[llvm] [LoopVectorize] Add cost of generating tail-folding mask to the loop (PR #130565)

[Paul Walker via llvm-commits]

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@@ -801,6 +801,22 @@ InstructionCost VPInstruction::computeCost(ElementCount VF,
                                   cast<VectorType>(VectorTy), Mask,
                                   Ctx.CostKind, VF.getKnownMinValue() - 1);
   }
+  case VPInstruction::ActiveLaneMask: {
+    Type *Arg0Ty = Ctx.Types.inferScalarType(getOperand(0));
+    Type *Arg1Ty = Ctx.Types.inferScalarType(getOperand(1));
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paulwalker-arm wrote:

Given `get.active.lane.mask` requires both parameters to be the same type, do we need to calculate `Arg1Ty`?

https://github.com/llvm/llvm-project/pull/130565