RFR: 8351568: Improve source code documentation for PhaseCFG::insert_anti_dependences [v2]

[Roberto Castañeda Lozano]

On Thu, 8 May 2025 15:16:28 GMT, Daniel Lundén <dlunden at openjdk.org> wrote:

> Now simplified, does it look better?

Yes, thanks!

>> src/hotspot/share/opto/gcm.cpp line 779:
>> 
>>> 777:   ResourceArea* area = Thread::current()->resource_area();
>>> 778: 
>>> 779:   // Bookkeeping of possibly anti-dependent stores that we find outside of the
>> 
>> Suggestion:
>> 
>>   // Bookkeeping of possibly anti-dependent stores that we find below the
>
> Technically, "outside of" is more appropriate here, because the stores that we bookkeep are not necessarily dominated by ("below") early. Since the search starts from `initial_mem`, which can be in a much earlier block than early, stores that we bookkeep can also be above early, or on completely distinct control-flow paths that do not even go through early. But, you are correct that only stores below early matter in the end.

Thanks for the clarification. I think it would be good to add this note to the comment ("Note that stores in non_early_stores are not necessarily dominated by early. Since the search starts from ..." ).

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PR Review Comment: https://git.openjdk.org/jdk/pull/24926#discussion_r2081240077
PR Review Comment: https://git.openjdk.org/jdk/pull/24926#discussion_r2081235028