Prevent overzealous bailout due to script context.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/hydrogen.h"
 
 #include <sstream>
 
 #include "src/v8.h"
 
@@ skipping 4202 matching lines @@
   }
 }
 
 
 bool HOptimizedGraphBuilder::BuildGraph() {
   if (IsSubclassConstructor(current_info()->function()->kind())) {
     Bailout(kSuperReference);
     return false;
   }
 
-  if (current_info()->scope()->is_script_scope()) {
+  int slots = current_info()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
+  if (current_info()->scope()->is_script_scope() && slots > 0) {
     Bailout(kScriptContext);
     return false;
   }
 
   Scope* scope = current_info()->scope();
   SetUpScope(scope);
 
   // Add an edge to the body entry.  This is warty: the graph's start
   // environment will be used by the Lithium translation as the initial
   // environment on graph entry, but it has now been mutated by the
@@ skipping 8685 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal