[lworld] RFR: 8332406: [lworld] C2: Turn flat in array property into proper lattice in type system to address remaining issues [v2]

[Christian Hagedorn]

On Mon, 8 Dec 2025 09:09:01 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

>> Christian Hagedorn has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   update description
>
> src/hotspot/share/opto/type.cpp line 6272:
> 
>> 6270: 
>> 6271: uint TypeInstKlassPtr::hash(void) const {
>> 6272:   return klass()->hash() + TypeKlassPtr::hash() + (uint)_flat_in_array;
> 
> You might want to use `static_cast<uint>` here, similar to `TypeInstPtr::hash`.

Right, updated!

> src/hotspot/share/opto/type.hpp line 1331:
> 
>> 1329:   virtual bool maybe_null() const { return meet_ptr(Null) == ptr(); }
>> 1330: 
>> 1331:   static FlatInArray dual_flat_in_array(FlatInArray flat_in_array) {
> 
> I think this should be a non-static method so that you can access the `_flat_in_array` field directly.

Good idea! Updated.

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1774#discussion_r2597884162
PR Review Comment: https://git.openjdk.org/valhalla/pull/1774#discussion_r2597884125