1 /* Header file for SSA jump threading. 2 Copyright (C) 2013-2022 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify it under 7 the terms of the GNU General Public License as published by the Free 8 Software Foundation; either version 3, or (at your option) any later 9 version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GCC; see the file COPYING3. If not see 18 <http://www.gnu.org/licenses/>. */ 19 20 #ifndef GCC_TREE_SSA_THREADEDGE_H 21 #define GCC_TREE_SSA_THREADEDGE_H 22 23 // Class used to maintain path state in the jump threader and pass it 24 // to the jump threader simplifier. 25 26 class jt_state 27 { 28 public: ~jt_state()29 virtual ~jt_state () { } 30 virtual void push (edge); 31 virtual void pop (); 32 virtual void register_equiv (tree dest, tree src, bool update_range); 33 virtual void register_equivs_edge (edge e); 34 virtual void register_equivs_stmt (gimple *, basic_block, 35 class jt_simplifier *); 36 virtual void record_ranges_from_stmt (gimple *stmt, bool temporary); 37 void get_path (vec<basic_block> &); 38 void append_path (basic_block); 39 void dump (FILE *); 40 void debug (); 41 42 private: 43 auto_vec<basic_block> m_blocks; 44 static const basic_block BB_MARKER; 45 }; 46 47 // Statement simplifier callback for the jump threader. 48 49 class jt_simplifier 50 { 51 public: ~jt_simplifier()52 virtual ~jt_simplifier () { } 53 virtual tree simplify (gimple *, gimple *, basic_block, jt_state *) = 0; 54 }; 55 56 class hybrid_jt_state : public jt_state 57 { 58 private: register_equivs_stmt(gimple *,basic_block,jt_simplifier *)59 void register_equivs_stmt (gimple *, basic_block, jt_simplifier *) override 60 { 61 // Ranger has no need to simplify anything. 62 } 63 }; 64 65 class hybrid_jt_simplifier : public jt_simplifier 66 { 67 public: 68 hybrid_jt_simplifier (class gimple_ranger *r, class path_range_query *q); 69 tree simplify (gimple *stmt, gimple *, basic_block, jt_state *) override; 70 71 private: 72 void compute_ranges_from_state (gimple *stmt, jt_state *); 73 74 gimple_ranger *m_ranger; 75 path_range_query *m_query; 76 auto_vec<basic_block> m_path; 77 }; 78 79 // This is the high level threader. The entry point is 80 // thread_outgoing_edges(), which calculates and registers paths to be 81 // threaded. When all candidates have been registered, 82 // thread_through_all_blocks() is called to actually change the CFG. 83 84 class jump_threader 85 { 86 public: 87 jump_threader (jt_simplifier *, class jt_state *); 88 ~jump_threader (); 89 void thread_outgoing_edges (basic_block); 90 void remove_jump_threads_including (edge_def *); 91 bool thread_through_all_blocks (bool may_peel_loop_headers); 92 93 private: 94 tree simplify_control_stmt_condition (edge, gimple *); 95 tree simplify_control_stmt_condition_1 (edge, 96 gimple *, 97 tree op0, 98 tree_code cond_code, 99 tree op1, 100 unsigned limit); 101 102 bool thread_around_empty_blocks (vec<class jump_thread_edge *> *path, 103 edge, bitmap visited); 104 int thread_through_normal_block (vec<jump_thread_edge *> *path, 105 edge, bitmap visited); 106 void thread_across_edge (edge); 107 bool record_temporary_equivalences_from_phis (edge); 108 gimple *record_temporary_equivalences_from_stmts_at_dest (edge); 109 110 // Dummy condition to avoid creating lots of throw away statements. 111 gcond *dummy_cond; 112 113 class fwd_jt_path_registry *m_registry; 114 jt_simplifier *m_simplifier; 115 jt_state *m_state; 116 }; 117 118 extern void propagate_threaded_block_debug_into (basic_block, basic_block); 119 extern bool single_succ_to_potentially_threadable_block (basic_block); 120 121 // ?? All this ssa_name_values stuff is the store of values for 122 // avail_exprs_stack and const_and_copies, so it really belongs in the 123 // jump_threader class. However, it's probably not worth touching 124 // this, since all this windable state is slated to go with the 125 // ranger. 126 extern vec<tree> ssa_name_values; 127 #define SSA_NAME_VALUE(x) \ 128 (SSA_NAME_VERSION (x) < ssa_name_values.length () \ 129 ? ssa_name_values[SSA_NAME_VERSION (x)] \ 130 : NULL_TREE) 131 extern void set_ssa_name_value (tree, tree); 132 133 #endif /* GCC_TREE_SSA_THREADEDGE_H */ 134