1/* Chains of recurrences.
2 Copyright (C) 2003-2017 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 *, bool = true, tree = NULL);
63extern tree chrec_convert_rhs (tree, tree, gimple *);
64extern tree chrec_convert_aggressive (tree, tree, bool *);
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, tree = NULL);
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 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
167static inline bool
168evolution_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
180static inline bool
181evolution_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
202static inline bool
203evolution_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
215static inline bool
216tree_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
223static inline tree
224chrec_type (const_tree chrec)
225{
226 if (automatically_generated_chrec_p (chrec))
227 return NULL_TREE;
228
229 return TREE_TYPE (chrec);
230}
231
232static inline tree
233chrec_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 */
253