Fix bug in graph copy while inlining loops.

src/compiler/js-inlining.cc

Index: src/compiler/js-inlining.cc
diff --git a/src/compiler/js-inlining.cc b/src/compiler/js-inlining.cc
index e3c4427e05c54d498b70593f30b464af0409d591..f2abb6c8f46122f0e59283967939e501d5a3816e 100644
--- a/src/compiler/js-inlining.cc
+++ b/src/compiler/js-inlining.cc
@@ -209,11 +209,10 @@ class CopyVisitor : public NullNodeVisitor {
   }
 
   Node* GetSentinel(Node* original) {
-    Node* sentinel = sentinels_[original->id()];
-    if (sentinel == NULL) {
-      sentinel = target_graph_->NewNode(&sentinel_op_);
+    if (sentinels_[original->id()] == NULL) {
+      sentinels_[original->id()] = target_graph_->NewNode(&sentinel_op_);
     }
-    return sentinel;
+    return sentinels_[original->id()];
   }
 
   NodeVector copies_;