gcc/tree-chrec.h

   1 /* Chains of recurrences.
   2    Copyright (C) 2003-2013 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_apply_map (tree, vec<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_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 extern bool evolution_function_right_is_integer_cst (const_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   STRIP_NOPS (chrec);
 118   scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
 119   *res = !tree_contains_chrecs (scev, NULL);
 120   return true;
 121 }
 122
 123 /* Build a polynomial chain of recurrence.  */
 124
 125 static inline tree
 126 build_polynomial_chrec (unsigned loop_num,
 127                         tree left,
 128                         tree right)
 129 {
 130   bool val;
 131
 132   if (left == chrec_dont_know
 133       || right == chrec_dont_know)
 134     return chrec_dont_know;
 135
 136   if (!no_evolution_in_loop_p (left, loop_num, &val)
 137       || !val)
 138     return chrec_dont_know;
 139
 140   /* Pointer types should occur only on the left hand side, i.e. in
 141      the base of the chrec, and not in the step.  */
 142   gcc_assert (!POINTER_TYPE_P (TREE_TYPE (right)));
 143
 144   /* Types of left and right sides of a chrec should be compatible.  */
 145   if (POINTER_TYPE_P (TREE_TYPE (left)))
 146     gcc_assert (ptrofftype_p (TREE_TYPE (right)));
 147   else
 148     gcc_assert (TREE_TYPE (left) == TREE_TYPE (right));
 149
 150   if (chrec_zerop (right))
 151     return left;
 152
 153   return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
 154                  build_int_cst (NULL_TREE, loop_num), left, right);
 155 }
 156
 157 /* Determines whether the expression CHREC is a constant.  */
 158
 159 static inline bool
 160 evolution_function_is_constant_p (const_tree chrec)
 161 {
 162   if (chrec == NULL_TREE)
 163     return false;
 164
 165   switch (TREE_CODE (chrec))
 166     {
 167     case INTEGER_CST:
 168     case REAL_CST:
 169       return true;
 170
 171     default:
 172       return false;
 173     }
 174 }
 175
 176 /* Determine whether CHREC is an affine evolution function in LOOPNUM.  */
 177
 178 static inline bool
 179 evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
 180 {
 181   if (chrec == NULL_TREE)
 182     return false;
 183
 184   switch (TREE_CODE (chrec))
 185     {
 186     case POLYNOMIAL_CHREC:
 187       if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
 188           && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
 189         return true;
 190       else
 191         return false;
 192
 193     default:
 194       return false;
 195     }
 196 }
 197
 198 /* Determine whether CHREC is an affine evolution function or not.  */
 199
 200 static inline bool
 201 evolution_function_is_affine_p (const_tree chrec)
 202 {
 203   return chrec
 204     && TREE_CODE (chrec) == POLYNOMIAL_CHREC
 205     && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
 206                                           CHREC_VARIABLE (chrec))
 207     && (TREE_CODE (CHREC_RIGHT (chrec)) != POLYNOMIAL_CHREC
 208         || evolution_function_is_affine_p (CHREC_RIGHT (chrec)));
 209 }
 210
 211 /* Determines whether EXPR does not contains chrec expressions.  */
 212
 213 static inline bool
 214 tree_does_not_contain_chrecs (const_tree expr)
 215 {
 216   return !tree_contains_chrecs (expr, NULL);
 217 }
 218
 219 /* Returns the type of the chrec.  */
 220
 221 static inline tree
 222 chrec_type (const_tree chrec)
 223 {
 224   if (automatically_generated_chrec_p (chrec))
 225     return NULL_TREE;
 226
 227   return TREE_TYPE (chrec);
 228 }
 229
 230 static inline tree
 231 chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
 232 {
 233   switch (code)
 234     {
 235     case PLUS_EXPR:
 236       return chrec_fold_plus (type, op0, op1);
 237
 238     case MINUS_EXPR:
 239       return chrec_fold_minus (type, op0, op1);
 240
 241     case MULT_EXPR:
 242       return chrec_fold_multiply (type, op0, op1);
 243
 244     default:
 245       gcc_unreachable ();
 246     }
 247
 248 }
 249
 250 #endif  /* GCC_TREE_CHREC_H  */