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