[PATCH] Fix PR92669

[Richard Biener]

Committed as obvious.

Richard.

2019-11-26  Richard Biener  <rguent...@suse.de>

        PR middle-end/92669
        * cfganal.c (pre_and_rev_post_order_compute_fn): Deal with
        NULL pre_order.

Index: gcc/cfganal.c
===================================================================
--- gcc/cfganal.c       (revision 278681)
+++ gcc/cfganal.c       (working copy)
@@ -1030,6 +1030,8 @@ pre_and_rev_post_order_compute_fn (struc
     }
 
   /* Clear the temporarily allocated flag.  */
+  if (!rev_post_order)
+    rev_post_order = pre_order;
   for (int i = 0; i < pre_order_num; ++i)
     BASIC_BLOCK_FOR_FN (fn, rev_post_order[i])->flags &= ~visited;