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 extern bool evolution_function_right_is_integer_cst (const_tree);
  90
  91 /* Determines whether CHREC is equal to zero.  */
  92
  93 static inline bool
  94 chrec_zerop (const_tree chrec)
  95 {
  96   if (chrec == NULL_TREE)
  97     return false;
  98
  99   if (TREE_CODE (chrec) == INTEGER_CST)
 100     return integer_zerop (chrec);
 101
 102   return false;
 103 }
 104
 105 /* Determines whether CHREC is a loop invariant with respect to LOOP_NUM.
 106    Set the result in RES and return true when the property can be computed.  */
 107
 108 static inline bool
 109 no_evolution_in_loop_p (tree chrec, unsigned loop_num, bool *res)
 110 {
 111   tree scev;
 112
 113   if (chrec == chrec_not_analyzed_yet
 114       || chrec == chrec_dont_know
 115       || chrec_contains_symbols_defined_in_loop (chrec, loop_num))
 116     return false;
 117
 118   STRIP_NOPS (chrec);
 119   scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
 120   *res = !tree_is_chrec (scev);
 121   return true;
 122 }
 123
 124 /* Build a polynomial chain of recurrence.  */
 125
 126 static inline tree
 127 build_polynomial_chrec (unsigned loop_num,
 128                         tree left,
 129                         tree right)
 130 {
 131   bool val;
 132
 133   if (left == chrec_dont_know
 134       || right == chrec_dont_know)
 135     return chrec_dont_know;
 136
 137   if (!no_evolution_in_loop_p (left, loop_num, &val)
 138       || !val)
 139     return chrec_dont_know;
 140
 141   /* Pointer types should occur only on the left hand side, i.e. in
 142      the base of the chrec, and not in the step.  */
 143   gcc_assert (!POINTER_TYPE_P (TREE_TYPE (right)));
 144
 145   /* Types of left and right sides of a chrec should be compatible.  */
 146   if (POINTER_TYPE_P (TREE_TYPE (left)))
 147     gcc_assert (sizetype == TREE_TYPE (right));
 148   else
 149     gcc_assert (TREE_TYPE (left) == TREE_TYPE (right));
 150
 151   if (chrec_zerop (right))
 152     return left;
 153
 154   return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
 155                  build_int_cst (NULL_TREE, loop_num), left, right);
 156 }
 157
 158 /* Determines whether the expression CHREC is a constant.  */
 159
 160 static inline bool
 161 evolution_function_is_constant_p (const_tree chrec)
 162 {
 163   if (chrec == NULL_TREE)
 164     return false;
 165
 166   switch (TREE_CODE (chrec))
 167     {
 168     case INTEGER_CST:
 169     case REAL_CST:
 170       return true;
 171
 172     default:
 173       return false;
 174     }
 175 }
 176
 177 /* Determine whether CHREC is an affine evolution function in LOOPNUM.  */
 178
 179 static inline bool
 180 evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
 181 {
 182   if (chrec == NULL_TREE)
 183     return false;
 184
 185   switch (TREE_CODE (chrec))
 186     {
 187     case POLYNOMIAL_CHREC:
 188       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
 189           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
 190         return true;
 191       else
 192         return false;
 193
 194     default:
 195       return false;
 196     }
 197 }
 198
 199 /* Determine whether CHREC is an affine evolution function or not.  */
 200
 201 static inline bool
 202 evolution_function_is_affine_p (const_tree chrec)
 203 {
 204   if (chrec == NULL_TREE)
 205     return false;
 206
 207   switch (TREE_CODE (chrec))
 208     {
 209     case POLYNOMIAL_CHREC:
 210       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec),
 211                                              CHREC_VARIABLE (chrec))
 212           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
 213                                                 CHREC_VARIABLE (chrec)))
 214         return true;
 215       else
 216         return false;
 217
 218     default:
 219       return false;
 220     }
 221 }
 222
 223 /* Determines whether EXPR does not contains chrec expressions.  */
 224
 225 static inline bool
 226 tree_does_not_contain_chrecs (const_tree expr)
 227 {
 228   return !tree_contains_chrecs (expr, NULL);
 229 }
 230
 231 /* Returns the type of the chrec.  */
 232
 233 static inline tree
 234 chrec_type (const_tree chrec)
 235 {
 236   if (automatically_generated_chrec_p (chrec))
 237     return NULL_TREE;
 238
 239   return TREE_TYPE (chrec);
 240 }
 241
 242 static inline tree
 243 chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
 244 {
 245   switch (code)
 246     {
 247     case PLUS_EXPR:
 248       return chrec_fold_plus (type, op0, op1);
 249
 250     case MINUS_EXPR:
 251       return chrec_fold_minus (type, op0, op1);
 252
 253     case MULT_EXPR:
 254       return chrec_fold_multiply (type, op0, op1);
 255
 256     default:
 257       gcc_unreachable ();
 258     }
 259
 260 }
 261
 262 #endif  /* GCC_TREE_CHREC_H  */