[PATCH] D55452: [CostModel][X86] Teach getArithmeticReductionCost to properly cost the shuffles needed for a PairWise reduction before we reach a legal type. And remove one shuffle from the end of the reduction.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added a comment.

I don't see a single test, where you could run into the described problem. And I think this patch should be split into 2 parts: 1 for the first part with the types and another one for extra cost.
Also, I think that the problem with the incorrect cost for X86 is the problem of the X86 TTI implementation rather than the problem of the generic solution.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D55452/new/

https://reviews.llvm.org/D55452