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

[Emanuel Peter]

On Mon, 3 Nov 2025 22:32:29 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> src/hotspot/share/opto/loopnode.cpp line 5119:
>> 
>>> 5117:   if (stop_early) {
>>> 5118:     assert(do_expensive_nodes || do_optimize_reachability_fences, "why are we here?");
>>> 5119:     if (do_optimize_reachability_fences && optimize_reachability_fences()) {
>> 
>> Can you explain why you call `optimize_reachability_fences` here and also below?
>
> The intention is to optimize RF nodes irrespective of whether loop optimizations are performed or not. (It mimics similar logic for expensive nodes.)

Can you make that explicit with a code comment please?

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PR Review Comment: https://git.openjdk.org/jdk/pull/25315#discussion_r2489216359