PR c++/92458
	* tree-hash-traits.h (tree_decl_hash, tree_ssa_name_hash,
	tree_hash): Move to ...
	* tree.h (tree_decl_hash, tree_ssa_name_hash, tree_hash): ... here.
	(struct decl_tree_cache_traits, struct type_tree_cache_traits): New
	types.
	(decl_tree_cache_map, tree_tree_cache_map): New typedefs.

	* init.c (nsdmi_inst): Change type to
	decl_tree_cache_map * from tree_cache_map *.
	* constraint.cc (decl_constraints): Likewise.
	* decl.c (get_tuple_decomp_init): Likewise.
	* pt.c (defarg_inst, explicit_specifier_map): Likewise.
	(tsubst_default_argument, store_explicit_specifier): Use
	decl_tree_cache_map::create_ggc rather than
	tree_cache_map::create_ggc.
	* cp-objcp-common.c (debug_type_map): Change type to
	type_tree_cache_map * from tree_cache_map *.

	* g++.dg/pch/pr92458.C: New test.
	* g++.dg/pch/pr92458.Hs: New test.

From-SVN: r278633