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/* Data structures and function declarations for the SSA value propagation

   engine.

   Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.

   Contributed by Diego Novillo <dnovillo@redhat.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 _TREE_SSA_PROPAGATE_H

#define _TREE_SSA_PROPAGATE_H 1

/* If SIM_P is true, statement S will be simulated again.  */

static inline void

prop_set_simulate_again (gimple s, bool visit_p)

{

  gimple_set_visited (s, visit_p);

}

/* Return true if statement T should be simulated again.  */

static inline bool

prop_simulate_again_p (gimple s)

{

  return gimple_visited_p (s);

}

/* Lattice values used for propagation purposes.  Specific instances

   of a propagation engine must return these values from the statement

   and PHI visit functions to direct the engine.  */

enum ssa_prop_result {

    /* The statement produces nothing of interest.  No edges will be

       added to the work lists.  */

    SSA_PROP_NOT_INTERESTING,

    /* The statement produces an interesting value.  The set SSA_NAMEs

       returned by SSA_PROP_VISIT_STMT should be added to

       INTERESTING_SSA_EDGES.  If the statement being visited is a

       conditional jump, SSA_PROP_VISIT_STMT should indicate which edge

       out of the basic block should be marked executable.  */

    SSA_PROP_INTERESTING,

    /* The statement produces a varying (i.e., useless) value and

       should not be simulated again.  If the statement being visited

       is a conditional jump, all the edges coming out of the block

       will be considered executable.  */

    SSA_PROP_VARYING

};

struct prop_value_d {

    /* Lattice value.  Each propagator is free to define its own

       lattice and this field is only meaningful while propagating.

       It will not be used by substitute_and_fold.  */

    unsigned lattice_val;

    /* Propagated value.  */

    tree value;

};

typedef struct prop_value_d prop_value_t;

/* Type of value ranges.  See value_range_d for a description of these

   types.  */

enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };

/* Range of values that can be associated with an SSA_NAME after VRP

   has executed.  */

struct value_range_d

{

  /* Lattice value represented by this range.  */

  enum value_range_type type;

  /* Minimum and maximum values represented by this range.  These

     values should be interpreted as follows:

        - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must

          be NULL.

        - If TYPE == VR_RANGE then MIN holds the minimum value and

          MAX holds the maximum value of the range [MIN, MAX].

        - If TYPE == ANTI_RANGE the variable is known to NOT

          take any values in the range [MIN, MAX].  */

  tree min;

  tree max;

  /* Set of SSA names whose value ranges are equivalent to this one.

     This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE.  */

  bitmap equiv;

};

typedef struct value_range_d value_range_t;

/* Call-back functions used by the value propagation engine.  */

typedef enum ssa_prop_result (*ssa_prop_visit_stmt_fn) (gimple, edge *, tree *);

typedef enum ssa_prop_result (*ssa_prop_visit_phi_fn) (gimple);

typedef bool (*ssa_prop_fold_stmt_fn) (gimple_stmt_iterator *gsi);

/* In tree-ssa-propagate.c  */

void ssa_propagate (ssa_prop_visit_stmt_fn, ssa_prop_visit_phi_fn);

bool valid_gimple_rhs_p (tree);

bool valid_gimple_call_p (tree);

void move_ssa_defining_stmt_for_defs (gimple, gimple);

bool update_call_from_tree (gimple_stmt_iterator *, tree);

bool stmt_makes_single_store (gimple);

bool substitute_and_fold (prop_value_t *, ssa_prop_fold_stmt_fn, bool);

#endif /* _TREE_SSA_PROPAGATE_H  */