[PATCH] D123400: [LoopCacheAnalysis] Consider dimension depth of the subscript reference when calculating cost

[Ehsan Amiri via Phabricator via llvm-commits]

amehsan added a comment.

Hi Bardia

Thanks for your work on this. While I keep an eye on the work on loop interchage, I don't have enough details in mind to give a detailed review here. Just two things occured to me that may be worthwhile to mention

1. Boiling down various parameters to one final "cost" value has a disadvantage. In fact we discussed this with @congzhe as the first solution, but we discarded it because essentially you lose some informaiton when you boil everything down to one number. The reason that Congzhe decided to go with a two component cost was that extra detail, carries more useful information and helps to make more accurate decision. Now this was a theoretical concern and I am not sure if in practice it holds or not. But that is the background on congzhe's work.



1. Wouldn't it be more appropriate to continue discussion on congzhe's patch rather than posting a parallel patch to address the same problem? I think that will be more constructive given congzhe has already identified the problem, investigated some solutions and developed a patch? I suggest we continue the discussion, as review comments on his patch. Once there is an agreement on the cost function, Congzhe can update the patch (assuming it is needed) to reflect the agreed upon solution.




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https://reviews.llvm.org/D123400