RFR: 8315066: Add unsigned bounds and known bits to TypeInt/Long [v65]
Quan Anh Mai
qamai at openjdk.org
Mon Jun 9 17:29:36 UTC 2025
> 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
-------------
Changes: https://git.openjdk.org/jdk/pull/17508/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17508&range=64
Stats: 2570 lines in 13 files changed: 2007 ins; 331 del; 232 mod
Patch: https://git.openjdk.org/jdk/pull/17508.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/17508/head:pull/17508
PR: https://git.openjdk.org/jdk/pull/17508
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