tree-vrp.c (evrp_dom_walker::before_dom_children): Handle not visited but non-executable predecessors.

2016-10-18  Richard Biener  <rguenther@suse.de>

	* tree-vrp.c (evrp_dom_walker::before_dom_children): Handle
	not visited but non-executable predecessors.  Return taken edge.
	Simplify conditions and refactor propagation vs. folding step.

	* gcc.dg/tree-ssa/pr20318.c: Disable EVRP.
	* gcc.dg/tree-ssa/pr21001.c: Likewise.
	* gcc.dg/tree-ssa/pr21090.c: Likewise.
	* gcc.dg/tree-ssa/pr21294.c: Likewise.
	* gcc.dg/tree-ssa/pr21563.c: Likewise.
	* gcc.dg/tree-ssa/pr23744.c: Likewise.
	* gcc.dg/tree-ssa/pr25382.c: Likewise.
	* gcc.dg/tree-ssa/pr68431.c: Likewise.
	* gcc.dg/tree-ssa/vrp03.c: Likewise.
	* gcc.dg/tree-ssa/vrp06.c: Likewise.
	* gcc.dg/tree-ssa/vrp07.c: Likewise.
	* gcc.dg/tree-ssa/vrp09.c: Likewise.
	* gcc.dg/tree-ssa/vrp19.c: Likewise.
	* gcc.dg/tree-ssa/vrp20.c: Likewise.
	* gcc.dg/tree-ssa/vrp92.c: Likewise.
	* gcc.dg/pr68217.c: Likewise.
	* gcc.dg/predict-9.c: Likewise.
	* gcc.dg/tree-prof/val-prof-5.c: Adjust.
	* gcc.dg/predict-1.c: Likewise.

From-SVN: r241300