gcc/tree-chrec.h

   1 /* Chains of recurrences.
   2    Copyright (C) 2003-2017 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 enum ev_direction {EV_DIR_GROWS, EV_DIR_DECREASES, EV_DIR_UNKNOWN};
  56 enum ev_direction scev_direction (const_tree);
  57
  58 /* Chrec folding functions.  */
  59 extern tree chrec_fold_plus (tree, tree, tree);
  60 extern tree chrec_fold_minus (tree, tree, tree);
  61 extern tree chrec_fold_multiply (tree, tree, tree);
  62 extern tree chrec_convert (tree, tree, gimple *, bool = true, tree = NULL);
  63 extern tree chrec_convert_rhs (tree, tree, gimple *);
  64 extern tree chrec_convert_aggressive (tree, tree, bool *);
  65
  66 /* Operations.  */
  67 extern tree chrec_apply (unsigned, tree, tree);
  68 extern tree chrec_apply_map (tree, vec<tree> );
  69 extern tree chrec_replace_initial_condition (tree, tree);
  70 extern tree initial_condition (tree);
  71 extern tree initial_condition_in_loop_num (tree, unsigned);
  72 extern tree evolution_part_in_loop_num (tree, unsigned);
  73 extern tree hide_evolution_in_other_loops_than_loop (tree, unsigned);
  74 extern tree reset_evolution_in_loop (unsigned, tree, tree);
  75 extern tree chrec_merge (tree, tree);
  76 extern void for_each_scev_op (tree *, bool (*) (tree *, void *), void *);
  77 extern bool convert_affine_scev (struct loop *, tree, tree *, tree *, gimple *,
  78                                  bool, tree = NULL);
  79
  80 /* Observers.  */
  81 extern bool eq_evolutions_p (const_tree, const_tree);
  82 extern bool is_multivariate_chrec (const_tree);
  83 extern bool chrec_contains_symbols (const_tree);
  84 extern bool chrec_contains_symbols_defined_in_loop (const_tree, unsigned);
  85 extern bool chrec_contains_undetermined (const_tree);
  86 extern bool tree_contains_chrecs (const_tree, int *);
  87 extern bool evolution_function_is_affine_multivariate_p (const_tree, int);
  88 extern bool evolution_function_is_univariate_p (const_tree);
  89 extern unsigned nb_vars_in_chrec (tree);
  90 extern bool evolution_function_is_invariant_p (tree, int);
  91 extern bool scev_is_linear_expression (tree);
  92 extern bool evolution_function_right_is_integer_cst (const_tree);
  93
  94 /* Determines whether CHREC is equal to zero.  */
  95
  96 static inline bool
  97 chrec_zerop (const_tree chrec)
  98 {
  99   if (chrec == NULL_TREE)
 100     return false;
 101
 102   if (TREE_CODE (chrec) == INTEGER_CST)
 103     return integer_zerop (chrec);
 104
 105   return false;
 106 }
 107
 108 /* Determines whether CHREC is a loop invariant with respect to LOOP_NUM.
 109    Set the result in RES and return true when the property can be computed.  */
 110
 111 static inline bool
 112 no_evolution_in_loop_p (tree chrec, unsigned loop_num, bool *res)
 113 {
 114   tree scev;
 115
 116   if (chrec == chrec_not_analyzed_yet
 117       || chrec == chrec_dont_know
 118       || chrec_contains_symbols_defined_in_loop (chrec, loop_num))
 119     return false;
 120
 121   STRIP_NOPS (chrec);
 122   scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
 123   *res = !tree_contains_chrecs (scev, NULL);
 124   return true;
 125 }
 126
 127 /* Build a polynomial chain of recurrence.  */
 128
 129 static inline tree
 130 build_polynomial_chrec (unsigned loop_num,
 131                         tree left,
 132                         tree right)
 133 {
 134   bool val;
 135
 136   if (left == chrec_dont_know
 137       || right == chrec_dont_know)
 138     return chrec_dont_know;
 139
 140   if (!no_evolution_in_loop_p (left, loop_num, &val)
 141       || !val)
 142     return chrec_dont_know;
 143
 144   /* Types of left and right sides of a chrec should be compatible, but
 145      pointer CHRECs are special in that the evolution is of ptroff type.  */
 146   if (POINTER_TYPE_P (TREE_TYPE (left)))
 147     gcc_checking_assert (ptrofftype_p (TREE_TYPE (right)));
 148   else
 149     {
 150       /* Pointer types should occur only on the left hand side, i.e. in
 151          the base of the chrec, and not in the step.  */
 152       gcc_checking_assert (!POINTER_TYPE_P (TREE_TYPE (right))
 153                            && types_compatible_p (TREE_TYPE (left),
 154                                                   TREE_TYPE (right)));
 155     }
 156
 157   if (chrec_zerop (right))
 158     return left;
 159
 160   tree chrec = build2 (POLYNOMIAL_CHREC, TREE_TYPE (left), left, right);
 161   CHREC_VARIABLE (chrec) = loop_num;
 162   return chrec;
 163 }
 164
 165 /* Determines whether the expression CHREC is a constant.  */
 166
 167 static inline bool
 168 evolution_function_is_constant_p (const_tree chrec)
 169 {
 170   if (chrec == NULL_TREE)
 171     return false;
 172
 173   if (CONSTANT_CLASS_P (chrec))
 174     return true;
 175   return is_gimple_min_invariant (chrec);
 176 }
 177
 178 /* Determine whether CHREC is an affine evolution function in LOOPNUM.  */
 179
 180 static inline bool
 181 evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
 182 {
 183   if (chrec == NULL_TREE)
 184     return false;
 185
 186   switch (TREE_CODE (chrec))
 187     {
 188     case POLYNOMIAL_CHREC:
 189       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
 190           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
 191         return true;
 192       else
 193         return false;
 194
 195     default:
 196       return false;
 197     }
 198 }
 199
 200 /* Determine whether CHREC is an affine evolution function or not.  */
 201
 202 static inline bool
 203 evolution_function_is_affine_p (const_tree chrec)
 204 {
 205   return chrec
 206     && TREE_CODE (chrec) == POLYNOMIAL_CHREC
 207     && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
 208                                           CHREC_VARIABLE (chrec))
 209     && (TREE_CODE (CHREC_RIGHT (chrec)) != POLYNOMIAL_CHREC
 210         || evolution_function_is_affine_p (CHREC_RIGHT (chrec)));
 211 }
 212
 213 /* Determines whether EXPR does not contains chrec expressions.  */
 214
 215 static inline bool
 216 tree_does_not_contain_chrecs (const_tree expr)
 217 {
 218   return !tree_contains_chrecs (expr, NULL);
 219 }
 220
 221 /* Returns the type of the chrec.  */
 222
 223 static inline tree
 224 chrec_type (const_tree chrec)
 225 {
 226   if (automatically_generated_chrec_p (chrec))
 227     return NULL_TREE;
 228
 229   return TREE_TYPE (chrec);
 230 }
 231
 232 static inline tree
 233 chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
 234 {
 235   switch (code)
 236     {
 237     case PLUS_EXPR:
 238       return chrec_fold_plus (type, op0, op1);
 239
 240     case MINUS_EXPR:
 241       return chrec_fold_minus (type, op0, op1);
 242
 243     case MULT_EXPR:
 244       return chrec_fold_multiply (type, op0, op1);
 245
 246     default:
 247       gcc_unreachable ();
 248     }
 249
 250 }
 251
 252 #endif  /* GCC_TREE_CHREC_H  */