gcc/tree-chrec.h

   1 /* Chains of recurrences.
   2    Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   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_apply_map (tree, VEC (tree, heap) *);
  68 extern tree chrec_replace_initial_condition (tree, tree);
  69 extern tree initial_condition (tree);
  70 extern tree initial_condition_in_loop_num (tree, unsigned);
  71 extern tree evolution_part_in_loop_num (tree, unsigned);
  72 extern tree hide_evolution_in_other_loops_than_loop (tree, unsigned);
  73 extern tree reset_evolution_in_loop (unsigned, tree, tree);
  74 extern tree chrec_merge (tree, tree);
  75 extern void for_each_scev_op (tree *, bool (*) (tree *, void *), void *);
  76
  77 /* Observers.  */
  78 extern bool eq_evolutions_p (const_tree, const_tree);
  79 extern bool is_multivariate_chrec (const_tree);
  80 extern bool chrec_is_positive (tree, bool *);
  81 extern bool chrec_contains_symbols (const_tree);
  82 extern bool chrec_contains_symbols_defined_in_loop (const_tree, unsigned);
  83 extern bool chrec_contains_undetermined (const_tree);
  84 extern bool tree_contains_chrecs (const_tree, int *);
  85 extern bool evolution_function_is_affine_multivariate_p (const_tree, int);
  86 extern bool evolution_function_is_univariate_p (const_tree);
  87 extern unsigned nb_vars_in_chrec (tree);
  88 extern bool evolution_function_is_invariant_p (tree, int);
  89 extern bool scev_is_linear_expression (tree);
  90 extern bool evolution_function_right_is_integer_cst (const_tree);
  91
  92 /* Determines whether CHREC is equal to zero.  */
  93
  94 static inline bool
  95 chrec_zerop (const_tree chrec)
  96 {
  97   if (chrec == NULL_TREE)
  98     return false;
  99
 100   if (TREE_CODE (chrec) == INTEGER_CST)
 101     return integer_zerop (chrec);
 102
 103   return false;
 104 }
 105
 106 /* Determines whether CHREC is a loop invariant with respect to LOOP_NUM.
 107    Set the result in RES and return true when the property can be computed.  */
 108
 109 static inline bool
 110 no_evolution_in_loop_p (tree chrec, unsigned loop_num, bool *res)
 111 {
 112   tree scev;
 113
 114   if (chrec == chrec_not_analyzed_yet
 115       || chrec == chrec_dont_know
 116       || chrec_contains_symbols_defined_in_loop (chrec, loop_num))
 117     return false;
 118
 119   STRIP_NOPS (chrec);
 120   scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
 121   *res = !tree_is_chrec (scev);
 122   return true;
 123 }
 124
 125 /* Build a polynomial chain of recurrence.  */
 126
 127 static inline tree
 128 build_polynomial_chrec (unsigned loop_num,
 129                         tree left,
 130                         tree right)
 131 {
 132   bool val;
 133
 134   if (left == chrec_dont_know
 135       || right == chrec_dont_know)
 136     return chrec_dont_know;
 137
 138   if (!no_evolution_in_loop_p (left, loop_num, &val)
 139       || !val)
 140     return chrec_dont_know;
 141
 142   /* Pointer types should occur only on the left hand side, i.e. in
 143      the base of the chrec, and not in the step.  */
 144   gcc_assert (!POINTER_TYPE_P (TREE_TYPE (right)));
 145
 146   /* Types of left and right sides of a chrec should be compatible.  */
 147   if (POINTER_TYPE_P (TREE_TYPE (left)))
 148     gcc_assert (ptrofftype_p (TREE_TYPE (right)));
 149   else
 150     gcc_assert (TREE_TYPE (left) == TREE_TYPE (right));
 151
 152   if (chrec_zerop (right))
 153     return left;
 154
 155   return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
 156                  build_int_cst (NULL_TREE, loop_num), left, right);
 157 }
 158
 159 /* Determines whether the expression CHREC is a constant.  */
 160
 161 static inline bool
 162 evolution_function_is_constant_p (const_tree chrec)
 163 {
 164   if (chrec == NULL_TREE)
 165     return false;
 166
 167   switch (TREE_CODE (chrec))
 168     {
 169     case INTEGER_CST:
 170     case REAL_CST:
 171       return true;
 172
 173     default:
 174       return false;
 175     }
 176 }
 177
 178 /* Determine whether CHREC is an affine evolution function in LOOPNUM.  */
 179
 180 static inline bool
 181 evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
 182 {
 183   if (chrec == NULL_TREE)
 184     return false;
 185
 186   switch (TREE_CODE (chrec))
 187     {
 188     case POLYNOMIAL_CHREC:
 189       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
 190           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
 191         return true;
 192       else
 193         return false;
 194
 195     default:
 196       return false;
 197     }
 198 }
 199
 200 /* Determine whether CHREC is an affine evolution function or not.  */
 201
 202 static inline bool
 203 evolution_function_is_affine_p (const_tree chrec)
 204 {
 205   return chrec
 206     && TREE_CODE (chrec) == POLYNOMIAL_CHREC
 207     && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
 208                                           CHREC_VARIABLE (chrec))
 209     && (TREE_CODE (CHREC_RIGHT (chrec)) != POLYNOMIAL_CHREC
 210         || evolution_function_is_affine_p (CHREC_RIGHT (chrec)));
 211 }
 212
 213 /* Determines whether EXPR does not contains chrec expressions.  */
 214
 215 static inline bool
 216 tree_does_not_contain_chrecs (const_tree expr)
 217 {
 218   return !tree_contains_chrecs (expr, NULL);
 219 }
 220
 221 /* Returns the type of the chrec.  */
 222
 223 static inline tree
 224 chrec_type (const_tree chrec)
 225 {
 226   if (automatically_generated_chrec_p (chrec))
 227     return NULL_TREE;
 228
 229   return TREE_TYPE (chrec);
 230 }
 231
 232 static inline tree
 233 chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
 234 {
 235   switch (code)
 236     {
 237     case PLUS_EXPR:
 238       return chrec_fold_plus (type, op0, op1);
 239
 240     case MINUS_EXPR:
 241       return chrec_fold_minus (type, op0, op1);
 242
 243     case MULT_EXPR:
 244       return chrec_fold_multiply (type, op0, op1);
 245
 246     default:
 247       gcc_unreachable ();
 248     }
 249
 250 }
 251
 252 #endif  /* GCC_TREE_CHREC_H  */