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

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 6a74ec8b35ac649302914da2d9b6a4c5ec8af4e4..7acec8bcd5ebc3e2e0757d312ee591f5e5174e72 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -828,6 +828,7 @@ class HValue: public ZoneObject {
     // This flag is set to true after the SetupInformativeDefinitions() pass
     // has processed this instruction.
     kIDefsProcessingDone,
+    kHasNoObservableSideEffects,
     kLastFlag = kIDefsProcessingDone
   };
 
@@ -1005,7 +1006,8 @@ class HValue: public ZoneObject {
     return gvn_flags_.ContainsAnyOf(AllSideEffectsFlagSet());
   }
   bool HasObservableSideEffects() const {
-    return gvn_flags_.ContainsAnyOf(AllObservableSideEffectsFlagSet());
+    return !CheckFlag(kHasNoObservableSideEffects) &&
+        gvn_flags_.ContainsAnyOf(AllObservableSideEffectsFlagSet());
   }
 
   GVNFlagSet DependsOnFlags() const {