2008-03-15  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-ccp.c (get_symbol_constant_value): Export.
	(fold_const_aggregate_ref): Likewise.
	(get_value): Return NULL if we don't have any values.
	(ccp_finalize): Set const_val to NULL after freeing it.
	* tree-flow.h (get_symbol_constant_value): Declare.
	(fold_const_aggregate_ref): Likewise.
	* tree-ssa-sccvn.c (try_to_simplify): Use them.

	* gcc.dg/pr23911.c: Adjust testcase.
	* gcc.dg/tree-ssa/pr14841.c: Likewise.
	* gcc.dg/tree-ssa/20030922-2.c: Likewise.

From-SVN: r133251