[llvm] [SLP][REVEC] Fix cost model for getBuildVectorCost with FixedVectorType ScalarTy. (PR #110073)

[Alexey Bataev via llvm-commits]

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@@ -9198,10 +9198,18 @@ class BoUpSLP::ShuffleCostEstimator : public BaseShuffleAnalysis {
       bool NeedShuffle =
           count(VL, *It) > 1 &&
           (VL.front() != *It || !all_of(VL.drop_front(), IsaPred<UndefValue>));
-      if (!NeedShuffle)
+      if (!NeedShuffle) {
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alexey-bataev wrote:

A test is required

https://github.com/llvm/llvm-project/pull/110073