tree-ssa-pre.c (compute_antic): Re-use inverted postorder for partial antic compute.

2018-08-27  Richard Biener  <rguenther@suse.de>

	* tree-ssa-pre.c (compute_antic): Re-use inverted postorder
	for partial antic compute.

From-SVN: r263874

gcc/ChangeLog

+2018-08-27  Richard Biener  <rguenther@suse.de>
+
+	* tree-ssa-pre.c (compute_antic): Re-use inverted postorder
+	for partial antic compute.
+
 2018-08-27  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/87065

gcc/tree-ssa-pre.c

@@ -2414,9 +2414,7 @@ compute_antic (void)
     {
       /* For partial antic we ignore backedges and thus we do not need
          to perform any iteration when we process blocks in postorder.  */
-      int postorder_num
-	= pre_and_rev_post_order_compute (NULL, postorder.address (), false);
-      for (i = postorder_num - 1 ; i >= 0; i--)
+      for (i = postorder.length () - 1; i >= 0; i--)
 	{
 	  basic_block block = BASIC_BLOCK_FOR_FN (cfun, postorder[i]);
 	  compute_partial_antic_aux (block,