RFR: 8354383: C2: enable sinking of Type nodes out of loop [v2]

[Roland Westrelin]

On Fri, 23 May 2025 07:12:53 GMT, Christian Hagedorn <chagedorn 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/loopopts.cpp line 1688:
> 
>> 1686:       !n->is_OpaqueInitializedAssertionPredicate() &&
>> 1687:       !n->is_OpaqueTemplateAssertionPredicate() &&
>> 1688:       !n->is_Type()) {
> 
> I cannot remember exactly, how often was it a problem without JDK-8349479? If it was more common, we might want to only allow it when `KillPathsReachableByDeadTypeNode` is set.

I made that change.
As far as I remember, the logic removed by JDK-8319372 played a key role in those failures. Not sure if any were still reproducible after than one.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25396#discussion_r2106726011