Implement optional turbofan UnalignedLoad and UnalignedStore operators

src/compiler/machine-operator-reducer.cc

Index: src/compiler/machine-operator-reducer.cc
diff --git a/src/compiler/machine-operator-reducer.cc b/src/compiler/machine-operator-reducer.cc
index 19ea06205361fef01f29d5a2dc22e6067de10554..3ff3b5661984f90c0f6dc77e09ab0644cbfb6d4b 100644
--- a/src/compiler/machine-operator-reducer.cc
+++ b/src/compiler/machine-operator-reducer.cc
@@ -438,6 +438,7 @@ Reduction MachineOperatorReducer::Reduce(Node* node) {
     case IrOpcode::kFloat64InsertHighWord32:
       return ReduceFloat64InsertHighWord32(node);
     case IrOpcode::kStore:
+    case IrOpcode::kUnalignedStore:
       return ReduceStore(node);
     case IrOpcode::kFloat64Equal:
     case IrOpcode::kFloat64LessThan:
@@ -677,9 +678,21 @@ Reduction MachineOperatorReducer::ReduceTruncateFloat64ToInt32(Node* node) {
 
 
 Reduction MachineOperatorReducer::ReduceStore(Node* node) {
-  MachineRepresentation const rep =
-      StoreRepresentationOf(node->op()).representation();
+  MachineRepresentation rep;
   Node* const value = node->InputAt(2);
+
+  switch (node->opcode()) {
+    case IrOpcode::kStore:
+      rep = StoreRepresentationOf(node->op()).representation();
+      break;
+    case IrOpcode::kUnalignedStore:
+      rep = UnalignedStoreRepresentationOf(node->op());
+      break;
+    default:
+      UNREACHABLE();
+      break;
+  }
+
   switch (value->opcode()) {
     case IrOpcode::kWord32And: {
       Uint32BinopMatcher m(value);