diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fdae41bc012..0676b06d19a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Sat Oct 16 02:48:22 1999  Jeffrey A Law  (law@cygnus.com)
+
+	* haifa-sched.c (compute_block_forward_dependencies): Only check
+	for notes, deleted insns and duplicates if ENABLE_CHECKING is defined.
+
 Sat Oct 16 00:07:01 1999  Richard Henderson  <rth@cygnus.com>
 
 	* gcse.c (hash_expr_1): Add in MEM_ALIAS_SET.
diff --git a/gcc/haifa-sched.c b/gcc/haifa-sched.c
index 3d1bd297255..5e4c1ba4363 100644
--- a/gcc/haifa-sched.c
+++ b/gcc/haifa-sched.c
@@ -6093,11 +6093,18 @@ compute_block_forward_dependences (bb)
 	  if (x != XEXP (link, 0))
 	    continue;
 
-	  /* Ignore dependences upon deleted insn.  */
-	  if (GET_CODE (x) == NOTE || INSN_DELETED_P (x))
-	    continue;
-	  if (find_insn_list (insn, INSN_DEPEND (x)))
-	    continue;
+#ifdef ENABLE_CHECKING
+	  /* If add_dependence is working properly there should never
+	     be notes, deleted insns or duplicates in the backward
+	     links.  Thus we need not check for them here.
+
+	     However, if we have enabled checking we might as well go
+	     ahead and verify that add_dependence worked properly.  */
+	  if (GET_CODE (x) == NOTE
+	      || INSN_DELETED_P (x)
+	      || find_insn_list (insn, INSN_DEPEND (x)))
+	    abort ();
+#endif
 
 	  new_link = alloc_INSN_LIST (insn, INSN_DEPEND (x));