gcc/ddg.h

   1 /* DDG - Data Dependence Graph - interface.
   2    Copyright (C) 2004-2023 Free Software Foundation, Inc.
   3    Contributed by Ayal Zaks and Mustafa Hagog <zaks,mustafa@il.ibm.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GCC_DDG_H
  22 #define GCC_DDG_H
  23
  24 /* For sbitmap.  */
  25
  26 typedef struct ddg_node *ddg_node_ptr;
  27 typedef struct ddg_edge *ddg_edge_ptr;
  28 typedef struct ddg *ddg_ptr;
  29 typedef struct ddg_scc *ddg_scc_ptr;
  30 typedef struct ddg_all_sccs *ddg_all_sccs_ptr;
  31
  32 enum dep_type {TRUE_DEP, OUTPUT_DEP, ANTI_DEP};
  33 enum dep_data_type {REG_OR_MEM_DEP, REG_DEP, MEM_DEP, REG_AND_MEM_DEP};
  34
  35 /* The following two macros enables direct access to the successors and
  36    predecessors bitmaps held in each ddg_node.  Do not make changes to
  37    these bitmaps, unless you want to change the DDG.  */
  38 #define NODE_SUCCESSORS(x)  ((x)->successors)
  39 #define NODE_PREDECESSORS(x)  ((x)->predecessors)
  40
  41 /* A structure that represents a node in the DDG.  */
  42 struct ddg_node
  43 {
  44   /* Each node has a unique CUID index.  These indices increase monotonically
  45      (according to the order of the corresponding INSN in the BB), starting
  46      from 0 with no gaps.  */
  47   int cuid;
  48
  49   /* The insn represented by the node.  */
  50   rtx_insn *insn;
  51
  52   /* A note preceding INSN (or INSN itself), such that all insns linked
  53      from FIRST_NOTE until INSN (inclusive of both) are moved together
  54      when reordering the insns.  This takes care of notes that should
  55      continue to precede INSN.  */
  56   rtx_insn *first_note;
  57
  58   /* Incoming and outgoing dependency edges.  */
  59   ddg_edge_ptr in;
  60   ddg_edge_ptr out;
  61
  62   /* Each bit corresponds to a ddg_node according to its cuid, and is
  63      set iff the node is a successor/predecessor of "this" node.  */
  64   sbitmap successors;
  65   sbitmap predecessors;
  66
  67   /* Temporary array used for Floyd-Warshall algorithm to find
  68      scc recurrence length.  */
  69   int *max_dist;
  70
  71   /* For general use by algorithms manipulating the ddg.  */
  72   union {
  73     int count;
  74     void *info;
  75   } aux;
  76 };
  77
  78 /* A structure that represents an edge in the DDG.  */
  79 struct ddg_edge
  80 {
  81   /* The source and destination nodes of the dependency edge.  */
  82   ddg_node_ptr src;
  83   ddg_node_ptr dest;
  84
  85   /* TRUE, OUTPUT or ANTI dependency.  */
  86   dep_type type;
  87
  88   /* REG or MEM dependency.  */
  89   dep_data_type data_type;
  90
  91   /* Latency of the dependency.  */
  92   int latency;
  93
  94   /* The distance: number of loop iterations the dependency crosses.  */
  95   int distance;
  96
  97   /* The following two fields are used to form a linked list of the in/out
  98      going edges to/from each node.  */
  99   ddg_edge_ptr next_in;
 100   ddg_edge_ptr next_out;
 101
 102   /* Is true when edge is already in scc.  */
 103   bool in_scc;
 104 };
 105
 106 /* This structure holds the Data Dependence Graph for a basic block.  */
 107 struct ddg
 108 {
 109   /* The basic block for which this DDG is built.  */
 110   basic_block bb;
 111
 112   /* Number of instructions in the basic block.  */
 113   int num_nodes;
 114
 115   /* Number of load/store instructions in the BB - statistics.  */
 116   int num_loads;
 117   int num_stores;
 118
 119   /* This array holds the nodes in the graph; it is indexed by the node
 120      cuid, which follows the order of the instructions in the BB.  */
 121   ddg_node_ptr nodes;
 122
 123   /* The branch closing the loop.  */
 124   ddg_node_ptr closing_branch;
 125
 126   /* Build dependence edges for closing_branch, when set.  In certain cases,
 127      the closing branch can be dealt with separately from the insns of the
 128      loop, and then no such deps are needed.  */
 129   int closing_branch_deps;
 130
 131   /* Array and number of backarcs (edges with distance > 0) in the DDG.  */
 132   int num_backarcs;
 133   ddg_edge_ptr *backarcs;
 134 };
 135
 136 \f
 137 /* Holds information on an SCC (Strongly Connected Component) of the DDG.  */
 138 struct ddg_scc
 139 {
 140   /* A bitmap that represents the nodes of the DDG that are in the SCC.  */
 141   sbitmap nodes;
 142
 143   /* Array and number of backarcs (edges with distance > 0) in the SCC.  */
 144   ddg_edge_ptr *backarcs;
 145   int num_backarcs;
 146
 147   /* The maximum of (total_latency/total_distance) over all cycles in SCC.  */
 148   int recurrence_length;
 149 };
 150
 151 /* This structure holds the SCCs of the DDG.  */
 152 struct ddg_all_sccs
 153 {
 154   /* Array that holds the SCCs in the DDG, and their number.  */
 155   ddg_scc_ptr *sccs;
 156   int num_sccs;
 157
 158   ddg_ptr ddg;
 159 };
 160
 161 \f
 162 ddg_ptr create_ddg (basic_block, int closing_branch_deps);
 163 void free_ddg (ddg_ptr);
 164
 165 void print_ddg (FILE *, ddg_ptr);
 166 void vcg_print_ddg (FILE *, ddg_ptr);
 167 void print_ddg_edge (FILE *, ddg_edge_ptr);
 168 void print_sccs (FILE *, ddg_all_sccs_ptr, ddg_ptr);
 169
 170 ddg_node_ptr get_node_of_insn (ddg_ptr, rtx_insn *);
 171
 172 void find_successors (sbitmap result, ddg_ptr, sbitmap);
 173 void find_predecessors (sbitmap result, ddg_ptr, sbitmap);
 174
 175 ddg_all_sccs_ptr create_ddg_all_sccs (ddg_ptr);
 176 void free_ddg_all_sccs (ddg_all_sccs_ptr);
 177
 178 int find_nodes_on_paths (sbitmap result, ddg_ptr, sbitmap from, sbitmap to);
 179
 180 bool autoinc_var_is_used_p (rtx_insn *, rtx_insn *);
 181
 182 #endif /* GCC_DDG_H */