2018-11-09  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/87621
	* tree-vect-loop.c (vectorizable_reduction): Handle reduction
	op with only phi inputs.
	* tree-ssa-loop-ch.c: Include tree-ssa-sccvn.h.
	(ch_base::copy_headers): Run CSE on copied loop headers.
	(pass_ch_vect::process_loop_p): Simplify.

	* g++.dg/vect/pr87621.cc: New testcase.

From-SVN: r265959