2013-08-02 Paolo Carlini <paolo.carlini@oracle.com>
[official-gcc.git] / gcc / ipa-inline.h
blobb34cb526baded23504924438bc9cdae7d9a94a37
1 /* Inlining decision heuristics.
2 Copyright (C) 2003-2013 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
10 version.
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.
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 #include "ipa-prop.h"
23 /* Representation of inline parameters that do depend on context function is
24 inlined into (i.e. known constant values of function parameters.
26 Conditions that are interesting for function body are collected into CONDS
27 vector. They are of simple for function_param OP VAL, where VAL is
28 IPA invariant. The conditions are then referred by predicates. */
30 typedef struct GTY(()) condition
32 /* If agg_contents is set, this is the offset from which the used data was
33 loaded. */
34 HOST_WIDE_INT offset;
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 } condition;
46 /* Inline hints are reasons why inline heuristics should preffer inlining given
47 function. They are represtented as bitmap of the following values. */
48 enum inline_hints_vals {
49 /* When inlining turns indirect call into a direct call,
50 it is good idea to do so. */
51 INLINE_HINT_indirect_call = 1,
52 /* Inlining may make loop iterations or loop stride known. It is good idea
53 to do so because it enables loop optimizatoins. */
54 INLINE_HINT_loop_iterations = 2,
55 INLINE_HINT_loop_stride = 4,
56 /* Inlining within same strongly connected component of callgraph is often
57 a loss due to increased stack frame usage and prologue setup costs. */
58 INLINE_HINT_same_scc = 8,
59 /* Inlining functions in strongly connected component is not such a great
60 win. */
61 INLINE_HINT_in_scc = 16,
62 /* If function is declared inline by user, it may be good idea to inline
63 it. */
64 INLINE_HINT_declared_inline = 32,
65 /* Programs are usually still organized for non-LTO compilation and thus
66 if functions are in different modules, inlining may not be so important.
68 INLINE_HINT_cross_module = 64,
69 /* If array indexes of loads/stores become known there may be room for
70 further optimization. */
71 INLINE_HINT_array_index = 128
73 typedef int inline_hints;
76 typedef vec<condition, va_gc> *conditions;
78 /* Representation of predicates i.e. formulas using conditions defined
79 above. Predicates are simple logical formulas in conjunctive-disjunctive
80 form.
82 Predicate is array of clauses terminated by 0. Every clause must be true
83 in order to make predicate true.
84 Clauses are represented as bitmaps of conditions. One of conditions
85 must be true in order for clause to be true. */
87 #define MAX_CLAUSES 8
88 typedef unsigned int clause_t;
89 struct GTY(()) predicate
91 clause_t clause[MAX_CLAUSES + 1];
94 /* Represnetation of function body size and time depending on the inline
95 context. We keep simple array of record, every containing of predicate
96 and time/size to account.
98 We keep values scaled up, so fractional sizes and times can be
99 accounted. */
100 #define INLINE_SIZE_SCALE 2
101 #define INLINE_TIME_SCALE (CGRAPH_FREQ_BASE * 2)
102 typedef struct GTY(()) size_time_entry
104 struct predicate predicate;
105 int size;
106 int time;
107 } size_time_entry;
109 /* Function inlining information. */
110 struct GTY(()) inline_summary
112 /* Information about the function body itself. */
114 /* Estimated stack frame consumption by the function. */
115 HOST_WIDE_INT estimated_self_stack_size;
116 /* Size of the function body. */
117 int self_size;
118 /* Time of the function body. */
119 int self_time;
121 /* False when there something makes inlining impossible (such as va_arg). */
122 unsigned inlinable : 1;
124 /* Information about function that will result after applying all the
125 inline decisions present in the callgraph. Generally kept up to
126 date only for functions that are not inline clones. */
128 /* Estimated stack frame consumption by the function. */
129 HOST_WIDE_INT estimated_stack_size;
130 /* Expected offset of the stack frame of inlined function. */
131 HOST_WIDE_INT stack_frame_offset;
132 /* Estimated size of the function after inlining. */
133 int time;
134 int size;
136 /* Conditional size/time information. The summaries are being
137 merged during inlining. */
138 conditions conds;
139 vec<size_time_entry, va_gc> *entry;
141 /* Predicate on when some loop in the function becomes to have known
142 bounds. */
143 struct predicate * GTY((skip)) loop_iterations;
144 /* Predicate on when some loop in the function becomes to have known
145 stride. */
146 struct predicate * GTY((skip)) loop_stride;
147 /* Predicate on when some array indexes become constants. */
148 struct predicate * GTY((skip)) array_index;
149 /* Estimated growth for inlining all copies of the function before start
150 of small functions inlining.
151 This value will get out of date as the callers are duplicated, but
152 using up-to-date value in the badness metric mean a lot of extra
153 expenses. */
154 int growth;
155 /* Number of SCC on the beginning of inlining process. */
156 int scc_no;
160 typedef struct inline_summary inline_summary_t;
161 extern GTY(()) vec<inline_summary_t, va_gc> *inline_summary_vec;
163 /* Information kept about parameter of call site. */
164 struct inline_param_summary
166 /* REG_BR_PROB_BASE based probability that parameter will change in between
167 two invocation of the calls.
168 I.e. loop invariant parameters
169 REG_BR_PROB_BASE/estimated_iterations and regular
170 parameters REG_BR_PROB_BASE.
172 Value 0 is reserved for compile time invariants. */
173 int change_prob;
175 typedef struct inline_param_summary inline_param_summary_t;
177 /* Information kept about callgraph edges. */
178 struct inline_edge_summary
180 /* Estimated size and time of the call statement. */
181 int call_stmt_size;
182 int call_stmt_time;
183 /* Depth of loop nest, 0 means no nesting. */
184 unsigned short int loop_depth;
185 struct predicate *predicate;
186 /* Array indexed by parameters.
187 0 means that parameter change all the time, REG_BR_PROB_BASE means
188 that parameter is constant. */
189 vec<inline_param_summary_t> param;
192 typedef struct inline_edge_summary inline_edge_summary_t;
193 extern vec<inline_edge_summary_t> inline_edge_summary_vec;
195 typedef struct edge_growth_cache_entry
197 int time, size;
198 inline_hints hints;
199 } edge_growth_cache_entry;
201 extern vec<int> node_growth_cache;
202 extern vec<edge_growth_cache_entry> edge_growth_cache;
204 /* In ipa-inline-analysis.c */
205 void debug_inline_summary (struct cgraph_node *);
206 void dump_inline_summaries (FILE *f);
207 void dump_inline_summary (FILE *f, struct cgraph_node *node);
208 void dump_inline_hints (FILE *f, inline_hints);
209 void inline_generate_summary (void);
210 void inline_read_summary (void);
211 void inline_write_summary (void);
212 void inline_free_summary (void);
213 void initialize_inline_failed (struct cgraph_edge *);
214 int estimate_time_after_inlining (struct cgraph_node *, struct cgraph_edge *);
215 int estimate_size_after_inlining (struct cgraph_node *, struct cgraph_edge *);
216 void estimate_ipcp_clone_size_and_time (struct cgraph_node *,
217 vec<tree>, vec<tree>,
218 vec<ipa_agg_jump_function_p>,
219 int *, int *, inline_hints *);
220 int do_estimate_growth (struct cgraph_node *);
221 void inline_merge_summary (struct cgraph_edge *edge);
222 void inline_update_overall_summary (struct cgraph_node *node);
223 int do_estimate_edge_size (struct cgraph_edge *edge);
224 int do_estimate_edge_time (struct cgraph_edge *edge);
225 inline_hints do_estimate_edge_hints (struct cgraph_edge *edge);
226 void initialize_growth_caches (void);
227 void free_growth_caches (void);
228 void compute_inline_parameters (struct cgraph_node *, bool);
230 /* In ipa-inline-transform.c */
231 bool inline_call (struct cgraph_edge *, bool, vec<cgraph_edge_p> *, int *, bool);
232 unsigned int inline_transform (struct cgraph_node *);
233 void clone_inlined_nodes (struct cgraph_edge *e, bool, bool, int *);
235 extern int ncalls_inlined;
236 extern int nfunctions_inlined;
238 static inline struct inline_summary *
239 inline_summary (struct cgraph_node *node)
241 return &(*inline_summary_vec)[node->uid];
244 static inline struct inline_edge_summary *
245 inline_edge_summary (struct cgraph_edge *edge)
247 return &inline_edge_summary_vec[edge->uid];
250 /* Return estimated unit growth after inlning all calls to NODE.
251 Quick accesors to the inline growth caches.
252 For convenience we keep zero 0 as unknown. Because growth
253 can be both positive and negative, we simply increase positive
254 growths by 1. */
255 static inline int
256 estimate_growth (struct cgraph_node *node)
258 int ret;
259 if ((int)node_growth_cache.length () <= node->uid
260 || !(ret = node_growth_cache[node->uid]))
261 return do_estimate_growth (node);
262 return ret - (ret > 0);
266 /* Return estimated size of the inline sequence of EDGE. */
268 static inline int
269 estimate_edge_size (struct cgraph_edge *edge)
271 int ret;
272 if ((int)edge_growth_cache.length () <= edge->uid
273 || !(ret = edge_growth_cache[edge->uid].size))
274 return do_estimate_edge_size (edge);
275 return ret - (ret > 0);
278 /* Return estimated callee growth after inlining EDGE. */
280 static inline int
281 estimate_edge_growth (struct cgraph_edge *edge)
283 #ifdef ENABLE_CHECKING
284 gcc_checking_assert (inline_edge_summary (edge)->call_stmt_size);
285 #endif
286 return (estimate_edge_size (edge)
287 - inline_edge_summary (edge)->call_stmt_size);
290 /* Return estimated callee runtime increase after inlning
291 EDGE. */
293 static inline int
294 estimate_edge_time (struct cgraph_edge *edge)
296 int ret;
297 if ((int)edge_growth_cache.length () <= edge->uid
298 || !(ret = edge_growth_cache[edge->uid].time))
299 return do_estimate_edge_time (edge);
300 return ret - (ret > 0);
304 /* Return estimated callee runtime increase after inlning
305 EDGE. */
307 static inline inline_hints
308 estimate_edge_hints (struct cgraph_edge *edge)
310 inline_hints ret;
311 if ((int)edge_growth_cache.length () <= edge->uid
312 || !(ret = edge_growth_cache[edge->uid].hints))
313 return do_estimate_edge_hints (edge);
314 return ret - 1;
318 /* Reset cached value for NODE. */
320 static inline void
321 reset_node_growth_cache (struct cgraph_node *node)
323 if ((int)node_growth_cache.length () > node->uid)
324 node_growth_cache[node->uid] = 0;
327 /* Reset cached value for EDGE. */
329 static inline void
330 reset_edge_growth_cache (struct cgraph_edge *edge)
332 if ((int)edge_growth_cache.length () > edge->uid)
334 struct edge_growth_cache_entry zero = {0, 0, 0};
335 edge_growth_cache[edge->uid] = zero;