[PR 91468] Small fixes in ipa-cp.c and ipa-prop.c

[PR 91468] Small fixes in ipa-cp.c and ipa-prop.c

2019-08-28  Martin Jambor  <mjambor@suse.cz>

	PR ipa/91468
	* ipa-cp.c (merge_agg_lats_step): Removed redundant test, made a
	checking assert a normal assert to test it really is redundant.
	* ipa-prop.c (compute_complex_assign_jump_func): Removed
	redundant test.
	(update_jump_functions_after_inlining): Removed combining unary
	arithmetic operations with an ancestor jump function.
	(ipcp_modif_dom_walker::before_dom_children): Fix wrong use of rhs
	instead of t.

From-SVN: r274992