[PATCH] D154157: [LV] Cost model for out-of-loop reductions

[Evgeniy via Phabricator via llvm-commits]

ebrevnov added a comment.
Herald added a subscriber: wangpc.

I support Florian's suggestion. We better take reduction overhead into account the same way as we did for runtime checks.
Today's cost model is very limited in its ability to predict the overhead which comes with the vectorization. For example, the overhead of the scalar epilogue loop is simply ignored. I think, one day we should generalize the cost model so that vectorization overhead is integral part of the model itself rather than a follow up "fix up".


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https://reviews.llvm.org/D154157