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.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@145494 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 99 insertions, 407 deletions

diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c
index a340c5e2103..315b5507b71 100644
--- a/gcc/tree-ssa-dse.c
+++ b/gcc/tree-ssa-dse.c
@@ -84,13 +84,6 @@ struct dse_block_local_data
   bitmap stores;
 };
 
-/* Basic blocks of the potentially dead store and the following
-   store, for memory_address_same.  */
-struct address_walk_data
-{
-  basic_block store1_bb, store2_bb;
-};
-
 static bool gate_dse (void);
 static unsigned int tree_ssa_dse (void);
 static void dse_initialize_block_local_data (struct dom_walk_data *,
@@ -151,218 +144,112 @@ dse_initialize_block_local_data (struct dom_walk_data *walk_data,
     }
 }
 
-/* Helper function for memory_address_same via walk_tree.  Returns
-   non-NULL if it finds an SSA_NAME which is part of the address,
-   such that the definition of the SSA_NAME post-dominates the store
-   we want to delete but not the store that we believe makes it
-   redundant.  This indicates that the address may change between
-   the two stores.  */
-
-static tree
-memory_ssa_name_same (tree *expr_p, int *walk_subtrees ATTRIBUTE_UNUSED,
-		      void *data)
-{
-  struct address_walk_data *walk_data = (struct address_walk_data *) data;
-  tree expr = *expr_p;
-  gimple def_stmt;
-  basic_block def_bb;
-
-  if (TREE_CODE (expr) != SSA_NAME)
-    return NULL_TREE;
-
-  /* If we've found a default definition, then there's no problem.  Both
-     stores will post-dominate it.  And def_bb will be NULL.  */
-  if (SSA_NAME_IS_DEFAULT_DEF (expr))
-    return NULL_TREE;
-
-  def_stmt = SSA_NAME_DEF_STMT (expr);
-  def_bb = gimple_bb (def_stmt);
-
-  /* DEF_STMT must dominate both stores.  So if it is in the same
-     basic block as one, it does not post-dominate that store.  */
-  if (walk_data->store1_bb != def_bb
-      && dominated_by_p (CDI_POST_DOMINATORS, walk_data->store1_bb, def_bb))
-    {
-      if (walk_data->store2_bb == def_bb
-	  || !dominated_by_p (CDI_POST_DOMINATORS, walk_data->store2_bb,
-			      def_bb))
-	/* Return non-NULL to stop the walk.  */
-	return *expr_p;
-    }
-
-  return NULL_TREE;
-}
-
-/* Return TRUE if the destination memory address in STORE1 and STORE2
-   might be modified after STORE1, before control reaches STORE2.  */
-
-static bool
-memory_address_same (gimple store1, gimple store2)
-{
-  struct address_walk_data walk_data;
-
-  walk_data.store1_bb = gimple_bb (store1);
-  walk_data.store2_bb = gimple_bb (store2);
-
-  return (walk_tree (gimple_assign_lhs_ptr (store1), memory_ssa_name_same,
-		     &walk_data, NULL)
-	  == NULL);
-}
-
-/* Return true if there is a stmt that kills the lhs of STMT and is in the
-   virtual def-use chain of STMT without a use in between the kill and STMT.
-   Returns false if no such stmt is found.
-   *FIRST_USE_P is set to the first use of the single virtual def of
-   STMT.  *USE_P is set to the vop killed by *USE_STMT.  */
-
-static bool
-get_kill_of_stmt_lhs (gimple stmt,
-		      use_operand_p * first_use_p,
- 		      use_operand_p * use_p, gimple * use_stmt)
-{
-  tree lhs;
-
-  gcc_assert (is_gimple_assign (stmt));
-
-  lhs = gimple_assign_lhs (stmt);
-
-  /* We now walk the chain of single uses of the single VDEFs.
-     We succeeded finding a kill if the lhs of the use stmt is
-     equal to the original lhs.  We can keep walking to the next
-     use if there are no possible uses of the original lhs in
-     the stmt.  */
-  do
-    {
-      tree use_lhs;
-      def_operand_p def_p;
-
-      /* The stmt must have a single VDEF.  */
-      def_p = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_VDEF);
-      if (def_p == NULL_DEF_OPERAND_P)
-	return false;
-
-      /* Get the single immediate use of the def.  */
-      if (!single_imm_use (DEF_FROM_PTR (def_p), first_use_p, &stmt))
-	return false;
-      first_use_p = use_p;
-
-      /* If there are possible hidden uses, give up.  */
-      if (!gimple_assign_single_p (stmt)
-	  || (TREE_CODE (gimple_assign_rhs1 (stmt)) != SSA_NAME
-	      && !is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
-	return false;
-
-      /* If the use stmts lhs matches the original lhs we have
-	 found the kill, otherwise continue walking.  */
-      use_lhs = gimple_assign_lhs (stmt);
-      if (operand_equal_p (use_lhs, lhs, 0))
-	{
-	  *use_stmt = stmt;
-	  return true;
-	}
-    }
-  while (1);
-}
-
 /* A helper of dse_optimize_stmt.
-   Given a GIMPLE_ASSIGN in STMT, check that each VDEF has one
-   use, and that one use is another VDEF clobbering the first one.
-
+   Given a GIMPLE_ASSIGN in STMT, find a candidate statement *USE_STMT that
+   may prove STMT to be dead.
    Return TRUE if the above conditions are met, otherwise FALSE.  */
 
 static bool
-dse_possible_dead_store_p (gimple stmt,
-			   use_operand_p *first_use_p,
-			   use_operand_p *use_p,
-			   gimple *use_stmt,
-			   struct dse_global_data *dse_gd,
-			   struct dse_block_local_data *bd)
+dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
 {
-  ssa_op_iter op_iter;
-  bool fail = false;
-  def_operand_p var1;
-  vuse_vec_p vv;
-  tree defvar = NULL_TREE;
-  tree prev_defvar = NULL_TREE;
   gimple temp;
+  unsigned cnt = 0;
 
-  /* We want to verify that each virtual definition in STMT has
-     precisely one use and that all the virtual definitions are
-     used by the same single statement.  When complete, we
-     want USE_STMT to refer to the one statement which uses
-     all of the virtual definitions from STMT.  */
   *use_stmt = NULL;
-  FOR_EACH_SSA_VDEF_OPERAND (var1, vv, stmt, op_iter)
-    {
-      defvar = DEF_FROM_PTR (var1);
-
-      /* If this virtual def does not have precisely one use, then
-	 we will not be able to eliminate STMT.  */
-      if (!has_single_use (defvar))
-	{
-	  fail = true;
-	  break;
-	}
 
-      /* Get the one and only immediate use of DEFVAR.  */
-      single_imm_use (defvar, use_p, &temp);
-      gcc_assert (*use_p != NULL_USE_OPERAND_P);
-      *first_use_p = *use_p;
+  /* Find the first dominated statement that clobbers (part of) the
+     memory stmt stores to with no intermediate statement that may use
+     part of the memory stmt stores.  That is, find a store that may
+     prove stmt to be a dead store.  */
+  temp = stmt;
+  do
+    {
+      gimple prev, use_stmt;
+      imm_use_iterator ui;
+      bool fail = false;
+      tree defvar;
+
+      /* Limit stmt walking to be linear in the number of possibly
+         dead stores.  */
+      if (++cnt > 256)
+	return false;
 
-      /* ???  If we hit a GIMPLE_PHI we could skip to the PHI_RESULT uses.
-	 Don't bother to do that for now.  */
       if (gimple_code (temp) == GIMPLE_PHI)
+	defvar = PHI_RESULT (temp);
+      else
+	defvar = gimple_vdef (temp);
+      prev = temp;
+      temp = NULL;
+      FOR_EACH_IMM_USE_STMT (use_stmt, ui, defvar)
 	{
-	  fail = true;
-	  break;
-	}
-
-      /* In the case of memory partitions, we may get:
+	  cnt++;
 
-	   # MPT.764_162 = VDEF <MPT.764_161(D)>
-	   x = {};
-	   # MPT.764_167 = VDEF <MPT.764_162>
-	   y = {};
-
-	   So we must make sure we're talking about the same LHS.
-      */
-      if (is_gimple_assign (temp))
-	{
-	  tree base1 = get_base_address (gimple_assign_lhs (stmt));
-	  tree base2 = get_base_address (gimple_assign_lhs (temp));
-
-	  while (base1 && INDIRECT_REF_P (base1))
-	    base1 = TREE_OPERAND (base1, 0);
-	  while (base2 && INDIRECT_REF_P (base2))
-	    base2 = TREE_OPERAND (base2, 0);
-
-	  if (base1 != base2)
+	  /* In simple cases we can look through PHI nodes, but we
+	     have to be careful with loops and with memory references
+	     containing operands that are also operands of PHI nodes.
+	     See gcc.c-torture/execute/20051110-*.c.  */
+	  if (gimple_code (use_stmt) == GIMPLE_PHI)
+	    {
+	      if (temp
+		  /* We can look through PHIs to post-dominated regions
+		     without worrying if the use not also dominates prev
+		     (in which case it would be a loop PHI with the use
+		     in a latch block).  */
+		  || gimple_bb (prev) == gimple_bb (use_stmt)
+		  || !dominated_by_p (CDI_POST_DOMINATORS,
+				      gimple_bb (prev), gimple_bb (use_stmt))
+		  || dominated_by_p (CDI_DOMINATORS,
+				     gimple_bb (prev), gimple_bb (use_stmt)))
+		{
+		  fail = true;
+		  BREAK_FROM_IMM_USE_STMT (ui);
+		}
+	      temp = use_stmt;
+	    }
+	  /* If the statement is a use the store is not dead.  */
+	  else if (ref_maybe_used_by_stmt_p (use_stmt,
+					     gimple_assign_lhs (stmt)))
 	    {
 	      fail = true;
-	      break;
+	      BREAK_FROM_IMM_USE_STMT (ui);
+	    }
+	  /* If this is a store, remember it or bail out if we have
+	     multiple ones (the will be in different CFG parts then).  */
+	  else if (gimple_vdef (use_stmt))
+	    {
+	      if (temp)
+		{
+		  fail = true;
+		  BREAK_FROM_IMM_USE_STMT (ui);
+		}
+	      temp = use_stmt;
 	    }
 	}
 
-      /* If the immediate use of DEF_VAR is not the same as the
-	 previously find immediate uses, then we will not be able
-	 to eliminate STMT.  */
-      if (*use_stmt == NULL)
-	{
-	  *use_stmt = temp;
-	  prev_defvar = defvar;
-	}
-      else if (temp != *use_stmt)
+      if (fail)
+	return false;
+
+      /* If we didn't find any definition this means the store is dead
+         if it isn't a store to global reachable memory.  In this case
+	 just pretend the stmt makes itself dead.  Otherwise fail.  */
+      if (!temp)
 	{
-	  fail = true;
+	  if (is_hidden_global_store (stmt))
+	    return false;
+
+	  temp = stmt;
 	  break;
 	}
     }
+  /* We deliberately stop on clobbering statements and not only on
+     killing ones to make walking cheaper.  Otherwise we can just
+     continue walking until both stores have equal reference trees.  */
+  while (!stmt_may_clobber_ref_p (temp, gimple_assign_lhs (stmt)));
 
-  if (fail)
-    {
-      record_voperand_set (dse_gd->stores, &bd->stores, gimple_uid (stmt));
-      return false;
-    }
+  if (!is_gimple_assign (temp))
+    return false;
+
+  *use_stmt = temp;
 
   return true;
 }
@@ -393,7 +280,7 @@ dse_optimize_stmt (struct dom_walk_data *walk_data,
 
   /* If this statement has no virtual defs, then there is nothing
      to do.  */
-  if (ZERO_SSA_OPERANDS (stmt, SSA_OP_VDEF))
+  if (!gimple_vdef (stmt))
     return;
 
   /* We know we have virtual definitions.  If this is a GIMPLE_ASSIGN
@@ -406,51 +293,21 @@ dse_optimize_stmt (struct dom_walk_data *walk_data,
 
   if (is_gimple_assign (stmt))
     {
-      use_operand_p first_use_p = NULL_USE_OPERAND_P;
-      use_operand_p use_p = NULL;
       gimple use_stmt;
 
-      if (!dse_possible_dead_store_p (stmt, &first_use_p, &use_p, &use_stmt, 
-				      dse_gd, bd))
-	return;
+      record_voperand_set (dse_gd->stores, &bd->stores, gimple_uid (stmt));
 
-      /* If we have precisely one immediate use at this point, then we may
-	 have found redundant store.  Make sure that the stores are to
-	 the same memory location.  This includes checking that any
-	 SSA-form variables in the address will have the same values.  */
-      if (use_p != NULL_USE_OPERAND_P
-          && bitmap_bit_p (dse_gd->stores, get_stmt_uid (use_stmt))
-          && !operand_equal_p (gimple_assign_lhs (stmt),
-                               gimple_assign_lhs (use_stmt), 0)
-          && memory_address_same (stmt, use_stmt))
-        {
-          /* If we have precisely one immediate use at this point, but
-             the stores are not to the same memory location then walk the
-             virtual def-use chain to get the stmt which stores to that same
-             memory location.  */
-          if (!get_kill_of_stmt_lhs (stmt, &first_use_p, &use_p, &use_stmt))
-            {
-              record_voperand_set (dse_gd->stores, &bd->stores, 
-				   gimple_uid (stmt));
-              return;
-            }
-        }
+      if (!dse_possible_dead_store_p (stmt, &use_stmt))
+	return;
 
       /* If we have precisely one immediate use at this point and the
 	 stores are to the same memory location or there is a chain of
 	 virtual uses from stmt and the stmt which stores to that same
 	 memory location, then we may have found redundant store.  */
-      if (use_p != NULL_USE_OPERAND_P
-	  && bitmap_bit_p (dse_gd->stores, get_stmt_uid (use_stmt))
+      if (bitmap_bit_p (dse_gd->stores, get_stmt_uid (use_stmt))
 	  && operand_equal_p (gimple_assign_lhs (stmt),
-			      gimple_assign_lhs (use_stmt), 0)
-	  && memory_address_same (stmt, use_stmt))
+			      gimple_assign_lhs (use_stmt), 0))
 	{
-	  ssa_op_iter op_iter;
-	  def_operand_p var1;
-	  vuse_vec_p vv;
-	  tree stmt_lhs;
-
 	  /* If use_stmt is or might be a nop assignment, e.g. for
 	     struct { ... } S a, b, *p; ...
 	     b = a; b = b;
@@ -462,14 +319,14 @@ dse_optimize_stmt (struct dom_walk_data *walk_data,
 	     *p = *u; *p = *v; where p might be v, then USE_STMT
 	     acts as a use as well as definition, so store in STMT
 	     is not dead.  */
-	  if (gimple_loaded_syms (use_stmt)
-	      && bitmap_intersect_p (gimple_loaded_syms (use_stmt),
-				     gimple_stored_syms (use_stmt)))
-	    {
-              record_voperand_set (dse_gd->stores, &bd->stores, 
-				   gimple_uid (stmt));
-	      return;
-	    }
+	  if (stmt != use_stmt
+	      && !is_gimple_reg (gimple_assign_rhs1 (use_stmt))
+	      && !is_gimple_min_invariant (gimple_assign_rhs1 (use_stmt))
+	      /* ???  Should {} be invariant?  */
+	      && gimple_assign_rhs_code (use_stmt) != CONSTRUCTOR
+	      && refs_may_alias_p (gimple_assign_lhs (use_stmt),
+				   gimple_assign_rhs1 (use_stmt)))
+	    return;
 
 	  if (dump_file && (dump_flags & TDF_DETAILS))
             {
@@ -479,21 +336,7 @@ dse_optimize_stmt (struct dom_walk_data *walk_data,
             }
 
 	  /* Then we need to fix the operand of the consuming stmt.  */
-	  stmt_lhs = USE_FROM_PTR (first_use_p);
-	  FOR_EACH_SSA_VDEF_OPERAND (var1, vv, stmt, op_iter)
-	    {
-	      tree usevar;
-	      gimple temp;
-
-	      single_imm_use (DEF_FROM_PTR (var1), &use_p, &temp);
-	      gcc_assert (VUSE_VECT_NUM_ELEM (*vv) == 1);
-	      usevar = VUSE_ELEMENT_VAR (*vv, 0);
-	      SET_USE (use_p, usevar);
-
-	      /* Make sure we propagate the ABNORMAL bit setting.  */
-	      if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (stmt_lhs))
-		SSA_NAME_OCCURS_IN_ABNORMAL_PHI (usevar) = 1;
-	    }
+	  unlink_stmt_vdef (stmt);
 
 	  /* Remove the dead store.  */
 	  gsi_remove (&gsi, true);
@@ -502,8 +345,6 @@ dse_optimize_stmt (struct dom_walk_data *walk_data,
 	     SSA_NAME manager.  */
 	  release_defs (stmt);
 	}
-
-      record_voperand_set (dse_gd->stores, &bd->stores, gimple_uid (stmt));
     }
 }
 
@@ -564,6 +405,7 @@ tree_ssa_dse (void)
      this pass could be seen as an extension of DCE which needs post
      dominators.  */
   calculate_dominance_info (CDI_POST_DOMINATORS);
+  calculate_dominance_info (CDI_DOMINATORS);
 
   /* Dead store elimination is fundamentally a walk of the post-dominator
      tree and a backwards walk of statements within each block.  */
@@ -630,153 +472,3 @@ struct gimple_opt_pass pass_dse =
  }
 };
 
-/* A very simple dead store pass eliminating write only local variables.
-   The pass does not require alias information and thus can be run before
-   inlining to quickly eliminate artifacts of some common C++ constructs.  */
-
-static unsigned int
-execute_simple_dse (void)
-{
-  gimple_stmt_iterator gsi;
-  basic_block bb;
-  bitmap variables_loaded = BITMAP_ALLOC (NULL);
-  unsigned int todo = 0;
-
-  /* Collect into VARIABLES LOADED all variables that are read in function
-     body.  */
-  FOR_EACH_BB (bb)
-    for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
-
-      if (gimple_loaded_syms (gsi_stmt (gsi)))
-	bitmap_ior_into (variables_loaded,
-			 gimple_loaded_syms (gsi_stmt (gsi)));
-
-  /* Look for statements writing into the write only variables.
-     And try to remove them.  */
-
-  FOR_EACH_BB (bb)
-    for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
-      {
-	gimple stmt = gsi_stmt (gsi);
-        tree op;
-	bool removed = false;
-        ssa_op_iter iter;
-	tree size;
-
-	if (is_gimple_assign (stmt)
-	    && AGGREGATE_TYPE_P (TREE_TYPE (gimple_assign_lhs (stmt)))
-	    && (size = lang_hooks.expr_size (gimple_assign_lhs (stmt)))
-	    && integer_zerop (size))
-	  {
-	    if (dump_file && (dump_flags & TDF_DETAILS))
-	      {
-		fprintf (dump_file, "  Deleted zero-sized store '");
-		print_gimple_stmt (dump_file, stmt, 0, dump_flags);
-		fprintf (dump_file, "'\n");
-	      }
-	    removed = true;
-	    gsi_remove (&gsi, true);
-	    todo |= TODO_cleanup_cfg;
-	  }
-	else if (gimple_stored_syms (stmt)
-		 && !bitmap_empty_p (gimple_stored_syms (stmt))
-		 && (is_gimple_assign (stmt)
-		     || (is_gimple_call (stmt)
-			 && gimple_call_lhs (stmt)))
-		 && !bitmap_intersect_p (gimple_stored_syms (stmt),
-					 variables_loaded))
-	  {
-	    unsigned int i;
-	    bitmap_iterator bi;
-	    bool dead = true;
-
-	    /* See if STMT only stores to write-only variables and
-	       verify that there are no volatile operands.  tree-ssa-operands
-	       sets has_volatile_ops flag for all statements involving
-	       reads and writes when aliases are not built to prevent passes
-	       from removing them as dead.  The flag thus has no use for us
-	       and we need to look into all operands.  */
-	      
-	    EXECUTE_IF_SET_IN_BITMAP (gimple_stored_syms (stmt), 0, i, bi)
-	      {
-		tree var = referenced_var_lookup (i);
-		if (TREE_ADDRESSABLE (var)
-		    || is_global_var (var)
-		    || TREE_THIS_VOLATILE (var))
-		  dead = false;
-	      }
-
-	    if (dead && gimple_loaded_syms (stmt))
-	      EXECUTE_IF_SET_IN_BITMAP (gimple_loaded_syms (stmt), 0, i, bi)
-		if (TREE_THIS_VOLATILE (referenced_var_lookup (i)))
-		  dead = false;
-
-	    if (dead)
-	      FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_ALL_OPERANDS)
-		if (TREE_THIS_VOLATILE (op))
-		  dead = false;
-
-	    /* Look for possible occurrence var = indirect_ref (...) where
-	       indirect_ref itself is volatile.  */
-
-	    if (dead && is_gimple_assign (stmt)
-	        && TREE_THIS_VOLATILE (gimple_assign_rhs1 (stmt)))
-	      dead = false;
-
-	    if (dead)
-	      {
-		/* When LHS of var = call (); is dead, simplify it into
-		   call (); saving one operand.  */
-                if (is_gimple_call (stmt)
-                    && gimple_has_side_effects (stmt))
-		  {
-		    if (dump_file && (dump_flags & TDF_DETAILS))
-		      {
-			fprintf (dump_file, "Deleted LHS of call: ");
-			print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
-			fprintf (dump_file, "\n");
-		      }
-		    push_stmt_changes (gsi_stmt_ptr (&gsi));
-                    gimple_call_set_lhs (stmt, NULL);
-		    pop_stmt_changes (gsi_stmt_ptr (&gsi));
-		  }
-		else
-		  {
-		    if (dump_file && (dump_flags & TDF_DETAILS))
-		      {
-			fprintf (dump_file, "  Deleted dead store '");
-			print_gimple_stmt (dump_file, stmt, 0, dump_flags);
-			fprintf (dump_file, "'\n");
-		      }
-		    removed = true;
-		    gsi_remove (&gsi, true);
-		    todo |= TODO_cleanup_cfg;
-		  }
-		todo |= TODO_remove_unused_locals | TODO_ggc_collect;
-	      }
-	  }
-	if (!removed)
-	  gsi_next (&gsi);
-      }
-  BITMAP_FREE (variables_loaded);
-  return todo;
-}
-
-struct gimple_opt_pass pass_simple_dse =
-{
- {
-  GIMPLE_PASS,
-  "sdse",				/* name */
-  NULL,					/* gate */
-  execute_simple_dse,			/* execute */
-  NULL,					/* sub */
-  NULL,					/* next */
-  0,					/* static_pass_number */
-  0,					/* tv_id */
-  PROP_ssa,				/* properties_required */
-  0,					/* properties_provided */
-  0,					/* properties_destroyed */
-  0,					/* todo_flags_start */
-  TODO_dump_func          	        /* todo_flags_finish */
- }
-};