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

[Joshua Cao]

On Fri, 9 Feb 2024 06:14:29 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 54:
> 
>> 52:             // Reassociate to `inv2 - inv1 == i`
>> 53:             if (inv1 + i == inv2) {
>> 54:                 blackhole();
> 
> If you return instead of break, do you still need the `blackhole`?

No we don't need it. But it would feel strange to have a loop with nothing in it other than comparisons of an induction variable.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17375#discussion_r1491837953