1 /* Function splitting pass
2 Copyright (C) 2010, 2011, 2012
3 Free Software Foundation, Inc.
4 Contributed by Jan Hubicka <jh@suse.cz>
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 /* The purpose of this pass is to split function bodies to improve
23 inlining. I.e. for function of the form:
48 When func becomes inlinable and when cheap_test is often true, inlining func,
49 but not fund.part leads to performance improvement similar as inlining
50 original func while the code size growth is smaller.
52 The pass is organized in three stages:
53 1) Collect local info about basic block into BB_INFO structure and
54 compute function body estimated size and time.
55 2) Via DFS walk find all possible basic blocks where we can split
57 3) If split point is found, split at the specified BB by creating a clone
58 and updating function to call it.
60 The decisions what functions to split are in execute_split_functions
63 There are several possible future improvements for this pass including:
65 1) Splitting to break up large functions
66 2) Splitting to reduce stack frame usage
67 3) Allow split part of function to use values computed in the header part.
68 The values needs to be passed to split function, perhaps via same
69 interface as for nested functions or as argument.
70 4) Support for simple rematerialization. I.e. when split part use
71 value computed in header from function parameter in very cheap way, we
72 can just recompute it.
73 5) Support splitting of nested functions.
74 6) Support non-SSA arguments.
75 7) There is nothing preventing us from producing multiple parts of single function
76 when needed or splitting also the parts. */
80 #include "coretypes.h"
85 #include "tree-flow.h"
86 #include "tree-pass.h"
89 #include "diagnostic.h"
90 #include "tree-dump.h"
91 #include "tree-inline.h"
94 #include "gimple-pretty-print.h"
95 #include "ipa-inline.h"
97 /* Per basic block info. */
105 DEF_VEC_ALLOC_O(bb_info
,heap
);
107 static VEC(bb_info
, heap
) *bb_info_vec
;
109 /* Description of split point. */
113 /* Size of the partitions. */
114 unsigned int header_time
, header_size
, split_time
, split_size
;
116 /* SSA names that need to be passed into spit function. */
117 bitmap ssa_names_to_pass
;
119 /* Basic block where we split (that will become entry point of new function. */
120 basic_block entry_bb
;
122 /* Basic blocks we are splitting away. */
125 /* True when return value is computed on split part and thus it needs
127 bool split_part_set_retval
;
130 /* Best split point found. */
132 struct split_point best_split_point
;
134 /* Set of basic blocks that are not allowed to dominate a split point. */
136 static bitmap forbidden_dominators
;
138 static tree
find_retval (basic_block return_bb
);
140 /* Callback for walk_stmt_load_store_addr_ops. If T is non-SSA automatic
141 variable, check it if it is present in bitmap passed via DATA. */
144 test_nonssa_use (gimple stmt ATTRIBUTE_UNUSED
, tree t
, void *data
)
146 t
= get_base_address (t
);
148 if (!t
|| is_gimple_reg (t
))
151 if (TREE_CODE (t
) == PARM_DECL
152 || (TREE_CODE (t
) == VAR_DECL
153 && auto_var_in_fn_p (t
, current_function_decl
))
154 || TREE_CODE (t
) == RESULT_DECL
155 || TREE_CODE (t
) == LABEL_DECL
)
156 return bitmap_bit_p ((bitmap
)data
, DECL_UID (t
));
158 /* For DECL_BY_REFERENCE, the return value is actually a pointer. We want
159 to pretend that the value pointed to is actual result decl. */
160 if ((TREE_CODE (t
) == MEM_REF
|| INDIRECT_REF_P (t
))
161 && TREE_CODE (TREE_OPERAND (t
, 0)) == SSA_NAME
162 && TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (t
, 0))) == RESULT_DECL
163 && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
165 bitmap_bit_p ((bitmap
)data
,
166 DECL_UID (DECL_RESULT (current_function_decl
)));
171 /* Dump split point CURRENT. */
174 dump_split_point (FILE * file
, struct split_point
*current
)
177 "Split point at BB %i\n"
178 " header time: %i header size: %i\n"
179 " split time: %i split size: %i\n bbs: ",
180 current
->entry_bb
->index
, current
->header_time
,
181 current
->header_size
, current
->split_time
, current
->split_size
);
182 dump_bitmap (file
, current
->split_bbs
);
183 fprintf (file
, " SSA names to pass: ");
184 dump_bitmap (file
, current
->ssa_names_to_pass
);
187 /* Look for all BBs in header that might lead to the split part and verify
188 that they are not defining any non-SSA var used by the split part.
189 Parameters are the same as for consider_split. */
192 verify_non_ssa_vars (struct split_point
*current
, bitmap non_ssa_vars
,
193 basic_block return_bb
)
195 bitmap seen
= BITMAP_ALLOC (NULL
);
196 VEC (basic_block
,heap
) *worklist
= NULL
;
201 FOR_EACH_EDGE (e
, ei
, current
->entry_bb
->preds
)
202 if (e
->src
!= ENTRY_BLOCK_PTR
203 && !bitmap_bit_p (current
->split_bbs
, e
->src
->index
))
205 VEC_safe_push (basic_block
, heap
, worklist
, e
->src
);
206 bitmap_set_bit (seen
, e
->src
->index
);
209 while (!VEC_empty (basic_block
, worklist
))
211 gimple_stmt_iterator bsi
;
212 basic_block bb
= VEC_pop (basic_block
, worklist
);
214 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
215 if (e
->src
!= ENTRY_BLOCK_PTR
216 && bitmap_set_bit (seen
, e
->src
->index
))
218 gcc_checking_assert (!bitmap_bit_p (current
->split_bbs
,
220 VEC_safe_push (basic_block
, heap
, worklist
, e
->src
);
222 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
224 gimple stmt
= gsi_stmt (bsi
);
225 if (is_gimple_debug (stmt
))
227 if (walk_stmt_load_store_addr_ops
228 (stmt
, non_ssa_vars
, test_nonssa_use
, test_nonssa_use
,
234 if (gimple_code (stmt
) == GIMPLE_LABEL
235 && test_nonssa_use (stmt
, gimple_label_label (stmt
),
242 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
244 if (walk_stmt_load_store_addr_ops
245 (gsi_stmt (bsi
), non_ssa_vars
, test_nonssa_use
, test_nonssa_use
,
252 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
254 if (e
->dest
!= return_bb
)
256 for (bsi
= gsi_start_phis (return_bb
); !gsi_end_p (bsi
);
259 gimple stmt
= gsi_stmt (bsi
);
260 tree op
= gimple_phi_arg_def (stmt
, e
->dest_idx
);
262 if (!is_gimple_reg (gimple_phi_result (stmt
)))
264 if (TREE_CODE (op
) != SSA_NAME
265 && test_nonssa_use (stmt
, op
, non_ssa_vars
))
275 VEC_free (basic_block
, heap
, worklist
);
279 /* If STMT is a call, check the callee against a list of forbidden
280 predicate functions. If a match is found, look for uses of the
281 call result in condition statements that compare against zero.
282 For each such use, find the block targeted by the condition
283 statement for the nonzero result, and set the bit for this block
284 in the forbidden dominators bitmap. The purpose of this is to avoid
285 selecting a split point where we are likely to lose the chance
286 to optimize away an unused function call. */
289 check_forbidden_calls (gimple stmt
)
291 imm_use_iterator use_iter
;
295 /* At the moment, __builtin_constant_p is the only forbidden
296 predicate function call (see PR49642). */
297 if (!gimple_call_builtin_p (stmt
, BUILT_IN_CONSTANT_P
))
300 lhs
= gimple_call_lhs (stmt
);
302 if (!lhs
|| TREE_CODE (lhs
) != SSA_NAME
)
305 FOR_EACH_IMM_USE_FAST (use_p
, use_iter
, lhs
)
308 basic_block use_bb
, forbidden_bb
;
310 edge true_edge
, false_edge
;
311 gimple use_stmt
= USE_STMT (use_p
);
313 if (gimple_code (use_stmt
) != GIMPLE_COND
)
316 /* Assuming canonical form for GIMPLE_COND here, with constant
317 in second position. */
318 op1
= gimple_cond_rhs (use_stmt
);
319 code
= gimple_cond_code (use_stmt
);
320 use_bb
= gimple_bb (use_stmt
);
322 extract_true_false_edges_from_block (use_bb
, &true_edge
, &false_edge
);
324 /* We're only interested in comparisons that distinguish
325 unambiguously from zero. */
326 if (!integer_zerop (op1
) || code
== LE_EXPR
|| code
== GE_EXPR
)
330 forbidden_bb
= false_edge
->dest
;
332 forbidden_bb
= true_edge
->dest
;
334 bitmap_set_bit (forbidden_dominators
, forbidden_bb
->index
);
338 /* If BB is dominated by any block in the forbidden dominators set,
339 return TRUE; else FALSE. */
342 dominated_by_forbidden (basic_block bb
)
347 EXECUTE_IF_SET_IN_BITMAP (forbidden_dominators
, 1, dom_bb
, bi
)
349 if (dominated_by_p (CDI_DOMINATORS
, bb
, BASIC_BLOCK (dom_bb
)))
356 /* We found an split_point CURRENT. NON_SSA_VARS is bitmap of all non ssa
357 variables used and RETURN_BB is return basic block.
358 See if we can split function here. */
361 consider_split (struct split_point
*current
, bitmap non_ssa_vars
,
362 basic_block return_bb
)
365 unsigned int num_args
= 0;
366 unsigned int call_overhead
;
369 gimple_stmt_iterator bsi
;
371 int incoming_freq
= 0;
374 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
375 dump_split_point (dump_file
, current
);
377 FOR_EACH_EDGE (e
, ei
, current
->entry_bb
->preds
)
378 if (!bitmap_bit_p (current
->split_bbs
, e
->src
->index
))
379 incoming_freq
+= EDGE_FREQUENCY (e
);
381 /* Do not split when we would end up calling function anyway. */
383 >= (ENTRY_BLOCK_PTR
->frequency
384 * PARAM_VALUE (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY
) / 100))
386 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
388 " Refused: incoming frequency is too large.\n");
392 if (!current
->header_size
)
394 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
395 fprintf (dump_file
, " Refused: header empty\n");
399 /* Verify that PHI args on entry are either virtual or all their operands
400 incoming from header are the same. */
401 for (bsi
= gsi_start_phis (current
->entry_bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
403 gimple stmt
= gsi_stmt (bsi
);
406 if (!is_gimple_reg (gimple_phi_result (stmt
)))
408 for (i
= 0; i
< gimple_phi_num_args (stmt
); i
++)
410 edge e
= gimple_phi_arg_edge (stmt
, i
);
411 if (!bitmap_bit_p (current
->split_bbs
, e
->src
->index
))
413 tree edge_val
= gimple_phi_arg_def (stmt
, i
);
414 if (val
&& edge_val
!= val
)
416 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
418 " Refused: entry BB has PHI with multiple variants\n");
427 /* See what argument we will pass to the split function and compute
429 call_overhead
= eni_size_weights
.call_cost
;
430 for (parm
= DECL_ARGUMENTS (current_function_decl
); parm
;
431 parm
= DECL_CHAIN (parm
))
433 if (!is_gimple_reg (parm
))
435 if (bitmap_bit_p (non_ssa_vars
, DECL_UID (parm
)))
437 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
439 " Refused: need to pass non-ssa param values\n");
443 else if (gimple_default_def (cfun
, parm
)
444 && bitmap_bit_p (current
->ssa_names_to_pass
,
445 SSA_NAME_VERSION (gimple_default_def
448 if (!VOID_TYPE_P (TREE_TYPE (parm
)))
449 call_overhead
+= estimate_move_cost (TREE_TYPE (parm
));
453 if (!VOID_TYPE_P (TREE_TYPE (current_function_decl
)))
454 call_overhead
+= estimate_move_cost (TREE_TYPE (current_function_decl
));
456 if (current
->split_size
<= call_overhead
)
458 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
460 " Refused: split size is smaller than call overhead\n");
463 if (current
->header_size
+ call_overhead
464 >= (unsigned int)(DECL_DECLARED_INLINE_P (current_function_decl
)
465 ? MAX_INLINE_INSNS_SINGLE
466 : MAX_INLINE_INSNS_AUTO
))
468 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
470 " Refused: header size is too large for inline candidate\n");
474 /* FIXME: we currently can pass only SSA function parameters to the split
475 arguments. Once parm_adjustment infrastructure is supported by cloning,
476 we can pass more than that. */
477 if (num_args
!= bitmap_count_bits (current
->ssa_names_to_pass
))
480 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
482 " Refused: need to pass non-param values\n");
486 /* When there are non-ssa vars used in the split region, see if they
487 are used in the header region. If so, reject the split.
488 FIXME: we can use nested function support to access both. */
489 if (!bitmap_empty_p (non_ssa_vars
)
490 && !verify_non_ssa_vars (current
, non_ssa_vars
, return_bb
))
492 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
494 " Refused: split part has non-ssa uses\n");
498 /* If the split point is dominated by a forbidden block, reject
500 if (!bitmap_empty_p (forbidden_dominators
)
501 && dominated_by_forbidden (current
->entry_bb
))
503 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
505 " Refused: split point dominated by forbidden block\n");
509 /* See if retval used by return bb is computed by header or split part.
510 When it is computed by split part, we need to produce return statement
511 in the split part and add code to header to pass it around.
513 This is bit tricky to test:
514 1) When there is no return_bb or no return value, we always pass
516 2) Invariants are always computed by caller.
517 3) For SSA we need to look if defining statement is in header or split part
518 4) For non-SSA we need to look where the var is computed. */
519 retval
= find_retval (return_bb
);
521 current
->split_part_set_retval
= true;
522 else if (is_gimple_min_invariant (retval
))
523 current
->split_part_set_retval
= false;
524 /* Special case is value returned by reference we record as if it was non-ssa
525 set to result_decl. */
526 else if (TREE_CODE (retval
) == SSA_NAME
527 && TREE_CODE (SSA_NAME_VAR (retval
)) == RESULT_DECL
528 && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
529 current
->split_part_set_retval
530 = bitmap_bit_p (non_ssa_vars
, DECL_UID (SSA_NAME_VAR (retval
)));
531 else if (TREE_CODE (retval
) == SSA_NAME
)
532 current
->split_part_set_retval
533 = (!SSA_NAME_IS_DEFAULT_DEF (retval
)
534 && (bitmap_bit_p (current
->split_bbs
,
535 gimple_bb (SSA_NAME_DEF_STMT (retval
))->index
)
536 || gimple_bb (SSA_NAME_DEF_STMT (retval
)) == return_bb
));
537 else if (TREE_CODE (retval
) == PARM_DECL
)
538 current
->split_part_set_retval
= false;
539 else if (TREE_CODE (retval
) == VAR_DECL
540 || TREE_CODE (retval
) == RESULT_DECL
)
541 current
->split_part_set_retval
542 = bitmap_bit_p (non_ssa_vars
, DECL_UID (retval
));
544 current
->split_part_set_retval
= true;
546 /* split_function fixes up at most one PHI non-virtual PHI node in return_bb,
547 for the return value. If there are other PHIs, give up. */
548 if (return_bb
!= EXIT_BLOCK_PTR
)
550 gimple_stmt_iterator psi
;
552 for (psi
= gsi_start_phis (return_bb
); !gsi_end_p (psi
); gsi_next (&psi
))
553 if (is_gimple_reg (gimple_phi_result (gsi_stmt (psi
)))
555 && current
->split_part_set_retval
556 && TREE_CODE (retval
) == SSA_NAME
557 && !DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
))
558 && SSA_NAME_DEF_STMT (retval
) == gsi_stmt (psi
)))
560 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
562 " Refused: return bb has extra PHIs\n");
567 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
568 fprintf (dump_file
, " Accepted!\n");
570 /* At the moment chose split point with lowest frequency and that leaves
571 out smallest size of header.
572 In future we might re-consider this heuristics. */
573 if (!best_split_point
.split_bbs
574 || best_split_point
.entry_bb
->frequency
> current
->entry_bb
->frequency
575 || (best_split_point
.entry_bb
->frequency
== current
->entry_bb
->frequency
576 && best_split_point
.split_size
< current
->split_size
))
579 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
580 fprintf (dump_file
, " New best split point!\n");
581 if (best_split_point
.ssa_names_to_pass
)
583 BITMAP_FREE (best_split_point
.ssa_names_to_pass
);
584 BITMAP_FREE (best_split_point
.split_bbs
);
586 best_split_point
= *current
;
587 best_split_point
.ssa_names_to_pass
= BITMAP_ALLOC (NULL
);
588 bitmap_copy (best_split_point
.ssa_names_to_pass
,
589 current
->ssa_names_to_pass
);
590 best_split_point
.split_bbs
= BITMAP_ALLOC (NULL
);
591 bitmap_copy (best_split_point
.split_bbs
, current
->split_bbs
);
595 /* Return basic block containing RETURN statement. We allow basic blocks
599 but return_bb can not be more complex than this.
600 If nothing is found, return EXIT_BLOCK_PTR.
602 When there are multiple RETURN statement, chose one with return value,
603 since that one is more likely shared by multiple code paths.
605 Return BB is special, because for function splitting it is the only
606 basic block that is duplicated in between header and split part of the
609 TODO: We might support multiple return blocks. */
612 find_return_bb (void)
615 basic_block return_bb
= EXIT_BLOCK_PTR
;
616 gimple_stmt_iterator bsi
;
617 bool found_return
= false;
618 tree retval
= NULL_TREE
;
620 if (!single_pred_p (EXIT_BLOCK_PTR
))
623 e
= single_pred_edge (EXIT_BLOCK_PTR
);
624 for (bsi
= gsi_last_bb (e
->src
); !gsi_end_p (bsi
); gsi_prev (&bsi
))
626 gimple stmt
= gsi_stmt (bsi
);
627 if (gimple_code (stmt
) == GIMPLE_LABEL
628 || is_gimple_debug (stmt
)
629 || gimple_clobber_p (stmt
))
631 else if (gimple_code (stmt
) == GIMPLE_ASSIGN
633 && gimple_assign_single_p (stmt
)
634 && (auto_var_in_fn_p (gimple_assign_rhs1 (stmt
),
635 current_function_decl
)
636 || is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
637 && retval
== gimple_assign_lhs (stmt
))
639 else if (gimple_code (stmt
) == GIMPLE_RETURN
)
642 retval
= gimple_return_retval (stmt
);
647 if (gsi_end_p (bsi
) && found_return
)
653 /* Given return basic block RETURN_BB, see where return value is really
656 find_retval (basic_block return_bb
)
658 gimple_stmt_iterator bsi
;
659 for (bsi
= gsi_start_bb (return_bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
660 if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_RETURN
)
661 return gimple_return_retval (gsi_stmt (bsi
));
662 else if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_ASSIGN
663 && !gimple_clobber_p (gsi_stmt (bsi
)))
664 return gimple_assign_rhs1 (gsi_stmt (bsi
));
668 /* Callback for walk_stmt_load_store_addr_ops. If T is non-SSA automatic
669 variable, mark it as used in bitmap passed via DATA.
670 Return true when access to T prevents splitting the function. */
673 mark_nonssa_use (gimple stmt ATTRIBUTE_UNUSED
, tree t
, void *data
)
675 t
= get_base_address (t
);
677 if (!t
|| is_gimple_reg (t
))
680 /* At present we can't pass non-SSA arguments to split function.
681 FIXME: this can be relaxed by passing references to arguments. */
682 if (TREE_CODE (t
) == PARM_DECL
)
684 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
686 "Cannot split: use of non-ssa function parameter.\n");
690 if ((TREE_CODE (t
) == VAR_DECL
691 && auto_var_in_fn_p (t
, current_function_decl
))
692 || TREE_CODE (t
) == RESULT_DECL
693 || TREE_CODE (t
) == LABEL_DECL
)
694 bitmap_set_bit ((bitmap
)data
, DECL_UID (t
));
696 /* For DECL_BY_REFERENCE, the return value is actually a pointer. We want
697 to pretend that the value pointed to is actual result decl. */
698 if ((TREE_CODE (t
) == MEM_REF
|| INDIRECT_REF_P (t
))
699 && TREE_CODE (TREE_OPERAND (t
, 0)) == SSA_NAME
700 && TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (t
, 0))) == RESULT_DECL
701 && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
703 bitmap_bit_p ((bitmap
)data
,
704 DECL_UID (DECL_RESULT (current_function_decl
)));
709 /* Compute local properties of basic block BB we collect when looking for
710 split points. We look for ssa defs and store them in SET_SSA_NAMES,
711 for ssa uses and store them in USED_SSA_NAMES and for any non-SSA automatic
712 vars stored in NON_SSA_VARS.
714 When BB has edge to RETURN_BB, collect uses in RETURN_BB too.
716 Return false when BB contains something that prevents it from being put into
720 visit_bb (basic_block bb
, basic_block return_bb
,
721 bitmap set_ssa_names
, bitmap used_ssa_names
,
724 gimple_stmt_iterator bsi
;
727 bool can_split
= true;
729 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
731 gimple stmt
= gsi_stmt (bsi
);
736 if (is_gimple_debug (stmt
))
739 if (gimple_clobber_p (stmt
))
742 /* FIXME: We can split regions containing EH. We can not however
743 split RESX, EH_DISPATCH and EH_POINTER referring to same region
744 into different partitions. This would require tracking of
745 EH regions and checking in consider_split_point if they
746 are not used elsewhere. */
747 if (gimple_code (stmt
) == GIMPLE_RESX
)
749 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
750 fprintf (dump_file
, "Cannot split: resx.\n");
753 if (gimple_code (stmt
) == GIMPLE_EH_DISPATCH
)
755 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
756 fprintf (dump_file
, "Cannot split: eh dispatch.\n");
760 /* Check builtins that prevent splitting. */
761 if (gimple_code (stmt
) == GIMPLE_CALL
762 && (decl
= gimple_call_fndecl (stmt
)) != NULL_TREE
763 && DECL_BUILT_IN (decl
)
764 && DECL_BUILT_IN_CLASS (decl
) == BUILT_IN_NORMAL
)
765 switch (DECL_FUNCTION_CODE (decl
))
767 /* FIXME: once we will allow passing non-parm values to split part,
768 we need to be sure to handle correct builtin_stack_save and
769 builtin_stack_restore. At the moment we are safe; there is no
770 way to store builtin_stack_save result in non-SSA variable
771 since all calls to those are compiler generated. */
773 case BUILT_IN_APPLY_ARGS
:
774 case BUILT_IN_VA_START
:
775 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
777 "Cannot split: builtin_apply and va_start.\n");
780 case BUILT_IN_EH_POINTER
:
781 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
782 fprintf (dump_file
, "Cannot split: builtin_eh_pointer.\n");
789 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_DEF
)
790 bitmap_set_bit (set_ssa_names
, SSA_NAME_VERSION (op
));
791 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
792 bitmap_set_bit (used_ssa_names
, SSA_NAME_VERSION (op
));
793 can_split
&= !walk_stmt_load_store_addr_ops (stmt
, non_ssa_vars
,
798 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
800 gimple stmt
= gsi_stmt (bsi
);
803 if (is_gimple_debug (stmt
))
805 if (!is_gimple_reg (gimple_phi_result (stmt
)))
807 bitmap_set_bit (set_ssa_names
,
808 SSA_NAME_VERSION (gimple_phi_result (stmt
)));
809 for (i
= 0; i
< gimple_phi_num_args (stmt
); i
++)
811 tree op
= gimple_phi_arg_def (stmt
, i
);
812 if (TREE_CODE (op
) == SSA_NAME
)
813 bitmap_set_bit (used_ssa_names
, SSA_NAME_VERSION (op
));
815 can_split
&= !walk_stmt_load_store_addr_ops (stmt
, non_ssa_vars
,
820 /* Record also uses coming from PHI operand in return BB. */
821 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
822 if (e
->dest
== return_bb
)
824 for (bsi
= gsi_start_phis (return_bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
826 gimple stmt
= gsi_stmt (bsi
);
827 tree op
= gimple_phi_arg_def (stmt
, e
->dest_idx
);
829 if (is_gimple_debug (stmt
))
831 if (!is_gimple_reg (gimple_phi_result (stmt
)))
833 if (TREE_CODE (op
) == SSA_NAME
)
834 bitmap_set_bit (used_ssa_names
, SSA_NAME_VERSION (op
));
836 can_split
&= !mark_nonssa_use (stmt
, op
, non_ssa_vars
);
842 /* Stack entry for recursive DFS walk in find_split_point. */
846 /* Basic block we are examining. */
849 /* SSA names set and used by the BB and all BBs reachable
850 from it via DFS walk. */
851 bitmap set_ssa_names
, used_ssa_names
;
854 /* All BBS visited from this BB via DFS walk. */
857 /* Last examined edge in DFS walk. Since we walk unoriented graph,
858 the value is up to sum of incoming and outgoing edges of BB. */
859 unsigned int edge_num
;
861 /* Stack entry index of earliest BB reachable from current BB
862 or any BB visited later in DFS walk. */
865 /* Overall time and size of all BBs reached from this BB in DFS walk. */
866 int overall_time
, overall_size
;
868 /* When false we can not split on this BB. */
871 DEF_VEC_O(stack_entry
);
872 DEF_VEC_ALLOC_O(stack_entry
,heap
);
875 /* Find all articulations and call consider_split on them.
876 OVERALL_TIME and OVERALL_SIZE is time and size of the function.
878 We perform basic algorithm for finding an articulation in a graph
879 created from CFG by considering it to be an unoriented graph.
881 The articulation is discovered via DFS walk. We collect earliest
882 basic block on stack that is reachable via backward edge. Articulation
883 is any basic block such that there is no backward edge bypassing it.
884 To reduce stack usage we maintain heap allocated stack in STACK vector.
885 AUX pointer of BB is set to index it appears in the stack or -1 once
886 it is visited and popped off the stack.
888 The algorithm finds articulation after visiting the whole component
889 reachable by it. This makes it convenient to collect information about
890 the component used by consider_split. */
893 find_split_points (int overall_time
, int overall_size
)
896 VEC(stack_entry
, heap
) *stack
= NULL
;
898 basic_block return_bb
= find_return_bb ();
899 struct split_point current
;
901 current
.header_time
= overall_time
;
902 current
.header_size
= overall_size
;
903 current
.split_time
= 0;
904 current
.split_size
= 0;
905 current
.ssa_names_to_pass
= BITMAP_ALLOC (NULL
);
907 first
.bb
= ENTRY_BLOCK_PTR
;
909 first
.overall_time
= 0;
910 first
.overall_size
= 0;
911 first
.earliest
= INT_MAX
;
912 first
.set_ssa_names
= 0;
913 first
.used_ssa_names
= 0;
914 first
.bbs_visited
= 0;
915 VEC_safe_push (stack_entry
, heap
, stack
, &first
);
916 ENTRY_BLOCK_PTR
->aux
= (void *)(intptr_t)-1;
918 while (!VEC_empty (stack_entry
, stack
))
920 stack_entry
*entry
= VEC_last (stack_entry
, stack
);
922 /* We are walking an acyclic graph, so edge_num counts
923 succ and pred edges together. However when considering
924 articulation, we want to have processed everything reachable
925 from articulation but nothing that reaches into it. */
926 if (entry
->edge_num
== EDGE_COUNT (entry
->bb
->succs
)
927 && entry
->bb
!= ENTRY_BLOCK_PTR
)
929 int pos
= VEC_length (stack_entry
, stack
);
930 entry
->can_split
&= visit_bb (entry
->bb
, return_bb
,
931 entry
->set_ssa_names
,
932 entry
->used_ssa_names
,
933 entry
->non_ssa_vars
);
934 if (pos
<= entry
->earliest
&& !entry
->can_split
935 && dump_file
&& (dump_flags
& TDF_DETAILS
))
937 "found articulation at bb %i but can not split\n",
939 if (pos
<= entry
->earliest
&& entry
->can_split
)
941 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
942 fprintf (dump_file
, "found articulation at bb %i\n",
944 current
.entry_bb
= entry
->bb
;
945 current
.ssa_names_to_pass
= BITMAP_ALLOC (NULL
);
946 bitmap_and_compl (current
.ssa_names_to_pass
,
947 entry
->used_ssa_names
, entry
->set_ssa_names
);
948 current
.header_time
= overall_time
- entry
->overall_time
;
949 current
.header_size
= overall_size
- entry
->overall_size
;
950 current
.split_time
= entry
->overall_time
;
951 current
.split_size
= entry
->overall_size
;
952 current
.split_bbs
= entry
->bbs_visited
;
953 consider_split (¤t
, entry
->non_ssa_vars
, return_bb
);
954 BITMAP_FREE (current
.ssa_names_to_pass
);
957 /* Do actual DFS walk. */
959 < (EDGE_COUNT (entry
->bb
->succs
)
960 + EDGE_COUNT (entry
->bb
->preds
)))
964 if (entry
->edge_num
< EDGE_COUNT (entry
->bb
->succs
))
966 e
= EDGE_SUCC (entry
->bb
, entry
->edge_num
);
971 e
= EDGE_PRED (entry
->bb
, entry
->edge_num
972 - EDGE_COUNT (entry
->bb
->succs
));
978 /* New BB to visit, push it to the stack. */
979 if (dest
!= return_bb
&& dest
!= EXIT_BLOCK_PTR
982 stack_entry new_entry
;
985 new_entry
.edge_num
= 0;
986 new_entry
.overall_time
987 = VEC_index (bb_info
, bb_info_vec
, dest
->index
)->time
;
988 new_entry
.overall_size
989 = VEC_index (bb_info
, bb_info_vec
, dest
->index
)->size
;
990 new_entry
.earliest
= INT_MAX
;
991 new_entry
.set_ssa_names
= BITMAP_ALLOC (NULL
);
992 new_entry
.used_ssa_names
= BITMAP_ALLOC (NULL
);
993 new_entry
.bbs_visited
= BITMAP_ALLOC (NULL
);
994 new_entry
.non_ssa_vars
= BITMAP_ALLOC (NULL
);
995 new_entry
.can_split
= true;
996 bitmap_set_bit (new_entry
.bbs_visited
, dest
->index
);
997 VEC_safe_push (stack_entry
, heap
, stack
, &new_entry
);
998 dest
->aux
= (void *)(intptr_t)VEC_length (stack_entry
, stack
);
1000 /* Back edge found, record the earliest point. */
1001 else if ((intptr_t)dest
->aux
> 0
1002 && (intptr_t)dest
->aux
< entry
->earliest
)
1003 entry
->earliest
= (intptr_t)dest
->aux
;
1005 /* We are done with examining the edges. Pop off the value from stack
1006 and merge stuff we accumulate during the walk. */
1007 else if (entry
->bb
!= ENTRY_BLOCK_PTR
)
1009 stack_entry
*prev
= VEC_index (stack_entry
, stack
,
1010 VEC_length (stack_entry
, stack
) - 2);
1012 entry
->bb
->aux
= (void *)(intptr_t)-1;
1013 prev
->can_split
&= entry
->can_split
;
1014 if (prev
->set_ssa_names
)
1016 bitmap_ior_into (prev
->set_ssa_names
, entry
->set_ssa_names
);
1017 bitmap_ior_into (prev
->used_ssa_names
, entry
->used_ssa_names
);
1018 bitmap_ior_into (prev
->bbs_visited
, entry
->bbs_visited
);
1019 bitmap_ior_into (prev
->non_ssa_vars
, entry
->non_ssa_vars
);
1021 if (prev
->earliest
> entry
->earliest
)
1022 prev
->earliest
= entry
->earliest
;
1023 prev
->overall_time
+= entry
->overall_time
;
1024 prev
->overall_size
+= entry
->overall_size
;
1025 BITMAP_FREE (entry
->set_ssa_names
);
1026 BITMAP_FREE (entry
->used_ssa_names
);
1027 BITMAP_FREE (entry
->bbs_visited
);
1028 BITMAP_FREE (entry
->non_ssa_vars
);
1029 VEC_pop (stack_entry
, stack
);
1032 VEC_pop (stack_entry
, stack
);
1034 ENTRY_BLOCK_PTR
->aux
= NULL
;
1037 VEC_free (stack_entry
, heap
, stack
);
1038 BITMAP_FREE (current
.ssa_names_to_pass
);
1041 /* Split function at SPLIT_POINT. */
1044 split_function (struct split_point
*split_point
)
1046 VEC (tree
, heap
) *args_to_pass
= NULL
;
1047 bitmap args_to_skip
;
1050 struct cgraph_node
*node
, *cur_node
= cgraph_get_node (current_function_decl
);
1051 basic_block return_bb
= find_return_bb ();
1052 basic_block call_bb
;
1053 gimple_stmt_iterator gsi
;
1057 tree retval
= NULL
, real_retval
= NULL
;
1058 bool split_part_return_p
= false;
1059 gimple last_stmt
= NULL
;
1065 fprintf (dump_file
, "\n\nSplitting function at:\n");
1066 dump_split_point (dump_file
, split_point
);
1069 if (cur_node
->local
.can_change_signature
)
1070 args_to_skip
= BITMAP_ALLOC (NULL
);
1072 args_to_skip
= NULL
;
1074 /* Collect the parameters of new function and args_to_skip bitmap. */
1075 for (parm
= DECL_ARGUMENTS (current_function_decl
);
1076 parm
; parm
= DECL_CHAIN (parm
), num
++)
1078 && (!is_gimple_reg (parm
)
1079 || !gimple_default_def (cfun
, parm
)
1080 || !bitmap_bit_p (split_point
->ssa_names_to_pass
,
1081 SSA_NAME_VERSION (gimple_default_def (cfun
,
1083 bitmap_set_bit (args_to_skip
, num
);
1086 /* This parm might not have been used up to now, but is going to be
1087 used, hence register it. */
1088 add_referenced_var (parm
);
1089 if (is_gimple_reg (parm
))
1091 arg
= gimple_default_def (cfun
, parm
);
1094 arg
= make_ssa_name (parm
, gimple_build_nop ());
1095 set_default_def (parm
, arg
);
1101 if (!useless_type_conversion_p (DECL_ARG_TYPE (parm
), TREE_TYPE (arg
)))
1102 arg
= fold_convert (DECL_ARG_TYPE (parm
), arg
);
1103 VEC_safe_push (tree
, heap
, args_to_pass
, arg
);
1106 /* See if the split function will return. */
1107 FOR_EACH_EDGE (e
, ei
, return_bb
->preds
)
1108 if (bitmap_bit_p (split_point
->split_bbs
, e
->src
->index
))
1111 split_part_return_p
= true;
1113 /* Add return block to what will become the split function.
1114 We do not return; no return block is needed. */
1115 if (!split_part_return_p
)
1117 /* We have no return block, so nothing is needed. */
1118 else if (return_bb
== EXIT_BLOCK_PTR
)
1120 /* When we do not want to return value, we need to construct
1121 new return block with empty return statement.
1122 FIXME: Once we are able to change return type, we should change function
1123 to return void instead of just outputting function with undefined return
1124 value. For structures this affects quality of codegen. */
1125 else if (!split_point
->split_part_set_retval
1126 && find_retval (return_bb
))
1128 bool redirected
= true;
1129 basic_block new_return_bb
= create_basic_block (NULL
, 0, return_bb
);
1130 gimple_stmt_iterator gsi
= gsi_start_bb (new_return_bb
);
1131 gsi_insert_after (&gsi
, gimple_build_return (NULL
), GSI_NEW_STMT
);
1135 FOR_EACH_EDGE (e
, ei
, return_bb
->preds
)
1136 if (bitmap_bit_p (split_point
->split_bbs
, e
->src
->index
))
1138 new_return_bb
->count
+= e
->count
;
1139 new_return_bb
->frequency
+= EDGE_FREQUENCY (e
);
1140 redirect_edge_and_branch (e
, new_return_bb
);
1145 e
= make_edge (new_return_bb
, EXIT_BLOCK_PTR
, 0);
1146 e
->probability
= REG_BR_PROB_BASE
;
1147 e
->count
= new_return_bb
->count
;
1148 bitmap_set_bit (split_point
->split_bbs
, new_return_bb
->index
);
1150 /* When we pass around the value, use existing return block. */
1152 bitmap_set_bit (split_point
->split_bbs
, return_bb
->index
);
1154 /* If RETURN_BB has virtual operand PHIs, they must be removed and the
1155 virtual operand marked for renaming as we change the CFG in a way that
1156 tree-inline is not able to compensate for.
1158 Note this can happen whether or not we have a return value. If we have
1159 a return value, then RETURN_BB may have PHIs for real operands too. */
1160 if (return_bb
!= EXIT_BLOCK_PTR
)
1163 for (gsi
= gsi_start_phis (return_bb
); !gsi_end_p (gsi
);)
1165 gimple stmt
= gsi_stmt (gsi
);
1166 if (is_gimple_reg (gimple_phi_result (stmt
)))
1171 mark_virtual_phi_result_for_renaming (stmt
);
1172 remove_phi_node (&gsi
, true);
1175 /* In reality we have to rename the reaching definition of the
1176 virtual operand at return_bb as we will eventually release it
1177 when we remove the code region we outlined.
1178 So we have to rename all immediate virtual uses of that region
1179 if we didn't see a PHI definition yet. */
1180 /* ??? In real reality we want to set the reaching vdef of the
1181 entry of the SESE region as the vuse of the call and the reaching
1182 vdef of the exit of the SESE region as the vdef of the call. */
1184 for (gsi
= gsi_start_bb (return_bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1186 gimple stmt
= gsi_stmt (gsi
);
1187 if (gimple_vuse (stmt
))
1189 gimple_set_vuse (stmt
, NULL_TREE
);
1192 if (gimple_vdef (stmt
))
1197 /* Now create the actual clone. */
1198 rebuild_cgraph_edges ();
1199 node
= cgraph_function_versioning (cur_node
, NULL
, NULL
, args_to_skip
,
1200 !split_part_return_p
,
1201 split_point
->split_bbs
,
1202 split_point
->entry_bb
, "part");
1203 /* For usual cloning it is enough to clear builtin only when signature
1204 changes. For partial inlining we however can not expect the part
1205 of builtin implementation to have same semantic as the whole. */
1206 if (DECL_BUILT_IN (node
->decl
))
1208 DECL_BUILT_IN_CLASS (node
->decl
) = NOT_BUILT_IN
;
1209 DECL_FUNCTION_CODE (node
->decl
) = (enum built_in_function
) 0;
1211 cgraph_node_remove_callees (cur_node
);
1212 if (!split_part_return_p
)
1213 TREE_THIS_VOLATILE (node
->decl
) = 1;
1215 dump_function_to_file (node
->decl
, dump_file
, dump_flags
);
1217 /* Create the basic block we place call into. It is the entry basic block
1218 split after last label. */
1219 call_bb
= split_point
->entry_bb
;
1220 for (gsi
= gsi_start_bb (call_bb
); !gsi_end_p (gsi
);)
1221 if (gimple_code (gsi_stmt (gsi
)) == GIMPLE_LABEL
)
1223 last_stmt
= gsi_stmt (gsi
);
1228 e
= split_block (split_point
->entry_bb
, last_stmt
);
1231 /* Produce the call statement. */
1232 gsi
= gsi_last_bb (call_bb
);
1233 FOR_EACH_VEC_ELT (tree
, args_to_pass
, i
, arg
)
1234 if (!is_gimple_val (arg
))
1236 arg
= force_gimple_operand_gsi (&gsi
, arg
, true, NULL_TREE
,
1237 false, GSI_CONTINUE_LINKING
);
1238 VEC_replace (tree
, args_to_pass
, i
, arg
);
1240 call
= gimple_build_call_vec (node
->decl
, args_to_pass
);
1241 gimple_set_block (call
, DECL_INITIAL (current_function_decl
));
1243 /* We avoid address being taken on any variable used by split part,
1244 so return slot optimization is always possible. Moreover this is
1245 required to make DECL_BY_REFERENCE work. */
1246 if (aggregate_value_p (DECL_RESULT (current_function_decl
),
1247 TREE_TYPE (current_function_decl
)))
1248 gimple_call_set_return_slot_opt (call
, true);
1250 /* Update return value. This is bit tricky. When we do not return,
1251 do nothing. When we return we might need to update return_bb
1252 or produce a new return statement. */
1253 if (!split_part_return_p
)
1254 gsi_insert_after (&gsi
, call
, GSI_NEW_STMT
);
1257 e
= make_edge (call_bb
, return_bb
,
1258 return_bb
== EXIT_BLOCK_PTR
? 0 : EDGE_FALLTHRU
);
1259 e
->count
= call_bb
->count
;
1260 e
->probability
= REG_BR_PROB_BASE
;
1262 /* If there is return basic block, see what value we need to store
1263 return value into and put call just before it. */
1264 if (return_bb
!= EXIT_BLOCK_PTR
)
1266 real_retval
= retval
= find_retval (return_bb
);
1268 if (real_retval
&& split_point
->split_part_set_retval
)
1270 gimple_stmt_iterator psi
;
1272 /* See if we need new SSA_NAME for the result.
1273 When DECL_BY_REFERENCE is true, retval is actually pointer to
1274 return value and it is constant in whole function. */
1275 if (TREE_CODE (retval
) == SSA_NAME
1276 && !DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
1278 retval
= make_ssa_name (SSA_NAME_VAR (retval
), call
);
1280 /* See if there is PHI defining return value. */
1281 for (psi
= gsi_start_phis (return_bb
);
1282 !gsi_end_p (psi
); gsi_next (&psi
))
1283 if (is_gimple_reg (gimple_phi_result (gsi_stmt (psi
))))
1286 /* When there is PHI, just update its value. */
1287 if (TREE_CODE (retval
) == SSA_NAME
1288 && !gsi_end_p (psi
))
1289 add_phi_arg (gsi_stmt (psi
), retval
, e
, UNKNOWN_LOCATION
);
1290 /* Otherwise update the return BB itself.
1291 find_return_bb allows at most one assignment to return value,
1292 so update first statement. */
1295 gimple_stmt_iterator bsi
;
1296 for (bsi
= gsi_start_bb (return_bb
); !gsi_end_p (bsi
);
1298 if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_RETURN
)
1300 gimple_return_set_retval (gsi_stmt (bsi
), retval
);
1303 else if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_ASSIGN
)
1305 gimple_assign_set_rhs1 (gsi_stmt (bsi
), retval
);
1308 update_stmt (gsi_stmt (bsi
));
1311 if (DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
1313 gimple_call_set_lhs (call
, build_simple_mem_ref (retval
));
1314 gsi_insert_after (&gsi
, call
, GSI_NEW_STMT
);
1319 restype
= TREE_TYPE (DECL_RESULT (current_function_decl
));
1320 gsi_insert_after (&gsi
, call
, GSI_NEW_STMT
);
1321 if (!useless_type_conversion_p (TREE_TYPE (retval
), restype
))
1324 tree tem
= create_tmp_reg (restype
, NULL
);
1325 tem
= make_ssa_name (tem
, call
);
1326 cpy
= gimple_build_assign_with_ops (NOP_EXPR
, retval
,
1328 gsi_insert_after (&gsi
, cpy
, GSI_NEW_STMT
);
1331 gimple_call_set_lhs (call
, retval
);
1336 gsi_insert_after (&gsi
, call
, GSI_NEW_STMT
);
1338 /* We don't use return block (there is either no return in function or
1339 multiple of them). So create new basic block with return statement.
1344 if (split_point
->split_part_set_retval
1345 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (current_function_decl
))))
1347 retval
= DECL_RESULT (current_function_decl
);
1349 /* We use temporary register to hold value when aggregate_value_p
1350 is false. Similarly for DECL_BY_REFERENCE we must avoid extra
1352 if (!aggregate_value_p (retval
, TREE_TYPE (current_function_decl
))
1353 && !DECL_BY_REFERENCE (retval
))
1354 retval
= create_tmp_reg (TREE_TYPE (retval
), NULL
);
1355 if (is_gimple_reg (retval
))
1357 /* When returning by reference, there is only one SSA name
1358 assigned to RESULT_DECL (that is pointer to return value).
1359 Look it up or create new one if it is missing. */
1360 if (DECL_BY_REFERENCE (retval
))
1363 if ((retval_name
= gimple_default_def (cfun
, retval
))
1365 retval
= retval_name
;
1368 retval_name
= make_ssa_name (retval
,
1369 gimple_build_nop ());
1370 set_default_def (retval
, retval_name
);
1371 retval
= retval_name
;
1374 /* Otherwise produce new SSA name for return value. */
1376 retval
= make_ssa_name (retval
, call
);
1378 if (DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
1379 gimple_call_set_lhs (call
, build_simple_mem_ref (retval
));
1381 gimple_call_set_lhs (call
, retval
);
1383 gsi_insert_after (&gsi
, call
, GSI_NEW_STMT
);
1384 ret
= gimple_build_return (retval
);
1385 gsi_insert_after (&gsi
, ret
, GSI_NEW_STMT
);
1388 free_dominance_info (CDI_DOMINATORS
);
1389 free_dominance_info (CDI_POST_DOMINATORS
);
1390 compute_inline_parameters (node
, true);
1393 /* Execute function splitting pass. */
1396 execute_split_functions (void)
1398 gimple_stmt_iterator bsi
;
1400 int overall_time
= 0, overall_size
= 0;
1402 struct cgraph_node
*node
= cgraph_get_node (current_function_decl
);
1404 if (flags_from_decl_or_type (current_function_decl
)
1405 & (ECF_NORETURN
|ECF_MALLOC
))
1408 fprintf (dump_file
, "Not splitting: noreturn/malloc function.\n");
1411 if (MAIN_NAME_P (DECL_NAME (current_function_decl
)))
1414 fprintf (dump_file
, "Not splitting: main function.\n");
1417 /* This can be relaxed; function might become inlinable after splitting
1418 away the uninlinable part. */
1419 if (!inline_summary (node
)->inlinable
)
1422 fprintf (dump_file
, "Not splitting: not inlinable.\n");
1425 if (DECL_DISREGARD_INLINE_LIMITS (node
->decl
))
1428 fprintf (dump_file
, "Not splitting: disregarding inline limits.\n");
1431 /* This can be relaxed; most of versioning tests actually prevents
1433 if (!tree_versionable_function_p (current_function_decl
))
1436 fprintf (dump_file
, "Not splitting: not versionable.\n");
1439 /* FIXME: we could support this. */
1440 if (DECL_STRUCT_FUNCTION (current_function_decl
)->static_chain_decl
)
1443 fprintf (dump_file
, "Not splitting: nested function.\n");
1447 /* See if it makes sense to try to split.
1448 It makes sense to split if we inline, that is if we have direct calls to
1449 handle or direct calls are possibly going to appear as result of indirect
1450 inlining or LTO. Also handle -fprofile-generate as LTO to allow non-LTO
1451 training for LTO -fprofile-use build.
1453 Note that we are not completely conservative about disqualifying functions
1454 called once. It is possible that the caller is called more then once and
1455 then inlining would still benefit. */
1456 if ((!node
->callers
|| !node
->callers
->next_caller
)
1457 && !node
->address_taken
1458 && (!flag_lto
|| !node
->local
.externally_visible
))
1461 fprintf (dump_file
, "Not splitting: not called directly "
1462 "or called once.\n");
1466 /* FIXME: We can actually split if splitting reduces call overhead. */
1467 if (!flag_inline_small_functions
1468 && !DECL_DECLARED_INLINE_P (current_function_decl
))
1471 fprintf (dump_file
, "Not splitting: not autoinlining and function"
1472 " is not inline.\n");
1476 /* Initialize bitmap to track forbidden calls. */
1477 forbidden_dominators
= BITMAP_ALLOC (NULL
);
1478 calculate_dominance_info (CDI_DOMINATORS
);
1480 /* Compute local info about basic blocks and determine function size/time. */
1481 VEC_safe_grow_cleared (bb_info
, heap
, bb_info_vec
, last_basic_block
+ 1);
1482 memset (&best_split_point
, 0, sizeof (best_split_point
));
1487 int freq
= compute_call_stmt_bb_frequency (current_function_decl
, bb
);
1489 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1490 fprintf (dump_file
, "Basic block %i\n", bb
->index
);
1492 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1494 int this_time
, this_size
;
1495 gimple stmt
= gsi_stmt (bsi
);
1497 this_size
= estimate_num_insns (stmt
, &eni_size_weights
);
1498 this_time
= estimate_num_insns (stmt
, &eni_time_weights
) * freq
;
1501 check_forbidden_calls (stmt
);
1503 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1505 fprintf (dump_file
, " freq:%6i size:%3i time:%3i ",
1506 freq
, this_size
, this_time
);
1507 print_gimple_stmt (dump_file
, stmt
, 0, 0);
1510 overall_time
+= time
;
1511 overall_size
+= size
;
1512 VEC_index (bb_info
, bb_info_vec
, bb
->index
)->time
= time
;
1513 VEC_index (bb_info
, bb_info_vec
, bb
->index
)->size
= size
;
1515 find_split_points (overall_time
, overall_size
);
1516 if (best_split_point
.split_bbs
)
1518 split_function (&best_split_point
);
1519 BITMAP_FREE (best_split_point
.ssa_names_to_pass
);
1520 BITMAP_FREE (best_split_point
.split_bbs
);
1521 todo
= TODO_update_ssa
| TODO_cleanup_cfg
;
1523 BITMAP_FREE (forbidden_dominators
);
1524 VEC_free (bb_info
, heap
, bb_info_vec
);
1529 /* Gate function splitting pass. When doing profile feedback, we want
1530 to execute the pass after profiling is read. So disable one in
1531 early optimization. */
1534 gate_split_functions (void)
1536 return (flag_partial_inlining
1537 && !profile_arc_flag
&& !flag_branch_probabilities
);
1540 struct gimple_opt_pass pass_split_functions
=
1544 "fnsplit", /* name */
1545 gate_split_functions
, /* gate */
1546 execute_split_functions
, /* execute */
1549 0, /* static_pass_number */
1550 TV_IPA_FNSPLIT
, /* tv_id */
1551 PROP_cfg
, /* properties_required */
1552 0, /* properties_provided */
1553 0, /* properties_destroyed */
1554 0, /* todo_flags_start */
1555 TODO_verify_all
/* todo_flags_finish */
1559 /* Gate feedback driven function splitting pass.
1560 We don't need to split when profiling at all, we are producing
1561 lousy code anyway. */
1564 gate_feedback_split_functions (void)
1566 return (flag_partial_inlining
1567 && flag_branch_probabilities
);
1570 /* Execute function splitting pass. */
1573 execute_feedback_split_functions (void)
1575 unsigned int retval
= execute_split_functions ();
1577 retval
|= TODO_rebuild_cgraph_edges
;
1581 struct gimple_opt_pass pass_feedback_split_functions
=
1585 "feedback_fnsplit", /* name */
1586 gate_feedback_split_functions
, /* gate */
1587 execute_feedback_split_functions
, /* execute */
1590 0, /* static_pass_number */
1591 TV_IPA_FNSPLIT
, /* tv_id */
1592 PROP_cfg
, /* properties_required */
1593 0, /* properties_provided */
1594 0, /* properties_destroyed */
1595 0, /* todo_flags_start */
1596 TODO_verify_all
/* todo_flags_finish */