2017-08-21  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/81900
	* tree-ssa-pre.c (compute_antic_aux): Properly compute changed
	for blocks with abnormal predecessors.
	(compute_antic): Do not set visited flag prematurely.

	* gcc.dg/torture/pr81900.c: New testcase.

From-SVN: r251226