2018-09-17  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/87328
	* tree-ssa-sccvn.c (process_bb): Remove assertion about not
	visiting unexecutable backedges when not iterating.
	(do_rpo_vn): Mark all edges not executable even when not
	iterating.

	* gcc.dg/torture/pr87328.c: New testcase.

From-SVN: r264369