[turbofan] Add checked load/store operators.

src/compiler/simplified-lowering.h

Index: src/compiler/simplified-lowering.h
diff --git a/src/compiler/simplified-lowering.h b/src/compiler/simplified-lowering.h
index 0e8d5aa7226922f3a4153ea8775b2573aecfb6e6..852ac7eaa082c3e8b08ef7be60a493182d3e3f0b 100644
--- a/src/compiler/simplified-lowering.h
+++ b/src/compiler/simplified-lowering.h
@@ -14,6 +14,10 @@ namespace v8 {
 namespace internal {
 namespace compiler {
 
+// Forward declarations.
+class RepresentationChanger;
+
+
 class SimplifiedLowering FINAL {
  public:
   explicit SimplifiedLowering(JSGraph* jsgraph) : jsgraph_(jsgraph) {}
@@ -26,7 +30,10 @@ class SimplifiedLowering FINAL {
   void DoStoreField(Node* node);
   // TODO(turbofan): The output_type can be removed once the result of the
   // representation analysis is stored in the node bounds.
-  void DoLoadElement(Node* node, MachineType output_type);
+  void DoLoadBuffer(Node* node, MachineType output_type,
+                    RepresentationChanger* changer);
+  void DoStoreBuffer(Node* node);
+  void DoLoadElement(Node* node);
   void DoStoreElement(Node* node);
   void DoStringAdd(Node* node);
   void DoStringEqual(Node* node);