1 /* Inlining decision heuristics.
2 Copyright (C) 2003-2016 Free Software Foundation, Inc.
3 Contributed by Jan Hubicka
5 This file is part of GCC.
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
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
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/>. */
21 #ifndef GCC_IPA_INLINE_H
22 #define GCC_IPA_INLINE_H
25 /* Representation of inline parameters that do depend on context function is
26 inlined into (i.e. known constant values of function parameters.
28 Conditions that are interesting for function body are collected into CONDS
29 vector. They are of simple for function_param OP VAL, where VAL is
30 IPA invariant. The conditions are then referred by predicates. */
32 struct GTY(()) condition
34 /* If agg_contents is set, this is the offset from which the used data was
37 /* Size of the access reading the data (or the PARM_DECL SSA_NAME). */
41 ENUM_BITFIELD(tree_code) code : 16;
42 /* Set if the used data were loaded from an aggregate parameter or from
43 data received by reference. */
44 unsigned agg_contents : 1;
45 /* If agg_contents is set, this differentiates between loads from data
46 passed by reference and by value. */
50 /* Inline hints are reasons why inline heuristics should preffer inlining given
51 function. They are represtented as bitmap of the following values. */
52 enum inline_hints_vals {
53 /* When inlining turns indirect call into a direct call,
54 it is good idea to do so. */
55 INLINE_HINT_indirect_call = 1,
56 /* Inlining may make loop iterations or loop stride known. It is good idea
57 to do so because it enables loop optimizatoins. */
58 INLINE_HINT_loop_iterations = 2,
59 INLINE_HINT_loop_stride = 4,
60 /* Inlining within same strongly connected component of callgraph is often
61 a loss due to increased stack frame usage and prologue setup costs. */
62 INLINE_HINT_same_scc = 8,
63 /* Inlining functions in strongly connected component is not such a great
65 INLINE_HINT_in_scc = 16,
66 /* If function is declared inline by user, it may be good idea to inline
68 INLINE_HINT_declared_inline = 32,
69 /* Programs are usually still organized for non-LTO compilation and thus
70 if functions are in different modules, inlining may not be so important.
72 INLINE_HINT_cross_module = 64,
73 /* If array indexes of loads/stores become known there may be room for
74 further optimization. */
75 INLINE_HINT_array_index = 128,
76 /* We know that the callee is hot by profile. */
77 INLINE_HINT_known_hot = 256
79 typedef int inline_hints;
82 typedef vec<condition, va_gc> *conditions;
84 /* Representation of predicates i.e. formulas using conditions defined
85 above. Predicates are simple logical formulas in conjunctive-disjunctive
88 Predicate is array of clauses terminated by 0. Every clause must be true
89 in order to make predicate true.
90 Clauses are represented as bitmaps of conditions. One of conditions
91 must be true in order for clause to be true. */
94 typedef unsigned int clause_t;
95 struct GTY(()) predicate
97 clause_t clause[MAX_CLAUSES + 1];
100 /* Represnetation of function body size and time depending on the inline
101 context. We keep simple array of record, every containing of predicate
102 and time/size to account.
104 We keep values scaled up, so fractional sizes and times can be
106 #define INLINE_SIZE_SCALE 2
107 #define INLINE_TIME_SCALE (CGRAPH_FREQ_BASE * 2)
108 struct GTY(()) size_time_entry
110 struct predicate predicate;
115 /* Function inlining information. */
116 struct GTY(()) inline_summary
118 /* Information about the function body itself. */
120 /* Estimated stack frame consumption by the function. */
121 HOST_WIDE_INT estimated_self_stack_size;
122 /* Size of the function body. */
124 /* Time of the function body. */
126 /* Minimal size increase after inlining. */
129 /* False when there something makes inlining impossible (such as va_arg). */
130 unsigned inlinable : 1;
131 /* True when function contains cilk spawn (and thus we can not inline
133 unsigned contains_cilk_spawn : 1;
134 /* True wen there is only one caller of the function before small function
136 unsigned int single_caller : 1;
138 /* Information about function that will result after applying all the
139 inline decisions present in the callgraph. Generally kept up to
140 date only for functions that are not inline clones. */
142 /* Estimated stack frame consumption by the function. */
143 HOST_WIDE_INT estimated_stack_size;
144 /* Expected offset of the stack frame of inlined function. */
145 HOST_WIDE_INT stack_frame_offset;
146 /* Estimated size of the function after inlining. */
150 /* Conditional size/time information. The summaries are being
151 merged during inlining. */
153 vec<size_time_entry, va_gc> *entry;
155 /* Predicate on when some loop in the function becomes to have known
157 struct predicate * GTY((skip)) loop_iterations;
158 /* Predicate on when some loop in the function becomes to have known
160 struct predicate * GTY((skip)) loop_stride;
161 /* Predicate on when some array indexes become constants. */
162 struct predicate * GTY((skip)) array_index;
163 /* Estimated growth for inlining all copies of the function before start
164 of small functions inlining.
165 This value will get out of date as the callers are duplicated, but
166 using up-to-date value in the badness metric mean a lot of extra
169 /* Number of SCC on the beginning of inlining process. */
173 class GTY((user)) inline_summary_t: public function_summary <inline_summary *>
176 inline_summary_t (symbol_table *symtab, bool ggc):
177 function_summary <inline_summary *> (symtab, ggc) {}
179 static inline_summary_t *create_ggc (symbol_table *symtab)
181 struct inline_summary_t *summary = new (ggc_cleared_alloc <inline_summary_t> ())
182 inline_summary_t(symtab, true);
183 summary->disable_insertion_hook ();
188 virtual void insert (cgraph_node *, inline_summary *);
189 virtual void remove (cgraph_node *node, inline_summary *);
190 virtual void duplicate (cgraph_node *src, cgraph_node *dst,
191 inline_summary *src_data, inline_summary *dst_data);
194 extern GTY(()) function_summary <inline_summary *> *inline_summaries;
196 /* Information kept about parameter of call site. */
197 struct inline_param_summary
199 /* REG_BR_PROB_BASE based probability that parameter will change in between
200 two invocation of the calls.
201 I.e. loop invariant parameters
202 REG_BR_PROB_BASE/estimated_iterations and regular
203 parameters REG_BR_PROB_BASE.
205 Value 0 is reserved for compile time invariants. */
209 /* Information kept about callgraph edges. */
210 struct inline_edge_summary
212 /* Estimated size and time of the call statement. */
215 /* Depth of loop nest, 0 means no nesting. */
216 unsigned short int loop_depth;
217 struct predicate *predicate;
218 /* Array indexed by parameters.
219 0 means that parameter change all the time, REG_BR_PROB_BASE means
220 that parameter is constant. */
221 vec<inline_param_summary> param;
224 /* Need a typedef for inline_edge_summary because of inline function
225 'inline_edge_summary' below. */
226 typedef struct inline_edge_summary inline_edge_summary_t;
227 extern vec<inline_edge_summary_t> inline_edge_summary_vec;
229 struct edge_growth_cache_entry
235 extern vec<edge_growth_cache_entry> edge_growth_cache;
237 /* In ipa-inline-analysis.c */
238 void debug_inline_summary (struct cgraph_node *);
239 void dump_inline_summaries (FILE *f);
240 void dump_inline_summary (FILE *f, struct cgraph_node *node);
241 void dump_inline_hints (FILE *f, inline_hints);
242 void inline_generate_summary (void);
243 void inline_read_summary (void);
244 void inline_write_summary (void);
245 void inline_free_summary (void);
246 void inline_analyze_function (struct cgraph_node *node);
247 void initialize_inline_failed (struct cgraph_edge *);
248 int estimate_time_after_inlining (struct cgraph_node *, struct cgraph_edge *);
249 int estimate_size_after_inlining (struct cgraph_node *, struct cgraph_edge *);
250 void estimate_ipcp_clone_size_and_time (struct cgraph_node *,
252 vec<ipa_polymorphic_call_context>,
253 vec<ipa_agg_jump_function_p>,
254 int *, int *, inline_hints *);
255 int estimate_growth (struct cgraph_node *);
256 bool growth_likely_positive (struct cgraph_node *, int);
257 void inline_merge_summary (struct cgraph_edge *edge);
258 void inline_update_overall_summary (struct cgraph_node *node);
259 int do_estimate_edge_size (struct cgraph_edge *edge);
260 int do_estimate_edge_time (struct cgraph_edge *edge);
261 inline_hints do_estimate_edge_hints (struct cgraph_edge *edge);
262 void initialize_growth_caches (void);
263 void free_growth_caches (void);
264 void compute_inline_parameters (struct cgraph_node *, bool);
265 bool speculation_useful_p (struct cgraph_edge *e, bool anticipate_inlining);
266 unsigned int early_inliner (function *fun);
267 bool inline_account_function_p (struct cgraph_node *node);
270 /* In ipa-inline-transform.c */
271 bool inline_call (struct cgraph_edge *, bool, vec<cgraph_edge *> *, int *, bool,
272 bool *callee_removed = NULL);
273 unsigned int inline_transform (struct cgraph_node *);
274 void clone_inlined_nodes (struct cgraph_edge *e, bool, bool, int *,
277 extern int ncalls_inlined;
278 extern int nfunctions_inlined;
280 static inline struct inline_edge_summary *
281 inline_edge_summary (struct cgraph_edge *edge)
283 return &inline_edge_summary_vec[edge->uid];
287 /* Return estimated size of the inline sequence of EDGE. */
290 estimate_edge_size (struct cgraph_edge *edge)
293 if ((int)edge_growth_cache.length () <= edge->uid
294 || !(ret = edge_growth_cache[edge->uid].size))
295 return do_estimate_edge_size (edge);
296 return ret - (ret > 0);
299 /* Return estimated callee growth after inlining EDGE. */
302 estimate_edge_growth (struct cgraph_edge *edge)
304 gcc_checking_assert (inline_edge_summary (edge)->call_stmt_size
305 || !edge->callee->analyzed);
306 return (estimate_edge_size (edge)
307 - inline_edge_summary (edge)->call_stmt_size);
310 /* Return estimated callee runtime increase after inlning
314 estimate_edge_time (struct cgraph_edge *edge)
317 if ((int)edge_growth_cache.length () <= edge->uid
318 || !(ret = edge_growth_cache[edge->uid].time))
319 return do_estimate_edge_time (edge);
320 return ret - (ret > 0);
324 /* Return estimated callee runtime increase after inlning
327 static inline inline_hints
328 estimate_edge_hints (struct cgraph_edge *edge)
331 if ((int)edge_growth_cache.length () <= edge->uid
332 || !(ret = edge_growth_cache[edge->uid].hints))
333 return do_estimate_edge_hints (edge);
337 /* Reset cached value for EDGE. */
340 reset_edge_growth_cache (struct cgraph_edge *edge)
342 if ((int)edge_growth_cache.length () > edge->uid)
344 struct edge_growth_cache_entry zero = {0, 0, 0};
345 edge_growth_cache[edge->uid] = zero;
349 #endif /* GCC_IPA_INLINE_H */