tree-ssa-sccvn.c: use auto_vec for sccvn_dom_walker::cond_stack

gcc/ChangeLog:

2016-07-12  Trevor Saunders  <tbsaunde+gcc@tbsaunde.org>

	* tree-ssa-sccvn.c (sccvn_dom_walker::~sccvn_dom_walker): remove.
	(sccvn_dom_walker): make cond_stack an auto_vec.

From-SVN: r238284

gcc/ChangeLog

 2016-07-12  Trevor Saunders  <tbsaunde+gcc@tbsaunde.org>
 
+	* tree-ssa-sccvn.c (sccvn_dom_walker::~sccvn_dom_walker): remove.
+	(sccvn_dom_walker): make cond_stack an auto_vec.
+
+2016-07-12  Trevor Saunders  <tbsaunde+gcc@tbsaunde.org>
+
 	* ree.c (struct ext_state): Make type of members auto_vec.
 	(find_and_remove_re): Adjust.
 

gcc/tree-ssa-sccvn.c

@@ -4455,8 +4455,7 @@ class sccvn_dom_walker : public dom_walker
 {
 public:
   sccvn_dom_walker ()
-    : dom_walker (CDI_DOMINATORS, true), fail (false), cond_stack (vNULL) {}
-  ~sccvn_dom_walker ();
+    : dom_walker (CDI_DOMINATORS, true), fail (false), cond_stack (0) {}
 
   virtual edge before_dom_children (basic_block);
   virtual void after_dom_children (basic_block);
@@ -4467,15 +4466,10 @@ public:
 		     enum tree_code code, tree lhs, tree rhs, bool value);
 
   bool fail;
-  vec<std::pair <basic_block, std::pair <vn_nary_op_t, vn_nary_op_t> > >
+  auto_vec<std::pair <basic_block, std::pair <vn_nary_op_t, vn_nary_op_t> > >
     cond_stack;
 };
 
-sccvn_dom_walker::~sccvn_dom_walker ()
-{
-  cond_stack.release ();
-}
-
 /* Record a temporary condition for the BB and its dominated blocks.  */
 
 void