remove unused struct base_alias_pair

remove unused struct base_alias_pair

2015-10-06  Aditya Kumar  <aditya.k7@samsung.com>
                Sebastian Pop  <s.pop@samsung.com>

                * graphite-poly.c (free_data_refs_aux): Remove.
                (free_gimple_poly_bb): Do not call free_data_refs_aux.
                * graphite-poly.h (struct base_alias_pair): Remove.
                * graphite-sese-to-poly.c (pdr_add_alias_set): Remove all uses of
                base_alias_pair and dr->aux.
                (build_alias_set): Same.
                * tree-data-ref.c (create_data_ref): Initialize alias_set.
                * tree-data-ref.h (data_reference): Add alias_set.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@228544 138bc75d-0d04-0410-961f-82ee72b054a4