Replace LoadNamedFieldPolymorphic with explicit branches.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 6be237351c5dafa7fa3e239f6aaedb47235832ea..708459168ea4f377172751c9b577f4b408438f43 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -2046,23 +2046,6 @@ LInstruction* LChunkBuilder::DoLoadNamedField(HLoadNamedField* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoLoadNamedFieldPolymorphic(
-    HLoadNamedFieldPolymorphic* instr) {
-  ASSERT(instr->representation().IsTagged());
-  if (instr->need_generic()) {
-    LOperand* obj = UseFixed(instr->object(), rax);
-    LLoadNamedFieldPolymorphic* result =
-        new(zone()) LLoadNamedFieldPolymorphic(obj);
-    return MarkAsCall(DefineFixed(result, rax), instr);
-  } else {
-    LOperand* obj = UseRegisterAtStart(instr->object());
-    LLoadNamedFieldPolymorphic* result =
-        new(zone()) LLoadNamedFieldPolymorphic(obj);
-    return AssignEnvironment(DefineAsRegister(result));
-  }
-}
-
-
 LInstruction* LChunkBuilder::DoLoadNamedGeneric(HLoadNamedGeneric* instr) {
   LOperand* object = UseFixed(instr->object(), rax);
   LLoadNamedGeneric* result = new(zone()) LLoadNamedGeneric(object);