diff --git a/gcc/combine.cc b/gcc/combine.cc
index 6344cd3c9f2..e533631d0e6 100644
--- a/gcc/combine.cc
+++ b/gcc/combine.cc
@@ -3184,11 +3184,21 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
 	  && (cc_use_loc = find_single_use (SET_DEST (newpat), i3,
 					    &cc_use_insn)))
 	{
-	  compare_code = orig_compare_code = GET_CODE (*cc_use_loc);
-	  if (is_a <scalar_int_mode> (GET_MODE (i2dest), &mode))
-	    compare_code = simplify_compare_const (compare_code, mode,
-						   &op0, &op1);
-	  target_canonicalize_comparison (&compare_code, &op0, &op1, 1);
+	  if (COMPARISON_P (*cc_use_loc))
+	    {
+	      compare_code = orig_compare_code = GET_CODE (*cc_use_loc);
+	      if (is_a <scalar_int_mode> (GET_MODE (i2dest), &mode))
+		compare_code = simplify_compare_const (compare_code, mode,
+						       &op0, &op1);
+	      target_canonicalize_comparison (&compare_code, &op0, &op1, 1);
+	    }
+	  else
+	    {
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		fprintf (dump_file, "CC register not used in comparison.\n");
+	      undo_all ();
+	      return 0;
+	    }
 	}
 
       /* Do the rest only if op1 is const0_rtx, which may be the