Verifier must ensure that start and end node of graph are set.

src/compiler/verifier.cc

Index: src/compiler/verifier.cc
diff --git a/src/compiler/verifier.cc b/src/compiler/verifier.cc
index 1606b7b3bec9470ebfcc2430dfbc435883751993..1525490d1d4b7f140edc93d8b53f84f7c33c7a23 100644
--- a/src/compiler/verifier.cc
+++ b/src/compiler/verifier.cc
@@ -224,8 +224,10 @@ GenericGraphVisit::Control Verifier::Visitor::Pre(Node* node) {
 void Verifier::Run(Graph* graph) {
   Visitor visitor(graph->zone());
 
+  CHECK_NE(NULL, graph->start());
   visitor.from_start = true;
   graph->VisitNodeUsesFromStart(&visitor);
+  CHECK_NE(NULL, graph->end());
   visitor.from_start = false;
   graph->VisitNodeInputsFromEnd(&visitor);