RFR: 8325746: Refactor Loop Unswitching code [v8]

[Christian Hagedorn]

On Mon, 26 Feb 2024 09:55:00 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Christian Hagedorn has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fix If creation and add assert with test
>
> test/hotspot/jtreg/compiler/loopopts/TestBaseCountedEndLoopUnswitchCandidate.java line 31:
> 
>> 29:  * @run main/othervm -XX:CompileCommand=compileonly,compiler.loopopts.TestBaseCountedEndLoopUnswitchCandidate::test*
>> 30:  *                   -Xcomp -XX:LoopMaxUnroll=0 -XX:-UseLoopPredicate -XX:-RangeCheckElimination
>> 31:  *                   compiler.loopopts.TestBaseCountedEndLoopUnswitchCandidate
> 
> Might it make sense to have a run with fewer flags?

Do you mean an additional run? For the current run, we require the C2 flags in order to have loop peeling -> loop unswitching to get a `BaseCountedLoopEndNode`. We might be able to find a test that requires fewer flags but I think it's okay to opt for a simpler test + flags.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17842#discussion_r1502456501