Use const-ref instead of values for sese_l passed to functions.

Use const-ref instead of values for sese_l passed to functions.

gcc/ChangeLog:

2015-12-24  hiraditya  <hiraditya@msn.com>

        * graphite-sese-to-poly.c (build_loop_iteration_domains): Use ref instead of value.
        * sese.c (invariant_in_sese_p_rec): Use const ref instead of value.
        (scalar_evolution_in_region): Same
        * sese.h (bb_in_region): Same
        (bb_in_sese_p): Same.
        (stmt_in_sese_p): Same.
        (defined_in_sese_p): Same.
        (loop_in_sese_p): Same.

From-SVN: r231947