re PR tree-optimization/78343 (Loop is not eliminated)

re PR tree-optimization/78343 (Loop is not eliminated)

2016-11-24  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/78343
	* passes.def: Add CD-DCE pass after loop splitting.
	* tree-ssa-dce.c (find_obviously_necessary_stmts): Move
	SCEV init/finalize ...
	(perform_tree_ssa_dce): ... here.  Deal with being
	executed inside the loop pipeline in aggressive mode.

	* gcc.dg/tree-ssa/sccp-2.c: New testcase.
	* gcc.dg/autopar/uns-outer-6.c: Adjust.
	* gcc.dg/tree-ssa/20030808-1.c: Likewise.
	* gcc.dg/tree-ssa/20040305-1.c: Likewise.
	* gcc.dg/vect/pr38529.c: Likewise.

From-SVN: r242872