RFR: 8373343: C2: verify AddP base input only set for heap addresses

[Roland Westrelin]

On Fri, 12 Dec 2025 23:45:16 GMT, Dean Long <dlong at openjdk.org> wrote:

>> The base input of `AddP` is expected to only be set for heap accesses
>> but I noticed some inconsistencies so I added an assert in the `AddP`
>> constructor and fixed issues that it caught. AFAFICT, the
>> inconsistencies shouldn't create issues.
>
> src/hotspot/share/opto/memnode.cpp line 4126:
> 
>> 4124:     Node* base = dest;
>> 4125:     if (phase->type(dest)->isa_oopptr() == nullptr) {
>> 4126:       base = phase->C->top();
> 
> How is this possible?  Aren't all arrays in the heap?

`isa_oopptr()` is non null for all oops, array and instance.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28769#discussion_r2619838306