RFR: 8363996: Obsolete UseCompressedClassPointers [v4]

[Thomas Stuefe]

On Mon, 9 Feb 2026 11:11:24 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> src/hotspot/share/oops/oop.inline.hpp line 157:
>> 
>>> 155:   assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
>>> 156:   assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
>>> 157:   _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
>> 
>> We might have to reconsider if we need to maintain the`union _metadata`
>
> Right you are. We only should need narrowKlass now, even on 32-bit.

Fixed: removed union, replaced with narrowKlass

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PR Review Comment: https://git.openjdk.org/jdk/pull/28366#discussion_r2782264128