RFR: 8318446: C2: optimize stores into primitive arrays by combining values into larger store [v11]

[Emanuel Peter]

On Fri, 23 Feb 2024 06:31:32 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

>> Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   make it happen in post_loop_opts
>
> src/hotspot/share/opto/memnode.cpp line 2860:
> 
>> 2858:   Node* new_mem  = first->in(MemNode::Memory);
>> 2859:   Node* new_adr  = first->in(MemNode::Address);
>> 2860:   const TypePtr* atp = TypeRawPtr::BOTTOM;
> 
> What does C2 prevent from moving a load from one of the array elements to above the raw store, assuming they are independent?

I don't know. I have added a test now for that, but probably need more tests.
@vnkozlov @rwestrel  do you think I need to do something about this?

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PR Review Comment: https://git.openjdk.org/jdk/pull/16245#discussion_r1500818856