tree-vect-loop.c (vect_analyze_loop_operations): Analyze loop-closed PHIs that are vect_internal_def.

2019-09-26  Richard Biener  <rguenther@suse.de>

	* tree-vect-loop.c (vect_analyze_loop_operations): Analyze
	loop-closed PHIs that are vect_internal_def.
	(vect_create_epilog_for_reduction): Exit early for nested cycles.
	Simplify.
	(vectorizable_lc_phi): New.
	* tree-vect-stmts.c (vect_analyze_stmt): Call vectorize_lc_phi.
	(vect_transform_stmt): Likewise.
	* tree-vectorizer.h (stmt_vec_info_type): Add lc_phi_info_type.
	(vectorizable_lc_phi): Declare.

From-SVN: r276157