2018-03-19  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/84859
	* tree-ssa-phiopt.c (single_trailing_store_in_bb): New function.
	(cond_if_else_store_replacement): Perform sinking operation on
	single-store BBs regardless of MAX_STORES_TO_SINK setting.
	Generalize what a BB with a single eligible store is.

	* gcc.dg/tree-ssa/pr84859.c: New testcase.
	* gcc.dg/tree-ssa/pr35286.c: Disable cselim.
	* gcc.dg/tree-ssa/split-path-6.c: Likewise.
	* gcc.dg/tree-ssa/split-path-7.c: Likewise.

From-SVN: r258645