* ipa-prop.h (ipa_ancestor_jf_data): Update ocmment.
	* ipa-prop.c (ipa_set_jf_known_type): Return early when
	not devirtualizing.
	(ipa_set_ancestor_jf): Set type to NULL hwen it is not preserved;
	do more sanity checks.
	(detect_type_change): Return true when giving up early.
	(compute_complex_assign_jump_func): Fix type parameter of
	ipa_set_ancestor_jf.
	(compute_complex_ancestor_jump_func): Likewise.
	(update_jump_functions_after_inlining): Fix updating of
	ancestor function.
	* ipa-cp.c (ipa_get_jf_ancestor_result): Be ready for type
	to be NULL.

From-SVN: r207877