re PR tree-optimization/41186 (VN doesn't look through non-aliasing by offset memcpy)

re PR tree-optimization/41186 (VN doesn't look through non-aliasing by offset memcpy)

2009-08-30  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/41186
	* tree-ssa-alias.c (ptr_deref_may_alias_ref_p): Remove.
	(ao_ref_init_from_ptr_and_size): New function.
	(ref_maybe_used_by_call_p_1): Be more precise tracking
	used ranges for builtin functions.
	(ref_maybe_used_by_call_p): Adjust.
	(call_may_clobber_ref_p_1): Be more precise tracking clobbered
	ranges for builtin functions.
	* tree-ssa-alias.h (ao_ref_init_from_ptr_and_size): Declare.

	* g++.dg/torture/pr41186.C: New testcase.
	* g++.dg/tree-ssa/pr41186.C: Likewise.

From-SVN: r151226