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)
 136       || !val)
 137     return chrec_dont_know;
 138
 139   /* Pointer types should occur only on the left hand side, i.e. in
 140      the base of the chrec, and not in the step.  */
 141   gcc_assert (!POINTER_TYPE_P (TREE_TYPE (right)));
 142
 143   /* Types of left and right sides of a chrec should be compatible.  */
 144   if (POINTER_TYPE_P (TREE_TYPE (left)))
 145     gcc_assert (sizetype == TREE_TYPE (right));
 146   else
 147     gcc_assert (TREE_TYPE (left) == TREE_TYPE (right));
 148
 149   if (chrec_zerop (right))
 150     return left;
 151
 152   return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
 153                  build_int_cst (NULL_TREE, loop_num), left, right);
 154 }
 155
 156 /* Determines whether the expression CHREC is a constant.  */
 157
 158 static inline bool
 159 evolution_function_is_constant_p (const_tree chrec)
 160 {
 161   if (chrec == NULL_TREE)
 162     return false;
 163
 164   switch (TREE_CODE (chrec))
 165     {
 166     case INTEGER_CST:
 167     case REAL_CST:
 168       return true;
 169
 170     default:
 171       return false;
 172     }
 173 }
 174
 175 /* Determine whether CHREC is an affine evolution function in LOOPNUM.  */
 176
 177 static inline bool
 178 evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
 179 {
 180   if (chrec == NULL_TREE)
 181     return false;
 182
 183   switch (TREE_CODE (chrec))
 184     {
 185     case POLYNOMIAL_CHREC:
 186       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
 187           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
 188         return true;
 189       else
 190         return false;
 191
 192     default:
 193       return false;
 194     }
 195 }
 196
 197 /* Determine whether CHREC is an affine evolution function or not.  */
 198
 199 static inline bool
 200 evolution_function_is_affine_p (const_tree chrec)
 201 {
 202   if (chrec == NULL_TREE)
 203     return false;
 204
 205   switch (TREE_CODE (chrec))
 206     {
 207     case POLYNOMIAL_CHREC:
 208       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec),
 209                                              CHREC_VARIABLE (chrec))
 210           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
 211                                                 CHREC_VARIABLE (chrec)))
 212         return true;
 213       else
 214         return false;
 215
 216     default:
 217       return false;
 218     }
 219 }
 220
 221 /* Determines whether EXPR does not contains chrec expressions.  */
 222
 223 static inline bool
 224 tree_does_not_contain_chrecs (const_tree expr)
 225 {
 226   return !tree_contains_chrecs (expr, NULL);
 227 }
 228
 229 /* Returns the type of the chrec.  */
 230
 231 static inline tree
 232 chrec_type (const_tree chrec)
 233 {
 234   if (automatically_generated_chrec_p (chrec))
 235     return NULL_TREE;
 236
 237   return TREE_TYPE (chrec);
 238 }
 239
 240 static inline tree
 241 chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
 242 {
 243   switch (code)
 244     {
 245     case PLUS_EXPR:
 246       return chrec_fold_plus (type, op0, op1);
 247
 248     case MINUS_EXPR:
 249       return chrec_fold_minus (type, op0, op1);
 250
 251     case MULT_EXPR:
 252       return chrec_fold_multiply (type, op0, op1);
 253
 254     default:
 255       gcc_unreachable ();
 256     }
 257
 258 }
 259
 260 #endif  /* GCC_TREE_CHREC_H  */