Preserve the original program while using graphite.

Preserve the original program while using graphite.

Earlier, graphite used to translate portions of the original program after
scop-detection in order to represent the SCoP into polyhedral model.  This was
required because each basic block was represented as independent basic block in
the polyhedral model. So all the cross-basic-block dependencies were translated
out-of-ssa.

With this patch those dependencies are also exposed to the ISL, so there is no
need to modify the original structure of the program.

After this patch we should be able to enable graphite at some default
optimization level.

Highlights:
Remove cross bb scalar to array translation
For reductions, add support for more than just INT_CST
Early bailout on codegen.
Verify loop-closed ssa structure during copy of renames
The uses of exprs should come from bb which dominates the bb
Collect the init value of close phi in loop-guard
Do not follow vuses for close-phi, postpone loop-close phi until the
    corresponding loop-phi is processed
Bail out if no bb found to place cond/loop -phis
Move insertion of liveouts at the end of codegen
Insert loop-phis in the loop-header.

This patch passes regtest and bootstrap with BOOT_CFLAGS='-O2 -fgraphite-identity -floop-nest-optimize'

2015-11-11  Aditya Kumar  <aditya.k7@samsung.com>
      Sebastian Pop  <s.pop@samsung.com>

	* graphite-isl-ast-to-gimple.c (class translate_isl_ast_to_gimple):
	  New member codegen_error
	(translate_isl_ast_for_loop): Remove call to single_succ_edge and early return.
	(translate_isl_ast_node_user): Early return in case of error.
	(translate_isl_ast_to_gimple::translate_isl_ast): Same.
	(translate_isl_ast_to_gimple::translate_pending_phi_nodes): New.
	(add_parameters_to_ivs_params): Remove macro.
	(graphite_regenerate_ast_isl): Add if_region pointer to region.
	* graphite-poly.c (new_poly_dr): Remove macro.
	(print_pdr): Same.
	(new_gimple_poly_bb): Same.
	(free_gimple_poly_bb): Same.
	(print_scop_params): Same.
	* graphite-poly.h (struct poly_dr): Same.
	(struct poly_bb): Add new_bb.
	(gbb_from_bb): Remove dead code.
	(pbb_from_bb): Same.
	* graphite-scop-detection.c (parameter_index_in_region_1): Same.
	(parameter_index_in_region): Same.
	(find_scop_parameters): Same.
	(build_cross_bb_scalars_def): New.
	(build_cross_bb_scalars_use): New.
	(graphite_find_cross_bb_scalar_vars): New
	(try_generate_gimple_bb): Reads and Writes.
	(build_alias_set): Move.
	(gather_bbs::before_dom_children): Gather bbs visited.
	(build_scops): call build_alias_set.
	* graphite-sese-to-poly.c (phi_arg_in_outermost_loop): Delete.
	(remove_simple_copy_phi): Delete.
	(remove_invariant_phi): Delete.
	(simple_copy_phi_p): Delete.
	(reduction_phi_p): Delete.
	(isl_id_for_dr): Remove unused param.
	(parameter_index_in_region_1): Remove macro usage.
	(set_scop_parameter_dim): Same.
	(add_param_constraints): Same.
	(add_conditions_to_constraints): Same
	(build_scop_iteration_domain): Same.
	(pdr_add_alias_set): Comment.
	(add_scalar_version_numbers): New.
	(build_poly_dr): ISL id.
	(build_scop_drs): Move.
	(build_poly_sr_1): Same.
	(insert_stmts): Remove.
	(build_poly_sr): New.
	(new_pbb_from_pbb): Delete.
	(insert_out_of_ssa_copy_on_edge): Delete.
	(create_zero_dim_array): Delete.
	(scalar_close_phi_node_p): Delete.
	(propagate_expr_outside_region): Delete.
	(rewrite_close_phi_out_of_ssa): Delete.
	(rewrite_phi_out_of_ssa): Delete.
	(rewrite_degenerate_phi): Delete.
	(rewrite_reductions_out_of_ssa): Delete.
	(rewrite_cross_bb_scalar_dependence): Delete.
	(handle_scalar_deps_crossing_scop_limits):
	(rewrite_cross_bb_scalar_deps): Delete.
	(build_poly_scop): Remove calls to out-of-ssa functions.
	* graphite.c (graphite_transform_loops): Early return in case of codegen error.
	* sese.c (debug_rename_map_1): Delete.
	(debug_rename_map): Delete.
	(sese_record_loop): Remove macro.
	(build_sese_loop_nests): Same.
	(new_sese_info): Same.
	(free_sese_info): Same.
	(sese_insert_phis_for_liveouts):
	(is_loop_closed_ssa_use): New.
	(number_of_phi_nodes): New.
	(bb_contains_loop_close_phi_nodes): New.
	(bb_contains_loop_phi_nodes): New.
	(phi_uses_name): New.
	(is_valid_rename):
	(get_rename): Add old_bb and loop_phi for more precise matching of
	exprs.
	(set_rename): Pass region.
	(later_of_the_two): New.
	(gsi_insert_earliest): New.
	(collect_all_ssa_names): New.
	(substitute_ssa_name): New.
	(rename_all_uses): New.
	(get_rename_from_scev): New.
	(rename_uses): Pass old_bb for more precise matching of exprs.
	(get_def_bb_for_const): New.
	(get_new_name): New.
	(get_loc): New.
	(get_edges): New.
	(copy_loop_phi_args): New.
	(copy_loop_phi_nodes): New.
	(get_loop_init_value): New.
	(find_init_value): New.
	(find_init_value_close_phi): New.
	(copy_loop_close_phi_args): New.
	(copy_loop_close_phi_nodes): New.
	(add_phi_arg_for_new_expr): New.
	(copy_cond_phi_args): New.
	(copy_cond_phi_nodes): New.
	(copy_phi_nodes): New.
	(should_copy_to_new_region): New.
	(set_rename_for_each_def): New.
	(graphite_copy_stmts_from_block): Early return in case of error.
	(copy_bb_and_scalar_dependences): Same.
	* sese.h (vec_find): New.
	(SESE_PARAMS): Delete.
	(SESE_LOOPS): Delete.
	(SESE_LOOP_NEST): Delete.
	(sese_contains_loop): Remove macro usage.
	(sese_nb_params): Same.
	(struct gimple_poly_bb): Added read_scalar_refs, write_scalar_refs.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@230200 138bc75d-0d04-0410-961f-82ee72b054a4