gcc/tree-ssa-propagate.h

   1 /* Data structures and function declarations for the SSA value propagation
   2    engine.
   3    Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
   4    Contributed by Diego Novillo <dnovillo@redhat.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #ifndef _TREE_SSA_PROPAGATE_H
  23 #define _TREE_SSA_PROPAGATE_H 1
  24
  25 /* If SIM_P is true, statement S will be simulated again.  */
  26
  27 static inline void
  28 prop_set_simulate_again (gimple s, bool visit_p)
  29 {
  30   gimple_set_visited (s, visit_p);
  31 }
  32
  33 /* Return true if statement T should be simulated again.  */
  34
  35 static inline bool
  36 prop_simulate_again_p (gimple s)
  37 {
  38   return gimple_visited_p (s);
  39 }
  40
  41 /* Lattice values used for propagation purposes.  Specific instances
  42    of a propagation engine must return these values from the statement
  43    and PHI visit functions to direct the engine.  */
  44 enum ssa_prop_result {
  45     /* The statement produces nothing of interest.  No edges will be
  46        added to the work lists.  */
  47     SSA_PROP_NOT_INTERESTING,
  48
  49     /* The statement produces an interesting value.  The set SSA_NAMEs
  50        returned by SSA_PROP_VISIT_STMT should be added to
  51        INTERESTING_SSA_EDGES.  If the statement being visited is a
  52        conditional jump, SSA_PROP_VISIT_STMT should indicate which edge
  53        out of the basic block should be marked executable.  */
  54     SSA_PROP_INTERESTING,
  55
  56     /* The statement produces a varying (i.e., useless) value and
  57        should not be simulated again.  If the statement being visited
  58        is a conditional jump, all the edges coming out of the block
  59        will be considered executable.  */
  60     SSA_PROP_VARYING
  61 };
  62
  63
  64 struct prop_value_d {
  65     /* Lattice value.  Each propagator is free to define its own
  66        lattice and this field is only meaningful while propagating.
  67        It will not be used by substitute_and_fold.  */
  68     unsigned lattice_val;
  69
  70     /* Propagated value.  */
  71     tree value;
  72 };
  73
  74 typedef struct prop_value_d prop_value_t;
  75
  76
  77 /* Type of value ranges.  See value_range_d for a description of these
  78    types.  */
  79 enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
  80
  81 /* Range of values that can be associated with an SSA_NAME after VRP
  82    has executed.  */
  83 struct value_range_d
  84 {
  85   /* Lattice value represented by this range.  */
  86   enum value_range_type type;
  87
  88   /* Minimum and maximum values represented by this range.  These
  89      values should be interpreted as follows:
  90
  91         - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
  92           be NULL.
  93
  94         - If TYPE == VR_RANGE then MIN holds the minimum value and
  95           MAX holds the maximum value of the range [MIN, MAX].
  96
  97         - If TYPE == ANTI_RANGE the variable is known to NOT
  98           take any values in the range [MIN, MAX].  */
  99   tree min;
 100   tree max;
 101
 102   /* Set of SSA names whose value ranges are equivalent to this one.
 103      This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE.  */
 104   bitmap equiv;
 105 };
 106
 107 typedef struct value_range_d value_range_t;
 108
 109
 110 /* Call-back functions used by the value propagation engine.  */
 111 typedef enum ssa_prop_result (*ssa_prop_visit_stmt_fn) (gimple, edge *, tree *);
 112 typedef enum ssa_prop_result (*ssa_prop_visit_phi_fn) (gimple);
 113 typedef bool (*ssa_prop_fold_stmt_fn) (gimple_stmt_iterator *gsi);
 114
 115
 116 /* In tree-ssa-propagate.c  */
 117 void ssa_propagate (ssa_prop_visit_stmt_fn, ssa_prop_visit_phi_fn);
 118 bool valid_gimple_rhs_p (tree);
 119 bool valid_gimple_call_p (tree);
 120 void move_ssa_defining_stmt_for_defs (gimple, gimple);
 121 bool update_call_from_tree (gimple_stmt_iterator *, tree);
 122 bool stmt_makes_single_store (gimple);
 123 bool substitute_and_fold (prop_value_t *, ssa_prop_fold_stmt_fn);
 124
 125 #endif /* _TREE_SSA_PROPAGATE_H  */