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/* DDG - Data Dependence Graph - interface.

   Copyright (C) 2004, 2007

   Free Software Foundation, Inc.

   Contributed by Ayal Zaks and Mustafa Hagog <zaks,mustafa@il.ibm.com>

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under

the terms of the GNU General Public License as published by the Free

Software Foundation; either version 3, or (at your option) any later

version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY

WARRANTY; without even the implied warranty of MERCHANTABILITY or

FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

for more details.

You should have received a copy of the GNU General Public License

along with GCC; see the file COPYING3.  If not see

<http://www.gnu.org/licenses/>.  */

#ifndef GCC_DDG_H

#define GCC_DDG_H

/* For sbitmap.  */

#include "sbitmap.h"

/* For basic_block.  */

#include "basic-block.h"

/* For struct df.  */

#include "df.h"

typedef struct ddg_node *ddg_node_ptr;

typedef struct ddg_edge *ddg_edge_ptr;

typedef struct ddg *ddg_ptr;

typedef struct ddg_scc *ddg_scc_ptr;

typedef struct ddg_all_sccs *ddg_all_sccs_ptr;

typedef enum {TRUE_DEP, OUTPUT_DEP, ANTI_DEP} dep_type;

typedef enum {REG_OR_MEM_DEP, REG_DEP, MEM_DEP, REG_AND_MEM_DEP}

             dep_data_type;

/* The following two macros enables direct access to the successors and

   predecessors bitmaps held in each ddg_node.  Do not make changes to

   these bitmaps, unless you want to change the DDG.  */

#define NODE_SUCCESSORS(x)  ((x)->successors)

#define NODE_PREDECESSORS(x)  ((x)->predecessors)

/* A structure that represents a node in the DDG.  */

struct ddg_node

{

  /* Each node has a unique CUID index.  These indices increase monotonically

     (according to the order of the corresponding INSN in the BB), starting

     from 0 with no gaps.  */

  int cuid;

  /* The insn represented by the node.  */

  rtx insn;

  /* A note preceding INSN (or INSN itself), such that all insns linked

     from FIRST_NOTE until INSN (inclusive of both) are moved together

     when reordering the insns.  This takes care of notes that should

     continue to precede INSN.  */

  rtx first_note;

  /* Incoming and outgoing dependency edges.  */

  ddg_edge_ptr in;

  ddg_edge_ptr out;

  /* Each bit corresponds to a ddg_node according to its cuid, and is

     set iff the node is a successor/predecessor of "this" node.  */

  sbitmap successors;

  sbitmap predecessors;

  /* For general use by algorithms manipulating the ddg.  */

  union {

    int count;

    void *info;

  } aux;

};

/* A structure that represents an edge in the DDG.  */

struct ddg_edge

{

  /* The source and destination nodes of the dependency edge.  */

  ddg_node_ptr src;

  ddg_node_ptr dest;

  /* TRUE, OUTPUT or ANTI dependency.  */

  dep_type type;

  /* REG or MEM dependency.  */

  dep_data_type data_type;

  /* Latency of the dependency.  */

  int latency;

  /* The distance: number of loop iterations the dependency crosses.  */

  int distance;

  /* The following two fields are used to form a linked list of the in/out

     going edges to/from each node.  */

  ddg_edge_ptr next_in;

  ddg_edge_ptr next_out;

  /* For general use by algorithms manipulating the ddg.  */

  union {

    int count;

    void *info;

  } aux;

};

/* This structure holds the Data Dependence Graph for a basic block.  */

struct ddg

{

  /* The basic block for which this DDG is built.  */

  basic_block bb;

  /* Number of instructions in the basic block.  */

  int num_nodes;

  /* Number of load/store instructions in the BB - statistics.  */

  int num_loads;

  int num_stores;

  /* This array holds the nodes in the graph; it is indexed by the node

     cuid, which follows the order of the instructions in the BB.  */

  ddg_node_ptr nodes;

  /* The branch closing the loop.  */

  ddg_node_ptr closing_branch;

  /* Build dependence edges for closing_branch, when set.  In certain cases,

     the closing branch can be dealt with separately from the insns of the

     loop, and then no such deps are needed.  */

  int closing_branch_deps;

  /* Array and number of backarcs (edges with distance > 0) in the DDG.  */

  ddg_edge_ptr *backarcs;

  int num_backarcs;

};

/* Holds information on an SCC (Strongly Connected Component) of the DDG.  */

struct ddg_scc

{

  /* A bitmap that represents the nodes of the DDG that are in the SCC.  */

  sbitmap nodes;

  /* Array and number of backarcs (edges with distance > 0) in the SCC.  */

  ddg_edge_ptr *backarcs;

  int num_backarcs;

  /* The maximum of (total_latency/total_distance) over all cycles in SCC.  */

  int recurrence_length;

};

/* This structure holds the SCCs of the DDG.  */

struct ddg_all_sccs

{

  /* Array that holds the SCCs in the DDG, and their number.  */

  ddg_scc_ptr *sccs;

  int num_sccs;

  ddg_ptr ddg;

};

ddg_ptr create_ddg (basic_block, struct df *, int closing_branch_deps);

void free_ddg (ddg_ptr);

void print_ddg (FILE *, ddg_ptr);

void vcg_print_ddg (FILE *, ddg_ptr);

void print_ddg_edge (FILE *, ddg_edge_ptr);

ddg_node_ptr get_node_of_insn (ddg_ptr, rtx);

void find_successors (sbitmap result, ddg_ptr, sbitmap);

void find_predecessors (sbitmap result, ddg_ptr, sbitmap);

ddg_all_sccs_ptr create_ddg_all_sccs (ddg_ptr);

void free_ddg_all_sccs (ddg_all_sccs_ptr);

int find_nodes_on_paths (sbitmap result, ddg_ptr, sbitmap from, sbitmap to);

int longest_simple_path (ddg_ptr, int from, int to, sbitmap via);

#endif /* GCC_DDG_H */