re PR lto/47497 (SPEC CPU 2006 failed to link with LTO -fuse-linker-plugin -fwhole...

re PR lto/47497 (SPEC CPU 2006 failed to link with LTO -fuse-linker-plugin -fwhole-program)

	PR lto/47497
	* lto-symtab.c (lto_cgraph_replace_node): Do not set thunk.alias.
	(lto_symtab_merge_cgraph_nodes_1): Update thunk.alias pointers here.
	* cgraph.h (cgraph_same_body_alias, cgraph_add_thunk): Add node pointers.
	* cgraph.c (cgraph_same_body_alias_1, cgraph_same_body_alias,
	cgraph_add_thunk): Add node pointers.
	* lto-cgraph.c (lto_output_node): Verify that thunks&aliases are
	associated to right node.
	(input_node): Update use of cgraph_same_body_alias
	and cgraph_add_thunk.

	* optimize.c (maybe_clone_body): Update call of cgraph_same_body_alias
	and cgraph_add_thunk.
	* method.c (make_alias_for_thunk, use_thunk): Likewise.
	* mangle.c (mangle_decl): Likewise.

From-SVN: r170682