tree-ssa-structalias.c: alloc_pool for struct equiv_class_label

[Dimitrios Apostolou]

2011-08-22  Dimitrios Apostolou  <ji...@gmx.net>

        * tree-ssa-structalias.c (equiv_class_add)
        (perform_var_substitution, free_var_substitution_info): Created a
        new equiv_class_pool allocator pool for struct
        equiv_class_label. Changed the pointer_equiv_class_table and
        location_equiv_class_table hash tables to not iterate freeing all
        elements in the end, but just free the pool.