[PATCH] D121044: [X86][TTI] `getReplicationShuffleCost()`: account for deduplication

[Roman Lebedev via Phabricator via llvm-commits]

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Let's take a look at:
https://godbolt.org/z/4f6bv69hc

Even though it would seem that we need 4 shuffles there,
we only need two, because the replication factor is 2x the vector size,
so half of the vectors can be materialized via a `mov`e.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D121044

Files:
  llvm/lib/Target/X86/X86TargetTransformInfo.cpp
  llvm/test/Analysis/CostModel/X86/shuffle-replication-i64.ll

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