RFR: 8315066: Add unsigned bounds and known bits to TypeInt/Long [v65]

[Quan Anh Mai]

On Mon, 9 Jun 2025 17:29:36 GMT, Quan Anh Mai <qamai at openjdk.org> wrote:

>> Hi,
>> 
>> This patch adds unsigned bounds and known bits constraints to TypeInt and TypeLong. This opens more transformation opportunities in an elegant manner as well as helps avoid some ad-hoc rules in Hotspot.
>> 
>> In general, a `TypeInt/Long` represents a set of values `x` that satisfies: `x s>= lo && x s<= hi && x u>= ulo && x u<= uhi && (x & zeros) == 0 && (x & ones) == ones`. These constraints are not independent, e.g. an int that lies in [0, 3] in signed domain must also lie in [0, 3] in unsigned domain and have all bits but the last 2 being unset. As a result, we must canonicalize the constraints (tighten the constraints so that they are optimal) before constructing a `TypeInt/Long` instance.
>> 
>> This is extracted from #15440 , node value transformations are left for later PRs. I have also added unit tests to verify the soundness of constraint normalization.
>> 
>> Please kindly review, thanks a lot.
>> 
>> Testing
>> 
>> - [x] GHA
>> - [x] Linux x64, tier 1-4
>
> Quan Anh Mai has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 83 commits:
> 
>  - Merge branch 'master' into unsignedbounds
>  - add more intn_t tests
>  - Emanuel's reviews
>  - alignment wording
>  - refinement
>  - refine the cases where there does not exist a result
>  - add some more sanity static_asserts
>  - intn_t refinements
>  - Emanuel's reviews
>  - Emanuel's reviews
>  - ... and 73 more: https://git.openjdk.org/jdk/compare/cae1fd33...ad6ac7cb

I think all the tests have passed, I will integrate this PR.

Thank you a lot for reviewing this PR. Especially, thanks @eme64 for your rigorous reviews and valuable suggestions, it helps a lot in shaping this PR in a better manner.

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PR Comment: https://git.openjdk.org/jdk/pull/17508#issuecomment-2968436381