RFR: 8373591: C2: Fix the memory around some intrinsics nodes [v5]

[Quan Anh Mai]

On Fri, 30 Jan 2026 02:38:57 GMT, Dean Long <dlong at openjdk.org> wrote:

> This may be unrelated, but I checked to see if we treat `Op_EncodeISOArray` the same as `Op_StrCompressedCopy` everywhere. In two places in `ConnectionGraph::split_unique_types`, we treat them differently. For both we look at `in(MemNode::Memory)`, but for `Op_EncodeISOArray` we also look at `use->in(3)`. I don't understand this code well enough to decide if this a missing optimization or a correctness issue.

I believe it is because before this change, `EncodeISOArray` does not consume the memory of the destination like `StrCompressed`, so it may miss being pushed on the worklist. As a result, checking for `in(3)` ensures the node is visited. After this change, `EncodeISOArray` correctly consumes the memory of its destination, so that become unnecessary.

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PR Comment: https://git.openjdk.org/jdk/pull/28789#issuecomment-3821535212