[llvm] [VPlan] Compute cost of replicating calls in VPlan. (NFCI) (PR #154291)

[Florian Hahn via llvm-commits]

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@@ -3017,8 +3010,43 @@ InstructionCost VPReplicateRecipe::computeCost(ElementCount VF,
     SmallVector<Type *, 4> Tys;
     for (VPValue *ArgOp : drop_end(operands()))
       Tys.push_back(Ctx.Types.inferScalarType(ArgOp));
+
     Type *ResultTy = Ctx.Types.inferScalarType(this);
-    return Ctx.TTI.getCallInstrCost(CalledFn, ResultTy, Tys, Ctx.CostKind);
+    InstructionCost ScalarCallCost =
+        Ctx.TTI.getCallInstrCost(CalledFn, ResultTy, Tys, Ctx.CostKind);
+    if (isSingleScalar())
+      return ScalarCallCost;
+
+    if (VF.isScalable())
+      return InstructionCost::getInvalid();
+
+    // Compute the cost of scalarizing the result and operands if needed.
+    InstructionCost ScalarizationCost = 0;
+    if (VF.isVector()) {
+      if (!ResultTy->isVoidTy()) {
+        for (Type *VectorTy : getContainedTypes(toVectorizedTy(ResultTy, VF))) {
+          ScalarizationCost += Ctx.TTI.getScalarizationOverhead(
+              cast<VectorType>(VectorTy), APInt::getAllOnes(VF.getFixedValue()),
+              /*Insert=*/true,
+              /*Extract=*/false, Ctx.CostKind);
+        }
+      }
+      // Skip operands that do not require extraction/scalarization and do not
+      // incur any overhead.
+      SmallVector<Type *> Tys;
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fhahn wrote:

Used clear for now, thanks!

https://github.com/llvm/llvm-project/pull/154291