RFR: 8367341: C2: apply KnownBits and unsigned bounds to And / Or operations

[Quan Anh Mai]

On Mon, 13 Oct 2025 12:30:11 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Hmm, we also have the third class `TypeIntPrototype`. Do you think we really need all 3 classes?
>
> Ah, I suppose `TypeIntMirror` is always canonicalized from `TypeIntPrototype`, in the constructor?

Yah `TypeIntPrototype` is a prototype and can contain arbitrary field values while `TypeInt` and `TypeIntMirror` are canonicalized. It is sad that `TypeInt` is heavily coupled with the `Type` infrastructure, so making a mirror that does not suffer from one is necessary. I tried messing around with the `Type` allocator but it seems error-prone since we have several `TypeInt` instances coming from a different allocator (`TypeInt::ZERO` for example). As a result, having a separate type prevents these errors (`TypeIntMirror::INT` won't compile).

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PR Review Comment: https://git.openjdk.org/jdk/pull/27618#discussion_r2431569822