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

[Christian Hagedorn]

On Mon, 26 May 2025 07:27:14 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> 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.

Yes, that matches what I remember. Maybe JDK-8319372 can now be reverted with JDK-8349479 in?

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/25396#discussion_r2106802008