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, gimple);
  61 extern tree chrec_convert_rhs (tree, tree, gimple);
  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 extern void for_each_scev_op (tree *, bool (*) (tree *, void *), void *);
  74
  75 /* Observers.  */
  76 extern bool eq_evolutions_p (const_tree, const_tree);
  77 extern bool is_multivariate_chrec (const_tree);
  78 extern bool chrec_is_positive (tree, bool *);
  79 extern bool chrec_contains_symbols (const_tree);
  80 extern bool chrec_contains_symbols_defined_in_loop (const_tree, unsigned);
  81 extern bool chrec_contains_undetermined (const_tree);
  82 extern bool tree_contains_chrecs (const_tree, int *);
  83 extern bool evolution_function_is_affine_multivariate_p (const_tree, int);
  84 extern bool evolution_function_is_univariate_p (const_tree);
  85 extern unsigned nb_vars_in_chrec (tree);
  86 extern bool evolution_function_is_invariant_p (tree, int);
  87
  88 /* Determines whether CHREC is equal to zero.  */
  89
  90 static inline bool
  91 chrec_zerop (const_tree chrec)
  92 {
  93   if (chrec == NULL_TREE)
  94     return false;
  95
  96   if (TREE_CODE (chrec) == INTEGER_CST)
  97     return integer_zerop (chrec);
  98
  99   return false;
 100 }
 101
 102 /* Determines whether CHREC is a loop invariant with respect to LOOP_NUM.
 103    Set the result in RES and return true when the property can be computed.  */
 104
 105 static inline bool
 106 no_evolution_in_loop_p (tree chrec, unsigned loop_num, bool *res)
 107 {
 108   tree scev;
 109
 110   if (chrec == chrec_not_analyzed_yet
 111       || chrec == chrec_dont_know
 112       || chrec_contains_symbols_defined_in_loop (chrec, loop_num))
 113     return false;
 114
 115   scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
 116   *res = !tree_is_chrec (scev);
 117   return true;
 118 }
 119
 120 /* Build a polynomial chain of recurrence.  */
 121
 122 static inline tree
 123 build_polynomial_chrec (unsigned loop_num,
 124                         tree left,
 125                         tree right)
 126 {
 127   bool val;
 128
 129   if (left == chrec_dont_know
 130       || right == chrec_dont_know)
 131     return chrec_dont_know;
 132
 133   if (no_evolution_in_loop_p (left, loop_num, &val) && !val)
 134     return chrec_dont_know;
 135
 136   /* Pointer types should occur only on the left hand side, i.e. in
 137      the base of the chrec, and not in the step.  */
 138   gcc_assert (!POINTER_TYPE_P (TREE_TYPE (right)));
 139
 140   /* Types of left and right sides of a chrec should be compatible.  */
 141   if (POINTER_TYPE_P (TREE_TYPE (left)))
 142     gcc_assert (sizetype == TREE_TYPE (right));
 143   else
 144     gcc_assert (TREE_TYPE (left) == TREE_TYPE (right));
 145
 146   if (chrec_zerop (right))
 147     return left;
 148
 149   return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
 150                  build_int_cst (NULL_TREE, loop_num), left, right);
 151 }
 152
 153 /* Determines whether the expression CHREC is a constant.  */
 154
 155 static inline bool
 156 evolution_function_is_constant_p (const_tree chrec)
 157 {
 158   if (chrec == NULL_TREE)
 159     return false;
 160
 161   switch (TREE_CODE (chrec))
 162     {
 163     case INTEGER_CST:
 164     case REAL_CST:
 165       return true;
 166
 167     default:
 168       return false;
 169     }
 170 }
 171
 172 /* Determine whether CHREC is an affine evolution function in LOOPNUM.  */
 173
 174 static inline bool
 175 evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
 176 {
 177   if (chrec == NULL_TREE)
 178     return false;
 179
 180   switch (TREE_CODE (chrec))
 181     {
 182     case POLYNOMIAL_CHREC:
 183       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
 184           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
 185         return true;
 186       else
 187         return false;
 188
 189     default:
 190       return false;
 191     }
 192 }
 193
 194 /* Determine whether CHREC is an affine evolution function or not.  */
 195
 196 static inline bool
 197 evolution_function_is_affine_p (const_tree chrec)
 198 {
 199   if (chrec == NULL_TREE)
 200     return false;
 201
 202   switch (TREE_CODE (chrec))
 203     {
 204     case POLYNOMIAL_CHREC:
 205       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec),
 206                                              CHREC_VARIABLE (chrec))
 207           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
 208                                                 CHREC_VARIABLE (chrec)))
 209         return true;
 210       else
 211         return false;
 212
 213     default:
 214       return false;
 215     }
 216 }
 217
 218 /* Determines whether EXPR does not contains chrec expressions.  */
 219
 220 static inline bool
 221 tree_does_not_contain_chrecs (const_tree expr)
 222 {
 223   return !tree_contains_chrecs (expr, NULL);
 224 }
 225
 226 /* Returns the type of the chrec.  */
 227
 228 static inline tree
 229 chrec_type (const_tree chrec)
 230 {
 231   if (automatically_generated_chrec_p (chrec))
 232     return NULL_TREE;
 233
 234   return TREE_TYPE (chrec);
 235 }
 236
 237 static inline tree
 238 chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
 239 {
 240   switch (code)
 241     {
 242     case PLUS_EXPR:
 243       return chrec_fold_plus (type, op0, op1);
 244
 245     case MINUS_EXPR:
 246       return chrec_fold_minus (type, op0, op1);
 247
 248     case MULT_EXPR:
 249       return chrec_fold_multiply (type, op0, op1);
 250
 251     default:
 252       gcc_unreachable ();
 253     }
 254
 255 }
 256
 257 #endif  /* GCC_TREE_CHREC_H  */