re PR middle-end/37774 (Alignment information is lost for ARRAY_REFs)

	PR middle-end/37774
	* tree.h (get_object_alignment): Declare.
	* emit-rtl.c (set_mem_attributes_minus_bitpos): Call
	get_object_alignment if needed.
	* builtins.c (get_pointer_alignment): Move ADDR_EXPR operand handling
	to ...
	(get_object_alignment): ... here.  New function.  Try harder to
	determine alignment from get_inner_reference returned offset.

From-SVN: r141003