* pointer-set.c: New file, special-purpose hash table.
	* pointer-set.h: New file.
	* tree.h (struct pointer_set_t): Declare as opaque type.
	(tree_walk): Last argument is pointer_set_t* now.
	* tree-inline.c (WALK_SUBTREE): Convert from htab to pset.
	(walk_type_fields):
	(walk_tree): Convert from htab_t to pointer_set_t for keeping
	track of which nodes have already been visited.
	(walk_tree_without_duplicates): Convert from htab_t to pointer_set_t.
	* cgraphunit.c (cgraph_create_edges): Likewise.
	(cgraph_characterize_statics_local): Likewise.
	* tree-dfa.c (collect_dfa_stats): Likewise.
	* langhooks-def.h (lhd_tree_inlining_walk_subtrees): Last arg is
	pointer_set_t* now.
	* langhooks.c (lhd_tree_inlining_walk_subtrees): Likewise.
	* langhooks.h (struct lang_hooks_for_tree_inlining): Last arg type
	of walk_subtrees is pointer_set_t* now.
	* Makefile.in (OBJS-common): add pointer-set.o
	(tree-inline.o): Depends on pointer-set.h
	(tree-dfa.o): Likewise
	(cgraphunit.o): Likewise
	* cp/Make-lang.in (pt.o): depends on pointer-set.h
	* cp/cp-tree.h (cp_walk_subtrees): Last argument is pointer_set_t* now.
	* cp/pt.c (struct pair_fn_data): Use pointer_set_t, not htab_t
	(for_each_template_parm): Convert from htab_t to pointer_set_t.
	* cp/tree.c (cp_walk_subtrees): Last argument is pointer_set_t* now.
	* java/lang.c (java_tree_inlining_walk_subtrees): Last arg is struct
	pointer_set_t* now.

From-SVN: r89062