2010-10-14  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/44913
	* tree-data-ref.c (disjoint_objects_p): Remove.
	(dr_may_alias_p): Simplify.  Only hand the base object to
	the alias-oracle.
	* tree-ssa-alias.c (ptr_deref_may_alias_decl_p): Handle
	some more trees, bail out instead of asserting.
	(ptr_derefs_may_alias_p): Likewise.  Export.
	(refs_may_alias_p_1): Handle STRING_CSTs.
	* tree-ssa-alias.h (ptr_derefs_may_alias_p): Declare.

	* gcc.dg/torture/pr44913.c: New testcase.

From-SVN: r165473