PR and then revisit `j.l.String` later. I have raised a new issue for this: https://bugs.openjdk.org/browse/JDK-8354777 The output of the attached benchmark in the `777 issue confirms zero hash values are not constant folded: Benchmark Mode Cnt Score Error Units StringHashCodeStatic.empty avgt 15 5.774 ± 0.143 ns/op StringHashCodeStatic.nonZero avgt 15 0.571 ± 0.012 ns/op StringHashCodeStatic.zero avgt 15 4.039 ± 0.038 ns/op Unless no one objects within a day or so, I will integrate this PR. ------------- PR Comment: https://git.openjdk.org/jdk/pull/24625#issuecomment-2808627521
