[lworld] RFR: 8370450: [lworld] Alternate implementation of the substitutability test method [v4]

[Coleen Phillimore]

On Fri, 24 Oct 2025 15:05:07 GMT, Frederic Parain <fparain at openjdk.org> wrote:

>> This is an alternate version of the substitutability method.
>> To use it, add -Xshare:off -XX:+UseAltSubstitutabilityMethod to the command line of the Valhalla VM in preview mode.
>
> Frederic Parain has updated the pull request incrementally with one additional commit since the last revision:
> 
>   More fixes uggested in reviews

I had a couple of comments and a comment request.

src/hotspot/share/classfile/classFileParser.cpp line 5552:

> 5550:     //                           |               |
> 5551:     //                           --------------------- Pair of integer describing a segment of
> 5552:     //                                                 contiguous non-oop fields

Thanks for the ascii art - very helpful.

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Marked as reviewed by coleenp (Committer).

PR Review: https://git.openjdk.org/valhalla/pull/1695#pullrequestreview-3378048091
PR Review Comment: https://git.openjdk.org/valhalla/pull/1695#discussion_r2461398316