fix pr62009 use after free in redirect_edge_var_map_dup

The change to get the entry for the old edge before inserting the new
one was incorrect because if inserting the new one resized the table
then the pointer to the entry for the old one would become invalid.

gcc/

	* tree-ssa.c (redirect_edge_var_map_dup): insert newe before
	getting olde.

From-SVN: r213644

gcc/ChangeLog

+2014-08-05  Trevor Saunders  <tsaunders@mozilla.com>
+
+	* tree-ssa.c (redirect_edge_var_map_dup): insert newe before
+	getting olde.
+
 2014-08-05  Richard Biener  <rguenther@suse.de>
 
 	PR rtl-optimization/61672

gcc/tree-ssa.c

@@ -106,11 +106,12 @@ redirect_edge_var_map_dup (edge newe, edge olde)
   if (!edge_var_maps)
     return;
 
-  auto_vec<edge_var_map> *head = edge_var_maps->get (olde);
-  if (!head)
+  auto_vec<edge_var_map> *new_head = &edge_var_maps->get_or_insert (newe);
+  auto_vec<edge_var_map> *old_head = edge_var_maps->get (olde);
+  if (!old_head)
     return;
 
-  edge_var_maps->get_or_insert (newe).safe_splice (*head);
+  new_head->safe_splice (*old_head);
 }