gcc/tree-chrec.h

   1 /* Chains of recurrences.
   2    Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
   3    Contributed by Sebastian Pop <pop@cri.ensmp.fr>
   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_TREE_CHREC_H
  22 #define GCC_TREE_CHREC_H
  23
  24 /* The following trees are unique elements.  Thus the comparison of another
  25    element to these elements should be done on the pointer to these trees,
  26    and not on their value.  */
  27
  28 extern tree chrec_not_analyzed_yet;
  29 extern GTY(()) tree chrec_dont_know;
  30 extern GTY(()) tree chrec_known;
  31
  32 /* After having added an automatically generated element, please
  33    include it in the following function.  */
  34
  35 static inline bool
  36 automatically_generated_chrec_p (const_tree chrec)
  37 {
  38   return (chrec == chrec_dont_know
  39           || chrec == chrec_known);
  40 }
  41
  42 /* The tree nodes aka. CHRECs.  */
  43
  44 static inline bool
  45 tree_is_chrec (const_tree expr)
  46 {
  47   if (TREE_CODE (expr) == POLYNOMIAL_CHREC
  48       || automatically_generated_chrec_p (expr))
  49     return true;
  50   else
  51     return false;
  52 }
  53
  54 \f
  55
  56 /* Chrec folding functions.  */
  57 extern tree chrec_fold_plus (tree, tree, tree);
  58 extern tree chrec_fold_minus (tree, tree, tree);
  59 extern tree chrec_fold_multiply (tree, tree, tree);
  60 extern tree chrec_convert (tree, tree, tree);
  61 extern tree chrec_convert_rhs (tree, tree, tree);
  62 extern tree chrec_convert_aggressive (tree, tree);
  63
  64 /* Operations.  */
  65 extern tree chrec_apply (unsigned, tree, tree);
  66 extern tree chrec_replace_initial_condition (tree, tree);
  67 extern tree initial_condition (tree);
  68 extern tree initial_condition_in_loop_num (tree, unsigned);
  69 extern tree evolution_part_in_loop_num (tree, unsigned);
  70 extern tree hide_evolution_in_other_loops_than_loop (tree, unsigned);
  71 extern tree reset_evolution_in_loop (unsigned, tree, tree);
  72 extern tree chrec_merge (tree, tree);
  73
  74 /* Observers.  */
  75 extern bool eq_evolutions_p (const_tree, const_tree);
  76 extern bool is_multivariate_chrec (const_tree);
  77 extern bool chrec_is_positive (tree, bool *);
  78 extern bool chrec_contains_symbols (const_tree);
  79 extern bool chrec_contains_symbols_defined_in_loop (const_tree, unsigned);
  80 extern bool chrec_contains_undetermined (const_tree);
  81 extern bool tree_contains_chrecs (const_tree, int *);
  82 extern bool evolution_function_is_affine_multivariate_p (const_tree, int);
  83 extern bool evolution_function_is_univariate_p (const_tree);
  84 extern unsigned nb_vars_in_chrec (tree);
  85 extern bool evolution_function_is_invariant_p (tree, int);
  86
  87 /* Determines whether CHREC is equal to zero.  */
  88
  89 static inline bool
  90 chrec_zerop (const_tree chrec)
  91 {
  92   if (chrec == NULL_TREE)
  93     return false;
  94
  95   if (TREE_CODE (chrec) == INTEGER_CST)
  96     return integer_zerop (chrec);
  97
  98   return false;
  99 }
 100
 101 /* Determines whether CHREC is a loop invariant with respect to LOOP_NUM.
 102    Set the result in RES and return true when the property can be computed.  */
 103
 104 static inline bool
 105 no_evolution_in_loop_p (tree chrec, unsigned loop_num, bool *res)
 106 {
 107   tree scev;
 108
 109   if (chrec == chrec_not_analyzed_yet
 110       || chrec == chrec_dont_know
 111       || chrec_contains_symbols_defined_in_loop (chrec, loop_num))
 112     return false;
 113
 114   scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
 115   *res = !tree_is_chrec (scev);
 116   return true;
 117 }
 118
 119 /* Build a polynomial chain of recurrence.  */
 120
 121 static inline tree
 122 build_polynomial_chrec (unsigned loop_num,
 123                         tree left,
 124                         tree right)
 125 {
 126   bool val;
 127
 128   if (left == chrec_dont_know
 129       || right == chrec_dont_know)
 130     return chrec_dont_know;
 131
 132   if (no_evolution_in_loop_p (left, loop_num, &val) && !val)
 133     return chrec_dont_know;
 134
 135   if (POINTER_TYPE_P (TREE_TYPE (left)))
 136     gcc_assert (sizetype == TREE_TYPE (right));
 137   else
 138     gcc_assert (TREE_TYPE (left) == TREE_TYPE (right));
 139
 140   if (chrec_zerop (right))
 141     return left;
 142
 143   return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
 144                  build_int_cst (NULL_TREE, loop_num), left, right);
 145 }
 146
 147 /* Determines whether the expression CHREC is a constant.  */
 148
 149 static inline bool
 150 evolution_function_is_constant_p (const_tree chrec)
 151 {
 152   if (chrec == NULL_TREE)
 153     return false;
 154
 155   switch (TREE_CODE (chrec))
 156     {
 157     case INTEGER_CST:
 158     case REAL_CST:
 159       return true;
 160
 161     default:
 162       return false;
 163     }
 164 }
 165
 166 /* Determine whether the given tree is an affine evolution function or not.  */
 167
 168 static inline bool
 169 evolution_function_is_affine_p (const_tree chrec)
 170 {
 171   if (chrec == NULL_TREE)
 172     return false;
 173
 174   switch (TREE_CODE (chrec))
 175     {
 176     case POLYNOMIAL_CHREC:
 177       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec),
 178                                              CHREC_VARIABLE (chrec))
 179           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
 180                                                 CHREC_VARIABLE (chrec)))
 181         return true;
 182       else
 183         return false;
 184
 185     default:
 186       return false;
 187     }
 188 }
 189
 190 /* Determine whether the given tree is an affine or constant evolution
 191    function.  */
 192
 193 static inline bool
 194 evolution_function_is_affine_or_constant_p (const_tree chrec)
 195 {
 196   return evolution_function_is_affine_p (chrec)
 197     || evolution_function_is_constant_p (chrec);
 198 }
 199
 200 /* Determines whether EXPR does not contains chrec expressions.  */
 201
 202 static inline bool
 203 tree_does_not_contain_chrecs (const_tree expr)
 204 {
 205   return !tree_contains_chrecs (expr, NULL);
 206 }
 207
 208 /* Returns the type of the chrec.  */
 209
 210 static inline tree
 211 chrec_type (const_tree chrec)
 212 {
 213   if (automatically_generated_chrec_p (chrec))
 214     return NULL_TREE;
 215
 216   return TREE_TYPE (chrec);
 217 }
 218
 219
 220 #endif  /* GCC_TREE_CHREC_H  */