Split up HLoadNamedField and HStoreNamedField.

src/hydrogen-check-elimination.cc

 // Copyright 2013 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 250 matching lines @@
   void ReduceCheckHeapObject(HCheckHeapObject* instr) {
     if (FindMaps(instr->value()->ActualValue()) != NULL) {
       // If the object has known maps, it's definitely a heap object.
       instr->DeleteAndReplaceWith(instr->value());
       INC_STAT(removed_cho_);
     }
   }
 
   void ReduceStoreNamedField(HStoreNamedField* instr) {
     HValue* object = instr->object()->ActualValue();
-    if (instr->has_transition()) {
-      // This store transitions the object to a new map.
-      Kill(object);
-      Insert(object, MapConstant(instr->transition()));
-    } else if (IsMapAccess(instr->access())) {
+    if (IsMapAccess(instr->access())) {
       // This is a store directly to the map field of the object.
       Kill(object);
       if (!instr->value()->IsConstant()) return;
       Insert(object, MapConstant(instr->value()));
     } else {
       // If the instruction changes maps, it should be handled above.
       CHECK(!instr->CheckGVNFlag(kChangesMaps));
     }
   }
 
@@ skipping 181 matching lines @@
   void Apply(HCheckTable* table) {
     if (maps_stored_) {
       // Uncontrollable map modifications; kill everything.
       table->Kill();
       return;
     }
 
     // Kill maps for each store contained in these effects.
     for (int i = 0; i < stores_.length(); i++) {
       HStoreNamedField* s = stores_[i];
-      if (table->IsMapAccess(s->access()) || s->has_transition()) {
+      if (table->IsMapAccess(s->access())) {
         table->Kill(s->object()->ActualValue());
       }
     }
   }
 
   // Union these effects with the other effects.
   void Union(HCheckMapsEffects* that, Zone* zone) {
     maps_stored_ |= that->maps_stored_;
     for (int i = 0; i < that->stores_.length(); i++) {
       stores_.Add(that->stores_[i], zone);
@@ skipping 39 matching lines @@
   PRINT_STAT(removed_cho);
   PRINT_STAT(narrowed);
   PRINT_STAT(loads);
   PRINT_STAT(empty);
   PRINT_STAT(compares_true);
   PRINT_STAT(compares_false);
   PRINT_STAT(transitions);
 }
 
 } }  // namespace v8::internal