RFR: 8315066: Add unsigned bounds and known bits to TypeInt/Long [v54]

[Quan Anh Mai]

On Thu, 1 May 2025 10:39:57 GMT, Quan Anh Mai <qamai at openjdk.org> wrote:

>> If this is  indeed a bug, we need a test case to catch it :)
>
> No, the subset relation is only reversed in the set of all `CT` instances. In the overall `Type` hierarchy it is still the same, we are trying to find the union of the arguments. If you try to change it to `return dual ? t2 : i1` you would be hit with `=== Meet Not Symmetric ===` errors everywhere :) Similarly, that is why when the 2 arguments are of different kind the result is always `Type::BOTTOM`.

I have also added an explanation for this function.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17508#discussion_r2070142995