PR tree-optimization/20920
	* tree-pretty-print.c (dump_generic_node): Show '(ab)' if an
	SSA_NAME flows through an abnormal edge.
	* tree-vrp.c (infer_value_range): Ignore SSA names that flow
	through abnormal edges.
	(maybe_add_assert_expr): Likewise.

	PR tree-optimization/20920
	* g++.dg/tree-ssa/pr20920.C: New test.

From-SVN: r97971