diff --git a/gcc/postreload.c b/gcc/postreload.c
index f6258285022..c9e637500f1 100644
--- a/gcc/postreload.c
+++ b/gcc/postreload.c
@@ -592,6 +592,13 @@ reload_cse_simplify_operands (rtx_insn *insn, rtx testreg)
 	}
     }
 
+  /* The loop below sets alternative_order[0] but -Wmaybe-uninitialized
+     can't know that.  Clear it here to avoid the warning.  */
+  alternative_order[0] = 0;
+  gcc_assert (!recog_data.n_alternatives
+	      || (which_alternative >= 0
+		  && which_alternative < recog_data.n_alternatives));
+
   /* Record all alternatives which are better or equal to the currently
      matching one in the alternative_order array.  */
   for (i = j = 0; i < recog_data.n_alternatives; i++)