re PR tree-optimization/64193 (Decreased performance after r173250)

re PR tree-optimization/64193 (Decreased performance after r173250)

2014-12-09  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/64193
	* tree-ssa-alias.c (walk_non_aliased_vuses): Add valueize parameter
	and valueize the VUSE before looking up the def stmt.
	* tree-ssa-alias.h (walk_non_aliased_vuses): Adjust prototype.
	* tree-ssa-sccvn.c (vn_reference_lookup_pieces): Pass vn_valueize
	to walk_non_aliased_vuses.
	(vn_reference_lookup): Likewise.
	* tree-ssa-dom.c (lookup_avail_expr): Pass NULL as valueize
	callback to walk_non_aliased_vuses.

	* gcc.dg/tree-ssa/ssa-fre-43.c: New testcase.

From-SVN: r218515