RFR: 8323220: Reassociate loop invariants involved in Cmps and Add/Subs [v9]

[Joshua Cao]

On Fri, 9 Feb 2024 06:13:52 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Joshua Cao has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Add correctness test for some random tests with random inputs
>
> test/hotspot/jtreg/compiler/loopopts/InvariantCodeMotionReassociateCmp.java line 37:
> 
>> 35:  */
>> 36: public class InvariantCodeMotionReassociateCmp {
>> 37:     private static final int size = 500;
> 
> You could even randomize size in a `@Setup` method, and pass it as another argument.

If I have a random size input, the loop is actually not a `CountedLoop`, and this transformation only applies to `CountedLoop`. I don't know all the details of `CountedLoop`, but this feels like a miss. Maybe `CountedLoop` can only handle loops with multiple exits of the limit is a constant.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17375#discussion_r1491848856