RFR: JDK-8287284: C2: loop optimization performs split_thru_phi infinitely many times [v3]

[Tobias Holenstein]

On Tue, 24 Oct 2023 10:26:11 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

>> Tobias Holenstein has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   remove useless loop
>
> src/hotspot/share/opto/loopopts.cpp line 236:
> 
>> 234:   assert(region->is_Loop(), "region should be a loop");
>> 235:   IdealLoopTree* n_loop_tree = get_loop(region);
>> 236:   for (uint j = 1; j < n->req(); j++) {
> 
> Why do you need this loop at all? Wouldn't it be sufficient to just check `x_loop_tree->is_member(n_loop_tree)`?

you are right! I changed it

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PR Review Comment: https://git.openjdk.org/jdk/pull/15536#discussion_r1370023587