2014-02-12 Richard Biener <rguenther@suse.de>
[official-gcc.git] / gcc / ipa-inline.c
blobd304133bfe4745084238b1bc4cd9ab449a3d3a96
1 /* Inlining decision heuristics.
2 Copyright (C) 2003-2014 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 "tm.h"
96 #include "tree.h"
97 #include "trans-mem.h"
98 #include "calls.h"
99 #include "tree-inline.h"
100 #include "langhooks.h"
101 #include "flags.h"
102 #include "diagnostic.h"
103 #include "gimple-pretty-print.h"
104 #include "params.h"
105 #include "fibheap.h"
106 #include "intl.h"
107 #include "tree-pass.h"
108 #include "coverage.h"
109 #include "rtl.h"
110 #include "bitmap.h"
111 #include "basic-block.h"
112 #include "tree-ssa-alias.h"
113 #include "internal-fn.h"
114 #include "gimple-expr.h"
115 #include "is-a.h"
116 #include "gimple.h"
117 #include "gimple-ssa.h"
118 #include "ipa-prop.h"
119 #include "except.h"
120 #include "target.h"
121 #include "ipa-inline.h"
122 #include "ipa-utils.h"
123 #include "sreal.h"
124 #include "cilk.h"
126 /* Statistics we collect about inlining algorithm. */
127 static int overall_size;
128 static gcov_type max_count;
129 static sreal max_count_real, max_relbenefit_real, half_int_min_real;
131 /* Return false when inlining edge E would lead to violating
132 limits on function unit growth or stack usage growth.
134 The relative function body growth limit is present generally
135 to avoid problems with non-linear behavior of the compiler.
136 To allow inlining huge functions into tiny wrapper, the limit
137 is always based on the bigger of the two functions considered.
139 For stack growth limits we always base the growth in stack usage
140 of the callers. We want to prevent applications from segfaulting
141 on stack overflow when functions with huge stack frames gets
142 inlined. */
144 static bool
145 caller_growth_limits (struct cgraph_edge *e)
147 struct cgraph_node *to = e->caller;
148 struct cgraph_node *what = cgraph_function_or_thunk_node (e->callee, NULL);
149 int newsize;
150 int limit = 0;
151 HOST_WIDE_INT stack_size_limit = 0, inlined_stack;
152 struct inline_summary *info, *what_info, *outer_info = inline_summary (to);
154 /* Look for function e->caller is inlined to. While doing
155 so work out the largest function body on the way. As
156 described above, we want to base our function growth
157 limits based on that. Not on the self size of the
158 outer function, not on the self size of inline code
159 we immediately inline to. This is the most relaxed
160 interpretation of the rule "do not grow large functions
161 too much in order to prevent compiler from exploding". */
162 while (true)
164 info = inline_summary (to);
165 if (limit < info->self_size)
166 limit = info->self_size;
167 if (stack_size_limit < info->estimated_self_stack_size)
168 stack_size_limit = info->estimated_self_stack_size;
169 if (to->global.inlined_to)
170 to = to->callers->caller;
171 else
172 break;
175 what_info = inline_summary (what);
177 if (limit < what_info->self_size)
178 limit = what_info->self_size;
180 limit += limit * PARAM_VALUE (PARAM_LARGE_FUNCTION_GROWTH) / 100;
182 /* Check the size after inlining against the function limits. But allow
183 the function to shrink if it went over the limits by forced inlining. */
184 newsize = estimate_size_after_inlining (to, e);
185 if (newsize >= info->size
186 && newsize > PARAM_VALUE (PARAM_LARGE_FUNCTION_INSNS)
187 && newsize > limit)
189 e->inline_failed = CIF_LARGE_FUNCTION_GROWTH_LIMIT;
190 return false;
193 if (!what_info->estimated_stack_size)
194 return true;
196 /* FIXME: Stack size limit often prevents inlining in Fortran programs
197 due to large i/o datastructures used by the Fortran front-end.
198 We ought to ignore this limit when we know that the edge is executed
199 on every invocation of the caller (i.e. its call statement dominates
200 exit block). We do not track this information, yet. */
201 stack_size_limit += ((gcov_type)stack_size_limit
202 * PARAM_VALUE (PARAM_STACK_FRAME_GROWTH) / 100);
204 inlined_stack = (outer_info->stack_frame_offset
205 + outer_info->estimated_self_stack_size
206 + what_info->estimated_stack_size);
207 /* Check new stack consumption with stack consumption at the place
208 stack is used. */
209 if (inlined_stack > stack_size_limit
210 /* If function already has large stack usage from sibling
211 inline call, we can inline, too.
212 This bit overoptimistically assume that we are good at stack
213 packing. */
214 && inlined_stack > info->estimated_stack_size
215 && inlined_stack > PARAM_VALUE (PARAM_LARGE_STACK_FRAME))
217 e->inline_failed = CIF_LARGE_STACK_FRAME_GROWTH_LIMIT;
218 return false;
220 return true;
223 /* Dump info about why inlining has failed. */
225 static void
226 report_inline_failed_reason (struct cgraph_edge *e)
228 if (dump_file)
230 fprintf (dump_file, " not inlinable: %s/%i -> %s/%i, %s\n",
231 xstrdup (e->caller->name ()), e->caller->order,
232 xstrdup (e->callee->name ()), e->callee->order,
233 cgraph_inline_failed_string (e->inline_failed));
237 /* Decide whether sanitizer-related attributes allow inlining. */
239 static bool
240 sanitize_attrs_match_for_inline_p (const_tree caller, const_tree callee)
242 /* Don't care if sanitizer is disabled */
243 if (!(flag_sanitize & SANITIZE_ADDRESS))
244 return true;
246 if (!caller || !callee)
247 return true;
249 return !!lookup_attribute ("no_sanitize_address",
250 DECL_ATTRIBUTES (caller)) ==
251 !!lookup_attribute ("no_sanitize_address",
252 DECL_ATTRIBUTES (callee));
255 /* Decide if we can inline the edge and possibly update
256 inline_failed reason.
257 We check whether inlining is possible at all and whether
258 caller growth limits allow doing so.
260 if REPORT is true, output reason to the dump file.
262 if DISREGARD_LIMITS is true, ignore size limits.*/
264 static bool
265 can_inline_edge_p (struct cgraph_edge *e, bool report,
266 bool disregard_limits = false)
268 bool inlinable = true;
269 enum availability avail;
270 struct cgraph_node *callee
271 = cgraph_function_or_thunk_node (e->callee, &avail);
272 tree caller_tree = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (e->caller->decl);
273 tree callee_tree
274 = callee ? DECL_FUNCTION_SPECIFIC_OPTIMIZATION (callee->decl) : NULL;
275 struct function *caller_cfun = DECL_STRUCT_FUNCTION (e->caller->decl);
276 struct function *callee_cfun
277 = callee ? DECL_STRUCT_FUNCTION (callee->decl) : NULL;
279 if (!caller_cfun && e->caller->clone_of)
280 caller_cfun = DECL_STRUCT_FUNCTION (e->caller->clone_of->decl);
282 if (!callee_cfun && callee && callee->clone_of)
283 callee_cfun = DECL_STRUCT_FUNCTION (callee->clone_of->decl);
285 gcc_assert (e->inline_failed);
287 if (!callee || !callee->definition)
289 e->inline_failed = CIF_BODY_NOT_AVAILABLE;
290 inlinable = false;
292 else if (callee->calls_comdat_local)
294 e->inline_failed = CIF_USES_COMDAT_LOCAL;
295 inlinable = false;
297 else if (!inline_summary (callee)->inlinable
298 || (caller_cfun && fn_contains_cilk_spawn_p (caller_cfun)))
300 e->inline_failed = CIF_FUNCTION_NOT_INLINABLE;
301 inlinable = false;
303 else if (avail <= AVAIL_OVERWRITABLE)
305 e->inline_failed = CIF_OVERWRITABLE;
306 inlinable = false;
308 else if (e->call_stmt_cannot_inline_p)
310 if (e->inline_failed != CIF_FUNCTION_NOT_OPTIMIZED)
311 e->inline_failed = CIF_MISMATCHED_ARGUMENTS;
312 inlinable = false;
314 /* Don't inline if the functions have different EH personalities. */
315 else if (DECL_FUNCTION_PERSONALITY (e->caller->decl)
316 && DECL_FUNCTION_PERSONALITY (callee->decl)
317 && (DECL_FUNCTION_PERSONALITY (e->caller->decl)
318 != DECL_FUNCTION_PERSONALITY (callee->decl)))
320 e->inline_failed = CIF_EH_PERSONALITY;
321 inlinable = false;
323 /* TM pure functions should not be inlined into non-TM_pure
324 functions. */
325 else if (is_tm_pure (callee->decl)
326 && !is_tm_pure (e->caller->decl))
328 e->inline_failed = CIF_UNSPECIFIED;
329 inlinable = false;
331 /* Don't inline if the callee can throw non-call exceptions but the
332 caller cannot.
333 FIXME: this is obviously wrong for LTO where STRUCT_FUNCTION is missing.
334 Move the flag into cgraph node or mirror it in the inline summary. */
335 else if (callee_cfun && callee_cfun->can_throw_non_call_exceptions
336 && !(caller_cfun && caller_cfun->can_throw_non_call_exceptions))
338 e->inline_failed = CIF_NON_CALL_EXCEPTIONS;
339 inlinable = false;
341 /* Check compatibility of target optimization options. */
342 else if (!targetm.target_option.can_inline_p (e->caller->decl,
343 callee->decl))
345 e->inline_failed = CIF_TARGET_OPTION_MISMATCH;
346 inlinable = false;
348 /* Don't inline a function with mismatched sanitization attributes. */
349 else if (!sanitize_attrs_match_for_inline_p (e->caller->decl, callee->decl))
351 e->inline_failed = CIF_ATTRIBUTE_MISMATCH;
352 inlinable = false;
354 /* Check if caller growth allows the inlining. */
355 else if (!DECL_DISREGARD_INLINE_LIMITS (callee->decl)
356 && !disregard_limits
357 && !lookup_attribute ("flatten",
358 DECL_ATTRIBUTES
359 (e->caller->global.inlined_to
360 ? e->caller->global.inlined_to->decl
361 : e->caller->decl))
362 && !caller_growth_limits (e))
363 inlinable = false;
364 /* Don't inline a function with a higher optimization level than the
365 caller. FIXME: this is really just tip of iceberg of handling
366 optimization attribute. */
367 else if (caller_tree != callee_tree)
369 struct cl_optimization *caller_opt
370 = TREE_OPTIMIZATION ((caller_tree)
371 ? caller_tree
372 : optimization_default_node);
374 struct cl_optimization *callee_opt
375 = TREE_OPTIMIZATION ((callee_tree)
376 ? callee_tree
377 : optimization_default_node);
379 if (((caller_opt->x_optimize > callee_opt->x_optimize)
380 || (caller_opt->x_optimize_size != callee_opt->x_optimize_size))
381 /* gcc.dg/pr43564.c. Look at forced inline even in -O0. */
382 && !DECL_DISREGARD_INLINE_LIMITS (e->callee->decl))
384 e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
385 inlinable = false;
389 if (!inlinable && report)
390 report_inline_failed_reason (e);
391 return inlinable;
395 /* Return true if the edge E is inlinable during early inlining. */
397 static bool
398 can_early_inline_edge_p (struct cgraph_edge *e)
400 struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee,
401 NULL);
402 /* Early inliner might get called at WPA stage when IPA pass adds new
403 function. In this case we can not really do any of early inlining
404 because function bodies are missing. */
405 if (!gimple_has_body_p (callee->decl))
407 e->inline_failed = CIF_BODY_NOT_AVAILABLE;
408 return false;
410 /* In early inliner some of callees may not be in SSA form yet
411 (i.e. the callgraph is cyclic and we did not process
412 the callee by early inliner, yet). We don't have CIF code for this
413 case; later we will re-do the decision in the real inliner. */
414 if (!gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->caller->decl))
415 || !gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->decl)))
417 if (dump_file)
418 fprintf (dump_file, " edge not inlinable: not in SSA form\n");
419 return false;
421 if (!can_inline_edge_p (e, true))
422 return false;
423 return true;
427 /* Return number of calls in N. Ignore cheap builtins. */
429 static int
430 num_calls (struct cgraph_node *n)
432 struct cgraph_edge *e;
433 int num = 0;
435 for (e = n->callees; e; e = e->next_callee)
436 if (!is_inexpensive_builtin (e->callee->decl))
437 num++;
438 return num;
442 /* Return true if we are interested in inlining small function. */
444 static bool
445 want_early_inline_function_p (struct cgraph_edge *e)
447 bool want_inline = true;
448 struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL);
450 if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
452 else if (!DECL_DECLARED_INLINE_P (callee->decl)
453 && !flag_inline_small_functions)
455 e->inline_failed = CIF_FUNCTION_NOT_INLINE_CANDIDATE;
456 report_inline_failed_reason (e);
457 want_inline = false;
459 else
461 int growth = estimate_edge_growth (e);
462 int n;
464 if (growth <= 0)
466 else if (!cgraph_maybe_hot_edge_p (e)
467 && growth > 0)
469 if (dump_file)
470 fprintf (dump_file, " will not early inline: %s/%i->%s/%i, "
471 "call is cold and code would grow by %i\n",
472 xstrdup (e->caller->name ()),
473 e->caller->order,
474 xstrdup (callee->name ()), callee->order,
475 growth);
476 want_inline = false;
478 else if (growth > PARAM_VALUE (PARAM_EARLY_INLINING_INSNS))
480 if (dump_file)
481 fprintf (dump_file, " will not early inline: %s/%i->%s/%i, "
482 "growth %i exceeds --param early-inlining-insns\n",
483 xstrdup (e->caller->name ()),
484 e->caller->order,
485 xstrdup (callee->name ()), callee->order,
486 growth);
487 want_inline = false;
489 else if ((n = num_calls (callee)) != 0
490 && growth * (n + 1) > PARAM_VALUE (PARAM_EARLY_INLINING_INSNS))
492 if (dump_file)
493 fprintf (dump_file, " will not early inline: %s/%i->%s/%i, "
494 "growth %i exceeds --param early-inlining-insns "
495 "divided by number of calls\n",
496 xstrdup (e->caller->name ()),
497 e->caller->order,
498 xstrdup (callee->name ()), callee->order,
499 growth);
500 want_inline = false;
503 return want_inline;
506 /* Compute time of the edge->caller + edge->callee execution when inlining
507 does not happen. */
509 inline gcov_type
510 compute_uninlined_call_time (struct inline_summary *callee_info,
511 struct cgraph_edge *edge)
513 gcov_type uninlined_call_time =
514 RDIV ((gcov_type)callee_info->time * MAX (edge->frequency, 1),
515 CGRAPH_FREQ_BASE);
516 gcov_type caller_time = inline_summary (edge->caller->global.inlined_to
517 ? edge->caller->global.inlined_to
518 : edge->caller)->time;
519 return uninlined_call_time + caller_time;
522 /* Same as compute_uinlined_call_time but compute time when inlining
523 does happen. */
525 inline gcov_type
526 compute_inlined_call_time (struct cgraph_edge *edge,
527 int edge_time)
529 gcov_type caller_time = inline_summary (edge->caller->global.inlined_to
530 ? edge->caller->global.inlined_to
531 : edge->caller)->time;
532 gcov_type time = (caller_time
533 + RDIV (((gcov_type) edge_time
534 - inline_edge_summary (edge)->call_stmt_time)
535 * MAX (edge->frequency, 1), CGRAPH_FREQ_BASE));
536 /* Possible one roundoff error, but watch for overflows. */
537 gcc_checking_assert (time >= INT_MIN / 2);
538 if (time < 0)
539 time = 0;
540 return time;
543 /* Return true if the speedup for inlining E is bigger than
544 PARAM_MAX_INLINE_MIN_SPEEDUP. */
546 static bool
547 big_speedup_p (struct cgraph_edge *e)
549 gcov_type time = compute_uninlined_call_time (inline_summary (e->callee),
551 gcov_type inlined_time = compute_inlined_call_time (e,
552 estimate_edge_time (e));
553 if (time - inlined_time
554 > RDIV (time * PARAM_VALUE (PARAM_INLINE_MIN_SPEEDUP), 100))
555 return true;
556 return false;
559 /* Return true if we are interested in inlining small function.
560 When REPORT is true, report reason to dump file. */
562 static bool
563 want_inline_small_function_p (struct cgraph_edge *e, bool report)
565 bool want_inline = true;
566 struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL);
568 if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
570 else if (!DECL_DECLARED_INLINE_P (callee->decl)
571 && !flag_inline_small_functions)
573 e->inline_failed = CIF_FUNCTION_NOT_INLINE_CANDIDATE;
574 want_inline = false;
576 else
578 int growth = estimate_edge_growth (e);
579 inline_hints hints = estimate_edge_hints (e);
580 bool big_speedup = big_speedup_p (e);
582 if (growth <= 0)
584 /* Apply MAX_INLINE_INSNS_SINGLE limit. Do not do so when
585 hints suggests that inlining given function is very profitable. */
586 else if (DECL_DECLARED_INLINE_P (callee->decl)
587 && growth >= MAX_INLINE_INSNS_SINGLE
588 && !big_speedup
589 && !(hints & (INLINE_HINT_indirect_call
590 | INLINE_HINT_loop_iterations
591 | INLINE_HINT_array_index
592 | INLINE_HINT_loop_stride)))
594 e->inline_failed = CIF_MAX_INLINE_INSNS_SINGLE_LIMIT;
595 want_inline = false;
597 /* Before giving up based on fact that caller size will grow, allow
598 functions that are called few times and eliminating the offline
599 copy will lead to overall code size reduction.
600 Not all of these will be handled by subsequent inlining of functions
601 called once: in particular weak functions are not handled or funcitons
602 that inline to multiple calls but a lot of bodies is optimized out.
603 Finally we want to inline earlier to allow inlining of callbacks.
605 This is slightly wrong on aggressive side: it is entirely possible
606 that function is called many times with a context where inlining
607 reduces code size and few times with a context where inlining increase
608 code size. Resoluting growth estimate will be negative even if it
609 would make more sense to keep offline copy and do not inline into the
610 call sites that makes the code size grow.
612 When badness orders the calls in a way that code reducing calls come
613 first, this situation is not a problem at all: after inlining all
614 "good" calls, we will realize that keeping the function around is
615 better. */
616 else if (growth <= MAX_INLINE_INSNS_SINGLE
617 /* Unlike for functions called once, we play unsafe with
618 COMDATs. We can allow that since we know functions
619 in consideration are small (and thus risk is small) and
620 moreover grow estimates already accounts that COMDAT
621 functions may or may not disappear when eliminated from
622 current unit. With good probability making aggressive
623 choice in all units is going to make overall program
624 smaller.
626 Consequently we ask cgraph_can_remove_if_no_direct_calls_p
627 instead of
628 cgraph_will_be_removed_from_program_if_no_direct_calls */
629 && !DECL_EXTERNAL (callee->decl)
630 && cgraph_can_remove_if_no_direct_calls_p (callee)
631 && estimate_growth (callee) <= 0)
633 else if (!DECL_DECLARED_INLINE_P (callee->decl)
634 && !flag_inline_functions)
636 e->inline_failed = CIF_NOT_DECLARED_INLINED;
637 want_inline = false;
639 /* Apply MAX_INLINE_INSNS_AUTO limit for functions not declared inline
640 Upgrade it to MAX_INLINE_INSNS_SINGLE when hints suggests that
641 inlining given function is very profitable. */
642 else if (!DECL_DECLARED_INLINE_P (callee->decl)
643 && !big_speedup
644 && growth >= ((hints & (INLINE_HINT_indirect_call
645 | INLINE_HINT_loop_iterations
646 | INLINE_HINT_array_index
647 | INLINE_HINT_loop_stride))
648 ? MAX (MAX_INLINE_INSNS_AUTO,
649 MAX_INLINE_INSNS_SINGLE)
650 : MAX_INLINE_INSNS_AUTO))
652 e->inline_failed = CIF_MAX_INLINE_INSNS_AUTO_LIMIT;
653 want_inline = false;
655 /* If call is cold, do not inline when function body would grow. */
656 else if (!cgraph_maybe_hot_edge_p (e))
658 e->inline_failed = CIF_UNLIKELY_CALL;
659 want_inline = false;
662 if (!want_inline && report)
663 report_inline_failed_reason (e);
664 return want_inline;
667 /* EDGE is self recursive edge.
668 We hand two cases - when function A is inlining into itself
669 or when function A is being inlined into another inliner copy of function
670 A within function B.
672 In first case OUTER_NODE points to the toplevel copy of A, while
673 in the second case OUTER_NODE points to the outermost copy of A in B.
675 In both cases we want to be extra selective since
676 inlining the call will just introduce new recursive calls to appear. */
678 static bool
679 want_inline_self_recursive_call_p (struct cgraph_edge *edge,
680 struct cgraph_node *outer_node,
681 bool peeling,
682 int depth)
684 char const *reason = NULL;
685 bool want_inline = true;
686 int caller_freq = CGRAPH_FREQ_BASE;
687 int max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO);
689 if (DECL_DECLARED_INLINE_P (edge->caller->decl))
690 max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH);
692 if (!cgraph_maybe_hot_edge_p (edge))
694 reason = "recursive call is cold";
695 want_inline = false;
697 else if (max_count && !outer_node->count)
699 reason = "not executed in profile";
700 want_inline = false;
702 else if (depth > max_depth)
704 reason = "--param max-inline-recursive-depth exceeded.";
705 want_inline = false;
708 if (outer_node->global.inlined_to)
709 caller_freq = outer_node->callers->frequency;
711 if (!want_inline)
713 /* Inlining of self recursive function into copy of itself within other function
714 is transformation similar to loop peeling.
716 Peeling is profitable if we can inline enough copies to make probability
717 of actual call to the self recursive function very small. Be sure that
718 the probability of recursion is small.
720 We ensure that the frequency of recursing is at most 1 - (1/max_depth).
721 This way the expected number of recision is at most max_depth. */
722 else if (peeling)
724 int max_prob = CGRAPH_FREQ_BASE - ((CGRAPH_FREQ_BASE + max_depth - 1)
725 / max_depth);
726 int i;
727 for (i = 1; i < depth; i++)
728 max_prob = max_prob * max_prob / CGRAPH_FREQ_BASE;
729 if (max_count
730 && (edge->count * CGRAPH_FREQ_BASE / outer_node->count
731 >= max_prob))
733 reason = "profile of recursive call is too large";
734 want_inline = false;
736 if (!max_count
737 && (edge->frequency * CGRAPH_FREQ_BASE / caller_freq
738 >= max_prob))
740 reason = "frequency of recursive call is too large";
741 want_inline = false;
744 /* Recursive inlining, i.e. equivalent of unrolling, is profitable if recursion
745 depth is large. We reduce function call overhead and increase chances that
746 things fit in hardware return predictor.
748 Recursive inlining might however increase cost of stack frame setup
749 actually slowing down functions whose recursion tree is wide rather than
750 deep.
752 Deciding reliably on when to do recursive inlining without profile feedback
753 is tricky. For now we disable recursive inlining when probability of self
754 recursion is low.
756 Recursive inlining of self recursive call within loop also results in large loop
757 depths that generally optimize badly. We may want to throttle down inlining
758 in those cases. In particular this seems to happen in one of libstdc++ rb tree
759 methods. */
760 else
762 if (max_count
763 && (edge->count * 100 / outer_node->count
764 <= PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY)))
766 reason = "profile of recursive call is too small";
767 want_inline = false;
769 else if (!max_count
770 && (edge->frequency * 100 / caller_freq
771 <= PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY)))
773 reason = "frequency of recursive call is too small";
774 want_inline = false;
777 if (!want_inline && dump_file)
778 fprintf (dump_file, " not inlining recursively: %s\n", reason);
779 return want_inline;
782 /* Return true when NODE has uninlinable caller;
783 set HAS_HOT_CALL if it has hot call.
784 Worker for cgraph_for_node_and_aliases. */
786 static bool
787 check_callers (struct cgraph_node *node, void *has_hot_call)
789 struct cgraph_edge *e;
790 for (e = node->callers; e; e = e->next_caller)
792 if (!can_inline_edge_p (e, true))
793 return true;
794 if (!(*(bool *)has_hot_call) && cgraph_maybe_hot_edge_p (e))
795 *(bool *)has_hot_call = true;
797 return false;
800 /* If NODE has a caller, return true. */
802 static bool
803 has_caller_p (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
805 if (node->callers)
806 return true;
807 return false;
810 /* Decide if inlining NODE would reduce unit size by eliminating
811 the offline copy of function.
812 When COLD is true the cold calls are considered, too. */
814 static bool
815 want_inline_function_to_all_callers_p (struct cgraph_node *node, bool cold)
817 struct cgraph_node *function = cgraph_function_or_thunk_node (node, NULL);
818 bool has_hot_call = false;
820 /* Does it have callers? */
821 if (!cgraph_for_node_and_aliases (node, has_caller_p, NULL, true))
822 return false;
823 /* Already inlined? */
824 if (function->global.inlined_to)
825 return false;
826 if (cgraph_function_or_thunk_node (node, NULL) != node)
827 return false;
828 /* Inlining into all callers would increase size? */
829 if (estimate_growth (node) > 0)
830 return false;
831 /* All inlines must be possible. */
832 if (cgraph_for_node_and_aliases (node, check_callers, &has_hot_call, true))
833 return false;
834 if (!cold && !has_hot_call)
835 return false;
836 return true;
839 #define RELATIVE_TIME_BENEFIT_RANGE (INT_MAX / 64)
841 /* Return relative time improvement for inlining EDGE in range
842 1...RELATIVE_TIME_BENEFIT_RANGE */
844 static inline int
845 relative_time_benefit (struct inline_summary *callee_info,
846 struct cgraph_edge *edge,
847 int edge_time)
849 gcov_type relbenefit;
850 gcov_type uninlined_call_time = compute_uninlined_call_time (callee_info, edge);
851 gcov_type inlined_call_time = compute_inlined_call_time (edge, edge_time);
853 /* Inlining into extern inline function is not a win. */
854 if (DECL_EXTERNAL (edge->caller->global.inlined_to
855 ? edge->caller->global.inlined_to->decl
856 : edge->caller->decl))
857 return 1;
859 /* Watch overflows. */
860 gcc_checking_assert (uninlined_call_time >= 0);
861 gcc_checking_assert (inlined_call_time >= 0);
862 gcc_checking_assert (uninlined_call_time >= inlined_call_time);
864 /* Compute relative time benefit, i.e. how much the call becomes faster.
865 ??? perhaps computing how much the caller+calle together become faster
866 would lead to more realistic results. */
867 if (!uninlined_call_time)
868 uninlined_call_time = 1;
869 relbenefit =
870 RDIV (((gcov_type)uninlined_call_time - inlined_call_time) * RELATIVE_TIME_BENEFIT_RANGE,
871 uninlined_call_time);
872 relbenefit = MIN (relbenefit, RELATIVE_TIME_BENEFIT_RANGE);
873 gcc_checking_assert (relbenefit >= 0);
874 relbenefit = MAX (relbenefit, 1);
875 return relbenefit;
879 /* A cost model driving the inlining heuristics in a way so the edges with
880 smallest badness are inlined first. After each inlining is performed
881 the costs of all caller edges of nodes affected are recomputed so the
882 metrics may accurately depend on values such as number of inlinable callers
883 of the function or function body size. */
885 static int
886 edge_badness (struct cgraph_edge *edge, bool dump)
888 gcov_type badness;
889 int growth, edge_time;
890 struct cgraph_node *callee = cgraph_function_or_thunk_node (edge->callee,
891 NULL);
892 struct inline_summary *callee_info = inline_summary (callee);
893 inline_hints hints;
895 if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
896 return INT_MIN;
898 growth = estimate_edge_growth (edge);
899 edge_time = estimate_edge_time (edge);
900 hints = estimate_edge_hints (edge);
901 gcc_checking_assert (edge_time >= 0);
902 gcc_checking_assert (edge_time <= callee_info->time);
903 gcc_checking_assert (growth <= callee_info->size);
905 if (dump)
907 fprintf (dump_file, " Badness calculation for %s/%i -> %s/%i\n",
908 xstrdup (edge->caller->name ()),
909 edge->caller->order,
910 xstrdup (callee->name ()),
911 edge->callee->order);
912 fprintf (dump_file, " size growth %i, time %i ",
913 growth,
914 edge_time);
915 dump_inline_hints (dump_file, hints);
916 if (big_speedup_p (edge))
917 fprintf (dump_file, " big_speedup");
918 fprintf (dump_file, "\n");
921 /* Always prefer inlining saving code size. */
922 if (growth <= 0)
924 badness = INT_MIN / 2 + growth;
925 if (dump)
926 fprintf (dump_file, " %i: Growth %i <= 0\n", (int) badness,
927 growth);
930 /* When profiling is available, compute badness as:
932 relative_edge_count * relative_time_benefit
933 goodness = -------------------------------------------
934 growth_f_caller
935 badness = -goodness
937 The fraction is upside down, because on edge counts and time beneits
938 the bounds are known. Edge growth is essentially unlimited. */
940 else if (max_count)
942 sreal tmp, relbenefit_real, growth_real;
943 int relbenefit = relative_time_benefit (callee_info, edge, edge_time);
944 /* Capping edge->count to max_count. edge->count can be larger than
945 max_count if an inline adds new edges which increase max_count
946 after max_count is computed. */
947 gcov_type edge_count = edge->count > max_count ? max_count : edge->count;
949 sreal_init (&relbenefit_real, relbenefit, 0);
950 sreal_init (&growth_real, growth, 0);
952 /* relative_edge_count. */
953 sreal_init (&tmp, edge_count, 0);
954 sreal_div (&tmp, &tmp, &max_count_real);
956 /* relative_time_benefit. */
957 sreal_mul (&tmp, &tmp, &relbenefit_real);
958 sreal_div (&tmp, &tmp, &max_relbenefit_real);
960 /* growth_f_caller. */
961 sreal_mul (&tmp, &tmp, &half_int_min_real);
962 sreal_div (&tmp, &tmp, &growth_real);
964 badness = -1 * sreal_to_int (&tmp);
966 if (dump)
968 fprintf (dump_file,
969 " %i (relative %f): profile info. Relative count %f%s"
970 " * Relative benefit %f\n",
971 (int) badness, (double) badness / INT_MIN,
972 (double) edge_count / max_count,
973 edge->count > max_count ? " (capped to max_count)" : "",
974 relbenefit * 100.0 / RELATIVE_TIME_BENEFIT_RANGE);
978 /* When function local profile is available. Compute badness as:
980 relative_time_benefit
981 goodness = ---------------------------------
982 growth_of_caller * overall_growth
984 badness = - goodness
986 compensated by the inline hints.
988 else if (flag_guess_branch_prob)
990 badness = (relative_time_benefit (callee_info, edge, edge_time)
991 * (INT_MIN / 16 / RELATIVE_TIME_BENEFIT_RANGE));
992 badness /= (MIN (65536/2, growth) * MIN (65536/2, MAX (1, callee_info->growth)));
993 gcc_checking_assert (badness <=0 && badness >= INT_MIN / 16);
994 if ((hints & (INLINE_HINT_indirect_call
995 | INLINE_HINT_loop_iterations
996 | INLINE_HINT_array_index
997 | INLINE_HINT_loop_stride))
998 || callee_info->growth <= 0)
999 badness *= 8;
1000 if (hints & (INLINE_HINT_same_scc))
1001 badness /= 16;
1002 else if (hints & (INLINE_HINT_in_scc))
1003 badness /= 8;
1004 else if (hints & (INLINE_HINT_cross_module))
1005 badness /= 2;
1006 gcc_checking_assert (badness <= 0 && badness >= INT_MIN / 2);
1007 if ((hints & INLINE_HINT_declared_inline) && badness >= INT_MIN / 32)
1008 badness *= 16;
1009 if (dump)
1011 fprintf (dump_file,
1012 " %i: guessed profile. frequency %f,"
1013 " benefit %f%%, time w/o inlining %i, time w inlining %i"
1014 " overall growth %i (current) %i (original)\n",
1015 (int) badness, (double)edge->frequency / CGRAPH_FREQ_BASE,
1016 relative_time_benefit (callee_info, edge, edge_time) * 100.0
1017 / RELATIVE_TIME_BENEFIT_RANGE,
1018 (int)compute_uninlined_call_time (callee_info, edge),
1019 (int)compute_inlined_call_time (edge, edge_time),
1020 estimate_growth (callee),
1021 callee_info->growth);
1024 /* When function local profile is not available or it does not give
1025 useful information (ie frequency is zero), base the cost on
1026 loop nest and overall size growth, so we optimize for overall number
1027 of functions fully inlined in program. */
1028 else
1030 int nest = MIN (inline_edge_summary (edge)->loop_depth, 8);
1031 badness = growth * 256;
1033 /* Decrease badness if call is nested. */
1034 if (badness > 0)
1035 badness >>= nest;
1036 else
1038 badness <<= nest;
1040 if (dump)
1041 fprintf (dump_file, " %i: no profile. nest %i\n", (int) badness,
1042 nest);
1045 /* Ensure that we did not overflow in all the fixed point math above. */
1046 gcc_assert (badness >= INT_MIN);
1047 gcc_assert (badness <= INT_MAX - 1);
1048 /* Make recursive inlining happen always after other inlining is done. */
1049 if (cgraph_edge_recursive_p (edge))
1050 return badness + 1;
1051 else
1052 return badness;
1055 /* Recompute badness of EDGE and update its key in HEAP if needed. */
1056 static inline void
1057 update_edge_key (fibheap_t heap, struct cgraph_edge *edge)
1059 int badness = edge_badness (edge, false);
1060 if (edge->aux)
1062 fibnode_t n = (fibnode_t) edge->aux;
1063 gcc_checking_assert (n->data == edge);
1065 /* fibheap_replace_key only decrease the keys.
1066 When we increase the key we do not update heap
1067 and instead re-insert the element once it becomes
1068 a minimum of heap. */
1069 if (badness < n->key)
1071 if (dump_file && (dump_flags & TDF_DETAILS))
1073 fprintf (dump_file,
1074 " decreasing badness %s/%i -> %s/%i, %i to %i\n",
1075 xstrdup (edge->caller->name ()),
1076 edge->caller->order,
1077 xstrdup (edge->callee->name ()),
1078 edge->callee->order,
1079 (int)n->key,
1080 badness);
1082 fibheap_replace_key (heap, n, badness);
1083 gcc_checking_assert (n->key == badness);
1086 else
1088 if (dump_file && (dump_flags & TDF_DETAILS))
1090 fprintf (dump_file,
1091 " enqueuing call %s/%i -> %s/%i, badness %i\n",
1092 xstrdup (edge->caller->name ()),
1093 edge->caller->order,
1094 xstrdup (edge->callee->name ()),
1095 edge->callee->order,
1096 badness);
1098 edge->aux = fibheap_insert (heap, badness, edge);
1103 /* NODE was inlined.
1104 All caller edges needs to be resetted because
1105 size estimates change. Similarly callees needs reset
1106 because better context may be known. */
1108 static void
1109 reset_edge_caches (struct cgraph_node *node)
1111 struct cgraph_edge *edge;
1112 struct cgraph_edge *e = node->callees;
1113 struct cgraph_node *where = node;
1114 int i;
1115 struct ipa_ref *ref;
1117 if (where->global.inlined_to)
1118 where = where->global.inlined_to;
1120 /* WHERE body size has changed, the cached growth is invalid. */
1121 reset_node_growth_cache (where);
1123 for (edge = where->callers; edge; edge = edge->next_caller)
1124 if (edge->inline_failed)
1125 reset_edge_growth_cache (edge);
1126 for (i = 0; ipa_ref_list_referring_iterate (&where->ref_list,
1127 i, ref); i++)
1128 if (ref->use == IPA_REF_ALIAS)
1129 reset_edge_caches (ipa_ref_referring_node (ref));
1131 if (!e)
1132 return;
1134 while (true)
1135 if (!e->inline_failed && e->callee->callees)
1136 e = e->callee->callees;
1137 else
1139 if (e->inline_failed)
1140 reset_edge_growth_cache (e);
1141 if (e->next_callee)
1142 e = e->next_callee;
1143 else
1147 if (e->caller == node)
1148 return;
1149 e = e->caller->callers;
1151 while (!e->next_callee);
1152 e = e->next_callee;
1157 /* Recompute HEAP nodes for each of caller of NODE.
1158 UPDATED_NODES track nodes we already visited, to avoid redundant work.
1159 When CHECK_INLINABLITY_FOR is set, re-check for specified edge that
1160 it is inlinable. Otherwise check all edges. */
1162 static void
1163 update_caller_keys (fibheap_t heap, struct cgraph_node *node,
1164 bitmap updated_nodes,
1165 struct cgraph_edge *check_inlinablity_for)
1167 struct cgraph_edge *edge;
1168 int i;
1169 struct ipa_ref *ref;
1171 if ((!node->alias && !inline_summary (node)->inlinable)
1172 || node->global.inlined_to)
1173 return;
1174 if (!bitmap_set_bit (updated_nodes, node->uid))
1175 return;
1177 for (i = 0; ipa_ref_list_referring_iterate (&node->ref_list,
1178 i, ref); i++)
1179 if (ref->use == IPA_REF_ALIAS)
1181 struct cgraph_node *alias = ipa_ref_referring_node (ref);
1182 update_caller_keys (heap, alias, updated_nodes, check_inlinablity_for);
1185 for (edge = node->callers; edge; edge = edge->next_caller)
1186 if (edge->inline_failed)
1188 if (!check_inlinablity_for
1189 || check_inlinablity_for == edge)
1191 if (can_inline_edge_p (edge, false)
1192 && want_inline_small_function_p (edge, false))
1193 update_edge_key (heap, edge);
1194 else if (edge->aux)
1196 report_inline_failed_reason (edge);
1197 fibheap_delete_node (heap, (fibnode_t) edge->aux);
1198 edge->aux = NULL;
1201 else if (edge->aux)
1202 update_edge_key (heap, edge);
1206 /* Recompute HEAP nodes for each uninlined call in NODE.
1207 This is used when we know that edge badnesses are going only to increase
1208 (we introduced new call site) and thus all we need is to insert newly
1209 created edges into heap. */
1211 static void
1212 update_callee_keys (fibheap_t heap, struct cgraph_node *node,
1213 bitmap updated_nodes)
1215 struct cgraph_edge *e = node->callees;
1217 if (!e)
1218 return;
1219 while (true)
1220 if (!e->inline_failed && e->callee->callees)
1221 e = e->callee->callees;
1222 else
1224 enum availability avail;
1225 struct cgraph_node *callee;
1226 /* We do not reset callee growth cache here. Since we added a new call,
1227 growth chould have just increased and consequentely badness metric
1228 don't need updating. */
1229 if (e->inline_failed
1230 && (callee = cgraph_function_or_thunk_node (e->callee, &avail))
1231 && inline_summary (callee)->inlinable
1232 && avail >= AVAIL_AVAILABLE
1233 && !bitmap_bit_p (updated_nodes, callee->uid))
1235 if (can_inline_edge_p (e, false)
1236 && want_inline_small_function_p (e, false))
1237 update_edge_key (heap, e);
1238 else if (e->aux)
1240 report_inline_failed_reason (e);
1241 fibheap_delete_node (heap, (fibnode_t) e->aux);
1242 e->aux = NULL;
1245 if (e->next_callee)
1246 e = e->next_callee;
1247 else
1251 if (e->caller == node)
1252 return;
1253 e = e->caller->callers;
1255 while (!e->next_callee);
1256 e = e->next_callee;
1261 /* Enqueue all recursive calls from NODE into priority queue depending on
1262 how likely we want to recursively inline the call. */
1264 static void
1265 lookup_recursive_calls (struct cgraph_node *node, struct cgraph_node *where,
1266 fibheap_t heap)
1268 struct cgraph_edge *e;
1269 enum availability avail;
1271 for (e = where->callees; e; e = e->next_callee)
1272 if (e->callee == node
1273 || (cgraph_function_or_thunk_node (e->callee, &avail) == node
1274 && avail > AVAIL_OVERWRITABLE))
1276 /* When profile feedback is available, prioritize by expected number
1277 of calls. */
1278 fibheap_insert (heap,
1279 !max_count ? -e->frequency
1280 : -(e->count / ((max_count + (1<<24) - 1) / (1<<24))),
1283 for (e = where->callees; e; e = e->next_callee)
1284 if (!e->inline_failed)
1285 lookup_recursive_calls (node, e->callee, heap);
1288 /* Decide on recursive inlining: in the case function has recursive calls,
1289 inline until body size reaches given argument. If any new indirect edges
1290 are discovered in the process, add them to *NEW_EDGES, unless NEW_EDGES
1291 is NULL. */
1293 static bool
1294 recursive_inlining (struct cgraph_edge *edge,
1295 vec<cgraph_edge_p> *new_edges)
1297 int limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO);
1298 fibheap_t heap;
1299 struct cgraph_node *node;
1300 struct cgraph_edge *e;
1301 struct cgraph_node *master_clone = NULL, *next;
1302 int depth = 0;
1303 int n = 0;
1305 node = edge->caller;
1306 if (node->global.inlined_to)
1307 node = node->global.inlined_to;
1309 if (DECL_DECLARED_INLINE_P (node->decl))
1310 limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE);
1312 /* Make sure that function is small enough to be considered for inlining. */
1313 if (estimate_size_after_inlining (node, edge) >= limit)
1314 return false;
1315 heap = fibheap_new ();
1316 lookup_recursive_calls (node, node, heap);
1317 if (fibheap_empty (heap))
1319 fibheap_delete (heap);
1320 return false;
1323 if (dump_file)
1324 fprintf (dump_file,
1325 " Performing recursive inlining on %s\n",
1326 node->name ());
1328 /* Do the inlining and update list of recursive call during process. */
1329 while (!fibheap_empty (heap))
1331 struct cgraph_edge *curr
1332 = (struct cgraph_edge *) fibheap_extract_min (heap);
1333 struct cgraph_node *cnode, *dest = curr->callee;
1335 if (!can_inline_edge_p (curr, true))
1336 continue;
1338 /* MASTER_CLONE is produced in the case we already started modified
1339 the function. Be sure to redirect edge to the original body before
1340 estimating growths otherwise we will be seeing growths after inlining
1341 the already modified body. */
1342 if (master_clone)
1344 cgraph_redirect_edge_callee (curr, master_clone);
1345 reset_edge_growth_cache (curr);
1348 if (estimate_size_after_inlining (node, curr) > limit)
1350 cgraph_redirect_edge_callee (curr, dest);
1351 reset_edge_growth_cache (curr);
1352 break;
1355 depth = 1;
1356 for (cnode = curr->caller;
1357 cnode->global.inlined_to; cnode = cnode->callers->caller)
1358 if (node->decl
1359 == cgraph_function_or_thunk_node (curr->callee, NULL)->decl)
1360 depth++;
1362 if (!want_inline_self_recursive_call_p (curr, node, false, depth))
1364 cgraph_redirect_edge_callee (curr, dest);
1365 reset_edge_growth_cache (curr);
1366 continue;
1369 if (dump_file)
1371 fprintf (dump_file,
1372 " Inlining call of depth %i", depth);
1373 if (node->count)
1375 fprintf (dump_file, " called approx. %.2f times per call",
1376 (double)curr->count / node->count);
1378 fprintf (dump_file, "\n");
1380 if (!master_clone)
1382 /* We need original clone to copy around. */
1383 master_clone = cgraph_clone_node (node, node->decl,
1384 node->count, CGRAPH_FREQ_BASE,
1385 false, vNULL, true, NULL);
1386 for (e = master_clone->callees; e; e = e->next_callee)
1387 if (!e->inline_failed)
1388 clone_inlined_nodes (e, true, false, NULL);
1389 cgraph_redirect_edge_callee (curr, master_clone);
1390 reset_edge_growth_cache (curr);
1393 inline_call (curr, false, new_edges, &overall_size, true);
1394 lookup_recursive_calls (node, curr->callee, heap);
1395 n++;
1398 if (!fibheap_empty (heap) && dump_file)
1399 fprintf (dump_file, " Recursive inlining growth limit met.\n");
1400 fibheap_delete (heap);
1402 if (!master_clone)
1403 return false;
1405 if (dump_file)
1406 fprintf (dump_file,
1407 "\n Inlined %i times, "
1408 "body grown from size %i to %i, time %i to %i\n", n,
1409 inline_summary (master_clone)->size, inline_summary (node)->size,
1410 inline_summary (master_clone)->time, inline_summary (node)->time);
1412 /* Remove master clone we used for inlining. We rely that clones inlined
1413 into master clone gets queued just before master clone so we don't
1414 need recursion. */
1415 for (node = cgraph_first_function (); node != master_clone;
1416 node = next)
1418 next = cgraph_next_function (node);
1419 if (node->global.inlined_to == master_clone)
1420 cgraph_remove_node (node);
1422 cgraph_remove_node (master_clone);
1423 return true;
1427 /* Given whole compilation unit estimate of INSNS, compute how large we can
1428 allow the unit to grow. */
1430 static int
1431 compute_max_insns (int insns)
1433 int max_insns = insns;
1434 if (max_insns < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS))
1435 max_insns = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS);
1437 return ((HOST_WIDEST_INT) max_insns
1438 * (100 + PARAM_VALUE (PARAM_INLINE_UNIT_GROWTH)) / 100);
1442 /* Compute badness of all edges in NEW_EDGES and add them to the HEAP. */
1444 static void
1445 add_new_edges_to_heap (fibheap_t heap, vec<cgraph_edge_p> new_edges)
1447 while (new_edges.length () > 0)
1449 struct cgraph_edge *edge = new_edges.pop ();
1451 gcc_assert (!edge->aux);
1452 if (edge->inline_failed
1453 && can_inline_edge_p (edge, true)
1454 && want_inline_small_function_p (edge, true))
1455 edge->aux = fibheap_insert (heap, edge_badness (edge, false), edge);
1459 /* Remove EDGE from the fibheap. */
1461 static void
1462 heap_edge_removal_hook (struct cgraph_edge *e, void *data)
1464 if (e->callee)
1465 reset_node_growth_cache (e->callee);
1466 if (e->aux)
1468 fibheap_delete_node ((fibheap_t)data, (fibnode_t)e->aux);
1469 e->aux = NULL;
1473 /* Return true if speculation of edge E seems useful.
1474 If ANTICIPATE_INLINING is true, be conservative and hope that E
1475 may get inlined. */
1477 bool
1478 speculation_useful_p (struct cgraph_edge *e, bool anticipate_inlining)
1480 enum availability avail;
1481 struct cgraph_node *target = cgraph_function_or_thunk_node (e->callee, &avail);
1482 struct cgraph_edge *direct, *indirect;
1483 struct ipa_ref *ref;
1485 gcc_assert (e->speculative && !e->indirect_unknown_callee);
1487 if (!cgraph_maybe_hot_edge_p (e))
1488 return false;
1490 /* See if IP optimizations found something potentially useful about the
1491 function. For now we look only for CONST/PURE flags. Almost everything
1492 else we propagate is useless. */
1493 if (avail >= AVAIL_AVAILABLE)
1495 int ecf_flags = flags_from_decl_or_type (target->decl);
1496 if (ecf_flags & ECF_CONST)
1498 cgraph_speculative_call_info (e, direct, indirect, ref);
1499 if (!(indirect->indirect_info->ecf_flags & ECF_CONST))
1500 return true;
1502 else if (ecf_flags & ECF_PURE)
1504 cgraph_speculative_call_info (e, direct, indirect, ref);
1505 if (!(indirect->indirect_info->ecf_flags & ECF_PURE))
1506 return true;
1509 /* If we did not managed to inline the function nor redirect
1510 to an ipa-cp clone (that are seen by having local flag set),
1511 it is probably pointless to inline it unless hardware is missing
1512 indirect call predictor. */
1513 if (!anticipate_inlining && e->inline_failed && !target->local.local)
1514 return false;
1515 /* For overwritable targets there is not much to do. */
1516 if (e->inline_failed && !can_inline_edge_p (e, false, true))
1517 return false;
1518 /* OK, speculation seems interesting. */
1519 return true;
1522 /* We know that EDGE is not going to be inlined.
1523 See if we can remove speculation. */
1525 static void
1526 resolve_noninline_speculation (fibheap_t edge_heap, struct cgraph_edge *edge)
1528 if (edge->speculative && !speculation_useful_p (edge, false))
1530 struct cgraph_node *node = edge->caller;
1531 struct cgraph_node *where = node->global.inlined_to
1532 ? node->global.inlined_to : node;
1533 bitmap updated_nodes = BITMAP_ALLOC (NULL);
1535 cgraph_resolve_speculation (edge, NULL);
1536 reset_edge_caches (where);
1537 inline_update_overall_summary (where);
1538 update_caller_keys (edge_heap, where,
1539 updated_nodes, NULL);
1540 update_callee_keys (edge_heap, where,
1541 updated_nodes);
1542 BITMAP_FREE (updated_nodes);
1546 /* We use greedy algorithm for inlining of small functions:
1547 All inline candidates are put into prioritized heap ordered in
1548 increasing badness.
1550 The inlining of small functions is bounded by unit growth parameters. */
1552 static void
1553 inline_small_functions (void)
1555 struct cgraph_node *node;
1556 struct cgraph_edge *edge;
1557 fibheap_t edge_heap = fibheap_new ();
1558 bitmap updated_nodes = BITMAP_ALLOC (NULL);
1559 int min_size, max_size;
1560 auto_vec<cgraph_edge_p> new_indirect_edges;
1561 int initial_size = 0;
1562 struct cgraph_node **order = XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);
1563 struct cgraph_edge_hook_list *edge_removal_hook_holder;
1565 if (flag_indirect_inlining)
1566 new_indirect_edges.create (8);
1568 edge_removal_hook_holder
1569 = cgraph_add_edge_removal_hook (&heap_edge_removal_hook, edge_heap);
1571 /* Compute overall unit size and other global parameters used by badness
1572 metrics. */
1574 max_count = 0;
1575 ipa_reduced_postorder (order, true, true, NULL);
1576 free (order);
1578 FOR_EACH_DEFINED_FUNCTION (node)
1579 if (!node->global.inlined_to)
1581 if (cgraph_function_with_gimple_body_p (node)
1582 || node->thunk.thunk_p)
1584 struct inline_summary *info = inline_summary (node);
1585 struct ipa_dfs_info *dfs = (struct ipa_dfs_info *) node->aux;
1587 if (!DECL_EXTERNAL (node->decl))
1588 initial_size += info->size;
1589 info->growth = estimate_growth (node);
1590 if (dfs && dfs->next_cycle)
1592 struct cgraph_node *n2;
1593 int id = dfs->scc_no + 1;
1594 for (n2 = node; n2;
1595 n2 = ((struct ipa_dfs_info *) node->aux)->next_cycle)
1597 struct inline_summary *info2 = inline_summary (n2);
1598 if (info2->scc_no)
1599 break;
1600 info2->scc_no = id;
1605 for (edge = node->callers; edge; edge = edge->next_caller)
1606 if (max_count < edge->count)
1607 max_count = edge->count;
1609 sreal_init (&max_count_real, max_count, 0);
1610 sreal_init (&max_relbenefit_real, RELATIVE_TIME_BENEFIT_RANGE, 0);
1611 sreal_init (&half_int_min_real, INT_MAX / 2, 0);
1612 ipa_free_postorder_info ();
1613 initialize_growth_caches ();
1615 if (dump_file)
1616 fprintf (dump_file,
1617 "\nDeciding on inlining of small functions. Starting with size %i.\n",
1618 initial_size);
1620 overall_size = initial_size;
1621 max_size = compute_max_insns (overall_size);
1622 min_size = overall_size;
1624 /* Populate the heap with all edges we might inline. */
1626 FOR_EACH_DEFINED_FUNCTION (node)
1628 bool update = false;
1629 struct cgraph_edge *next;
1631 if (dump_file)
1632 fprintf (dump_file, "Enqueueing calls in %s/%i.\n",
1633 node->name (), node->order);
1635 for (edge = node->callees; edge; edge = next)
1637 next = edge->next_callee;
1638 if (edge->inline_failed
1639 && !edge->aux
1640 && can_inline_edge_p (edge, true)
1641 && want_inline_small_function_p (edge, true)
1642 && edge->inline_failed)
1644 gcc_assert (!edge->aux);
1645 update_edge_key (edge_heap, edge);
1647 if (edge->speculative && !speculation_useful_p (edge, edge->aux != NULL))
1649 cgraph_resolve_speculation (edge, NULL);
1650 update = true;
1653 if (update)
1655 struct cgraph_node *where = node->global.inlined_to
1656 ? node->global.inlined_to : node;
1657 inline_update_overall_summary (where);
1658 reset_node_growth_cache (where);
1659 reset_edge_caches (where);
1660 update_caller_keys (edge_heap, where,
1661 updated_nodes, NULL);
1662 bitmap_clear (updated_nodes);
1666 gcc_assert (in_lto_p
1667 || !max_count
1668 || (profile_info && flag_branch_probabilities));
1670 while (!fibheap_empty (edge_heap))
1672 int old_size = overall_size;
1673 struct cgraph_node *where, *callee;
1674 int badness = fibheap_min_key (edge_heap);
1675 int current_badness;
1676 int cached_badness;
1677 int growth;
1679 edge = (struct cgraph_edge *) fibheap_extract_min (edge_heap);
1680 gcc_assert (edge->aux);
1681 edge->aux = NULL;
1682 if (!edge->inline_failed)
1683 continue;
1685 /* Be sure that caches are maintained consistent.
1686 We can not make this ENABLE_CHECKING only because it cause different
1687 updates of the fibheap queue. */
1688 cached_badness = edge_badness (edge, false);
1689 reset_edge_growth_cache (edge);
1690 reset_node_growth_cache (edge->callee);
1692 /* When updating the edge costs, we only decrease badness in the keys.
1693 Increases of badness are handled lazilly; when we see key with out
1694 of date value on it, we re-insert it now. */
1695 current_badness = edge_badness (edge, false);
1696 gcc_assert (cached_badness == current_badness);
1697 gcc_assert (current_badness >= badness);
1698 if (current_badness != badness)
1700 edge->aux = fibheap_insert (edge_heap, current_badness, edge);
1701 continue;
1704 if (!can_inline_edge_p (edge, true))
1706 resolve_noninline_speculation (edge_heap, edge);
1707 continue;
1710 callee = cgraph_function_or_thunk_node (edge->callee, NULL);
1711 growth = estimate_edge_growth (edge);
1712 if (dump_file)
1714 fprintf (dump_file,
1715 "\nConsidering %s/%i with %i size\n",
1716 callee->name (), callee->order,
1717 inline_summary (callee)->size);
1718 fprintf (dump_file,
1719 " to be inlined into %s/%i in %s:%i\n"
1720 " Estimated growth after inlined into all is %+i insns.\n"
1721 " Estimated badness is %i, frequency %.2f.\n",
1722 edge->caller->name (), edge->caller->order,
1723 flag_wpa ? "unknown"
1724 : gimple_filename ((const_gimple) edge->call_stmt),
1725 flag_wpa ? -1
1726 : gimple_lineno ((const_gimple) edge->call_stmt),
1727 estimate_growth (callee),
1728 badness,
1729 edge->frequency / (double)CGRAPH_FREQ_BASE);
1730 if (edge->count)
1731 fprintf (dump_file," Called "HOST_WIDEST_INT_PRINT_DEC"x\n",
1732 edge->count);
1733 if (dump_flags & TDF_DETAILS)
1734 edge_badness (edge, true);
1737 if (overall_size + growth > max_size
1738 && !DECL_DISREGARD_INLINE_LIMITS (callee->decl))
1740 edge->inline_failed = CIF_INLINE_UNIT_GROWTH_LIMIT;
1741 report_inline_failed_reason (edge);
1742 resolve_noninline_speculation (edge_heap, edge);
1743 continue;
1746 if (!want_inline_small_function_p (edge, true))
1748 resolve_noninline_speculation (edge_heap, edge);
1749 continue;
1752 /* Heuristics for inlining small functions work poorly for
1753 recursive calls where we do effects similar to loop unrolling.
1754 When inlining such edge seems profitable, leave decision on
1755 specific inliner. */
1756 if (cgraph_edge_recursive_p (edge))
1758 where = edge->caller;
1759 if (where->global.inlined_to)
1760 where = where->global.inlined_to;
1761 if (!recursive_inlining (edge,
1762 flag_indirect_inlining
1763 ? &new_indirect_edges : NULL))
1765 edge->inline_failed = CIF_RECURSIVE_INLINING;
1766 resolve_noninline_speculation (edge_heap, edge);
1767 continue;
1769 reset_edge_caches (where);
1770 /* Recursive inliner inlines all recursive calls of the function
1771 at once. Consequently we need to update all callee keys. */
1772 if (flag_indirect_inlining)
1773 add_new_edges_to_heap (edge_heap, new_indirect_edges);
1774 update_callee_keys (edge_heap, where, updated_nodes);
1775 bitmap_clear (updated_nodes);
1777 else
1779 struct cgraph_node *outer_node = NULL;
1780 int depth = 0;
1782 /* Consider the case where self recursive function A is inlined
1783 into B. This is desired optimization in some cases, since it
1784 leads to effect similar of loop peeling and we might completely
1785 optimize out the recursive call. However we must be extra
1786 selective. */
1788 where = edge->caller;
1789 while (where->global.inlined_to)
1791 if (where->decl == callee->decl)
1792 outer_node = where, depth++;
1793 where = where->callers->caller;
1795 if (outer_node
1796 && !want_inline_self_recursive_call_p (edge, outer_node,
1797 true, depth))
1799 edge->inline_failed
1800 = (DECL_DISREGARD_INLINE_LIMITS (edge->callee->decl)
1801 ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED);
1802 resolve_noninline_speculation (edge_heap, edge);
1803 continue;
1805 else if (depth && dump_file)
1806 fprintf (dump_file, " Peeling recursion with depth %i\n", depth);
1808 gcc_checking_assert (!callee->global.inlined_to);
1809 inline_call (edge, true, &new_indirect_edges, &overall_size, true);
1810 if (flag_indirect_inlining)
1811 add_new_edges_to_heap (edge_heap, new_indirect_edges);
1813 reset_edge_caches (edge->callee);
1814 reset_node_growth_cache (callee);
1816 update_callee_keys (edge_heap, where, updated_nodes);
1818 where = edge->caller;
1819 if (where->global.inlined_to)
1820 where = where->global.inlined_to;
1822 /* Our profitability metric can depend on local properties
1823 such as number of inlinable calls and size of the function body.
1824 After inlining these properties might change for the function we
1825 inlined into (since it's body size changed) and for the functions
1826 called by function we inlined (since number of it inlinable callers
1827 might change). */
1828 update_caller_keys (edge_heap, where, updated_nodes, NULL);
1829 bitmap_clear (updated_nodes);
1831 if (dump_file)
1833 fprintf (dump_file,
1834 " Inlined into %s which now has time %i and size %i,"
1835 "net change of %+i.\n",
1836 edge->caller->name (),
1837 inline_summary (edge->caller)->time,
1838 inline_summary (edge->caller)->size,
1839 overall_size - old_size);
1841 if (min_size > overall_size)
1843 min_size = overall_size;
1844 max_size = compute_max_insns (min_size);
1846 if (dump_file)
1847 fprintf (dump_file, "New minimal size reached: %i\n", min_size);
1851 free_growth_caches ();
1852 fibheap_delete (edge_heap);
1853 if (dump_file)
1854 fprintf (dump_file,
1855 "Unit growth for small function inlining: %i->%i (%i%%)\n",
1856 initial_size, overall_size,
1857 initial_size ? overall_size * 100 / (initial_size) - 100: 0);
1858 BITMAP_FREE (updated_nodes);
1859 cgraph_remove_edge_removal_hook (edge_removal_hook_holder);
1862 /* Flatten NODE. Performed both during early inlining and
1863 at IPA inlining time. */
1865 static void
1866 flatten_function (struct cgraph_node *node, bool early)
1868 struct cgraph_edge *e;
1870 /* We shouldn't be called recursively when we are being processed. */
1871 gcc_assert (node->aux == NULL);
1873 node->aux = (void *) node;
1875 for (e = node->callees; e; e = e->next_callee)
1877 struct cgraph_node *orig_callee;
1878 struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL);
1880 /* We've hit cycle? It is time to give up. */
1881 if (callee->aux)
1883 if (dump_file)
1884 fprintf (dump_file,
1885 "Not inlining %s into %s to avoid cycle.\n",
1886 xstrdup (callee->name ()),
1887 xstrdup (e->caller->name ()));
1888 e->inline_failed = CIF_RECURSIVE_INLINING;
1889 continue;
1892 /* When the edge is already inlined, we just need to recurse into
1893 it in order to fully flatten the leaves. */
1894 if (!e->inline_failed)
1896 flatten_function (callee, early);
1897 continue;
1900 /* Flatten attribute needs to be processed during late inlining. For
1901 extra code quality we however do flattening during early optimization,
1902 too. */
1903 if (!early
1904 ? !can_inline_edge_p (e, true)
1905 : !can_early_inline_edge_p (e))
1906 continue;
1908 if (cgraph_edge_recursive_p (e))
1910 if (dump_file)
1911 fprintf (dump_file, "Not inlining: recursive call.\n");
1912 continue;
1915 if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node->decl))
1916 != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee->decl)))
1918 if (dump_file)
1919 fprintf (dump_file, "Not inlining: SSA form does not match.\n");
1920 continue;
1923 /* Inline the edge and flatten the inline clone. Avoid
1924 recursing through the original node if the node was cloned. */
1925 if (dump_file)
1926 fprintf (dump_file, " Inlining %s into %s.\n",
1927 xstrdup (callee->name ()),
1928 xstrdup (e->caller->name ()));
1929 orig_callee = callee;
1930 inline_call (e, true, NULL, NULL, false);
1931 if (e->callee != orig_callee)
1932 orig_callee->aux = (void *) node;
1933 flatten_function (e->callee, early);
1934 if (e->callee != orig_callee)
1935 orig_callee->aux = NULL;
1938 node->aux = NULL;
1939 if (!node->global.inlined_to)
1940 inline_update_overall_summary (node);
1943 /* Count number of callers of NODE and store it into DATA (that
1944 points to int. Worker for cgraph_for_node_and_aliases. */
1946 static bool
1947 sum_callers (struct cgraph_node *node, void *data)
1949 struct cgraph_edge *e;
1950 int *num_calls = (int *)data;
1952 for (e = node->callers; e; e = e->next_caller)
1953 (*num_calls)++;
1954 return false;
1957 /* Inline NODE to all callers. Worker for cgraph_for_node_and_aliases.
1958 DATA points to number of calls originally found so we avoid infinite
1959 recursion. */
1961 static bool
1962 inline_to_all_callers (struct cgraph_node *node, void *data)
1964 int *num_calls = (int *)data;
1965 while (node->callers && !node->global.inlined_to)
1967 struct cgraph_node *caller = node->callers->caller;
1969 if (dump_file)
1971 fprintf (dump_file,
1972 "\nInlining %s size %i.\n",
1973 node->name (),
1974 inline_summary (node)->size);
1975 fprintf (dump_file,
1976 " Called once from %s %i insns.\n",
1977 node->callers->caller->name (),
1978 inline_summary (node->callers->caller)->size);
1981 inline_call (node->callers, true, NULL, NULL, true);
1982 if (dump_file)
1983 fprintf (dump_file,
1984 " Inlined into %s which now has %i size\n",
1985 caller->name (),
1986 inline_summary (caller)->size);
1987 if (!(*num_calls)--)
1989 if (dump_file)
1990 fprintf (dump_file, "New calls found; giving up.\n");
1991 return true;
1994 return false;
1997 /* Decide on the inlining. We do so in the topological order to avoid
1998 expenses on updating data structures. */
2000 static unsigned int
2001 ipa_inline (void)
2003 struct cgraph_node *node;
2004 int nnodes;
2005 struct cgraph_node **order;
2006 int i;
2007 int cold;
2008 bool remove_functions = false;
2010 if (!optimize)
2011 return 0;
2013 order = XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);
2015 if (in_lto_p && optimize)
2016 ipa_update_after_lto_read ();
2018 if (dump_file)
2019 dump_inline_summaries (dump_file);
2021 nnodes = ipa_reverse_postorder (order);
2023 FOR_EACH_FUNCTION (node)
2024 node->aux = 0;
2026 if (dump_file)
2027 fprintf (dump_file, "\nFlattening functions:\n");
2029 /* In the first pass handle functions to be flattened. Do this with
2030 a priority so none of our later choices will make this impossible. */
2031 for (i = nnodes - 1; i >= 0; i--)
2033 node = order[i];
2035 /* Handle nodes to be flattened.
2036 Ideally when processing callees we stop inlining at the
2037 entry of cycles, possibly cloning that entry point and
2038 try to flatten itself turning it into a self-recursive
2039 function. */
2040 if (lookup_attribute ("flatten",
2041 DECL_ATTRIBUTES (node->decl)) != NULL)
2043 if (dump_file)
2044 fprintf (dump_file,
2045 "Flattening %s\n", node->name ());
2046 flatten_function (node, false);
2050 inline_small_functions ();
2052 /* Do first after-inlining removal. We want to remove all "stale" extern inline
2053 functions and virtual functions so we really know what is called once. */
2054 symtab_remove_unreachable_nodes (false, dump_file);
2055 free (order);
2057 /* Inline functions with a property that after inlining into all callers the
2058 code size will shrink because the out-of-line copy is eliminated.
2059 We do this regardless on the callee size as long as function growth limits
2060 are met. */
2061 if (dump_file)
2062 fprintf (dump_file,
2063 "\nDeciding on functions to be inlined into all callers and removing useless speculations:\n");
2065 /* Inlining one function called once has good chance of preventing
2066 inlining other function into the same callee. Ideally we should
2067 work in priority order, but probably inlining hot functions first
2068 is good cut without the extra pain of maintaining the queue.
2070 ??? this is not really fitting the bill perfectly: inlining function
2071 into callee often leads to better optimization of callee due to
2072 increased context for optimization.
2073 For example if main() function calls a function that outputs help
2074 and then function that does the main optmization, we should inline
2075 the second with priority even if both calls are cold by themselves.
2077 We probably want to implement new predicate replacing our use of
2078 maybe_hot_edge interpreted as maybe_hot_edge || callee is known
2079 to be hot. */
2080 for (cold = 0; cold <= 1; cold ++)
2082 FOR_EACH_DEFINED_FUNCTION (node)
2084 struct cgraph_edge *edge, *next;
2085 bool update=false;
2087 for (edge = node->callees; edge; edge = next)
2089 next = edge->next_callee;
2090 if (edge->speculative && !speculation_useful_p (edge, false))
2092 cgraph_resolve_speculation (edge, NULL);
2093 update = true;
2094 remove_functions = true;
2097 if (update)
2099 struct cgraph_node *where = node->global.inlined_to
2100 ? node->global.inlined_to : node;
2101 reset_node_growth_cache (where);
2102 reset_edge_caches (where);
2103 inline_update_overall_summary (where);
2105 if (flag_inline_functions_called_once
2106 && want_inline_function_to_all_callers_p (node, cold))
2108 int num_calls = 0;
2109 cgraph_for_node_and_aliases (node, sum_callers,
2110 &num_calls, true);
2111 cgraph_for_node_and_aliases (node, inline_to_all_callers,
2112 &num_calls, true);
2113 remove_functions = true;
2118 /* Free ipa-prop structures if they are no longer needed. */
2119 if (optimize)
2120 ipa_free_all_structures_after_iinln ();
2122 if (dump_file)
2123 fprintf (dump_file,
2124 "\nInlined %i calls, eliminated %i functions\n\n",
2125 ncalls_inlined, nfunctions_inlined);
2127 if (dump_file)
2128 dump_inline_summaries (dump_file);
2129 /* In WPA we use inline summaries for partitioning process. */
2130 if (!flag_wpa)
2131 inline_free_summary ();
2132 return remove_functions ? TODO_remove_functions : 0;
2135 /* Inline always-inline function calls in NODE. */
2137 static bool
2138 inline_always_inline_functions (struct cgraph_node *node)
2140 struct cgraph_edge *e;
2141 bool inlined = false;
2143 for (e = node->callees; e; e = e->next_callee)
2145 struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL);
2146 if (!DECL_DISREGARD_INLINE_LIMITS (callee->decl))
2147 continue;
2149 if (cgraph_edge_recursive_p (e))
2151 if (dump_file)
2152 fprintf (dump_file, " Not inlining recursive call to %s.\n",
2153 e->callee->name ());
2154 e->inline_failed = CIF_RECURSIVE_INLINING;
2155 continue;
2158 if (!can_early_inline_edge_p (e))
2160 /* Set inlined to true if the callee is marked "always_inline" but
2161 is not inlinable. This will allow flagging an error later in
2162 expand_call_inline in tree-inline.c. */
2163 if (lookup_attribute ("always_inline",
2164 DECL_ATTRIBUTES (callee->decl)) != NULL)
2165 inlined = true;
2166 continue;
2169 if (dump_file)
2170 fprintf (dump_file, " Inlining %s into %s (always_inline).\n",
2171 xstrdup (e->callee->name ()),
2172 xstrdup (e->caller->name ()));
2173 inline_call (e, true, NULL, NULL, false);
2174 inlined = true;
2176 if (inlined)
2177 inline_update_overall_summary (node);
2179 return inlined;
2182 /* Decide on the inlining. We do so in the topological order to avoid
2183 expenses on updating data structures. */
2185 static bool
2186 early_inline_small_functions (struct cgraph_node *node)
2188 struct cgraph_edge *e;
2189 bool inlined = false;
2191 for (e = node->callees; e; e = e->next_callee)
2193 struct cgraph_node *callee = cgraph_function_or_thunk_node (e->callee, NULL);
2194 if (!inline_summary (callee)->inlinable
2195 || !e->inline_failed)
2196 continue;
2198 /* Do not consider functions not declared inline. */
2199 if (!DECL_DECLARED_INLINE_P (callee->decl)
2200 && !flag_inline_small_functions
2201 && !flag_inline_functions)
2202 continue;
2204 if (dump_file)
2205 fprintf (dump_file, "Considering inline candidate %s.\n",
2206 callee->name ());
2208 if (!can_early_inline_edge_p (e))
2209 continue;
2211 if (cgraph_edge_recursive_p (e))
2213 if (dump_file)
2214 fprintf (dump_file, " Not inlining: recursive call.\n");
2215 continue;
2218 if (!want_early_inline_function_p (e))
2219 continue;
2221 if (dump_file)
2222 fprintf (dump_file, " Inlining %s into %s.\n",
2223 xstrdup (callee->name ()),
2224 xstrdup (e->caller->name ()));
2225 inline_call (e, true, NULL, NULL, true);
2226 inlined = true;
2229 return inlined;
2232 /* Do inlining of small functions. Doing so early helps profiling and other
2233 passes to be somewhat more effective and avoids some code duplication in
2234 later real inlining pass for testcases with very many function calls. */
2235 static unsigned int
2236 early_inliner (void)
2238 struct cgraph_node *node = cgraph_get_node (current_function_decl);
2239 struct cgraph_edge *edge;
2240 unsigned int todo = 0;
2241 int iterations = 0;
2242 bool inlined = false;
2244 if (seen_error ())
2245 return 0;
2247 /* Do nothing if datastructures for ipa-inliner are already computed. This
2248 happens when some pass decides to construct new function and
2249 cgraph_add_new_function calls lowering passes and early optimization on
2250 it. This may confuse ourself when early inliner decide to inline call to
2251 function clone, because function clones don't have parameter list in
2252 ipa-prop matching their signature. */
2253 if (ipa_node_params_vector.exists ())
2254 return 0;
2256 #ifdef ENABLE_CHECKING
2257 verify_cgraph_node (node);
2258 #endif
2259 ipa_remove_all_references (&node->ref_list);
2261 /* Even when not optimizing or not inlining inline always-inline
2262 functions. */
2263 inlined = inline_always_inline_functions (node);
2265 if (!optimize
2266 || flag_no_inline
2267 || !flag_early_inlining
2268 /* Never inline regular functions into always-inline functions
2269 during incremental inlining. This sucks as functions calling
2270 always inline functions will get less optimized, but at the
2271 same time inlining of functions calling always inline
2272 function into an always inline function might introduce
2273 cycles of edges to be always inlined in the callgraph.
2275 We might want to be smarter and just avoid this type of inlining. */
2276 || DECL_DISREGARD_INLINE_LIMITS (node->decl))
2278 else if (lookup_attribute ("flatten",
2279 DECL_ATTRIBUTES (node->decl)) != NULL)
2281 /* When the function is marked to be flattened, recursively inline
2282 all calls in it. */
2283 if (dump_file)
2284 fprintf (dump_file,
2285 "Flattening %s\n", node->name ());
2286 flatten_function (node, true);
2287 inlined = true;
2289 else
2291 /* We iterate incremental inlining to get trivial cases of indirect
2292 inlining. */
2293 while (iterations < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS)
2294 && early_inline_small_functions (node))
2296 timevar_push (TV_INTEGRATION);
2297 todo |= optimize_inline_calls (current_function_decl);
2299 /* Technically we ought to recompute inline parameters so the new
2300 iteration of early inliner works as expected. We however have
2301 values approximately right and thus we only need to update edge
2302 info that might be cleared out for newly discovered edges. */
2303 for (edge = node->callees; edge; edge = edge->next_callee)
2305 struct inline_edge_summary *es = inline_edge_summary (edge);
2306 es->call_stmt_size
2307 = estimate_num_insns (edge->call_stmt, &eni_size_weights);
2308 es->call_stmt_time
2309 = estimate_num_insns (edge->call_stmt, &eni_time_weights);
2310 if (edge->callee->decl
2311 && !gimple_check_call_matching_types (
2312 edge->call_stmt, edge->callee->decl, false))
2313 edge->call_stmt_cannot_inline_p = true;
2315 timevar_pop (TV_INTEGRATION);
2316 iterations++;
2317 inlined = false;
2319 if (dump_file)
2320 fprintf (dump_file, "Iterations: %i\n", iterations);
2323 if (inlined)
2325 timevar_push (TV_INTEGRATION);
2326 todo |= optimize_inline_calls (current_function_decl);
2327 timevar_pop (TV_INTEGRATION);
2330 cfun->always_inline_functions_inlined = true;
2332 return todo;
2335 namespace {
2337 const pass_data pass_data_early_inline =
2339 GIMPLE_PASS, /* type */
2340 "einline", /* name */
2341 OPTGROUP_INLINE, /* optinfo_flags */
2342 false, /* has_gate */
2343 true, /* has_execute */
2344 TV_EARLY_INLINING, /* tv_id */
2345 PROP_ssa, /* properties_required */
2346 0, /* properties_provided */
2347 0, /* properties_destroyed */
2348 0, /* todo_flags_start */
2349 0, /* todo_flags_finish */
2352 class pass_early_inline : public gimple_opt_pass
2354 public:
2355 pass_early_inline (gcc::context *ctxt)
2356 : gimple_opt_pass (pass_data_early_inline, ctxt)
2359 /* opt_pass methods: */
2360 unsigned int execute () { return early_inliner (); }
2362 }; // class pass_early_inline
2364 } // anon namespace
2366 gimple_opt_pass *
2367 make_pass_early_inline (gcc::context *ctxt)
2369 return new pass_early_inline (ctxt);
2372 namespace {
2374 const pass_data pass_data_ipa_inline =
2376 IPA_PASS, /* type */
2377 "inline", /* name */
2378 OPTGROUP_INLINE, /* optinfo_flags */
2379 false, /* has_gate */
2380 true, /* has_execute */
2381 TV_IPA_INLINING, /* tv_id */
2382 0, /* properties_required */
2383 0, /* properties_provided */
2384 0, /* properties_destroyed */
2385 TODO_remove_functions, /* todo_flags_start */
2386 ( TODO_dump_symtab ), /* todo_flags_finish */
2389 class pass_ipa_inline : public ipa_opt_pass_d
2391 public:
2392 pass_ipa_inline (gcc::context *ctxt)
2393 : ipa_opt_pass_d (pass_data_ipa_inline, ctxt,
2394 inline_generate_summary, /* generate_summary */
2395 inline_write_summary, /* write_summary */
2396 inline_read_summary, /* read_summary */
2397 NULL, /* write_optimization_summary */
2398 NULL, /* read_optimization_summary */
2399 NULL, /* stmt_fixup */
2400 0, /* function_transform_todo_flags_start */
2401 inline_transform, /* function_transform */
2402 NULL) /* variable_transform */
2405 /* opt_pass methods: */
2406 unsigned int execute () { return ipa_inline (); }
2408 }; // class pass_ipa_inline
2410 } // anon namespace
2412 ipa_opt_pass_d *
2413 make_pass_ipa_inline (gcc::context *ctxt)
2415 return new pass_ipa_inline (ctxt);