Finish removing class move_computations_dom_walker

r232820 (aka 2c7b2f8860794cc9b9cf5eeea9d7dc109c0de3be) removed the
implementation of class move_computations_dom_walker, but kept the decl.

This patch removes the stray decl.

gcc/ChangeLog:
	PR tree-optimization/69452
	* tree-ssa-loop-im.c (class move_computations_dom_walker): Remove
	decl.

From-SVN: r256963

gcc/ChangeLog

+2018-01-22  David Malcolm  <dmalcolm@redhat.com>
+
+	PR tree-optimization/69452
+	* tree-ssa-loop-im.c (class move_computations_dom_walker): Remove
+	decl.
+
 2018-01-22  Sebastian Perta  <sebastian.perta@renesas.com>
 
 	* config/rl78/rl78-expand.md: New define_expand "bswaphi2"

gcc/tree-ssa-loop-im.c

@@ -1081,17 +1081,6 @@ invariantness_dom_walker::before_dom_children (basic_block bb)
   return NULL;
 }
 
-class move_computations_dom_walker : public dom_walker
-{
-public:
-  move_computations_dom_walker (cdi_direction direction)
-    : dom_walker (direction), todo_ (0) {}
-
-  virtual edge before_dom_children (basic_block);
-
-  unsigned int todo_;
-};
-
 /* Hoist the statements in basic block BB out of the loops prescribed by
    data stored in LIM_DATA structures associated with each statement.  Callback
    for walk_dominator_tree.  */