RFR: 8355488: Add stress mode for C2 loop peeling [v3]

[Tobias Hartmann]

On Fri, 16 May 2025 07:53:41 GMT, Marc Chevalier <mchevalier at openjdk.org> wrote:

>> src/hotspot/share/opto/loopTransform.cpp line 522:
>> 
>>> 520:       loop_head->_peeling_opportunities_count++;
>>> 521:       // In case of stress, let's just pick randomly...
>>> 522:       return phase->C->random() % 2 == 0 ? estimate : 0;
>> 
>> Suggestion:
>> 
>>       return ((phase->C->random() % 2) == 0) ? estimate : 0;
>
> Done. But does that really helps you? To me it's just more confusing. It looks like "I put parentheses because it will associate in a surprising way", and then the most normal things comes. I often wonder whether the parentheses are misplaced, or whether there is something subtle I don't get.
> But anyway, parentheses are in!

I think it just helps readability because you don't need to think about operator precedence. But it surely is personal preference.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25140#discussion_r2092590771