RFR: 8323220: Reassociate loop invariants involved in Cmps and Add/Subs [v3]

[Xin Liu]

On Sat, 20 Jan 2024 08:32:10 GMT, Xin Liu <xliu at openjdk.org> wrote:

>> Joshua Cao has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Assert for n2. Variables for n1/n2 opcode. More concise comments.
>>   Overflow/random tests
>
> src/hotspot/share/opto/loopTransform.cpp line 356:
> 
>> 354:   }
>> 355: 
>> 356:   bool is_int = n2->bottom_type()->isa_int() != nullptr;
> 
> I guess you change to n2 because n1 may be CmpI/L. 
> I think it still works because TypeInt::CC is still isa_int(). or we add a comment to make it more clear?

Sorry, I think you're right. we have to use 'n2' here. 
we need to distinct CmpI and CmpL. TypeInt::CC can't.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17375#discussion_r1460304622