RFR: 8349479: C2: when a Type node becomes dead, make CFG path that uses it unreachable [v2]

[Roland Westrelin]

On Thu, 20 Mar 2025 10:00:37 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Roland Westrelin has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   review
>
> src/hotspot/share/opto/node.cpp line 3100:
> 
>> 3098:     loop->register_new_node(frame, igvn->C->start());
>> 3099:   }
>> 3100:   Node* halt = new HaltNode(c, frame, "dead path discovered by TypeNode");
> 
> The more info we can attach to the `HaltNode`, the better. It would make debugging easier if it is ever hit.

Is there anything in particular you think makes sense adding?

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PR Review Comment: https://git.openjdk.org/jdk/pull/23468#discussion_r2018583157