cgraphbuild.c (build_cgraph_edges): Do not walk into debugs.

	* cgraphbuild.c (build_cgraph_edges): Do not walk into debugs.
	(make_pass_rebuild_cgraph_edges): Also clear references.
	* cgraph.c (verify_cgraph_node): Add basic ipa-ref verifier.
	* ipa-inline-transform.c (inline_transform): Remove all references
	after inlining.
	* cgraphunit.c (expand_function): Remove all references after expansion.
	* ipa-ref.c (ipa_ref_has_aliases_p): Fix formatting.
	(ipa_find_reference): Rewrite to iterator.
	(remove_stmt_references): Likewise.
	(ipa_clear_stmts_in_references): New function.
	* ipa-ref.h (ipa_clear_stmts_in_references): Declare.
	* cgraphclones.c (cgraph_materialize_all_clones): Remove or clear references.
	* ipa-split.c (split_function): Remove references in split function.

From-SVN: r201601