RFR: 8320725: C2: Add "is_associative" flag for floating-point add-reduction [v3]

[Emanuel Peter]

On Mon, 18 Mar 2024 17:29:45 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> Bhavana Kilambi has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Naming changes: replace strict/non-strict with more technical terms
>
> src/hotspot/share/opto/vectornode.hpp line 240:
> 
>> 238:   //
>> 239:   // Other reductions are associative (do not need strict ordering).
>> 240:   virtual bool is_associative() const {
> 
> I think this flag may be badly named. The idea you want to express is not so much associativity, but whether such nodes should be treated as strictly ordered. It would be much less confusing to pick a name like ordered() because that describes what you want to the node to do.

I think you are right. Maybe we can use `ordered/unordered`. I just want to make sure we don't have too many synonyms (ordered, unordered, associative, strictly ordered, etc). But I guess associative and ordered is not exactly a synonym.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18034#discussion_r1533600124