2018-09-04  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/87211
	* tree-ssa-sccvn.c (visit_phi): When value-numbering to a
	backedge value we're supposed to treat as VARYING also number
	the PHI to VARYING in case it got a different value-number already.

	* gcc.dg/torture/pr87211.c: New testcase.

From-SVN: r264079