Adjust extended reduction cost

Change-Id: Ie2795e0e5ebb0589146eaf07c752410e307a36e6

Author: nasherm

llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp

@@ -1794,6 +1794,7 @@ InstructionCost ARMTTIImpl::getExtendedReductionCost(
   case ISD::ADD:
     if (ST->hasMVEIntegerOps() && ValVT.isSimple() && ResVT.isSimple()) {
       std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(ValTy);
+
       // The legal cases are:
       //   VADDV u/s 8/16/32
       //   VADDLV u/s 32
@@ -1805,7 +1806,7 @@ InstructionCost ARMTTIImpl::getExtendedReductionCost(
           ((LT.second == MVT::v16i8 && RevVTSize <= 32) ||
            (LT.second == MVT::v8i16 && RevVTSize <= 32) ||
            (LT.second == MVT::v4i32 && RevVTSize <= 64)))
-        return ST->getMVEVectorCostFactor(CostKind) * LT.first;
+        return 3 * ST->getMVEVectorCostFactor(CostKind) * LT.first;
     }
     break;
   default: