Fix polymorphic store.

src/hydrogen.cc

 // 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 7243 matching lines @@
                      previous_representation)) {
         break;
       }
     }
 
     if (types->length() == count) {
       AddInstruction(new(zone()) HCheckNonSmi(object));
       AddInstruction(HCheckMaps::New(object, types, zone()));
       HInstruction* instr = BuildStoreNamedField(
           object, name, value, map, &lookup);
+      AddInstruction(instr);
       instr->set_position(expr->position());
-      return ast_context()->ReturnInstruction(instr, expr->id());
+      // The HSimulate for the store should not see the stored value in
+      // effect contexts (it is not materialized at expr->id() in the
+      // unoptimized code).
+      if (instr->HasObservableSideEffects()) {
+        if (ast_context()->IsEffect()) {
+          AddSimulate(expr->id(), REMOVABLE_SIMULATE);
+        } else {
+          Push(value);
+          AddSimulate(expr->id(), REMOVABLE_SIMULATE);
+          Drop(1);
+        }
+      }
+      return ast_context()->ReturnValue(value);
     }
   }
 
   // TODO(ager): We should recognize when the prototype chains for different
   // maps are identical. In that case we can avoid repeatedly generating the
   // same prototype map checks.
   int count = 0;
   HBasicBlock* join = NULL;
   for (int i = 0; i < types->length() && count < kMaxStorePolymorphism; ++i) {
     Handle<Map> map = types->at(i);
@@ skipping 5076 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal