* common.opt (flto-odr-type-merging): New flag.
	* ipa-deivrt.c (hash_type_name): Use ODR names for hasing if availale.
	(types_same_for_odr): Likewise.
	(odr_subtypes_equivalent_p): Likewise.
	(add_type_duplicate): Do not walk type variants.
	(register_odr_type): New function.
	* ipa-utils.h (register_odr_type): Declare.
	(odr_type_p): New function.
	* langhooks.c (lhd_set_decl_assembler_name): Do not compute
	TYPE_DECLs
	* doc/invoke.texi (-flto-odr-type-merging): Document.
	* tree.c (need_assembler_name_p): Compute ODR names when asked
	for it.
	* tree.h (DECL_ASSEMBLER_NAME): Update comment.

	* lto.c (lto_read_decls): Register ODR types.

From-SVN: r215196