RFR: 8325467: Support methods with many arguments in C2 [v15]

[Daniel Lundén]

On Mon, 7 Apr 2025 07:03:19 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Daniel Lundén has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Revise overlap comments for frequency of cases
>
> src/hotspot/share/opto/regmask.hpp line 40:
> 
>> 38: // stack slots used by BoxLockNodes. We reach this limit by, e.g., deeply
>> 39: // nesting synchronized statements in Java.
>> 40: const int BoxLockNode_slot_limit = 200;
> 
> Where does this number come from? I've added arbitrary constants like this, and sometimes it is hard to give a good justification. But at least writing down what was your thinking might help someone else if they come across it later. Do you have a sense how large it should be at least or at most?

It is indeed arbitrary (and should be very generous for all practical cases). We need a limit so that we can compute an upper bound for register mask sizes. I've updated the comment now, does it make more sense?

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PR Review Comment: https://git.openjdk.org/jdk/pull/20404#discussion_r2031473554