RFR: 8302652: [SuperWord] Reduction should happen after loop, when possible [v5]

[Emanuel Peter]

On Fri, 12 May 2023 07:29:16 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   use is_counted and is_innermost
>
> src/hotspot/share/opto/loopopts.cpp line 4272:
> 
>> 4270:       Node* last_vector_accumulator = current->in(1);
>> 4271:       Node* vector_input            = current->in(2);
>> 4272:       VectorNode* vector_accumulator = current->make_normal_vector_op(last_vector_accumulator, vector_input, vec_t);
> 
> Should this be guarded by a safe _Matcher::match_rule_supported_vector_ .

Right, makes sense. I'd have to guard before any transformations take place. So maybe I'll have a second method:
`UnorderedReductionNode::make_normal_vector_op_supported`, and use `Matcher::match_rule_supported_vector` inside.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13056#discussion_r1192023372