2009-05-25  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/36327
	* tree-ssa-alias.c (walk_non_aliased_vuses): Add second walker
	callback for reference translation or lookup at the point
	of may-defs.
	* tree-ssa-alias.h (walk_non_aliased_vuses): Adjust prototype.
	* tree-ssa-sccvn.c (get_ref_from_reference_ops): Bail out
	for union COMPONENT_REFs.
	(vn_reference_lookup_3): New callback.  Lookup from memset
	and CONSTRUCTOR assignment, translate through struct copies.
	(vn_reference_lookup_pieces): Make sure to not free the
	passed operands array.  Adjust walk_non_aliased_vuses call.
	(vn_reference_lookup): Adjust walk_non_aliased_vuses call,
	make sure we do not leak memory.

	* gcc.dg/tree-ssa/ssa-fre-24.c: New testcase.
	* gcc.dg/tree-ssa/ssa-fre-25.c: Likewise.
	* gcc.dg/tree-ssa/sra-2.c: Disable FRE.
	* gcc.dg/vect/no-vfa-vect-43.c: Adjust.
	* gcc.dg/vect/vect-40.c: Likewise.
	* gcc.dg/vect/vect-42.c: Likewise.
	* gcc.dg/vect/vect-46.c: Likewise.
	* gcc.dg/vect/vect-76.c: Likewise.

From-SVN: r147851