re PR tree-optimization/41490 (tree-ssa-sink does not really work)

re PR tree-optimization/41490 (tree-ssa-sink does not really work)

2011-03-15  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/41490
	* tree-ssa-dce.c (propagate_necessity): Handle returns without
	value but with VUSE.
	* tree-ssa-operands.c (parse_ssa_operands): Add a VUSE on all
	return statements.
	* tree-ssa-sink.c (statement_sink_location): Fix store sinking.
	* tree-ssa-phiopt.c (tree_ssa_phiopt_worker): Handle virtual PHIs.
	* tree-tailcall.c (find_tail_calls): Ignore returns.

	* gcc.dg/tree-ssa/ssa-sink-6.c: New testcase.
	* gcc.dg/tree-ssa/ssa-sink-7.c: Likewise.
	* gcc.dg/tree-ssa/ssa-sink-8.c: Likewise.
	* gcc.dg/tree-ssa/ssa-sink-9.c: Likewise.
	* g++.dg/tree-ssa/pr33604.C: Adjust.

From-SVN: r170984