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
  90 /* Determines whether CHREC is equal to zero.  */
  91
  92 static inline bool
  93 chrec_zerop (const_tree chrec)
  94 {
  95   if (chrec == NULL_TREE)
  96     return false;
  97
  98   if (TREE_CODE (chrec) == INTEGER_CST)
  99     return integer_zerop (chrec);
 100
 101   return false;
 102 }
 103
 104 /* Determines whether CHREC is a loop invariant with respect to LOOP_NUM.
 105    Set the result in RES and return true when the property can be computed.  */
 106
 107 static inline bool
 108 no_evolution_in_loop_p (tree chrec, unsigned loop_num, bool *res)
 109 {
 110   tree scev;
 111
 112   if (chrec == chrec_not_analyzed_yet
 113       || chrec == chrec_dont_know
 114       || chrec_contains_symbols_defined_in_loop (chrec, loop_num))
 115     return false;
 116
 117   scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
 118   *res = !tree_is_chrec (scev);
 119   return true;
 120 }
 121
 122 /* Build a polynomial chain of recurrence.  */
 123
 124 static inline tree
 125 build_polynomial_chrec (unsigned loop_num,
 126                         tree left,
 127                         tree right)
 128 {
 129   bool val;
 130
 131   if (left == chrec_dont_know
 132       || right == chrec_dont_know)
 133     return chrec_dont_know;
 134
 135   if (no_evolution_in_loop_p (left, loop_num, &val) && !val)
 136     return chrec_dont_know;
 137
 138   /* Pointer types should occur only on the left hand side, i.e. in
 139      the base of the chrec, and not in the step.  */
 140   gcc_assert (!POINTER_TYPE_P (TREE_TYPE (right)));
 141
 142   /* Types of left and right sides of a chrec should be compatible.  */
 143   if (POINTER_TYPE_P (TREE_TYPE (left)))
 144     gcc_assert (sizetype == TREE_TYPE (right));
 145   else
 146     gcc_assert (TREE_TYPE (left) == TREE_TYPE (right));
 147
 148   if (chrec_zerop (right))
 149     return left;
 150
 151   return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
 152                  build_int_cst (NULL_TREE, loop_num), left, right);
 153 }
 154
 155 /* Determines whether the expression CHREC is a constant.  */
 156
 157 static inline bool
 158 evolution_function_is_constant_p (const_tree chrec)
 159 {
 160   if (chrec == NULL_TREE)
 161     return false;
 162
 163   switch (TREE_CODE (chrec))
 164     {
 165     case INTEGER_CST:
 166     case REAL_CST:
 167       return true;
 168
 169     default:
 170       return false;
 171     }
 172 }
 173
 174 /* Determine whether CHREC is an affine evolution function in LOOPNUM.  */
 175
 176 static inline bool
 177 evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
 178 {
 179   if (chrec == NULL_TREE)
 180     return false;
 181
 182   switch (TREE_CODE (chrec))
 183     {
 184     case POLYNOMIAL_CHREC:
 185       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
 186           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
 187         return true;
 188       else
 189         return false;
 190
 191     default:
 192       return false;
 193     }
 194 }
 195
 196 /* Determine whether CHREC is an affine evolution function or not.  */
 197
 198 static inline bool
 199 evolution_function_is_affine_p (const_tree chrec)
 200 {
 201   if (chrec == NULL_TREE)
 202     return false;
 203
 204   switch (TREE_CODE (chrec))
 205     {
 206     case POLYNOMIAL_CHREC:
 207       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec),
 208                                              CHREC_VARIABLE (chrec))
 209           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
 210                                                 CHREC_VARIABLE (chrec)))
 211         return true;
 212       else
 213         return false;
 214
 215     default:
 216       return false;
 217     }
 218 }
 219
 220 /* Determines whether EXPR does not contains chrec expressions.  */
 221
 222 static inline bool
 223 tree_does_not_contain_chrecs (const_tree expr)
 224 {
 225   return !tree_contains_chrecs (expr, NULL);
 226 }
 227
 228 /* Returns the type of the chrec.  */
 229
 230 static inline tree
 231 chrec_type (const_tree chrec)
 232 {
 233   if (automatically_generated_chrec_p (chrec))
 234     return NULL_TREE;
 235
 236   return TREE_TYPE (chrec);
 237 }
 238
 239 static inline tree
 240 chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
 241 {
 242   switch (code)
 243     {
 244     case PLUS_EXPR:
 245       return chrec_fold_plus (type, op0, op1);
 246
 247     case MINUS_EXPR:
 248       return chrec_fold_minus (type, op0, op1);
 249
 250     case MULT_EXPR:
 251       return chrec_fold_multiply (type, op0, op1);
 252
 253     default:
 254       gcc_unreachable ();
 255     }
 256
 257 }
 258
 259 #endif  /* GCC_TREE_CHREC_H  */