RFR: 8366815: C2: Delay Mod/Div by constant transformation [v4]

[Quan Anh Mai]

On Mon, 15 Dec 2025 09:33:19 GMT, Hannes Greule <hgreule at openjdk.org> wrote:

>> The test cases show examples of code where `Value()` previously wasn't run because idealization took place before, resulting in less precise type analysis.
>> 
>> Please let me know what you think.
>
> Hannes Greule has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
> 
>  - Merge branch 'master' into delay-divmod-idealization
>  - review
>  - expand comments
>  - delay integral Div/Mod Ideal() until IGVN
>  - test

I reluctantly approve this PR, then :) Note that incremental inlining happens after IGVN so you still lose there.

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Marked as reviewed by qamai (Committer).

PR Review: https://git.openjdk.org/jdk/pull/27886#pullrequestreview-3577758443