* lto-symtab.c (warn_type_compatibility_p): Do not set ODR mismatch
[official-gcc.git] / gcc / ipa-inline.c
blob01bfe0effda6eb6f3e36e8253378bf4f025a7fa2
1 /* Inlining decision heuristics.
2 Copyright (C) 2003-2015 Free Software Foundation, Inc.
3 Contributed by Jan Hubicka
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* Inlining decision heuristics
23 The implementation of inliner is organized as follows:
25 inlining heuristics limits
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).
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.
36 inlining heuristics
38 The inliner itself is split into two passes:
40 pass_early_inlining
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.
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.
53 The pass handle the obvious inlining decisions within the compilation
54 unit - inlining auto inline functions, inlining for size and
55 flattening.
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.
62 Because of lack of whole unit knowledge, the pass can not 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.
68 pass_ipa_inline
70 This is the real inliner able to handle inlining with whole program
71 knowledge. It performs following steps:
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.
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.
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.
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. */
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 "ipa-prop.h"
112 #include "ipa-inline.h"
113 #include "ipa-utils.h"
114 #include "sreal.h"
115 #include "auto-profile.h"
116 #include "builtins.h"
117 #include "fibonacci_heap.h"
119 typedef fibonacci_heap <sreal, cgraph_edge> edge_heap_t;
120 typedef fibonacci_node <sreal, cgraph_edge> edge_heap_node_t;
122 /* Statistics we collect about inlining algorithm. */
123 static int overall_size;
124 static gcov_type max_count;
125 static gcov_type spec_rem;
127 /* Pre-computed constants 1/CGRAPH_FREQ_BASE and 1/100. */
128 static sreal cgraph_freq_base_rec, percent_rec;
130 /* Return false when inlining edge E would lead to violating
131 limits on function unit growth or stack usage growth.
133 The relative function body growth limit is present generally
134 to avoid problems with non-linear behavior of the compiler.
135 To allow inlining huge functions into tiny wrapper, the limit
136 is always based on the bigger of the two functions considered.
138 For stack growth limits we always base the growth in stack usage
139 of the callers. We want to prevent applications from segfaulting
140 on stack overflow when functions with huge stack frames gets
141 inlined. */
143 static bool
144 caller_growth_limits (struct cgraph_edge *e)
146 struct cgraph_node *to = e->caller;
147 struct cgraph_node *what = e->callee->ultimate_alias_target ();
148 int newsize;
149 int limit = 0;
150 HOST_WIDE_INT stack_size_limit = 0, inlined_stack;
151 inline_summary *info, *what_info, *outer_info = inline_summaries->get (to);
153 /* Look for function e->caller is inlined to. While doing
154 so work out the largest function body on the way. As
155 described above, we want to base our function growth
156 limits based on that. Not on the self size of the
157 outer function, not on the self size of inline code
158 we immediately inline to. This is the most relaxed
159 interpretation of the rule "do not grow large functions
160 too much in order to prevent compiler from exploding". */
161 while (true)
163 info = inline_summaries->get (to);
164 if (limit < info->self_size)
165 limit = info->self_size;
166 if (stack_size_limit < info->estimated_self_stack_size)
167 stack_size_limit = info->estimated_self_stack_size;
168 if (to->global.inlined_to)
169 to = to->callers->caller;
170 else
171 break;
174 what_info = inline_summaries->get (what);
176 if (limit < what_info->self_size)
177 limit = what_info->self_size;
179 limit += limit * PARAM_VALUE (PARAM_LARGE_FUNCTION_GROWTH) / 100;
181 /* Check the size after inlining against the function limits. But allow
182 the function to shrink if it went over the limits by forced inlining. */
183 newsize = estimate_size_after_inlining (to, e);
184 if (newsize >= info->size
185 && newsize > PARAM_VALUE (PARAM_LARGE_FUNCTION_INSNS)
186 && newsize > limit)
188 e->inline_failed = CIF_LARGE_FUNCTION_GROWTH_LIMIT;
189 return false;
192 if (!what_info->estimated_stack_size)
193 return true;
195 /* FIXME: Stack size limit often prevents inlining in Fortran programs
196 due to large i/o datastructures used by the Fortran front-end.
197 We ought to ignore this limit when we know that the edge is executed
198 on every invocation of the caller (i.e. its call statement dominates
199 exit block). We do not track this information, yet. */
200 stack_size_limit += ((gcov_type)stack_size_limit
201 * PARAM_VALUE (PARAM_STACK_FRAME_GROWTH) / 100);
203 inlined_stack = (outer_info->stack_frame_offset
204 + outer_info->estimated_self_stack_size
205 + what_info->estimated_stack_size);
206 /* Check new stack consumption with stack consumption at the place
207 stack is used. */
208 if (inlined_stack > stack_size_limit
209 /* If function already has large stack usage from sibling
210 inline call, we can inline, too.
211 This bit overoptimistically assume that we are good at stack
212 packing. */
213 && inlined_stack > info->estimated_stack_size
214 && inlined_stack > PARAM_VALUE (PARAM_LARGE_STACK_FRAME))
216 e->inline_failed = CIF_LARGE_STACK_FRAME_GROWTH_LIMIT;
217 return false;
219 return true;
222 /* Dump info about why inlining has failed. */
224 static void
225 report_inline_failed_reason (struct cgraph_edge *e)
227 if (dump_file)
229 fprintf (dump_file, " not inlinable: %s/%i -> %s/%i, %s\n",
230 xstrdup_for_dump (e->caller->name ()), e->caller->order,
231 xstrdup_for_dump (e->callee->name ()), e->callee->order,
232 cgraph_inline_failed_string (e->inline_failed));
233 if ((e->inline_failed == CIF_TARGET_OPTION_MISMATCH
234 || e->inline_failed == CIF_OPTIMIZATION_MISMATCH)
235 && e->caller->lto_file_data
236 && e->callee->function_symbol ()->lto_file_data)
238 fprintf (dump_file, " LTO objects: %s, %s\n",
239 e->caller->lto_file_data->file_name,
240 e->callee->function_symbol ()->lto_file_data->file_name);
242 if (e->inline_failed == CIF_TARGET_OPTION_MISMATCH)
243 cl_target_option_print_diff
244 (dump_file, 2, target_opts_for_fn (e->caller->decl),
245 target_opts_for_fn (e->callee->ultimate_alias_target ()->decl));
246 if (e->inline_failed == CIF_OPTIMIZATION_MISMATCH)
247 cl_optimization_print_diff
248 (dump_file, 2, opts_for_fn (e->caller->decl),
249 opts_for_fn (e->callee->ultimate_alias_target ()->decl));
253 /* Decide whether sanitizer-related attributes allow inlining. */
255 static bool
256 sanitize_attrs_match_for_inline_p (const_tree caller, const_tree callee)
258 /* Don't care if sanitizer is disabled */
259 if (!(flag_sanitize & SANITIZE_ADDRESS))
260 return true;
262 if (!caller || !callee)
263 return true;
265 return !!lookup_attribute ("no_sanitize_address",
266 DECL_ATTRIBUTES (caller)) ==
267 !!lookup_attribute ("no_sanitize_address",
268 DECL_ATTRIBUTES (callee));
271 /* Used for flags where it is safe to inline when caller's value is
272 grater than callee's. */
273 #define check_maybe_up(flag) \
274 (opts_for_fn (caller->decl)->x_##flag \
275 != opts_for_fn (callee->decl)->x_##flag \
276 && (!always_inline \
277 || opts_for_fn (caller->decl)->x_##flag \
278 < opts_for_fn (callee->decl)->x_##flag))
279 /* Used for flags where it is safe to inline when caller's value is
280 smaller than callee's. */
281 #define check_maybe_down(flag) \
282 (opts_for_fn (caller->decl)->x_##flag \
283 != opts_for_fn (callee->decl)->x_##flag \
284 && (!always_inline \
285 || opts_for_fn (caller->decl)->x_##flag \
286 > opts_for_fn (callee->decl)->x_##flag))
287 /* Used for flags where exact match is needed for correctness. */
288 #define check_match(flag) \
289 (opts_for_fn (caller->decl)->x_##flag \
290 != opts_for_fn (callee->decl)->x_##flag)
292 /* Decide if we can inline the edge and possibly update
293 inline_failed reason.
294 We check whether inlining is possible at all and whether
295 caller growth limits allow doing so.
297 if REPORT is true, output reason to the dump file.
299 if DISREGARD_LIMITS is true, ignore size limits.*/
301 static bool
302 can_inline_edge_p (struct cgraph_edge *e, bool report,
303 bool disregard_limits = false, bool early = false)
305 gcc_checking_assert (e->inline_failed);
307 if (cgraph_inline_failed_type (e->inline_failed) == CIF_FINAL_ERROR)
309 if (report)
310 report_inline_failed_reason (e);
311 return false;
314 bool inlinable = true;
315 enum availability avail;
316 cgraph_node *callee = e->callee->ultimate_alias_target (&avail);
317 cgraph_node *caller = e->caller->global.inlined_to
318 ? e->caller->global.inlined_to : e->caller;
319 tree caller_tree = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (caller->decl);
320 tree callee_tree
321 = callee ? DECL_FUNCTION_SPECIFIC_OPTIMIZATION (callee->decl) : NULL;
323 if (!callee->definition)
325 e->inline_failed = CIF_BODY_NOT_AVAILABLE;
326 inlinable = false;
328 else if (callee->calls_comdat_local)
330 e->inline_failed = CIF_USES_COMDAT_LOCAL;
331 inlinable = false;
333 else if (avail <= AVAIL_INTERPOSABLE)
335 e->inline_failed = CIF_OVERWRITABLE;
336 inlinable = false;
338 else if (e->call_stmt_cannot_inline_p)
340 if (e->inline_failed != CIF_FUNCTION_NOT_OPTIMIZED)
341 e->inline_failed = CIF_MISMATCHED_ARGUMENTS;
342 inlinable = false;
344 /* Don't inline if the functions have different EH personalities. */
345 else if (DECL_FUNCTION_PERSONALITY (caller->decl)
346 && DECL_FUNCTION_PERSONALITY (callee->decl)
347 && (DECL_FUNCTION_PERSONALITY (caller->decl)
348 != DECL_FUNCTION_PERSONALITY (callee->decl)))
350 e->inline_failed = CIF_EH_PERSONALITY;
351 inlinable = false;
353 /* TM pure functions should not be inlined into non-TM_pure
354 functions. */
355 else if (is_tm_pure (callee->decl) && !is_tm_pure (caller->decl))
357 e->inline_failed = CIF_UNSPECIFIED;
358 inlinable = false;
360 /* Check compatibility of target optimization options. */
361 else if (!targetm.target_option.can_inline_p (caller->decl,
362 callee->decl))
364 e->inline_failed = CIF_TARGET_OPTION_MISMATCH;
365 inlinable = false;
367 else if (!inline_summaries->get (callee)->inlinable)
369 e->inline_failed = CIF_FUNCTION_NOT_INLINABLE;
370 inlinable = false;
372 else if (inline_summaries->get (caller)->contains_cilk_spawn)
374 e->inline_failed = CIF_CILK_SPAWN;
375 inlinable = false;
377 /* Don't inline a function with mismatched sanitization attributes. */
378 else if (!sanitize_attrs_match_for_inline_p (caller->decl, callee->decl))
380 e->inline_failed = CIF_ATTRIBUTE_MISMATCH;
381 inlinable = false;
383 /* Check if caller growth allows the inlining. */
384 else if (!DECL_DISREGARD_INLINE_LIMITS (callee->decl)
385 && !disregard_limits
386 && !lookup_attribute ("flatten",
387 DECL_ATTRIBUTES (caller->decl))
388 && !caller_growth_limits (e))
389 inlinable = false;
390 /* Don't inline a function with a higher optimization level than the
391 caller. FIXME: this is really just tip of iceberg of handling
392 optimization attribute. */
393 else if (caller_tree != callee_tree)
395 bool always_inline =
396 (DECL_DISREGARD_INLINE_LIMITS (callee->decl)
397 && lookup_attribute ("always_inline",
398 DECL_ATTRIBUTES (callee->decl)));
400 /* Until GCC 4.9 we did not check the semantics alterning flags
401 bellow and inline across optimization boundry.
402 Enabling checks bellow breaks several packages by refusing
403 to inline library always_inline functions. See PR65873.
404 Disable the check for early inlining for now until better solution
405 is found. */
406 if (always_inline && early)
408 /* There are some options that change IL semantics which means
409 we cannot inline in these cases for correctness reason.
410 Not even for always_inline declared functions. */
411 /* Strictly speaking only when the callee contains signed integer
412 math where overflow is undefined. */
413 else if ((check_maybe_up (flag_strict_overflow)
414 /* this flag is set by optimize. Allow inlining across
415 optimize boundary. */
416 && (!opt_for_fn (caller->decl, optimize)
417 == !opt_for_fn (callee->decl, optimize) || !always_inline))
418 || check_match (flag_wrapv)
419 || check_match (flag_trapv)
420 /* Strictly speaking only when the callee uses FP math. */
421 || check_maybe_up (flag_rounding_math)
422 || check_maybe_up (flag_trapping_math)
423 || check_maybe_down (flag_unsafe_math_optimizations)
424 || check_maybe_down (flag_finite_math_only)
425 || check_maybe_up (flag_signaling_nans)
426 || check_maybe_down (flag_cx_limited_range)
427 || check_maybe_up (flag_signed_zeros)
428 || check_maybe_down (flag_associative_math)
429 || check_maybe_down (flag_reciprocal_math)
430 /* We do not want to make code compiled with exceptions to be
431 brought into a non-EH function unless we know that the callee
432 does not throw.
433 This is tracked by DECL_FUNCTION_PERSONALITY. */
434 || (check_match (flag_non_call_exceptions)
435 /* TODO: We also may allow bringing !flag_non_call_exceptions
436 to flag_non_call_exceptions function, but that may need
437 extra work in tree-inline to add the extra EH edges. */
438 && (!opt_for_fn (callee->decl, flag_non_call_exceptions)
439 || DECL_FUNCTION_PERSONALITY (callee->decl)))
440 || (check_maybe_up (flag_exceptions)
441 && DECL_FUNCTION_PERSONALITY (callee->decl))
442 /* Strictly speaking only when the callee contains function
443 calls that may end up setting errno. */
444 || check_maybe_up (flag_errno_math)
445 /* When devirtualization is diabled for callee, it is not safe
446 to inline it as we possibly mangled the type info.
447 Allow early inlining of always inlines. */
448 || (!early && check_maybe_down (flag_devirtualize)))
450 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
451 inlinable = false;
453 /* gcc.dg/pr43564.c. Apply user-forced inline even at -O0. */
454 else if (always_inline)
456 /* When user added an attribute to the callee honor it. */
457 else if (lookup_attribute ("optimize", DECL_ATTRIBUTES (callee->decl))
458 && opts_for_fn (caller->decl) != opts_for_fn (callee->decl))
460 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
461 inlinable = false;
463 /* If explicit optimize attribute are not used, the mismatch is caused
464 by different command line options used to build different units.
465 Do not care about COMDAT functions - those are intended to be
466 optimized with the optimization flags of module they are used in.
467 Also do not care about mixing up size/speed optimization when
468 DECL_DISREGARD_INLINE_LIMITS is set. */
469 else if ((callee->merged
470 && !lookup_attribute ("optimize",
471 DECL_ATTRIBUTES (caller->decl)))
472 || DECL_DISREGARD_INLINE_LIMITS (callee->decl))
474 /* If mismatch is caused by merging two LTO units with different
475 optimizationflags we want to be bit nicer. However never inline
476 if one of functions is not optimized at all. */
477 else if (!opt_for_fn (callee->decl, optimize)
478 || !opt_for_fn (caller->decl, optimize))
480 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
481 inlinable = false;
483 /* If callee is optimized for size and caller is not, allow inlining if
484 code shrinks or we are in MAX_INLINE_INSNS_SINGLE limit and callee
485 is inline (and thus likely an unified comdat). This will allow caller
486 to run faster. */
487 else if (opt_for_fn (callee->decl, optimize_size)
488 > opt_for_fn (caller->decl, optimize_size))
490 int growth = estimate_edge_growth (e);
491 if (growth > 0
492 && (!DECL_DECLARED_INLINE_P (callee->decl)
493 && growth >= MAX (MAX_INLINE_INSNS_SINGLE,
494 MAX_INLINE_INSNS_AUTO)))
496 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
497 inlinable = false;
500 /* If callee is more aggressively optimized for performance than caller,
501 we generally want to inline only cheap (runtime wise) functions. */
502 else if (opt_for_fn (callee->decl, optimize_size)
503 < opt_for_fn (caller->decl, optimize_size)
504 || (opt_for_fn (callee->decl, optimize)
505 > opt_for_fn (caller->decl, optimize)))
507 if (estimate_edge_time (e)
508 >= 20 + inline_edge_summary (e)->call_stmt_time)
510 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
511 inlinable = false;
517 if (!inlinable && report)
518 report_inline_failed_reason (e);
519 return inlinable;
523 /* Return true if the edge E is inlinable during early inlining. */
525 static bool
526 can_early_inline_edge_p (struct cgraph_edge *e)
528 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
529 /* Early inliner might get called at WPA stage when IPA pass adds new
530 function. In this case we can not really do any of early inlining
531 because function bodies are missing. */
532 if (!gimple_has_body_p (callee->decl))
534 e->inline_failed = CIF_BODY_NOT_AVAILABLE;
535 return false;
537 /* In early inliner some of callees may not be in SSA form yet
538 (i.e. the callgraph is cyclic and we did not process
539 the callee by early inliner, yet). We don't have CIF code for this
540 case; later we will re-do the decision in the real inliner. */
541 if (!gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->caller->decl))
542 || !gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->decl)))
544 if (dump_file)
545 fprintf (dump_file, " edge not inlinable: not in SSA form\n");
546 return false;
548 if (!can_inline_edge_p (e, true, false, true))
549 return false;
550 return true;
554 /* Return number of calls in N. Ignore cheap builtins. */
556 static int
557 num_calls (struct cgraph_node *n)
559 struct cgraph_edge *e;
560 int num = 0;
562 for (e = n->callees; e; e = e->next_callee)
563 if (!is_inexpensive_builtin (e->callee->decl))
564 num++;
565 return num;
569 /* Return true if we are interested in inlining small function. */
571 static bool
572 want_early_inline_function_p (struct cgraph_edge *e)
574 bool want_inline = true;
575 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
577 if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
579 /* For AutoFDO, we need to make sure that before profile summary, all
580 hot paths' IR look exactly the same as profiled binary. As a result,
581 in einliner, we will disregard size limit and inline those callsites
582 that are:
583 * inlined in the profiled binary, and
584 * the cloned callee has enough samples to be considered "hot". */
585 else if (flag_auto_profile && afdo_callsite_hot_enough_for_early_inline (e))
587 else if (!DECL_DECLARED_INLINE_P (callee->decl)
588 && !opt_for_fn (e->caller->decl, flag_inline_small_functions))
590 e->inline_failed = CIF_FUNCTION_NOT_INLINE_CANDIDATE;
591 report_inline_failed_reason (e);
592 want_inline = false;
594 else
596 int growth = estimate_edge_growth (e);
597 int n;
599 if (growth <= 0)
601 else if (!e->maybe_hot_p ()
602 && growth > 0)
604 if (dump_file)
605 fprintf (dump_file, " will not early inline: %s/%i->%s/%i, "
606 "call is cold and code would grow by %i\n",
607 xstrdup_for_dump (e->caller->name ()),
608 e->caller->order,
609 xstrdup_for_dump (callee->name ()), callee->order,
610 growth);
611 want_inline = false;
613 else if (growth > PARAM_VALUE (PARAM_EARLY_INLINING_INSNS))
615 if (dump_file)
616 fprintf (dump_file, " will not early inline: %s/%i->%s/%i, "
617 "growth %i exceeds --param early-inlining-insns\n",
618 xstrdup_for_dump (e->caller->name ()),
619 e->caller->order,
620 xstrdup_for_dump (callee->name ()), callee->order,
621 growth);
622 want_inline = false;
624 else if ((n = num_calls (callee)) != 0
625 && growth * (n + 1) > PARAM_VALUE (PARAM_EARLY_INLINING_INSNS))
627 if (dump_file)
628 fprintf (dump_file, " will not early inline: %s/%i->%s/%i, "
629 "growth %i exceeds --param early-inlining-insns "
630 "divided by number of calls\n",
631 xstrdup_for_dump (e->caller->name ()),
632 e->caller->order,
633 xstrdup_for_dump (callee->name ()), callee->order,
634 growth);
635 want_inline = false;
638 return want_inline;
641 /* Compute time of the edge->caller + edge->callee execution when inlining
642 does not happen. */
644 inline sreal
645 compute_uninlined_call_time (struct inline_summary *callee_info,
646 struct cgraph_edge *edge)
648 sreal uninlined_call_time = (sreal)callee_info->time;
649 cgraph_node *caller = (edge->caller->global.inlined_to
650 ? edge->caller->global.inlined_to
651 : edge->caller);
653 if (edge->count && caller->count)
654 uninlined_call_time *= (sreal)edge->count / caller->count;
655 if (edge->frequency)
656 uninlined_call_time *= cgraph_freq_base_rec * edge->frequency;
657 else
658 uninlined_call_time = uninlined_call_time >> 11;
660 int caller_time = inline_summaries->get (caller)->time;
661 return uninlined_call_time + caller_time;
664 /* Same as compute_uinlined_call_time but compute time when inlining
665 does happen. */
667 inline sreal
668 compute_inlined_call_time (struct cgraph_edge *edge,
669 int edge_time)
671 cgraph_node *caller = (edge->caller->global.inlined_to
672 ? edge->caller->global.inlined_to
673 : edge->caller);
674 int caller_time = inline_summaries->get (caller)->time;
675 sreal time = edge_time;
677 if (edge->count && caller->count)
678 time *= (sreal)edge->count / caller->count;
679 if (edge->frequency)
680 time *= cgraph_freq_base_rec * edge->frequency;
681 else
682 time = time >> 11;
684 /* This calculation should match one in ipa-inline-analysis.
685 FIXME: Once ipa-inline-analysis is converted to sreal this can be
686 simplified. */
687 time -= (sreal) ((gcov_type) edge->frequency
688 * inline_edge_summary (edge)->call_stmt_time
689 * (INLINE_TIME_SCALE / CGRAPH_FREQ_BASE)) / INLINE_TIME_SCALE;
690 time += caller_time;
691 if (time <= 0)
692 time = ((sreal) 1) >> 8;
693 gcc_checking_assert (time >= 0);
694 return time;
697 /* Return true if the speedup for inlining E is bigger than
698 PARAM_MAX_INLINE_MIN_SPEEDUP. */
700 static bool
701 big_speedup_p (struct cgraph_edge *e)
703 sreal time = compute_uninlined_call_time (inline_summaries->get (e->callee),
705 sreal inlined_time = compute_inlined_call_time (e, estimate_edge_time (e));
707 if (time - inlined_time
708 > (sreal) time * PARAM_VALUE (PARAM_INLINE_MIN_SPEEDUP)
709 * percent_rec)
710 return true;
711 return false;
714 /* Return true if we are interested in inlining small function.
715 When REPORT is true, report reason to dump file. */
717 static bool
718 want_inline_small_function_p (struct cgraph_edge *e, bool report)
720 bool want_inline = true;
721 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
723 if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
725 else if (!DECL_DECLARED_INLINE_P (callee->decl)
726 && !opt_for_fn (e->caller->decl, flag_inline_small_functions))
728 e->inline_failed = CIF_FUNCTION_NOT_INLINE_CANDIDATE;
729 want_inline = false;
731 /* Do fast and conservative check if the function can be good
732 inline candidate. At the moment we allow inline hints to
733 promote non-inline functions to inline and we increase
734 MAX_INLINE_INSNS_SINGLE 16-fold for inline functions. */
735 else if ((!DECL_DECLARED_INLINE_P (callee->decl)
736 && (!e->count || !e->maybe_hot_p ()))
737 && inline_summaries->get (callee)->min_size
738 - inline_edge_summary (e)->call_stmt_size
739 > MAX (MAX_INLINE_INSNS_SINGLE, MAX_INLINE_INSNS_AUTO))
741 e->inline_failed = CIF_MAX_INLINE_INSNS_AUTO_LIMIT;
742 want_inline = false;
744 else if ((DECL_DECLARED_INLINE_P (callee->decl) || e->count)
745 && inline_summaries->get (callee)->min_size
746 - inline_edge_summary (e)->call_stmt_size
747 > 16 * MAX_INLINE_INSNS_SINGLE)
749 e->inline_failed = (DECL_DECLARED_INLINE_P (callee->decl)
750 ? CIF_MAX_INLINE_INSNS_SINGLE_LIMIT
751 : CIF_MAX_INLINE_INSNS_AUTO_LIMIT);
752 want_inline = false;
754 else
756 int growth = estimate_edge_growth (e);
757 inline_hints hints = estimate_edge_hints (e);
758 bool big_speedup = big_speedup_p (e);
760 if (growth <= 0)
762 /* Apply MAX_INLINE_INSNS_SINGLE limit. Do not do so when
763 hints suggests that inlining given function is very profitable. */
764 else if (DECL_DECLARED_INLINE_P (callee->decl)
765 && growth >= MAX_INLINE_INSNS_SINGLE
766 && ((!big_speedup
767 && !(hints & (INLINE_HINT_indirect_call
768 | INLINE_HINT_known_hot
769 | INLINE_HINT_loop_iterations
770 | INLINE_HINT_array_index
771 | INLINE_HINT_loop_stride)))
772 || growth >= MAX_INLINE_INSNS_SINGLE * 16))
774 e->inline_failed = CIF_MAX_INLINE_INSNS_SINGLE_LIMIT;
775 want_inline = false;
777 else if (!DECL_DECLARED_INLINE_P (callee->decl)
778 && !opt_for_fn (e->caller->decl, flag_inline_functions))
780 /* growth_likely_positive is expensive, always test it last. */
781 if (growth >= MAX_INLINE_INSNS_SINGLE
782 || growth_likely_positive (callee, growth))
784 e->inline_failed = CIF_NOT_DECLARED_INLINED;
785 want_inline = false;
788 /* Apply MAX_INLINE_INSNS_AUTO limit for functions not declared inline
789 Upgrade it to MAX_INLINE_INSNS_SINGLE when hints suggests that
790 inlining given function is very profitable. */
791 else if (!DECL_DECLARED_INLINE_P (callee->decl)
792 && !big_speedup
793 && !(hints & INLINE_HINT_known_hot)
794 && growth >= ((hints & (INLINE_HINT_indirect_call
795 | INLINE_HINT_loop_iterations
796 | INLINE_HINT_array_index
797 | INLINE_HINT_loop_stride))
798 ? MAX (MAX_INLINE_INSNS_AUTO,
799 MAX_INLINE_INSNS_SINGLE)
800 : MAX_INLINE_INSNS_AUTO))
802 /* growth_likely_positive is expensive, always test it last. */
803 if (growth >= MAX_INLINE_INSNS_SINGLE
804 || growth_likely_positive (callee, growth))
806 e->inline_failed = CIF_MAX_INLINE_INSNS_AUTO_LIMIT;
807 want_inline = false;
810 /* If call is cold, do not inline when function body would grow. */
811 else if (!e->maybe_hot_p ()
812 && (growth >= MAX_INLINE_INSNS_SINGLE
813 || growth_likely_positive (callee, growth)))
815 e->inline_failed = CIF_UNLIKELY_CALL;
816 want_inline = false;
819 if (!want_inline && report)
820 report_inline_failed_reason (e);
821 return want_inline;
824 /* EDGE is self recursive edge.
825 We hand two cases - when function A is inlining into itself
826 or when function A is being inlined into another inliner copy of function
827 A within function B.
829 In first case OUTER_NODE points to the toplevel copy of A, while
830 in the second case OUTER_NODE points to the outermost copy of A in B.
832 In both cases we want to be extra selective since
833 inlining the call will just introduce new recursive calls to appear. */
835 static bool
836 want_inline_self_recursive_call_p (struct cgraph_edge *edge,
837 struct cgraph_node *outer_node,
838 bool peeling,
839 int depth)
841 char const *reason = NULL;
842 bool want_inline = true;
843 int caller_freq = CGRAPH_FREQ_BASE;
844 int max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO);
846 if (DECL_DECLARED_INLINE_P (edge->caller->decl))
847 max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH);
849 if (!edge->maybe_hot_p ())
851 reason = "recursive call is cold";
852 want_inline = false;
854 else if (max_count && !outer_node->count)
856 reason = "not executed in profile";
857 want_inline = false;
859 else if (depth > max_depth)
861 reason = "--param max-inline-recursive-depth exceeded.";
862 want_inline = false;
865 if (outer_node->global.inlined_to)
866 caller_freq = outer_node->callers->frequency;
868 if (!caller_freq)
870 reason = "function is inlined and unlikely";
871 want_inline = false;
874 if (!want_inline)
876 /* Inlining of self recursive function into copy of itself within other function
877 is transformation similar to loop peeling.
879 Peeling is profitable if we can inline enough copies to make probability
880 of actual call to the self recursive function very small. Be sure that
881 the probability of recursion is small.
883 We ensure that the frequency of recursing is at most 1 - (1/max_depth).
884 This way the expected number of recision is at most max_depth. */
885 else if (peeling)
887 int max_prob = CGRAPH_FREQ_BASE - ((CGRAPH_FREQ_BASE + max_depth - 1)
888 / max_depth);
889 int i;
890 for (i = 1; i < depth; i++)
891 max_prob = max_prob * max_prob / CGRAPH_FREQ_BASE;
892 if (max_count
893 && (edge->count * CGRAPH_FREQ_BASE / outer_node->count
894 >= max_prob))
896 reason = "profile of recursive call is too large";
897 want_inline = false;
899 if (!max_count
900 && (edge->frequency * CGRAPH_FREQ_BASE / caller_freq
901 >= max_prob))
903 reason = "frequency of recursive call is too large";
904 want_inline = false;
907 /* Recursive inlining, i.e. equivalent of unrolling, is profitable if recursion
908 depth is large. We reduce function call overhead and increase chances that
909 things fit in hardware return predictor.
911 Recursive inlining might however increase cost of stack frame setup
912 actually slowing down functions whose recursion tree is wide rather than
913 deep.
915 Deciding reliably on when to do recursive inlining without profile feedback
916 is tricky. For now we disable recursive inlining when probability of self
917 recursion is low.
919 Recursive inlining of self recursive call within loop also results in large loop
920 depths that generally optimize badly. We may want to throttle down inlining
921 in those cases. In particular this seems to happen in one of libstdc++ rb tree
922 methods. */
923 else
925 if (max_count
926 && (edge->count * 100 / outer_node->count
927 <= PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY)))
929 reason = "profile of recursive call is too small";
930 want_inline = false;
932 else if (!max_count
933 && (edge->frequency * 100 / caller_freq
934 <= PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY)))
936 reason = "frequency of recursive call is too small";
937 want_inline = false;
940 if (!want_inline && dump_file)
941 fprintf (dump_file, " not inlining recursively: %s\n", reason);
942 return want_inline;
945 /* Return true when NODE has uninlinable caller;
946 set HAS_HOT_CALL if it has hot call.
947 Worker for cgraph_for_node_and_aliases. */
949 static bool
950 check_callers (struct cgraph_node *node, void *has_hot_call)
952 struct cgraph_edge *e;
953 for (e = node->callers; e; e = e->next_caller)
955 if (!opt_for_fn (e->caller->decl, flag_inline_functions_called_once))
956 return true;
957 if (!can_inline_edge_p (e, true))
958 return true;
959 if (e->recursive_p ())
960 return true;
961 if (!(*(bool *)has_hot_call) && e->maybe_hot_p ())
962 *(bool *)has_hot_call = true;
964 return false;
967 /* If NODE has a caller, return true. */
969 static bool
970 has_caller_p (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
972 if (node->callers)
973 return true;
974 return false;
977 /* Decide if inlining NODE would reduce unit size by eliminating
978 the offline copy of function.
979 When COLD is true the cold calls are considered, too. */
981 static bool
982 want_inline_function_to_all_callers_p (struct cgraph_node *node, bool cold)
984 bool has_hot_call = false;
986 /* Aliases gets inlined along with the function they alias. */
987 if (node->alias)
988 return false;
989 /* Already inlined? */
990 if (node->global.inlined_to)
991 return false;
992 /* Does it have callers? */
993 if (!node->call_for_symbol_and_aliases (has_caller_p, NULL, true))
994 return false;
995 /* Inlining into all callers would increase size? */
996 if (estimate_growth (node) > 0)
997 return false;
998 /* All inlines must be possible. */
999 if (node->call_for_symbol_and_aliases (check_callers, &has_hot_call,
1000 true))
1001 return false;
1002 if (!cold && !has_hot_call)
1003 return false;
1004 return true;
1007 /* A cost model driving the inlining heuristics in a way so the edges with
1008 smallest badness are inlined first. After each inlining is performed
1009 the costs of all caller edges of nodes affected are recomputed so the
1010 metrics may accurately depend on values such as number of inlinable callers
1011 of the function or function body size. */
1013 static sreal
1014 edge_badness (struct cgraph_edge *edge, bool dump)
1016 sreal badness;
1017 int growth, edge_time;
1018 struct cgraph_node *callee = edge->callee->ultimate_alias_target ();
1019 struct inline_summary *callee_info = inline_summaries->get (callee);
1020 inline_hints hints;
1021 cgraph_node *caller = (edge->caller->global.inlined_to
1022 ? edge->caller->global.inlined_to
1023 : edge->caller);
1025 growth = estimate_edge_growth (edge);
1026 edge_time = estimate_edge_time (edge);
1027 hints = estimate_edge_hints (edge);
1028 gcc_checking_assert (edge_time >= 0);
1029 gcc_checking_assert (edge_time <= callee_info->time);
1030 gcc_checking_assert (growth <= callee_info->size);
1032 if (dump)
1034 fprintf (dump_file, " Badness calculation for %s/%i -> %s/%i\n",
1035 xstrdup_for_dump (edge->caller->name ()),
1036 edge->caller->order,
1037 xstrdup_for_dump (callee->name ()),
1038 edge->callee->order);
1039 fprintf (dump_file, " size growth %i, time %i ",
1040 growth,
1041 edge_time);
1042 dump_inline_hints (dump_file, hints);
1043 if (big_speedup_p (edge))
1044 fprintf (dump_file, " big_speedup");
1045 fprintf (dump_file, "\n");
1048 /* Always prefer inlining saving code size. */
1049 if (growth <= 0)
1051 badness = (sreal) (-SREAL_MIN_SIG + growth) << (SREAL_MAX_EXP / 256);
1052 if (dump)
1053 fprintf (dump_file, " %f: Growth %d <= 0\n", badness.to_double (),
1054 growth);
1056 /* Inlining into EXTERNAL functions is not going to change anything unless
1057 they are themselves inlined. */
1058 else if (DECL_EXTERNAL (caller->decl))
1060 if (dump)
1061 fprintf (dump_file, " max: function is external\n");
1062 return sreal::max ();
1064 /* When profile is available. Compute badness as:
1066 time_saved * caller_count
1067 goodness = -------------------------------------------------
1068 growth_of_caller * overall_growth * combined_size
1070 badness = - goodness
1072 Again use negative value to make calls with profile appear hotter
1073 then calls without.
1075 else if (opt_for_fn (caller->decl, flag_guess_branch_prob) || caller->count)
1077 sreal numerator, denominator;
1078 int overall_growth;
1080 numerator = (compute_uninlined_call_time (callee_info, edge)
1081 - compute_inlined_call_time (edge, edge_time));
1082 if (numerator == 0)
1083 numerator = ((sreal) 1 >> 8);
1084 if (caller->count)
1085 numerator *= caller->count;
1086 else if (opt_for_fn (caller->decl, flag_branch_probabilities))
1087 numerator = numerator >> 11;
1088 denominator = growth;
1090 overall_growth = callee_info->growth;
1092 /* Look for inliner wrappers of the form:
1094 inline_caller ()
1096 do_fast_job...
1097 if (need_more_work)
1098 noninline_callee ();
1100 Withhout panilizing this case, we usually inline noninline_callee
1101 into the inline_caller because overall_growth is small preventing
1102 further inlining of inline_caller.
1104 Penalize only callgraph edges to functions with small overall
1105 growth ...
1107 if (growth > overall_growth
1108 /* ... and having only one caller which is not inlined ... */
1109 && callee_info->single_caller
1110 && !edge->caller->global.inlined_to
1111 /* ... and edges executed only conditionally ... */
1112 && edge->frequency < CGRAPH_FREQ_BASE
1113 /* ... consider case where callee is not inline but caller is ... */
1114 && ((!DECL_DECLARED_INLINE_P (edge->callee->decl)
1115 && DECL_DECLARED_INLINE_P (caller->decl))
1116 /* ... or when early optimizers decided to split and edge
1117 frequency still indicates splitting is a win ... */
1118 || (callee->split_part && !caller->split_part
1119 && edge->frequency
1120 < CGRAPH_FREQ_BASE
1121 * PARAM_VALUE
1122 (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY) / 100
1123 /* ... and do not overwrite user specified hints. */
1124 && (!DECL_DECLARED_INLINE_P (edge->callee->decl)
1125 || DECL_DECLARED_INLINE_P (caller->decl)))))
1127 struct inline_summary *caller_info = inline_summaries->get (caller);
1128 int caller_growth = caller_info->growth;
1130 /* Only apply the penalty when caller looks like inline candidate,
1131 and it is not called once and. */
1132 if (!caller_info->single_caller && overall_growth < caller_growth
1133 && caller_info->inlinable
1134 && caller_info->size
1135 < (DECL_DECLARED_INLINE_P (caller->decl)
1136 ? MAX_INLINE_INSNS_SINGLE : MAX_INLINE_INSNS_AUTO))
1138 if (dump)
1139 fprintf (dump_file,
1140 " Wrapper penalty. Increasing growth %i to %i\n",
1141 overall_growth, caller_growth);
1142 overall_growth = caller_growth;
1145 if (overall_growth > 0)
1147 /* Strongly preffer functions with few callers that can be inlined
1148 fully. The square root here leads to smaller binaries at average.
1149 Watch however for extreme cases and return to linear function
1150 when growth is large. */
1151 if (overall_growth < 256)
1152 overall_growth *= overall_growth;
1153 else
1154 overall_growth += 256 * 256 - 256;
1155 denominator *= overall_growth;
1157 denominator *= inline_summaries->get (caller)->self_size + growth;
1159 badness = - numerator / denominator;
1161 if (dump)
1163 fprintf (dump_file,
1164 " %f: guessed profile. frequency %f, count %" PRId64
1165 " caller count %" PRId64
1166 " time w/o inlining %f, time w inlining %f"
1167 " overall growth %i (current) %i (original)"
1168 " %i (compensated)\n",
1169 badness.to_double (),
1170 (double)edge->frequency / CGRAPH_FREQ_BASE,
1171 edge->count, caller->count,
1172 compute_uninlined_call_time (callee_info, edge).to_double (),
1173 compute_inlined_call_time (edge, edge_time).to_double (),
1174 estimate_growth (callee),
1175 callee_info->growth, overall_growth);
1178 /* When function local profile is not available or it does not give
1179 useful information (ie frequency is zero), base the cost on
1180 loop nest and overall size growth, so we optimize for overall number
1181 of functions fully inlined in program. */
1182 else
1184 int nest = MIN (inline_edge_summary (edge)->loop_depth, 8);
1185 badness = growth;
1187 /* Decrease badness if call is nested. */
1188 if (badness > 0)
1189 badness = badness >> nest;
1190 else
1191 badness = badness << nest;
1192 if (dump)
1193 fprintf (dump_file, " %f: no profile. nest %i\n",
1194 badness.to_double (), nest);
1196 gcc_checking_assert (badness != 0);
1198 if (edge->recursive_p ())
1199 badness = badness.shift (badness > 0 ? 4 : -4);
1200 if ((hints & (INLINE_HINT_indirect_call
1201 | INLINE_HINT_loop_iterations
1202 | INLINE_HINT_array_index
1203 | INLINE_HINT_loop_stride))
1204 || callee_info->growth <= 0)
1205 badness = badness.shift (badness > 0 ? -2 : 2);
1206 if (hints & (INLINE_HINT_same_scc))
1207 badness = badness.shift (badness > 0 ? 3 : -3);
1208 else if (hints & (INLINE_HINT_in_scc))
1209 badness = badness.shift (badness > 0 ? 2 : -2);
1210 else if (hints & (INLINE_HINT_cross_module))
1211 badness = badness.shift (badness > 0 ? 1 : -1);
1212 if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
1213 badness = badness.shift (badness > 0 ? -4 : 4);
1214 else if ((hints & INLINE_HINT_declared_inline))
1215 badness = badness.shift (badness > 0 ? -3 : 3);
1216 if (dump)
1217 fprintf (dump_file, " Adjusted by hints %f\n", badness.to_double ());
1218 return badness;
1221 /* Recompute badness of EDGE and update its key in HEAP if needed. */
1222 static inline void
1223 update_edge_key (edge_heap_t *heap, struct cgraph_edge *edge)
1225 sreal badness = edge_badness (edge, false);
1226 if (edge->aux)
1228 edge_heap_node_t *n = (edge_heap_node_t *) edge->aux;
1229 gcc_checking_assert (n->get_data () == edge);
1231 /* fibonacci_heap::replace_key does busy updating of the
1232 heap that is unnecesarily expensive.
1233 We do lazy increases: after extracting minimum if the key
1234 turns out to be out of date, it is re-inserted into heap
1235 with correct value. */
1236 if (badness < n->get_key ())
1238 if (dump_file && (dump_flags & TDF_DETAILS))
1240 fprintf (dump_file,
1241 " decreasing badness %s/%i -> %s/%i, %f"
1242 " to %f\n",
1243 xstrdup_for_dump (edge->caller->name ()),
1244 edge->caller->order,
1245 xstrdup_for_dump (edge->callee->name ()),
1246 edge->callee->order,
1247 n->get_key ().to_double (),
1248 badness.to_double ());
1250 heap->decrease_key (n, badness);
1253 else
1255 if (dump_file && (dump_flags & TDF_DETAILS))
1257 fprintf (dump_file,
1258 " enqueuing call %s/%i -> %s/%i, badness %f\n",
1259 xstrdup_for_dump (edge->caller->name ()),
1260 edge->caller->order,
1261 xstrdup_for_dump (edge->callee->name ()),
1262 edge->callee->order,
1263 badness.to_double ());
1265 edge->aux = heap->insert (badness, edge);
1270 /* NODE was inlined.
1271 All caller edges needs to be resetted because
1272 size estimates change. Similarly callees needs reset
1273 because better context may be known. */
1275 static void
1276 reset_edge_caches (struct cgraph_node *node)
1278 struct cgraph_edge *edge;
1279 struct cgraph_edge *e = node->callees;
1280 struct cgraph_node *where = node;
1281 struct ipa_ref *ref;
1283 if (where->global.inlined_to)
1284 where = where->global.inlined_to;
1286 for (edge = where->callers; edge; edge = edge->next_caller)
1287 if (edge->inline_failed)
1288 reset_edge_growth_cache (edge);
1290 FOR_EACH_ALIAS (where, ref)
1291 reset_edge_caches (dyn_cast <cgraph_node *> (ref->referring));
1293 if (!e)
1294 return;
1296 while (true)
1297 if (!e->inline_failed && e->callee->callees)
1298 e = e->callee->callees;
1299 else
1301 if (e->inline_failed)
1302 reset_edge_growth_cache (e);
1303 if (e->next_callee)
1304 e = e->next_callee;
1305 else
1309 if (e->caller == node)
1310 return;
1311 e = e->caller->callers;
1313 while (!e->next_callee);
1314 e = e->next_callee;
1319 /* Recompute HEAP nodes for each of caller of NODE.
1320 UPDATED_NODES track nodes we already visited, to avoid redundant work.
1321 When CHECK_INLINABLITY_FOR is set, re-check for specified edge that
1322 it is inlinable. Otherwise check all edges. */
1324 static void
1325 update_caller_keys (edge_heap_t *heap, struct cgraph_node *node,
1326 bitmap updated_nodes,
1327 struct cgraph_edge *check_inlinablity_for)
1329 struct cgraph_edge *edge;
1330 struct ipa_ref *ref;
1332 if ((!node->alias && !inline_summaries->get (node)->inlinable)
1333 || node->global.inlined_to)
1334 return;
1335 if (!bitmap_set_bit (updated_nodes, node->uid))
1336 return;
1338 FOR_EACH_ALIAS (node, ref)
1340 struct cgraph_node *alias = dyn_cast <cgraph_node *> (ref->referring);
1341 update_caller_keys (heap, alias, updated_nodes, check_inlinablity_for);
1344 for (edge = node->callers; edge; edge = edge->next_caller)
1345 if (edge->inline_failed)
1347 if (!check_inlinablity_for
1348 || check_inlinablity_for == edge)
1350 if (can_inline_edge_p (edge, false)
1351 && want_inline_small_function_p (edge, false))
1352 update_edge_key (heap, edge);
1353 else if (edge->aux)
1355 report_inline_failed_reason (edge);
1356 heap->delete_node ((edge_heap_node_t *) edge->aux);
1357 edge->aux = NULL;
1360 else if (edge->aux)
1361 update_edge_key (heap, edge);
1365 /* Recompute HEAP nodes for each uninlined call in NODE.
1366 This is used when we know that edge badnesses are going only to increase
1367 (we introduced new call site) and thus all we need is to insert newly
1368 created edges into heap. */
1370 static void
1371 update_callee_keys (edge_heap_t *heap, struct cgraph_node *node,
1372 bitmap updated_nodes)
1374 struct cgraph_edge *e = node->callees;
1376 if (!e)
1377 return;
1378 while (true)
1379 if (!e->inline_failed && e->callee->callees)
1380 e = e->callee->callees;
1381 else
1383 enum availability avail;
1384 struct cgraph_node *callee;
1385 /* We do not reset callee growth cache here. Since we added a new call,
1386 growth chould have just increased and consequentely badness metric
1387 don't need updating. */
1388 if (e->inline_failed
1389 && (callee = e->callee->ultimate_alias_target (&avail))
1390 && inline_summaries->get (callee)->inlinable
1391 && avail >= AVAIL_AVAILABLE
1392 && !bitmap_bit_p (updated_nodes, callee->uid))
1394 if (can_inline_edge_p (e, false)
1395 && want_inline_small_function_p (e, false))
1396 update_edge_key (heap, e);
1397 else if (e->aux)
1399 report_inline_failed_reason (e);
1400 heap->delete_node ((edge_heap_node_t *) e->aux);
1401 e->aux = NULL;
1404 if (e->next_callee)
1405 e = e->next_callee;
1406 else
1410 if (e->caller == node)
1411 return;
1412 e = e->caller->callers;
1414 while (!e->next_callee);
1415 e = e->next_callee;
1420 /* Enqueue all recursive calls from NODE into priority queue depending on
1421 how likely we want to recursively inline the call. */
1423 static void
1424 lookup_recursive_calls (struct cgraph_node *node, struct cgraph_node *where,
1425 edge_heap_t *heap)
1427 struct cgraph_edge *e;
1428 enum availability avail;
1430 for (e = where->callees; e; e = e->next_callee)
1431 if (e->callee == node
1432 || (e->callee->ultimate_alias_target (&avail) == node
1433 && avail > AVAIL_INTERPOSABLE))
1435 /* When profile feedback is available, prioritize by expected number
1436 of calls. */
1437 heap->insert (!max_count ? -e->frequency
1438 : -(e->count / ((max_count + (1<<24) - 1) / (1<<24))),
1441 for (e = where->callees; e; e = e->next_callee)
1442 if (!e->inline_failed)
1443 lookup_recursive_calls (node, e->callee, heap);
1446 /* Decide on recursive inlining: in the case function has recursive calls,
1447 inline until body size reaches given argument. If any new indirect edges
1448 are discovered in the process, add them to *NEW_EDGES, unless NEW_EDGES
1449 is NULL. */
1451 static bool
1452 recursive_inlining (struct cgraph_edge *edge,
1453 vec<cgraph_edge *> *new_edges)
1455 int limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO);
1456 edge_heap_t heap (sreal::min ());
1457 struct cgraph_node *node;
1458 struct cgraph_edge *e;
1459 struct cgraph_node *master_clone = NULL, *next;
1460 int depth = 0;
1461 int n = 0;
1463 node = edge->caller;
1464 if (node->global.inlined_to)
1465 node = node->global.inlined_to;
1467 if (DECL_DECLARED_INLINE_P (node->decl))
1468 limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE);
1470 /* Make sure that function is small enough to be considered for inlining. */
1471 if (estimate_size_after_inlining (node, edge) >= limit)
1472 return false;
1473 lookup_recursive_calls (node, node, &heap);
1474 if (heap.empty ())
1475 return false;
1477 if (dump_file)
1478 fprintf (dump_file,
1479 " Performing recursive inlining on %s\n",
1480 node->name ());
1482 /* Do the inlining and update list of recursive call during process. */
1483 while (!heap.empty ())
1485 struct cgraph_edge *curr = heap.extract_min ();
1486 struct cgraph_node *cnode, *dest = curr->callee;
1488 if (!can_inline_edge_p (curr, true))
1489 continue;
1491 /* MASTER_CLONE is produced in the case we already started modified
1492 the function. Be sure to redirect edge to the original body before
1493 estimating growths otherwise we will be seeing growths after inlining
1494 the already modified body. */
1495 if (master_clone)
1497 curr->redirect_callee (master_clone);
1498 reset_edge_growth_cache (curr);
1501 if (estimate_size_after_inlining (node, curr) > limit)
1503 curr->redirect_callee (dest);
1504 reset_edge_growth_cache (curr);
1505 break;
1508 depth = 1;
1509 for (cnode = curr->caller;
1510 cnode->global.inlined_to; cnode = cnode->callers->caller)
1511 if (node->decl
1512 == curr->callee->ultimate_alias_target ()->decl)
1513 depth++;
1515 if (!want_inline_self_recursive_call_p (curr, node, false, depth))
1517 curr->redirect_callee (dest);
1518 reset_edge_growth_cache (curr);
1519 continue;
1522 if (dump_file)
1524 fprintf (dump_file,
1525 " Inlining call of depth %i", depth);
1526 if (node->count)
1528 fprintf (dump_file, " called approx. %.2f times per call",
1529 (double)curr->count / node->count);
1531 fprintf (dump_file, "\n");
1533 if (!master_clone)
1535 /* We need original clone to copy around. */
1536 master_clone = node->create_clone (node->decl, node->count,
1537 CGRAPH_FREQ_BASE, false, vNULL,
1538 true, NULL, NULL);
1539 for (e = master_clone->callees; e; e = e->next_callee)
1540 if (!e->inline_failed)
1541 clone_inlined_nodes (e, true, false, NULL, CGRAPH_FREQ_BASE);
1542 curr->redirect_callee (master_clone);
1543 reset_edge_growth_cache (curr);
1546 inline_call (curr, false, new_edges, &overall_size, true);
1547 lookup_recursive_calls (node, curr->callee, &heap);
1548 n++;
1551 if (!heap.empty () && dump_file)
1552 fprintf (dump_file, " Recursive inlining growth limit met.\n");
1554 if (!master_clone)
1555 return false;
1557 if (dump_file)
1558 fprintf (dump_file,
1559 "\n Inlined %i times, "
1560 "body grown from size %i to %i, time %i to %i\n", n,
1561 inline_summaries->get (master_clone)->size, inline_summaries->get (node)->size,
1562 inline_summaries->get (master_clone)->time, inline_summaries->get (node)->time);
1564 /* Remove master clone we used for inlining. We rely that clones inlined
1565 into master clone gets queued just before master clone so we don't
1566 need recursion. */
1567 for (node = symtab->first_function (); node != master_clone;
1568 node = next)
1570 next = symtab->next_function (node);
1571 if (node->global.inlined_to == master_clone)
1572 node->remove ();
1574 master_clone->remove ();
1575 return true;
1579 /* Given whole compilation unit estimate of INSNS, compute how large we can
1580 allow the unit to grow. */
1582 static int
1583 compute_max_insns (int insns)
1585 int max_insns = insns;
1586 if (max_insns < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS))
1587 max_insns = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS);
1589 return ((int64_t) max_insns
1590 * (100 + PARAM_VALUE (PARAM_INLINE_UNIT_GROWTH)) / 100);
1594 /* Compute badness of all edges in NEW_EDGES and add them to the HEAP. */
1596 static void
1597 add_new_edges_to_heap (edge_heap_t *heap, vec<cgraph_edge *> new_edges)
1599 while (new_edges.length () > 0)
1601 struct cgraph_edge *edge = new_edges.pop ();
1603 gcc_assert (!edge->aux);
1604 if (edge->inline_failed
1605 && can_inline_edge_p (edge, true)
1606 && want_inline_small_function_p (edge, true))
1607 edge->aux = heap->insert (edge_badness (edge, false), edge);
1611 /* Remove EDGE from the fibheap. */
1613 static void
1614 heap_edge_removal_hook (struct cgraph_edge *e, void *data)
1616 if (e->aux)
1618 ((edge_heap_t *)data)->delete_node ((edge_heap_node_t *)e->aux);
1619 e->aux = NULL;
1623 /* Return true if speculation of edge E seems useful.
1624 If ANTICIPATE_INLINING is true, be conservative and hope that E
1625 may get inlined. */
1627 bool
1628 speculation_useful_p (struct cgraph_edge *e, bool anticipate_inlining)
1630 enum availability avail;
1631 struct cgraph_node *target = e->callee->ultimate_alias_target (&avail);
1632 struct cgraph_edge *direct, *indirect;
1633 struct ipa_ref *ref;
1635 gcc_assert (e->speculative && !e->indirect_unknown_callee);
1637 if (!e->maybe_hot_p ())
1638 return false;
1640 /* See if IP optimizations found something potentially useful about the
1641 function. For now we look only for CONST/PURE flags. Almost everything
1642 else we propagate is useless. */
1643 if (avail >= AVAIL_AVAILABLE)
1645 int ecf_flags = flags_from_decl_or_type (target->decl);
1646 if (ecf_flags & ECF_CONST)
1648 e->speculative_call_info (direct, indirect, ref);
1649 if (!(indirect->indirect_info->ecf_flags & ECF_CONST))
1650 return true;
1652 else if (ecf_flags & ECF_PURE)
1654 e->speculative_call_info (direct, indirect, ref);
1655 if (!(indirect->indirect_info->ecf_flags & ECF_PURE))
1656 return true;
1659 /* If we did not managed to inline the function nor redirect
1660 to an ipa-cp clone (that are seen by having local flag set),
1661 it is probably pointless to inline it unless hardware is missing
1662 indirect call predictor. */
1663 if (!anticipate_inlining && e->inline_failed && !target->local.local)
1664 return false;
1665 /* For overwritable targets there is not much to do. */
1666 if (e->inline_failed && !can_inline_edge_p (e, false, true))
1667 return false;
1668 /* OK, speculation seems interesting. */
1669 return true;
1672 /* We know that EDGE is not going to be inlined.
1673 See if we can remove speculation. */
1675 static void
1676 resolve_noninline_speculation (edge_heap_t *edge_heap, struct cgraph_edge *edge)
1678 if (edge->speculative && !speculation_useful_p (edge, false))
1680 struct cgraph_node *node = edge->caller;
1681 struct cgraph_node *where = node->global.inlined_to
1682 ? node->global.inlined_to : node;
1683 bitmap updated_nodes = BITMAP_ALLOC (NULL);
1685 spec_rem += edge->count;
1686 edge->resolve_speculation ();
1687 reset_edge_caches (where);
1688 inline_update_overall_summary (where);
1689 update_caller_keys (edge_heap, where,
1690 updated_nodes, NULL);
1691 update_callee_keys (edge_heap, where,
1692 updated_nodes);
1693 BITMAP_FREE (updated_nodes);
1697 /* Return true if NODE should be accounted for overall size estimate.
1698 Skip all nodes optimized for size so we can measure the growth of hot
1699 part of program no matter of the padding. */
1701 bool
1702 inline_account_function_p (struct cgraph_node *node)
1704 return (!DECL_EXTERNAL (node->decl)
1705 && !opt_for_fn (node->decl, optimize_size)
1706 && node->frequency != NODE_FREQUENCY_UNLIKELY_EXECUTED);
1709 /* Count number of callers of NODE and store it into DATA (that
1710 points to int. Worker for cgraph_for_node_and_aliases. */
1712 static bool
1713 sum_callers (struct cgraph_node *node, void *data)
1715 struct cgraph_edge *e;
1716 int *num_calls = (int *)data;
1718 for (e = node->callers; e; e = e->next_caller)
1719 (*num_calls)++;
1720 return false;
1723 /* We use greedy algorithm for inlining of small functions:
1724 All inline candidates are put into prioritized heap ordered in
1725 increasing badness.
1727 The inlining of small functions is bounded by unit growth parameters. */
1729 static void
1730 inline_small_functions (void)
1732 struct cgraph_node *node;
1733 struct cgraph_edge *edge;
1734 edge_heap_t edge_heap (sreal::min ());
1735 bitmap updated_nodes = BITMAP_ALLOC (NULL);
1736 int min_size, max_size;
1737 auto_vec<cgraph_edge *> new_indirect_edges;
1738 int initial_size = 0;
1739 struct cgraph_node **order = XCNEWVEC (cgraph_node *, symtab->cgraph_count);
1740 struct cgraph_edge_hook_list *edge_removal_hook_holder;
1741 new_indirect_edges.create (8);
1743 edge_removal_hook_holder
1744 = symtab->add_edge_removal_hook (&heap_edge_removal_hook, &edge_heap);
1746 /* Compute overall unit size and other global parameters used by badness
1747 metrics. */
1749 max_count = 0;
1750 ipa_reduced_postorder (order, true, true, NULL);
1751 free (order);
1753 FOR_EACH_DEFINED_FUNCTION (node)
1754 if (!node->global.inlined_to)
1756 if (!node->alias && node->analyzed
1757 && (node->has_gimple_body_p () || node->thunk.thunk_p))
1759 struct inline_summary *info = inline_summaries->get (node);
1760 struct ipa_dfs_info *dfs = (struct ipa_dfs_info *) node->aux;
1762 /* Do not account external functions, they will be optimized out
1763 if not inlined. Also only count the non-cold portion of program. */
1764 if (inline_account_function_p (node))
1765 initial_size += info->size;
1766 info->growth = estimate_growth (node);
1768 int num_calls = 0;
1769 node->call_for_symbol_and_aliases (sum_callers, &num_calls,
1770 true);
1771 if (num_calls == 1)
1772 info->single_caller = true;
1773 if (dfs && dfs->next_cycle)
1775 struct cgraph_node *n2;
1776 int id = dfs->scc_no + 1;
1777 for (n2 = node; n2;
1778 n2 = ((struct ipa_dfs_info *) node->aux)->next_cycle)
1780 struct inline_summary *info2 = inline_summaries->get (n2);
1781 if (info2->scc_no)
1782 break;
1783 info2->scc_no = id;
1788 for (edge = node->callers; edge; edge = edge->next_caller)
1789 if (max_count < edge->count)
1790 max_count = edge->count;
1792 ipa_free_postorder_info ();
1793 initialize_growth_caches ();
1795 if (dump_file)
1796 fprintf (dump_file,
1797 "\nDeciding on inlining of small functions. Starting with size %i.\n",
1798 initial_size);
1800 overall_size = initial_size;
1801 max_size = compute_max_insns (overall_size);
1802 min_size = overall_size;
1804 /* Populate the heap with all edges we might inline. */
1806 FOR_EACH_DEFINED_FUNCTION (node)
1808 bool update = false;
1809 struct cgraph_edge *next = NULL;
1810 bool has_speculative = false;
1812 if (dump_file)
1813 fprintf (dump_file, "Enqueueing calls in %s/%i.\n",
1814 node->name (), node->order);
1816 for (edge = node->callees; edge; edge = next)
1818 next = edge->next_callee;
1819 if (edge->inline_failed
1820 && !edge->aux
1821 && can_inline_edge_p (edge, true)
1822 && want_inline_small_function_p (edge, true)
1823 && edge->inline_failed)
1825 gcc_assert (!edge->aux);
1826 update_edge_key (&edge_heap, edge);
1828 if (edge->speculative)
1829 has_speculative = true;
1831 if (has_speculative)
1832 for (edge = node->callees; edge; edge = next)
1833 if (edge->speculative && !speculation_useful_p (edge,
1834 edge->aux != NULL))
1836 edge->resolve_speculation ();
1837 update = true;
1839 if (update)
1841 struct cgraph_node *where = node->global.inlined_to
1842 ? node->global.inlined_to : node;
1843 inline_update_overall_summary (where);
1844 reset_edge_caches (where);
1845 update_caller_keys (&edge_heap, where,
1846 updated_nodes, NULL);
1847 update_callee_keys (&edge_heap, where,
1848 updated_nodes);
1849 bitmap_clear (updated_nodes);
1853 gcc_assert (in_lto_p
1854 || !max_count
1855 || (profile_info && flag_branch_probabilities));
1857 while (!edge_heap.empty ())
1859 int old_size = overall_size;
1860 struct cgraph_node *where, *callee;
1861 sreal badness = edge_heap.min_key ();
1862 sreal current_badness;
1863 int growth;
1865 edge = edge_heap.extract_min ();
1866 gcc_assert (edge->aux);
1867 edge->aux = NULL;
1868 if (!edge->inline_failed || !edge->callee->analyzed)
1869 continue;
1871 #if CHECKING_P
1872 /* Be sure that caches are maintained consistent. */
1873 sreal cached_badness = edge_badness (edge, false);
1875 int old_size_est = estimate_edge_size (edge);
1876 int old_time_est = estimate_edge_time (edge);
1877 int old_hints_est = estimate_edge_hints (edge);
1879 reset_edge_growth_cache (edge);
1880 gcc_assert (old_size_est == estimate_edge_size (edge));
1881 gcc_assert (old_time_est == estimate_edge_time (edge));
1882 /* FIXME:
1884 gcc_assert (old_hints_est == estimate_edge_hints (edge));
1886 fails with profile feedback because some hints depends on
1887 maybe_hot_edge_p predicate and because callee gets inlined to other
1888 calls, the edge may become cold.
1889 This ought to be fixed by computing relative probabilities
1890 for given invocation but that will be better done once whole
1891 code is converted to sreals. Disable for now and revert to "wrong"
1892 value so enable/disable checking paths agree. */
1893 edge_growth_cache[edge->uid].hints = old_hints_est + 1;
1895 /* When updating the edge costs, we only decrease badness in the keys.
1896 Increases of badness are handled lazilly; when we see key with out
1897 of date value on it, we re-insert it now. */
1898 current_badness = edge_badness (edge, false);
1899 /* Disable checking for profile because roundoff errors may cause slight
1900 deviations in the order. */
1901 gcc_assert (max_count || cached_badness == current_badness);
1902 gcc_assert (current_badness >= badness);
1903 #else
1904 current_badness = edge_badness (edge, false);
1905 #endif
1906 if (current_badness != badness)
1908 if (edge_heap.min () && current_badness > edge_heap.min_key ())
1910 edge->aux = edge_heap.insert (current_badness, edge);
1911 continue;
1913 else
1914 badness = current_badness;
1917 if (!can_inline_edge_p (edge, true))
1919 resolve_noninline_speculation (&edge_heap, edge);
1920 continue;
1923 callee = edge->callee->ultimate_alias_target ();
1924 growth = estimate_edge_growth (edge);
1925 if (dump_file)
1927 fprintf (dump_file,
1928 "\nConsidering %s/%i with %i size\n",
1929 callee->name (), callee->order,
1930 inline_summaries->get (callee)->size);
1931 fprintf (dump_file,
1932 " to be inlined into %s/%i in %s:%i\n"
1933 " Estimated badness is %f, frequency %.2f.\n",
1934 edge->caller->name (), edge->caller->order,
1935 edge->call_stmt
1936 && (LOCATION_LOCUS (gimple_location ((const gimple *)
1937 edge->call_stmt))
1938 > BUILTINS_LOCATION)
1939 ? gimple_filename ((const gimple *) edge->call_stmt)
1940 : "unknown",
1941 edge->call_stmt
1942 ? gimple_lineno ((const gimple *) edge->call_stmt)
1943 : -1,
1944 badness.to_double (),
1945 edge->frequency / (double)CGRAPH_FREQ_BASE);
1946 if (edge->count)
1947 fprintf (dump_file," Called %" PRId64"x\n",
1948 edge->count);
1949 if (dump_flags & TDF_DETAILS)
1950 edge_badness (edge, true);
1953 if (overall_size + growth > max_size
1954 && !DECL_DISREGARD_INLINE_LIMITS (callee->decl))
1956 edge->inline_failed = CIF_INLINE_UNIT_GROWTH_LIMIT;
1957 report_inline_failed_reason (edge);
1958 resolve_noninline_speculation (&edge_heap, edge);
1959 continue;
1962 if (!want_inline_small_function_p (edge, true))
1964 resolve_noninline_speculation (&edge_heap, edge);
1965 continue;
1968 /* Heuristics for inlining small functions work poorly for
1969 recursive calls where we do effects similar to loop unrolling.
1970 When inlining such edge seems profitable, leave decision on
1971 specific inliner. */
1972 if (edge->recursive_p ())
1974 where = edge->caller;
1975 if (where->global.inlined_to)
1976 where = where->global.inlined_to;
1977 if (!recursive_inlining (edge,
1978 opt_for_fn (edge->caller->decl,
1979 flag_indirect_inlining)
1980 ? &new_indirect_edges : NULL))
1982 edge->inline_failed = CIF_RECURSIVE_INLINING;
1983 resolve_noninline_speculation (&edge_heap, edge);
1984 continue;
1986 reset_edge_caches (where);
1987 /* Recursive inliner inlines all recursive calls of the function
1988 at once. Consequently we need to update all callee keys. */
1989 if (opt_for_fn (edge->caller->decl, flag_indirect_inlining))
1990 add_new_edges_to_heap (&edge_heap, new_indirect_edges);
1991 update_callee_keys (&edge_heap, where, updated_nodes);
1992 bitmap_clear (updated_nodes);
1994 else
1996 struct cgraph_node *outer_node = NULL;
1997 int depth = 0;
1999 /* Consider the case where self recursive function A is inlined
2000 into B. This is desired optimization in some cases, since it
2001 leads to effect similar of loop peeling and we might completely
2002 optimize out the recursive call. However we must be extra
2003 selective. */
2005 where = edge->caller;
2006 while (where->global.inlined_to)
2008 if (where->decl == callee->decl)
2009 outer_node = where, depth++;
2010 where = where->callers->caller;
2012 if (outer_node
2013 && !want_inline_self_recursive_call_p (edge, outer_node,
2014 true, depth))
2016 edge->inline_failed
2017 = (DECL_DISREGARD_INLINE_LIMITS (edge->callee->decl)
2018 ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED);
2019 resolve_noninline_speculation (&edge_heap, edge);
2020 continue;
2022 else if (depth && dump_file)
2023 fprintf (dump_file, " Peeling recursion with depth %i\n", depth);
2025 gcc_checking_assert (!callee->global.inlined_to);
2026 inline_call (edge, true, &new_indirect_edges, &overall_size, true);
2027 add_new_edges_to_heap (&edge_heap, new_indirect_edges);
2029 reset_edge_caches (edge->callee->function_symbol ());
2031 update_callee_keys (&edge_heap, where, updated_nodes);
2033 where = edge->caller;
2034 if (where->global.inlined_to)
2035 where = where->global.inlined_to;
2037 /* Our profitability metric can depend on local properties
2038 such as number of inlinable calls and size of the function body.
2039 After inlining these properties might change for the function we
2040 inlined into (since it's body size changed) and for the functions
2041 called by function we inlined (since number of it inlinable callers
2042 might change). */
2043 update_caller_keys (&edge_heap, where, updated_nodes, NULL);
2044 /* Offline copy count has possibly changed, recompute if profile is
2045 available. */
2046 if (max_count)
2048 struct cgraph_node *n = cgraph_node::get (edge->callee->decl);
2049 if (n != edge->callee && n->analyzed)
2050 update_callee_keys (&edge_heap, n, updated_nodes);
2052 bitmap_clear (updated_nodes);
2054 if (dump_file)
2056 fprintf (dump_file,
2057 " Inlined into %s which now has time %i and size %i,"
2058 "net change of %+i.\n",
2059 edge->caller->name (),
2060 inline_summaries->get (edge->caller)->time,
2061 inline_summaries->get (edge->caller)->size,
2062 overall_size - old_size);
2064 if (min_size > overall_size)
2066 min_size = overall_size;
2067 max_size = compute_max_insns (min_size);
2069 if (dump_file)
2070 fprintf (dump_file, "New minimal size reached: %i\n", min_size);
2074 free_growth_caches ();
2075 if (dump_file)
2076 fprintf (dump_file,
2077 "Unit growth for small function inlining: %i->%i (%i%%)\n",
2078 initial_size, overall_size,
2079 initial_size ? overall_size * 100 / (initial_size) - 100: 0);
2080 BITMAP_FREE (updated_nodes);
2081 symtab->remove_edge_removal_hook (edge_removal_hook_holder);
2084 /* Flatten NODE. Performed both during early inlining and
2085 at IPA inlining time. */
2087 static void
2088 flatten_function (struct cgraph_node *node, bool early)
2090 struct cgraph_edge *e;
2092 /* We shouldn't be called recursively when we are being processed. */
2093 gcc_assert (node->aux == NULL);
2095 node->aux = (void *) node;
2097 for (e = node->callees; e; e = e->next_callee)
2099 struct cgraph_node *orig_callee;
2100 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
2102 /* We've hit cycle? It is time to give up. */
2103 if (callee->aux)
2105 if (dump_file)
2106 fprintf (dump_file,
2107 "Not inlining %s into %s to avoid cycle.\n",
2108 xstrdup_for_dump (callee->name ()),
2109 xstrdup_for_dump (e->caller->name ()));
2110 e->inline_failed = CIF_RECURSIVE_INLINING;
2111 continue;
2114 /* When the edge is already inlined, we just need to recurse into
2115 it in order to fully flatten the leaves. */
2116 if (!e->inline_failed)
2118 flatten_function (callee, early);
2119 continue;
2122 /* Flatten attribute needs to be processed during late inlining. For
2123 extra code quality we however do flattening during early optimization,
2124 too. */
2125 if (!early
2126 ? !can_inline_edge_p (e, true)
2127 : !can_early_inline_edge_p (e))
2128 continue;
2130 if (e->recursive_p ())
2132 if (dump_file)
2133 fprintf (dump_file, "Not inlining: recursive call.\n");
2134 continue;
2137 if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node->decl))
2138 != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->decl)))
2140 if (dump_file)
2141 fprintf (dump_file, "Not inlining: SSA form does not match.\n");
2142 continue;
2145 /* Inline the edge and flatten the inline clone. Avoid
2146 recursing through the original node if the node was cloned. */
2147 if (dump_file)
2148 fprintf (dump_file, " Inlining %s into %s.\n",
2149 xstrdup_for_dump (callee->name ()),
2150 xstrdup_for_dump (e->caller->name ()));
2151 orig_callee = callee;
2152 inline_call (e, true, NULL, NULL, false);
2153 if (e->callee != orig_callee)
2154 orig_callee->aux = (void *) node;
2155 flatten_function (e->callee, early);
2156 if (e->callee != orig_callee)
2157 orig_callee->aux = NULL;
2160 node->aux = NULL;
2161 if (!node->global.inlined_to)
2162 inline_update_overall_summary (node);
2165 /* Inline NODE to all callers. Worker for cgraph_for_node_and_aliases.
2166 DATA points to number of calls originally found so we avoid infinite
2167 recursion. */
2169 static bool
2170 inline_to_all_callers (struct cgraph_node *node, void *data)
2172 int *num_calls = (int *)data;
2173 bool callee_removed = false;
2175 while (node->callers && !node->global.inlined_to)
2177 struct cgraph_node *caller = node->callers->caller;
2179 if (!can_inline_edge_p (node->callers, true)
2180 || node->callers->recursive_p ())
2182 if (dump_file)
2183 fprintf (dump_file, "Uninlinable call found; giving up.\n");
2184 *num_calls = 0;
2185 return false;
2188 if (dump_file)
2190 fprintf (dump_file,
2191 "\nInlining %s size %i.\n",
2192 node->name (),
2193 inline_summaries->get (node)->size);
2194 fprintf (dump_file,
2195 " Called once from %s %i insns.\n",
2196 node->callers->caller->name (),
2197 inline_summaries->get (node->callers->caller)->size);
2200 inline_call (node->callers, true, NULL, NULL, true, &callee_removed);
2201 if (dump_file)
2202 fprintf (dump_file,
2203 " Inlined into %s which now has %i size\n",
2204 caller->name (),
2205 inline_summaries->get (caller)->size);
2206 if (!(*num_calls)--)
2208 if (dump_file)
2209 fprintf (dump_file, "New calls found; giving up.\n");
2210 return callee_removed;
2212 if (callee_removed)
2213 return true;
2215 return false;
2218 /* Output overall time estimate. */
2219 static void
2220 dump_overall_stats (void)
2222 int64_t sum_weighted = 0, sum = 0;
2223 struct cgraph_node *node;
2225 FOR_EACH_DEFINED_FUNCTION (node)
2226 if (!node->global.inlined_to
2227 && !node->alias)
2229 int time = inline_summaries->get (node)->time;
2230 sum += time;
2231 sum_weighted += time * node->count;
2233 fprintf (dump_file, "Overall time estimate: "
2234 "%" PRId64" weighted by profile: "
2235 "%" PRId64"\n", sum, sum_weighted);
2238 /* Output some useful stats about inlining. */
2240 static void
2241 dump_inline_stats (void)
2243 int64_t inlined_cnt = 0, inlined_indir_cnt = 0;
2244 int64_t inlined_virt_cnt = 0, inlined_virt_indir_cnt = 0;
2245 int64_t noninlined_cnt = 0, noninlined_indir_cnt = 0;
2246 int64_t noninlined_virt_cnt = 0, noninlined_virt_indir_cnt = 0;
2247 int64_t inlined_speculative = 0, inlined_speculative_ply = 0;
2248 int64_t indirect_poly_cnt = 0, indirect_cnt = 0;
2249 int64_t reason[CIF_N_REASONS][3];
2250 int i;
2251 struct cgraph_node *node;
2253 memset (reason, 0, sizeof (reason));
2254 FOR_EACH_DEFINED_FUNCTION (node)
2256 struct cgraph_edge *e;
2257 for (e = node->callees; e; e = e->next_callee)
2259 if (e->inline_failed)
2261 reason[(int) e->inline_failed][0] += e->count;
2262 reason[(int) e->inline_failed][1] += e->frequency;
2263 reason[(int) e->inline_failed][2] ++;
2264 if (DECL_VIRTUAL_P (e->callee->decl))
2266 if (e->indirect_inlining_edge)
2267 noninlined_virt_indir_cnt += e->count;
2268 else
2269 noninlined_virt_cnt += e->count;
2271 else
2273 if (e->indirect_inlining_edge)
2274 noninlined_indir_cnt += e->count;
2275 else
2276 noninlined_cnt += e->count;
2279 else
2281 if (e->speculative)
2283 if (DECL_VIRTUAL_P (e->callee->decl))
2284 inlined_speculative_ply += e->count;
2285 else
2286 inlined_speculative += e->count;
2288 else if (DECL_VIRTUAL_P (e->callee->decl))
2290 if (e->indirect_inlining_edge)
2291 inlined_virt_indir_cnt += e->count;
2292 else
2293 inlined_virt_cnt += e->count;
2295 else
2297 if (e->indirect_inlining_edge)
2298 inlined_indir_cnt += e->count;
2299 else
2300 inlined_cnt += e->count;
2304 for (e = node->indirect_calls; e; e = e->next_callee)
2305 if (e->indirect_info->polymorphic)
2306 indirect_poly_cnt += e->count;
2307 else
2308 indirect_cnt += e->count;
2310 if (max_count)
2312 fprintf (dump_file,
2313 "Inlined %" PRId64 " + speculative "
2314 "%" PRId64 " + speculative polymorphic "
2315 "%" PRId64 " + previously indirect "
2316 "%" PRId64 " + virtual "
2317 "%" PRId64 " + virtual and previously indirect "
2318 "%" PRId64 "\n" "Not inlined "
2319 "%" PRId64 " + previously indirect "
2320 "%" PRId64 " + virtual "
2321 "%" PRId64 " + virtual and previously indirect "
2322 "%" PRId64 " + stil indirect "
2323 "%" PRId64 " + still indirect polymorphic "
2324 "%" PRId64 "\n", inlined_cnt,
2325 inlined_speculative, inlined_speculative_ply,
2326 inlined_indir_cnt, inlined_virt_cnt, inlined_virt_indir_cnt,
2327 noninlined_cnt, noninlined_indir_cnt, noninlined_virt_cnt,
2328 noninlined_virt_indir_cnt, indirect_cnt, indirect_poly_cnt);
2329 fprintf (dump_file,
2330 "Removed speculations %" PRId64 "\n",
2331 spec_rem);
2333 dump_overall_stats ();
2334 fprintf (dump_file, "\nWhy inlining failed?\n");
2335 for (i = 0; i < CIF_N_REASONS; i++)
2336 if (reason[i][2])
2337 fprintf (dump_file, "%-50s: %8i calls, %8i freq, %" PRId64" count\n",
2338 cgraph_inline_failed_string ((cgraph_inline_failed_t) i),
2339 (int) reason[i][2], (int) reason[i][1], reason[i][0]);
2342 /* Decide on the inlining. We do so in the topological order to avoid
2343 expenses on updating data structures. */
2345 static unsigned int
2346 ipa_inline (void)
2348 struct cgraph_node *node;
2349 int nnodes;
2350 struct cgraph_node **order;
2351 int i;
2352 int cold;
2353 bool remove_functions = false;
2355 if (!optimize)
2356 return 0;
2358 cgraph_freq_base_rec = (sreal) 1 / (sreal) CGRAPH_FREQ_BASE;
2359 percent_rec = (sreal) 1 / (sreal) 100;
2361 order = XCNEWVEC (struct cgraph_node *, symtab->cgraph_count);
2363 if (in_lto_p && optimize)
2364 ipa_update_after_lto_read ();
2366 if (dump_file)
2367 dump_inline_summaries (dump_file);
2369 nnodes = ipa_reverse_postorder (order);
2371 FOR_EACH_FUNCTION (node)
2373 node->aux = 0;
2375 /* Recompute the default reasons for inlining because they may have
2376 changed during merging. */
2377 if (in_lto_p)
2379 for (cgraph_edge *e = node->callees; e; e = e->next_callee)
2381 gcc_assert (e->inline_failed);
2382 initialize_inline_failed (e);
2384 for (cgraph_edge *e = node->indirect_calls; e; e = e->next_callee)
2385 initialize_inline_failed (e);
2389 if (dump_file)
2390 fprintf (dump_file, "\nFlattening functions:\n");
2392 /* In the first pass handle functions to be flattened. Do this with
2393 a priority so none of our later choices will make this impossible. */
2394 for (i = nnodes - 1; i >= 0; i--)
2396 node = order[i];
2398 /* Handle nodes to be flattened.
2399 Ideally when processing callees we stop inlining at the
2400 entry of cycles, possibly cloning that entry point and
2401 try to flatten itself turning it into a self-recursive
2402 function. */
2403 if (lookup_attribute ("flatten",
2404 DECL_ATTRIBUTES (node->decl)) != NULL)
2406 if (dump_file)
2407 fprintf (dump_file,
2408 "Flattening %s\n", node->name ());
2409 flatten_function (node, false);
2412 if (dump_file)
2413 dump_overall_stats ();
2415 inline_small_functions ();
2417 gcc_assert (symtab->state == IPA_SSA);
2418 symtab->state = IPA_SSA_AFTER_INLINING;
2419 /* Do first after-inlining removal. We want to remove all "stale" extern
2420 inline functions and virtual functions so we really know what is called
2421 once. */
2422 symtab->remove_unreachable_nodes (dump_file);
2423 free (order);
2425 /* Inline functions with a property that after inlining into all callers the
2426 code size will shrink because the out-of-line copy is eliminated.
2427 We do this regardless on the callee size as long as function growth limits
2428 are met. */
2429 if (dump_file)
2430 fprintf (dump_file,
2431 "\nDeciding on functions to be inlined into all callers and "
2432 "removing useless speculations:\n");
2434 /* Inlining one function called once has good chance of preventing
2435 inlining other function into the same callee. Ideally we should
2436 work in priority order, but probably inlining hot functions first
2437 is good cut without the extra pain of maintaining the queue.
2439 ??? this is not really fitting the bill perfectly: inlining function
2440 into callee often leads to better optimization of callee due to
2441 increased context for optimization.
2442 For example if main() function calls a function that outputs help
2443 and then function that does the main optmization, we should inline
2444 the second with priority even if both calls are cold by themselves.
2446 We probably want to implement new predicate replacing our use of
2447 maybe_hot_edge interpreted as maybe_hot_edge || callee is known
2448 to be hot. */
2449 for (cold = 0; cold <= 1; cold ++)
2451 FOR_EACH_DEFINED_FUNCTION (node)
2453 struct cgraph_edge *edge, *next;
2454 bool update=false;
2456 for (edge = node->callees; edge; edge = next)
2458 next = edge->next_callee;
2459 if (edge->speculative && !speculation_useful_p (edge, false))
2461 edge->resolve_speculation ();
2462 spec_rem += edge->count;
2463 update = true;
2464 remove_functions = true;
2467 if (update)
2469 struct cgraph_node *where = node->global.inlined_to
2470 ? node->global.inlined_to : node;
2471 reset_edge_caches (where);
2472 inline_update_overall_summary (where);
2474 if (want_inline_function_to_all_callers_p (node, cold))
2476 int num_calls = 0;
2477 node->call_for_symbol_and_aliases (sum_callers, &num_calls,
2478 true);
2479 while (node->call_for_symbol_and_aliases
2480 (inline_to_all_callers, &num_calls, true))
2482 remove_functions = true;
2487 /* Free ipa-prop structures if they are no longer needed. */
2488 if (optimize)
2489 ipa_free_all_structures_after_iinln ();
2491 if (dump_file)
2493 fprintf (dump_file,
2494 "\nInlined %i calls, eliminated %i functions\n\n",
2495 ncalls_inlined, nfunctions_inlined);
2496 dump_inline_stats ();
2499 if (dump_file)
2500 dump_inline_summaries (dump_file);
2501 /* In WPA we use inline summaries for partitioning process. */
2502 if (!flag_wpa)
2503 inline_free_summary ();
2504 return remove_functions ? TODO_remove_functions : 0;
2507 /* Inline always-inline function calls in NODE. */
2509 static bool
2510 inline_always_inline_functions (struct cgraph_node *node)
2512 struct cgraph_edge *e;
2513 bool inlined = false;
2515 for (e = node->callees; e; e = e->next_callee)
2517 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
2518 if (!DECL_DISREGARD_INLINE_LIMITS (callee->decl))
2519 continue;
2521 if (e->recursive_p ())
2523 if (dump_file)
2524 fprintf (dump_file, " Not inlining recursive call to %s.\n",
2525 e->callee->name ());
2526 e->inline_failed = CIF_RECURSIVE_INLINING;
2527 continue;
2530 if (!can_early_inline_edge_p (e))
2532 /* Set inlined to true if the callee is marked "always_inline" but
2533 is not inlinable. This will allow flagging an error later in
2534 expand_call_inline in tree-inline.c. */
2535 if (lookup_attribute ("always_inline",
2536 DECL_ATTRIBUTES (callee->decl)) != NULL)
2537 inlined = true;
2538 continue;
2541 if (dump_file)
2542 fprintf (dump_file, " Inlining %s into %s (always_inline).\n",
2543 xstrdup_for_dump (e->callee->name ()),
2544 xstrdup_for_dump (e->caller->name ()));
2545 inline_call (e, true, NULL, NULL, false);
2546 inlined = true;
2548 if (inlined)
2549 inline_update_overall_summary (node);
2551 return inlined;
2554 /* Decide on the inlining. We do so in the topological order to avoid
2555 expenses on updating data structures. */
2557 static bool
2558 early_inline_small_functions (struct cgraph_node *node)
2560 struct cgraph_edge *e;
2561 bool inlined = false;
2563 for (e = node->callees; e; e = e->next_callee)
2565 struct cgraph_node *callee = e->callee->ultimate_alias_target ();
2566 if (!inline_summaries->get (callee)->inlinable
2567 || !e->inline_failed)
2568 continue;
2570 /* Do not consider functions not declared inline. */
2571 if (!DECL_DECLARED_INLINE_P (callee->decl)
2572 && !opt_for_fn (node->decl, flag_inline_small_functions)
2573 && !opt_for_fn (node->decl, flag_inline_functions))
2574 continue;
2576 if (dump_file)
2577 fprintf (dump_file, "Considering inline candidate %s.\n",
2578 callee->name ());
2580 if (!can_early_inline_edge_p (e))
2581 continue;
2583 if (e->recursive_p ())
2585 if (dump_file)
2586 fprintf (dump_file, " Not inlining: recursive call.\n");
2587 continue;
2590 if (!want_early_inline_function_p (e))
2591 continue;
2593 if (dump_file)
2594 fprintf (dump_file, " Inlining %s into %s.\n",
2595 xstrdup_for_dump (callee->name ()),
2596 xstrdup_for_dump (e->caller->name ()));
2597 inline_call (e, true, NULL, NULL, true);
2598 inlined = true;
2601 return inlined;
2604 unsigned int
2605 early_inliner (function *fun)
2607 struct cgraph_node *node = cgraph_node::get (current_function_decl);
2608 struct cgraph_edge *edge;
2609 unsigned int todo = 0;
2610 int iterations = 0;
2611 bool inlined = false;
2613 if (seen_error ())
2614 return 0;
2616 /* Do nothing if datastructures for ipa-inliner are already computed. This
2617 happens when some pass decides to construct new function and
2618 cgraph_add_new_function calls lowering passes and early optimization on
2619 it. This may confuse ourself when early inliner decide to inline call to
2620 function clone, because function clones don't have parameter list in
2621 ipa-prop matching their signature. */
2622 if (ipa_node_params_sum)
2623 return 0;
2625 if (flag_checking)
2626 node->verify ();
2627 node->remove_all_references ();
2629 /* Rebuild this reference because it dosn't depend on
2630 function's body and it's required to pass cgraph_node
2631 verification. */
2632 if (node->instrumented_version
2633 && !node->instrumentation_clone)
2634 node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
2636 /* Even when not optimizing or not inlining inline always-inline
2637 functions. */
2638 inlined = inline_always_inline_functions (node);
2640 if (!optimize
2641 || flag_no_inline
2642 || !flag_early_inlining
2643 /* Never inline regular functions into always-inline functions
2644 during incremental inlining. This sucks as functions calling
2645 always inline functions will get less optimized, but at the
2646 same time inlining of functions calling always inline
2647 function into an always inline function might introduce
2648 cycles of edges to be always inlined in the callgraph.
2650 We might want to be smarter and just avoid this type of inlining. */
2651 || (DECL_DISREGARD_INLINE_LIMITS (node->decl)
2652 && lookup_attribute ("always_inline",
2653 DECL_ATTRIBUTES (node->decl))))
2655 else if (lookup_attribute ("flatten",
2656 DECL_ATTRIBUTES (node->decl)) != NULL)
2658 /* When the function is marked to be flattened, recursively inline
2659 all calls in it. */
2660 if (dump_file)
2661 fprintf (dump_file,
2662 "Flattening %s\n", node->name ());
2663 flatten_function (node, true);
2664 inlined = true;
2666 else
2668 /* If some always_inline functions was inlined, apply the changes.
2669 This way we will not account always inline into growth limits and
2670 moreover we will inline calls from always inlines that we skipped
2671 previously becuase of conditional above. */
2672 if (inlined)
2674 timevar_push (TV_INTEGRATION);
2675 todo |= optimize_inline_calls (current_function_decl);
2676 /* optimize_inline_calls call above might have introduced new
2677 statements that don't have inline parameters computed. */
2678 for (edge = node->callees; edge; edge = edge->next_callee)
2680 if (inline_edge_summary_vec.length () > (unsigned) edge->uid)
2682 struct inline_edge_summary *es = inline_edge_summary (edge);
2683 es->call_stmt_size
2684 = estimate_num_insns (edge->call_stmt, &eni_size_weights);
2685 es->call_stmt_time
2686 = estimate_num_insns (edge->call_stmt, &eni_time_weights);
2689 inline_update_overall_summary (node);
2690 inlined = false;
2691 timevar_pop (TV_INTEGRATION);
2693 /* We iterate incremental inlining to get trivial cases of indirect
2694 inlining. */
2695 while (iterations < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS)
2696 && early_inline_small_functions (node))
2698 timevar_push (TV_INTEGRATION);
2699 todo |= optimize_inline_calls (current_function_decl);
2701 /* Technically we ought to recompute inline parameters so the new
2702 iteration of early inliner works as expected. We however have
2703 values approximately right and thus we only need to update edge
2704 info that might be cleared out for newly discovered edges. */
2705 for (edge = node->callees; edge; edge = edge->next_callee)
2707 /* We have no summary for new bound store calls yet. */
2708 if (inline_edge_summary_vec.length () > (unsigned)edge->uid)
2710 struct inline_edge_summary *es = inline_edge_summary (edge);
2711 es->call_stmt_size
2712 = estimate_num_insns (edge->call_stmt, &eni_size_weights);
2713 es->call_stmt_time
2714 = estimate_num_insns (edge->call_stmt, &eni_time_weights);
2716 if (edge->callee->decl
2717 && !gimple_check_call_matching_types (
2718 edge->call_stmt, edge->callee->decl, false))
2719 edge->call_stmt_cannot_inline_p = true;
2721 if (iterations < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS) - 1)
2722 inline_update_overall_summary (node);
2723 timevar_pop (TV_INTEGRATION);
2724 iterations++;
2725 inlined = false;
2727 if (dump_file)
2728 fprintf (dump_file, "Iterations: %i\n", iterations);
2731 if (inlined)
2733 timevar_push (TV_INTEGRATION);
2734 todo |= optimize_inline_calls (current_function_decl);
2735 timevar_pop (TV_INTEGRATION);
2738 fun->always_inline_functions_inlined = true;
2740 return todo;
2743 /* Do inlining of small functions. Doing so early helps profiling and other
2744 passes to be somewhat more effective and avoids some code duplication in
2745 later real inlining pass for testcases with very many function calls. */
2747 namespace {
2749 const pass_data pass_data_early_inline =
2751 GIMPLE_PASS, /* type */
2752 "einline", /* name */
2753 OPTGROUP_INLINE, /* optinfo_flags */
2754 TV_EARLY_INLINING, /* tv_id */
2755 PROP_ssa, /* properties_required */
2756 0, /* properties_provided */
2757 0, /* properties_destroyed */
2758 0, /* todo_flags_start */
2759 0, /* todo_flags_finish */
2762 class pass_early_inline : public gimple_opt_pass
2764 public:
2765 pass_early_inline (gcc::context *ctxt)
2766 : gimple_opt_pass (pass_data_early_inline, ctxt)
2769 /* opt_pass methods: */
2770 virtual unsigned int execute (function *);
2772 }; // class pass_early_inline
2774 unsigned int
2775 pass_early_inline::execute (function *fun)
2777 return early_inliner (fun);
2780 } // anon namespace
2782 gimple_opt_pass *
2783 make_pass_early_inline (gcc::context *ctxt)
2785 return new pass_early_inline (ctxt);
2788 namespace {
2790 const pass_data pass_data_ipa_inline =
2792 IPA_PASS, /* type */
2793 "inline", /* name */
2794 OPTGROUP_INLINE, /* optinfo_flags */
2795 TV_IPA_INLINING, /* tv_id */
2796 0, /* properties_required */
2797 0, /* properties_provided */
2798 0, /* properties_destroyed */
2799 0, /* todo_flags_start */
2800 ( TODO_dump_symtab ), /* todo_flags_finish */
2803 class pass_ipa_inline : public ipa_opt_pass_d
2805 public:
2806 pass_ipa_inline (gcc::context *ctxt)
2807 : ipa_opt_pass_d (pass_data_ipa_inline, ctxt,
2808 inline_generate_summary, /* generate_summary */
2809 inline_write_summary, /* write_summary */
2810 inline_read_summary, /* read_summary */
2811 NULL, /* write_optimization_summary */
2812 NULL, /* read_optimization_summary */
2813 NULL, /* stmt_fixup */
2814 0, /* function_transform_todo_flags_start */
2815 inline_transform, /* function_transform */
2816 NULL) /* variable_transform */
2819 /* opt_pass methods: */
2820 virtual unsigned int execute (function *) { return ipa_inline (); }
2822 }; // class pass_ipa_inline
2824 } // anon namespace
2826 ipa_opt_pass_d *
2827 make_pass_ipa_inline (gcc::context *ctxt)
2829 return new pass_ipa_inline (ctxt);