RFR: 8342047: Create Template Assertion Predicates with Halt nodes only instead of uncommon traps [v2]

[Christian Hagedorn]

On Wed, 13 Nov 2024 10:37:49 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> src/hotspot/share/opto/loopPredicate.cpp line 362:
>> 
>>> 360: void PhaseIdealLoop::clone_parse_and_assertion_predicates_to_unswitched_loop(IdealLoopTree* loop, Node_List& old_new,
>>> 361:                                                                              IfProjNode*& true_path_loop_entry,
>>> 362:                                                                              IfProjNode*& false_path_loop_entry) {
>> 
>> Oh boy... passing pointers by reference... I suppose that was already here like this. Looks adventurous 🙈
>
> Maybe there should be some sort of `UnswitchingResult`, that has the projections and `old_new` mapping? That could then be passed as a result. What do you think? Can be a separate RFE of course.

Adventurous indeed. However, I'm planning to get rid of all this predicate code for Loop Unswitching anyway with [JDK-8344035](https://bugs.openjdk.org/browse/JDK-8344035). So, I guess it's fine to not further update the code at this point.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22040#discussion_r1840145772