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b679b55b | 1 | /* IPA predicates. |
85ec4feb | 2 | Copyright (C) 2003-2018 Free Software Foundation, Inc. |
b679b55b JH |
3 | Contributed by Jan Hubicka |
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 | /* Representation of inline parameters that do depend on context function is | |
22 | inlined into (i.e. known constant values of function parameters. | |
23 | ||
24 | Conditions that are interesting for function body are collected into CONDS | |
25 | vector. They are of simple for function_param OP VAL, where VAL is | |
26 | IPA invariant. The conditions are then referred by predicates. */ | |
27 | ||
28 | struct GTY(()) condition | |
29 | { | |
30 | /* If agg_contents is set, this is the offset from which the used data was | |
31 | loaded. */ | |
32 | HOST_WIDE_INT offset; | |
33 | /* Size of the access reading the data (or the PARM_DECL SSA_NAME). */ | |
34 | HOST_WIDE_INT size; | |
35 | tree val; | |
36 | int operand_num; | |
37 | ENUM_BITFIELD(tree_code) code : 16; | |
38 | /* Set if the used data were loaded from an aggregate parameter or from | |
39 | data received by reference. */ | |
40 | unsigned agg_contents : 1; | |
41 | /* If agg_contents is set, this differentiates between loads from data | |
42 | passed by reference and by value. */ | |
43 | unsigned by_ref : 1; | |
44 | }; | |
45 | ||
46 | /* Information kept about parameter of call site. */ | |
47 | struct inline_param_summary | |
48 | { | |
49 | /* REG_BR_PROB_BASE based probability that parameter will change in between | |
50 | two invocation of the calls. | |
51 | I.e. loop invariant parameters | |
52 | REG_BR_PROB_BASE/estimated_iterations and regular | |
53 | parameters REG_BR_PROB_BASE. | |
54 | ||
55 | Value 0 is reserved for compile time invariants. */ | |
56 | int change_prob; | |
57 | }; | |
58 | ||
59 | typedef vec<condition, va_gc> *conditions; | |
60 | ||
61 | /* Predicates are used to repesent function parameters (such as runtime) | |
62 | which depend on a context function is called in. | |
63 | ||
64 | Predicates are logical formulas in conjunctive-disjunctive form consisting | |
65 | of clauses which are bitmaps specifying a set of condition that must | |
66 | be true for a clause to be satisfied. Physically they are represented as | |
67 | array of clauses terminated by 0. | |
68 | ||
69 | In order to make predicate (possibly) true, all of its clauses must | |
70 | be (possibly) true. To make clause (possibly) true, one of conditions | |
71 | it mentions must be (possibly) true. | |
72 | ||
73 | There are fixed bounds on number of clauses and conditions and all the | |
74 | manipulation functions are conservative in positive direction. I.e. we | |
75 | may lose precision by thinking that predicate may be true even when it | |
76 | is not. */ | |
77 | ||
78 | typedef uint32_t clause_t; | |
79 | class predicate | |
80 | { | |
81 | public: | |
82 | enum predicate_conditions | |
83 | { | |
84 | false_condition = 0, | |
85 | not_inlined_condition = 1, | |
86 | first_dynamic_condition = 2 | |
87 | }; | |
88 | ||
89 | /* Maximal number of conditions predicate can reffer to. This is limited | |
90 | by using clause_t to be 32bit. */ | |
91 | static const int num_conditions = 32; | |
92 | ||
93 | /* Special condition code we use to represent test that operand is compile | |
94 | time constant. */ | |
95 | static const tree_code is_not_constant = ERROR_MARK; | |
96 | ||
97 | /* Special condition code we use to represent test that operand is not changed | |
98 | across invocation of the function. When operand IS_NOT_CONSTANT it is | |
99 | always CHANGED, however i.e. loop invariants can be NOT_CHANGED given | |
100 | percentage of executions even when they are not compile time constants. */ | |
101 | static const tree_code changed = IDENTIFIER_NODE; | |
102 | ||
103 | ||
104 | ||
105 | /* Initialize predicate either to true of false depending on P. */ | |
106 | inline predicate (bool p = true) | |
107 | { | |
108 | if (p) | |
109 | /* True predicate. */ | |
110 | m_clause[0] = 0; | |
111 | else | |
112 | /* False predicate. */ | |
113 | set_to_cond (false_condition); | |
114 | } | |
115 | ||
116 | /* Sanity check that we do not mix pointers to predicates with predicates. */ | |
117 | inline predicate (predicate *) | |
118 | { | |
119 | gcc_unreachable (); | |
120 | } | |
121 | ||
122 | /* Return predicate testing condition I. */ | |
123 | static inline predicate predicate_testing_cond (int i) | |
124 | { | |
125 | class predicate p; | |
126 | p.set_to_cond (i + first_dynamic_condition); | |
127 | return p; | |
128 | } | |
129 | ||
130 | /* Return predicate testing that function was not inlined. */ | |
131 | static predicate not_inlined (void) | |
132 | { | |
133 | class predicate p; | |
134 | p.set_to_cond (not_inlined_condition); | |
135 | return p; | |
136 | } | |
137 | ||
138 | /* Compute logical and of predicates. */ | |
139 | predicate & operator &= (const predicate &); | |
61890ff2 | 140 | inline predicate operator &(const predicate &p) const |
b679b55b JH |
141 | { |
142 | predicate ret = *this; | |
143 | ret &= p; | |
144 | return ret; | |
145 | } | |
146 | ||
147 | /* Compute logical or of predicates. This is not operator because | |
148 | extra parameter CONDITIONS is needed */ | |
149 | predicate or_with (conditions, const predicate &) const; | |
150 | ||
151 | /* Return true if predicates are known to be equal. */ | |
152 | inline bool operator==(const predicate &p2) const | |
153 | { | |
154 | int i; | |
155 | for (i = 0; m_clause[i]; i++) | |
156 | { | |
157 | gcc_checking_assert (i < max_clauses); | |
158 | gcc_checking_assert (m_clause[i] > m_clause[i + 1]); | |
159 | gcc_checking_assert (!p2.m_clause[i] | |
160 | || p2.m_clause[i] > p2.m_clause[i + 1]); | |
161 | if (m_clause[i] != p2.m_clause[i]) | |
162 | return false; | |
163 | } | |
164 | return !p2.m_clause[i]; | |
165 | } | |
166 | ||
167 | /* Return true if predicates are known to be true or false depending | |
168 | on COND. */ | |
169 | inline bool operator==(const bool cond) const | |
170 | { | |
171 | if (cond) | |
172 | return !m_clause[0]; | |
173 | if (m_clause[0] == (1 << false_condition)) | |
174 | { | |
175 | gcc_checking_assert (!m_clause[1] | |
176 | && m_clause[0] == 1 | |
177 | << false_condition); | |
178 | return true; | |
179 | } | |
180 | return false; | |
181 | } | |
182 | ||
183 | inline bool operator!=(const predicate &p2) const | |
184 | { | |
185 | return !(*this == p2); | |
186 | } | |
187 | ||
188 | inline bool operator!=(const bool cond) const | |
189 | { | |
190 | return !(*this == cond); | |
191 | } | |
192 | ||
193 | /* Evaluate if predicate is known to be false given the clause of possible | |
194 | truths. */ | |
195 | bool evaluate (clause_t) const; | |
196 | ||
197 | /* Estimate probability that predicate will be true in a given context. */ | |
198 | int probability (conditions, clause_t, vec<inline_param_summary>) const; | |
199 | ||
200 | /* Dump predicate to F. Output newline if nl. */ | |
201 | void dump (FILE *f, conditions, bool nl=true) const; | |
202 | void DEBUG_FUNCTION debug (conditions) const; | |
203 | ||
204 | /* Return predicate equal to THIS after duplication. */ | |
205 | predicate remap_after_duplication (clause_t); | |
206 | ||
207 | /* Return predicate equal to THIS after inlining. */ | |
0bceb671 JH |
208 | predicate remap_after_inlining (struct ipa_fn_summary *, |
209 | struct ipa_fn_summary *, | |
b679b55b JH |
210 | vec<int>, vec<int>, clause_t, const predicate &); |
211 | ||
212 | void stream_in (struct lto_input_block *); | |
213 | void stream_out (struct output_block *); | |
214 | ||
215 | private: | |
216 | static const int max_clauses = 8; | |
217 | clause_t m_clause[max_clauses + 1]; | |
218 | ||
219 | /* Initialize predicate to one testing single condition number COND. */ | |
220 | inline void set_to_cond (int cond) | |
221 | { | |
222 | m_clause[0] = 1 << cond; | |
223 | m_clause[1] = 0; | |
224 | } | |
225 | ||
226 | void add_clause (conditions conditions, clause_t); | |
227 | }; | |
228 | ||
229 | void dump_condition (FILE *f, conditions conditions, int cond); | |
0bceb671 | 230 | predicate add_condition (struct ipa_fn_summary *summary, int operand_num, |
b679b55b JH |
231 | HOST_WIDE_INT size, struct agg_position_info *aggpos, |
232 | enum tree_code code, tree val); |