Replace LoadNamedFieldPolymorphic with explicit branches.

src/x64/lithium-x64.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 109 matching lines @@
   V(LazyBailout)                                \
   V(LoadContextSlot)                            \
   V(LoadExternalArrayPointer)                   \
   V(LoadFieldByIndex)                           \
   V(LoadFunctionPrototype)                      \
   V(LoadGlobalCell)                             \
   V(LoadGlobalGeneric)                          \
   V(LoadKeyed)                                  \
   V(LoadKeyedGeneric)                           \
   V(LoadNamedField)                             \
-  V(LoadNamedFieldPolymorphic)                  \
   V(LoadNamedGeneric)                           \
   V(MapEnumLength)                              \
   V(MathAbs)                                    \
   V(MathCos)                                    \
   V(MathExp)                                    \
   V(MathFloor)                                  \
   V(MathFloorOfDiv)                             \
   V(MathLog)                                    \
   V(MathMinMax)                                 \
   V(MathPowHalf)                                \
@@ skipping 1316 matching lines @@
     inputs_[0] = object;
   }
 
   LOperand* object() { return inputs_[0]; }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadNamedField, "load-named-field")
   DECLARE_HYDROGEN_ACCESSOR(LoadNamedField)
 };
 
 
-class LLoadNamedFieldPolymorphic: public LTemplateInstruction<1, 1, 0> {
- public:
-  explicit LLoadNamedFieldPolymorphic(LOperand* object) {
-    inputs_[0] = object;
-  }
-
-  DECLARE_CONCRETE_INSTRUCTION(LoadNamedField, "load-named-field-polymorphic")
-  DECLARE_HYDROGEN_ACCESSOR(LoadNamedFieldPolymorphic)
-
-  LOperand* object() { return inputs_[0]; }
-};
-
-
 class LLoadNamedGeneric: public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LLoadNamedGeneric(LOperand* object) {
     inputs_[0] = object;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadNamedGeneric, "load-named-generic")
   DECLARE_HYDROGEN_ACCESSOR(LoadNamedGeneric)
 
   LOperand* object() { return inputs_[0]; }
@@ skipping 1177 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::int
 
 #endif  // V8_X64_LITHIUM_X64_H_