void switch_to_PRE_table (void);
tree vn_nary_op_lookup (tree);
void vn_nary_op_insert (tree, tree);
-tree vn_reference_lookup (tree, VEC (tree, gc) *);
+tree vn_reference_lookup (tree, VEC (tree, gc) *, bool);
void vn_reference_insert (tree, tree, VEC (tree, gc) *);
VEC (tree, gc) *shared_vuses_from_stmt (tree);
VEC (tree, gc) *copy_vuses_from_stmt (tree);