Increase coverage of global loads in optimized code

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
===================================================================
--- src/x64/lithium-x64.cc	(revision 7468)
+++ src/x64/lithium-x64.cc	(working copy)
@@ -1717,14 +1717,21 @@
 }
 
 
-LInstruction* LChunkBuilder::DoLoadGlobal(HLoadGlobal* instr) {
-  LLoadGlobal* result = new LLoadGlobal;
+LInstruction* LChunkBuilder::DoLoadGlobalCell(HLoadGlobalCell* instr) {
+  LLoadGlobalCell* result = new LLoadGlobalCell;
   return instr->check_hole_value()
       ? AssignEnvironment(DefineAsRegister(result))
       : DefineAsRegister(result);
 }
 
 
+LInstruction* LChunkBuilder::DoLoadGlobalGeneric(HLoadGlobalGeneric* instr) {
+  LOperand* global_object = UseFixed(instr->global_object(), rax);
+  LLoadGlobalGeneric* result = new LLoadGlobalGeneric(global_object);
+  return MarkAsCall(DefineFixed(result, rax), instr);
+}
+
+
 LInstruction* LChunkBuilder::DoStoreGlobal(HStoreGlobal* instr) {
   LStoreGlobal* result = new LStoreGlobal(UseRegister(instr->value()),
                                           TempRegister());