RFR: 8326962: C2 SuperWord: cache VPointer [v4]

[Christian Hagedorn]

On Tue, 2 Apr 2024 16:12:23 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> src/hotspot/share/opto/vectorization.cpp line 184:
>> 
>>> 182: }
>>> 183: 
>>> 184: void VLoopPointers::compute_and_cache() {
>> 
>> Could be split into something like:
>> 
>> allocate_pointer_memory(); 
>> initialize_pointers();
>> trace_pointers();
>> 
>> where allocate_pointer_memory():
>> number_of_pointers = compute_number_of_pointers();
>> uint bytes = number_of_pointers * sizeof(VPointer);
>> _pointers = (VPointer*)_arena->Amalloc(bytes);
>
> With the new `for_each_mem`, the code is already much easier to read. I don't know if splitting it further would really help now?

That's already better!

My general take on that is when I see:

// Do x
// Do y
// Do z

it suggests that it should actually be

x();
y();
z();

But that's just my personal preference :-)

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PR Review Comment: https://git.openjdk.org/jdk/pull/18577#discussion_r1548995281