RFR: 8290892: C2: Intrinsify Reference.reachabilityFence [v19]

[Emanuel Peter]

On Thu, 30 Oct 2025 15:39:50 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> src/hotspot/share/opto/reachability.cpp line 89:
>> 
>>> 87: // In terms of dominance relation it can be formulated as "a referent has a user which is dominated by the redundant RF".
>>> 88: // Until loop opts are over, only RF nodes are considered as usages (controlled by rf_only flag).
>>> 89: static bool is_redundant_rf_helper(Node* ctrl, Node* referent, PhaseIdealLoop* phase, PhaseGVN& gvn, bool rf_only) {
>> 
>> Nit: `_helper` is fine if it is used as some internal method, i.e. only `is_redundant_rf` uses `is_redundant_rf_helper`. But it seems you are using it from different places. Can you find a better name?
>
> Can you write a comment what `ctrl`? Is it the `referent_ctrl`?

Ah no, in all cases I could see it was actually the `rf` itself, right? Why not give it a more specific name?

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PR Review Comment: https://git.openjdk.org/jdk/pull/25315#discussion_r2478599560