RFR: 8315066: Add unsigned bounds and known bits to TypeInt/Long [v2]

[Quan Anh Mai]

On Mon, 28 Aug 2023 15:37:53 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. The new constraints are applied to identity and value calls of the common nodes (Add, Sub, L/R/URShift, And, Or, Xor, bit counting, Cmp, Bool, ConvI2L/L2I), the detailed ideas for each node will be presented below.
>> 
>> 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) == 0`. 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 normalize the constraints (tighten the constraints so that they are optimal) before constructing a `TypeInt/Long` instance.
>> 
>> Please kindly review, thanks very much.
>> 
>> Testing
>> 
>> - [x] GHA
>> - [x] Linux x64, tier 1-4
>
> Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:
> 
>   typo

Can I have a review for this patch, please.

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PR Comment: https://git.openjdk.org/jdk/pull/15440#issuecomment-1725200959