2019-09-25  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/91896
	* tree-vect-loop.c (vectorizable_reduction): The single
	def-use cycle optimization cannot apply when there's more
	than one pattern stmt involved.

	* gcc.dg/torture/pr91896.c: New testcase.

From-SVN: r276158