1 /* Chains of recurrences.
2 Copyright (C) 2003, 2004, 2005, 2006 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 2, 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 COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
20 02110-1301, USA. */
21
22 #ifndef GCC_TREE_CHREC_H
23 #define GCC_TREE_CHREC_H
24
25 /* Accessors for the chains of recurrences. */
26 #define CHREC_VAR(NODE) TREE_OPERAND (NODE, 0)
27 #define CHREC_LEFT(NODE) TREE_OPERAND (NODE, 1)
28 #define CHREC_RIGHT(NODE) TREE_OPERAND (NODE, 2)
29 #define CHREC_VARIABLE(NODE) TREE_INT_CST_LOW (CHREC_VAR (NODE))
30
31
32
33 /* The following trees are unique elements. Thus the comparison of another
34 element to these elements should be done on the pointer to these trees,
35 and not on their value. */
36
37 extern tree chrec_not_analyzed_yet;
38 extern GTY(()) tree chrec_dont_know;
39 extern GTY(()) tree chrec_known;
40
41 /* After having added an automatically generated element, please
42 include it in the following function. */
43
44 static inline bool
automatically_generated_chrec_p(tree chrec)45 automatically_generated_chrec_p (tree chrec)
46 {
47 return (chrec == chrec_not_analyzed_yet
48 || chrec == chrec_dont_know
49 || chrec == chrec_known);
50 }
51
52 /* The tree nodes aka. CHRECs. */
53
54 static inline bool
tree_is_chrec(tree expr)55 tree_is_chrec (tree expr)
56 {
57 if (TREE_CODE (expr) == POLYNOMIAL_CHREC
58 || automatically_generated_chrec_p (expr))
59 return true;
60 else
61 return false;
62 }
63
64
65
66 /* Chrec folding functions. */
67 extern tree chrec_fold_plus (tree, tree, tree);
68 extern tree chrec_fold_minus (tree, tree, tree);
69 extern tree chrec_fold_multiply (tree, tree, tree);
70 extern tree chrec_convert (tree, tree, tree);
71 extern tree chrec_convert_aggressive (tree, tree);
72
73 /* Operations. */
74 extern tree chrec_apply (unsigned, tree, tree);
75 extern tree chrec_replace_initial_condition (tree, tree);
76 extern tree initial_condition (tree);
77 extern tree initial_condition_in_loop_num (tree, unsigned);
78 extern tree evolution_part_in_loop_num (tree, unsigned);
79 extern tree hide_evolution_in_other_loops_than_loop (tree, unsigned);
80 extern tree reset_evolution_in_loop (unsigned, tree, tree);
81 extern tree chrec_merge (tree, tree);
82
83 /* Observers. */
84 extern bool eq_evolutions_p (tree, tree);
85 extern bool is_multivariate_chrec (tree);
86 extern bool chrec_is_positive (tree, bool *);
87 extern bool chrec_contains_symbols (tree);
88 extern bool chrec_contains_symbols_defined_in_loop (tree, unsigned);
89 extern bool chrec_contains_undetermined (tree);
90 extern bool tree_contains_chrecs (tree, int *);
91 extern bool evolution_function_is_affine_multivariate_p (tree);
92 extern bool evolution_function_is_univariate_p (tree);
93 extern unsigned nb_vars_in_chrec (tree);
94
95
96
97 /* Build a polynomial chain of recurrence. */
98
99 static inline tree
build_polynomial_chrec(unsigned loop_num,tree left,tree right)100 build_polynomial_chrec (unsigned loop_num,
101 tree left,
102 tree right)
103 {
104 if (left == chrec_dont_know
105 || right == chrec_dont_know)
106 return chrec_dont_know;
107
108 gcc_assert (TREE_TYPE (left) == TREE_TYPE (right));
109
110 return build3 (POLYNOMIAL_CHREC, TREE_TYPE (left),
111 build_int_cst (NULL_TREE, loop_num), left, right);
112 }
113
114
115
116 /* Observers. */
117
118 /* Determines whether CHREC is equal to zero. */
119
120 static inline bool
chrec_zerop(tree chrec)121 chrec_zerop (tree chrec)
122 {
123 if (chrec == NULL_TREE)
124 return false;
125
126 if (TREE_CODE (chrec) == INTEGER_CST)
127 return integer_zerop (chrec);
128
129 return false;
130 }
131
132 /* Determines whether the expression CHREC is a constant. */
133
134 static inline bool
evolution_function_is_constant_p(tree chrec)135 evolution_function_is_constant_p (tree chrec)
136 {
137 if (chrec == NULL_TREE)
138 return false;
139
140 switch (TREE_CODE (chrec))
141 {
142 case INTEGER_CST:
143 case REAL_CST:
144 return true;
145
146 default:
147 return false;
148 }
149 }
150
151 extern bool evolution_function_is_invariant_p (tree, int);
152 /* Determine whether the given tree is an affine evolution function or not. */
153
154 static inline bool
evolution_function_is_affine_p(tree chrec)155 evolution_function_is_affine_p (tree chrec)
156 {
157 if (chrec == NULL_TREE)
158 return false;
159
160 switch (TREE_CODE (chrec))
161 {
162 case POLYNOMIAL_CHREC:
163 if (evolution_function_is_invariant_p (CHREC_LEFT (chrec),
164 CHREC_VARIABLE (chrec))
165 && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
166 CHREC_VARIABLE (chrec)))
167 return true;
168 else
169 return false;
170
171 default:
172 return false;
173 }
174 }
175
176 /* Determine whether the given tree is an affine or constant evolution
177 function. */
178
179 static inline bool
evolution_function_is_affine_or_constant_p(tree chrec)180 evolution_function_is_affine_or_constant_p (tree chrec)
181 {
182 return evolution_function_is_affine_p (chrec)
183 || evolution_function_is_constant_p (chrec);
184 }
185
186 /* Determines whether EXPR does not contains chrec expressions. */
187
188 static inline bool
tree_does_not_contain_chrecs(tree expr)189 tree_does_not_contain_chrecs (tree expr)
190 {
191 return !tree_contains_chrecs (expr, NULL);
192 }
193
194 /* Determines whether CHREC is a loop invariant with respect to LOOP_NUM.
195 Set the result in RES and return true when the property can be computed. */
196
197 static inline bool
no_evolution_in_loop_p(tree chrec,unsigned loop_num,bool * res)198 no_evolution_in_loop_p (tree chrec, unsigned loop_num, bool *res)
199 {
200 tree scev;
201
202 if (chrec == chrec_not_analyzed_yet
203 || chrec == chrec_dont_know
204 || chrec_contains_symbols_defined_in_loop (chrec, loop_num))
205 return false;
206
207 scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
208 *res = !tree_is_chrec (scev);
209 return true;
210 }
211
212 /* Returns the type of the chrec. */
213
214 static inline tree
chrec_type(tree chrec)215 chrec_type (tree chrec)
216 {
217 if (automatically_generated_chrec_p (chrec))
218 return NULL_TREE;
219
220 return TREE_TYPE (chrec);
221 }
222
223
224 #endif /* GCC_TREE_CHREC_H */
225