[DAG] DAGCombiner::tryStoreMergeOfLoads - remove unused StartAddress variable. NFCI.

Noticed in "initialization is never read" clang-tidy warning - the only StartAddress set/used is inside the load combine loop.

Author: RKSimon

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -17281,8 +17281,6 @@ bool DAGCombiner::tryStoreMergeOfLoads(SmallVectorImpl<MemOpLink> &StoreNodes,
   unsigned NumMemElts = MemVT.isVector() ? MemVT.getVectorNumElements() : 1;
   bool MadeChange = false;
 
-  int64_t StartAddress = StoreNodes[0].OffsetFromBase;
-
   // Look for load nodes which are used by the stored values.
   SmallVector<MemOpLink, 8> LoadNodes;
 
@@ -17350,7 +17348,7 @@ bool DAGCombiner::tryStoreMergeOfLoads(SmallVectorImpl<MemOpLink> &StoreNodes,
     unsigned LastLegalIntegerType = 1;
     bool isDereferenceable = true;
     bool DoIntegerTruncate = false;
-    StartAddress = LoadNodes[0].OffsetFromBase;
+    int64_t StartAddress = LoadNodes[0].OffsetFromBase;
     SDValue LoadChain = FirstLoad->getChain();
     for (unsigned i = 1; i < LoadNodes.size(); ++i) {
       // All loads must share the same chain.