5006671f1a
2009-04-03 Richard Guenther <rguenther@suse.de> PR middle-end/13146 PR tree-optimization/23940 PR tree-optimization/33237 PR middle-end/33974 PR middle-end/34093 PR tree-optimization/36201 PR tree-optimization/36230 PR tree-optimization/38049 PR tree-optimization/38207 PR tree-optimization/38230 PR tree-optimization/38301 PR tree-optimization/38585 PR middle-end/38895 PR tree-optimization/38985 PR tree-optimization/39299 * tree-ssa-structalias.h: Remove. * tree-ssa-operands.h (NULL_USE_OPERAND_P): Make of type use_operand_p. (NULL_DEF_OPERAND_P): Make of type def_operand_p. (struct vuse_element_d): Remove. (struct vuse_vec_d): Likewise. (VUSE_VECT_NUM_ELEM, VUSE_VECT_ELEMENT_NC, VUSE_ELEMENT_PTR_NC, VUSE_ELEMENT_VAR_NC, VUSE_VECT_ELEMENT, VUSE_ELEMENT_PTR, SET_VUSE_VECT_ELEMENT, SET_VUSE_ELEMENT_VAR, SET_VUSE_ELEMENT_PTR, VUSE_ELEMENT_VAR): Likewise. (struct voptype_d): Likewise. (NUM_VOP_FREE_BUCKETS): Likewise. (struct ssa_operands): Remove vop_free_buckets and mpt_table fields. (struct stmt_operands_d): Remove. (VUSE_OP_PTR, VUSE_OP, SET_VUSE_OP, VUSE_NUM, VUSE_VECT, VDEF_RESULT_PTR, VDEF_RESULT, VDEF_OP_PTR, VDEF_OP, SET_VDEF_OP, VDEF_NUM, VDEF_VECT): Likewise. (copy_virtual_operands): Remove. (operand_build_cmp): Likewise. (create_ssa_artificial_load_stmt): Likewise. (enum ssa_op_iter_type): Remove ssa_op_iter_vdef. (struct ssa_operand_iterator_d): Remove vuses, vdefs, mayusesm vuse_index and mayuse_index members. Pack and move done and iter_type members to the front. (SSA_OP_VMAYUSE): Remove. (SSA_OP_VIRTUAL_USES): Adjust. (FOR_EACH_SSA_VDEF_OPERAND): Remove. (unlink_stmt_vdef): Declare. (add_to_addressable_set): Remove. * tree-vrp.c (stmt_interesting_for_vrp): Adjust. (vrp_visit_stmt): Likewise. * doc/tree-ssa.texi (Alias analysis): Update. * doc/invoke.texi (max-aliased-vops): Remove docs. (avg-aliased-vops): Likewise. * tree-into-ssa.c (syms_to_rename): Remove. (need_to_update_vops_p): Likewise. (need_to_initialize_update_ssa_p): Rename to ... (update_ssa_initialized_fn): ... this. Track function we are initialized for. (symbol_marked_for_renaming): Simplify. (add_new_name_mapping): Do not set need_to_update_vops_p. (dump_currdefs): Use SYMS_TO_RENAME. (rewrite_update_stmt): Always walk all uses/defs. (dump_update_ssa): Adjust. (init_update_ssa): Take function argument. Track what we are initialized for. (delete_update_ssa): Reset SYMS_TO_RENAME and update_ssa_initialized_fn. (create_new_def_for): Initialize for cfun, assert we are initialized for cfun. (mark_sym_for_renaming): Simplify. (mark_set_for_renaming): Do not initialize update-ssa. (need_ssa_update_p): Simplify. Take function argument. (name_mappings_registered_p): Assert we ask for the correct function. (name_registered_for_update_p): Likewise. (ssa_names_to_replace): Likewise. (release_ssa_name_after_update_ssa): Likewise. (update_ssa): Likewise. Use SYMS_TO_RENAME. (dump_decl_set): Do not print a newline. (debug_decl_set): Do it here. (dump_update_ssa): And here. * tree-ssa-loop-im.c (move_computations): Adjust. (movement_possibility): Likewise. (determine_max_movement): Likewise. (gather_mem_refs_stmt): Likewise. * tree-dump.c (dequeue_and_dump): Do not handle SYMBOL_MEMORY_TAG or NAME_MEMORY_TAG. * tree-complex.c (update_all_vops): Remove. (expand_complex_move): Adjust. * tree-ssa-loop-niter.c (chain_of_csts_start): Use NULL_TREE. Simplify test for memory referencing statement. Exclude non-invariant ADDR_EXPRs. * tree-pretty-print.c (dump_generic_node): Do not handle memory tags. * tree-loop-distribution.c (generate_memset_zero): Adjust. (rdg_flag_uses): Likewise. * tree-tailcall.c (suitable_for_tail_opt_p): Remove memory-tag related code. (tree_optimize_tail_calls_1): Also split the edge from the entry block if we have degenerate PHI nodes in the first basic block. * tree.c (init_ttree): Remove memory-tag related code. (tree_code_size): Likewise. (tree_node_structure): Likewise. (build7_stat): Re-write to be build6_stat. * tree.h (MTAG_P, TREE_MEMORY_TAG_CHECK, TMR_TAG): Remove. (SSA_VAR_P): Adjust. (struct tree_memory_tag): Remove. (struct tree_memory_partition_tag): Likewise. (union tree_node): Adjust. (build7): Re-write to be build6. * tree-pass.h (pass_reset_cc_flags): Remove. (TODO_update_address_taken): New flag. (pass_simple_dse): Remove. * ipa-cp.c (ipcp_update_callgraph): Update SSA form. * params.h (MAX_ALIASED_VOPS): Remove. (AVG_ALIASED_VOPS): Likewise. * omp-low.c (expand_omp_taskreg): Update SSA form. * tree-ssa-dse.c (dse_optimize_stmt): Properly query if the rhs aliases the lhs in a copy stmt. * tree-ssa-dse.c (struct address_walk_data): Remove. (memory_ssa_name_same): Likewise. (memory_address_same): Likewise. (get_kill_of_stmt_lhs): Likewise. (dse_possible_dead_store_p): Simplify, use the oracle. Handle unused stores. Look through PHI nodes into post-dominated regions. (dse_optimize_stmt): Simplify. Properly remove stores. (tree_ssa_dse): Compute dominators. (execute_simple_dse): Remove. (pass_simple_dse): Likewise. * ipa-reference.c (scan_stmt_for_static_refs): Open-code gimple_loaded_syms and gimple_stored_syms computation. * toplev.c (dump_memory_report): Dump alias and pta stats. * tree-ssa-sccvn.c (vn_reference_compute_hash): Simplify. (vn_reference_eq): Likewise. (vuses_to_vec, copy_vuses_from_stmt, vdefs_to_vec, copy_vdefs_from_stmt, shared_lookup_vops, shared_vuses_from_stmt, valueize_vuses): Remove. (get_def_ref_stmt_vuses): Simplify. Rename to ... (get_def_ref_stmt_vuse): ... this. (vn_reference_lookup_2): New function. (vn_reference_lookup_pieces): Use walk_non_aliased_vuses for walking equivalent vuses. Simplify. (vn_reference_lookup): Likewise. (vn_reference_insert): Likewise. (vn_reference_insert_pieces): Likewise. (visit_reference_op_call): Simplify. (visit_reference_op_load): Likewise. (visit_reference_op_store): Likewise. (init_scc_vn): Remove shared_lookup_vuses initialization. (free_scc_vn): Remove shared_lookup_vuses freeing. (sort_vuses, sort_vuses_heap): Remove. (get_ref_from_reference_ops): Export. * tree-ssa-sccvn.h (struct vn_reference_s): Replace vuses vector with single vuse pointer. (vn_reference_lookup_pieces, vn_reference_lookup, vn_reference_insert, vn_reference_insert_pieces): Adjust prototypes. (shared_vuses_from_stmt): Remove. (get_ref_from_reference_ops): Declare. * tree-ssa-loop-manip.c (slpeel_can_duplicate_loop_p): Adjust. * tree-ssa-copyrename.c (copy_rename_partition_coalesce): Remove memory-tag related code. * tree-ssa-ccp.c (get_symbol_constant_value): Remove memory-tag code. (likely_value): Add comment, skip static-chain of call statements. (surely_varying_stmt_p): Adjust. (gimplify_and_update_call_from_tree): Likewise. (execute_fold_all_builtins): Do not rebuild alias info. (gimplify_and_update_call_from_tree): Properly update VOPs. * tree-ssa-loop-ivopts.c (get_ref_tag): Remove. (copy_ref_info): Remove memory-tag related code. * tree-call-cdce.c (tree_call_cdce): Rename the VOP. * ipa-pure-const.c (check_decl): Remove memory-tag related code. (check_stmt): Open-code gimple_loaded_syms and gimple_stored_syms computation. * tree-ssa-dom.c (gimple_p): Remove typedef. (eliminate_redundant_computations): Adjust. (record_equivalences_from_stmt): Likewise. (avail_expr_hash): Likewise. (avail_expr_eq): Likewise. * tree-ssa-propagate.c (update_call_from_tree): Properly update VOPs. (stmt_makes_single_load): Likewise. (stmt_makes_single_store): Likewise. * tree-ssa-alias.c: Rewrite completely. (debug_memory_partitions, dump_mem_ref_stats, debug_mem_ref_stats, debug_mem_sym_stats, dump_mem_sym_stats_for_var, debug_all_mem_sym_stats, debug_mp_info, update_mem_sym_stats_from_stmt, delete_mem_ref_stats, create_tag_raw, dump_points_to_info, dump_may_aliases_for, debug_may_aliases_for, new_type_alias): Remove public functions. (pass_reset_cc_flags): Remove. (pass_build_alias): Move ... * tree-ssa-structalias.c (pass_build_alias): ... here. * tree-ssa-alias.c (may_be_aliased): Move ... * tree-flow-inline.h (may_be_aliased): ... here. tree-ssa-alias.c (struct count_ptr_d, count_ptr_derefs, count_uses_and_derefs): Move ... * gimple.c: ... here. * gimple.h (count_uses_and_derefs): Declare. * tree-ssa-alias.c (dump_alias_stats, ptr_deref_may_alias_global_p, ptr_deref_may_alias_decl_p, ptr_derefs_may_alias_p, same_type_for_tbaa, nonaliasing_component_refs_p, decl_refs_may_alias_p, indirect_ref_may_alias_decl_p, indirect_refs_may_alias_p, ref_maybe_used_by_call_p, ref_maybe_used_by_stmt_p, call_may_clobber_ref_p, stmt_may_clobber_ref_p, maybe_skip_until, get_continuation_for_phi, walk_non_aliased_vuses, walk_aliased_vdefs): New functions. * tree-dfa.c (refs_may_alias_p): Move ... * tree-ssa-alias.c (refs_may_alias_p): ... here. Extend. * tree-ssa-alias.h: New file. * tree-ssa-sink.c (is_hidden_global_store): Adjust. (statement_sink_location): Likewise. * opts.c (decode_options): Do not adjust max-aliased-vops or avg-aliased-vops values. * timevar.def (TV_TREE_MAY_ALIAS): Remove. (TV_CALL_CLOBBER): Likewise. (TV_FLOW_SENSITIVE): Likewise. (TV_FLOW_INSENSITIVE): Likewise. (TV_MEMORY_PARTITIONING): Likewise. (TV_ALIAS_STMT_WALK): New timevar. * tree-ssa-loop-ivcanon.c (empty_loop_p): Adjust. * tree-ssa-address.c (create_mem_ref_raw): Use build6. (get_address_description): Remove memory-tag related code. * tree-ssa-ifcombine.c (bb_no_side_effects_p): Adjust. * treestruct.def (TS_MEMORY_TAG, TS_MEMORY_PARTITION_TAG): Remove. * tree-eh.c (cleanup_empty_eh): Do not leave stale SSA_NAMEs and immediate uses in statements. Document. * gimple-pretty-print.c (dump_gimple_mem_ops): Adjust. (dump_symbols): Remove. (dump_gimple_mem_ops): Do not dump loaded or stored syms. * alias.c (get_deref_alias_set): New function split out from ... (get_alias_set): ... here. * alias.h (get_deref_alias_set): Declare. * tree-vect-data-refs.c (vect_create_data_ref_ptr): Remove unused type parameter. Remove restrict pointer handling. Create a ref-all pointer in case type-based alias sets do not conflict. (vect_analyze_data_refs): Remove SMT related code. * tree-vect-stmts.c (vectorizable_store): Re-instantiate TBAA assert. (vectorizable_load): Likewise. * tree-data-ref.h (struct dr_alias): Remove symbol_tag field. (DR_SYMBOL_TAG, DR_VOPS): Remove. * tree-data-ref.c (dr_may_alias_p): Use the alias-oracle. Ignore vops and SMTs. (dr_analyze_alias): Likewise.. (free_data_ref): Likewise. (create_data_ref): Likewise. (analyze_all_data_dependences): Likewise. (get_references_in_stmt): Adjust. * tree-flow-inline.h (gimple_aliases_computed_p, gimple_addressable_vars, gimple_call_clobbered_vars, gimple_call_used_vars, gimple_global_var, may_aliases, memory_partition, factoring_name_p, mark_call_clobbered, clear_call_clobbered, compare_ssa_operands_equal, symbol_mem_tag, set_symbol_mem_tag, gimple_mem_ref_stats): Remove. (gimple_vop): New function. (op_iter_next_use): Remove vuses and mayuses cases. (op_iter_next_def): Remove vdefs case. (op_iter_next_tree): Remove vuses, mayuses and vdefs cases. (clear_and_done_ssa_iter): Do not set removed fields. (op_iter_init): Likewise. Skip vuse and/or vdef if requested. Assert we are not iterating over vuses or vdefs if not also iterating over uses or defs. (op_iter_init_use): Likewise. (op_iter_init_def): Likewise. (op_iter_next_vdef): Remove. (op_iter_next_mustdef): Likewise. (op_iter_init_vdef): Likewise. (compare_ssa_operands_equal): Likewise. (link_use_stmts_after): Handle vuse operand. (is_call_used): Use is_call_clobbered. (is_call_clobbered): Global variables are always call clobbered, query the call-clobbers bitmap. (mark_call_clobbered): Ignore global variables. (clear_call_clobbered): Likewise. * tree-ssa-coalesce.c (create_outofssa_var_map): Adjust virtual operands sanity check. * tree.def (NAME_MEMORY_TAG, SYMBOL_MEMORY_TAG, MEMORY_PARTITION_TAG): Remove. (TARGET_MEM_REF): Remove TMR_TAG operand. * tree-dfa.c (add_referenced_var): Initialize call-clobber state. Remove call-clobber related code. (remove_referenced_var): Likewise. Do not clear mpt or symbol_mem_tag. (dump_variable): Do not dump SMTs, memory stats, may-aliases or partitions or escape reason. (get_single_def_stmt, get_single_def_stmt_from_phi, get_single_def_stmt_with_phi): Remove. (dump_referenced_vars): Tidy. (get_ref_base_and_extent): Allow bare decls. (collect_dfa_stats): Adjust. * graphite.c (rename_variables_in_stmt): Adjust. (graphite_copy_stmts_from_block): Likewise. (translate_clast): Likewise. * tree-ssa-pre.c (struct bb_bitmap_sets): Add expr_dies bitmap. (EXPR_DIES): New. (translate_vuse_through_block): Use the oracle. (phi_translate_1): Adjust. (value_dies_in_block_x): Use the oracle. Cache the outcome in EXPR_DIES. (valid_in_sets): Check if the VUSE for a REFERENCE is available. (eliminate): Do not remove stmts during elimination, instead queue and remove them afterwards. (do_pre): Do not rebuild alias info. (pass_pre): Run TODO_rebuild_alias before PRE. * tree-ssa-live.c (remove_unused_locals): Remove memory-tag code. * tree-sra.c (sra_walk_function): Use gimple_references_memory_p. (mark_all_v_defs_stmt): Remove. (mark_all_v_defs_seq): Adjust. (sra_replace): Likewise. (scalarize_use): Likewise. (scalarize_copy): Likewise. (scalarize_init): Likewise. (scalarize_ldst): Likewise. (todoflags): Remove. (tree_sra): Do not rebuild alias info. (tree_sra_early): Adjust. (pass_sra): Run TODO_update_address_taken before SRA. * tree-predcom.c (set_alias_info): Remove. (prepare_initializers_chain): Do not call it. (mark_virtual_ops_for_renaming): Adjust. (mark_virtual_ops_for_renaming_list): Remove. (initialize_root_vars): Adjust. (initialize_root_vars_lm): Likewise. (prepare_initializers_chain): Likewise. * tree-ssa-copy.c (may_propagate_copy): Remove memory-tag related code. (may_propagate_copy_into_stmt): Likewise. (merge_alias_info): Do nothing for now. (propagate_tree_value_into_stmt): Adjust. (stmt_may_generate_copy): Likewise. * tree-ssa-forwprop.c (tidy_after_forward_propagate_addr): Do not mark symbols for renaming. (forward_propagate_addr_expr): Match up push/pop_stmt_changes with the same statement, make sure to update the new pointed-to one. * tree-ssa-dce.c (eliminate_unnecessary_stmts): Do not copy call statements, do not mark symbols for renaming. (mark_operand_necessary): Dump something. (ref_may_be_aliased): New function. (mark_aliased_reaching_defs_necessary_1): New helper function. (mark_aliased_reaching_defs_necessary): Likewise. (mark_all_reaching_defs_necessary_1): Likewise. (mark_all_reaching_defs_necessary): Likewise. (propagate_necessity): Do not process virtual PHIs. For non-aliased loads mark all reaching definitions as necessary. For aliased loads and stores mark the immediate dominating aliased clobbers as necessary. (visited): New global static. (perform_tree_ssa_dce): Free visited bitmap after propagating necessity. (remove_dead_phis): Perform simple dead virtual PHI removal. (remove_dead_stmt): Properly unlink virtual operands when removing stores. (eliminate_unnecessary_stmts): Schedule PHI removal after stmt removal. * tree-ssa-ter.c (is_replaceable_p): Adjust. (process_replaceable): Likewise. (find_replaceable_in_bb): Likewise. * tree-ssa.c (verify_ssa_name): Verify all VOPs are based on the single gimple vop. (verify_flow_insensitive_alias_info): Remove. (verify_flow_sensitive_alias_info): Likewise. (verify_call_clobbering): Likewise. (verify_memory_partitions): Likewise. (verify_alias_info): Likewise. (verify_ssa): Adjust.. (execute_update_addresses_taken): Export. Update SSA manually. Optimize only when optimizing. Use a local bitmap. (pass_update_address_taken): Remove TODO_update_ssa, add TODO_dump_func. (pass_update_address_taken): Just use TODO_update_address_taken. (init_tree_ssa): Do not initialize addressable_vars. (verify_ssa): Verify new VUSE / VDEF properties. Verify that all stmts definitions have the stmt as SSA_NAME_DEF_STMT. Do not call verify_alias_info. (delete_tree_ssa): Clear the VUSE, VDEF operands. Do not free the loaded and stored syms bitmaps. Reset the escaped and callused solutions. Do not free addressable_vars. Remove memory-tag related code. (warn_uninitialized_var): Aliases are always available. * tree-ssa-loop-prefetch.c (gather_memory_references): Adjust. * lambda-code.c (can_put_in_inner_loop): Adjust. (can_put_after_inner_loop): Likewise. (perfect_nestify): Likewise. * tree-vect-stmts.c (vect_stmt_relevant_p): Adjust. (vect_gen_widened_results_half): Remove CALL_EXPR handling. (vectorizable_conversion): Do not mark symbols for renaming. * tree-inline.c (remap_gimple_stmt): Clear VUSE/VDEF. (expand_call_inline): Unlink the calls virtual operands before replacing it. (tree_function_versioning): Do not call update_ssa if we are not updating clones. Simplify. * tree-ssa-phiprop.c (phivn_valid_p): Adjust. (propagate_with_phi): Likewise.. * tree-outof-ssa.c (create_temp): Remove memory tag and call clobber code. Assert we are not aliased or global. * tree-flow.h: Include tree-ssa-alias.h (enum escape_type): Remove. (struct mem_sym_stats_d): Likewise. (struct mem_ref_stats_d): Likewise. (struct gimple_df): Add vop member. Remove global_var, call_clobbered_vars, call_used_vars, addressable_vars, aliases_compted_p and mem_ref_stats members. Add syms_to_rename, escaped and callused members. (struct ptr_info_def): Remove all members, add points-to solution member pt. (struct var_ann_d): Remove in_vuse_list, in_vdef_list, call_clobbered, escape_mask, mpt and symbol_mem_tag members. * Makefile.in (TREE_FLOW_H): Add tree-ssa-alias.h. (tree-ssa-structalias.o): Remove tree-ssa-structalias.h. (tree-ssa-alias.o): Likewise. (toplev.o): Add tree-ssa-alias.h (GTFILES): Remove tree-ssa-structalias.h, add tree-ssa-alias.h. * gimple.c (gimple_set_bb): Fix off-by-one error. (is_gimple_reg): Do not handle memory tags. (gimple_copy): Also copy virtual operands. Delay updating the statement. Do not reset loaded and stored syms. (gimple_set_stored_syms): Remove. (gimple_set_loaded_syms): Likewise. (gimple_call_copy_skip_args): Copy the virtual operands and mark the new statement modified. * tree-ssa-structalias.c (may_alias_p): Remove. (set_uids_in_ptset): Take the alias set to prune with as parameter. Fold in the alias test of may_alias_p. (compute_points_to_sets): Compute whether a ptr is dereferenced in a local sbitmap. (process_constraint): Deal with &ANYTHING on the lhs, reject all other ADDRESSOF constraints on the lhs. (get_constraint_for_component_ref): Assert that we don't get ADDRESSOF constraints from the base of the reference. Properly generate UNKNOWN_OFFSET for DEREF if needed. (struct variable_info): Remove collapsed_to member. (get_varinfo_fc): Remove. (new_var_info): Do not set collapsed_to. (dump_constraint): Do not follow cycles. (dump_constraint_graph): Likewise. (build_pred_graph): Likewise. (build_succ_graph): Likewise. (rewrite_constraints): Likewise. (do_simple_structure_copy): Remove. (do_rhs_deref_structure_copy): Remove. (do_lhs_deref_structure_copy): Remove. (collapse_rest_of_var): Remove. (do_structure_copy): Re-implement. (pta_stats): New global variable. (dump_pta_stats): New function. (struct constraint_expr): Make offset signed. (UNKNOWN_OFFSET): Define special value. (dump_constraint): Dump UNKNOWN_OFFSET as UNKNOWN. (solution_set_expand): New helper function split out from ... (do_sd_constraint): ... here. (solution_set_add): Handle UNKNOWN_OFFSET. Handle negative offsets. (do_ds_constraint): Likewise. (do_sd_constraint): Likewise. Do not special-case ESCAPED = *ESCAPED and CALLUSED = *CALLUSED. (set_union_with_increment): Make inc argument signed. (type_safe): Remove. (get_constraint_for_ptr_offset): Handle unknown and negative constant offsets. (first_vi_for_offset): Handle offsets before start. Bail out early for offsets beyond the variable extent. (first_or_preceding_vi_for_offset): New function. (init_base_vars): Add ESCAPED = ESCAPED + UNKNOWN_OFFSET constraint. Together with ESCAPED = *ESCAPED this properly computes reachability. (find_what_var_points_to): New function. (find_what_p_points_to): Implement in terms of find_what_var_points_to. (pt_solution_reset, pt_solution_empty_p, pt_solution_includes_global, pt_solution_includes_1, pt_solution_includes, pt_solutions_intersect_1, pt_solutions_intersect): New functions. (compute_call_used_vars): Remove. (compute_may_aliases): New main entry into PTA computation. * gimple.h (gimple_p): New typedef. (struct gimple_statement_base): Remove references_memory_p. (struct gimple_statement_with_memory_ops_base): Remove vdef_ops, vuse_ops, stores and loads members. Add vdef and vuse members. (gimple_vuse_ops, gimple_set_vuse_ops, gimple_vdef_ops, gimple_set_vdef_ops, gimple_loaded_syms, gimple_stored_syms, gimple_set_references_memory): Remove. (gimple_vuse_op, gimple_vdef_op, gimple_vuse, gimple_vdef, gimple_vuse_ptr, gimple_vdef_ptri, gimple_set_vuse, gimple_set_vdef): New functions. * tree-cfg.c (move_block_to_fn): Fix off-by-one error. (verify_expr): Allow RESULT_DECL. (gimple_duplicate_bb): Do not copy virtual operands. (gimple_duplicate_sese_region): Adjust. (gimple_duplicate_sese_tail): Likewise. (mark_virtual_ops_in_region): Remove. (move_sese_region_to_fn): Do not call it. * passes.c (init_optimization_passes): Remove pass_reset_cc_flags and pass_simple_dse. (execute_function_todo): Handle TODO_update_address_taken, call execute_update_addresses_taken for TODO_rebuild_alias. (execute_todo): Adjust. (execute_one_pass): Init dump files early. * ipa-struct-reorg.c (finalize_var_creation): Do not mark vars call-clobbered. (create_general_new_stmt): Clear vops. * tree-ssa-reassoc.c (get_rank): Adjust. * tree-vect-slp.c (vect_create_mask_and_perm): Do not mark symbols for renaming. * params.def (PARAM_MAX_ALIASED_VOPS): Remove. (PARAM_AVG_ALIASED_VOPS): Likewise. * tree-ssanames.c (init_ssanames): Allocate SYMS_TO_RENAME. (duplicate_ssa_name_ptr_info): No need to copy the shared bitmaps. * tree-ssa-operands.c: Simplify for new virtual operand representation. (operand_build_cmp, copy_virtual_operands, create_ssa_artificial_load_stmt, add_to_addressable_set, gimple_add_to_addresses_taken): Remove public functions. (unlink_stmt_vdef): New function. * gcc.dg/pr19633-1.c: Adjust. * gcc.dg/torture/pta-callused-1.c: Likewise. * gcc.dg/torture/pr39074-2.c: Likewise. * gcc.dg/torture/pr39074.c: Likewise. * gcc.dg/torture/pta-ptrarith-3.c: New testcase. * gcc.dg/torture/pr30375.c: Adjust. * gcc.dg/torture/pr33563.c: Likewise. * gcc.dg/torture/pr33870.c: Likewise. * gcc.dg/torture/pr33560.c: Likewise. * gcc.dg/torture/pta-structcopy-1.c: New testcase. * gcc.dg/torture/ssa-pta-fn-1.c: Likewise. * gcc.dg/tree-ssa/alias-15.c: Remove. * gcc.dg/tree-ssa/ssa-dce-4.c: New testcase. * gcc.dg/tree-ssa/pr26421.c: Adjust. * gcc.dg/tree-ssa/ssa-fre-10.c: XFAIL. * gcc.dg/tree-ssa/ssa-dce-5.c: New testcase. * gcc.dg/tree-ssa/pr23382.c: Adjust. * gcc.dg/tree-ssa/ssa-fre-20.c: New testcase. * gcc.dg/tree-ssa/alias-16.c: Adjust. * gcc.dg/tree-ssa/ssa-fre-13.c: Likewise. * gcc.dg/tree-ssa/ssa-fre-14.c: Likewise. * gcc.dg/tree-ssa/alias-18.c: Likewise. * gcc.dg/tree-ssa/ssa-fre-15.c: Likewise. * gcc.dg/tree-ssa/ssa-lim-3.c: Likewise. * gcc.dg/tree-ssa/alias-19.c: Likewise. * gcc.dg/tree-ssa/pta-ptrarith-1.c: New testcase. * gcc.dg/tree-ssa/pr13146.c: Likewise. * gcc.dg/tree-ssa/ssa-pre-23.c: Likewise. * gcc.dg/tree-ssa/pta-ptrarith-2.c: Likewise. * gcc.dg/tree-ssa/ssa-fre-18.c: Likewise. * gcc.dg/tree-ssa/ssa-pre-24.c: New XFAILed testcase. * gcc.dg/tree-ssa/ssa-fre-19.c: New testcase. * gcc.dg/tree-ssa/alias-20.c: Likewise. * gcc.dg/tree-ssa/ssa-dse-12.c: Likewise. * gcc.dg/tree-ssa/pr38895.c: Likewise. * gcc.dg/uninit-B.c: XFAIL. * gcc.dg/vect/no-vfa-vect-43.c: Adjust. * gcc.dg/uninit-pr19430.c: XFAIL. * g++.dg/tree-ssa/pr13146.C: New testcase. * g++.dg/opt/pr36187.C: Adjust. * g++.dg/torture/20090329-1.C: New testcase. From-SVN: r145494
1602 lines
46 KiB
C
1602 lines
46 KiB
C
/* Array prefetching.
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Copyright (C) 2005, 2007, 2008 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 3, or (at your option) any
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later version.
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GCC is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tree.h"
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#include "rtl.h"
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#include "tm_p.h"
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#include "hard-reg-set.h"
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#include "basic-block.h"
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#include "output.h"
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#include "diagnostic.h"
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#include "tree-flow.h"
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#include "tree-dump.h"
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#include "timevar.h"
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#include "cfgloop.h"
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#include "varray.h"
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#include "expr.h"
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#include "tree-pass.h"
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#include "ggc.h"
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#include "insn-config.h"
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#include "recog.h"
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#include "hashtab.h"
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#include "tree-chrec.h"
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#include "tree-scalar-evolution.h"
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#include "toplev.h"
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#include "params.h"
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#include "langhooks.h"
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#include "tree-inline.h"
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#include "tree-data-ref.h"
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#include "optabs.h"
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/* This pass inserts prefetch instructions to optimize cache usage during
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accesses to arrays in loops. It processes loops sequentially and:
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1) Gathers all memory references in the single loop.
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2) For each of the references it decides when it is profitable to prefetch
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it. To do it, we evaluate the reuse among the accesses, and determines
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two values: PREFETCH_BEFORE (meaning that it only makes sense to do
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prefetching in the first PREFETCH_BEFORE iterations of the loop) and
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PREFETCH_MOD (meaning that it only makes sense to prefetch in the
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iterations of the loop that are zero modulo PREFETCH_MOD). For example
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(assuming cache line size is 64 bytes, char has size 1 byte and there
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is no hardware sequential prefetch):
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char *a;
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for (i = 0; i < max; i++)
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{
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a[255] = ...; (0)
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a[i] = ...; (1)
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a[i + 64] = ...; (2)
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a[16*i] = ...; (3)
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a[187*i] = ...; (4)
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a[187*i + 50] = ...; (5)
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}
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(0) obviously has PREFETCH_BEFORE 1
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(1) has PREFETCH_BEFORE 64, since (2) accesses the same memory
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location 64 iterations before it, and PREFETCH_MOD 64 (since
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it hits the same cache line otherwise).
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(2) has PREFETCH_MOD 64
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(3) has PREFETCH_MOD 4
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(4) has PREFETCH_MOD 1. We do not set PREFETCH_BEFORE here, since
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the cache line accessed by (4) is the same with probability only
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7/32.
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(5) has PREFETCH_MOD 1 as well.
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Additionally, we use data dependence analysis to determine for each
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reference the distance till the first reuse; this information is used
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to determine the temporality of the issued prefetch instruction.
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3) We determine how much ahead we need to prefetch. The number of
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iterations needed is time to fetch / time spent in one iteration of
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the loop. The problem is that we do not know either of these values,
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so we just make a heuristic guess based on a magic (possibly)
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target-specific constant and size of the loop.
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4) Determine which of the references we prefetch. We take into account
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that there is a maximum number of simultaneous prefetches (provided
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by machine description). We prefetch as many prefetches as possible
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while still within this bound (starting with those with lowest
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prefetch_mod, since they are responsible for most of the cache
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misses).
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5) We unroll and peel loops so that we are able to satisfy PREFETCH_MOD
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and PREFETCH_BEFORE requirements (within some bounds), and to avoid
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prefetching nonaccessed memory.
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TODO -- actually implement peeling.
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6) We actually emit the prefetch instructions. ??? Perhaps emit the
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prefetch instructions with guards in cases where 5) was not sufficient
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to satisfy the constraints?
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Some other TODO:
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-- write and use more general reuse analysis (that could be also used
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in other cache aimed loop optimizations)
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-- make it behave sanely together with the prefetches given by user
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(now we just ignore them; at the very least we should avoid
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optimizing loops in that user put his own prefetches)
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-- we assume cache line size alignment of arrays; this could be
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improved. */
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/* Magic constants follow. These should be replaced by machine specific
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numbers. */
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/* True if write can be prefetched by a read prefetch. */
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#ifndef WRITE_CAN_USE_READ_PREFETCH
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#define WRITE_CAN_USE_READ_PREFETCH 1
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#endif
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/* True if read can be prefetched by a write prefetch. */
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#ifndef READ_CAN_USE_WRITE_PREFETCH
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#define READ_CAN_USE_WRITE_PREFETCH 0
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#endif
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/* The size of the block loaded by a single prefetch. Usually, this is
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the same as cache line size (at the moment, we only consider one level
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of cache hierarchy). */
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#ifndef PREFETCH_BLOCK
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#define PREFETCH_BLOCK L1_CACHE_LINE_SIZE
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#endif
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/* Do we have a forward hardware sequential prefetching? */
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#ifndef HAVE_FORWARD_PREFETCH
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#define HAVE_FORWARD_PREFETCH 0
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#endif
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/* Do we have a backward hardware sequential prefetching? */
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#ifndef HAVE_BACKWARD_PREFETCH
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#define HAVE_BACKWARD_PREFETCH 0
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#endif
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/* In some cases we are only able to determine that there is a certain
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probability that the two accesses hit the same cache line. In this
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case, we issue the prefetches for both of them if this probability
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is less then (1000 - ACCEPTABLE_MISS_RATE) per thousand. */
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#ifndef ACCEPTABLE_MISS_RATE
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#define ACCEPTABLE_MISS_RATE 50
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#endif
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#ifndef HAVE_prefetch
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#define HAVE_prefetch 0
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#endif
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#define L1_CACHE_SIZE_BYTES ((unsigned) (L1_CACHE_SIZE * 1024))
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#define L2_CACHE_SIZE_BYTES ((unsigned) (L2_CACHE_SIZE * 1024))
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/* We consider a memory access nontemporal if it is not reused sooner than
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after L2_CACHE_SIZE_BYTES of memory are accessed. However, we ignore
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accesses closer than L1_CACHE_SIZE_BYTES / NONTEMPORAL_FRACTION,
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so that we use nontemporal prefetches e.g. if single memory location
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is accessed several times in a single iteration of the loop. */
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#define NONTEMPORAL_FRACTION 16
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/* In case we have to emit a memory fence instruction after the loop that
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uses nontemporal stores, this defines the builtin to use. */
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#ifndef FENCE_FOLLOWING_MOVNT
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#define FENCE_FOLLOWING_MOVNT NULL_TREE
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#endif
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/* The group of references between that reuse may occur. */
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struct mem_ref_group
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{
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tree base; /* Base of the reference. */
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HOST_WIDE_INT step; /* Step of the reference. */
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struct mem_ref *refs; /* References in the group. */
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struct mem_ref_group *next; /* Next group of references. */
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};
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/* Assigned to PREFETCH_BEFORE when all iterations are to be prefetched. */
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#define PREFETCH_ALL (~(unsigned HOST_WIDE_INT) 0)
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/* The memory reference. */
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struct mem_ref
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{
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gimple stmt; /* Statement in that the reference appears. */
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tree mem; /* The reference. */
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HOST_WIDE_INT delta; /* Constant offset of the reference. */
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struct mem_ref_group *group; /* The group of references it belongs to. */
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unsigned HOST_WIDE_INT prefetch_mod;
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/* Prefetch only each PREFETCH_MOD-th
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iteration. */
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unsigned HOST_WIDE_INT prefetch_before;
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/* Prefetch only first PREFETCH_BEFORE
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iterations. */
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unsigned reuse_distance; /* The amount of data accessed before the first
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reuse of this value. */
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struct mem_ref *next; /* The next reference in the group. */
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unsigned write_p : 1; /* Is it a write? */
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unsigned independent_p : 1; /* True if the reference is independent on
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all other references inside the loop. */
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unsigned issue_prefetch_p : 1; /* Should we really issue the prefetch? */
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unsigned storent_p : 1; /* True if we changed the store to a
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nontemporal one. */
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};
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/* Dumps information about reference REF to FILE. */
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static void
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dump_mem_ref (FILE *file, struct mem_ref *ref)
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{
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fprintf (file, "Reference %p:\n", (void *) ref);
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fprintf (file, " group %p (base ", (void *) ref->group);
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print_generic_expr (file, ref->group->base, TDF_SLIM);
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fprintf (file, ", step ");
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fprintf (file, HOST_WIDE_INT_PRINT_DEC, ref->group->step);
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fprintf (file, ")\n");
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fprintf (file, " delta ");
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fprintf (file, HOST_WIDE_INT_PRINT_DEC, ref->delta);
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fprintf (file, "\n");
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fprintf (file, " %s\n", ref->write_p ? "write" : "read");
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fprintf (file, "\n");
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}
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/* Finds a group with BASE and STEP in GROUPS, or creates one if it does not
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exist. */
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static struct mem_ref_group *
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find_or_create_group (struct mem_ref_group **groups, tree base,
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HOST_WIDE_INT step)
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{
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struct mem_ref_group *group;
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for (; *groups; groups = &(*groups)->next)
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{
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if ((*groups)->step == step
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&& operand_equal_p ((*groups)->base, base, 0))
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return *groups;
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/* Keep the list of groups sorted by decreasing step. */
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if ((*groups)->step < step)
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break;
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}
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group = XNEW (struct mem_ref_group);
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group->base = base;
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group->step = step;
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group->refs = NULL;
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group->next = *groups;
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*groups = group;
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return group;
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}
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/* Records a memory reference MEM in GROUP with offset DELTA and write status
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WRITE_P. The reference occurs in statement STMT. */
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static void
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record_ref (struct mem_ref_group *group, gimple stmt, tree mem,
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HOST_WIDE_INT delta, bool write_p)
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{
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struct mem_ref **aref;
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/* Do not record the same address twice. */
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for (aref = &group->refs; *aref; aref = &(*aref)->next)
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{
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/* It does not have to be possible for write reference to reuse the read
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prefetch, or vice versa. */
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if (!WRITE_CAN_USE_READ_PREFETCH
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&& write_p
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&& !(*aref)->write_p)
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continue;
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if (!READ_CAN_USE_WRITE_PREFETCH
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&& !write_p
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&& (*aref)->write_p)
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continue;
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if ((*aref)->delta == delta)
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return;
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}
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(*aref) = XNEW (struct mem_ref);
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(*aref)->stmt = stmt;
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(*aref)->mem = mem;
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(*aref)->delta = delta;
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(*aref)->write_p = write_p;
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(*aref)->prefetch_before = PREFETCH_ALL;
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(*aref)->prefetch_mod = 1;
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(*aref)->reuse_distance = 0;
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(*aref)->issue_prefetch_p = false;
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(*aref)->group = group;
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(*aref)->next = NULL;
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(*aref)->independent_p = false;
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(*aref)->storent_p = false;
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if (dump_file && (dump_flags & TDF_DETAILS))
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dump_mem_ref (dump_file, *aref);
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}
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/* Release memory references in GROUPS. */
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static void
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release_mem_refs (struct mem_ref_group *groups)
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{
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struct mem_ref_group *next_g;
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struct mem_ref *ref, *next_r;
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for (; groups; groups = next_g)
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{
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next_g = groups->next;
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for (ref = groups->refs; ref; ref = next_r)
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{
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next_r = ref->next;
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free (ref);
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}
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free (groups);
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}
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}
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/* A structure used to pass arguments to idx_analyze_ref. */
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struct ar_data
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{
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struct loop *loop; /* Loop of the reference. */
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gimple stmt; /* Statement of the reference. */
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HOST_WIDE_INT *step; /* Step of the memory reference. */
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HOST_WIDE_INT *delta; /* Offset of the memory reference. */
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};
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/* Analyzes a single INDEX of a memory reference to obtain information
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described at analyze_ref. Callback for for_each_index. */
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static bool
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idx_analyze_ref (tree base, tree *index, void *data)
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{
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struct ar_data *ar_data = (struct ar_data *) data;
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tree ibase, step, stepsize;
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HOST_WIDE_INT istep, idelta = 0, imult = 1;
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affine_iv iv;
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if (TREE_CODE (base) == MISALIGNED_INDIRECT_REF
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|| TREE_CODE (base) == ALIGN_INDIRECT_REF)
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return false;
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if (!simple_iv (ar_data->loop, loop_containing_stmt (ar_data->stmt),
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*index, &iv, false))
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return false;
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ibase = iv.base;
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step = iv.step;
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if (!cst_and_fits_in_hwi (step))
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return false;
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istep = int_cst_value (step);
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if (TREE_CODE (ibase) == POINTER_PLUS_EXPR
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&& cst_and_fits_in_hwi (TREE_OPERAND (ibase, 1)))
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{
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idelta = int_cst_value (TREE_OPERAND (ibase, 1));
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ibase = TREE_OPERAND (ibase, 0);
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}
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if (cst_and_fits_in_hwi (ibase))
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{
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idelta += int_cst_value (ibase);
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ibase = build_int_cst (TREE_TYPE (ibase), 0);
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}
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if (TREE_CODE (base) == ARRAY_REF)
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{
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stepsize = array_ref_element_size (base);
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if (!cst_and_fits_in_hwi (stepsize))
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return false;
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imult = int_cst_value (stepsize);
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istep *= imult;
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idelta *= imult;
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}
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*ar_data->step += istep;
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*ar_data->delta += idelta;
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*index = ibase;
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return true;
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}
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|
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/* Tries to express REF_P in shape &BASE + STEP * iter + DELTA, where DELTA and
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STEP are integer constants and iter is number of iterations of LOOP. The
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reference occurs in statement STMT. Strips nonaddressable component
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references from REF_P. */
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static bool
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analyze_ref (struct loop *loop, tree *ref_p, tree *base,
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HOST_WIDE_INT *step, HOST_WIDE_INT *delta,
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gimple stmt)
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{
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struct ar_data ar_data;
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tree off;
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HOST_WIDE_INT bit_offset;
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tree ref = *ref_p;
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*step = 0;
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*delta = 0;
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|
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/* First strip off the component references. Ignore bitfields. */
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if (TREE_CODE (ref) == COMPONENT_REF
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&& DECL_NONADDRESSABLE_P (TREE_OPERAND (ref, 1)))
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ref = TREE_OPERAND (ref, 0);
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|
|
|
*ref_p = ref;
|
|
|
|
for (; TREE_CODE (ref) == COMPONENT_REF; ref = TREE_OPERAND (ref, 0))
|
|
{
|
|
off = DECL_FIELD_BIT_OFFSET (TREE_OPERAND (ref, 1));
|
|
bit_offset = TREE_INT_CST_LOW (off);
|
|
gcc_assert (bit_offset % BITS_PER_UNIT == 0);
|
|
|
|
*delta += bit_offset / BITS_PER_UNIT;
|
|
}
|
|
|
|
*base = unshare_expr (ref);
|
|
ar_data.loop = loop;
|
|
ar_data.stmt = stmt;
|
|
ar_data.step = step;
|
|
ar_data.delta = delta;
|
|
return for_each_index (base, idx_analyze_ref, &ar_data);
|
|
}
|
|
|
|
/* Record a memory reference REF to the list REFS. The reference occurs in
|
|
LOOP in statement STMT and it is write if WRITE_P. Returns true if the
|
|
reference was recorded, false otherwise. */
|
|
|
|
static bool
|
|
gather_memory_references_ref (struct loop *loop, struct mem_ref_group **refs,
|
|
tree ref, bool write_p, gimple stmt)
|
|
{
|
|
tree base;
|
|
HOST_WIDE_INT step, delta;
|
|
struct mem_ref_group *agrp;
|
|
|
|
if (get_base_address (ref) == NULL)
|
|
return false;
|
|
|
|
if (!analyze_ref (loop, &ref, &base, &step, &delta, stmt))
|
|
return false;
|
|
|
|
/* Now we know that REF = &BASE + STEP * iter + DELTA, where DELTA and STEP
|
|
are integer constants. */
|
|
agrp = find_or_create_group (refs, base, step);
|
|
record_ref (agrp, stmt, ref, delta, write_p);
|
|
|
|
return true;
|
|
}
|
|
|
|
/* Record the suitable memory references in LOOP. NO_OTHER_REFS is set to
|
|
true if there are no other memory references inside the loop. */
|
|
|
|
static struct mem_ref_group *
|
|
gather_memory_references (struct loop *loop, bool *no_other_refs)
|
|
{
|
|
basic_block *body = get_loop_body_in_dom_order (loop);
|
|
basic_block bb;
|
|
unsigned i;
|
|
gimple_stmt_iterator bsi;
|
|
gimple stmt;
|
|
tree lhs, rhs;
|
|
struct mem_ref_group *refs = NULL;
|
|
|
|
*no_other_refs = true;
|
|
|
|
/* Scan the loop body in order, so that the former references precede the
|
|
later ones. */
|
|
for (i = 0; i < loop->num_nodes; i++)
|
|
{
|
|
bb = body[i];
|
|
if (bb->loop_father != loop)
|
|
continue;
|
|
|
|
for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
|
|
{
|
|
stmt = gsi_stmt (bsi);
|
|
|
|
if (gimple_code (stmt) != GIMPLE_ASSIGN)
|
|
{
|
|
if (gimple_vuse (stmt)
|
|
|| (is_gimple_call (stmt)
|
|
&& !(gimple_call_flags (stmt) & ECF_CONST)))
|
|
*no_other_refs = false;
|
|
continue;
|
|
}
|
|
|
|
lhs = gimple_assign_lhs (stmt);
|
|
rhs = gimple_assign_rhs1 (stmt);
|
|
|
|
if (REFERENCE_CLASS_P (rhs))
|
|
*no_other_refs &= gather_memory_references_ref (loop, &refs,
|
|
rhs, false, stmt);
|
|
if (REFERENCE_CLASS_P (lhs))
|
|
*no_other_refs &= gather_memory_references_ref (loop, &refs,
|
|
lhs, true, stmt);
|
|
}
|
|
}
|
|
free (body);
|
|
|
|
return refs;
|
|
}
|
|
|
|
/* Prune the prefetch candidate REF using the self-reuse. */
|
|
|
|
static void
|
|
prune_ref_by_self_reuse (struct mem_ref *ref)
|
|
{
|
|
HOST_WIDE_INT step = ref->group->step;
|
|
bool backward = step < 0;
|
|
|
|
if (step == 0)
|
|
{
|
|
/* Prefetch references to invariant address just once. */
|
|
ref->prefetch_before = 1;
|
|
return;
|
|
}
|
|
|
|
if (backward)
|
|
step = -step;
|
|
|
|
if (step > PREFETCH_BLOCK)
|
|
return;
|
|
|
|
if ((backward && HAVE_BACKWARD_PREFETCH)
|
|
|| (!backward && HAVE_FORWARD_PREFETCH))
|
|
{
|
|
ref->prefetch_before = 1;
|
|
return;
|
|
}
|
|
|
|
ref->prefetch_mod = PREFETCH_BLOCK / step;
|
|
}
|
|
|
|
/* Divides X by BY, rounding down. */
|
|
|
|
static HOST_WIDE_INT
|
|
ddown (HOST_WIDE_INT x, unsigned HOST_WIDE_INT by)
|
|
{
|
|
gcc_assert (by > 0);
|
|
|
|
if (x >= 0)
|
|
return x / by;
|
|
else
|
|
return (x + by - 1) / by;
|
|
}
|
|
|
|
/* Prune the prefetch candidate REF using the reuse with BY.
|
|
If BY_IS_BEFORE is true, BY is before REF in the loop. */
|
|
|
|
static void
|
|
prune_ref_by_group_reuse (struct mem_ref *ref, struct mem_ref *by,
|
|
bool by_is_before)
|
|
{
|
|
HOST_WIDE_INT step = ref->group->step;
|
|
bool backward = step < 0;
|
|
HOST_WIDE_INT delta_r = ref->delta, delta_b = by->delta;
|
|
HOST_WIDE_INT delta = delta_b - delta_r;
|
|
HOST_WIDE_INT hit_from;
|
|
unsigned HOST_WIDE_INT prefetch_before, prefetch_block;
|
|
|
|
if (delta == 0)
|
|
{
|
|
/* If the references has the same address, only prefetch the
|
|
former. */
|
|
if (by_is_before)
|
|
ref->prefetch_before = 0;
|
|
|
|
return;
|
|
}
|
|
|
|
if (!step)
|
|
{
|
|
/* If the reference addresses are invariant and fall into the
|
|
same cache line, prefetch just the first one. */
|
|
if (!by_is_before)
|
|
return;
|
|
|
|
if (ddown (ref->delta, PREFETCH_BLOCK)
|
|
!= ddown (by->delta, PREFETCH_BLOCK))
|
|
return;
|
|
|
|
ref->prefetch_before = 0;
|
|
return;
|
|
}
|
|
|
|
/* Only prune the reference that is behind in the array. */
|
|
if (backward)
|
|
{
|
|
if (delta > 0)
|
|
return;
|
|
|
|
/* Transform the data so that we may assume that the accesses
|
|
are forward. */
|
|
delta = - delta;
|
|
step = -step;
|
|
delta_r = PREFETCH_BLOCK - 1 - delta_r;
|
|
delta_b = PREFETCH_BLOCK - 1 - delta_b;
|
|
}
|
|
else
|
|
{
|
|
if (delta < 0)
|
|
return;
|
|
}
|
|
|
|
/* Check whether the two references are likely to hit the same cache
|
|
line, and how distant the iterations in that it occurs are from
|
|
each other. */
|
|
|
|
if (step <= PREFETCH_BLOCK)
|
|
{
|
|
/* The accesses are sure to meet. Let us check when. */
|
|
hit_from = ddown (delta_b, PREFETCH_BLOCK) * PREFETCH_BLOCK;
|
|
prefetch_before = (hit_from - delta_r + step - 1) / step;
|
|
|
|
if (prefetch_before < ref->prefetch_before)
|
|
ref->prefetch_before = prefetch_before;
|
|
|
|
return;
|
|
}
|
|
|
|
/* A more complicated case. First let us ensure that size of cache line
|
|
and step are coprime (here we assume that PREFETCH_BLOCK is a power
|
|
of two. */
|
|
prefetch_block = PREFETCH_BLOCK;
|
|
while ((step & 1) == 0
|
|
&& prefetch_block > 1)
|
|
{
|
|
step >>= 1;
|
|
prefetch_block >>= 1;
|
|
delta >>= 1;
|
|
}
|
|
|
|
/* Now step > prefetch_block, and step and prefetch_block are coprime.
|
|
Determine the probability that the accesses hit the same cache line. */
|
|
|
|
prefetch_before = delta / step;
|
|
delta %= step;
|
|
if ((unsigned HOST_WIDE_INT) delta
|
|
<= (prefetch_block * ACCEPTABLE_MISS_RATE / 1000))
|
|
{
|
|
if (prefetch_before < ref->prefetch_before)
|
|
ref->prefetch_before = prefetch_before;
|
|
|
|
return;
|
|
}
|
|
|
|
/* Try also the following iteration. */
|
|
prefetch_before++;
|
|
delta = step - delta;
|
|
if ((unsigned HOST_WIDE_INT) delta
|
|
<= (prefetch_block * ACCEPTABLE_MISS_RATE / 1000))
|
|
{
|
|
if (prefetch_before < ref->prefetch_before)
|
|
ref->prefetch_before = prefetch_before;
|
|
|
|
return;
|
|
}
|
|
|
|
/* The ref probably does not reuse by. */
|
|
return;
|
|
}
|
|
|
|
/* Prune the prefetch candidate REF using the reuses with other references
|
|
in REFS. */
|
|
|
|
static void
|
|
prune_ref_by_reuse (struct mem_ref *ref, struct mem_ref *refs)
|
|
{
|
|
struct mem_ref *prune_by;
|
|
bool before = true;
|
|
|
|
prune_ref_by_self_reuse (ref);
|
|
|
|
for (prune_by = refs; prune_by; prune_by = prune_by->next)
|
|
{
|
|
if (prune_by == ref)
|
|
{
|
|
before = false;
|
|
continue;
|
|
}
|
|
|
|
if (!WRITE_CAN_USE_READ_PREFETCH
|
|
&& ref->write_p
|
|
&& !prune_by->write_p)
|
|
continue;
|
|
if (!READ_CAN_USE_WRITE_PREFETCH
|
|
&& !ref->write_p
|
|
&& prune_by->write_p)
|
|
continue;
|
|
|
|
prune_ref_by_group_reuse (ref, prune_by, before);
|
|
}
|
|
}
|
|
|
|
/* Prune the prefetch candidates in GROUP using the reuse analysis. */
|
|
|
|
static void
|
|
prune_group_by_reuse (struct mem_ref_group *group)
|
|
{
|
|
struct mem_ref *ref_pruned;
|
|
|
|
for (ref_pruned = group->refs; ref_pruned; ref_pruned = ref_pruned->next)
|
|
{
|
|
prune_ref_by_reuse (ref_pruned, group->refs);
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "Reference %p:", (void *) ref_pruned);
|
|
|
|
if (ref_pruned->prefetch_before == PREFETCH_ALL
|
|
&& ref_pruned->prefetch_mod == 1)
|
|
fprintf (dump_file, " no restrictions");
|
|
else if (ref_pruned->prefetch_before == 0)
|
|
fprintf (dump_file, " do not prefetch");
|
|
else if (ref_pruned->prefetch_before <= ref_pruned->prefetch_mod)
|
|
fprintf (dump_file, " prefetch once");
|
|
else
|
|
{
|
|
if (ref_pruned->prefetch_before != PREFETCH_ALL)
|
|
{
|
|
fprintf (dump_file, " prefetch before ");
|
|
fprintf (dump_file, HOST_WIDE_INT_PRINT_DEC,
|
|
ref_pruned->prefetch_before);
|
|
}
|
|
if (ref_pruned->prefetch_mod != 1)
|
|
{
|
|
fprintf (dump_file, " prefetch mod ");
|
|
fprintf (dump_file, HOST_WIDE_INT_PRINT_DEC,
|
|
ref_pruned->prefetch_mod);
|
|
}
|
|
}
|
|
fprintf (dump_file, "\n");
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Prune the list of prefetch candidates GROUPS using the reuse analysis. */
|
|
|
|
static void
|
|
prune_by_reuse (struct mem_ref_group *groups)
|
|
{
|
|
for (; groups; groups = groups->next)
|
|
prune_group_by_reuse (groups);
|
|
}
|
|
|
|
/* Returns true if we should issue prefetch for REF. */
|
|
|
|
static bool
|
|
should_issue_prefetch_p (struct mem_ref *ref)
|
|
{
|
|
/* For now do not issue prefetches for only first few of the
|
|
iterations. */
|
|
if (ref->prefetch_before != PREFETCH_ALL)
|
|
return false;
|
|
|
|
/* Do not prefetch nontemporal stores. */
|
|
if (ref->storent_p)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/* Decide which of the prefetch candidates in GROUPS to prefetch.
|
|
AHEAD is the number of iterations to prefetch ahead (which corresponds
|
|
to the number of simultaneous instances of one prefetch running at a
|
|
time). UNROLL_FACTOR is the factor by that the loop is going to be
|
|
unrolled. Returns true if there is anything to prefetch. */
|
|
|
|
static bool
|
|
schedule_prefetches (struct mem_ref_group *groups, unsigned unroll_factor,
|
|
unsigned ahead)
|
|
{
|
|
unsigned remaining_prefetch_slots, n_prefetches, prefetch_slots;
|
|
unsigned slots_per_prefetch;
|
|
struct mem_ref *ref;
|
|
bool any = false;
|
|
|
|
/* At most SIMULTANEOUS_PREFETCHES should be running at the same time. */
|
|
remaining_prefetch_slots = SIMULTANEOUS_PREFETCHES;
|
|
|
|
/* The prefetch will run for AHEAD iterations of the original loop, i.e.,
|
|
AHEAD / UNROLL_FACTOR iterations of the unrolled loop. In each iteration,
|
|
it will need a prefetch slot. */
|
|
slots_per_prefetch = (ahead + unroll_factor / 2) / unroll_factor;
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Each prefetch instruction takes %u prefetch slots.\n",
|
|
slots_per_prefetch);
|
|
|
|
/* For now we just take memory references one by one and issue
|
|
prefetches for as many as possible. The groups are sorted
|
|
starting with the largest step, since the references with
|
|
large step are more likely to cause many cache misses. */
|
|
|
|
for (; groups; groups = groups->next)
|
|
for (ref = groups->refs; ref; ref = ref->next)
|
|
{
|
|
if (!should_issue_prefetch_p (ref))
|
|
continue;
|
|
|
|
/* If we need to prefetch the reference each PREFETCH_MOD iterations,
|
|
and we unroll the loop UNROLL_FACTOR times, we need to insert
|
|
ceil (UNROLL_FACTOR / PREFETCH_MOD) instructions in each
|
|
iteration. */
|
|
n_prefetches = ((unroll_factor + ref->prefetch_mod - 1)
|
|
/ ref->prefetch_mod);
|
|
prefetch_slots = n_prefetches * slots_per_prefetch;
|
|
|
|
/* If more than half of the prefetches would be lost anyway, do not
|
|
issue the prefetch. */
|
|
if (2 * remaining_prefetch_slots < prefetch_slots)
|
|
continue;
|
|
|
|
ref->issue_prefetch_p = true;
|
|
|
|
if (remaining_prefetch_slots <= prefetch_slots)
|
|
return true;
|
|
remaining_prefetch_slots -= prefetch_slots;
|
|
any = true;
|
|
}
|
|
|
|
return any;
|
|
}
|
|
|
|
/* Determine whether there is any reference suitable for prefetching
|
|
in GROUPS. */
|
|
|
|
static bool
|
|
anything_to_prefetch_p (struct mem_ref_group *groups)
|
|
{
|
|
struct mem_ref *ref;
|
|
|
|
for (; groups; groups = groups->next)
|
|
for (ref = groups->refs; ref; ref = ref->next)
|
|
if (should_issue_prefetch_p (ref))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
/* Issue prefetches for the reference REF into loop as decided before.
|
|
HEAD is the number of iterations to prefetch ahead. UNROLL_FACTOR
|
|
is the factor by which LOOP was unrolled. */
|
|
|
|
static void
|
|
issue_prefetch_ref (struct mem_ref *ref, unsigned unroll_factor, unsigned ahead)
|
|
{
|
|
HOST_WIDE_INT delta;
|
|
tree addr, addr_base, write_p, local;
|
|
gimple prefetch;
|
|
gimple_stmt_iterator bsi;
|
|
unsigned n_prefetches, ap;
|
|
bool nontemporal = ref->reuse_distance >= L2_CACHE_SIZE_BYTES;
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Issued%s prefetch for %p.\n",
|
|
nontemporal ? " nontemporal" : "",
|
|
(void *) ref);
|
|
|
|
bsi = gsi_for_stmt (ref->stmt);
|
|
|
|
n_prefetches = ((unroll_factor + ref->prefetch_mod - 1)
|
|
/ ref->prefetch_mod);
|
|
addr_base = build_fold_addr_expr_with_type (ref->mem, ptr_type_node);
|
|
addr_base = force_gimple_operand_gsi (&bsi, unshare_expr (addr_base),
|
|
true, NULL, true, GSI_SAME_STMT);
|
|
write_p = ref->write_p ? integer_one_node : integer_zero_node;
|
|
local = build_int_cst (integer_type_node, nontemporal ? 0 : 3);
|
|
|
|
for (ap = 0; ap < n_prefetches; ap++)
|
|
{
|
|
/* Determine the address to prefetch. */
|
|
delta = (ahead + ap * ref->prefetch_mod) * ref->group->step;
|
|
addr = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
|
|
addr_base, size_int (delta));
|
|
addr = force_gimple_operand_gsi (&bsi, unshare_expr (addr), true, NULL,
|
|
true, GSI_SAME_STMT);
|
|
|
|
/* Create the prefetch instruction. */
|
|
prefetch = gimple_build_call (built_in_decls[BUILT_IN_PREFETCH],
|
|
3, addr, write_p, local);
|
|
gsi_insert_before (&bsi, prefetch, GSI_SAME_STMT);
|
|
}
|
|
}
|
|
|
|
/* Issue prefetches for the references in GROUPS into loop as decided before.
|
|
HEAD is the number of iterations to prefetch ahead. UNROLL_FACTOR is the
|
|
factor by that LOOP was unrolled. */
|
|
|
|
static void
|
|
issue_prefetches (struct mem_ref_group *groups,
|
|
unsigned unroll_factor, unsigned ahead)
|
|
{
|
|
struct mem_ref *ref;
|
|
|
|
for (; groups; groups = groups->next)
|
|
for (ref = groups->refs; ref; ref = ref->next)
|
|
if (ref->issue_prefetch_p)
|
|
issue_prefetch_ref (ref, unroll_factor, ahead);
|
|
}
|
|
|
|
/* Returns true if REF is a memory write for that a nontemporal store insn
|
|
can be used. */
|
|
|
|
static bool
|
|
nontemporal_store_p (struct mem_ref *ref)
|
|
{
|
|
enum machine_mode mode;
|
|
enum insn_code code;
|
|
|
|
/* REF must be a write that is not reused. We require it to be independent
|
|
on all other memory references in the loop, as the nontemporal stores may
|
|
be reordered with respect to other memory references. */
|
|
if (!ref->write_p
|
|
|| !ref->independent_p
|
|
|| ref->reuse_distance < L2_CACHE_SIZE_BYTES)
|
|
return false;
|
|
|
|
/* Check that we have the storent instruction for the mode. */
|
|
mode = TYPE_MODE (TREE_TYPE (ref->mem));
|
|
if (mode == BLKmode)
|
|
return false;
|
|
|
|
code = optab_handler (storent_optab, mode)->insn_code;
|
|
return code != CODE_FOR_nothing;
|
|
}
|
|
|
|
/* If REF is a nontemporal store, we mark the corresponding modify statement
|
|
and return true. Otherwise, we return false. */
|
|
|
|
static bool
|
|
mark_nontemporal_store (struct mem_ref *ref)
|
|
{
|
|
if (!nontemporal_store_p (ref))
|
|
return false;
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Marked reference %p as a nontemporal store.\n",
|
|
(void *) ref);
|
|
|
|
gimple_assign_set_nontemporal_move (ref->stmt, true);
|
|
ref->storent_p = true;
|
|
|
|
return true;
|
|
}
|
|
|
|
/* Issue a memory fence instruction after LOOP. */
|
|
|
|
static void
|
|
emit_mfence_after_loop (struct loop *loop)
|
|
{
|
|
VEC (edge, heap) *exits = get_loop_exit_edges (loop);
|
|
edge exit;
|
|
gimple call;
|
|
gimple_stmt_iterator bsi;
|
|
unsigned i;
|
|
|
|
for (i = 0; VEC_iterate (edge, exits, i, exit); i++)
|
|
{
|
|
call = gimple_build_call (FENCE_FOLLOWING_MOVNT, 0);
|
|
|
|
if (!single_pred_p (exit->dest)
|
|
/* If possible, we prefer not to insert the fence on other paths
|
|
in cfg. */
|
|
&& !(exit->flags & EDGE_ABNORMAL))
|
|
split_loop_exit_edge (exit);
|
|
bsi = gsi_after_labels (exit->dest);
|
|
|
|
gsi_insert_before (&bsi, call, GSI_NEW_STMT);
|
|
mark_virtual_ops_for_renaming (call);
|
|
}
|
|
|
|
VEC_free (edge, heap, exits);
|
|
update_ssa (TODO_update_ssa_only_virtuals);
|
|
}
|
|
|
|
/* Returns true if we can use storent in loop, false otherwise. */
|
|
|
|
static bool
|
|
may_use_storent_in_loop_p (struct loop *loop)
|
|
{
|
|
bool ret = true;
|
|
|
|
if (loop->inner != NULL)
|
|
return false;
|
|
|
|
/* If we must issue a mfence insn after using storent, check that there
|
|
is a suitable place for it at each of the loop exits. */
|
|
if (FENCE_FOLLOWING_MOVNT != NULL_TREE)
|
|
{
|
|
VEC (edge, heap) *exits = get_loop_exit_edges (loop);
|
|
unsigned i;
|
|
edge exit;
|
|
|
|
for (i = 0; VEC_iterate (edge, exits, i, exit); i++)
|
|
if ((exit->flags & EDGE_ABNORMAL)
|
|
&& exit->dest == EXIT_BLOCK_PTR)
|
|
ret = false;
|
|
|
|
VEC_free (edge, heap, exits);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Marks nontemporal stores in LOOP. GROUPS contains the description of memory
|
|
references in the loop. */
|
|
|
|
static void
|
|
mark_nontemporal_stores (struct loop *loop, struct mem_ref_group *groups)
|
|
{
|
|
struct mem_ref *ref;
|
|
bool any = false;
|
|
|
|
if (!may_use_storent_in_loop_p (loop))
|
|
return;
|
|
|
|
for (; groups; groups = groups->next)
|
|
for (ref = groups->refs; ref; ref = ref->next)
|
|
any |= mark_nontemporal_store (ref);
|
|
|
|
if (any && FENCE_FOLLOWING_MOVNT != NULL_TREE)
|
|
emit_mfence_after_loop (loop);
|
|
}
|
|
|
|
/* Determines whether we can profitably unroll LOOP FACTOR times, and if
|
|
this is the case, fill in DESC by the description of number of
|
|
iterations. */
|
|
|
|
static bool
|
|
should_unroll_loop_p (struct loop *loop, struct tree_niter_desc *desc,
|
|
unsigned factor)
|
|
{
|
|
if (!can_unroll_loop_p (loop, factor, desc))
|
|
return false;
|
|
|
|
/* We only consider loops without control flow for unrolling. This is not
|
|
a hard restriction -- tree_unroll_loop works with arbitrary loops
|
|
as well; but the unrolling/prefetching is usually more profitable for
|
|
loops consisting of a single basic block, and we want to limit the
|
|
code growth. */
|
|
if (loop->num_nodes > 2)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/* Determine the coefficient by that unroll LOOP, from the information
|
|
contained in the list of memory references REFS. Description of
|
|
umber of iterations of LOOP is stored to DESC. NINSNS is the number of
|
|
insns of the LOOP. EST_NITER is the estimated number of iterations of
|
|
the loop, or -1 if no estimate is available. */
|
|
|
|
static unsigned
|
|
determine_unroll_factor (struct loop *loop, struct mem_ref_group *refs,
|
|
unsigned ninsns, struct tree_niter_desc *desc,
|
|
HOST_WIDE_INT est_niter)
|
|
{
|
|
unsigned upper_bound;
|
|
unsigned nfactor, factor, mod_constraint;
|
|
struct mem_ref_group *agp;
|
|
struct mem_ref *ref;
|
|
|
|
/* First check whether the loop is not too large to unroll. We ignore
|
|
PARAM_MAX_UNROLL_TIMES, because for small loops, it prevented us
|
|
from unrolling them enough to make exactly one cache line covered by each
|
|
iteration. Also, the goal of PARAM_MAX_UNROLL_TIMES is to prevent
|
|
us from unrolling the loops too many times in cases where we only expect
|
|
gains from better scheduling and decreasing loop overhead, which is not
|
|
the case here. */
|
|
upper_bound = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / ninsns;
|
|
|
|
/* If we unrolled the loop more times than it iterates, the unrolled version
|
|
of the loop would be never entered. */
|
|
if (est_niter >= 0 && est_niter < (HOST_WIDE_INT) upper_bound)
|
|
upper_bound = est_niter;
|
|
|
|
if (upper_bound <= 1)
|
|
return 1;
|
|
|
|
/* Choose the factor so that we may prefetch each cache just once,
|
|
but bound the unrolling by UPPER_BOUND. */
|
|
factor = 1;
|
|
for (agp = refs; agp; agp = agp->next)
|
|
for (ref = agp->refs; ref; ref = ref->next)
|
|
if (should_issue_prefetch_p (ref))
|
|
{
|
|
mod_constraint = ref->prefetch_mod;
|
|
nfactor = least_common_multiple (mod_constraint, factor);
|
|
if (nfactor <= upper_bound)
|
|
factor = nfactor;
|
|
}
|
|
|
|
if (!should_unroll_loop_p (loop, desc, factor))
|
|
return 1;
|
|
|
|
return factor;
|
|
}
|
|
|
|
/* Returns the total volume of the memory references REFS, taking into account
|
|
reuses in the innermost loop and cache line size. TODO -- we should also
|
|
take into account reuses across the iterations of the loops in the loop
|
|
nest. */
|
|
|
|
static unsigned
|
|
volume_of_references (struct mem_ref_group *refs)
|
|
{
|
|
unsigned volume = 0;
|
|
struct mem_ref_group *gr;
|
|
struct mem_ref *ref;
|
|
|
|
for (gr = refs; gr; gr = gr->next)
|
|
for (ref = gr->refs; ref; ref = ref->next)
|
|
{
|
|
/* Almost always reuses another value? */
|
|
if (ref->prefetch_before != PREFETCH_ALL)
|
|
continue;
|
|
|
|
/* If several iterations access the same cache line, use the size of
|
|
the line divided by this number. Otherwise, a cache line is
|
|
accessed in each iteration. TODO -- in the latter case, we should
|
|
take the size of the reference into account, rounding it up on cache
|
|
line size multiple. */
|
|
volume += L1_CACHE_LINE_SIZE / ref->prefetch_mod;
|
|
}
|
|
return volume;
|
|
}
|
|
|
|
/* Returns the volume of memory references accessed across VEC iterations of
|
|
loops, whose sizes are described in the LOOP_SIZES array. N is the number
|
|
of the loops in the nest (length of VEC and LOOP_SIZES vectors). */
|
|
|
|
static unsigned
|
|
volume_of_dist_vector (lambda_vector vec, unsigned *loop_sizes, unsigned n)
|
|
{
|
|
unsigned i;
|
|
|
|
for (i = 0; i < n; i++)
|
|
if (vec[i] != 0)
|
|
break;
|
|
|
|
if (i == n)
|
|
return 0;
|
|
|
|
gcc_assert (vec[i] > 0);
|
|
|
|
/* We ignore the parts of the distance vector in subloops, since usually
|
|
the numbers of iterations are much smaller. */
|
|
return loop_sizes[i] * vec[i];
|
|
}
|
|
|
|
/* Add the steps of ACCESS_FN multiplied by STRIDE to the array STRIDE
|
|
at the position corresponding to the loop of the step. N is the depth
|
|
of the considered loop nest, and, LOOP is its innermost loop. */
|
|
|
|
static void
|
|
add_subscript_strides (tree access_fn, unsigned stride,
|
|
HOST_WIDE_INT *strides, unsigned n, struct loop *loop)
|
|
{
|
|
struct loop *aloop;
|
|
tree step;
|
|
HOST_WIDE_INT astep;
|
|
unsigned min_depth = loop_depth (loop) - n;
|
|
|
|
while (TREE_CODE (access_fn) == POLYNOMIAL_CHREC)
|
|
{
|
|
aloop = get_chrec_loop (access_fn);
|
|
step = CHREC_RIGHT (access_fn);
|
|
access_fn = CHREC_LEFT (access_fn);
|
|
|
|
if ((unsigned) loop_depth (aloop) <= min_depth)
|
|
continue;
|
|
|
|
if (host_integerp (step, 0))
|
|
astep = tree_low_cst (step, 0);
|
|
else
|
|
astep = L1_CACHE_LINE_SIZE;
|
|
|
|
strides[n - 1 - loop_depth (loop) + loop_depth (aloop)] += astep * stride;
|
|
|
|
}
|
|
}
|
|
|
|
/* Returns the volume of memory references accessed between two consecutive
|
|
self-reuses of the reference DR. We consider the subscripts of DR in N
|
|
loops, and LOOP_SIZES contains the volumes of accesses in each of the
|
|
loops. LOOP is the innermost loop of the current loop nest. */
|
|
|
|
static unsigned
|
|
self_reuse_distance (data_reference_p dr, unsigned *loop_sizes, unsigned n,
|
|
struct loop *loop)
|
|
{
|
|
tree stride, access_fn;
|
|
HOST_WIDE_INT *strides, astride;
|
|
VEC (tree, heap) *access_fns;
|
|
tree ref = DR_REF (dr);
|
|
unsigned i, ret = ~0u;
|
|
|
|
/* In the following example:
|
|
|
|
for (i = 0; i < N; i++)
|
|
for (j = 0; j < N; j++)
|
|
use (a[j][i]);
|
|
the same cache line is accessed each N steps (except if the change from
|
|
i to i + 1 crosses the boundary of the cache line). Thus, for self-reuse,
|
|
we cannot rely purely on the results of the data dependence analysis.
|
|
|
|
Instead, we compute the stride of the reference in each loop, and consider
|
|
the innermost loop in that the stride is less than cache size. */
|
|
|
|
strides = XCNEWVEC (HOST_WIDE_INT, n);
|
|
access_fns = DR_ACCESS_FNS (dr);
|
|
|
|
for (i = 0; VEC_iterate (tree, access_fns, i, access_fn); i++)
|
|
{
|
|
/* Keep track of the reference corresponding to the subscript, so that we
|
|
know its stride. */
|
|
while (handled_component_p (ref) && TREE_CODE (ref) != ARRAY_REF)
|
|
ref = TREE_OPERAND (ref, 0);
|
|
|
|
if (TREE_CODE (ref) == ARRAY_REF)
|
|
{
|
|
stride = TYPE_SIZE_UNIT (TREE_TYPE (ref));
|
|
if (host_integerp (stride, 1))
|
|
astride = tree_low_cst (stride, 1);
|
|
else
|
|
astride = L1_CACHE_LINE_SIZE;
|
|
|
|
ref = TREE_OPERAND (ref, 0);
|
|
}
|
|
else
|
|
astride = 1;
|
|
|
|
add_subscript_strides (access_fn, astride, strides, n, loop);
|
|
}
|
|
|
|
for (i = n; i-- > 0; )
|
|
{
|
|
unsigned HOST_WIDE_INT s;
|
|
|
|
s = strides[i] < 0 ? -strides[i] : strides[i];
|
|
|
|
if (s < (unsigned) L1_CACHE_LINE_SIZE
|
|
&& (loop_sizes[i]
|
|
> (unsigned) (L1_CACHE_SIZE_BYTES / NONTEMPORAL_FRACTION)))
|
|
{
|
|
ret = loop_sizes[i];
|
|
break;
|
|
}
|
|
}
|
|
|
|
free (strides);
|
|
return ret;
|
|
}
|
|
|
|
/* Determines the distance till the first reuse of each reference in REFS
|
|
in the loop nest of LOOP. NO_OTHER_REFS is true if there are no other
|
|
memory references in the loop. */
|
|
|
|
static void
|
|
determine_loop_nest_reuse (struct loop *loop, struct mem_ref_group *refs,
|
|
bool no_other_refs)
|
|
{
|
|
struct loop *nest, *aloop;
|
|
VEC (data_reference_p, heap) *datarefs = NULL;
|
|
VEC (ddr_p, heap) *dependences = NULL;
|
|
struct mem_ref_group *gr;
|
|
struct mem_ref *ref, *refb;
|
|
VEC (loop_p, heap) *vloops = NULL;
|
|
unsigned *loop_data_size;
|
|
unsigned i, j, n;
|
|
unsigned volume, dist, adist;
|
|
HOST_WIDE_INT vol;
|
|
data_reference_p dr;
|
|
ddr_p dep;
|
|
|
|
if (loop->inner)
|
|
return;
|
|
|
|
/* Find the outermost loop of the loop nest of loop (we require that
|
|
there are no sibling loops inside the nest). */
|
|
nest = loop;
|
|
while (1)
|
|
{
|
|
aloop = loop_outer (nest);
|
|
|
|
if (aloop == current_loops->tree_root
|
|
|| aloop->inner->next)
|
|
break;
|
|
|
|
nest = aloop;
|
|
}
|
|
|
|
/* For each loop, determine the amount of data accessed in each iteration.
|
|
We use this to estimate whether the reference is evicted from the
|
|
cache before its reuse. */
|
|
find_loop_nest (nest, &vloops);
|
|
n = VEC_length (loop_p, vloops);
|
|
loop_data_size = XNEWVEC (unsigned, n);
|
|
volume = volume_of_references (refs);
|
|
i = n;
|
|
while (i-- != 0)
|
|
{
|
|
loop_data_size[i] = volume;
|
|
/* Bound the volume by the L2 cache size, since above this bound,
|
|
all dependence distances are equivalent. */
|
|
if (volume > L2_CACHE_SIZE_BYTES)
|
|
continue;
|
|
|
|
aloop = VEC_index (loop_p, vloops, i);
|
|
vol = estimated_loop_iterations_int (aloop, false);
|
|
if (vol < 0)
|
|
vol = expected_loop_iterations (aloop);
|
|
volume *= vol;
|
|
}
|
|
|
|
/* Prepare the references in the form suitable for data dependence
|
|
analysis. We ignore unanalyzable data references (the results
|
|
are used just as a heuristics to estimate temporality of the
|
|
references, hence we do not need to worry about correctness). */
|
|
for (gr = refs; gr; gr = gr->next)
|
|
for (ref = gr->refs; ref; ref = ref->next)
|
|
{
|
|
dr = create_data_ref (nest, ref->mem, ref->stmt, !ref->write_p);
|
|
|
|
if (dr)
|
|
{
|
|
ref->reuse_distance = volume;
|
|
dr->aux = ref;
|
|
VEC_safe_push (data_reference_p, heap, datarefs, dr);
|
|
}
|
|
else
|
|
no_other_refs = false;
|
|
}
|
|
|
|
for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
|
|
{
|
|
dist = self_reuse_distance (dr, loop_data_size, n, loop);
|
|
ref = (struct mem_ref *) dr->aux;
|
|
if (ref->reuse_distance > dist)
|
|
ref->reuse_distance = dist;
|
|
|
|
if (no_other_refs)
|
|
ref->independent_p = true;
|
|
}
|
|
|
|
compute_all_dependences (datarefs, &dependences, vloops, true);
|
|
|
|
for (i = 0; VEC_iterate (ddr_p, dependences, i, dep); i++)
|
|
{
|
|
if (DDR_ARE_DEPENDENT (dep) == chrec_known)
|
|
continue;
|
|
|
|
ref = (struct mem_ref *) DDR_A (dep)->aux;
|
|
refb = (struct mem_ref *) DDR_B (dep)->aux;
|
|
|
|
if (DDR_ARE_DEPENDENT (dep) == chrec_dont_know
|
|
|| DDR_NUM_DIST_VECTS (dep) == 0)
|
|
{
|
|
/* If the dependence cannot be analyzed, assume that there might be
|
|
a reuse. */
|
|
dist = 0;
|
|
|
|
ref->independent_p = false;
|
|
refb->independent_p = false;
|
|
}
|
|
else
|
|
{
|
|
/* The distance vectors are normalized to be always lexicographically
|
|
positive, hence we cannot tell just from them whether DDR_A comes
|
|
before DDR_B or vice versa. However, it is not important,
|
|
anyway -- if DDR_A is close to DDR_B, then it is either reused in
|
|
DDR_B (and it is not nontemporal), or it reuses the value of DDR_B
|
|
in cache (and marking it as nontemporal would not affect
|
|
anything). */
|
|
|
|
dist = volume;
|
|
for (j = 0; j < DDR_NUM_DIST_VECTS (dep); j++)
|
|
{
|
|
adist = volume_of_dist_vector (DDR_DIST_VECT (dep, j),
|
|
loop_data_size, n);
|
|
|
|
/* If this is a dependence in the innermost loop (i.e., the
|
|
distances in all superloops are zero) and it is not
|
|
the trivial self-dependence with distance zero, record that
|
|
the references are not completely independent. */
|
|
if (lambda_vector_zerop (DDR_DIST_VECT (dep, j), n - 1)
|
|
&& (ref != refb
|
|
|| DDR_DIST_VECT (dep, j)[n-1] != 0))
|
|
{
|
|
ref->independent_p = false;
|
|
refb->independent_p = false;
|
|
}
|
|
|
|
/* Ignore accesses closer than
|
|
L1_CACHE_SIZE_BYTES / NONTEMPORAL_FRACTION,
|
|
so that we use nontemporal prefetches e.g. if single memory
|
|
location is accessed several times in a single iteration of
|
|
the loop. */
|
|
if (adist < L1_CACHE_SIZE_BYTES / NONTEMPORAL_FRACTION)
|
|
continue;
|
|
|
|
if (adist < dist)
|
|
dist = adist;
|
|
}
|
|
}
|
|
|
|
if (ref->reuse_distance > dist)
|
|
ref->reuse_distance = dist;
|
|
if (refb->reuse_distance > dist)
|
|
refb->reuse_distance = dist;
|
|
}
|
|
|
|
free_dependence_relations (dependences);
|
|
free_data_refs (datarefs);
|
|
free (loop_data_size);
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "Reuse distances:\n");
|
|
for (gr = refs; gr; gr = gr->next)
|
|
for (ref = gr->refs; ref; ref = ref->next)
|
|
fprintf (dump_file, " ref %p distance %u\n",
|
|
(void *) ref, ref->reuse_distance);
|
|
}
|
|
}
|
|
|
|
/* Issue prefetch instructions for array references in LOOP. Returns
|
|
true if the LOOP was unrolled. */
|
|
|
|
static bool
|
|
loop_prefetch_arrays (struct loop *loop)
|
|
{
|
|
struct mem_ref_group *refs;
|
|
unsigned ahead, ninsns, time, unroll_factor;
|
|
HOST_WIDE_INT est_niter;
|
|
struct tree_niter_desc desc;
|
|
bool unrolled = false, no_other_refs;
|
|
|
|
if (optimize_loop_nest_for_size_p (loop))
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, " ignored (cold area)\n");
|
|
return false;
|
|
}
|
|
|
|
/* Step 1: gather the memory references. */
|
|
refs = gather_memory_references (loop, &no_other_refs);
|
|
|
|
/* Step 2: estimate the reuse effects. */
|
|
prune_by_reuse (refs);
|
|
|
|
if (!anything_to_prefetch_p (refs))
|
|
goto fail;
|
|
|
|
determine_loop_nest_reuse (loop, refs, no_other_refs);
|
|
|
|
/* Step 3: determine the ahead and unroll factor. */
|
|
|
|
/* FIXME: the time should be weighted by the probabilities of the blocks in
|
|
the loop body. */
|
|
time = tree_num_loop_insns (loop, &eni_time_weights);
|
|
ahead = (PREFETCH_LATENCY + time - 1) / time;
|
|
est_niter = estimated_loop_iterations_int (loop, false);
|
|
|
|
/* The prefetches will run for AHEAD iterations of the original loop. Unless
|
|
the loop rolls at least AHEAD times, prefetching the references does not
|
|
make sense. */
|
|
if (est_niter >= 0 && est_niter <= (HOST_WIDE_INT) ahead)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file,
|
|
"Not prefetching -- loop estimated to roll only %d times\n",
|
|
(int) est_niter);
|
|
goto fail;
|
|
}
|
|
|
|
mark_nontemporal_stores (loop, refs);
|
|
|
|
ninsns = tree_num_loop_insns (loop, &eni_size_weights);
|
|
unroll_factor = determine_unroll_factor (loop, refs, ninsns, &desc,
|
|
est_niter);
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Ahead %d, unroll factor %d\n", ahead, unroll_factor);
|
|
|
|
/* Step 4: what to prefetch? */
|
|
if (!schedule_prefetches (refs, unroll_factor, ahead))
|
|
goto fail;
|
|
|
|
/* Step 5: unroll the loop. TODO -- peeling of first and last few
|
|
iterations so that we do not issue superfluous prefetches. */
|
|
if (unroll_factor != 1)
|
|
{
|
|
tree_unroll_loop (loop, unroll_factor,
|
|
single_dom_exit (loop), &desc);
|
|
unrolled = true;
|
|
}
|
|
|
|
/* Step 6: issue the prefetches. */
|
|
issue_prefetches (refs, unroll_factor, ahead);
|
|
|
|
fail:
|
|
release_mem_refs (refs);
|
|
return unrolled;
|
|
}
|
|
|
|
/* Issue prefetch instructions for array references in loops. */
|
|
|
|
unsigned int
|
|
tree_ssa_prefetch_arrays (void)
|
|
{
|
|
loop_iterator li;
|
|
struct loop *loop;
|
|
bool unrolled = false;
|
|
int todo_flags = 0;
|
|
|
|
if (!HAVE_prefetch
|
|
/* It is possible to ask compiler for say -mtune=i486 -march=pentium4.
|
|
-mtune=i486 causes us having PREFETCH_BLOCK 0, since this is part
|
|
of processor costs and i486 does not have prefetch, but
|
|
-march=pentium4 causes HAVE_prefetch to be true. Ugh. */
|
|
|| PREFETCH_BLOCK == 0)
|
|
return 0;
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "Prefetching parameters:\n");
|
|
fprintf (dump_file, " simultaneous prefetches: %d\n",
|
|
SIMULTANEOUS_PREFETCHES);
|
|
fprintf (dump_file, " prefetch latency: %d\n", PREFETCH_LATENCY);
|
|
fprintf (dump_file, " prefetch block size: %d\n", PREFETCH_BLOCK);
|
|
fprintf (dump_file, " L1 cache size: %d lines, %d kB\n",
|
|
L1_CACHE_SIZE_BYTES / L1_CACHE_LINE_SIZE, L1_CACHE_SIZE);
|
|
fprintf (dump_file, " L1 cache line size: %d\n", L1_CACHE_LINE_SIZE);
|
|
fprintf (dump_file, " L2 cache size: %d kB\n", L2_CACHE_SIZE);
|
|
fprintf (dump_file, "\n");
|
|
}
|
|
|
|
initialize_original_copy_tables ();
|
|
|
|
if (!built_in_decls[BUILT_IN_PREFETCH])
|
|
{
|
|
tree type = build_function_type (void_type_node,
|
|
tree_cons (NULL_TREE,
|
|
const_ptr_type_node,
|
|
NULL_TREE));
|
|
tree decl = add_builtin_function ("__builtin_prefetch", type,
|
|
BUILT_IN_PREFETCH, BUILT_IN_NORMAL,
|
|
NULL, NULL_TREE);
|
|
DECL_IS_NOVOPS (decl) = true;
|
|
built_in_decls[BUILT_IN_PREFETCH] = decl;
|
|
}
|
|
|
|
/* We assume that size of cache line is a power of two, so verify this
|
|
here. */
|
|
gcc_assert ((PREFETCH_BLOCK & (PREFETCH_BLOCK - 1)) == 0);
|
|
|
|
FOR_EACH_LOOP (li, loop, LI_FROM_INNERMOST)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Processing loop %d:\n", loop->num);
|
|
|
|
unrolled |= loop_prefetch_arrays (loop);
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "\n\n");
|
|
}
|
|
|
|
if (unrolled)
|
|
{
|
|
scev_reset ();
|
|
todo_flags |= TODO_cleanup_cfg;
|
|
}
|
|
|
|
free_original_copy_tables ();
|
|
return todo_flags;
|
|
}
|