1 /* Inlining decision heuristics.
2 Copyright (C) 2003, 2004, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
4 Contributed by Jan Hubicka
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Inlining decision heuristics
24 The implementation of inliner is organized as follows:
26 inlining heuristics limits
28 can_inline_edge_p allow to check that particular inlining is allowed
29 by the limits specified by user (allowed function growth, growth and so
32 Functions are inlined when it is obvious the result is profitable (such
33 as functions called once or when inlining reduce code size).
34 In addition to that we perform inlining of small functions and recursive
39 The inliner itself is split into two passes:
43 Simple local inlining pass inlining callees into current function.
44 This pass makes no use of whole unit analysis and thus it can do only
45 very simple decisions based on local properties.
47 The strength of the pass is that it is run in topological order
48 (reverse postorder) on the callgraph. Functions are converted into SSA
49 form just before this pass and optimized subsequently. As a result, the
50 callees of the function seen by the early inliner was already optimized
51 and results of early inlining adds a lot of optimization opportunities
52 for the local optimization.
54 The pass handle the obvious inlining decisions within the compilation
55 unit - inlining auto inline functions, inlining for size and
58 main strength of the pass is the ability to eliminate abstraction
59 penalty in C++ code (via combination of inlining and early
60 optimization) and thus improve quality of analysis done by real IPA
63 Because of lack of whole unit knowledge, the pass can not really make
64 good code size/performance tradeoffs. It however does very simple
65 speculative inlining allowing code size to grow by
66 EARLY_INLINING_INSNS when callee is leaf function. In this case the
67 optimizations performed later are very likely to eliminate the cost.
71 This is the real inliner able to handle inlining with whole program
72 knowledge. It performs following steps:
74 1) inlining of small functions. This is implemented by greedy
75 algorithm ordering all inlinable cgraph edges by their badness and
76 inlining them in this order as long as inline limits allows doing so.
78 This heuristics is not very good on inlining recursive calls. Recursive
79 calls can be inlined with results similar to loop unrolling. To do so,
80 special purpose recursive inliner is executed on function when
81 recursive edge is met as viable candidate.
83 2) Unreachable functions are removed from callgraph. Inlining leads
84 to devirtualization and other modification of callgraph so functions
85 may become unreachable during the process. Also functions declared as
86 extern inline or virtual functions are removed, since after inlining
87 we no longer need the offline bodies.
89 3) Functions called once and not exported from the unit are inlined.
90 This should almost always lead to reduction of code size by eliminating
91 the need for offline copy of the function. */
95 #include "coretypes.h"
98 #include "tree-inline.h"
99 #include "langhooks.h"
102 #include "diagnostic.h"
103 #include "gimple-pretty-print.h"
108 #include "tree-pass.h"
109 #include "coverage.h"
112 #include "tree-flow.h"
113 #include "ipa-prop.h"
116 #include "ipa-inline.h"
117 #include "ipa-utils.h"
119 /* Statistics we collect about inlining algorithm. */
120 static int overall_size
;
121 static gcov_type max_count
;
123 /* Return false when inlining edge E would lead to violating
124 limits on function unit growth or stack usage growth.
126 The relative function body growth limit is present generally
127 to avoid problems with non-linear behavior of the compiler.
128 To allow inlining huge functions into tiny wrapper, the limit
129 is always based on the bigger of the two functions considered.
131 For stack growth limits we always base the growth in stack usage
132 of the callers. We want to prevent applications from segfaulting
133 on stack overflow when functions with huge stack frames gets
137 caller_growth_limits (struct cgraph_edge
*e
)
139 struct cgraph_node
*to
= e
->caller
;
140 struct cgraph_node
*what
= cgraph_function_or_thunk_node (e
->callee
, NULL
);
143 HOST_WIDE_INT stack_size_limit
= 0, inlined_stack
;
144 struct inline_summary
*info
, *what_info
, *outer_info
= inline_summary (to
);
146 /* Look for function e->caller is inlined to. While doing
147 so work out the largest function body on the way. As
148 described above, we want to base our function growth
149 limits based on that. Not on the self size of the
150 outer function, not on the self size of inline code
151 we immediately inline to. This is the most relaxed
152 interpretation of the rule "do not grow large functions
153 too much in order to prevent compiler from exploding". */
156 info
= inline_summary (to
);
157 if (limit
< info
->self_size
)
158 limit
= info
->self_size
;
159 if (stack_size_limit
< info
->estimated_self_stack_size
)
160 stack_size_limit
= info
->estimated_self_stack_size
;
161 if (to
->global
.inlined_to
)
162 to
= to
->callers
->caller
;
167 what_info
= inline_summary (what
);
169 if (limit
< what_info
->self_size
)
170 limit
= what_info
->self_size
;
172 limit
+= limit
* PARAM_VALUE (PARAM_LARGE_FUNCTION_GROWTH
) / 100;
174 /* Check the size after inlining against the function limits. But allow
175 the function to shrink if it went over the limits by forced inlining. */
176 newsize
= estimate_size_after_inlining (to
, e
);
177 if (newsize
>= info
->size
178 && newsize
> PARAM_VALUE (PARAM_LARGE_FUNCTION_INSNS
)
181 e
->inline_failed
= CIF_LARGE_FUNCTION_GROWTH_LIMIT
;
185 if (!what_info
->estimated_stack_size
)
188 /* FIXME: Stack size limit often prevents inlining in Fortran programs
189 due to large i/o datastructures used by the Fortran front-end.
190 We ought to ignore this limit when we know that the edge is executed
191 on every invocation of the caller (i.e. its call statement dominates
192 exit block). We do not track this information, yet. */
193 stack_size_limit
+= ((gcov_type
)stack_size_limit
194 * PARAM_VALUE (PARAM_STACK_FRAME_GROWTH
) / 100);
196 inlined_stack
= (outer_info
->stack_frame_offset
197 + outer_info
->estimated_self_stack_size
198 + what_info
->estimated_stack_size
);
199 /* Check new stack consumption with stack consumption at the place
201 if (inlined_stack
> stack_size_limit
202 /* If function already has large stack usage from sibling
203 inline call, we can inline, too.
204 This bit overoptimistically assume that we are good at stack
206 && inlined_stack
> info
->estimated_stack_size
207 && inlined_stack
> PARAM_VALUE (PARAM_LARGE_STACK_FRAME
))
209 e
->inline_failed
= CIF_LARGE_STACK_FRAME_GROWTH_LIMIT
;
215 /* Dump info about why inlining has failed. */
218 report_inline_failed_reason (struct cgraph_edge
*e
)
222 fprintf (dump_file
, " not inlinable: %s/%i -> %s/%i, %s\n",
223 cgraph_node_name (e
->caller
), e
->caller
->uid
,
224 cgraph_node_name (e
->callee
), e
->callee
->uid
,
225 cgraph_inline_failed_string (e
->inline_failed
));
229 /* Decide if we can inline the edge and possibly update
230 inline_failed reason.
231 We check whether inlining is possible at all and whether
232 caller growth limits allow doing so.
234 if REPORT is true, output reason to the dump file. */
237 can_inline_edge_p (struct cgraph_edge
*e
, bool report
)
239 bool inlinable
= true;
240 enum availability avail
;
241 struct cgraph_node
*callee
242 = cgraph_function_or_thunk_node (e
->callee
, &avail
);
243 tree caller_tree
= DECL_FUNCTION_SPECIFIC_OPTIMIZATION (e
->caller
->decl
);
245 = callee
? DECL_FUNCTION_SPECIFIC_OPTIMIZATION (callee
->decl
) : NULL
;
246 struct function
*caller_cfun
= DECL_STRUCT_FUNCTION (e
->caller
->decl
);
247 struct function
*callee_cfun
248 = callee
? DECL_STRUCT_FUNCTION (callee
->decl
) : NULL
;
250 if (!caller_cfun
&& e
->caller
->clone_of
)
251 caller_cfun
= DECL_STRUCT_FUNCTION (e
->caller
->clone_of
->decl
);
253 if (!callee_cfun
&& callee
&& callee
->clone_of
)
254 callee_cfun
= DECL_STRUCT_FUNCTION (callee
->clone_of
->decl
);
256 gcc_assert (e
->inline_failed
);
258 if (!callee
|| !callee
->analyzed
)
260 e
->inline_failed
= CIF_BODY_NOT_AVAILABLE
;
263 else if (!inline_summary (callee
)->inlinable
)
265 e
->inline_failed
= CIF_FUNCTION_NOT_INLINABLE
;
268 else if (avail
<= AVAIL_OVERWRITABLE
)
270 e
->inline_failed
= CIF_OVERWRITABLE
;
273 else if (e
->call_stmt_cannot_inline_p
)
275 e
->inline_failed
= CIF_MISMATCHED_ARGUMENTS
;
278 /* Don't inline if the functions have different EH personalities. */
279 else if (DECL_FUNCTION_PERSONALITY (e
->caller
->decl
)
280 && DECL_FUNCTION_PERSONALITY (callee
->decl
)
281 && (DECL_FUNCTION_PERSONALITY (e
->caller
->decl
)
282 != DECL_FUNCTION_PERSONALITY (callee
->decl
)))
284 e
->inline_failed
= CIF_EH_PERSONALITY
;
287 /* Don't inline if the callee can throw non-call exceptions but the
289 FIXME: this is obviously wrong for LTO where STRUCT_FUNCTION is missing.
290 Move the flag into cgraph node or mirror it in the inline summary. */
291 else if (callee_cfun
&& callee_cfun
->can_throw_non_call_exceptions
292 && !(caller_cfun
&& caller_cfun
->can_throw_non_call_exceptions
))
294 e
->inline_failed
= CIF_NON_CALL_EXCEPTIONS
;
297 /* Check compatibility of target optimization options. */
298 else if (!targetm
.target_option
.can_inline_p (e
->caller
->decl
,
301 e
->inline_failed
= CIF_TARGET_OPTION_MISMATCH
;
304 /* Check if caller growth allows the inlining. */
305 else if (!DECL_DISREGARD_INLINE_LIMITS (callee
->decl
)
306 && !lookup_attribute ("flatten",
308 (e
->caller
->global
.inlined_to
309 ? e
->caller
->global
.inlined_to
->decl
311 && !caller_growth_limits (e
))
313 /* Don't inline a function with a higher optimization level than the
314 caller. FIXME: this is really just tip of iceberg of handling
315 optimization attribute. */
316 else if (caller_tree
!= callee_tree
)
318 struct cl_optimization
*caller_opt
319 = TREE_OPTIMIZATION ((caller_tree
)
321 : optimization_default_node
);
323 struct cl_optimization
*callee_opt
324 = TREE_OPTIMIZATION ((callee_tree
)
326 : optimization_default_node
);
328 if (((caller_opt
->x_optimize
> callee_opt
->x_optimize
)
329 || (caller_opt
->x_optimize_size
!= callee_opt
->x_optimize_size
))
330 /* gcc.dg/pr43564.c. Look at forced inline even in -O0. */
331 && !DECL_DISREGARD_INLINE_LIMITS (e
->callee
->decl
))
333 e
->inline_failed
= CIF_OPTIMIZATION_MISMATCH
;
338 /* Be sure that the cannot_inline_p flag is up to date. */
339 gcc_checking_assert (!e
->call_stmt
340 || (gimple_call_cannot_inline_p (e
->call_stmt
)
341 == e
->call_stmt_cannot_inline_p
)
342 /* In -flto-partition=none mode we really keep things out of
343 sync because call_stmt_cannot_inline_p is set at cgraph
344 merging when function bodies are not there yet. */
345 || (in_lto_p
&& !gimple_call_cannot_inline_p (e
->call_stmt
)));
346 if (!inlinable
&& report
)
347 report_inline_failed_reason (e
);
352 /* Return true if the edge E is inlinable during early inlining. */
355 can_early_inline_edge_p (struct cgraph_edge
*e
)
357 struct cgraph_node
*callee
= cgraph_function_or_thunk_node (e
->callee
,
359 /* Early inliner might get called at WPA stage when IPA pass adds new
360 function. In this case we can not really do any of early inlining
361 because function bodies are missing. */
362 if (!gimple_has_body_p (callee
->decl
))
364 e
->inline_failed
= CIF_BODY_NOT_AVAILABLE
;
367 /* In early inliner some of callees may not be in SSA form yet
368 (i.e. the callgraph is cyclic and we did not process
369 the callee by early inliner, yet). We don't have CIF code for this
370 case; later we will re-do the decision in the real inliner. */
371 if (!gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e
->caller
->decl
))
372 || !gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee
->decl
)))
375 fprintf (dump_file
, " edge not inlinable: not in SSA form\n");
378 if (!can_inline_edge_p (e
, true))
384 /* Return true when N is leaf function. Accept cheap builtins
385 in leaf functions. */
388 leaf_node_p (struct cgraph_node
*n
)
390 struct cgraph_edge
*e
;
391 for (e
= n
->callees
; e
; e
= e
->next_callee
)
392 if (!is_inexpensive_builtin (e
->callee
->decl
))
398 /* Return true if we are interested in inlining small function. */
401 want_early_inline_function_p (struct cgraph_edge
*e
)
403 bool want_inline
= true;
404 struct cgraph_node
*callee
= cgraph_function_or_thunk_node (e
->callee
, NULL
);
406 if (DECL_DISREGARD_INLINE_LIMITS (callee
->decl
))
408 else if (!DECL_DECLARED_INLINE_P (callee
->decl
)
409 && !flag_inline_small_functions
)
411 e
->inline_failed
= CIF_FUNCTION_NOT_INLINE_CANDIDATE
;
412 report_inline_failed_reason (e
);
417 int growth
= estimate_edge_growth (e
);
420 else if (!cgraph_maybe_hot_edge_p (e
)
424 fprintf (dump_file
, " will not early inline: %s/%i->%s/%i, "
425 "call is cold and code would grow by %i\n",
426 cgraph_node_name (e
->caller
), e
->caller
->uid
,
427 cgraph_node_name (callee
), callee
->uid
,
431 else if (!leaf_node_p (callee
)
435 fprintf (dump_file
, " will not early inline: %s/%i->%s/%i, "
436 "callee is not leaf and code would grow by %i\n",
437 cgraph_node_name (e
->caller
), e
->caller
->uid
,
438 cgraph_node_name (callee
), callee
->uid
,
442 else if (growth
> PARAM_VALUE (PARAM_EARLY_INLINING_INSNS
))
445 fprintf (dump_file
, " will not early inline: %s/%i->%s/%i, "
446 "growth %i exceeds --param early-inlining-insns\n",
447 cgraph_node_name (e
->caller
), e
->caller
->uid
,
448 cgraph_node_name (callee
), callee
->uid
,
456 /* Return true if we are interested in inlining small function.
457 When REPORT is true, report reason to dump file. */
460 want_inline_small_function_p (struct cgraph_edge
*e
, bool report
)
462 bool want_inline
= true;
463 struct cgraph_node
*callee
= cgraph_function_or_thunk_node (e
->callee
, NULL
);
465 if (DECL_DISREGARD_INLINE_LIMITS (callee
->decl
))
467 else if (!DECL_DECLARED_INLINE_P (callee
->decl
)
468 && !flag_inline_small_functions
)
470 e
->inline_failed
= CIF_FUNCTION_NOT_INLINE_CANDIDATE
;
475 int growth
= estimate_edge_growth (e
);
479 else if (DECL_DECLARED_INLINE_P (callee
->decl
)
480 && growth
>= MAX_INLINE_INSNS_SINGLE
)
482 e
->inline_failed
= CIF_MAX_INLINE_INSNS_SINGLE_LIMIT
;
485 else if (!DECL_DECLARED_INLINE_P (callee
->decl
)
486 && !flag_inline_functions
)
488 e
->inline_failed
= CIF_NOT_DECLARED_INLINED
;
491 else if (!DECL_DECLARED_INLINE_P (callee
->decl
)
492 && growth
>= MAX_INLINE_INSNS_AUTO
)
494 e
->inline_failed
= CIF_MAX_INLINE_INSNS_AUTO_LIMIT
;
497 /* If call is cold, do not inline when function body would grow.
498 Still inline when the overall unit size will shrink because the offline
499 copy of function being eliminated.
501 This is slightly wrong on aggressive side: it is entirely possible
502 that function is called many times with a context where inlining
503 reduces code size and few times with a context where inlining increase
504 code size. Resoluting growth estimate will be negative even if it
505 would make more sense to keep offline copy and do not inline into the
506 call sites that makes the code size grow.
508 When badness orders the calls in a way that code reducing calls come
509 first, this situation is not a problem at all: after inlining all
510 "good" calls, we will realize that keeping the function around is
512 else if (!cgraph_maybe_hot_edge_p (e
)
513 && (DECL_EXTERNAL (callee
->decl
)
515 /* Unlike for functions called once, we play unsafe with
516 COMDATs. We can allow that since we know functions
517 in consideration are small (and thus risk is small) and
518 moreover grow estimates already accounts that COMDAT
519 functions may or may not disappear when eliminated from
520 current unit. With good probability making aggressive
521 choice in all units is going to make overall program
524 Consequently we ask cgraph_can_remove_if_no_direct_calls_p
526 cgraph_will_be_removed_from_program_if_no_direct_calls */
528 || !cgraph_can_remove_if_no_direct_calls_p (callee
)
529 || estimate_growth (callee
) > 0))
531 e
->inline_failed
= CIF_UNLIKELY_CALL
;
535 if (!want_inline
&& report
)
536 report_inline_failed_reason (e
);
540 /* EDGE is self recursive edge.
541 We hand two cases - when function A is inlining into itself
542 or when function A is being inlined into another inliner copy of function
545 In first case OUTER_NODE points to the toplevel copy of A, while
546 in the second case OUTER_NODE points to the outermost copy of A in B.
548 In both cases we want to be extra selective since
549 inlining the call will just introduce new recursive calls to appear. */
552 want_inline_self_recursive_call_p (struct cgraph_edge
*edge
,
553 struct cgraph_node
*outer_node
,
557 char const *reason
= NULL
;
558 bool want_inline
= true;
559 int caller_freq
= CGRAPH_FREQ_BASE
;
560 int max_depth
= PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO
);
562 if (DECL_DECLARED_INLINE_P (edge
->caller
->decl
))
563 max_depth
= PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH
);
565 if (!cgraph_maybe_hot_edge_p (edge
))
567 reason
= "recursive call is cold";
570 else if (max_count
&& !outer_node
->count
)
572 reason
= "not executed in profile";
575 else if (depth
> max_depth
)
577 reason
= "--param max-inline-recursive-depth exceeded.";
581 if (outer_node
->global
.inlined_to
)
582 caller_freq
= outer_node
->callers
->frequency
;
586 /* Inlining of self recursive function into copy of itself within other function
587 is transformation similar to loop peeling.
589 Peeling is profitable if we can inline enough copies to make probability
590 of actual call to the self recursive function very small. Be sure that
591 the probability of recursion is small.
593 We ensure that the frequency of recursing is at most 1 - (1/max_depth).
594 This way the expected number of recision is at most max_depth. */
597 int max_prob
= CGRAPH_FREQ_BASE
- ((CGRAPH_FREQ_BASE
+ max_depth
- 1)
600 for (i
= 1; i
< depth
; i
++)
601 max_prob
= max_prob
* max_prob
/ CGRAPH_FREQ_BASE
;
603 && (edge
->count
* CGRAPH_FREQ_BASE
/ outer_node
->count
606 reason
= "profile of recursive call is too large";
610 && (edge
->frequency
* CGRAPH_FREQ_BASE
/ caller_freq
613 reason
= "frequency of recursive call is too large";
617 /* Recursive inlining, i.e. equivalent of unrolling, is profitable if recursion
618 depth is large. We reduce function call overhead and increase chances that
619 things fit in hardware return predictor.
621 Recursive inlining might however increase cost of stack frame setup
622 actually slowing down functions whose recursion tree is wide rather than
625 Deciding reliably on when to do recursive inlining without profile feedback
626 is tricky. For now we disable recursive inlining when probability of self
629 Recursive inlining of self recursive call within loop also results in large loop
630 depths that generally optimize badly. We may want to throttle down inlining
631 in those cases. In particular this seems to happen in one of libstdc++ rb tree
636 && (edge
->count
* 100 / outer_node
->count
637 <= PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY
)))
639 reason
= "profile of recursive call is too small";
643 && (edge
->frequency
* 100 / caller_freq
644 <= PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY
)))
646 reason
= "frequency of recursive call is too small";
650 if (!want_inline
&& dump_file
)
651 fprintf (dump_file
, " not inlining recursively: %s\n", reason
);
655 /* Return true when NODE has caller other than EDGE.
656 Worker for cgraph_for_node_and_aliases. */
659 check_caller_edge (struct cgraph_node
*node
, void *edge
)
661 return (node
->callers
662 && node
->callers
!= edge
);
666 /* Decide if NODE is called once inlining it would eliminate need
667 for the offline copy of function. */
670 want_inline_function_called_once_p (struct cgraph_node
*node
)
672 struct cgraph_node
*function
= cgraph_function_or_thunk_node (node
, NULL
);
673 /* Already inlined? */
674 if (function
->global
.inlined_to
)
676 /* Zero or more then one callers? */
678 || node
->callers
->next_caller
)
680 /* Maybe other aliases has more direct calls. */
681 if (cgraph_for_node_and_aliases (node
, check_caller_edge
, node
->callers
, true))
683 /* Recursive call makes no sense to inline. */
684 if (cgraph_edge_recursive_p (node
->callers
))
686 /* External functions are not really in the unit, so inlining
687 them when called once would just increase the program size. */
688 if (DECL_EXTERNAL (function
->decl
))
690 /* Offline body must be optimized out. */
691 if (!cgraph_will_be_removed_from_program_if_no_direct_calls (function
))
693 if (!can_inline_edge_p (node
->callers
, true))
699 /* Return relative time improvement for inlining EDGE in range
703 relative_time_benefit (struct inline_summary
*callee_info
,
704 struct cgraph_edge
*edge
,
708 gcov_type uninlined_call_time
;
710 uninlined_call_time
=
713 + inline_edge_summary (edge
)->call_stmt_time
) * edge
->frequency
714 + CGRAPH_FREQ_BASE
/ 2) / CGRAPH_FREQ_BASE
;
715 /* Compute relative time benefit, i.e. how much the call becomes faster.
716 ??? perhaps computing how much the caller+calle together become faster
717 would lead to more realistic results. */
718 if (!uninlined_call_time
)
719 uninlined_call_time
= 1;
721 (uninlined_call_time
- time_growth
) * 256 / (uninlined_call_time
);
722 relbenefit
= MIN (relbenefit
, 512);
723 relbenefit
= MAX (relbenefit
, 1);
728 /* A cost model driving the inlining heuristics in a way so the edges with
729 smallest badness are inlined first. After each inlining is performed
730 the costs of all caller edges of nodes affected are recomputed so the
731 metrics may accurately depend on values such as number of inlinable callers
732 of the function or function body size. */
735 edge_badness (struct cgraph_edge
*edge
, bool dump
)
738 int growth
, time_growth
;
739 struct cgraph_node
*callee
= cgraph_function_or_thunk_node (edge
->callee
,
741 struct inline_summary
*callee_info
= inline_summary (callee
);
743 if (DECL_DISREGARD_INLINE_LIMITS (callee
->decl
))
746 growth
= estimate_edge_growth (edge
);
747 time_growth
= estimate_edge_time (edge
);
751 fprintf (dump_file
, " Badness calculation for %s -> %s\n",
752 cgraph_node_name (edge
->caller
),
753 cgraph_node_name (callee
));
754 fprintf (dump_file
, " size growth %i, time growth %i\n",
759 /* Always prefer inlining saving code size. */
762 badness
= INT_MIN
/ 2 + growth
;
764 fprintf (dump_file
, " %i: Growth %i <= 0\n", (int) badness
,
768 /* When profiling is available, compute badness as:
770 relative_edge_count * relative_time_benefit
771 goodness = -------------------------------------------
775 The fraction is upside down, becuase on edge counts and time beneits
776 the bounds are known. Edge growth is essentially unlimited. */
780 int relbenefit
= relative_time_benefit (callee_info
, edge
, time_growth
);
783 ((double) edge
->count
* INT_MIN
/ 2 / max_count
/ 512) *
784 relative_time_benefit (callee_info
, edge
, time_growth
)) / growth
;
786 /* Be sure that insanity of the profile won't lead to increasing counts
787 in the scalling and thus to overflow in the computation above. */
788 gcc_assert (max_count
>= edge
->count
);
792 " %i (relative %f): profile info. Relative count %f"
793 " * Relative benefit %f\n",
794 (int) badness
, (double) badness
/ INT_MIN
,
795 (double) edge
->count
/ max_count
,
796 relbenefit
* 100 / 256.0);
800 /* When function local profile is available. Compute badness as:
804 badness = -------------------------------------- + growth_for-all
805 relative_time_benefit * edge_frequency
808 else if (flag_guess_branch_prob
)
810 int div
= edge
->frequency
* (1<<10) / CGRAPH_FREQ_MAX
;
814 gcc_checking_assert (edge
->frequency
<= CGRAPH_FREQ_MAX
);
815 div
*= relative_time_benefit (callee_info
, edge
, time_growth
);
817 /* frequency is normalized in range 1...2^10.
818 relbenefit in range 1...2^9
819 DIV should be in range 1....2^19. */
820 gcc_checking_assert (div
>= 1 && div
<= (1<<19));
822 /* Result must be integer in range 0...INT_MAX.
823 Set the base of fixed point calculation so we don't lose much of
824 precision for small bandesses (those are interesting) yet we don't
825 overflow for growths that are still in interesting range.
827 Fixed point arithmetic with point at 8th bit. */
828 badness
= ((gcov_type
)growth
) * (1<<(19+8));
829 badness
= (badness
+ div
/ 2) / div
;
831 /* Overall growth of inlining all calls of function matters: we want to
832 inline so offline copy of function is no longer needed.
834 Additionally functions that can be fully inlined without much of
835 effort are better inline candidates than functions that can be fully
836 inlined only after noticeable overall unit growths. The latter
837 are better in a sense compressing of code size by factoring out common
838 code into separate function shared by multiple code paths.
840 We might mix the valud into the fraction by taking into account
841 relative growth of the unit, but for now just add the number
842 into resulting fraction. */
843 if (badness
> INT_MAX
/ 2)
845 badness
= INT_MAX
/ 2;
847 fprintf (dump_file
, "Badness overflow\n");
849 growth_for_all
= estimate_growth (callee
);
850 badness
+= growth_for_all
;
854 " %i: guessed profile. frequency %f, overall growth %i,"
855 " benefit %f%%, divisor %i\n",
856 (int) badness
, (double)edge
->frequency
/ CGRAPH_FREQ_BASE
, growth_for_all
,
857 relative_time_benefit (callee_info
, edge
, time_growth
) * 100 / 256.0, div
);
860 /* When function local profile is not available or it does not give
861 useful information (ie frequency is zero), base the cost on
862 loop nest and overall size growth, so we optimize for overall number
863 of functions fully inlined in program. */
866 int nest
= MIN (inline_edge_summary (edge
)->loop_depth
, 8);
867 badness
= estimate_growth (callee
) * 256;
869 /* Decrease badness if call is nested. */
877 fprintf (dump_file
, " %i: no profile. nest %i\n", (int) badness
,
881 /* Ensure that we did not overflow in all the fixed point math above. */
882 gcc_assert (badness
>= INT_MIN
);
883 gcc_assert (badness
<= INT_MAX
- 1);
884 /* Make recursive inlining happen always after other inlining is done. */
885 if (cgraph_edge_recursive_p (edge
))
891 /* Recompute badness of EDGE and update its key in HEAP if needed. */
893 update_edge_key (fibheap_t heap
, struct cgraph_edge
*edge
)
895 int badness
= edge_badness (edge
, false);
898 fibnode_t n
= (fibnode_t
) edge
->aux
;
899 gcc_checking_assert (n
->data
== edge
);
901 /* fibheap_replace_key only decrease the keys.
902 When we increase the key we do not update heap
903 and instead re-insert the element once it becomes
904 a minimum of heap. */
905 if (badness
< n
->key
)
907 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
910 " decreasing badness %s/%i -> %s/%i, %i to %i\n",
911 cgraph_node_name (edge
->caller
), edge
->caller
->uid
,
912 cgraph_node_name (edge
->callee
), edge
->callee
->uid
,
916 fibheap_replace_key (heap
, n
, badness
);
917 gcc_checking_assert (n
->key
== badness
);
922 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
925 " enqueuing call %s/%i -> %s/%i, badness %i\n",
926 cgraph_node_name (edge
->caller
), edge
->caller
->uid
,
927 cgraph_node_name (edge
->callee
), edge
->callee
->uid
,
930 edge
->aux
= fibheap_insert (heap
, badness
, edge
);
936 All caller edges needs to be resetted because
937 size estimates change. Similarly callees needs reset
938 because better context may be known. */
941 reset_edge_caches (struct cgraph_node
*node
)
943 struct cgraph_edge
*edge
;
944 struct cgraph_edge
*e
= node
->callees
;
945 struct cgraph_node
*where
= node
;
949 if (where
->global
.inlined_to
)
950 where
= where
->global
.inlined_to
;
952 /* WHERE body size has changed, the cached growth is invalid. */
953 reset_node_growth_cache (where
);
955 for (edge
= where
->callers
; edge
; edge
= edge
->next_caller
)
956 if (edge
->inline_failed
)
957 reset_edge_growth_cache (edge
);
958 for (i
= 0; ipa_ref_list_refering_iterate (&where
->ref_list
, i
, ref
); i
++)
959 if (ref
->use
== IPA_REF_ALIAS
)
960 reset_edge_caches (ipa_ref_refering_node (ref
));
966 if (!e
->inline_failed
&& e
->callee
->callees
)
967 e
= e
->callee
->callees
;
970 if (e
->inline_failed
)
971 reset_edge_growth_cache (e
);
978 if (e
->caller
== node
)
980 e
= e
->caller
->callers
;
982 while (!e
->next_callee
);
988 /* Recompute HEAP nodes for each of caller of NODE.
989 UPDATED_NODES track nodes we already visited, to avoid redundant work.
990 When CHECK_INLINABLITY_FOR is set, re-check for specified edge that
991 it is inlinable. Otherwise check all edges. */
994 update_caller_keys (fibheap_t heap
, struct cgraph_node
*node
,
995 bitmap updated_nodes
,
996 struct cgraph_edge
*check_inlinablity_for
)
998 struct cgraph_edge
*edge
;
1000 struct ipa_ref
*ref
;
1002 if ((!node
->alias
&& !inline_summary (node
)->inlinable
)
1003 || cgraph_function_body_availability (node
) <= AVAIL_OVERWRITABLE
1004 || node
->global
.inlined_to
)
1006 if (!bitmap_set_bit (updated_nodes
, node
->uid
))
1009 for (i
= 0; ipa_ref_list_refering_iterate (&node
->ref_list
, i
, ref
); i
++)
1010 if (ref
->use
== IPA_REF_ALIAS
)
1012 struct cgraph_node
*alias
= ipa_ref_refering_node (ref
);
1013 update_caller_keys (heap
, alias
, updated_nodes
, check_inlinablity_for
);
1016 for (edge
= node
->callers
; edge
; edge
= edge
->next_caller
)
1017 if (edge
->inline_failed
)
1019 if (!check_inlinablity_for
1020 || check_inlinablity_for
== edge
)
1022 if (can_inline_edge_p (edge
, false)
1023 && want_inline_small_function_p (edge
, false))
1024 update_edge_key (heap
, edge
);
1027 report_inline_failed_reason (edge
);
1028 fibheap_delete_node (heap
, (fibnode_t
) edge
->aux
);
1033 update_edge_key (heap
, edge
);
1037 /* Recompute HEAP nodes for each uninlined call in NODE.
1038 This is used when we know that edge badnesses are going only to increase
1039 (we introduced new call site) and thus all we need is to insert newly
1040 created edges into heap. */
1043 update_callee_keys (fibheap_t heap
, struct cgraph_node
*node
,
1044 bitmap updated_nodes
)
1046 struct cgraph_edge
*e
= node
->callees
;
1051 if (!e
->inline_failed
&& e
->callee
->callees
)
1052 e
= e
->callee
->callees
;
1055 enum availability avail
;
1056 struct cgraph_node
*callee
;
1057 /* We do not reset callee growth cache here. Since we added a new call,
1058 growth chould have just increased and consequentely badness metric
1059 don't need updating. */
1060 if (e
->inline_failed
1061 && (callee
= cgraph_function_or_thunk_node (e
->callee
, &avail
))
1062 && inline_summary (callee
)->inlinable
1063 && cgraph_function_body_availability (callee
) >= AVAIL_AVAILABLE
1064 && !bitmap_bit_p (updated_nodes
, callee
->uid
))
1066 if (can_inline_edge_p (e
, false)
1067 && want_inline_small_function_p (e
, false))
1068 update_edge_key (heap
, e
);
1071 report_inline_failed_reason (e
);
1072 fibheap_delete_node (heap
, (fibnode_t
) e
->aux
);
1082 if (e
->caller
== node
)
1084 e
= e
->caller
->callers
;
1086 while (!e
->next_callee
);
1092 /* Recompute heap nodes for each of caller edges of each of callees.
1093 Walk recursively into all inline clones. */
1096 update_all_callee_keys (fibheap_t heap
, struct cgraph_node
*node
,
1097 bitmap updated_nodes
)
1099 struct cgraph_edge
*e
= node
->callees
;
1103 if (!e
->inline_failed
&& e
->callee
->callees
)
1104 e
= e
->callee
->callees
;
1107 struct cgraph_node
*callee
= cgraph_function_or_thunk_node (e
->callee
,
1110 /* We inlined and thus callees might have different number of calls.
1111 Reset their caches */
1112 reset_node_growth_cache (callee
);
1113 if (e
->inline_failed
)
1114 update_caller_keys (heap
, callee
, updated_nodes
, e
);
1121 if (e
->caller
== node
)
1123 e
= e
->caller
->callers
;
1125 while (!e
->next_callee
);
1131 /* Enqueue all recursive calls from NODE into priority queue depending on
1132 how likely we want to recursively inline the call. */
1135 lookup_recursive_calls (struct cgraph_node
*node
, struct cgraph_node
*where
,
1138 struct cgraph_edge
*e
;
1139 enum availability avail
;
1141 for (e
= where
->callees
; e
; e
= e
->next_callee
)
1142 if (e
->callee
== node
1143 || (cgraph_function_or_thunk_node (e
->callee
, &avail
) == node
1144 && avail
> AVAIL_OVERWRITABLE
))
1146 /* When profile feedback is available, prioritize by expected number
1148 fibheap_insert (heap
,
1149 !max_count
? -e
->frequency
1150 : -(e
->count
/ ((max_count
+ (1<<24) - 1) / (1<<24))),
1153 for (e
= where
->callees
; e
; e
= e
->next_callee
)
1154 if (!e
->inline_failed
)
1155 lookup_recursive_calls (node
, e
->callee
, heap
);
1158 /* Decide on recursive inlining: in the case function has recursive calls,
1159 inline until body size reaches given argument. If any new indirect edges
1160 are discovered in the process, add them to *NEW_EDGES, unless NEW_EDGES
1164 recursive_inlining (struct cgraph_edge
*edge
,
1165 VEC (cgraph_edge_p
, heap
) **new_edges
)
1167 int limit
= PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO
);
1169 struct cgraph_node
*node
;
1170 struct cgraph_edge
*e
;
1171 struct cgraph_node
*master_clone
= NULL
, *next
;
1175 node
= edge
->caller
;
1176 if (node
->global
.inlined_to
)
1177 node
= node
->global
.inlined_to
;
1179 if (DECL_DECLARED_INLINE_P (node
->decl
))
1180 limit
= PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE
);
1182 /* Make sure that function is small enough to be considered for inlining. */
1183 if (estimate_size_after_inlining (node
, edge
) >= limit
)
1185 heap
= fibheap_new ();
1186 lookup_recursive_calls (node
, node
, heap
);
1187 if (fibheap_empty (heap
))
1189 fibheap_delete (heap
);
1195 " Performing recursive inlining on %s\n",
1196 cgraph_node_name (node
));
1198 /* Do the inlining and update list of recursive call during process. */
1199 while (!fibheap_empty (heap
))
1201 struct cgraph_edge
*curr
1202 = (struct cgraph_edge
*) fibheap_extract_min (heap
);
1203 struct cgraph_node
*cnode
;
1205 if (estimate_size_after_inlining (node
, curr
) > limit
)
1208 if (!can_inline_edge_p (curr
, true))
1212 for (cnode
= curr
->caller
;
1213 cnode
->global
.inlined_to
; cnode
= cnode
->callers
->caller
)
1215 == cgraph_function_or_thunk_node (curr
->callee
, NULL
)->decl
)
1218 if (!want_inline_self_recursive_call_p (curr
, node
, false, depth
))
1224 " Inlining call of depth %i", depth
);
1227 fprintf (dump_file
, " called approx. %.2f times per call",
1228 (double)curr
->count
/ node
->count
);
1230 fprintf (dump_file
, "\n");
1234 /* We need original clone to copy around. */
1235 master_clone
= cgraph_clone_node (node
, node
->decl
,
1236 node
->count
, CGRAPH_FREQ_BASE
,
1238 for (e
= master_clone
->callees
; e
; e
= e
->next_callee
)
1239 if (!e
->inline_failed
)
1240 clone_inlined_nodes (e
, true, false, NULL
);
1243 cgraph_redirect_edge_callee (curr
, master_clone
);
1244 inline_call (curr
, false, new_edges
, &overall_size
);
1245 lookup_recursive_calls (node
, curr
->callee
, heap
);
1249 if (!fibheap_empty (heap
) && dump_file
)
1250 fprintf (dump_file
, " Recursive inlining growth limit met.\n");
1251 fibheap_delete (heap
);
1258 "\n Inlined %i times, "
1259 "body grown from size %i to %i, time %i to %i\n", n
,
1260 inline_summary (master_clone
)->size
, inline_summary (node
)->size
,
1261 inline_summary (master_clone
)->time
, inline_summary (node
)->time
);
1263 /* Remove master clone we used for inlining. We rely that clones inlined
1264 into master clone gets queued just before master clone so we don't
1266 for (node
= cgraph_nodes
; node
!= master_clone
;
1270 if (node
->global
.inlined_to
== master_clone
)
1271 cgraph_remove_node (node
);
1273 cgraph_remove_node (master_clone
);
1278 /* Given whole compilation unit estimate of INSNS, compute how large we can
1279 allow the unit to grow. */
1282 compute_max_insns (int insns
)
1284 int max_insns
= insns
;
1285 if (max_insns
< PARAM_VALUE (PARAM_LARGE_UNIT_INSNS
))
1286 max_insns
= PARAM_VALUE (PARAM_LARGE_UNIT_INSNS
);
1288 return ((HOST_WIDEST_INT
) max_insns
1289 * (100 + PARAM_VALUE (PARAM_INLINE_UNIT_GROWTH
)) / 100);
1293 /* Compute badness of all edges in NEW_EDGES and add them to the HEAP. */
1296 add_new_edges_to_heap (fibheap_t heap
, VEC (cgraph_edge_p
, heap
) *new_edges
)
1298 while (VEC_length (cgraph_edge_p
, new_edges
) > 0)
1300 struct cgraph_edge
*edge
= VEC_pop (cgraph_edge_p
, new_edges
);
1302 gcc_assert (!edge
->aux
);
1303 if (edge
->inline_failed
1304 && can_inline_edge_p (edge
, true)
1305 && want_inline_small_function_p (edge
, true))
1306 edge
->aux
= fibheap_insert (heap
, edge_badness (edge
, false), edge
);
1311 /* We use greedy algorithm for inlining of small functions:
1312 All inline candidates are put into prioritized heap ordered in
1315 The inlining of small functions is bounded by unit growth parameters. */
1318 inline_small_functions (void)
1320 struct cgraph_node
*node
;
1321 struct cgraph_edge
*edge
;
1322 fibheap_t heap
= fibheap_new ();
1323 bitmap updated_nodes
= BITMAP_ALLOC (NULL
);
1324 int min_size
, max_size
;
1325 VEC (cgraph_edge_p
, heap
) *new_indirect_edges
= NULL
;
1326 int initial_size
= 0;
1328 if (flag_indirect_inlining
)
1329 new_indirect_edges
= VEC_alloc (cgraph_edge_p
, heap
, 8);
1333 "\nDeciding on inlining of small functions. Starting with size %i.\n",
1336 /* Compute overall unit size and other global parameters used by badness
1340 initialize_growth_caches ();
1342 FOR_EACH_DEFINED_FUNCTION (node
)
1343 if (!node
->global
.inlined_to
)
1345 if (cgraph_function_with_gimple_body_p (node
)
1346 || node
->thunk
.thunk_p
)
1348 struct inline_summary
*info
= inline_summary (node
);
1350 if (!DECL_EXTERNAL (node
->decl
))
1351 initial_size
+= info
->size
;
1354 for (edge
= node
->callers
; edge
; edge
= edge
->next_caller
)
1355 if (max_count
< edge
->count
)
1356 max_count
= edge
->count
;
1359 overall_size
= initial_size
;
1360 max_size
= compute_max_insns (overall_size
);
1361 min_size
= overall_size
;
1363 /* Populate the heeap with all edges we might inline. */
1365 FOR_EACH_DEFINED_FUNCTION (node
)
1366 if (!node
->global
.inlined_to
)
1369 fprintf (dump_file
, "Enqueueing calls of %s/%i.\n",
1370 cgraph_node_name (node
), node
->uid
);
1372 for (edge
= node
->callers
; edge
; edge
= edge
->next_caller
)
1373 if (edge
->inline_failed
1374 && can_inline_edge_p (edge
, true)
1375 && want_inline_small_function_p (edge
, true)
1376 && edge
->inline_failed
)
1378 gcc_assert (!edge
->aux
);
1379 update_edge_key (heap
, edge
);
1383 gcc_assert (in_lto_p
1385 || (profile_info
&& flag_branch_probabilities
));
1387 while (!fibheap_empty (heap
))
1389 int old_size
= overall_size
;
1390 struct cgraph_node
*where
, *callee
;
1391 int badness
= fibheap_min_key (heap
);
1392 int current_badness
;
1396 edge
= (struct cgraph_edge
*) fibheap_extract_min (heap
);
1397 gcc_assert (edge
->aux
);
1399 if (!edge
->inline_failed
)
1402 /* Be sure that caches are maintained consistent.
1403 We can not make this ENABLE_CHECKING only because it cause differnt
1404 updates of the fibheap queue. */
1405 cached_badness
= edge_badness (edge
, false);
1406 reset_edge_growth_cache (edge
);
1407 reset_node_growth_cache (edge
->callee
);
1409 /* When updating the edge costs, we only decrease badness in the keys.
1410 Increases of badness are handled lazilly; when we see key with out
1411 of date value on it, we re-insert it now. */
1412 current_badness
= edge_badness (edge
, false);
1413 gcc_assert (cached_badness
== current_badness
);
1414 gcc_assert (current_badness
>= badness
);
1415 if (current_badness
!= badness
)
1417 edge
->aux
= fibheap_insert (heap
, current_badness
, edge
);
1421 if (!can_inline_edge_p (edge
, true))
1424 callee
= cgraph_function_or_thunk_node (edge
->callee
, NULL
);
1425 growth
= estimate_edge_growth (edge
);
1429 "\nConsidering %s with %i size\n",
1430 cgraph_node_name (callee
),
1431 inline_summary (callee
)->size
);
1433 " to be inlined into %s in %s:%i\n"
1434 " Estimated growth after inlined into all is %+i insns.\n"
1435 " Estimated badness is %i, frequency %.2f.\n",
1436 cgraph_node_name (edge
->caller
),
1437 flag_wpa
? "unknown"
1438 : gimple_filename ((const_gimple
) edge
->call_stmt
),
1440 : gimple_lineno ((const_gimple
) edge
->call_stmt
),
1441 estimate_growth (callee
),
1443 edge
->frequency
/ (double)CGRAPH_FREQ_BASE
);
1445 fprintf (dump_file
," Called "HOST_WIDEST_INT_PRINT_DEC
"x\n",
1447 if (dump_flags
& TDF_DETAILS
)
1448 edge_badness (edge
, true);
1451 if (overall_size
+ growth
> max_size
1452 && !DECL_DISREGARD_INLINE_LIMITS (callee
->decl
))
1454 edge
->inline_failed
= CIF_INLINE_UNIT_GROWTH_LIMIT
;
1455 report_inline_failed_reason (edge
);
1459 if (!want_inline_small_function_p (edge
, true))
1462 /* Heuristics for inlining small functions works poorly for
1463 recursive calls where we do efect similar to loop unrolling.
1464 When inliing such edge seems profitable, leave decision on
1465 specific inliner. */
1466 if (cgraph_edge_recursive_p (edge
))
1468 where
= edge
->caller
;
1469 if (where
->global
.inlined_to
)
1470 where
= where
->global
.inlined_to
;
1471 if (!recursive_inlining (edge
,
1472 flag_indirect_inlining
1473 ? &new_indirect_edges
: NULL
))
1475 edge
->inline_failed
= CIF_RECURSIVE_INLINING
;
1478 reset_edge_caches (where
);
1479 /* Recursive inliner inlines all recursive calls of the function
1480 at once. Consequently we need to update all callee keys. */
1481 if (flag_indirect_inlining
)
1482 add_new_edges_to_heap (heap
, new_indirect_edges
);
1483 update_all_callee_keys (heap
, where
, updated_nodes
);
1487 struct cgraph_node
*outer_node
= NULL
;
1490 /* Consider the case where self recursive function A is inlined into B.
1491 This is desired optimization in some cases, since it leads to effect
1492 similar of loop peeling and we might completely optimize out the
1493 recursive call. However we must be extra selective. */
1495 where
= edge
->caller
;
1496 while (where
->global
.inlined_to
)
1498 if (where
->decl
== callee
->decl
)
1499 outer_node
= where
, depth
++;
1500 where
= where
->callers
->caller
;
1503 && !want_inline_self_recursive_call_p (edge
, outer_node
,
1507 = (DECL_DISREGARD_INLINE_LIMITS (edge
->callee
->decl
)
1508 ? CIF_RECURSIVE_INLINING
: CIF_UNSPECIFIED
);
1511 else if (depth
&& dump_file
)
1512 fprintf (dump_file
, " Peeling recursion with depth %i\n", depth
);
1514 gcc_checking_assert (!callee
->global
.inlined_to
);
1515 inline_call (edge
, true, &new_indirect_edges
, &overall_size
);
1516 if (flag_indirect_inlining
)
1517 add_new_edges_to_heap (heap
, new_indirect_edges
);
1519 reset_edge_caches (edge
->callee
);
1520 reset_node_growth_cache (callee
);
1522 /* We inlined last offline copy to the body. This might lead
1523 to callees of function having fewer call sites and thus they
1526 FIXME: the callee size could also shrink because more information
1527 is propagated from caller. We don't track when this happen and
1528 thus we need to recompute everything all the time. Once this is
1529 solved, "|| 1" should go away. */
1530 if (callee
->global
.inlined_to
|| 1)
1531 update_all_callee_keys (heap
, callee
, updated_nodes
);
1533 update_callee_keys (heap
, edge
->callee
, updated_nodes
);
1535 where
= edge
->caller
;
1536 if (where
->global
.inlined_to
)
1537 where
= where
->global
.inlined_to
;
1539 /* Our profitability metric can depend on local properties
1540 such as number of inlinable calls and size of the function body.
1541 After inlining these properties might change for the function we
1542 inlined into (since it's body size changed) and for the functions
1543 called by function we inlined (since number of it inlinable callers
1545 update_caller_keys (heap
, where
, updated_nodes
, NULL
);
1547 /* We removed one call of the function we just inlined. If offline
1548 copy is still needed, be sure to update the keys. */
1549 if (callee
!= where
&& !callee
->global
.inlined_to
)
1550 update_caller_keys (heap
, callee
, updated_nodes
, NULL
);
1551 bitmap_clear (updated_nodes
);
1556 " Inlined into %s which now has time %i and size %i,"
1557 "net change of %+i.\n",
1558 cgraph_node_name (edge
->caller
),
1559 inline_summary (edge
->caller
)->time
,
1560 inline_summary (edge
->caller
)->size
,
1561 overall_size
- old_size
);
1563 if (min_size
> overall_size
)
1565 min_size
= overall_size
;
1566 max_size
= compute_max_insns (min_size
);
1569 fprintf (dump_file
, "New minimal size reached: %i\n", min_size
);
1573 free_growth_caches ();
1574 if (new_indirect_edges
)
1575 VEC_free (cgraph_edge_p
, heap
, new_indirect_edges
);
1576 fibheap_delete (heap
);
1579 "Unit growth for small function inlining: %i->%i (%i%%)\n",
1580 initial_size
, overall_size
,
1581 initial_size
? overall_size
* 100 / (initial_size
) - 100: 0);
1582 BITMAP_FREE (updated_nodes
);
1585 /* Flatten NODE. Performed both during early inlining and
1586 at IPA inlining time. */
1589 flatten_function (struct cgraph_node
*node
, bool early
)
1591 struct cgraph_edge
*e
;
1593 /* We shouldn't be called recursively when we are being processed. */
1594 gcc_assert (node
->aux
== NULL
);
1596 node
->aux
= (void *) node
;
1598 for (e
= node
->callees
; e
; e
= e
->next_callee
)
1600 struct cgraph_node
*orig_callee
;
1601 struct cgraph_node
*callee
= cgraph_function_or_thunk_node (e
->callee
, NULL
);
1603 /* We've hit cycle? It is time to give up. */
1608 "Not inlining %s into %s to avoid cycle.\n",
1609 cgraph_node_name (callee
),
1610 cgraph_node_name (e
->caller
));
1611 e
->inline_failed
= CIF_RECURSIVE_INLINING
;
1615 /* When the edge is already inlined, we just need to recurse into
1616 it in order to fully flatten the leaves. */
1617 if (!e
->inline_failed
)
1619 flatten_function (callee
, early
);
1623 /* Flatten attribute needs to be processed during late inlining. For
1624 extra code quality we however do flattening during early optimization,
1627 ? !can_inline_edge_p (e
, true)
1628 : !can_early_inline_edge_p (e
))
1631 if (cgraph_edge_recursive_p (e
))
1634 fprintf (dump_file
, "Not inlining: recursive call.\n");
1638 if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node
->decl
))
1639 != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (callee
->decl
)))
1642 fprintf (dump_file
, "Not inlining: SSA form does not match.\n");
1646 /* Inline the edge and flatten the inline clone. Avoid
1647 recursing through the original node if the node was cloned. */
1649 fprintf (dump_file
, " Inlining %s into %s.\n",
1650 cgraph_node_name (callee
),
1651 cgraph_node_name (e
->caller
));
1652 orig_callee
= callee
;
1653 inline_call (e
, true, NULL
, NULL
);
1654 if (e
->callee
!= orig_callee
)
1655 orig_callee
->aux
= (void *) node
;
1656 flatten_function (e
->callee
, early
);
1657 if (e
->callee
!= orig_callee
)
1658 orig_callee
->aux
= NULL
;
1664 /* Decide on the inlining. We do so in the topological order to avoid
1665 expenses on updating data structures. */
1670 struct cgraph_node
*node
;
1672 struct cgraph_node
**order
=
1673 XCNEWVEC (struct cgraph_node
*, cgraph_n_nodes
);
1676 if (in_lto_p
&& optimize
)
1677 ipa_update_after_lto_read ();
1680 dump_inline_summaries (dump_file
);
1682 nnodes
= ipa_reverse_postorder (order
);
1684 for (node
= cgraph_nodes
; node
; node
= node
->next
)
1688 fprintf (dump_file
, "\nFlattening functions:\n");
1690 /* In the first pass handle functions to be flattened. Do this with
1691 a priority so none of our later choices will make this impossible. */
1692 for (i
= nnodes
- 1; i
>= 0; i
--)
1696 /* Handle nodes to be flattened.
1697 Ideally when processing callees we stop inlining at the
1698 entry of cycles, possibly cloning that entry point and
1699 try to flatten itself turning it into a self-recursive
1701 if (lookup_attribute ("flatten",
1702 DECL_ATTRIBUTES (node
->decl
)) != NULL
)
1706 "Flattening %s\n", cgraph_node_name (node
));
1707 flatten_function (node
, false);
1711 inline_small_functions ();
1712 cgraph_remove_unreachable_nodes (true, dump_file
);
1715 /* We already perform some inlining of functions called once during
1716 inlining small functions above. After unreachable nodes are removed,
1717 we still might do a quick check that nothing new is found. */
1718 if (flag_inline_functions_called_once
)
1722 fprintf (dump_file
, "\nDeciding on functions called once:\n");
1724 /* Inlining one function called once has good chance of preventing
1725 inlining other function into the same callee. Ideally we should
1726 work in priority order, but probably inlining hot functions first
1727 is good cut without the extra pain of maintaining the queue.
1729 ??? this is not really fitting the bill perfectly: inlining function
1730 into callee often leads to better optimization of callee due to
1731 increased context for optimization.
1732 For example if main() function calls a function that outputs help
1733 and then function that does the main optmization, we should inline
1734 the second with priority even if both calls are cold by themselves.
1736 We probably want to implement new predicate replacing our use of
1737 maybe_hot_edge interpreted as maybe_hot_edge || callee is known
1739 for (cold
= 0; cold
<= 1; cold
++)
1741 for (node
= cgraph_nodes
; node
; node
= node
->next
)
1743 if (want_inline_function_called_once_p (node
)
1745 || cgraph_maybe_hot_edge_p (node
->callers
)))
1747 struct cgraph_node
*caller
= node
->callers
->caller
;
1752 "\nInlining %s size %i.\n",
1753 cgraph_node_name (node
), inline_summary (node
)->size
);
1755 " Called once from %s %i insns.\n",
1756 cgraph_node_name (node
->callers
->caller
),
1757 inline_summary (node
->callers
->caller
)->size
);
1760 inline_call (node
->callers
, true, NULL
, NULL
);
1763 " Inlined into %s which now has %i size\n",
1764 cgraph_node_name (caller
),
1765 inline_summary (caller
)->size
);
1771 /* Free ipa-prop structures if they are no longer needed. */
1773 ipa_free_all_structures_after_iinln ();
1777 "\nInlined %i calls, eliminated %i functions\n\n",
1778 ncalls_inlined
, nfunctions_inlined
);
1781 dump_inline_summaries (dump_file
);
1782 /* In WPA we use inline summaries for partitioning process. */
1784 inline_free_summary ();
1788 /* Inline always-inline function calls in NODE. */
1791 inline_always_inline_functions (struct cgraph_node
*node
)
1793 struct cgraph_edge
*e
;
1794 bool inlined
= false;
1796 for (e
= node
->callees
; e
; e
= e
->next_callee
)
1798 struct cgraph_node
*callee
= cgraph_function_or_thunk_node (e
->callee
, NULL
);
1799 if (!DECL_DISREGARD_INLINE_LIMITS (callee
->decl
))
1802 if (cgraph_edge_recursive_p (e
))
1805 fprintf (dump_file
, " Not inlining recursive call to %s.\n",
1806 cgraph_node_name (e
->callee
));
1807 e
->inline_failed
= CIF_RECURSIVE_INLINING
;
1811 if (!can_early_inline_edge_p (e
))
1815 fprintf (dump_file
, " Inlining %s into %s (always_inline).\n",
1816 cgraph_node_name (e
->callee
),
1817 cgraph_node_name (e
->caller
));
1818 inline_call (e
, true, NULL
, NULL
);
1825 /* Decide on the inlining. We do so in the topological order to avoid
1826 expenses on updating data structures. */
1829 early_inline_small_functions (struct cgraph_node
*node
)
1831 struct cgraph_edge
*e
;
1832 bool inlined
= false;
1834 for (e
= node
->callees
; e
; e
= e
->next_callee
)
1836 struct cgraph_node
*callee
= cgraph_function_or_thunk_node (e
->callee
, NULL
);
1837 if (!inline_summary (callee
)->inlinable
1838 || !e
->inline_failed
)
1841 /* Do not consider functions not declared inline. */
1842 if (!DECL_DECLARED_INLINE_P (callee
->decl
)
1843 && !flag_inline_small_functions
1844 && !flag_inline_functions
)
1848 fprintf (dump_file
, "Considering inline candidate %s.\n",
1849 cgraph_node_name (callee
));
1851 if (!can_early_inline_edge_p (e
))
1854 if (cgraph_edge_recursive_p (e
))
1857 fprintf (dump_file
, " Not inlining: recursive call.\n");
1861 if (!want_early_inline_function_p (e
))
1865 fprintf (dump_file
, " Inlining %s into %s.\n",
1866 cgraph_node_name (callee
),
1867 cgraph_node_name (e
->caller
));
1868 inline_call (e
, true, NULL
, NULL
);
1875 /* Do inlining of small functions. Doing so early helps profiling and other
1876 passes to be somewhat more effective and avoids some code duplication in
1877 later real inlining pass for testcases with very many function calls. */
1879 early_inliner (void)
1881 struct cgraph_node
*node
= cgraph_get_node (current_function_decl
);
1882 struct cgraph_edge
*edge
;
1883 unsigned int todo
= 0;
1885 bool inlined
= false;
1890 /* Do nothing if datastructures for ipa-inliner are already computed. This
1891 happens when some pass decides to construct new function and
1892 cgraph_add_new_function calls lowering passes and early optimization on
1893 it. This may confuse ourself when early inliner decide to inline call to
1894 function clone, because function clones don't have parameter list in
1895 ipa-prop matching their signature. */
1896 if (ipa_node_params_vector
)
1899 #ifdef ENABLE_CHECKING
1900 verify_cgraph_node (node
);
1903 /* Even when not optimizing or not inlining inline always-inline
1905 inlined
= inline_always_inline_functions (node
);
1909 || !flag_early_inlining
1910 /* Never inline regular functions into always-inline functions
1911 during incremental inlining. This sucks as functions calling
1912 always inline functions will get less optimized, but at the
1913 same time inlining of functions calling always inline
1914 function into an always inline function might introduce
1915 cycles of edges to be always inlined in the callgraph.
1917 We might want to be smarter and just avoid this type of inlining. */
1918 || DECL_DISREGARD_INLINE_LIMITS (node
->decl
))
1920 else if (lookup_attribute ("flatten",
1921 DECL_ATTRIBUTES (node
->decl
)) != NULL
)
1923 /* When the function is marked to be flattened, recursively inline
1927 "Flattening %s\n", cgraph_node_name (node
));
1928 flatten_function (node
, true);
1933 /* We iterate incremental inlining to get trivial cases of indirect
1935 while (iterations
< PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS
)
1936 && early_inline_small_functions (node
))
1938 timevar_push (TV_INTEGRATION
);
1939 todo
|= optimize_inline_calls (current_function_decl
);
1941 /* Technically we ought to recompute inline parameters so the new
1942 iteration of early inliner works as expected. We however have
1943 values approximately right and thus we only need to update edge
1944 info that might be cleared out for newly discovered edges. */
1945 for (edge
= node
->callees
; edge
; edge
= edge
->next_callee
)
1947 struct inline_edge_summary
*es
= inline_edge_summary (edge
);
1949 = estimate_num_insns (edge
->call_stmt
, &eni_size_weights
);
1951 = estimate_num_insns (edge
->call_stmt
, &eni_time_weights
);
1952 edge
->call_stmt_cannot_inline_p
1953 = gimple_call_cannot_inline_p (edge
->call_stmt
);
1955 timevar_pop (TV_INTEGRATION
);
1960 fprintf (dump_file
, "Iterations: %i\n", iterations
);
1965 timevar_push (TV_INTEGRATION
);
1966 todo
|= optimize_inline_calls (current_function_decl
);
1967 timevar_pop (TV_INTEGRATION
);
1970 cfun
->always_inline_functions_inlined
= true;
1975 struct gimple_opt_pass pass_early_inline
=
1979 "einline", /* name */
1981 early_inliner
, /* execute */
1984 0, /* static_pass_number */
1985 TV_INLINE_HEURISTICS
, /* tv_id */
1986 PROP_ssa
, /* properties_required */
1987 0, /* properties_provided */
1988 0, /* properties_destroyed */
1989 0, /* todo_flags_start */
1990 0 /* todo_flags_finish */
1995 /* When to run IPA inlining. Inlining of always-inline functions
1996 happens during early inlining.
1998 Enable inlining unconditoinally at -flto. We need size estimates to
1999 drive partitioning. */
2002 gate_ipa_inline (void)
2004 return optimize
|| flag_lto
|| flag_wpa
;
2007 struct ipa_opt_pass_d pass_ipa_inline
=
2011 "inline", /* name */
2012 gate_ipa_inline
, /* gate */
2013 ipa_inline
, /* execute */
2016 0, /* static_pass_number */
2017 TV_INLINE_HEURISTICS
, /* tv_id */
2018 0, /* properties_required */
2019 0, /* properties_provided */
2020 0, /* properties_destroyed */
2021 TODO_remove_functions
, /* todo_flags_finish */
2023 | TODO_remove_functions
| TODO_ggc_collect
/* todo_flags_finish */
2025 inline_generate_summary
, /* generate_summary */
2026 inline_write_summary
, /* write_summary */
2027 inline_read_summary
, /* read_summary */
2028 NULL
, /* write_optimization_summary */
2029 NULL
, /* read_optimization_summary */
2030 NULL
, /* stmt_fixup */
2032 inline_transform
, /* function_transform */
2033 NULL
, /* variable_transform */