diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d35f141f7e07..00272783344b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Mon Apr  6 17:23:41 1998  Jim Wilson  <wilson@cygnus.com>
+
+	* haifa-sched.c (build_control_flow): Set unreachable for block whose
+	only predecessor is itself.
+
 Mon Apr  6 16:08:04 1998  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
         * c-parse.in: Include system.h, and remove stuff now made redundant.
diff --git a/gcc/haifa-sched.c b/gcc/haifa-sched.c
index 43e5264d0848..9b7c0d4744d0 100644
--- a/gcc/haifa-sched.c
+++ b/gcc/haifa-sched.c
@@ -1220,7 +1220,10 @@ build_control_flow ()
   for (i = 0; i < n_basic_blocks; i++)
     {
       nr_edges += num_succs[i];
-      if (num_preds[i] == 0)
+      /* ??? We must also detect unreachable loops here.  We only handle the
+	 trivial case of a loop with one basic block for now.  */
+      if (num_preds[i] == 0
+	  || (num_preds[i] == 1 && INT_LIST_VAL (s_preds[i]) == i))
 	unreachable = 1;
     }