[VPlan] Get Cmp cost via getCostForRecipeWithOp for VPReplicateR (NFCI).

Use common getCostForRecipeWithOpcode to get the cost for ICmp/FCmp.

Author: fhahn

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -3045,12 +3045,13 @@ InstructionCost VPReplicateRecipe::computeCost(ElementCount VF,
   case Instruction::AShr:
   case Instruction::And:
   case Instruction::Or:
-  case Instruction::Xor: {
+  case Instruction::Xor:
+  case Instruction::ICmp:
+  case Instruction::FCmp:
     return *getCostForRecipeWithOpcode(getOpcode(), ElementCount::getFixed(1),
                                        Ctx) *
            (isSingleScalar() ? 1 : VF.getFixedValue());
   }
-  }
 
   return Ctx.getLegacyCost(UI, VF);
 }