1/* Chains of recurrences.
2   Copyright (C) 2003-2015 Free Software Foundation, Inc.
3   Contributed by Sebastian Pop <pop@cri.ensmp.fr>
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along 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
28extern tree chrec_not_analyzed_yet;
29extern GTY(()) tree chrec_dont_know;
30extern GTY(()) tree chrec_known;
31
32/* After having added an automatically generated element, please
33   include it in the following function.  */
34
35static inline bool
36automatically_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
44static inline bool
45tree_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
55enum ev_direction {EV_DIR_GROWS, EV_DIR_DECREASES, EV_DIR_UNKNOWN};
56enum ev_direction scev_direction (const_tree);
57
58/* Chrec folding functions.  */
59extern tree chrec_fold_plus (tree, tree, tree);
60extern tree chrec_fold_minus (tree, tree, tree);
61extern tree chrec_fold_multiply (tree, tree, tree);
62extern tree chrec_convert (tree, tree, gimple);
63extern tree chrec_convert_rhs (tree, tree, gimple);
64extern tree chrec_convert_aggressive (tree, tree);
65
66/* Operations.  */
67extern tree chrec_apply (unsigned, tree, tree);
68extern tree chrec_apply_map (tree, vec<tree> );
69extern tree chrec_replace_initial_condition (tree, tree);
70extern tree initial_condition (tree);
71extern tree initial_condition_in_loop_num (tree, unsigned);
72extern tree evolution_part_in_loop_num (tree, unsigned);
73extern tree hide_evolution_in_other_loops_than_loop (tree, unsigned);
74extern tree reset_evolution_in_loop (unsigned, tree, tree);
75extern tree chrec_merge (tree, tree);
76extern void for_each_scev_op (tree *, bool (*) (tree *, void *), void *);
77extern bool convert_affine_scev (struct loop *, tree, tree *, tree *, gimple,
78				 bool);
79
80/* Observers.  */
81extern bool eq_evolutions_p (const_tree, const_tree);
82extern bool is_multivariate_chrec (const_tree);
83extern bool chrec_contains_symbols (const_tree);
84extern bool chrec_contains_symbols_defined_in_loop (const_tree, unsigned);
85extern bool chrec_contains_undetermined (const_tree);
86extern bool tree_contains_chrecs (const_tree, int *);
87extern bool evolution_function_is_affine_multivariate_p (const_tree, int);
88extern bool evolution_function_is_univariate_p (const_tree);
89extern unsigned nb_vars_in_chrec (tree);
90extern bool evolution_function_is_invariant_p (tree, int);
91extern bool scev_is_linear_expression (tree);
92extern bool evolution_function_right_is_integer_cst (const_tree);
93
94/* Determines whether CHREC is equal to zero.  */
95
96static inline bool
97chrec_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
111static inline bool
112no_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
129static inline tree
130build_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  return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
161		 build_int_cst (NULL_TREE, loop_num), left, right);
162}
163
164/* Determines whether the expression CHREC is a constant.  */
165
166static inline bool
167evolution_function_is_constant_p (const_tree chrec)
168{
169  if (chrec == NULL_TREE)
170    return false;
171
172  switch (TREE_CODE (chrec))
173    {
174    case INTEGER_CST:
175    case REAL_CST:
176      return true;
177
178    default:
179      return false;
180    }
181}
182
183/* Determine whether CHREC is an affine evolution function in LOOPNUM.  */
184
185static inline bool
186evolution_function_is_affine_in_loop (const_tree chrec, int loopnum)
187{
188  if (chrec == NULL_TREE)
189    return false;
190
191  switch (TREE_CODE (chrec))
192    {
193    case POLYNOMIAL_CHREC:
194      if (evolution_function_is_invariant_p (CHREC_LEFT (chrec), loopnum)
195	  && evolution_function_is_invariant_p (CHREC_RIGHT (chrec), loopnum))
196	return true;
197      else
198	return false;
199
200    default:
201      return false;
202    }
203}
204
205/* Determine whether CHREC is an affine evolution function or not.  */
206
207static inline bool
208evolution_function_is_affine_p (const_tree chrec)
209{
210  return chrec
211    && TREE_CODE (chrec) == POLYNOMIAL_CHREC
212    && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
213					  CHREC_VARIABLE (chrec))
214    && (TREE_CODE (CHREC_RIGHT (chrec)) != POLYNOMIAL_CHREC
215	|| evolution_function_is_affine_p (CHREC_RIGHT (chrec)));
216}
217
218/* Determines whether EXPR does not contains chrec expressions.  */
219
220static inline bool
221tree_does_not_contain_chrecs (const_tree expr)
222{
223  return !tree_contains_chrecs (expr, NULL);
224}
225
226/* Returns the type of the chrec.  */
227
228static inline tree
229chrec_type (const_tree chrec)
230{
231  if (automatically_generated_chrec_p (chrec))
232    return NULL_TREE;
233
234  return TREE_TYPE (chrec);
235}
236
237static inline tree
238chrec_fold_op (enum tree_code code, tree type, tree op0, tree op1)
239{
240  switch (code)
241    {
242    case PLUS_EXPR:
243      return chrec_fold_plus (type, op0, op1);
244
245    case MINUS_EXPR:
246      return chrec_fold_minus (type, op0, op1);
247
248    case MULT_EXPR:
249      return chrec_fold_multiply (type, op0, op1);
250
251    default:
252      gcc_unreachable ();
253    }
254
255}
256
257#endif  /* GCC_TREE_CHREC_H  */
258