Fix Environment size mismatch in r6849.

src/hydrogen.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 7626 matching lines @@
 HValue* HGraphBuilder::TruncateToNumber(HValue* value, Handle<Type>* expected) {
   if (value->IsConstant()) {
     HConstant* constant = HConstant::cast(value);
     Maybe<HConstant*> number = constant->CopyToTruncatedNumber(zone());
     if (number.has_value) {
       *expected = handle(Type::Number(), isolate());
       return AddInstruction(number.value);
     }
   }
 
+  // We put temporary values on the stack, which don't correspond to anything
+  // in baseline code. Since nothing is observable we avoid recording those
+  // pushes with a NoObservableSideEffectsScope.
+  NoObservableSideEffectsScope no_effects(this);
+
   Handle<Type> expected_type = *expected;
 
   // Separate the number type from the rest.
   Handle<Type> expected_obj = handle(Type::Intersect(
       expected_type, handle(Type::NonNumber(), isolate())), isolate());
   Handle<Type> expected_number = handle(Type::Intersect(
       expected_type, handle(Type::Number(), isolate())), isolate());
 
   // We expect to get a number.
   // (We need to check first, since Type::None->Is(Type::Any()) == true.
@@ skipping 2081 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal