1/* Chains of recurrences.
2 Copyright (C) 2003-2023 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
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
38inline bool
39automatically_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
47inline bool
48tree_is_chrec (const_tree expr)
49{
50 if (TREE_CODE (expr) == POLYNOMIAL_CHREC
51 || automatically_generated_chrec_p (chrec: expr))
52 return true;
53 else
54 return false;
55}
56
57
58enum ev_direction {EV_DIR_GROWS, EV_DIR_DECREASES, EV_DIR_UNKNOWN};
59enum ev_direction scev_direction (const_tree);
60
61/* Chrec folding functions. */
62extern tree chrec_fold_plus (tree, tree, tree);
63extern tree chrec_fold_minus (tree, tree, tree);
64extern tree chrec_fold_multiply (tree, tree, tree);
65extern tree chrec_convert (tree, tree, gimple *, bool = true, tree = NULL);
66extern tree chrec_convert_rhs (tree, tree, gimple *);
67extern tree chrec_convert_aggressive (tree, tree, bool *);
68
69/* Operations. */
70extern tree chrec_apply (unsigned, tree, tree);
71extern tree chrec_apply_map (tree, vec<tree> );
72extern tree chrec_replace_initial_condition (tree, tree);
73extern tree initial_condition (tree);
74extern tree initial_condition_in_loop_num (tree, unsigned);
75extern tree evolution_part_in_loop_num (tree, unsigned);
76extern tree hide_evolution_in_other_loops_than_loop (tree, unsigned);
77extern tree reset_evolution_in_loop (unsigned, tree, tree);
78extern tree chrec_merge (tree, tree);
79extern void for_each_scev_op (tree *, bool (*) (tree *, void *), void *);
80extern bool convert_affine_scev (class loop *, tree, tree *, tree *, gimple *,
81 bool, tree = NULL);
82
83/* Observers. */
84extern bool eq_evolutions_p (const_tree, const_tree);
85extern bool is_multivariate_chrec (const_tree);
86extern bool chrec_contains_symbols (const_tree, class loop * = NULL);
87extern bool chrec_contains_symbols_defined_in_loop (const_tree, unsigned);
88extern bool chrec_contains_undetermined (const_tree);
89extern bool tree_contains_chrecs (const_tree, int *);
90extern bool evolution_function_is_affine_multivariate_p (const_tree, int);
91extern bool evolution_function_is_univariate_p (const_tree, int = 0);
92extern unsigned nb_vars_in_chrec (tree);
93extern bool evolution_function_is_invariant_p (tree, int);
94extern bool scev_is_linear_expression (tree);
95extern bool evolution_function_right_is_integer_cst (const_tree);
96
97/* Determines whether CHREC is equal to zero. */
98
99inline bool
100chrec_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
114inline bool
115no_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
132inline tree
133build_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 (chrec: left, loop_num, res: &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 (chrec: 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
170inline bool
171evolution_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
181inline bool
182evolution_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
203inline bool
204evolution_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
216inline bool
217tree_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
224inline tree
225chrec_type (const_tree chrec)
226{
227 if (automatically_generated_chrec_p (chrec))
228 return NULL_TREE;
229
230 return TREE_TYPE (chrec);
231}
232
233inline tree
234chrec_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 */
254

source code of gcc/tree-chrec.h