1 /* Chains of recurrences.
2 Copyright (C) 2003-2023 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 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 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
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 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 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 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 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 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 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 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 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 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 */