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Do not ICE in IPA inliner.
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1 /* Inlining decision heuristics.
2 Copyright (C) 2003-2019 Free Software Foundation, Inc.
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 /* Inlining decision heuristics
22
23 The implementation of inliner is organized as follows:
24
25 inlining heuristics limits
26
27 can_inline_edge_p allow to check that particular inlining is allowed
28 by the limits specified by user (allowed function growth, growth and so
29 on).
30
31 Functions are inlined when it is obvious the result is profitable (such
32 as functions called once or when inlining reduce code size).
33 In addition to that we perform inlining of small functions and recursive
34 inlining.
35
36 inlining heuristics
37
38 The inliner itself is split into two passes:
39
40 pass_early_inlining
41
42 Simple local inlining pass inlining callees into current function.
43 This pass makes no use of whole unit analysis and thus it can do only
44 very simple decisions based on local properties.
45
46 The strength of the pass is that it is run in topological order
47 (reverse postorder) on the callgraph. Functions are converted into SSA
48 form just before this pass and optimized subsequently. As a result, the
49 callees of the function seen by the early inliner was already optimized
50 and results of early inlining adds a lot of optimization opportunities
51 for the local optimization.
52
53 The pass handle the obvious inlining decisions within the compilation
54 unit - inlining auto inline functions, inlining for size and
55 flattening.
56
57 main strength of the pass is the ability to eliminate abstraction
58 penalty in C++ code (via combination of inlining and early
59 optimization) and thus improve quality of analysis done by real IPA
60 optimizers.
61
62 Because of lack of whole unit knowledge, the pass cannot really make
63 good code size/performance tradeoffs. It however does very simple
64 speculative inlining allowing code size to grow by
65 EARLY_INLINING_INSNS when callee is leaf function. In this case the
66 optimizations performed later are very likely to eliminate the cost.
67
68 pass_ipa_inline
69
70 This is the real inliner able to handle inlining with whole program
71 knowledge. It performs following steps:
72
73 1) inlining of small functions. This is implemented by greedy
74 algorithm ordering all inlinable cgraph edges by their badness and
75 inlining them in this order as long as inline limits allows doing so.
76
77 This heuristics is not very good on inlining recursive calls. Recursive
78 calls can be inlined with results similar to loop unrolling. To do so,
79 special purpose recursive inliner is executed on function when
80 recursive edge is met as viable candidate.
81
82 2) Unreachable functions are removed from callgraph. Inlining leads
83 to devirtualization and other modification of callgraph so functions
84 may become unreachable during the process. Also functions declared as
85 extern inline or virtual functions are removed, since after inlining
86 we no longer need the offline bodies.
87
88 3) Functions called once and not exported from the unit are inlined.
89 This should almost always lead to reduction of code size by eliminating
90 the need for offline copy of the function. */
91
92 #include "config.h"
93 #include "system.h"
94 #include "coretypes.h"
95 #include "backend.h"
96 #include "target.h"
97 #include "rtl.h"
98 #include "tree.h"
99 #include "gimple.h"
100 #include "alloc-pool.h"
101 #include "tree-pass.h"
102 #include "gimple-ssa.h"
103 #include "cgraph.h"
104 #include "lto-streamer.h"
105 #include "trans-mem.h"
106 #include "calls.h"
107 #include "tree-inline.h"
108 #include "params.h"
109 #include "profile.h"
110 #include "symbol-summary.h"
111 #include "tree-vrp.h"
112 #include "ipa-prop.h"
113 #include "ipa-fnsummary.h"
114 #include "ipa-inline.h"
115 #include "ipa-utils.h"
116 #include "sreal.h"
117 #include "auto-profile.h"
118 #include "builtins.h"
119 #include "fibonacci_heap.h"
120 #include "stringpool.h"
121 #include "attribs.h"
122 #include "asan.h"
123
124 typedef fibonacci_heap <sreal, cgraph_edge> edge_heap_t;
125 typedef fibonacci_node <sreal, cgraph_edge> edge_heap_node_t;
126
127 /* Statistics we collect about inlining algorithm. */
128 static int overall_size;
129 static profile_count max_count;
130 static profile_count spec_rem;
131
132 /* Return false when inlining edge E would lead to violating
133 limits on function unit growth or stack usage growth.
134
135 The relative function body growth limit is present generally
136 to avoid problems with non-linear behavior of the compiler.
137 To allow inlining huge functions into tiny wrapper, the limit
138 is always based on the bigger of the two functions considered.
139
140 For stack growth limits we always base the growth in stack usage
141 of the callers. We want to prevent applications from segfaulting
142 on stack overflow when functions with huge stack frames gets
143 inlined. */
144
145 static bool
146 caller_growth_limits (struct cgraph_edge *e)
147 {
148 struct cgraph_node *to = e->caller;
149 struct cgraph_node *what = e->callee->ultimate_alias_target ();
150 int newsize;
151 int limit = 0;
152 HOST_WIDE_INT stack_size_limit = 0, inlined_stack;
153 ipa_fn_summary *info, *what_info;
154 ipa_fn_summary *outer_info = ipa_fn_summaries->get (to);
155
156 /* Look for function e->caller is inlined to. While doing
157 so work out the largest function body on the way. As
158 described above, we want to base our function growth
159 limits based on that. Not on the self size of the
160 outer function, not on the self size of inline code
161 we immediately inline to. This is the most relaxed
162 interpretation of the rule "do not grow large functions
163 too much in order to prevent compiler from exploding". */
164 while (true)
165 {
166 info = ipa_fn_summaries->get (to);
167 if (limit < info->self_size)
168 limit = info->self_size;
169 if (stack_size_limit < info->estimated_self_stack_size)
170 stack_size_limit = info->estimated_self_stack_size;
171 if (to->global.inlined_to)
172 to = to->callers->caller;
173 else
174 break;
175 }
176
177 what_info = ipa_fn_summaries->get (what);
178
179 if (limit < what_info->self_size)
180 limit = what_info->self_size;
181
182 limit += limit * PARAM_VALUE (PARAM_LARGE_FUNCTION_GROWTH) / 100;
183
184 /* Check the size after inlining against the function limits. But allow
185 the function to shrink if it went over the limits by forced inlining. */
186 newsize = estimate_size_after_inlining (to, e);
187 if (newsize >= info->size
188 && newsize > PARAM_VALUE (PARAM_LARGE_FUNCTION_INSNS)
189 && newsize > limit)
190 {
191 e->inline_failed = CIF_LARGE_FUNCTION_GROWTH_LIMIT;
192 return false;
193 }
194
195 if (!what_info->estimated_stack_size)
196 return true;
197
198 /* FIXME: Stack size limit often prevents inlining in Fortran programs
199 due to large i/o datastructures used by the Fortran front-end.
200 We ought to ignore this limit when we know that the edge is executed
201 on every invocation of the caller (i.e. its call statement dominates
202 exit block). We do not track this information, yet. */
203 stack_size_limit += ((gcov_type)stack_size_limit
204 * PARAM_VALUE (PARAM_STACK_FRAME_GROWTH) / 100);
205
206 inlined_stack = (outer_info->stack_frame_offset
207 + outer_info->estimated_self_stack_size
208 + what_info->estimated_stack_size);
209 /* Check new stack consumption with stack consumption at the place
210 stack is used. */
211 if (inlined_stack > stack_size_limit
212 /* If function already has large stack usage from sibling
213 inline call, we can inline, too.
214 This bit overoptimistically assume that we are good at stack
215 packing. */
216 && inlined_stack > info->estimated_stack_size
217 && inlined_stack > PARAM_VALUE (PARAM_LARGE_STACK_FRAME))
218 {
219 e->inline_failed = CIF_LARGE_STACK_FRAME_GROWTH_LIMIT;
220 return false;
221 }
222 return true;
223 }
224
225 /* Dump info about why inlining has failed. */
226
227 static void
228 report_inline_failed_reason (struct cgraph_edge *e)
229 {
230 if (dump_enabled_p ())
231 {
232 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
233 " not inlinable: %C -> %C, %s\n",
234 e->caller, e->callee,
235 cgraph_inline_failed_string (e->inline_failed));
236 if ((e->inline_failed == CIF_TARGET_OPTION_MISMATCH
237 || e->inline_failed == CIF_OPTIMIZATION_MISMATCH)
238 && e->caller->lto_file_data
239 && e->callee->ultimate_alias_target ()->lto_file_data)
240 {
241 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
242 " LTO objects: %s, %s\n",
243 e->caller->lto_file_data->file_name,
244 e->callee->ultimate_alias_target ()->lto_file_data->file_name);
245 }
246 if (e->inline_failed == CIF_TARGET_OPTION_MISMATCH)
247 if (dump_file)
248 cl_target_option_print_diff
249 (dump_file, 2, target_opts_for_fn (e->caller->decl),
250 target_opts_for_fn (e->callee->ultimate_alias_target ()->decl));
251 if (e->inline_failed == CIF_OPTIMIZATION_MISMATCH)
252 if (dump_file)
253 cl_optimization_print_diff
254 (dump_file, 2, opts_for_fn (e->caller->decl),
255 opts_for_fn (e->callee->ultimate_alias_target ()->decl));
256 }
257 }
258
259 /* Decide whether sanitizer-related attributes allow inlining. */
260
261 static bool
262 sanitize_attrs_match_for_inline_p (const_tree caller, const_tree callee)
263 {
264 if (!caller || !callee)
265 return true;
266
267 /* Allow inlining always_inline functions into no_sanitize_address
268 functions. */
269 if (!sanitize_flags_p (SANITIZE_ADDRESS, caller)
270 && lookup_attribute ("always_inline", DECL_ATTRIBUTES (callee)))
271 return true;
272
273 return ((sanitize_flags_p (SANITIZE_ADDRESS, caller)
274 == sanitize_flags_p (SANITIZE_ADDRESS, callee))
275 && (sanitize_flags_p (SANITIZE_POINTER_COMPARE, caller)
276 == sanitize_flags_p (SANITIZE_POINTER_COMPARE, callee))
277 && (sanitize_flags_p (SANITIZE_POINTER_SUBTRACT, caller)
278 == sanitize_flags_p (SANITIZE_POINTER_SUBTRACT, callee)));
279 }
280
281 /* Used for flags where it is safe to inline when caller's value is
282 grater than callee's. */
283 #define check_maybe_up(flag) \
284 (opts_for_fn (caller->decl)->x_##flag \
285 != opts_for_fn (callee->decl)->x_##flag \
286 && (!always_inline \
287 || opts_for_fn (caller->decl)->x_##flag \
288 < opts_for_fn (callee->decl)->x_##flag))
289 /* Used for flags where it is safe to inline when caller's value is
290 smaller than callee's. */
291 #define check_maybe_down(flag) \
292 (opts_for_fn (caller->decl)->x_##flag \
293 != opts_for_fn (callee->decl)->x_##flag \
294 && (!always_inline \
295 || opts_for_fn (caller->decl)->x_##flag \
296 > opts_for_fn (callee->decl)->x_##flag))
297 /* Used for flags where exact match is needed for correctness. */
298 #define check_match(flag) \
299 (opts_for_fn (caller->decl)->x_##flag \
300 != opts_for_fn (callee->decl)->x_##flag)
301
302 /* Decide if we can inline the edge and possibly update
303 inline_failed reason.
304 We check whether inlining is possible at all and whether
305 caller growth limits allow doing so.
306
307 if REPORT is true, output reason to the dump file. */
308
309 static bool
310 can_inline_edge_p (struct cgraph_edge *e, bool report,
311 bool early = false)
312 {
313 gcc_checking_assert (e->inline_failed);
314
315 if (cgraph_inline_failed_type (e->inline_failed) == CIF_FINAL_ERROR)
316 {
317 if (report)
318 report_inline_failed_reason (e);
319 return false;
320 }
321
322 bool inlinable = true;
323 enum availability avail;
324 cgraph_node *caller = e->caller->global.inlined_to
325 ? e->caller->global.inlined_to : e->caller;
326 cgraph_node *callee = e->callee->ultimate_alias_target (&avail, caller);
327
328 if (!callee->definition)
329 {
330 e->inline_failed = CIF_BODY_NOT_AVAILABLE;
331 inlinable = false;
332 }
333 if (!early && (!opt_for_fn (callee->decl, optimize)
334 || !opt_for_fn (caller->decl, optimize)))
335 {
336 e->inline_failed = CIF_FUNCTION_NOT_OPTIMIZED;
337 inlinable = false;
338 }
339 else if (callee->calls_comdat_local)
340 {
341 e->inline_failed = CIF_USES_COMDAT_LOCAL;
342 inlinable = false;
343 }
344 else if (avail <= AVAIL_INTERPOSABLE)
345 {
346 e->inline_failed = CIF_OVERWRITABLE;
347 inlinable = false;
348 }
349 /* All edges with call_stmt_cannot_inline_p should have inline_failed
350 initialized to one of FINAL_ERROR reasons. */
351 else if (e->call_stmt_cannot_inline_p)
352 gcc_unreachable ();
353 /* Don't inline if the functions have different EH personalities. */
354 else if (DECL_FUNCTION_PERSONALITY (caller->decl)
355 && DECL_FUNCTION_PERSONALITY (callee->decl)
356 && (DECL_FUNCTION_PERSONALITY (caller->decl)
357 != DECL_FUNCTION_PERSONALITY (callee->decl)))
358 {
359 e->inline_failed = CIF_EH_PERSONALITY;
360 inlinable = false;
361 }
362 /* TM pure functions should not be inlined into non-TM_pure
363 functions. */
364 else if (is_tm_pure (callee->decl) && !is_tm_pure (caller->decl))
365 {
366 e->inline_failed = CIF_UNSPECIFIED;
367 inlinable = false;
368 }
369 /* Check compatibility of target optimization options. */
370 else if (!targetm.target_option.can_inline_p (caller->decl,
371 callee->decl))
372 {
373 e->inline_failed = CIF_TARGET_OPTION_MISMATCH;
374 inlinable = false;
375 }
376 else if (ipa_fn_summaries->get (callee) == NULL
377 || !ipa_fn_summaries->get (callee)->inlinable)
378 {
379 e->inline_failed = CIF_FUNCTION_NOT_INLINABLE;
380 inlinable = false;
381 }
382 /* Don't inline a function with mismatched sanitization attributes. */
383 else if (!sanitize_attrs_match_for_inline_p (caller->decl, callee->decl))
384 {
385 e->inline_failed = CIF_ATTRIBUTE_MISMATCH;
386 inlinable = false;
387 }
388 if (!inlinable && report)
389 report_inline_failed_reason (e);
390 return inlinable;
391 }
392
393 /* Return inlining_insns_single limit for function N. If HINT is true
394 scale up the bound. */
395
396 static int
397 inline_insns_single (cgraph_node *n, bool hint)
398 {
399 if (opt_for_fn (n->decl, optimize) >= 3)
400 {
401 if (hint)
402 return PARAM_VALUE (PARAM_MAX_INLINE_INSNS_SINGLE)
403 * PARAM_VALUE (PARAM_INLINE_HEURISTICS_HINT_PERCENT) / 100;
404 return PARAM_VALUE (PARAM_MAX_INLINE_INSNS_SINGLE);
405 }
406 else
407 {
408 if (hint)
409 return PARAM_VALUE (PARAM_MAX_INLINE_INSNS_SINGLE_O2)
410 * PARAM_VALUE (PARAM_INLINE_HEURISTICS_HINT_PERCENT_O2) / 100;
411 return PARAM_VALUE (PARAM_MAX_INLINE_INSNS_SINGLE_O2);
412 }
413 }
414
415 /* Return inlining_insns_auto limit for function N. If HINT is true
416 scale up the bound. */
417
418 static int
419 inline_insns_auto (cgraph_node *n, bool hint)
420 {
421 if (opt_for_fn (n->decl, optimize) >= 3)
422 {
423 if (hint)
424 return PARAM_VALUE (PARAM_MAX_INLINE_INSNS_AUTO)
425 * PARAM_VALUE (PARAM_INLINE_HEURISTICS_HINT_PERCENT) / 100;
426 return PARAM_VALUE (PARAM_MAX_INLINE_INSNS_AUTO);
427 }
428 else
429 {
430 if (hint)
431 return PARAM_VALUE (PARAM_MAX_INLINE_INSNS_AUTO_O2)
432 * PARAM_VALUE (PARAM_INLINE_HEURISTICS_HINT_PERCENT_O2) / 100;
433 return PARAM_VALUE (PARAM_MAX_INLINE_INSNS_AUTO_O2);
434 }
435 }
436
437 /* Decide if we can inline the edge and possibly update
438 inline_failed reason.
439 We check whether inlining is possible at all and whether
440 caller growth limits allow doing so.
441
442 if REPORT is true, output reason to the dump file.
443
444 if DISREGARD_LIMITS is true, ignore size limits. */
445
446 static bool
447 can_inline_edge_by_limits_p (struct cgraph_edge *e, bool report,
448 bool disregard_limits = false, bool early = false)
449 {
450 gcc_checking_assert (e->inline_failed);
451
452 if (cgraph_inline_failed_type (e->inline_failed) == CIF_FINAL_ERROR)
453 {
454 if (report)
455 report_inline_failed_reason (e);
456 return false;
457 }
458
459 bool inlinable = true;
460 enum availability avail;
461 cgraph_node *caller = e->caller->global.inlined_to
462 ? e->caller->global.inlined_to : e->caller;
463 cgraph_node *callee = e->callee->ultimate_alias_target (&avail, caller);
464 tree caller_tree = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (caller->decl);
465 tree callee_tree
466 = callee ? DECL_FUNCTION_SPECIFIC_OPTIMIZATION (callee->decl) : NULL;
467 /* Check if caller growth allows the inlining. */
468 if (!DECL_DISREGARD_INLINE_LIMITS (callee->decl)
469 && !disregard_limits
470 && !lookup_attribute ("flatten",
471 DECL_ATTRIBUTES (caller->decl))
472 && !caller_growth_limits (e))
473 inlinable = false;
474 else if (callee->externally_visible
475 && !DECL_DISREGARD_INLINE_LIMITS (callee->decl)
476 && flag_live_patching == LIVE_PATCHING_INLINE_ONLY_STATIC)
477 {
478 e->inline_failed = CIF_EXTERN_LIVE_ONLY_STATIC;
479 inlinable = false;
480 }
481 /* Don't inline a function with a higher optimization level than the
482 caller. FIXME: this is really just tip of iceberg of handling
483 optimization attribute. */
484 else if (caller_tree != callee_tree)
485 {
486 bool always_inline =
487 (DECL_DISREGARD_INLINE_LIMITS (callee->decl)
488 && lookup_attribute ("always_inline",
489 DECL_ATTRIBUTES (callee->decl)));
490 ipa_fn_summary *caller_info = ipa_fn_summaries->get (caller);
491 ipa_fn_summary *callee_info = ipa_fn_summaries->get (callee);
492
493 /* Until GCC 4.9 we did not check the semantics-altering flags
494 below and inlined across optimization boundaries.
495 Enabling checks below breaks several packages by refusing
496 to inline library always_inline functions. See PR65873.
497 Disable the check for early inlining for now until better solution
498 is found. */
499 if (always_inline && early)
500 ;
501 /* There are some options that change IL semantics which means
502 we cannot inline in these cases for correctness reason.
503 Not even for always_inline declared functions. */
504 else if (check_match (flag_wrapv)
505 || check_match (flag_trapv)
506 || check_match (flag_pcc_struct_return)
507 /* When caller or callee does FP math, be sure FP codegen flags
508 compatible. */
509 || ((caller_info->fp_expressions && callee_info->fp_expressions)
510 && (check_maybe_up (flag_rounding_math)
511 || check_maybe_up (flag_trapping_math)
512 || check_maybe_down (flag_unsafe_math_optimizations)
513 || check_maybe_down (flag_finite_math_only)
514 || check_maybe_up (flag_signaling_nans)
515 || check_maybe_down (flag_cx_limited_range)
516 || check_maybe_up (flag_signed_zeros)
517 || check_maybe_down (flag_associative_math)
518 || check_maybe_down (flag_reciprocal_math)
519 || check_maybe_down (flag_fp_int_builtin_inexact)
520 /* Strictly speaking only when the callee contains function
521 calls that may end up setting errno. */
522 || check_maybe_up (flag_errno_math)))
523 /* We do not want to make code compiled with exceptions to be
524 brought into a non-EH function unless we know that the callee
525 does not throw.
526 This is tracked by DECL_FUNCTION_PERSONALITY. */
527 || (check_maybe_up (flag_non_call_exceptions)
528 && DECL_FUNCTION_PERSONALITY (callee->decl))
529 || (check_maybe_up (flag_exceptions)
530 && DECL_FUNCTION_PERSONALITY (callee->decl))
531 /* When devirtualization is diabled for callee, it is not safe
532 to inline it as we possibly mangled the type info.
533 Allow early inlining of always inlines. */
534 || (!early && check_maybe_down (flag_devirtualize)))
535 {
536 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
537 inlinable = false;
538 }
539 /* gcc.dg/pr43564.c. Apply user-forced inline even at -O0. */
540 else if (always_inline)
541 ;
542 /* When user added an attribute to the callee honor it. */
543 else if (lookup_attribute ("optimize", DECL_ATTRIBUTES (callee->decl))
544 && opts_for_fn (caller->decl) != opts_for_fn (callee->decl))
545 {
546 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
547 inlinable = false;
548 }
549 /* If explicit optimize attribute are not used, the mismatch is caused
550 by different command line options used to build different units.
551 Do not care about COMDAT functions - those are intended to be
552 optimized with the optimization flags of module they are used in.
553 Also do not care about mixing up size/speed optimization when
554 DECL_DISREGARD_INLINE_LIMITS is set. */
555 else if ((callee->merged_comdat
556 && !lookup_attribute ("optimize",
557 DECL_ATTRIBUTES (caller->decl)))
558 || DECL_DISREGARD_INLINE_LIMITS (callee->decl))
559 ;
560 /* If mismatch is caused by merging two LTO units with different
561 optimizationflags we want to be bit nicer. However never inline
562 if one of functions is not optimized at all. */
563 else if (!opt_for_fn (callee->decl, optimize)
564 || !opt_for_fn (caller->decl, optimize))
565 {
566 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
567 inlinable = false;
568 }
569 /* If callee is optimized for size and caller is not, allow inlining if
570 code shrinks or we are in MAX_INLINE_INSNS_SINGLE limit and callee
571 is inline (and thus likely an unified comdat). This will allow caller
572 to run faster. */
573 else if (opt_for_fn (callee->decl, optimize_size)
574 > opt_for_fn (caller->decl, optimize_size))
575 {
576 int growth = estimate_edge_growth (e);
577 if (growth > PARAM_VALUE (PARAM_MAX_INLINE_INSNS_SIZE)
578 && (!DECL_DECLARED_INLINE_P (callee->decl)
579 && growth >= MAX (inline_insns_single (caller, false),
580 inline_insns_auto (caller, false))))
581 {
582 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
583 inlinable = false;
584 }
585 }
586 /* If callee is more aggressively optimized for performance than caller,
587 we generally want to inline only cheap (runtime wise) functions. */
588 else if (opt_for_fn (callee->decl, optimize_size)
589 < opt_for_fn (caller->decl, optimize_size)
590 || (opt_for_fn (callee->decl, optimize)
591 > opt_for_fn (caller->decl, optimize)))
592 {
593 if (estimate_edge_time (e)
594 >= 20 + ipa_call_summaries->get (e)->call_stmt_time)
595 {
596 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
597 inlinable = false;
598 }
599 }
600
601 }
602
603 if (!inlinable && report)
604 report_inline_failed_reason (e);
605 return inlinable;
606 }
607
608
609 /* Return true if the edge E is inlinable during early inlining. */
610
611 static bool
612 can_early_inline_edge_p (struct cgraph_edge *e)
613 {
614 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
615 /* Early inliner might get called at WPA stage when IPA pass adds new
616 function. In this case we cannot really do any of early inlining
617 because function bodies are missing. */
618 if (cgraph_inline_failed_type (e->inline_failed) == CIF_FINAL_ERROR)
619 return false;
620 if (!gimple_has_body_p (callee->decl))
621 {
622 e->inline_failed = CIF_BODY_NOT_AVAILABLE;
623 return false;
624 }
625 /* In early inliner some of callees may not be in SSA form yet
626 (i.e. the callgraph is cyclic and we did not process
627 the callee by early inliner, yet). We don't have CIF code for this
628 case; later we will re-do the decision in the real inliner. */
629 if (!gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->caller->decl))
630 || !gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->decl)))
631 {
632 if (dump_enabled_p ())
633 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
634 " edge not inlinable: not in SSA form\n");
635 return false;
636 }
637 if (!can_inline_edge_p (e, true, true)
638 || !can_inline_edge_by_limits_p (e, true, false, true))
639 return false;
640 return true;
641 }
642
643
644 /* Return number of calls in N. Ignore cheap builtins. */
645
646 static int
647 num_calls (struct cgraph_node *n)
648 {
649 struct cgraph_edge *e;
650 int num = 0;
651
652 for (e = n->callees; e; e = e->next_callee)
653 if (!is_inexpensive_builtin (e->callee->decl))
654 num++;
655 return num;
656 }
657
658
659 /* Return true if we are interested in inlining small function. */
660
661 static bool
662 want_early_inline_function_p (struct cgraph_edge *e)
663 {
664 bool want_inline = true;
665 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
666
667 if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
668 ;
669 /* For AutoFDO, we need to make sure that before profile summary, all
670 hot paths' IR look exactly the same as profiled binary. As a result,
671 in einliner, we will disregard size limit and inline those callsites
672 that are:
673 * inlined in the profiled binary, and
674 * the cloned callee has enough samples to be considered "hot". */
675 else if (flag_auto_profile && afdo_callsite_hot_enough_for_early_inline (e))
676 ;
677 else if (!DECL_DECLARED_INLINE_P (callee->decl)
678 && !opt_for_fn (e->caller->decl, flag_inline_small_functions))
679 {
680 e->inline_failed = CIF_FUNCTION_NOT_INLINE_CANDIDATE;
681 report_inline_failed_reason (e);
682 want_inline = false;
683 }
684 else
685 {
686 int growth = estimate_edge_growth (e);
687 int n;
688 int early_inlining_insns = opt_for_fn (e->caller->decl, optimize) >= 3
689 ? PARAM_VALUE (PARAM_EARLY_INLINING_INSNS)
690 : PARAM_VALUE (PARAM_EARLY_INLINING_INSNS_O2);
691
692
693 if (growth <= PARAM_VALUE (PARAM_MAX_INLINE_INSNS_SIZE))
694 ;
695 else if (!e->maybe_hot_p ())
696 {
697 if (dump_enabled_p ())
698 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
699 " will not early inline: %C->%C, "
700 "call is cold and code would grow by %i\n",
701 e->caller, callee,
702 growth);
703 want_inline = false;
704 }
705 else if (growth > early_inlining_insns)
706 {
707 if (dump_enabled_p ())
708 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
709 " will not early inline: %C->%C, "
710 "growth %i exceeds --param early-inlining-insns%s\n",
711 e->caller, callee, growth,
712 opt_for_fn (e->caller->decl, optimize) >= 3
713 ? "" : "-O2");
714 want_inline = false;
715 }
716 else if ((n = num_calls (callee)) != 0
717 && growth * (n + 1) > early_inlining_insns)
718 {
719 if (dump_enabled_p ())
720 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
721 " will not early inline: %C->%C, "
722 "growth %i exceeds --param early-inlining-insns%s "
723 "divided by number of calls\n",
724 e->caller, callee, growth,
725 opt_for_fn (e->caller->decl, optimize) >= 3
726 ? "" : "-O2");
727 want_inline = false;
728 }
729 }
730 return want_inline;
731 }
732
733 /* Compute time of the edge->caller + edge->callee execution when inlining
734 does not happen. */
735
736 inline sreal
737 compute_uninlined_call_time (struct cgraph_edge *edge,
738 sreal uninlined_call_time)
739 {
740 cgraph_node *caller = (edge->caller->global.inlined_to
741 ? edge->caller->global.inlined_to
742 : edge->caller);
743
744 sreal freq = edge->sreal_frequency ();
745 if (freq > 0)
746 uninlined_call_time *= freq;
747 else
748 uninlined_call_time = uninlined_call_time >> 11;
749
750 sreal caller_time = ipa_fn_summaries->get (caller)->time;
751 return uninlined_call_time + caller_time;
752 }
753
754 /* Same as compute_uinlined_call_time but compute time when inlining
755 does happen. */
756
757 inline sreal
758 compute_inlined_call_time (struct cgraph_edge *edge,
759 sreal time)
760 {
761 cgraph_node *caller = (edge->caller->global.inlined_to
762 ? edge->caller->global.inlined_to
763 : edge->caller);
764 sreal caller_time = ipa_fn_summaries->get (caller)->time;
765
766 sreal freq = edge->sreal_frequency ();
767 if (freq > 0)
768 time *= freq;
769 else
770 time = time >> 11;
771
772 /* This calculation should match one in ipa-inline-analysis.c
773 (estimate_edge_size_and_time). */
774 time -= (sreal)ipa_call_summaries->get (edge)->call_stmt_time * freq;
775 time += caller_time;
776 if (time <= 0)
777 time = ((sreal) 1) >> 8;
778 gcc_checking_assert (time >= 0);
779 return time;
780 }
781
782 /* Return true if the speedup for inlining E is bigger than
783 PARAM_MAX_INLINE_MIN_SPEEDUP. */
784
785 static bool
786 big_speedup_p (struct cgraph_edge *e)
787 {
788 sreal unspec_time;
789 sreal spec_time = estimate_edge_time (e, &unspec_time);
790 sreal time = compute_uninlined_call_time (e, unspec_time);
791 sreal inlined_time = compute_inlined_call_time (e, spec_time);
792 cgraph_node *caller = e->caller->global.inlined_to
793 ? e->caller->global.inlined_to
794 : e->caller;
795 int limit = opt_for_fn (caller->decl, optimize) >= 3
796 ? PARAM_VALUE (PARAM_INLINE_MIN_SPEEDUP)
797 : PARAM_VALUE (PARAM_INLINE_MIN_SPEEDUP_O2);
798
799 if ((time - inlined_time) * 100 > time * limit)
800 return true;
801 return false;
802 }
803
804 /* Return true if we are interested in inlining small function.
805 When REPORT is true, report reason to dump file. */
806
807 static bool
808 want_inline_small_function_p (struct cgraph_edge *e, bool report)
809 {
810 bool want_inline = true;
811 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
812
813 /* Allow this function to be called before can_inline_edge_p,
814 since it's usually cheaper. */
815 if (cgraph_inline_failed_type (e->inline_failed) == CIF_FINAL_ERROR)
816 want_inline = false;
817 else if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
818 ;
819 else if (!DECL_DECLARED_INLINE_P (callee->decl)
820 && !opt_for_fn (e->caller->decl, flag_inline_small_functions))
821 {
822 e->inline_failed = CIF_FUNCTION_NOT_INLINE_CANDIDATE;
823 want_inline = false;
824 }
825 /* Do fast and conservative check if the function can be good
826 inline candidate. */
827 else if ((!DECL_DECLARED_INLINE_P (callee->decl)
828 && (!e->count.ipa ().initialized_p () || !e->maybe_hot_p ()))
829 && ipa_fn_summaries->get (callee)->min_size
830 - ipa_call_summaries->get (e)->call_stmt_size
831 > inline_insns_auto (e->caller, true))
832 {
833 if (opt_for_fn (e->caller->decl, optimize) >= 3)
834 e->inline_failed = CIF_MAX_INLINE_INSNS_AUTO_LIMIT;
835 else
836 e->inline_failed = CIF_MAX_INLINE_INSNS_AUTO_O2_LIMIT;
837 want_inline = false;
838 }
839 else if ((DECL_DECLARED_INLINE_P (callee->decl)
840 || e->count.ipa ().nonzero_p ())
841 && ipa_fn_summaries->get (callee)->min_size
842 - ipa_call_summaries->get (e)->call_stmt_size
843 > inline_insns_single (e->caller, true))
844 {
845 if (opt_for_fn (e->caller->decl, optimize) >= 3)
846 e->inline_failed = (DECL_DECLARED_INLINE_P (callee->decl)
847 ? CIF_MAX_INLINE_INSNS_SINGLE_LIMIT
848 : CIF_MAX_INLINE_INSNS_AUTO_LIMIT);
849 else
850 e->inline_failed = (DECL_DECLARED_INLINE_P (callee->decl)
851 ? CIF_MAX_INLINE_INSNS_SINGLE_O2_LIMIT
852 : CIF_MAX_INLINE_INSNS_AUTO_O2_LIMIT);
853 want_inline = false;
854 }
855 else
856 {
857 int growth = estimate_edge_growth (e);
858 ipa_hints hints = estimate_edge_hints (e);
859 bool apply_hints = (hints & (INLINE_HINT_indirect_call
860 | INLINE_HINT_known_hot
861 | INLINE_HINT_loop_iterations
862 | INLINE_HINT_loop_stride));
863
864 if (growth <= PARAM_VALUE (PARAM_MAX_INLINE_INSNS_SIZE))
865 ;
866 /* Apply MAX_INLINE_INSNS_SINGLE limit. Do not do so when
867 hints suggests that inlining given function is very profitable.
868 Avoid computation of big_speedup_p when not necessary to change
869 outcome of decision. */
870 else if (DECL_DECLARED_INLINE_P (callee->decl)
871 && growth >= inline_insns_single (e->caller, apply_hints)
872 && (apply_hints
873 || growth >= inline_insns_single (e->caller, true)
874 || !big_speedup_p (e)))
875 {
876 if (opt_for_fn (e->caller->decl, optimize) >= 3)
877 e->inline_failed = CIF_MAX_INLINE_INSNS_SINGLE_LIMIT;
878 else
879 e->inline_failed = CIF_MAX_INLINE_INSNS_SINGLE_O2_LIMIT;
880 want_inline = false;
881 }
882 else if (!DECL_DECLARED_INLINE_P (callee->decl)
883 && !opt_for_fn (e->caller->decl, flag_inline_functions)
884 && growth >= PARAM_VALUE (PARAM_MAX_INLINE_INSNS_SMALL))
885 {
886 /* growth_likely_positive is expensive, always test it last. */
887 if (growth >= inline_insns_single (e->caller, false)
888 || growth_likely_positive (callee, growth))
889 {
890 e->inline_failed = CIF_NOT_DECLARED_INLINED;
891 want_inline = false;
892 }
893 }
894 /* Apply MAX_INLINE_INSNS_AUTO limit for functions not declared inline.
895 Bypass the limit when speedup seems big. */
896 else if (!DECL_DECLARED_INLINE_P (callee->decl)
897 && growth >= inline_insns_auto (e->caller, apply_hints)
898 && (apply_hints
899 || growth >= inline_insns_auto (e->caller, true)
900 || !big_speedup_p (e)))
901 {
902 /* growth_likely_positive is expensive, always test it last. */
903 if (growth >= inline_insns_single (e->caller, false)
904 || growth_likely_positive (callee, growth))
905 {
906 if (opt_for_fn (e->caller->decl, optimize) >= 3)
907 e->inline_failed = CIF_MAX_INLINE_INSNS_AUTO_LIMIT;
908 else
909 e->inline_failed = CIF_MAX_INLINE_INSNS_AUTO_O2_LIMIT;
910 want_inline = false;
911 }
912 }
913 /* If call is cold, do not inline when function body would grow. */
914 else if (!e->maybe_hot_p ()
915 && (growth >= inline_insns_single (e->caller, false)
916 || growth_likely_positive (callee, growth)))
917 {
918 e->inline_failed = CIF_UNLIKELY_CALL;
919 want_inline = false;
920 }
921 }
922 if (!want_inline && report)
923 report_inline_failed_reason (e);
924 return want_inline;
925 }
926
927 /* EDGE is self recursive edge.
928 We hand two cases - when function A is inlining into itself
929 or when function A is being inlined into another inliner copy of function
930 A within function B.
931
932 In first case OUTER_NODE points to the toplevel copy of A, while
933 in the second case OUTER_NODE points to the outermost copy of A in B.
934
935 In both cases we want to be extra selective since
936 inlining the call will just introduce new recursive calls to appear. */
937
938 static bool
939 want_inline_self_recursive_call_p (struct cgraph_edge *edge,
940 struct cgraph_node *outer_node,
941 bool peeling,
942 int depth)
943 {
944 char const *reason = NULL;
945 bool want_inline = true;
946 sreal caller_freq = 1;
947 int max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO);
948
949 if (DECL_DECLARED_INLINE_P (edge->caller->decl))
950 max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH);
951
952 if (!edge->maybe_hot_p ())
953 {
954 reason = "recursive call is cold";
955 want_inline = false;
956 }
957 else if (depth > max_depth)
958 {
959 reason = "--param max-inline-recursive-depth exceeded.";
960 want_inline = false;
961 }
962 else if (outer_node->global.inlined_to
963 && (caller_freq = outer_node->callers->sreal_frequency ()) == 0)
964 {
965 reason = "caller frequency is 0";
966 want_inline = false;
967 }
968
969 if (!want_inline)
970 ;
971 /* Inlining of self recursive function into copy of itself within other
972 function is transformation similar to loop peeling.
973
974 Peeling is profitable if we can inline enough copies to make probability
975 of actual call to the self recursive function very small. Be sure that
976 the probability of recursion is small.
977
978 We ensure that the frequency of recursing is at most 1 - (1/max_depth).
979 This way the expected number of recursion is at most max_depth. */
980 else if (peeling)
981 {
982 sreal max_prob = (sreal)1 - ((sreal)1 / (sreal)max_depth);
983 int i;
984 for (i = 1; i < depth; i++)
985 max_prob = max_prob * max_prob;
986 if (edge->sreal_frequency () >= max_prob * caller_freq)
987 {
988 reason = "frequency of recursive call is too large";
989 want_inline = false;
990 }
991 }
992 /* Recursive inlining, i.e. equivalent of unrolling, is profitable if
993 recursion depth is large. We reduce function call overhead and increase
994 chances that things fit in hardware return predictor.
995
996 Recursive inlining might however increase cost of stack frame setup
997 actually slowing down functions whose recursion tree is wide rather than
998 deep.
999
1000 Deciding reliably on when to do recursive inlining without profile feedback
1001 is tricky. For now we disable recursive inlining when probability of self
1002 recursion is low.
1003
1004 Recursive inlining of self recursive call within loop also results in
1005 large loop depths that generally optimize badly. We may want to throttle
1006 down inlining in those cases. In particular this seems to happen in one
1007 of libstdc++ rb tree methods. */
1008 else
1009 {
1010 if (edge->sreal_frequency () * 100
1011 <= caller_freq
1012 * PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY))
1013 {
1014 reason = "frequency of recursive call is too small";
1015 want_inline = false;
1016 }
1017 }
1018 if (!want_inline && dump_enabled_p ())
1019 dump_printf_loc (MSG_MISSED_OPTIMIZATION, edge->call_stmt,
1020 " not inlining recursively: %s\n", reason);
1021 return want_inline;
1022 }
1023
1024 /* Return true when NODE has uninlinable caller;
1025 set HAS_HOT_CALL if it has hot call.
1026 Worker for cgraph_for_node_and_aliases. */
1027
1028 static bool
1029 check_callers (struct cgraph_node *node, void *has_hot_call)
1030 {
1031 struct cgraph_edge *e;
1032 for (e = node->callers; e; e = e->next_caller)
1033 {
1034 if (!opt_for_fn (e->caller->decl, flag_inline_functions_called_once)
1035 || !opt_for_fn (e->caller->decl, optimize))
1036 return true;
1037 if (!can_inline_edge_p (e, true))
1038 return true;
1039 if (e->recursive_p ())
1040 return true;
1041 if (!can_inline_edge_by_limits_p (e, true))
1042 return true;
1043 if (!(*(bool *)has_hot_call) && e->maybe_hot_p ())
1044 *(bool *)has_hot_call = true;
1045 }
1046 return false;
1047 }
1048
1049 /* If NODE has a caller, return true. */
1050
1051 static bool
1052 has_caller_p (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
1053 {
1054 if (node->callers)
1055 return true;
1056 return false;
1057 }
1058
1059 /* Decide if inlining NODE would reduce unit size by eliminating
1060 the offline copy of function.
1061 When COLD is true the cold calls are considered, too. */
1062
1063 static bool
1064 want_inline_function_to_all_callers_p (struct cgraph_node *node, bool cold)
1065 {
1066 bool has_hot_call = false;
1067
1068 /* Aliases gets inlined along with the function they alias. */
1069 if (node->alias)
1070 return false;
1071 /* Already inlined? */
1072 if (node->global.inlined_to)
1073 return false;
1074 /* Does it have callers? */
1075 if (!node->call_for_symbol_and_aliases (has_caller_p, NULL, true))
1076 return false;
1077 /* Inlining into all callers would increase size? */
1078 if (estimate_growth (node) > 0)
1079 return false;
1080 /* All inlines must be possible. */
1081 if (node->call_for_symbol_and_aliases (check_callers, &has_hot_call,
1082 true))
1083 return false;
1084 if (!cold && !has_hot_call)
1085 return false;
1086 return true;
1087 }
1088
1089 /* A cost model driving the inlining heuristics in a way so the edges with
1090 smallest badness are inlined first. After each inlining is performed
1091 the costs of all caller edges of nodes affected are recomputed so the
1092 metrics may accurately depend on values such as number of inlinable callers
1093 of the function or function body size. */
1094
1095 static sreal
1096 edge_badness (struct cgraph_edge *edge, bool dump)
1097 {
1098 sreal badness;
1099 int growth;
1100 sreal edge_time, unspec_edge_time;
1101 struct cgraph_node *callee = edge->callee->ultimate_alias_target ();
1102 class ipa_fn_summary *callee_info = ipa_fn_summaries->get (callee);
1103 ipa_hints hints;
1104 cgraph_node *caller = (edge->caller->global.inlined_to
1105 ? edge->caller->global.inlined_to
1106 : edge->caller);
1107
1108 growth = estimate_edge_growth (edge);
1109 edge_time = estimate_edge_time (edge, &unspec_edge_time);
1110 hints = estimate_edge_hints (edge);
1111 gcc_checking_assert (edge_time >= 0);
1112 /* Check that inlined time is better, but tolerate some roundoff issues.
1113 FIXME: When callee profile drops to 0 we account calls more. This
1114 should be fixed by never doing that. */
1115 gcc_checking_assert ((edge_time * 100
1116 - callee_info->time * 101).to_int () <= 0
1117 || callee->count.ipa ().initialized_p ());
1118 gcc_checking_assert (growth <= callee_info->size);
1119
1120 if (dump)
1121 {
1122 fprintf (dump_file, " Badness calculation for %s -> %s\n",
1123 edge->caller->dump_name (),
1124 edge->callee->dump_name ());
1125 fprintf (dump_file, " size growth %i, time %f unspec %f ",
1126 growth,
1127 edge_time.to_double (),
1128 unspec_edge_time.to_double ());
1129 ipa_dump_hints (dump_file, hints);
1130 if (big_speedup_p (edge))
1131 fprintf (dump_file, " big_speedup");
1132 fprintf (dump_file, "\n");
1133 }
1134
1135 /* Always prefer inlining saving code size. */
1136 if (growth <= 0)
1137 {
1138 badness = (sreal) (-SREAL_MIN_SIG + growth) << (SREAL_MAX_EXP / 256);
1139 if (dump)
1140 fprintf (dump_file, " %f: Growth %d <= 0\n", badness.to_double (),
1141 growth);
1142 }
1143 /* Inlining into EXTERNAL functions is not going to change anything unless
1144 they are themselves inlined. */
1145 else if (DECL_EXTERNAL (caller->decl))
1146 {
1147 if (dump)
1148 fprintf (dump_file, " max: function is external\n");
1149 return sreal::max ();
1150 }
1151 /* When profile is available. Compute badness as:
1152
1153 time_saved * caller_count
1154 goodness = -------------------------------------------------
1155 growth_of_caller * overall_growth * combined_size
1156
1157 badness = - goodness
1158
1159 Again use negative value to make calls with profile appear hotter
1160 then calls without.
1161 */
1162 else if (opt_for_fn (caller->decl, flag_guess_branch_prob)
1163 || caller->count.ipa ().nonzero_p ())
1164 {
1165 sreal numerator, denominator;
1166 int overall_growth;
1167 sreal inlined_time = compute_inlined_call_time (edge, edge_time);
1168
1169 numerator = (compute_uninlined_call_time (edge, unspec_edge_time)
1170 - inlined_time);
1171 if (numerator <= 0)
1172 numerator = ((sreal) 1 >> 8);
1173 if (caller->count.ipa ().nonzero_p ())
1174 numerator *= caller->count.ipa ().to_gcov_type ();
1175 else if (caller->count.ipa ().initialized_p ())
1176 numerator = numerator >> 11;
1177 denominator = growth;
1178
1179 overall_growth = callee_info->growth;
1180
1181 /* Look for inliner wrappers of the form:
1182
1183 inline_caller ()
1184 {
1185 do_fast_job...
1186 if (need_more_work)
1187 noninline_callee ();
1188 }
1189 Withhout penalizing this case, we usually inline noninline_callee
1190 into the inline_caller because overall_growth is small preventing
1191 further inlining of inline_caller.
1192
1193 Penalize only callgraph edges to functions with small overall
1194 growth ...
1195 */
1196 if (growth > overall_growth
1197 /* ... and having only one caller which is not inlined ... */
1198 && callee_info->single_caller
1199 && !edge->caller->global.inlined_to
1200 /* ... and edges executed only conditionally ... */
1201 && edge->sreal_frequency () < 1
1202 /* ... consider case where callee is not inline but caller is ... */
1203 && ((!DECL_DECLARED_INLINE_P (edge->callee->decl)
1204 && DECL_DECLARED_INLINE_P (caller->decl))
1205 /* ... or when early optimizers decided to split and edge
1206 frequency still indicates splitting is a win ... */
1207 || (callee->split_part && !caller->split_part
1208 && edge->sreal_frequency () * 100
1209 < PARAM_VALUE
1210 (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY)
1211 /* ... and do not overwrite user specified hints. */
1212 && (!DECL_DECLARED_INLINE_P (edge->callee->decl)
1213 || DECL_DECLARED_INLINE_P (caller->decl)))))
1214 {
1215 ipa_fn_summary *caller_info = ipa_fn_summaries->get (caller);
1216 int caller_growth = caller_info->growth;
1217
1218 /* Only apply the penalty when caller looks like inline candidate,
1219 and it is not called once. */
1220 if (!caller_info->single_caller && overall_growth < caller_growth
1221 && caller_info->inlinable
1222 && caller_info->size
1223 < (DECL_DECLARED_INLINE_P (caller->decl)
1224 ? inline_insns_single (caller, false)
1225 : inline_insns_auto (caller, false)))
1226 {
1227 if (dump)
1228 fprintf (dump_file,
1229 " Wrapper penalty. Increasing growth %i to %i\n",
1230 overall_growth, caller_growth);
1231 overall_growth = caller_growth;
1232 }
1233 }
1234 if (overall_growth > 0)
1235 {
1236 /* Strongly preffer functions with few callers that can be inlined
1237 fully. The square root here leads to smaller binaries at average.
1238 Watch however for extreme cases and return to linear function
1239 when growth is large. */
1240 if (overall_growth < 256)
1241 overall_growth *= overall_growth;
1242 else
1243 overall_growth += 256 * 256 - 256;
1244 denominator *= overall_growth;
1245 }
1246 denominator *= ipa_fn_summaries->get (caller)->size + growth;
1247
1248 badness = - numerator / denominator;
1249
1250 if (dump)
1251 {
1252 fprintf (dump_file,
1253 " %f: guessed profile. frequency %f, count %" PRId64
1254 " caller count %" PRId64
1255 " time w/o inlining %f, time with inlining %f"
1256 " overall growth %i (current) %i (original)"
1257 " %i (compensated)\n",
1258 badness.to_double (),
1259 edge->sreal_frequency ().to_double (),
1260 edge->count.ipa ().initialized_p () ? edge->count.ipa ().to_gcov_type () : -1,
1261 caller->count.ipa ().initialized_p () ? caller->count.ipa ().to_gcov_type () : -1,
1262 compute_uninlined_call_time (edge,
1263 unspec_edge_time).to_double (),
1264 inlined_time.to_double (),
1265 estimate_growth (callee),
1266 callee_info->growth, overall_growth);
1267 }
1268 }
1269 /* When function local profile is not available or it does not give
1270 useful information (ie frequency is zero), base the cost on
1271 loop nest and overall size growth, so we optimize for overall number
1272 of functions fully inlined in program. */
1273 else
1274 {
1275 int nest = MIN (ipa_call_summaries->get (edge)->loop_depth, 8);
1276 badness = growth;
1277
1278 /* Decrease badness if call is nested. */
1279 if (badness > 0)
1280 badness = badness >> nest;
1281 else
1282 badness = badness << nest;
1283 if (dump)
1284 fprintf (dump_file, " %f: no profile. nest %i\n",
1285 badness.to_double (), nest);
1286 }
1287 gcc_checking_assert (badness != 0);
1288
1289 if (edge->recursive_p ())
1290 badness = badness.shift (badness > 0 ? 4 : -4);
1291 if ((hints & (INLINE_HINT_indirect_call
1292 | INLINE_HINT_loop_iterations
1293 | INLINE_HINT_loop_stride))
1294 || callee_info->growth <= 0)
1295 badness = badness.shift (badness > 0 ? -2 : 2);
1296 if (hints & (INLINE_HINT_same_scc))
1297 badness = badness.shift (badness > 0 ? 3 : -3);
1298 else if (hints & (INLINE_HINT_in_scc))
1299 badness = badness.shift (badness > 0 ? 2 : -2);
1300 else if (hints & (INLINE_HINT_cross_module))
1301 badness = badness.shift (badness > 0 ? 1 : -1);
1302 if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
1303 badness = badness.shift (badness > 0 ? -4 : 4);
1304 else if ((hints & INLINE_HINT_declared_inline))
1305 badness = badness.shift (badness > 0 ? -3 : 3);
1306 if (dump)
1307 fprintf (dump_file, " Adjusted by hints %f\n", badness.to_double ());
1308 return badness;
1309 }
1310
1311 /* Recompute badness of EDGE and update its key in HEAP if needed. */
1312 static inline void
1313 update_edge_key (edge_heap_t *heap, struct cgraph_edge *edge)
1314 {
1315 sreal badness = edge_badness (edge, false);
1316 if (edge->aux)
1317 {
1318 edge_heap_node_t *n = (edge_heap_node_t *) edge->aux;
1319 gcc_checking_assert (n->get_data () == edge);
1320
1321 /* fibonacci_heap::replace_key does busy updating of the
1322 heap that is unnecesarily expensive.
1323 We do lazy increases: after extracting minimum if the key
1324 turns out to be out of date, it is re-inserted into heap
1325 with correct value. */
1326 if (badness < n->get_key ())
1327 {
1328 if (dump_file && (dump_flags & TDF_DETAILS))
1329 {
1330 fprintf (dump_file,
1331 " decreasing badness %s -> %s, %f to %f\n",
1332 edge->caller->dump_name (),
1333 edge->callee->dump_name (),
1334 n->get_key ().to_double (),
1335 badness.to_double ());
1336 }
1337 heap->decrease_key (n, badness);
1338 }
1339 }
1340 else
1341 {
1342 if (dump_file && (dump_flags & TDF_DETAILS))
1343 {
1344 fprintf (dump_file,
1345 " enqueuing call %s -> %s, badness %f\n",
1346 edge->caller->dump_name (),
1347 edge->callee->dump_name (),
1348 badness.to_double ());
1349 }
1350 edge->aux = heap->insert (badness, edge);
1351 }
1352 }
1353
1354
1355 /* NODE was inlined.
1356 All caller edges needs to be resetted because
1357 size estimates change. Similarly callees needs reset
1358 because better context may be known. */
1359
1360 static void
1361 reset_edge_caches (struct cgraph_node *node)
1362 {
1363 struct cgraph_edge *edge;
1364 struct cgraph_edge *e = node->callees;
1365 struct cgraph_node *where = node;
1366 struct ipa_ref *ref;
1367
1368 if (where->global.inlined_to)
1369 where = where->global.inlined_to;
1370
1371 if (edge_growth_cache != NULL)
1372 for (edge = where->callers; edge; edge = edge->next_caller)
1373 if (edge->inline_failed)
1374 edge_growth_cache->remove (edge);
1375
1376 FOR_EACH_ALIAS (where, ref)
1377 reset_edge_caches (dyn_cast <cgraph_node *> (ref->referring));
1378
1379 if (!e)
1380 return;
1381
1382 while (true)
1383 if (!e->inline_failed && e->callee->callees)
1384 e = e->callee->callees;
1385 else
1386 {
1387 if (edge_growth_cache != NULL && e->inline_failed)
1388 edge_growth_cache->remove (e);
1389 if (e->next_callee)
1390 e = e->next_callee;
1391 else
1392 {
1393 do
1394 {
1395 if (e->caller == node)
1396 return;
1397 e = e->caller->callers;
1398 }
1399 while (!e->next_callee);
1400 e = e->next_callee;
1401 }
1402 }
1403 }
1404
1405 /* Recompute HEAP nodes for each of caller of NODE.
1406 UPDATED_NODES track nodes we already visited, to avoid redundant work.
1407 When CHECK_INLINABLITY_FOR is set, re-check for specified edge that
1408 it is inlinable. Otherwise check all edges. */
1409
1410 static void
1411 update_caller_keys (edge_heap_t *heap, struct cgraph_node *node,
1412 bitmap updated_nodes,
1413 struct cgraph_edge *check_inlinablity_for)
1414 {
1415 struct cgraph_edge *edge;
1416 struct ipa_ref *ref;
1417
1418 if ((!node->alias && !ipa_fn_summaries->get (node)->inlinable)
1419 || node->global.inlined_to)
1420 return;
1421 if (!bitmap_set_bit (updated_nodes, node->get_uid ()))
1422 return;
1423
1424 FOR_EACH_ALIAS (node, ref)
1425 {
1426 struct cgraph_node *alias = dyn_cast <cgraph_node *> (ref->referring);
1427 update_caller_keys (heap, alias, updated_nodes, check_inlinablity_for);
1428 }
1429
1430 for (edge = node->callers; edge; edge = edge->next_caller)
1431 if (edge->inline_failed)
1432 {
1433 if (!check_inlinablity_for
1434 || check_inlinablity_for == edge)
1435 {
1436 if (can_inline_edge_p (edge, false)
1437 && want_inline_small_function_p (edge, false)
1438 && can_inline_edge_by_limits_p (edge, false))
1439 update_edge_key (heap, edge);
1440 else if (edge->aux)
1441 {
1442 report_inline_failed_reason (edge);
1443 heap->delete_node ((edge_heap_node_t *) edge->aux);
1444 edge->aux = NULL;
1445 }
1446 }
1447 else if (edge->aux)
1448 update_edge_key (heap, edge);
1449 }
1450 }
1451
1452 /* Recompute HEAP nodes for each uninlined call in NODE.
1453 This is used when we know that edge badnesses are going only to increase
1454 (we introduced new call site) and thus all we need is to insert newly
1455 created edges into heap. */
1456
1457 static void
1458 update_callee_keys (edge_heap_t *heap, struct cgraph_node *node,
1459 bitmap updated_nodes)
1460 {
1461 struct cgraph_edge *e = node->callees;
1462
1463 if (!e)
1464 return;
1465 while (true)
1466 if (!e->inline_failed && e->callee->callees)
1467 e = e->callee->callees;
1468 else
1469 {
1470 enum availability avail;
1471 struct cgraph_node *callee;
1472 /* We do not reset callee growth cache here. Since we added a new call,
1473 growth chould have just increased and consequentely badness metric
1474 don't need updating. */
1475 if (e->inline_failed
1476 && (callee = e->callee->ultimate_alias_target (&avail, e->caller))
1477 && ipa_fn_summaries->get (callee) != NULL
1478 && ipa_fn_summaries->get (callee)->inlinable
1479 && avail >= AVAIL_AVAILABLE
1480 && !bitmap_bit_p (updated_nodes, callee->get_uid ()))
1481 {
1482 if (can_inline_edge_p (e, false)
1483 && want_inline_small_function_p (e, false)
1484 && can_inline_edge_by_limits_p (e, false))
1485 update_edge_key (heap, e);
1486 else if (e->aux)
1487 {
1488 report_inline_failed_reason (e);
1489 heap->delete_node ((edge_heap_node_t *) e->aux);
1490 e->aux = NULL;
1491 }
1492 }
1493 if (e->next_callee)
1494 e = e->next_callee;
1495 else
1496 {
1497 do
1498 {
1499 if (e->caller == node)
1500 return;
1501 e = e->caller->callers;
1502 }
1503 while (!e->next_callee);
1504 e = e->next_callee;
1505 }
1506 }
1507 }
1508
1509 /* Enqueue all recursive calls from NODE into priority queue depending on
1510 how likely we want to recursively inline the call. */
1511
1512 static void
1513 lookup_recursive_calls (struct cgraph_node *node, struct cgraph_node *where,
1514 edge_heap_t *heap)
1515 {
1516 struct cgraph_edge *e;
1517 enum availability avail;
1518
1519 for (e = where->callees; e; e = e->next_callee)
1520 if (e->callee == node
1521 || (e->callee->ultimate_alias_target (&avail, e->caller) == node
1522 && avail > AVAIL_INTERPOSABLE))
1523 heap->insert (-e->sreal_frequency (), e);
1524 for (e = where->callees; e; e = e->next_callee)
1525 if (!e->inline_failed)
1526 lookup_recursive_calls (node, e->callee, heap);
1527 }
1528
1529 /* Decide on recursive inlining: in the case function has recursive calls,
1530 inline until body size reaches given argument. If any new indirect edges
1531 are discovered in the process, add them to *NEW_EDGES, unless NEW_EDGES
1532 is NULL. */
1533
1534 static bool
1535 recursive_inlining (struct cgraph_edge *edge,
1536 vec<cgraph_edge *> *new_edges)
1537 {
1538 int limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO);
1539 edge_heap_t heap (sreal::min ());
1540 struct cgraph_node *node;
1541 struct cgraph_edge *e;
1542 struct cgraph_node *master_clone = NULL, *next;
1543 int depth = 0;
1544 int n = 0;
1545
1546 node = edge->caller;
1547 if (node->global.inlined_to)
1548 node = node->global.inlined_to;
1549
1550 if (DECL_DECLARED_INLINE_P (node->decl))
1551 limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE);
1552
1553 /* Make sure that function is small enough to be considered for inlining. */
1554 if (estimate_size_after_inlining (node, edge) >= limit)
1555 return false;
1556 lookup_recursive_calls (node, node, &heap);
1557 if (heap.empty ())
1558 return false;
1559
1560 if (dump_file)
1561 fprintf (dump_file,
1562 " Performing recursive inlining on %s\n",
1563 node->name ());
1564
1565 /* Do the inlining and update list of recursive call during process. */
1566 while (!heap.empty ())
1567 {
1568 struct cgraph_edge *curr = heap.extract_min ();
1569 struct cgraph_node *cnode, *dest = curr->callee;
1570
1571 if (!can_inline_edge_p (curr, true)
1572 || !can_inline_edge_by_limits_p (curr, true))
1573 continue;
1574
1575 /* MASTER_CLONE is produced in the case we already started modified
1576 the function. Be sure to redirect edge to the original body before
1577 estimating growths otherwise we will be seeing growths after inlining
1578 the already modified body. */
1579 if (master_clone)
1580 {
1581 curr->redirect_callee (master_clone);
1582 if (edge_growth_cache != NULL)
1583 edge_growth_cache->remove (curr);
1584 }
1585
1586 if (estimate_size_after_inlining (node, curr) > limit)
1587 {
1588 curr->redirect_callee (dest);
1589 if (edge_growth_cache != NULL)
1590 edge_growth_cache->remove (curr);
1591 break;
1592 }
1593
1594 depth = 1;
1595 for (cnode = curr->caller;
1596 cnode->global.inlined_to; cnode = cnode->callers->caller)
1597 if (node->decl
1598 == curr->callee->ultimate_alias_target ()->decl)
1599 depth++;
1600
1601 if (!want_inline_self_recursive_call_p (curr, node, false, depth))
1602 {
1603 curr->redirect_callee (dest);
1604 if (edge_growth_cache != NULL)
1605 edge_growth_cache->remove (curr);
1606 continue;
1607 }
1608
1609 if (dump_file)
1610 {
1611 fprintf (dump_file,
1612 " Inlining call of depth %i", depth);
1613 if (node->count.nonzero_p () && curr->count.initialized_p ())
1614 {
1615 fprintf (dump_file, " called approx. %.2f times per call",
1616 (double)curr->count.to_gcov_type ()
1617 / node->count.to_gcov_type ());
1618 }
1619 fprintf (dump_file, "\n");
1620 }
1621 if (!master_clone)
1622 {
1623 /* We need original clone to copy around. */
1624 master_clone = node->create_clone (node->decl, node->count,
1625 false, vNULL, true, NULL, NULL);
1626 for (e = master_clone->callees; e; e = e->next_callee)
1627 if (!e->inline_failed)
1628 clone_inlined_nodes (e, true, false, NULL);
1629 curr->redirect_callee (master_clone);
1630 if (edge_growth_cache != NULL)
1631 edge_growth_cache->remove (curr);
1632 }
1633
1634 inline_call (curr, false, new_edges, &overall_size, true);
1635 lookup_recursive_calls (node, curr->callee, &heap);
1636 n++;
1637 }
1638
1639 if (!heap.empty () && dump_file)
1640 fprintf (dump_file, " Recursive inlining growth limit met.\n");
1641
1642 if (!master_clone)
1643 return false;
1644
1645 if (dump_enabled_p ())
1646 dump_printf_loc (MSG_NOTE, edge->call_stmt,
1647 "\n Inlined %i times, "
1648 "body grown from size %i to %i, time %f to %f\n", n,
1649 ipa_fn_summaries->get (master_clone)->size,
1650 ipa_fn_summaries->get (node)->size,
1651 ipa_fn_summaries->get (master_clone)->time.to_double (),
1652 ipa_fn_summaries->get (node)->time.to_double ());
1653
1654 /* Remove master clone we used for inlining. We rely that clones inlined
1655 into master clone gets queued just before master clone so we don't
1656 need recursion. */
1657 for (node = symtab->first_function (); node != master_clone;
1658 node = next)
1659 {
1660 next = symtab->next_function (node);
1661 if (node->global.inlined_to == master_clone)
1662 node->remove ();
1663 }
1664 master_clone->remove ();
1665 return true;
1666 }
1667
1668
1669 /* Given whole compilation unit estimate of INSNS, compute how large we can
1670 allow the unit to grow. */
1671
1672 static int
1673 compute_max_insns (int insns)
1674 {
1675 int max_insns = insns;
1676 if (max_insns < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS))
1677 max_insns = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS);
1678
1679 return ((int64_t) max_insns
1680 * (100 + PARAM_VALUE (PARAM_INLINE_UNIT_GROWTH)) / 100);
1681 }
1682
1683
1684 /* Compute badness of all edges in NEW_EDGES and add them to the HEAP. */
1685
1686 static void
1687 add_new_edges_to_heap (edge_heap_t *heap, vec<cgraph_edge *> new_edges)
1688 {
1689 while (new_edges.length () > 0)
1690 {
1691 struct cgraph_edge *edge = new_edges.pop ();
1692
1693 gcc_assert (!edge->aux);
1694 gcc_assert (edge->callee);
1695 if (edge->inline_failed
1696 && can_inline_edge_p (edge, true)
1697 && want_inline_small_function_p (edge, true)
1698 && can_inline_edge_by_limits_p (edge, true))
1699 edge->aux = heap->insert (edge_badness (edge, false), edge);
1700 }
1701 }
1702
1703 /* Remove EDGE from the fibheap. */
1704
1705 static void
1706 heap_edge_removal_hook (struct cgraph_edge *e, void *data)
1707 {
1708 if (e->aux)
1709 {
1710 ((edge_heap_t *)data)->delete_node ((edge_heap_node_t *)e->aux);
1711 e->aux = NULL;
1712 }
1713 }
1714
1715 /* Return true if speculation of edge E seems useful.
1716 If ANTICIPATE_INLINING is true, be conservative and hope that E
1717 may get inlined. */
1718
1719 bool
1720 speculation_useful_p (struct cgraph_edge *e, bool anticipate_inlining)
1721 {
1722 /* If we have already decided to inline the edge, it seems useful. */
1723 if (!e->inline_failed)
1724 return true;
1725
1726 enum availability avail;
1727 struct cgraph_node *target = e->callee->ultimate_alias_target (&avail,
1728 e->caller);
1729 struct cgraph_edge *direct, *indirect;
1730 struct ipa_ref *ref;
1731
1732 gcc_assert (e->speculative && !e->indirect_unknown_callee);
1733
1734 if (!e->maybe_hot_p ())
1735 return false;
1736
1737 /* See if IP optimizations found something potentially useful about the
1738 function. For now we look only for CONST/PURE flags. Almost everything
1739 else we propagate is useless. */
1740 if (avail >= AVAIL_AVAILABLE)
1741 {
1742 int ecf_flags = flags_from_decl_or_type (target->decl);
1743 if (ecf_flags & ECF_CONST)
1744 {
1745 e->speculative_call_info (direct, indirect, ref);
1746 if (!(indirect->indirect_info->ecf_flags & ECF_CONST))
1747 return true;
1748 }
1749 else if (ecf_flags & ECF_PURE)
1750 {
1751 e->speculative_call_info (direct, indirect, ref);
1752 if (!(indirect->indirect_info->ecf_flags & ECF_PURE))
1753 return true;
1754 }
1755 }
1756 /* If we did not managed to inline the function nor redirect
1757 to an ipa-cp clone (that are seen by having local flag set),
1758 it is probably pointless to inline it unless hardware is missing
1759 indirect call predictor. */
1760 if (!anticipate_inlining && !target->local.local)
1761 return false;
1762 /* For overwritable targets there is not much to do. */
1763 if (!can_inline_edge_p (e, false)
1764 || !can_inline_edge_by_limits_p (e, false, true))
1765 return false;
1766 /* OK, speculation seems interesting. */
1767 return true;
1768 }
1769
1770 /* We know that EDGE is not going to be inlined.
1771 See if we can remove speculation. */
1772
1773 static void
1774 resolve_noninline_speculation (edge_heap_t *edge_heap, struct cgraph_edge *edge)
1775 {
1776 if (edge->speculative && !speculation_useful_p (edge, false))
1777 {
1778 struct cgraph_node *node = edge->caller;
1779 struct cgraph_node *where = node->global.inlined_to
1780 ? node->global.inlined_to : node;
1781 auto_bitmap updated_nodes;
1782
1783 if (edge->count.ipa ().initialized_p ())
1784 spec_rem += edge->count.ipa ();
1785 edge->resolve_speculation ();
1786 reset_edge_caches (where);
1787 ipa_update_overall_fn_summary (where);
1788 update_caller_keys (edge_heap, where,
1789 updated_nodes, NULL);
1790 update_callee_keys (edge_heap, where,
1791 updated_nodes);
1792 }
1793 }
1794
1795 /* Return true if NODE should be accounted for overall size estimate.
1796 Skip all nodes optimized for size so we can measure the growth of hot
1797 part of program no matter of the padding. */
1798
1799 bool
1800 inline_account_function_p (struct cgraph_node *node)
1801 {
1802 return (!DECL_EXTERNAL (node->decl)
1803 && !opt_for_fn (node->decl, optimize_size)
1804 && node->frequency != NODE_FREQUENCY_UNLIKELY_EXECUTED);
1805 }
1806
1807 /* Count number of callers of NODE and store it into DATA (that
1808 points to int. Worker for cgraph_for_node_and_aliases. */
1809
1810 static bool
1811 sum_callers (struct cgraph_node *node, void *data)
1812 {
1813 struct cgraph_edge *e;
1814 int *num_calls = (int *)data;
1815
1816 for (e = node->callers; e; e = e->next_caller)
1817 (*num_calls)++;
1818 return false;
1819 }
1820
1821 /* We only propagate across edges with non-interposable callee. */
1822
1823 inline bool
1824 ignore_edge_p (struct cgraph_edge *e)
1825 {
1826 enum availability avail;
1827 e->callee->function_or_virtual_thunk_symbol (&avail, e->caller);
1828 return (avail <= AVAIL_INTERPOSABLE);
1829 }
1830
1831 /* We use greedy algorithm for inlining of small functions:
1832 All inline candidates are put into prioritized heap ordered in
1833 increasing badness.
1834
1835 The inlining of small functions is bounded by unit growth parameters. */
1836
1837 static void
1838 inline_small_functions (void)
1839 {
1840 struct cgraph_node *node;
1841 struct cgraph_edge *edge;
1842 edge_heap_t edge_heap (sreal::min ());
1843 auto_bitmap updated_nodes;
1844 int min_size, max_size;
1845 auto_vec<cgraph_edge *> new_indirect_edges;
1846 int initial_size = 0;
1847 struct cgraph_node **order = XCNEWVEC (cgraph_node *, symtab->cgraph_count);
1848 struct cgraph_edge_hook_list *edge_removal_hook_holder;
1849 new_indirect_edges.create (8);
1850
1851 edge_removal_hook_holder
1852 = symtab->add_edge_removal_hook (&heap_edge_removal_hook, &edge_heap);
1853
1854 /* Compute overall unit size and other global parameters used by badness
1855 metrics. */
1856
1857 max_count = profile_count::uninitialized ();
1858 ipa_reduced_postorder (order, true, ignore_edge_p);
1859 free (order);
1860
1861 FOR_EACH_DEFINED_FUNCTION (node)
1862 if (!node->global.inlined_to)
1863 {
1864 if (!node->alias && node->analyzed
1865 && (node->has_gimple_body_p () || node->thunk.thunk_p)
1866 && opt_for_fn (node->decl, optimize))
1867 {
1868 class ipa_fn_summary *info = ipa_fn_summaries->get (node);
1869 struct ipa_dfs_info *dfs = (struct ipa_dfs_info *) node->aux;
1870
1871 /* Do not account external functions, they will be optimized out
1872 if not inlined. Also only count the non-cold portion of program. */
1873 if (inline_account_function_p (node))
1874 initial_size += info->size;
1875 info->growth = estimate_growth (node);
1876
1877 int num_calls = 0;
1878 node->call_for_symbol_and_aliases (sum_callers, &num_calls,
1879 true);
1880 if (num_calls == 1)
1881 info->single_caller = true;
1882 if (dfs && dfs->next_cycle)
1883 {
1884 struct cgraph_node *n2;
1885 int id = dfs->scc_no + 1;
1886 for (n2 = node; n2;
1887 n2 = ((struct ipa_dfs_info *) n2->aux)->next_cycle)
1888 if (opt_for_fn (n2->decl, optimize))
1889 {
1890 ipa_fn_summary *info2 = ipa_fn_summaries->get (n2);
1891 if (info2->scc_no)
1892 break;
1893 info2->scc_no = id;
1894 }
1895 }
1896 }
1897
1898 for (edge = node->callers; edge; edge = edge->next_caller)
1899 max_count = max_count.max (edge->count.ipa ());
1900 }
1901 ipa_free_postorder_info ();
1902 edge_growth_cache
1903 = new call_summary<edge_growth_cache_entry *> (symtab, false);
1904
1905 if (dump_file)
1906 fprintf (dump_file,
1907 "\nDeciding on inlining of small functions. Starting with size %i.\n",
1908 initial_size);
1909
1910 overall_size = initial_size;
1911 max_size = compute_max_insns (overall_size);
1912 min_size = overall_size;
1913
1914 /* Populate the heap with all edges we might inline. */
1915
1916 FOR_EACH_DEFINED_FUNCTION (node)
1917 {
1918 bool update = false;
1919 struct cgraph_edge *next = NULL;
1920 bool has_speculative = false;
1921
1922 if (!opt_for_fn (node->decl, optimize))
1923 continue;
1924
1925 if (dump_file)
1926 fprintf (dump_file, "Enqueueing calls in %s.\n", node->dump_name ());
1927
1928 for (edge = node->callees; edge; edge = next)
1929 {
1930 next = edge->next_callee;
1931 if (edge->inline_failed
1932 && !edge->aux
1933 && can_inline_edge_p (edge, true)
1934 && want_inline_small_function_p (edge, true)
1935 && can_inline_edge_by_limits_p (edge, true)
1936 && edge->inline_failed)
1937 {
1938 gcc_assert (!edge->aux);
1939 update_edge_key (&edge_heap, edge);
1940 }
1941 if (edge->speculative)
1942 has_speculative = true;
1943 }
1944 if (has_speculative)
1945 for (edge = node->callees; edge; edge = next)
1946 if (edge->speculative && !speculation_useful_p (edge,
1947 edge->aux != NULL))
1948 {
1949 edge->resolve_speculation ();
1950 update = true;
1951 }
1952 if (update)
1953 {
1954 struct cgraph_node *where = node->global.inlined_to
1955 ? node->global.inlined_to : node;
1956 ipa_update_overall_fn_summary (where);
1957 reset_edge_caches (where);
1958 update_caller_keys (&edge_heap, where,
1959 updated_nodes, NULL);
1960 update_callee_keys (&edge_heap, where,
1961 updated_nodes);
1962 bitmap_clear (updated_nodes);
1963 }
1964 }
1965
1966 gcc_assert (in_lto_p
1967 || !(max_count > 0)
1968 || (profile_info && flag_branch_probabilities));
1969
1970 while (!edge_heap.empty ())
1971 {
1972 int old_size = overall_size;
1973 struct cgraph_node *where, *callee;
1974 sreal badness = edge_heap.min_key ();
1975 sreal current_badness;
1976 int growth;
1977
1978 edge = edge_heap.extract_min ();
1979 gcc_assert (edge->aux);
1980 edge->aux = NULL;
1981 if (!edge->inline_failed || !edge->callee->analyzed)
1982 continue;
1983
1984 #if CHECKING_P
1985 /* Be sure that caches are maintained consistent.
1986 This check is affected by scaling roundoff errors when compiling for
1987 IPA this we skip it in that case. */
1988 if (!edge->callee->count.ipa_p ()
1989 && (!max_count.initialized_p () || !max_count.nonzero_p ()))
1990 {
1991 sreal cached_badness = edge_badness (edge, false);
1992
1993 int old_size_est = estimate_edge_size (edge);
1994 sreal old_time_est = estimate_edge_time (edge);
1995 int old_hints_est = estimate_edge_hints (edge);
1996
1997 if (edge_growth_cache != NULL)
1998 edge_growth_cache->remove (edge);
1999 gcc_assert (old_size_est == estimate_edge_size (edge));
2000 gcc_assert (old_time_est == estimate_edge_time (edge));
2001 /* FIXME:
2002
2003 gcc_assert (old_hints_est == estimate_edge_hints (edge));
2004
2005 fails with profile feedback because some hints depends on
2006 maybe_hot_edge_p predicate and because callee gets inlined to other
2007 calls, the edge may become cold.
2008 This ought to be fixed by computing relative probabilities
2009 for given invocation but that will be better done once whole
2010 code is converted to sreals. Disable for now and revert to "wrong"
2011 value so enable/disable checking paths agree. */
2012 edge_growth_cache->get (edge)->hints = old_hints_est + 1;
2013
2014 /* When updating the edge costs, we only decrease badness in the keys.
2015 Increases of badness are handled lazilly; when we see key with out
2016 of date value on it, we re-insert it now. */
2017 current_badness = edge_badness (edge, false);
2018 gcc_assert (cached_badness == current_badness);
2019 gcc_assert (current_badness >= badness);
2020 }
2021 else
2022 current_badness = edge_badness (edge, false);
2023 #else
2024 current_badness = edge_badness (edge, false);
2025 #endif
2026 if (current_badness != badness)
2027 {
2028 if (edge_heap.min () && current_badness > edge_heap.min_key ())
2029 {
2030 edge->aux = edge_heap.insert (current_badness, edge);
2031 continue;
2032 }
2033 else
2034 badness = current_badness;
2035 }
2036
2037 if (!can_inline_edge_p (edge, true)
2038 || !can_inline_edge_by_limits_p (edge, true))
2039 {
2040 resolve_noninline_speculation (&edge_heap, edge);
2041 continue;
2042 }
2043
2044 callee = edge->callee->ultimate_alias_target ();
2045 growth = estimate_edge_growth (edge);
2046 if (dump_file)
2047 {
2048 fprintf (dump_file,
2049 "\nConsidering %s with %i size\n",
2050 callee->dump_name (),
2051 ipa_fn_summaries->get (callee)->size);
2052 fprintf (dump_file,
2053 " to be inlined into %s in %s:%i\n"
2054 " Estimated badness is %f, frequency %.2f.\n",
2055 edge->caller->dump_name (),
2056 edge->call_stmt
2057 && (LOCATION_LOCUS (gimple_location ((const gimple *)
2058 edge->call_stmt))
2059 > BUILTINS_LOCATION)
2060 ? gimple_filename ((const gimple *) edge->call_stmt)
2061 : "unknown",
2062 edge->call_stmt
2063 ? gimple_lineno ((const gimple *) edge->call_stmt)
2064 : -1,
2065 badness.to_double (),
2066 edge->sreal_frequency ().to_double ());
2067 if (edge->count.ipa ().initialized_p ())
2068 {
2069 fprintf (dump_file, " Called ");
2070 edge->count.ipa ().dump (dump_file);
2071 fprintf (dump_file, " times\n");
2072 }
2073 if (dump_flags & TDF_DETAILS)
2074 edge_badness (edge, true);
2075 }
2076
2077 if (overall_size + growth > max_size
2078 && !DECL_DISREGARD_INLINE_LIMITS (callee->decl))
2079 {
2080 edge->inline_failed = CIF_INLINE_UNIT_GROWTH_LIMIT;
2081 report_inline_failed_reason (edge);
2082 resolve_noninline_speculation (&edge_heap, edge);
2083 continue;
2084 }
2085
2086 if (!want_inline_small_function_p (edge, true))
2087 {
2088 resolve_noninline_speculation (&edge_heap, edge);
2089 continue;
2090 }
2091
2092 /* Heuristics for inlining small functions work poorly for
2093 recursive calls where we do effects similar to loop unrolling.
2094 When inlining such edge seems profitable, leave decision on
2095 specific inliner. */
2096 if (edge->recursive_p ())
2097 {
2098 where = edge->caller;
2099 if (where->global.inlined_to)
2100 where = where->global.inlined_to;
2101 if (!recursive_inlining (edge,
2102 opt_for_fn (edge->caller->decl,
2103 flag_indirect_inlining)
2104 ? &new_indirect_edges : NULL))
2105 {
2106 edge->inline_failed = CIF_RECURSIVE_INLINING;
2107 resolve_noninline_speculation (&edge_heap, edge);
2108 continue;
2109 }
2110 reset_edge_caches (where);
2111 /* Recursive inliner inlines all recursive calls of the function
2112 at once. Consequently we need to update all callee keys. */
2113 if (opt_for_fn (edge->caller->decl, flag_indirect_inlining))
2114 add_new_edges_to_heap (&edge_heap, new_indirect_edges);
2115 update_callee_keys (&edge_heap, where, updated_nodes);
2116 bitmap_clear (updated_nodes);
2117 }
2118 else
2119 {
2120 struct cgraph_node *outer_node = NULL;
2121 int depth = 0;
2122
2123 /* Consider the case where self recursive function A is inlined
2124 into B. This is desired optimization in some cases, since it
2125 leads to effect similar of loop peeling and we might completely
2126 optimize out the recursive call. However we must be extra
2127 selective. */
2128
2129 where = edge->caller;
2130 while (where->global.inlined_to)
2131 {
2132 if (where->decl == callee->decl)
2133 outer_node = where, depth++;
2134 where = where->callers->caller;
2135 }
2136 if (outer_node
2137 && !want_inline_self_recursive_call_p (edge, outer_node,
2138 true, depth))
2139 {
2140 edge->inline_failed
2141 = (DECL_DISREGARD_INLINE_LIMITS (edge->callee->decl)
2142 ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED);
2143 resolve_noninline_speculation (&edge_heap, edge);
2144 continue;
2145 }
2146 else if (depth && dump_file)
2147 fprintf (dump_file, " Peeling recursion with depth %i\n", depth);
2148
2149 gcc_checking_assert (!callee->global.inlined_to);
2150 inline_call (edge, true, &new_indirect_edges, &overall_size, true);
2151 add_new_edges_to_heap (&edge_heap, new_indirect_edges);
2152
2153 reset_edge_caches (edge->callee);
2154
2155 update_callee_keys (&edge_heap, where, updated_nodes);
2156 }
2157 where = edge->caller;
2158 if (where->global.inlined_to)
2159 where = where->global.inlined_to;
2160
2161 /* Our profitability metric can depend on local properties
2162 such as number of inlinable calls and size of the function body.
2163 After inlining these properties might change for the function we
2164 inlined into (since it's body size changed) and for the functions
2165 called by function we inlined (since number of it inlinable callers
2166 might change). */
2167 update_caller_keys (&edge_heap, where, updated_nodes, NULL);
2168 /* Offline copy count has possibly changed, recompute if profile is
2169 available. */
2170 struct cgraph_node *n = cgraph_node::get (edge->callee->decl);
2171 if (n != edge->callee && n->analyzed && n->count.ipa ().initialized_p ())
2172 update_callee_keys (&edge_heap, n, updated_nodes);
2173 bitmap_clear (updated_nodes);
2174
2175 if (dump_enabled_p ())
2176 {
2177 ipa_fn_summary *s = ipa_fn_summaries->get (edge->caller);
2178
2179 /* dump_printf can't handle %+i. */
2180 char buf_net_change[100];
2181 snprintf (buf_net_change, sizeof buf_net_change, "%+i",
2182 overall_size - old_size);
2183
2184 dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, edge->call_stmt,
2185 " Inlined %C into %C which now has time %f and "
2186 "size %i, net change of %s.\n",
2187 edge->callee, edge->caller,
2188 s->time.to_double (), s->size, buf_net_change);
2189 }
2190 if (min_size > overall_size)
2191 {
2192 min_size = overall_size;
2193 max_size = compute_max_insns (min_size);
2194
2195 if (dump_file)
2196 fprintf (dump_file, "New minimal size reached: %i\n", min_size);
2197 }
2198 }
2199
2200 free_growth_caches ();
2201 if (dump_enabled_p ())
2202 dump_printf (MSG_NOTE,
2203 "Unit growth for small function inlining: %i->%i (%i%%)\n",
2204 initial_size, overall_size,
2205 initial_size ? overall_size * 100 / (initial_size) - 100: 0);
2206 symtab->remove_edge_removal_hook (edge_removal_hook_holder);
2207 }
2208
2209 /* Flatten NODE. Performed both during early inlining and
2210 at IPA inlining time. */
2211
2212 static void
2213 flatten_function (struct cgraph_node *node, bool early, bool update)
2214 {
2215 struct cgraph_edge *e;
2216
2217 /* We shouldn't be called recursively when we are being processed. */
2218 gcc_assert (node->aux == NULL);
2219
2220 node->aux = (void *) node;
2221
2222 for (e = node->callees; e; e = e->next_callee)
2223 {
2224 struct cgraph_node *orig_callee;
2225 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
2226
2227 /* We've hit cycle? It is time to give up. */
2228 if (callee->aux)
2229 {
2230 if (dump_enabled_p ())
2231 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
2232 "Not inlining %C into %C to avoid cycle.\n",
2233 callee, e->caller);
2234 if (cgraph_inline_failed_type (e->inline_failed) != CIF_FINAL_ERROR)
2235 e->inline_failed = CIF_RECURSIVE_INLINING;
2236 continue;
2237 }
2238
2239 /* When the edge is already inlined, we just need to recurse into
2240 it in order to fully flatten the leaves. */
2241 if (!e->inline_failed)
2242 {
2243 flatten_function (callee, early, false);
2244 continue;
2245 }
2246
2247 /* Flatten attribute needs to be processed during late inlining. For
2248 extra code quality we however do flattening during early optimization,
2249 too. */
2250 if (!early
2251 ? !can_inline_edge_p (e, true)
2252 && !can_inline_edge_by_limits_p (e, true)
2253 : !can_early_inline_edge_p (e))
2254 continue;
2255
2256 if (e->recursive_p ())
2257 {
2258 if (dump_enabled_p ())
2259 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
2260 "Not inlining: recursive call.\n");
2261 continue;
2262 }
2263
2264 if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node->decl))
2265 != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->decl)))
2266 {
2267 if (dump_enabled_p ())
2268 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
2269 "Not inlining: SSA form does not match.\n");
2270 continue;
2271 }
2272
2273 /* Inline the edge and flatten the inline clone. Avoid
2274 recursing through the original node if the node was cloned. */
2275 if (dump_enabled_p ())
2276 dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, e->call_stmt,
2277 " Inlining %C into %C.\n",
2278 callee, e->caller);
2279 orig_callee = callee;
2280 inline_call (e, true, NULL, NULL, false);
2281 if (e->callee != orig_callee)
2282 orig_callee->aux = (void *) node;
2283 flatten_function (e->callee, early, false);
2284 if (e->callee != orig_callee)
2285 orig_callee->aux = NULL;
2286 }
2287
2288 node->aux = NULL;
2289 if (update)
2290 ipa_update_overall_fn_summary (node->global.inlined_to
2291 ? node->global.inlined_to : node);
2292 }
2293
2294 /* Inline NODE to all callers. Worker for cgraph_for_node_and_aliases.
2295 DATA points to number of calls originally found so we avoid infinite
2296 recursion. */
2297
2298 static bool
2299 inline_to_all_callers_1 (struct cgraph_node *node, void *data,
2300 hash_set<cgraph_node *> *callers)
2301 {
2302 int *num_calls = (int *)data;
2303 bool callee_removed = false;
2304
2305 while (node->callers && !node->global.inlined_to)
2306 {
2307 struct cgraph_node *caller = node->callers->caller;
2308
2309 if (!can_inline_edge_p (node->callers, true)
2310 || !can_inline_edge_by_limits_p (node->callers, true)
2311 || node->callers->recursive_p ())
2312 {
2313 if (dump_file)
2314 fprintf (dump_file, "Uninlinable call found; giving up.\n");
2315 *num_calls = 0;
2316 return false;
2317 }
2318
2319 if (dump_file)
2320 {
2321 cgraph_node *ultimate = node->ultimate_alias_target ();
2322 fprintf (dump_file,
2323 "\nInlining %s size %i.\n",
2324 ultimate->name (),
2325 ipa_fn_summaries->get (ultimate)->size);
2326 fprintf (dump_file,
2327 " Called once from %s %i insns.\n",
2328 node->callers->caller->name (),
2329 ipa_fn_summaries->get (node->callers->caller)->size);
2330 }
2331
2332 /* Remember which callers we inlined to, delaying updating the
2333 overall summary. */
2334 callers->add (node->callers->caller);
2335 inline_call (node->callers, true, NULL, NULL, false, &callee_removed);
2336 if (dump_file)
2337 fprintf (dump_file,
2338 " Inlined into %s which now has %i size\n",
2339 caller->name (),
2340 ipa_fn_summaries->get (caller)->size);
2341 if (!(*num_calls)--)
2342 {
2343 if (dump_file)
2344 fprintf (dump_file, "New calls found; giving up.\n");
2345 return callee_removed;
2346 }
2347 if (callee_removed)
2348 return true;
2349 }
2350 return false;
2351 }
2352
2353 /* Wrapper around inline_to_all_callers_1 doing delayed overall summary
2354 update. */
2355
2356 static bool
2357 inline_to_all_callers (struct cgraph_node *node, void *data)
2358 {
2359 hash_set<cgraph_node *> callers;
2360 bool res = inline_to_all_callers_1 (node, data, &callers);
2361 /* Perform the delayed update of the overall summary of all callers
2362 processed. This avoids quadratic behavior in the cases where
2363 we have a lot of calls to the same function. */
2364 for (hash_set<cgraph_node *>::iterator i = callers.begin ();
2365 i != callers.end (); ++i)
2366 ipa_update_overall_fn_summary (*i);
2367 return res;
2368 }
2369
2370 /* Output overall time estimate. */
2371 static void
2372 dump_overall_stats (void)
2373 {
2374 sreal sum_weighted = 0, sum = 0;
2375 struct cgraph_node *node;
2376
2377 FOR_EACH_DEFINED_FUNCTION (node)
2378 if (!node->global.inlined_to
2379 && !node->alias)
2380 {
2381 ipa_fn_summary *s = ipa_fn_summaries->get (node);
2382 if (s != NULL)
2383 {
2384 sum += s->time;
2385 if (node->count.ipa ().initialized_p ())
2386 sum_weighted += s->time * node->count.ipa ().to_gcov_type ();
2387 }
2388 }
2389 fprintf (dump_file, "Overall time estimate: "
2390 "%f weighted by profile: "
2391 "%f\n", sum.to_double (), sum_weighted.to_double ());
2392 }
2393
2394 /* Output some useful stats about inlining. */
2395
2396 static void
2397 dump_inline_stats (void)
2398 {
2399 int64_t inlined_cnt = 0, inlined_indir_cnt = 0;
2400 int64_t inlined_virt_cnt = 0, inlined_virt_indir_cnt = 0;
2401 int64_t noninlined_cnt = 0, noninlined_indir_cnt = 0;
2402 int64_t noninlined_virt_cnt = 0, noninlined_virt_indir_cnt = 0;
2403 int64_t inlined_speculative = 0, inlined_speculative_ply = 0;
2404 int64_t indirect_poly_cnt = 0, indirect_cnt = 0;
2405 int64_t reason[CIF_N_REASONS][2];
2406 sreal reason_freq[CIF_N_REASONS];
2407 int i;
2408 struct cgraph_node *node;
2409
2410 memset (reason, 0, sizeof (reason));
2411 for (i=0; i < CIF_N_REASONS; i++)
2412 reason_freq[i] = 0;
2413 FOR_EACH_DEFINED_FUNCTION (node)
2414 {
2415 struct cgraph_edge *e;
2416 for (e = node->callees; e; e = e->next_callee)
2417 {
2418 if (e->inline_failed)
2419 {
2420 if (e->count.ipa ().initialized_p ())
2421 reason[(int) e->inline_failed][0] += e->count.ipa ().to_gcov_type ();
2422 reason_freq[(int) e->inline_failed] += e->sreal_frequency ();
2423 reason[(int) e->inline_failed][1] ++;
2424 if (DECL_VIRTUAL_P (e->callee->decl)
2425 && e->count.ipa ().initialized_p ())
2426 {
2427 if (e->indirect_inlining_edge)
2428 noninlined_virt_indir_cnt += e->count.ipa ().to_gcov_type ();
2429 else
2430 noninlined_virt_cnt += e->count.ipa ().to_gcov_type ();
2431 }
2432 else if (e->count.ipa ().initialized_p ())
2433 {
2434 if (e->indirect_inlining_edge)
2435 noninlined_indir_cnt += e->count.ipa ().to_gcov_type ();
2436 else
2437 noninlined_cnt += e->count.ipa ().to_gcov_type ();
2438 }
2439 }
2440 else if (e->count.ipa ().initialized_p ())
2441 {
2442 if (e->speculative)
2443 {
2444 if (DECL_VIRTUAL_P (e->callee->decl))
2445 inlined_speculative_ply += e->count.ipa ().to_gcov_type ();
2446 else
2447 inlined_speculative += e->count.ipa ().to_gcov_type ();
2448 }
2449 else if (DECL_VIRTUAL_P (e->callee->decl))
2450 {
2451 if (e->indirect_inlining_edge)
2452 inlined_virt_indir_cnt += e->count.ipa ().to_gcov_type ();
2453 else
2454 inlined_virt_cnt += e->count.ipa ().to_gcov_type ();
2455 }
2456 else
2457 {
2458 if (e->indirect_inlining_edge)
2459 inlined_indir_cnt += e->count.ipa ().to_gcov_type ();
2460 else
2461 inlined_cnt += e->count.ipa ().to_gcov_type ();
2462 }
2463 }
2464 }
2465 for (e = node->indirect_calls; e; e = e->next_callee)
2466 if (e->indirect_info->polymorphic
2467 & e->count.ipa ().initialized_p ())
2468 indirect_poly_cnt += e->count.ipa ().to_gcov_type ();
2469 else if (e->count.ipa ().initialized_p ())
2470 indirect_cnt += e->count.ipa ().to_gcov_type ();
2471 }
2472 if (max_count.initialized_p ())
2473 {
2474 fprintf (dump_file,
2475 "Inlined %" PRId64 " + speculative "
2476 "%" PRId64 " + speculative polymorphic "
2477 "%" PRId64 " + previously indirect "
2478 "%" PRId64 " + virtual "
2479 "%" PRId64 " + virtual and previously indirect "
2480 "%" PRId64 "\n" "Not inlined "
2481 "%" PRId64 " + previously indirect "
2482 "%" PRId64 " + virtual "
2483 "%" PRId64 " + virtual and previously indirect "
2484 "%" PRId64 " + stil indirect "
2485 "%" PRId64 " + still indirect polymorphic "
2486 "%" PRId64 "\n", inlined_cnt,
2487 inlined_speculative, inlined_speculative_ply,
2488 inlined_indir_cnt, inlined_virt_cnt, inlined_virt_indir_cnt,
2489 noninlined_cnt, noninlined_indir_cnt, noninlined_virt_cnt,
2490 noninlined_virt_indir_cnt, indirect_cnt, indirect_poly_cnt);
2491 fprintf (dump_file, "Removed speculations ");
2492 spec_rem.dump (dump_file);
2493 fprintf (dump_file, "\n");
2494 }
2495 dump_overall_stats ();
2496 fprintf (dump_file, "\nWhy inlining failed?\n");
2497 for (i = 0; i < CIF_N_REASONS; i++)
2498 if (reason[i][1])
2499 fprintf (dump_file, "%-50s: %8i calls, %8f freq, %" PRId64" count\n",
2500 cgraph_inline_failed_string ((cgraph_inline_failed_t) i),
2501 (int) reason[i][1], reason_freq[i].to_double (), reason[i][0]);
2502 }
2503
2504 /* Called when node is removed. */
2505
2506 static void
2507 flatten_remove_node_hook (struct cgraph_node *node, void *data)
2508 {
2509 if (lookup_attribute ("flatten", DECL_ATTRIBUTES (node->decl)) == NULL)
2510 return;
2511
2512 hash_set<struct cgraph_node *> *removed
2513 = (hash_set<struct cgraph_node *> *) data;
2514 removed->add (node);
2515 }
2516
2517 /* Decide on the inlining. We do so in the topological order to avoid
2518 expenses on updating data structures. */
2519
2520 static unsigned int
2521 ipa_inline (void)
2522 {
2523 struct cgraph_node *node;
2524 int nnodes;
2525 struct cgraph_node **order;
2526 int i, j;
2527 int cold;
2528 bool remove_functions = false;
2529
2530 order = XCNEWVEC (struct cgraph_node *, symtab->cgraph_count);
2531
2532 if (dump_file)
2533 ipa_dump_fn_summaries (dump_file);
2534
2535 nnodes = ipa_reverse_postorder (order);
2536 spec_rem = profile_count::zero ();
2537
2538 FOR_EACH_FUNCTION (node)
2539 {
2540 node->aux = 0;
2541
2542 /* Recompute the default reasons for inlining because they may have
2543 changed during merging. */
2544 if (in_lto_p)
2545 {
2546 for (cgraph_edge *e = node->callees; e; e = e->next_callee)
2547 {
2548 gcc_assert (e->inline_failed);
2549 initialize_inline_failed (e);
2550 }
2551 for (cgraph_edge *e = node->indirect_calls; e; e = e->next_callee)
2552 initialize_inline_failed (e);
2553 }
2554 }
2555
2556 if (dump_file)
2557 fprintf (dump_file, "\nFlattening functions:\n");
2558
2559 /* First shrink order array, so that it only contains nodes with
2560 flatten attribute. */
2561 for (i = nnodes - 1, j = i; i >= 0; i--)
2562 {
2563 node = order[i];
2564 if (lookup_attribute ("flatten",
2565 DECL_ATTRIBUTES (node->decl)) != NULL)
2566 order[j--] = order[i];
2567 }
2568
2569 /* After the above loop, order[j + 1] ... order[nnodes - 1] contain
2570 nodes with flatten attribute. If there is more than one such
2571 node, we need to register a node removal hook, as flatten_function
2572 could remove other nodes with flatten attribute. See PR82801. */
2573 struct cgraph_node_hook_list *node_removal_hook_holder = NULL;
2574 hash_set<struct cgraph_node *> *flatten_removed_nodes = NULL;
2575 if (j < nnodes - 2)
2576 {
2577 flatten_removed_nodes = new hash_set<struct cgraph_node *>;
2578 node_removal_hook_holder
2579 = symtab->add_cgraph_removal_hook (&flatten_remove_node_hook,
2580 flatten_removed_nodes);
2581 }
2582
2583 /* In the first pass handle functions to be flattened. Do this with
2584 a priority so none of our later choices will make this impossible. */
2585 for (i = nnodes - 1; i > j; i--)
2586 {
2587 node = order[i];
2588 if (flatten_removed_nodes
2589 && flatten_removed_nodes->contains (node))
2590 continue;
2591
2592 /* Handle nodes to be flattened.
2593 Ideally when processing callees we stop inlining at the
2594 entry of cycles, possibly cloning that entry point and
2595 try to flatten itself turning it into a self-recursive
2596 function. */
2597 if (dump_file)
2598 fprintf (dump_file, "Flattening %s\n", node->name ());
2599 flatten_function (node, false, true);
2600 }
2601
2602 if (j < nnodes - 2)
2603 {
2604 symtab->remove_cgraph_removal_hook (node_removal_hook_holder);
2605 delete flatten_removed_nodes;
2606 }
2607 free (order);
2608
2609 if (dump_file)
2610 dump_overall_stats ();
2611
2612 inline_small_functions ();
2613
2614 gcc_assert (symtab->state == IPA_SSA);
2615 symtab->state = IPA_SSA_AFTER_INLINING;
2616 /* Do first after-inlining removal. We want to remove all "stale" extern
2617 inline functions and virtual functions so we really know what is called
2618 once. */
2619 symtab->remove_unreachable_nodes (dump_file);
2620
2621 /* Inline functions with a property that after inlining into all callers the
2622 code size will shrink because the out-of-line copy is eliminated.
2623 We do this regardless on the callee size as long as function growth limits
2624 are met. */
2625 if (dump_file)
2626 fprintf (dump_file,
2627 "\nDeciding on functions to be inlined into all callers and "
2628 "removing useless speculations:\n");
2629
2630 /* Inlining one function called once has good chance of preventing
2631 inlining other function into the same callee. Ideally we should
2632 work in priority order, but probably inlining hot functions first
2633 is good cut without the extra pain of maintaining the queue.
2634
2635 ??? this is not really fitting the bill perfectly: inlining function
2636 into callee often leads to better optimization of callee due to
2637 increased context for optimization.
2638 For example if main() function calls a function that outputs help
2639 and then function that does the main optmization, we should inline
2640 the second with priority even if both calls are cold by themselves.
2641
2642 We probably want to implement new predicate replacing our use of
2643 maybe_hot_edge interpreted as maybe_hot_edge || callee is known
2644 to be hot. */
2645 for (cold = 0; cold <= 1; cold ++)
2646 {
2647 FOR_EACH_DEFINED_FUNCTION (node)
2648 {
2649 struct cgraph_edge *edge, *next;
2650 bool update=false;
2651
2652 if (!opt_for_fn (node->decl, optimize)
2653 || !opt_for_fn (node->decl, flag_inline_functions_called_once))
2654 continue;
2655
2656 for (edge = node->callees; edge; edge = next)
2657 {
2658 next = edge->next_callee;
2659 if (edge->speculative && !speculation_useful_p (edge, false))
2660 {
2661 if (edge->count.ipa ().initialized_p ())
2662 spec_rem += edge->count.ipa ();
2663 edge->resolve_speculation ();
2664 update = true;
2665 remove_functions = true;
2666 }
2667 }
2668 if (update)
2669 {
2670 struct cgraph_node *where = node->global.inlined_to
2671 ? node->global.inlined_to : node;
2672 reset_edge_caches (where);
2673 ipa_update_overall_fn_summary (where);
2674 }
2675 if (want_inline_function_to_all_callers_p (node, cold))
2676 {
2677 int num_calls = 0;
2678 node->call_for_symbol_and_aliases (sum_callers, &num_calls,
2679 true);
2680 while (node->call_for_symbol_and_aliases
2681 (inline_to_all_callers, &num_calls, true))
2682 ;
2683 remove_functions = true;
2684 }
2685 }
2686 }
2687
2688 /* Free ipa-prop structures if they are no longer needed. */
2689 ipa_free_all_structures_after_iinln ();
2690
2691 if (dump_enabled_p ())
2692 dump_printf (MSG_NOTE,
2693 "\nInlined %i calls, eliminated %i functions\n\n",
2694 ncalls_inlined, nfunctions_inlined);
2695 if (dump_file)
2696 dump_inline_stats ();
2697
2698 if (dump_file)
2699 ipa_dump_fn_summaries (dump_file);
2700 return remove_functions ? TODO_remove_functions : 0;
2701 }
2702
2703 /* Inline always-inline function calls in NODE. */
2704
2705 static bool
2706 inline_always_inline_functions (struct cgraph_node *node)
2707 {
2708 struct cgraph_edge *e;
2709 bool inlined = false;
2710
2711 for (e = node->callees; e; e = e->next_callee)
2712 {
2713 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
2714 if (!DECL_DISREGARD_INLINE_LIMITS (callee->decl))
2715 continue;
2716
2717 if (e->recursive_p ())
2718 {
2719 if (dump_enabled_p ())
2720 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
2721 " Not inlining recursive call to %C.\n",
2722 e->callee);
2723 e->inline_failed = CIF_RECURSIVE_INLINING;
2724 continue;
2725 }
2726
2727 if (!can_early_inline_edge_p (e))
2728 {
2729 /* Set inlined to true if the callee is marked "always_inline" but
2730 is not inlinable. This will allow flagging an error later in
2731 expand_call_inline in tree-inline.c. */
2732 if (lookup_attribute ("always_inline",
2733 DECL_ATTRIBUTES (callee->decl)) != NULL)
2734 inlined = true;
2735 continue;
2736 }
2737
2738 if (dump_enabled_p ())
2739 dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, e->call_stmt,
2740 " Inlining %C into %C (always_inline).\n",
2741 e->callee, e->caller);
2742 inline_call (e, true, NULL, NULL, false);
2743 inlined = true;
2744 }
2745 if (inlined)
2746 ipa_update_overall_fn_summary (node);
2747
2748 return inlined;
2749 }
2750
2751 /* Decide on the inlining. We do so in the topological order to avoid
2752 expenses on updating data structures. */
2753
2754 static bool
2755 early_inline_small_functions (struct cgraph_node *node)
2756 {
2757 struct cgraph_edge *e;
2758 bool inlined = false;
2759
2760 for (e = node->callees; e; e = e->next_callee)
2761 {
2762 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
2763
2764 /* We can enounter not-yet-analyzed function during
2765 early inlining on callgraphs with strongly
2766 connected components. */
2767 ipa_fn_summary *s = ipa_fn_summaries->get (callee);
2768 if (s == NULL || !s->inlinable || !e->inline_failed)
2769 continue;
2770
2771 /* Do not consider functions not declared inline. */
2772 if (!DECL_DECLARED_INLINE_P (callee->decl)
2773 && !opt_for_fn (node->decl, flag_inline_small_functions)
2774 && !opt_for_fn (node->decl, flag_inline_functions))
2775 continue;
2776
2777 if (dump_enabled_p ())
2778 dump_printf_loc (MSG_NOTE, e->call_stmt,
2779 "Considering inline candidate %C.\n",
2780 callee);
2781
2782 if (!can_early_inline_edge_p (e))
2783 continue;
2784
2785 if (e->recursive_p ())
2786 {
2787 if (dump_enabled_p ())
2788 dump_printf_loc (MSG_MISSED_OPTIMIZATION, e->call_stmt,
2789 " Not inlining: recursive call.\n");
2790 continue;
2791 }
2792
2793 if (!want_early_inline_function_p (e))
2794 continue;
2795
2796 if (dump_enabled_p ())
2797 dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, e->call_stmt,
2798 " Inlining %C into %C.\n",
2799 callee, e->caller);
2800 inline_call (e, true, NULL, NULL, false);
2801 inlined = true;
2802 }
2803
2804 if (inlined)
2805 ipa_update_overall_fn_summary (node);
2806
2807 return inlined;
2808 }
2809
2810 unsigned int
2811 early_inliner (function *fun)
2812 {
2813 struct cgraph_node *node = cgraph_node::get (current_function_decl);
2814 struct cgraph_edge *edge;
2815 unsigned int todo = 0;
2816 int iterations = 0;
2817 bool inlined = false;
2818
2819 if (seen_error ())
2820 return 0;
2821
2822 /* Do nothing if datastructures for ipa-inliner are already computed. This
2823 happens when some pass decides to construct new function and
2824 cgraph_add_new_function calls lowering passes and early optimization on
2825 it. This may confuse ourself when early inliner decide to inline call to
2826 function clone, because function clones don't have parameter list in
2827 ipa-prop matching their signature. */
2828 if (ipa_node_params_sum)
2829 return 0;
2830
2831 if (flag_checking)
2832 node->verify ();
2833 node->remove_all_references ();
2834
2835 /* Even when not optimizing or not inlining inline always-inline
2836 functions. */
2837 inlined = inline_always_inline_functions (node);
2838
2839 if (!optimize
2840 || flag_no_inline
2841 || !flag_early_inlining
2842 /* Never inline regular functions into always-inline functions
2843 during incremental inlining. This sucks as functions calling
2844 always inline functions will get less optimized, but at the
2845 same time inlining of functions calling always inline
2846 function into an always inline function might introduce
2847 cycles of edges to be always inlined in the callgraph.
2848
2849 We might want to be smarter and just avoid this type of inlining. */
2850 || (DECL_DISREGARD_INLINE_LIMITS (node->decl)
2851 && lookup_attribute ("always_inline",
2852 DECL_ATTRIBUTES (node->decl))))
2853 ;
2854 else if (lookup_attribute ("flatten",
2855 DECL_ATTRIBUTES (node->decl)) != NULL)
2856 {
2857 /* When the function is marked to be flattened, recursively inline
2858 all calls in it. */
2859 if (dump_enabled_p ())
2860 dump_printf (MSG_OPTIMIZED_LOCATIONS,
2861 "Flattening %C\n", node);
2862 flatten_function (node, true, true);
2863 inlined = true;
2864 }
2865 else
2866 {
2867 /* If some always_inline functions was inlined, apply the changes.
2868 This way we will not account always inline into growth limits and
2869 moreover we will inline calls from always inlines that we skipped
2870 previously because of conditional above. */
2871 if (inlined)
2872 {
2873 timevar_push (TV_INTEGRATION);
2874 todo |= optimize_inline_calls (current_function_decl);
2875 /* optimize_inline_calls call above might have introduced new
2876 statements that don't have inline parameters computed. */
2877 for (edge = node->callees; edge; edge = edge->next_callee)
2878 {
2879 /* We can enounter not-yet-analyzed function during
2880 early inlining on callgraphs with strongly
2881 connected components. */
2882 ipa_call_summary *es = ipa_call_summaries->get_create (edge);
2883 es->call_stmt_size
2884 = estimate_num_insns (edge->call_stmt, &eni_size_weights);
2885 es->call_stmt_time
2886 = estimate_num_insns (edge->call_stmt, &eni_time_weights);
2887 }
2888 ipa_update_overall_fn_summary (node);
2889 inlined = false;
2890 timevar_pop (TV_INTEGRATION);
2891 }
2892 /* We iterate incremental inlining to get trivial cases of indirect
2893 inlining. */
2894 while (iterations < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS)
2895 && early_inline_small_functions (node))
2896 {
2897 timevar_push (TV_INTEGRATION);
2898 todo |= optimize_inline_calls (current_function_decl);
2899
2900 /* Technically we ought to recompute inline parameters so the new
2901 iteration of early inliner works as expected. We however have
2902 values approximately right and thus we only need to update edge
2903 info that might be cleared out for newly discovered edges. */
2904 for (edge = node->callees; edge; edge = edge->next_callee)
2905 {
2906 /* We have no summary for new bound store calls yet. */
2907 ipa_call_summary *es = ipa_call_summaries->get_create (edge);
2908 es->call_stmt_size
2909 = estimate_num_insns (edge->call_stmt, &eni_size_weights);
2910 es->call_stmt_time
2911 = estimate_num_insns (edge->call_stmt, &eni_time_weights);
2912
2913 if (edge->callee->decl
2914 && !gimple_check_call_matching_types (
2915 edge->call_stmt, edge->callee->decl, false))
2916 {
2917 edge->inline_failed = CIF_MISMATCHED_ARGUMENTS;
2918 edge->call_stmt_cannot_inline_p = true;
2919 }
2920 }
2921 if (iterations < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS) - 1)
2922 ipa_update_overall_fn_summary (node);
2923 timevar_pop (TV_INTEGRATION);
2924 iterations++;
2925 inlined = false;
2926 }
2927 if (dump_file)
2928 fprintf (dump_file, "Iterations: %i\n", iterations);
2929 }
2930
2931 if (inlined)
2932 {
2933 timevar_push (TV_INTEGRATION);
2934 todo |= optimize_inline_calls (current_function_decl);
2935 timevar_pop (TV_INTEGRATION);
2936 }
2937
2938 fun->always_inline_functions_inlined = true;
2939
2940 return todo;
2941 }
2942
2943 /* Do inlining of small functions. Doing so early helps profiling and other
2944 passes to be somewhat more effective and avoids some code duplication in
2945 later real inlining pass for testcases with very many function calls. */
2946
2947 namespace {
2948
2949 const pass_data pass_data_early_inline =
2950 {
2951 GIMPLE_PASS, /* type */
2952 "einline", /* name */
2953 OPTGROUP_INLINE, /* optinfo_flags */
2954 TV_EARLY_INLINING, /* tv_id */
2955 PROP_ssa, /* properties_required */
2956 0, /* properties_provided */
2957 0, /* properties_destroyed */
2958 0, /* todo_flags_start */
2959 0, /* todo_flags_finish */
2960 };
2961
2962 class pass_early_inline : public gimple_opt_pass
2963 {
2964 public:
2965 pass_early_inline (gcc::context *ctxt)
2966 : gimple_opt_pass (pass_data_early_inline, ctxt)
2967 {}
2968
2969 /* opt_pass methods: */
2970 virtual unsigned int execute (function *);
2971
2972 }; // class pass_early_inline
2973
2974 unsigned int
2975 pass_early_inline::execute (function *fun)
2976 {
2977 return early_inliner (fun);
2978 }
2979
2980 } // anon namespace
2981
2982 gimple_opt_pass *
2983 make_pass_early_inline (gcc::context *ctxt)
2984 {
2985 return new pass_early_inline (ctxt);
2986 }
2987
2988 namespace {
2989
2990 const pass_data pass_data_ipa_inline =
2991 {
2992 IPA_PASS, /* type */
2993 "inline", /* name */
2994 OPTGROUP_INLINE, /* optinfo_flags */
2995 TV_IPA_INLINING, /* tv_id */
2996 0, /* properties_required */
2997 0, /* properties_provided */
2998 0, /* properties_destroyed */
2999 0, /* todo_flags_start */
3000 ( TODO_dump_symtab ), /* todo_flags_finish */
3001 };
3002
3003 class pass_ipa_inline : public ipa_opt_pass_d
3004 {
3005 public:
3006 pass_ipa_inline (gcc::context *ctxt)
3007 : ipa_opt_pass_d (pass_data_ipa_inline, ctxt,
3008 NULL, /* generate_summary */
3009 NULL, /* write_summary */
3010 NULL, /* read_summary */
3011 NULL, /* write_optimization_summary */
3012 NULL, /* read_optimization_summary */
3013 NULL, /* stmt_fixup */
3014 0, /* function_transform_todo_flags_start */
3015 inline_transform, /* function_transform */
3016 NULL) /* variable_transform */
3017 {}
3018
3019 /* opt_pass methods: */
3020 virtual unsigned int execute (function *) { return ipa_inline (); }
3021
3022 }; // class pass_ipa_inline
3023
3024 } // anon namespace
3025
3026 ipa_opt_pass_d *
3027 make_pass_ipa_inline (gcc::context *ctxt)
3028 {
3029 return new pass_ipa_inline (ctxt);
3030 }