gcc/tree-ssa-threadedge.h

   1 /* Header file for SSA jump threading.
   2    Copyright (C) 2013-2021 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 // This is the high level threader.  The entry point is
  24 // thread_outgoing_edges(), which calculates and registers paths to be
  25 // threaded.  When all candidates have been registered,
  26 // thread_through_all_blocks() is called to actually change the CFG.
  27
  28 class jump_threader
  29 {
  30 public:
  31   jump_threader (class const_and_copies *,
  32                  avail_exprs_stack *,
  33                  class jump_threader_simplifier *,
  34                  class evrp_range_analyzer * = NULL);
  35   ~jump_threader ();
  36   void thread_outgoing_edges (basic_block);
  37   void remove_jump_threads_including (edge_def *);
  38   bool thread_through_all_blocks (bool may_peel_loop_headers);
  39
  40 private:
  41   tree simplify_control_stmt_condition (edge, gimple *);
  42   tree simplify_control_stmt_condition_1 (edge,
  43                                           gimple *,
  44                                           tree op0,
  45                                           tree_code cond_code,
  46                                           tree op1,
  47                                           unsigned limit);
  48
  49   bool thread_around_empty_blocks (vec<class jump_thread_edge *> *path,
  50                                    edge, bitmap visited);
  51   int thread_through_normal_block (vec<jump_thread_edge *> *path,
  52                                    edge, bitmap visited);
  53   void thread_across_edge (edge);
  54   bool record_temporary_equivalences_from_phis (edge);
  55   gimple *record_temporary_equivalences_from_stmts_at_dest (edge);
  56
  57   // Dummy condition to avoid creating lots of throw away statements.
  58   gcond *dummy_cond;
  59
  60   const_and_copies *m_const_and_copies;
  61   avail_exprs_stack *m_avail_exprs_stack;
  62   class jump_thread_path_registry *m_registry;
  63   jump_threader_simplifier *m_simplifier;
  64   evrp_range_analyzer *m_evrp_range_analyzer;
  65 };
  66
  67 // Statement simplifier callback for the jump threader.
  68
  69 class jump_threader_simplifier
  70 {
  71 public:
  72   jump_threader_simplifier (class vr_values *v,
  73                             avail_exprs_stack *avails)
  74     : m_vr_values (v),
  75       m_avail_exprs_stack (avails)
  76   { }
  77   virtual ~jump_threader_simplifier () { }
  78   virtual tree simplify (gimple *, gimple *, basic_block);
  79
  80 protected:
  81   vr_values *m_vr_values;
  82   avail_exprs_stack *m_avail_exprs_stack;
  83 };
  84
  85 extern void propagate_threaded_block_debug_into (basic_block, basic_block);
  86
  87 // ?? All this ssa_name_values stuff is the store of values for
  88 // avail_exprs_stack and const_and_copies, so it really belongs in the
  89 // jump_threader class.  However, it's probably not worth touching
  90 // this, since all this windable state is slated to go with the
  91 // ranger.
  92 extern vec<tree> ssa_name_values;
  93 #define SSA_NAME_VALUE(x) \
  94     (SSA_NAME_VERSION (x) < ssa_name_values.length () \
  95      ? ssa_name_values[SSA_NAME_VERSION (x)] \
  96      : NULL_TREE)
  97 extern void set_ssa_name_value (tree, tree);
  98
  99 #endif /* GCC_TREE_SSA_THREADEDGE_H */