diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 78bd1f88c63..fefac6e0c95 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2017-10-13  Jan Hubicka  <hubicka@ucw.cz>
+
+	* cfghooks.c (verify_flow_info): Check that edge probabilities are
+	set.
+
 2017-10-13  Nathan Sidwell  <nathan@acm.org>
 
 	* tree-core.h (tree_contains_struct): Make bool.
diff --git a/gcc/cfghooks.c b/gcc/cfghooks.c
index 18dc49a035e..c15c58c728e 100644
--- a/gcc/cfghooks.c
+++ b/gcc/cfghooks.c
@@ -152,6 +152,7 @@ verify_flow_info (void)
 		 bb->index, bb->frequency);
 	  err = 1;
 	}
+
       FOR_EACH_EDGE (e, ei, bb->succs)
 	{
 	  if (last_visited [e->dest->index] == bb)
@@ -160,6 +161,13 @@ verify_flow_info (void)
 		     e->src->index, e->dest->index);
 	      err = 1;
 	    }
+	  if (profile_status_for_fn (cfun) >= PROFILE_GUESSED
+	      && !e->probability.initialized_p ())
+	    {
+	      error ("Uninitialized probability of edge %i->%i", e->src->index,
+		     e->dest->index);
+	      err = 1;
+	    }
 	  if (!e->probability.verify ())
 	    {
 	      error ("verify_flow_info: Wrong probability of edge %i->%i",