gcc/tree-chrec.h

   1 /* Chains of recurrences.
   2    Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
   3    Free Software Foundation, Inc.
   4    Contributed by Sebastian Pop <pop@cri.ensmp.fr>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 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 GCC_TREE_CHREC_H
  23 #define GCC_TREE_CHREC_H
  24
  25 /* The following trees are unique elements.  Thus the comparison of another
  26    element to these elements should be done on the pointer to these trees,
  27    and not on their value.  */
  28
  29 extern tree chrec_not_analyzed_yet;
  30 extern GTY(()) tree chrec_dont_know;
  31 extern GTY(()) tree chrec_known;
  32
  33 /* After having added an automatically generated element, please
  34    include it in the following function.  */
  35
  36 static inline bool
  37 automatically_generated_chrec_p (const_tree chrec)
  38 {
  39   return (chrec == chrec_dont_know
  40           || chrec == chrec_known);
  41 }
  42
  43 /* The tree nodes aka. CHRECs.  */
  44
  45 static inline bool
  46 tree_is_chrec (const_tree expr)
  47 {
  48   if (TREE_CODE (expr) == POLYNOMIAL_CHREC
  49       || automatically_generated_chrec_p (expr))
  50     return true;
  51   else
  52     return false;
  53 }
  54
  55 \f
  56
  57 /* Chrec folding functions.  */
  58 extern tree chrec_fold_plus (tree, tree, tree);
  59 extern tree chrec_fold_minus (tree, tree, tree);
  60 extern tree chrec_fold_multiply (tree, tree, tree);
  61 extern tree chrec_convert (tree, tree, gimple);
  62 extern tree chrec_convert_rhs (tree, tree, gimple);
  63 extern tree chrec_convert_aggressive (tree, tree);
  64
  65 /* Operations.  */
  66 extern tree chrec_apply (unsigned, tree, tree);
  67 extern tree chrec_replace_initial_condition (tree, tree);
  68 extern tree initial_condition (tree);
  69 extern tree initial_condition_in_loop_num (tree, unsigned);
  70 extern tree evolution_part_in_loop_num (tree, unsigned);
  71 extern tree hide_evolution_in_other_loops_than_loop (tree, unsigned);
  72 extern tree reset_evolution_in_loop (unsigned, tree, tree);
  73 extern tree chrec_merge (tree, tree);
  74 extern void for_each_scev_op (tree *, bool (*) (tree *, void *), void *);
  75
  76 /* Observers.  */
  77 extern bool eq_evolutions_p (const_tree, const_tree);
  78 extern bool is_multivariate_chrec (const_tree);
  79 extern bool chrec_is_positive (tree, bool *);
  80 extern bool chrec_contains_symbols (const_tree);
  81 extern bool chrec_contains_symbols_defined_in_loop (const_tree, unsigned);
  82 extern bool chrec_contains_undetermined (const_tree);
  83 extern bool tree_contains_chrecs (const_tree, int *);
  84 extern bool evolution_function_is_affine_multivariate_p (const_tree, int);
  85 extern bool evolution_function_is_univariate_p (const_tree);
  86 extern unsigned nb_vars_in_chrec (tree);
  87 extern bool evolution_function_is_invariant_p (tree, int);
  88 extern bool scev_is_linear_expression (tree);
  89 extern bool evolution_function_right_is_integer_cst (const_tree);
  90
  91 /* Determines whether CHREC is equal to zero.  */
  92
  93 static inline bool
  94 chrec_zerop (const_tree chrec)
  95 {
  96   if (chrec == NULL_TREE)
  97     return false;
  98
  99   if (TREE_CODE (chrec) == INTEGER_CST)
 100     return integer_zerop (chrec);
 101
 102   return false;
 103 }
 104
 105 /* Determines whether CHREC is a loop invariant with respect to LOOP_NUM.
 106    Set the result in RES and return true when the property can be computed.  */
 107
 108 static inline bool
 109 no_evolution_in_loop_p (tree chrec, unsigned loop_num, bool *res)
 110 {
 111   tree scev;
 112
 113   if (chrec == chrec_not_analyzed_yet
 114       || chrec == chrec_dont_know
 115       || chrec_contains_symbols_defined_in_loop (chrec, loop_num))
 116     return false;
 117
 118   scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
 119   *res = !tree_is_chrec (scev);
 120   return true;
 121 }
 122
 123 /* Build a polynomial chain of recurrence.  */
 124
 125 static inline tree
 126 build_polynomial_chrec (unsigned loop_num,
 127                         tree left,
 128                         tree right)
 129 {
 130   bool val;
 131
 132   if (left == chrec_dont_know
 133       || right == chrec_dont_know)
 134     return chrec_dont_know;
 135
 136   if (!no_evolution_in_loop_p (left, loop_num, &val)
 137       || !val)
 138     return chrec_dont_know;
 139
 140   /* Pointer types should occur only on the left hand side, i.e. in
 141      the base of the chrec, and not in the step.  */
 142   gcc_assert (!POINTER_TYPE_P (TREE_TYPE (right)));
 143
 144   /* Types of left and right sides of a chrec should be compatible.  */
 145   if (POINTER_TYPE_P (TREE_TYPE (left)))
 146     gcc_assert (sizetype == TREE_TYPE (right));
 147   else
 148     gcc_assert (TREE_TYPE (left) == TREE_TYPE (right));
 149
 150   if (chrec_zerop (right))
 151     return left;
 152
 153   return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
 154                  build_int_cst (NULL_TREE, loop_num), left, right);
 155 }
 156
 157 /* Determines whether the expression CHREC is a constant.  */
 158
 159 static inline bool
 160 evolution_function_is_constant_p (const_tree chrec)
 161 {
 162   if (chrec == NULL_TREE)
 163     return false;
 164
 165   switch (TREE_CODE (chrec))
 166     {
 167     case INTEGER_CST:
 168     case REAL_CST:
 169       return true;
 170
 171     default:
 172       return false;
 173     }
 174 }
 175
 176 /* Determine whether CHREC is an affine evolution function in LOOPNUM.  */
 177
 178 static inline bool
 179 evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
 180 {
 181   if (chrec == NULL_TREE)
 182     return false;
 183
 184   switch (TREE_CODE (chrec))
 185     {
 186     case POLYNOMIAL_CHREC:
 187       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
 188           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
 189         return true;
 190       else
 191         return false;
 192
 193     default:
 194       return false;
 195     }
 196 }
 197
 198 /* Determine whether CHREC is an affine evolution function or not.  */
 199
 200 static inline bool
 201 evolution_function_is_affine_p (const_tree chrec)
 202 {
 203   if (chrec == NULL_TREE)
 204     return false;
 205
 206   switch (TREE_CODE (chrec))
 207     {
 208     case POLYNOMIAL_CHREC:
 209       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec),
 210                                              CHREC_VARIABLE (chrec))
 211           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
 212                                                 CHREC_VARIABLE (chrec)))
 213         return true;
 214       else
 215         return false;
 216
 217     default:
 218       return false;
 219     }
 220 }
 221
 222 /* Determines whether EXPR does not contains chrec expressions.  */
 223
 224 static inline bool
 225 tree_does_not_contain_chrecs (const_tree expr)
 226 {
 227   return !tree_contains_chrecs (expr, NULL);
 228 }
 229
 230 /* Returns the type of the chrec.  */
 231
 232 static inline tree
 233 chrec_type (const_tree chrec)
 234 {
 235   if (automatically_generated_chrec_p (chrec))
 236     return NULL_TREE;
 237
 238   return TREE_TYPE (chrec);
 239 }
 240
 241 static inline tree
 242 chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
 243 {
 244   switch (code)
 245     {
 246     case PLUS_EXPR:
 247       return chrec_fold_plus (type, op0, op1);
 248
 249     case MINUS_EXPR:
 250       return chrec_fold_minus (type, op0, op1);
 251
 252     case MULT_EXPR:
 253       return chrec_fold_multiply (type, op0, op1);
 254
 255     default:
 256       gcc_unreachable ();
 257     }
 258
 259 }
 260
 261 #endif  /* GCC_TREE_CHREC_H  */