gcc/tree-chrec.h

   1 /* Chains of recurrences.
   2    Copyright (C) 2003-2020 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 tree chrec_dont_know;
  30    extern tree chrec_known;
  31
  32    chrec_not_analyzed_yet is NULL_TREE and the others are defined
  33    in global_trees[].  */
  34
  35 /* After having added an automatically generated element, please
  36    include it in the following function.  */
  37
  38 static inline bool
  39 automatically_generated_chrec_p (const_tree chrec)
  40 {
  41   return (chrec == chrec_dont_know
  42           || chrec == chrec_known);
  43 }
  44
  45 /* The tree nodes aka. CHRECs.  */
  46
  47 static inline bool
  48 tree_is_chrec (const_tree expr)
  49 {
  50   if (TREE_CODE (expr) == POLYNOMIAL_CHREC
  51       || automatically_generated_chrec_p (expr))
  52     return true;
  53   else
  54     return false;
  55 }
  56
  57 \f
  58 enum ev_direction {EV_DIR_GROWS, EV_DIR_DECREASES, EV_DIR_UNKNOWN};
  59 enum ev_direction scev_direction (const_tree);
  60
  61 /* Chrec folding functions.  */
  62 extern tree chrec_fold_plus (tree, tree, tree);
  63 extern tree chrec_fold_minus (tree, tree, tree);
  64 extern tree chrec_fold_multiply (tree, tree, tree);
  65 extern tree chrec_convert (tree, tree, gimple *, bool = true, tree = NULL);
  66 extern tree chrec_convert_rhs (tree, tree, gimple *);
  67 extern tree chrec_convert_aggressive (tree, tree, bool *);
  68
  69 /* Operations.  */
  70 extern tree chrec_apply (unsigned, tree, tree);
  71 extern tree chrec_apply_map (tree, vec<tree> );
  72 extern tree chrec_replace_initial_condition (tree, tree);
  73 extern tree initial_condition (tree);
  74 extern tree initial_condition_in_loop_num (tree, unsigned);
  75 extern tree evolution_part_in_loop_num (tree, unsigned);
  76 extern tree hide_evolution_in_other_loops_than_loop (tree, unsigned);
  77 extern tree reset_evolution_in_loop (unsigned, tree, tree);
  78 extern tree chrec_merge (tree, tree);
  79 extern void for_each_scev_op (tree *, bool (*) (tree *, void *), void *);
  80 extern bool convert_affine_scev (class loop *, tree, tree *, tree *, gimple *,
  81                                  bool, tree = NULL);
  82
  83 /* Observers.  */
  84 extern bool eq_evolutions_p (const_tree, const_tree);
  85 extern bool is_multivariate_chrec (const_tree);
  86 extern bool chrec_contains_symbols (const_tree, class loop * = NULL);
  87 extern bool chrec_contains_symbols_defined_in_loop (const_tree, unsigned);
  88 extern bool chrec_contains_undetermined (const_tree);
  89 extern bool tree_contains_chrecs (const_tree, int *);
  90 extern bool evolution_function_is_affine_multivariate_p (const_tree, int);
  91 extern bool evolution_function_is_univariate_p (const_tree, int = 0);
  92 extern unsigned nb_vars_in_chrec (tree);
  93 extern bool evolution_function_is_invariant_p (tree, int);
  94 extern bool scev_is_linear_expression (tree);
  95 extern bool evolution_function_right_is_integer_cst (const_tree);
  96
  97 /* Determines whether CHREC is equal to zero.  */
  98
  99 static inline bool
 100 chrec_zerop (const_tree chrec)
 101 {
 102   if (chrec == NULL_TREE)
 103     return false;
 104
 105   if (TREE_CODE (chrec) == INTEGER_CST)
 106     return integer_zerop (chrec);
 107
 108   return false;
 109 }
 110
 111 /* Determines whether CHREC is a loop invariant with respect to LOOP_NUM.
 112    Set the result in RES and return true when the property can be computed.  */
 113
 114 static inline bool
 115 no_evolution_in_loop_p (tree chrec, unsigned loop_num, bool *res)
 116 {
 117   tree scev;
 118
 119   if (chrec == chrec_not_analyzed_yet
 120       || chrec == chrec_dont_know
 121       || chrec_contains_symbols_defined_in_loop (chrec, loop_num))
 122     return false;
 123
 124   STRIP_NOPS (chrec);
 125   scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
 126   *res = !tree_contains_chrecs (scev, NULL);
 127   return true;
 128 }
 129
 130 /* Build a polynomial chain of recurrence.  */
 131
 132 static inline tree
 133 build_polynomial_chrec (unsigned loop_num,
 134                         tree left,
 135                         tree right)
 136 {
 137   bool val;
 138
 139   if (left == chrec_dont_know
 140       || right == chrec_dont_know)
 141     return chrec_dont_know;
 142
 143   if (!no_evolution_in_loop_p (left, loop_num, &val)
 144       || !val)
 145     return chrec_dont_know;
 146
 147   /* Types of left and right sides of a chrec should be compatible, but
 148      pointer CHRECs are special in that the evolution is of ptroff type.  */
 149   if (POINTER_TYPE_P (TREE_TYPE (left)))
 150     gcc_checking_assert (ptrofftype_p (TREE_TYPE (right)));
 151   else
 152     {
 153       /* Pointer types should occur only on the left hand side, i.e. in
 154          the base of the chrec, and not in the step.  */
 155       gcc_checking_assert (!POINTER_TYPE_P (TREE_TYPE (right))
 156                            && types_compatible_p (TREE_TYPE (left),
 157                                                   TREE_TYPE (right)));
 158     }
 159
 160   if (chrec_zerop (right))
 161     return left;
 162
 163   tree chrec = build2 (POLYNOMIAL_CHREC, TREE_TYPE (left), left, right);
 164   CHREC_VARIABLE (chrec) = loop_num;
 165   return chrec;
 166 }
 167
 168 /* Determines whether the expression CHREC is a constant.  */
 169
 170 static inline bool
 171 evolution_function_is_constant_p (const_tree chrec)
 172 {
 173   if (chrec == NULL_TREE)
 174     return false;
 175
 176   return is_gimple_min_invariant (chrec);
 177 }
 178
 179 /* Determine whether CHREC is an affine evolution function in LOOPNUM.  */
 180
 181 static inline bool
 182 evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
 183 {
 184   if (chrec == NULL_TREE)
 185     return false;
 186
 187   switch (TREE_CODE (chrec))
 188     {
 189     case POLYNOMIAL_CHREC:
 190       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
 191           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
 192         return true;
 193       else
 194         return false;
 195
 196     default:
 197       return false;
 198     }
 199 }
 200
 201 /* Determine whether CHREC is an affine evolution function or not.  */
 202
 203 static inline bool
 204 evolution_function_is_affine_p (const_tree chrec)
 205 {
 206   return chrec
 207     && TREE_CODE (chrec) == POLYNOMIAL_CHREC
 208     && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
 209                                           CHREC_VARIABLE (chrec))
 210     && (TREE_CODE (CHREC_RIGHT (chrec)) != POLYNOMIAL_CHREC
 211         || evolution_function_is_affine_p (CHREC_RIGHT (chrec)));
 212 }
 213
 214 /* Determines whether EXPR does not contains chrec expressions.  */
 215
 216 static inline bool
 217 tree_does_not_contain_chrecs (const_tree expr)
 218 {
 219   return !tree_contains_chrecs (expr, NULL);
 220 }
 221
 222 /* Returns the type of the chrec.  */
 223
 224 static inline tree
 225 chrec_type (const_tree chrec)
 226 {
 227   if (automatically_generated_chrec_p (chrec))
 228     return NULL_TREE;
 229
 230   return TREE_TYPE (chrec);
 231 }
 232
 233 static inline tree
 234 chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
 235 {
 236   switch (code)
 237     {
 238     case PLUS_EXPR:
 239       return chrec_fold_plus (type, op0, op1);
 240
 241     case MINUS_EXPR:
 242       return chrec_fold_minus (type, op0, op1);
 243
 244     case MULT_EXPR:
 245       return chrec_fold_multiply (type, op0, op1);
 246
 247     default:
 248       gcc_unreachable ();
 249     }
 250
 251 }
 252
 253 #endif  /* GCC_TREE_CHREC_H  */