MIPS: Add HLoadRoot hydrogen instruction.

src/mips/lithium-mips.h

Index: src/mips/lithium-mips.h
diff --git a/src/mips/lithium-mips.h b/src/mips/lithium-mips.h
index 3ab8f37a15fced123b33c020c785a9c4a4a47462..cfc0909e9d0b1c32933cc2dd0d43d3aa916ec61e 100644
--- a/src/mips/lithium-mips.h
+++ b/src/mips/lithium-mips.h
@@ -119,6 +119,7 @@ class LCodeGen;
   V(LazyBailout)                                \
   V(LoadContextSlot)                            \
   V(LoadExternalArrayPointer)                   \
+  V(LoadRoot)                                   \
   V(LoadFieldByIndex)                           \
   V(LoadFunctionPrototype)                      \
   V(LoadGlobalCell)                             \
@@ -1559,6 +1560,15 @@ class LLoadFunctionPrototype V8_FINAL : public LTemplateInstruction<1, 1, 0> {
 };
 
 
+class LLoadRoot V8_FINAL : public LTemplateInstruction<1, 0, 0> {
+ public:
+  DECLARE_CONCRETE_INSTRUCTION(LoadRoot, "load-root")
+  DECLARE_HYDROGEN_ACCESSOR(LoadRoot)
+
+  Heap::RootListIndex index() const { return hydrogen()->index(); }
+};
+
+
 class LLoadExternalArrayPointer V8_FINAL
     : public LTemplateInstruction<1, 1, 0> {
  public: