Added non observable side effects scope and removed unnecessary calls to AddSimulate.

src/hydrogen-instructions.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 810 matching lines @@
     // it will deoptimize if result does not fit into signed integer range.
     // HGraph::ComputeSafeUint32Operations is responsible for setting this
     // flag.
     kUint32,
     // If a phi is involved in the evaluation of a numeric constraint the
     // recursion can cause an endless cycle: we use this flag to exit the loop.
     kNumericConstraintEvaluationInProgress,
     // This flag is set to true after the SetupInformativeDefinitions() pass
     // has processed this instruction.
     kIDefsProcessingDone,
+    kHasNoObservableSideEffects,
     kLastFlag = kIDefsProcessingDone
   };
 
   STATIC_ASSERT(kLastFlag < kBitsPerInt);
 
   static const int kChangesToDependsFlagsLeftShift = 1;
 
   static GVNFlag ChangesFlagFromInt(int x) {
     return static_cast<GVNFlag>(x * 2);
   }
@@ skipping 157 matching lines @@
   void ClearGVNFlag(GVNFlag f) { gvn_flags_.Remove(f); }
   bool CheckGVNFlag(GVNFlag f) const { return gvn_flags_.Contains(f); }
   void SetAllSideEffects() { gvn_flags_.Add(AllSideEffectsFlagSet()); }
   void ClearAllSideEffects() {
     gvn_flags_.Remove(AllSideEffectsFlagSet());
   }
   bool HasSideEffects() const {
     return gvn_flags_.ContainsAnyOf(AllSideEffectsFlagSet());
   }
   bool HasObservableSideEffects() const {
-    return gvn_flags_.ContainsAnyOf(AllObservableSideEffectsFlagSet());
+    return !CheckFlag(kHasNoObservableSideEffects) &&
+        gvn_flags_.ContainsAnyOf(AllObservableSideEffectsFlagSet());
   }
 
   GVNFlagSet DependsOnFlags() const {
     GVNFlagSet result = gvn_flags_;
     result.Intersect(AllDependsOnFlagSet());
     return result;
   }
 
   GVNFlagSet SideEffectFlags() const {
     GVNFlagSet result = gvn_flags_;
@@ skipping 5411 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_