remove dead code of commutative_reductions

remove dead code of commutative_reductions

This code is not used anymore after we removed the previous loop optimizer (not
based on the ISL scheduler.)  We will add back the detection of commutative
reductions after we improve the code generation of scalar dependences (by not
going out of SSA for scalar dependences just to expose them to the data
dependence graph.)

Patch passed bootstrap and check on x86_64-linux with ISL-0.15.

2015-09-29  Sebastian Pop  <s.pop@samsung.com>
            Aditya Kumar  <aditya.k7@samsung.com>

            * graphite-sese-to-poly.c (gsi_for_phi_node): Remove.
            (nb_data_writes_in_bb): Remove.
            (split_pbb): Remove.
            (split_reduction_stmt): Remove.
            (is_reduction_operation_p): Remove.
            (phi_contains_arg): Remove.
            (follow_ssa_with_commutative_ops): Remove.
            (detect_commutative_reduction_arg): Remove.
            (detect_commutative_reduction_assign): Remove.
            (follow_inital_value_to_phi): Remove.
            (edge_initial_value_for_loop_phi): Remove.
            (initial_value_for_loop_phi): Remove.
            (used_outside_reduction): Remove.
            (detect_commutative_reduction): Remove.
            (translate_scalar_reduction_to_array_for_stmt): Remove.
            (remove_phi): Remove.
            (dr_indices_valid_in_loop): Remove.
            (close_phi_written_to_memory): Remove.
            (translate_scalar_reduction_to_array): Remove.
            (rewrite_commutative_reductions_out_of_ssa_close_phi): Remove.
            (rewrite_commutative_reductions_out_of_ssa_loop): Remove.
            (rewrite_commutative_reductions_out_of_ssa): Remove.
            (build_poly_scop): Remove call to rewrite_commutative_reductions_out_of_ssa.

Co-Authored-By: Aditya Kumar <aditya.k7@samsung.com>
From-SVN: r228255