RFR: 8371536: C2: VerifyIterativeGVN should assert on first detected failure [v6]

[Emanuel Peter]

On Thu, 18 Dec 2025 15:41:22 GMT, Benoît Maillard <bmaillard at openjdk.org> wrote:

>> src/hotspot/share/opto/phaseX.cpp line 1839:
>> 
>>> 1837:   // return and finally hit the assert in PhaseIterGVN::verify_optimize to get
>>> 1838:   // a more meaningful message
>>> 1839:   _table.hash_delete(n);
>> 
>> Looks like an unrelated change. Why are you adding it now?
>
> This is here from the first version of the PR. From the initial PR descriptiom:
> 
>> In summary, this PR brings the following changes:
>> ...
>> - Avoid confusing `Need to remove from hash before changing edges` assert messages by removing the verified node from the hash table before attempting to optimize the node in question.
> 
> I think it's relevant to have it here, don't you think so?

Ok, sure. Sounds good to me :)

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PR Review Comment: https://git.openjdk.org/jdk/pull/28295#discussion_r2631798421