1 /* Function splitting pass
2 Copyright (C) 2010-2014 Free Software Foundation, Inc.
3 Contributed by Jan Hubicka <jh@suse.cz>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* The purpose of this pass is to split function bodies to improve
22 inlining. I.e. for function of the form:
47 When func becomes inlinable and when cheap_test is often true, inlining func,
48 but not fund.part leads to performance improvement similar as inlining
49 original func while the code size growth is smaller.
51 The pass is organized in three stages:
52 1) Collect local info about basic block into BB_INFO structure and
53 compute function body estimated size and time.
54 2) Via DFS walk find all possible basic blocks where we can split
56 3) If split point is found, split at the specified BB by creating a clone
57 and updating function to call it.
59 The decisions what functions to split are in execute_split_functions
62 There are several possible future improvements for this pass including:
64 1) Splitting to break up large functions
65 2) Splitting to reduce stack frame usage
66 3) Allow split part of function to use values computed in the header part.
67 The values needs to be passed to split function, perhaps via same
68 interface as for nested functions or as argument.
69 4) Support for simple rematerialization. I.e. when split part use
70 value computed in header from function parameter in very cheap way, we
71 can just recompute it.
72 5) Support splitting of nested functions.
73 6) Support non-SSA arguments.
74 7) There is nothing preventing us from producing multiple parts of single function
75 when needed or splitting also the parts. */
79 #include "coretypes.h"
81 #include "basic-block.h"
82 #include "tree-ssa-alias.h"
83 #include "internal-fn.h"
84 #include "gimple-expr.h"
87 #include "stringpool.h"
91 #include "gimple-iterator.h"
92 #include "gimplify-me.h"
93 #include "gimple-walk.h"
96 #include "gimple-ssa.h"
98 #include "tree-phinodes.h"
99 #include "ssa-iterators.h"
100 #include "stringpool.h"
101 #include "tree-ssanames.h"
102 #include "tree-into-ssa.h"
103 #include "tree-dfa.h"
104 #include "tree-pass.h"
106 #include "diagnostic.h"
107 #include "tree-dump.h"
108 #include "tree-inline.h"
110 #include "gimple-pretty-print.h"
111 #include "ipa-inline.h"
114 /* Per basic block info. */
122 static vec
<bb_info
> bb_info_vec
;
124 /* Description of split point. */
128 /* Size of the partitions. */
129 unsigned int header_time
, header_size
, split_time
, split_size
;
131 /* SSA names that need to be passed into spit function. */
132 bitmap ssa_names_to_pass
;
134 /* Basic block where we split (that will become entry point of new function. */
135 basic_block entry_bb
;
137 /* Basic blocks we are splitting away. */
140 /* True when return value is computed on split part and thus it needs
142 bool split_part_set_retval
;
145 /* Best split point found. */
147 struct split_point best_split_point
;
149 /* Set of basic blocks that are not allowed to dominate a split point. */
151 static bitmap forbidden_dominators
;
153 static tree
find_retval (basic_block return_bb
);
155 /* Callback for walk_stmt_load_store_addr_ops. If T is non-SSA automatic
156 variable, check it if it is present in bitmap passed via DATA. */
159 test_nonssa_use (gimple
, tree t
, tree
, void *data
)
161 t
= get_base_address (t
);
163 if (!t
|| is_gimple_reg (t
))
166 if (TREE_CODE (t
) == PARM_DECL
167 || (TREE_CODE (t
) == VAR_DECL
168 && auto_var_in_fn_p (t
, current_function_decl
))
169 || TREE_CODE (t
) == RESULT_DECL
170 /* Normal labels are part of CFG and will be handled gratefuly.
171 Forced labels however can be used directly by statements and
172 need to stay in one partition along with their uses. */
173 || (TREE_CODE (t
) == LABEL_DECL
174 && FORCED_LABEL (t
)))
175 return bitmap_bit_p ((bitmap
)data
, DECL_UID (t
));
177 /* For DECL_BY_REFERENCE, the return value is actually a pointer. We want
178 to pretend that the value pointed to is actual result decl. */
179 if ((TREE_CODE (t
) == MEM_REF
|| INDIRECT_REF_P (t
))
180 && TREE_CODE (TREE_OPERAND (t
, 0)) == SSA_NAME
181 && SSA_NAME_VAR (TREE_OPERAND (t
, 0))
182 && TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (t
, 0))) == RESULT_DECL
183 && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
185 bitmap_bit_p ((bitmap
)data
,
186 DECL_UID (DECL_RESULT (current_function_decl
)));
191 /* Dump split point CURRENT. */
194 dump_split_point (FILE * file
, struct split_point
*current
)
197 "Split point at BB %i\n"
198 " header time: %i header size: %i\n"
199 " split time: %i split size: %i\n bbs: ",
200 current
->entry_bb
->index
, current
->header_time
,
201 current
->header_size
, current
->split_time
, current
->split_size
);
202 dump_bitmap (file
, current
->split_bbs
);
203 fprintf (file
, " SSA names to pass: ");
204 dump_bitmap (file
, current
->ssa_names_to_pass
);
207 /* Look for all BBs in header that might lead to the split part and verify
208 that they are not defining any non-SSA var used by the split part.
209 Parameters are the same as for consider_split. */
212 verify_non_ssa_vars (struct split_point
*current
, bitmap non_ssa_vars
,
213 basic_block return_bb
)
215 bitmap seen
= BITMAP_ALLOC (NULL
);
216 vec
<basic_block
> worklist
= vNULL
;
222 FOR_EACH_EDGE (e
, ei
, current
->entry_bb
->preds
)
223 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
224 && !bitmap_bit_p (current
->split_bbs
, e
->src
->index
))
226 worklist
.safe_push (e
->src
);
227 bitmap_set_bit (seen
, e
->src
->index
);
230 while (!worklist
.is_empty ())
232 gimple_stmt_iterator bsi
;
234 bb
= worklist
.pop ();
235 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
236 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
237 && bitmap_set_bit (seen
, e
->src
->index
))
239 gcc_checking_assert (!bitmap_bit_p (current
->split_bbs
,
241 worklist
.safe_push (e
->src
);
243 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
245 gimple stmt
= gsi_stmt (bsi
);
246 if (is_gimple_debug (stmt
))
248 if (walk_stmt_load_store_addr_ops
249 (stmt
, non_ssa_vars
, test_nonssa_use
, test_nonssa_use
,
255 if (gimple_code (stmt
) == GIMPLE_LABEL
256 && test_nonssa_use (stmt
, gimple_label_label (stmt
),
257 NULL_TREE
, non_ssa_vars
))
263 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
265 if (walk_stmt_load_store_addr_ops
266 (gsi_stmt (bsi
), non_ssa_vars
, test_nonssa_use
, test_nonssa_use
,
273 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
275 if (e
->dest
!= return_bb
)
277 for (bsi
= gsi_start_phis (return_bb
); !gsi_end_p (bsi
);
280 gimple stmt
= gsi_stmt (bsi
);
281 tree op
= gimple_phi_arg_def (stmt
, e
->dest_idx
);
283 if (virtual_operand_p (gimple_phi_result (stmt
)))
285 if (TREE_CODE (op
) != SSA_NAME
286 && test_nonssa_use (stmt
, op
, op
, non_ssa_vars
))
295 /* Verify that the rest of function does not define any label
296 used by the split part. */
297 FOR_EACH_BB_FN (bb
, cfun
)
298 if (!bitmap_bit_p (current
->split_bbs
, bb
->index
)
299 && !bitmap_bit_p (seen
, bb
->index
))
301 gimple_stmt_iterator bsi
;
302 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
303 if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_LABEL
304 && test_nonssa_use (gsi_stmt (bsi
),
305 gimple_label_label (gsi_stmt (bsi
)),
306 NULL_TREE
, non_ssa_vars
))
311 else if (gimple_code (gsi_stmt (bsi
)) != GIMPLE_LABEL
)
321 /* If STMT is a call, check the callee against a list of forbidden
322 predicate functions. If a match is found, look for uses of the
323 call result in condition statements that compare against zero.
324 For each such use, find the block targeted by the condition
325 statement for the nonzero result, and set the bit for this block
326 in the forbidden dominators bitmap. The purpose of this is to avoid
327 selecting a split point where we are likely to lose the chance
328 to optimize away an unused function call. */
331 check_forbidden_calls (gimple stmt
)
333 imm_use_iterator use_iter
;
337 /* At the moment, __builtin_constant_p is the only forbidden
338 predicate function call (see PR49642). */
339 if (!gimple_call_builtin_p (stmt
, BUILT_IN_CONSTANT_P
))
342 lhs
= gimple_call_lhs (stmt
);
344 if (!lhs
|| TREE_CODE (lhs
) != SSA_NAME
)
347 FOR_EACH_IMM_USE_FAST (use_p
, use_iter
, lhs
)
350 basic_block use_bb
, forbidden_bb
;
352 edge true_edge
, false_edge
;
353 gimple use_stmt
= USE_STMT (use_p
);
355 if (gimple_code (use_stmt
) != GIMPLE_COND
)
358 /* Assuming canonical form for GIMPLE_COND here, with constant
359 in second position. */
360 op1
= gimple_cond_rhs (use_stmt
);
361 code
= gimple_cond_code (use_stmt
);
362 use_bb
= gimple_bb (use_stmt
);
364 extract_true_false_edges_from_block (use_bb
, &true_edge
, &false_edge
);
366 /* We're only interested in comparisons that distinguish
367 unambiguously from zero. */
368 if (!integer_zerop (op1
) || code
== LE_EXPR
|| code
== GE_EXPR
)
372 forbidden_bb
= false_edge
->dest
;
374 forbidden_bb
= true_edge
->dest
;
376 bitmap_set_bit (forbidden_dominators
, forbidden_bb
->index
);
380 /* If BB is dominated by any block in the forbidden dominators set,
381 return TRUE; else FALSE. */
384 dominated_by_forbidden (basic_block bb
)
389 EXECUTE_IF_SET_IN_BITMAP (forbidden_dominators
, 1, dom_bb
, bi
)
391 if (dominated_by_p (CDI_DOMINATORS
, bb
,
392 BASIC_BLOCK_FOR_FN (cfun
, dom_bb
)))
399 /* We found an split_point CURRENT. NON_SSA_VARS is bitmap of all non ssa
400 variables used and RETURN_BB is return basic block.
401 See if we can split function here. */
404 consider_split (struct split_point
*current
, bitmap non_ssa_vars
,
405 basic_block return_bb
)
408 unsigned int num_args
= 0;
409 unsigned int call_overhead
;
412 gimple_stmt_iterator bsi
;
414 int incoming_freq
= 0;
416 bool back_edge
= false;
418 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
419 dump_split_point (dump_file
, current
);
421 FOR_EACH_EDGE (e
, ei
, current
->entry_bb
->preds
)
423 if (e
->flags
& EDGE_DFS_BACK
)
425 if (!bitmap_bit_p (current
->split_bbs
, e
->src
->index
))
426 incoming_freq
+= EDGE_FREQUENCY (e
);
429 /* Do not split when we would end up calling function anyway. */
431 >= (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->frequency
432 * PARAM_VALUE (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY
) / 100))
434 /* When profile is guessed, we can not expect it to give us
435 realistic estimate on likelyness of function taking the
436 complex path. As a special case, when tail of the function is
437 a loop, enable splitting since inlining code skipping the loop
438 is likely noticeable win. */
440 && profile_status_for_fn (cfun
) != PROFILE_READ
441 && incoming_freq
< ENTRY_BLOCK_PTR_FOR_FN (cfun
)->frequency
)
443 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
445 " Split before loop, accepting despite low frequencies %i %i.\n",
447 ENTRY_BLOCK_PTR_FOR_FN (cfun
)->frequency
);
451 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
453 " Refused: incoming frequency is too large.\n");
458 if (!current
->header_size
)
460 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
461 fprintf (dump_file
, " Refused: header empty\n");
465 /* Verify that PHI args on entry are either virtual or all their operands
466 incoming from header are the same. */
467 for (bsi
= gsi_start_phis (current
->entry_bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
469 gimple stmt
= gsi_stmt (bsi
);
472 if (virtual_operand_p (gimple_phi_result (stmt
)))
474 for (i
= 0; i
< gimple_phi_num_args (stmt
); i
++)
476 edge e
= gimple_phi_arg_edge (stmt
, i
);
477 if (!bitmap_bit_p (current
->split_bbs
, e
->src
->index
))
479 tree edge_val
= gimple_phi_arg_def (stmt
, i
);
480 if (val
&& edge_val
!= val
)
482 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
484 " Refused: entry BB has PHI with multiple variants\n");
493 /* See what argument we will pass to the split function and compute
495 call_overhead
= eni_size_weights
.call_cost
;
496 for (parm
= DECL_ARGUMENTS (current_function_decl
); parm
;
497 parm
= DECL_CHAIN (parm
))
499 if (!is_gimple_reg (parm
))
501 if (bitmap_bit_p (non_ssa_vars
, DECL_UID (parm
)))
503 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
505 " Refused: need to pass non-ssa param values\n");
511 tree ddef
= ssa_default_def (cfun
, parm
);
513 && bitmap_bit_p (current
->ssa_names_to_pass
,
514 SSA_NAME_VERSION (ddef
)))
516 if (!VOID_TYPE_P (TREE_TYPE (parm
)))
517 call_overhead
+= estimate_move_cost (TREE_TYPE (parm
));
522 if (!VOID_TYPE_P (TREE_TYPE (current_function_decl
)))
523 call_overhead
+= estimate_move_cost (TREE_TYPE (current_function_decl
));
525 if (current
->split_size
<= call_overhead
)
527 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
529 " Refused: split size is smaller than call overhead\n");
532 if (current
->header_size
+ call_overhead
533 >= (unsigned int)(DECL_DECLARED_INLINE_P (current_function_decl
)
534 ? MAX_INLINE_INSNS_SINGLE
535 : MAX_INLINE_INSNS_AUTO
))
537 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
539 " Refused: header size is too large for inline candidate\n");
543 /* FIXME: we currently can pass only SSA function parameters to the split
544 arguments. Once parm_adjustment infrastructure is supported by cloning,
545 we can pass more than that. */
546 if (num_args
!= bitmap_count_bits (current
->ssa_names_to_pass
))
549 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
551 " Refused: need to pass non-param values\n");
555 /* When there are non-ssa vars used in the split region, see if they
556 are used in the header region. If so, reject the split.
557 FIXME: we can use nested function support to access both. */
558 if (!bitmap_empty_p (non_ssa_vars
)
559 && !verify_non_ssa_vars (current
, non_ssa_vars
, return_bb
))
561 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
563 " Refused: split part has non-ssa uses\n");
567 /* If the split point is dominated by a forbidden block, reject
569 if (!bitmap_empty_p (forbidden_dominators
)
570 && dominated_by_forbidden (current
->entry_bb
))
572 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
574 " Refused: split point dominated by forbidden block\n");
578 /* See if retval used by return bb is computed by header or split part.
579 When it is computed by split part, we need to produce return statement
580 in the split part and add code to header to pass it around.
582 This is bit tricky to test:
583 1) When there is no return_bb or no return value, we always pass
585 2) Invariants are always computed by caller.
586 3) For SSA we need to look if defining statement is in header or split part
587 4) For non-SSA we need to look where the var is computed. */
588 retval
= find_retval (return_bb
);
590 current
->split_part_set_retval
= true;
591 else if (is_gimple_min_invariant (retval
))
592 current
->split_part_set_retval
= false;
593 /* Special case is value returned by reference we record as if it was non-ssa
594 set to result_decl. */
595 else if (TREE_CODE (retval
) == SSA_NAME
596 && SSA_NAME_VAR (retval
)
597 && TREE_CODE (SSA_NAME_VAR (retval
)) == RESULT_DECL
598 && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
599 current
->split_part_set_retval
600 = bitmap_bit_p (non_ssa_vars
, DECL_UID (SSA_NAME_VAR (retval
)));
601 else if (TREE_CODE (retval
) == SSA_NAME
)
602 current
->split_part_set_retval
603 = (!SSA_NAME_IS_DEFAULT_DEF (retval
)
604 && (bitmap_bit_p (current
->split_bbs
,
605 gimple_bb (SSA_NAME_DEF_STMT (retval
))->index
)
606 || gimple_bb (SSA_NAME_DEF_STMT (retval
)) == return_bb
));
607 else if (TREE_CODE (retval
) == PARM_DECL
)
608 current
->split_part_set_retval
= false;
609 else if (TREE_CODE (retval
) == VAR_DECL
610 || TREE_CODE (retval
) == RESULT_DECL
)
611 current
->split_part_set_retval
612 = bitmap_bit_p (non_ssa_vars
, DECL_UID (retval
));
614 current
->split_part_set_retval
= true;
616 /* split_function fixes up at most one PHI non-virtual PHI node in return_bb,
617 for the return value. If there are other PHIs, give up. */
618 if (return_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
620 gimple_stmt_iterator psi
;
622 for (psi
= gsi_start_phis (return_bb
); !gsi_end_p (psi
); gsi_next (&psi
))
623 if (!virtual_operand_p (gimple_phi_result (gsi_stmt (psi
)))
625 && current
->split_part_set_retval
626 && TREE_CODE (retval
) == SSA_NAME
627 && !DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
))
628 && SSA_NAME_DEF_STMT (retval
) == gsi_stmt (psi
)))
630 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
632 " Refused: return bb has extra PHIs\n");
637 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
638 fprintf (dump_file
, " Accepted!\n");
640 /* At the moment chose split point with lowest frequency and that leaves
641 out smallest size of header.
642 In future we might re-consider this heuristics. */
643 if (!best_split_point
.split_bbs
644 || best_split_point
.entry_bb
->frequency
> current
->entry_bb
->frequency
645 || (best_split_point
.entry_bb
->frequency
== current
->entry_bb
->frequency
646 && best_split_point
.split_size
< current
->split_size
))
649 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
650 fprintf (dump_file
, " New best split point!\n");
651 if (best_split_point
.ssa_names_to_pass
)
653 BITMAP_FREE (best_split_point
.ssa_names_to_pass
);
654 BITMAP_FREE (best_split_point
.split_bbs
);
656 best_split_point
= *current
;
657 best_split_point
.ssa_names_to_pass
= BITMAP_ALLOC (NULL
);
658 bitmap_copy (best_split_point
.ssa_names_to_pass
,
659 current
->ssa_names_to_pass
);
660 best_split_point
.split_bbs
= BITMAP_ALLOC (NULL
);
661 bitmap_copy (best_split_point
.split_bbs
, current
->split_bbs
);
665 /* Return basic block containing RETURN statement. We allow basic blocks
669 but return_bb can not be more complex than this.
670 If nothing is found, return the exit block.
672 When there are multiple RETURN statement, chose one with return value,
673 since that one is more likely shared by multiple code paths.
675 Return BB is special, because for function splitting it is the only
676 basic block that is duplicated in between header and split part of the
679 TODO: We might support multiple return blocks. */
682 find_return_bb (void)
685 basic_block return_bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
);
686 gimple_stmt_iterator bsi
;
687 bool found_return
= false;
688 tree retval
= NULL_TREE
;
690 if (!single_pred_p (EXIT_BLOCK_PTR_FOR_FN (cfun
)))
693 e
= single_pred_edge (EXIT_BLOCK_PTR_FOR_FN (cfun
));
694 for (bsi
= gsi_last_bb (e
->src
); !gsi_end_p (bsi
); gsi_prev (&bsi
))
696 gimple stmt
= gsi_stmt (bsi
);
697 if (gimple_code (stmt
) == GIMPLE_LABEL
698 || is_gimple_debug (stmt
)
699 || gimple_clobber_p (stmt
))
701 else if (gimple_code (stmt
) == GIMPLE_ASSIGN
703 && gimple_assign_single_p (stmt
)
704 && (auto_var_in_fn_p (gimple_assign_rhs1 (stmt
),
705 current_function_decl
)
706 || is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
707 && retval
== gimple_assign_lhs (stmt
))
709 else if (gimple_code (stmt
) == GIMPLE_RETURN
)
712 retval
= gimple_return_retval (stmt
);
717 if (gsi_end_p (bsi
) && found_return
)
723 /* Given return basic block RETURN_BB, see where return value is really
726 find_retval (basic_block return_bb
)
728 gimple_stmt_iterator bsi
;
729 for (bsi
= gsi_start_bb (return_bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
730 if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_RETURN
)
731 return gimple_return_retval (gsi_stmt (bsi
));
732 else if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_ASSIGN
733 && !gimple_clobber_p (gsi_stmt (bsi
)))
734 return gimple_assign_rhs1 (gsi_stmt (bsi
));
738 /* Callback for walk_stmt_load_store_addr_ops. If T is non-SSA automatic
739 variable, mark it as used in bitmap passed via DATA.
740 Return true when access to T prevents splitting the function. */
743 mark_nonssa_use (gimple
, tree t
, tree
, void *data
)
745 t
= get_base_address (t
);
747 if (!t
|| is_gimple_reg (t
))
750 /* At present we can't pass non-SSA arguments to split function.
751 FIXME: this can be relaxed by passing references to arguments. */
752 if (TREE_CODE (t
) == PARM_DECL
)
754 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
756 "Cannot split: use of non-ssa function parameter.\n");
760 if ((TREE_CODE (t
) == VAR_DECL
761 && auto_var_in_fn_p (t
, current_function_decl
))
762 || TREE_CODE (t
) == RESULT_DECL
763 || (TREE_CODE (t
) == LABEL_DECL
764 && FORCED_LABEL (t
)))
765 bitmap_set_bit ((bitmap
)data
, DECL_UID (t
));
767 /* For DECL_BY_REFERENCE, the return value is actually a pointer. We want
768 to pretend that the value pointed to is actual result decl. */
769 if ((TREE_CODE (t
) == MEM_REF
|| INDIRECT_REF_P (t
))
770 && TREE_CODE (TREE_OPERAND (t
, 0)) == SSA_NAME
771 && SSA_NAME_VAR (TREE_OPERAND (t
, 0))
772 && TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (t
, 0))) == RESULT_DECL
773 && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
775 bitmap_bit_p ((bitmap
)data
,
776 DECL_UID (DECL_RESULT (current_function_decl
)));
781 /* Compute local properties of basic block BB we collect when looking for
782 split points. We look for ssa defs and store them in SET_SSA_NAMES,
783 for ssa uses and store them in USED_SSA_NAMES and for any non-SSA automatic
784 vars stored in NON_SSA_VARS.
786 When BB has edge to RETURN_BB, collect uses in RETURN_BB too.
788 Return false when BB contains something that prevents it from being put into
792 visit_bb (basic_block bb
, basic_block return_bb
,
793 bitmap set_ssa_names
, bitmap used_ssa_names
,
796 gimple_stmt_iterator bsi
;
799 bool can_split
= true;
801 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
803 gimple stmt
= gsi_stmt (bsi
);
808 if (is_gimple_debug (stmt
))
811 if (gimple_clobber_p (stmt
))
814 /* FIXME: We can split regions containing EH. We can not however
815 split RESX, EH_DISPATCH and EH_POINTER referring to same region
816 into different partitions. This would require tracking of
817 EH regions and checking in consider_split_point if they
818 are not used elsewhere. */
819 if (gimple_code (stmt
) == GIMPLE_RESX
)
821 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
822 fprintf (dump_file
, "Cannot split: resx.\n");
825 if (gimple_code (stmt
) == GIMPLE_EH_DISPATCH
)
827 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
828 fprintf (dump_file
, "Cannot split: eh dispatch.\n");
832 /* Check builtins that prevent splitting. */
833 if (gimple_code (stmt
) == GIMPLE_CALL
834 && (decl
= gimple_call_fndecl (stmt
)) != NULL_TREE
835 && DECL_BUILT_IN (decl
)
836 && DECL_BUILT_IN_CLASS (decl
) == BUILT_IN_NORMAL
)
837 switch (DECL_FUNCTION_CODE (decl
))
839 /* FIXME: once we will allow passing non-parm values to split part,
840 we need to be sure to handle correct builtin_stack_save and
841 builtin_stack_restore. At the moment we are safe; there is no
842 way to store builtin_stack_save result in non-SSA variable
843 since all calls to those are compiler generated. */
845 case BUILT_IN_APPLY_ARGS
:
846 case BUILT_IN_VA_START
:
847 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
849 "Cannot split: builtin_apply and va_start.\n");
852 case BUILT_IN_EH_POINTER
:
853 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
854 fprintf (dump_file
, "Cannot split: builtin_eh_pointer.\n");
861 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_DEF
)
862 bitmap_set_bit (set_ssa_names
, SSA_NAME_VERSION (op
));
863 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
864 bitmap_set_bit (used_ssa_names
, SSA_NAME_VERSION (op
));
865 can_split
&= !walk_stmt_load_store_addr_ops (stmt
, non_ssa_vars
,
870 for (bsi
= gsi_start_phis (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
872 gimple stmt
= gsi_stmt (bsi
);
875 if (virtual_operand_p (gimple_phi_result (stmt
)))
877 bitmap_set_bit (set_ssa_names
,
878 SSA_NAME_VERSION (gimple_phi_result (stmt
)));
879 for (i
= 0; i
< gimple_phi_num_args (stmt
); i
++)
881 tree op
= gimple_phi_arg_def (stmt
, i
);
882 if (TREE_CODE (op
) == SSA_NAME
)
883 bitmap_set_bit (used_ssa_names
, SSA_NAME_VERSION (op
));
885 can_split
&= !walk_stmt_load_store_addr_ops (stmt
, non_ssa_vars
,
890 /* Record also uses coming from PHI operand in return BB. */
891 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
892 if (e
->dest
== return_bb
)
894 for (bsi
= gsi_start_phis (return_bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
896 gimple stmt
= gsi_stmt (bsi
);
897 tree op
= gimple_phi_arg_def (stmt
, e
->dest_idx
);
899 if (virtual_operand_p (gimple_phi_result (stmt
)))
901 if (TREE_CODE (op
) == SSA_NAME
)
902 bitmap_set_bit (used_ssa_names
, SSA_NAME_VERSION (op
));
904 can_split
&= !mark_nonssa_use (stmt
, op
, op
, non_ssa_vars
);
910 /* Stack entry for recursive DFS walk in find_split_point. */
914 /* Basic block we are examining. */
917 /* SSA names set and used by the BB and all BBs reachable
918 from it via DFS walk. */
919 bitmap set_ssa_names
, used_ssa_names
;
922 /* All BBS visited from this BB via DFS walk. */
925 /* Last examined edge in DFS walk. Since we walk unoriented graph,
926 the value is up to sum of incoming and outgoing edges of BB. */
927 unsigned int edge_num
;
929 /* Stack entry index of earliest BB reachable from current BB
930 or any BB visited later in DFS walk. */
933 /* Overall time and size of all BBs reached from this BB in DFS walk. */
934 int overall_time
, overall_size
;
936 /* When false we can not split on this BB. */
941 /* Find all articulations and call consider_split on them.
942 OVERALL_TIME and OVERALL_SIZE is time and size of the function.
944 We perform basic algorithm for finding an articulation in a graph
945 created from CFG by considering it to be an unoriented graph.
947 The articulation is discovered via DFS walk. We collect earliest
948 basic block on stack that is reachable via backward edge. Articulation
949 is any basic block such that there is no backward edge bypassing it.
950 To reduce stack usage we maintain heap allocated stack in STACK vector.
951 AUX pointer of BB is set to index it appears in the stack or -1 once
952 it is visited and popped off the stack.
954 The algorithm finds articulation after visiting the whole component
955 reachable by it. This makes it convenient to collect information about
956 the component used by consider_split. */
959 find_split_points (int overall_time
, int overall_size
)
962 vec
<stack_entry
> stack
= vNULL
;
964 basic_block return_bb
= find_return_bb ();
965 struct split_point current
;
967 current
.header_time
= overall_time
;
968 current
.header_size
= overall_size
;
969 current
.split_time
= 0;
970 current
.split_size
= 0;
971 current
.ssa_names_to_pass
= BITMAP_ALLOC (NULL
);
973 first
.bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
975 first
.overall_time
= 0;
976 first
.overall_size
= 0;
977 first
.earliest
= INT_MAX
;
978 first
.set_ssa_names
= 0;
979 first
.used_ssa_names
= 0;
980 first
.non_ssa_vars
= 0;
981 first
.bbs_visited
= 0;
982 first
.can_split
= false;
983 stack
.safe_push (first
);
984 ENTRY_BLOCK_PTR_FOR_FN (cfun
)->aux
= (void *)(intptr_t)-1;
986 while (!stack
.is_empty ())
988 stack_entry
*entry
= &stack
.last ();
990 /* We are walking an acyclic graph, so edge_num counts
991 succ and pred edges together. However when considering
992 articulation, we want to have processed everything reachable
993 from articulation but nothing that reaches into it. */
994 if (entry
->edge_num
== EDGE_COUNT (entry
->bb
->succs
)
995 && entry
->bb
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
))
997 int pos
= stack
.length ();
998 entry
->can_split
&= visit_bb (entry
->bb
, return_bb
,
999 entry
->set_ssa_names
,
1000 entry
->used_ssa_names
,
1001 entry
->non_ssa_vars
);
1002 if (pos
<= entry
->earliest
&& !entry
->can_split
1003 && dump_file
&& (dump_flags
& TDF_DETAILS
))
1005 "found articulation at bb %i but can not split\n",
1007 if (pos
<= entry
->earliest
&& entry
->can_split
)
1009 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1010 fprintf (dump_file
, "found articulation at bb %i\n",
1012 current
.entry_bb
= entry
->bb
;
1013 current
.ssa_names_to_pass
= BITMAP_ALLOC (NULL
);
1014 bitmap_and_compl (current
.ssa_names_to_pass
,
1015 entry
->used_ssa_names
, entry
->set_ssa_names
);
1016 current
.header_time
= overall_time
- entry
->overall_time
;
1017 current
.header_size
= overall_size
- entry
->overall_size
;
1018 current
.split_time
= entry
->overall_time
;
1019 current
.split_size
= entry
->overall_size
;
1020 current
.split_bbs
= entry
->bbs_visited
;
1021 consider_split (¤t
, entry
->non_ssa_vars
, return_bb
);
1022 BITMAP_FREE (current
.ssa_names_to_pass
);
1025 /* Do actual DFS walk. */
1027 < (EDGE_COUNT (entry
->bb
->succs
)
1028 + EDGE_COUNT (entry
->bb
->preds
)))
1032 if (entry
->edge_num
< EDGE_COUNT (entry
->bb
->succs
))
1034 e
= EDGE_SUCC (entry
->bb
, entry
->edge_num
);
1039 e
= EDGE_PRED (entry
->bb
, entry
->edge_num
1040 - EDGE_COUNT (entry
->bb
->succs
));
1046 /* New BB to visit, push it to the stack. */
1047 if (dest
!= return_bb
&& dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1050 stack_entry new_entry
;
1052 new_entry
.bb
= dest
;
1053 new_entry
.edge_num
= 0;
1054 new_entry
.overall_time
1055 = bb_info_vec
[dest
->index
].time
;
1056 new_entry
.overall_size
1057 = bb_info_vec
[dest
->index
].size
;
1058 new_entry
.earliest
= INT_MAX
;
1059 new_entry
.set_ssa_names
= BITMAP_ALLOC (NULL
);
1060 new_entry
.used_ssa_names
= BITMAP_ALLOC (NULL
);
1061 new_entry
.bbs_visited
= BITMAP_ALLOC (NULL
);
1062 new_entry
.non_ssa_vars
= BITMAP_ALLOC (NULL
);
1063 new_entry
.can_split
= true;
1064 bitmap_set_bit (new_entry
.bbs_visited
, dest
->index
);
1065 stack
.safe_push (new_entry
);
1066 dest
->aux
= (void *)(intptr_t)stack
.length ();
1068 /* Back edge found, record the earliest point. */
1069 else if ((intptr_t)dest
->aux
> 0
1070 && (intptr_t)dest
->aux
< entry
->earliest
)
1071 entry
->earliest
= (intptr_t)dest
->aux
;
1073 /* We are done with examining the edges. Pop off the value from stack
1074 and merge stuff we accumulate during the walk. */
1075 else if (entry
->bb
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1077 stack_entry
*prev
= &stack
[stack
.length () - 2];
1079 entry
->bb
->aux
= (void *)(intptr_t)-1;
1080 prev
->can_split
&= entry
->can_split
;
1081 if (prev
->set_ssa_names
)
1083 bitmap_ior_into (prev
->set_ssa_names
, entry
->set_ssa_names
);
1084 bitmap_ior_into (prev
->used_ssa_names
, entry
->used_ssa_names
);
1085 bitmap_ior_into (prev
->bbs_visited
, entry
->bbs_visited
);
1086 bitmap_ior_into (prev
->non_ssa_vars
, entry
->non_ssa_vars
);
1088 if (prev
->earliest
> entry
->earliest
)
1089 prev
->earliest
= entry
->earliest
;
1090 prev
->overall_time
+= entry
->overall_time
;
1091 prev
->overall_size
+= entry
->overall_size
;
1092 BITMAP_FREE (entry
->set_ssa_names
);
1093 BITMAP_FREE (entry
->used_ssa_names
);
1094 BITMAP_FREE (entry
->bbs_visited
);
1095 BITMAP_FREE (entry
->non_ssa_vars
);
1101 ENTRY_BLOCK_PTR_FOR_FN (cfun
)->aux
= NULL
;
1102 FOR_EACH_BB_FN (bb
, cfun
)
1105 BITMAP_FREE (current
.ssa_names_to_pass
);
1108 /* Split function at SPLIT_POINT. */
1111 split_function (struct split_point
*split_point
)
1113 vec
<tree
> args_to_pass
= vNULL
;
1114 bitmap args_to_skip
;
1117 struct cgraph_node
*node
, *cur_node
= cgraph_get_node (current_function_decl
);
1118 basic_block return_bb
= find_return_bb ();
1119 basic_block call_bb
;
1120 gimple_stmt_iterator gsi
;
1124 tree retval
= NULL
, real_retval
= NULL
;
1125 bool split_part_return_p
= false;
1126 gimple last_stmt
= NULL
;
1129 vec
<tree
, va_gc
> **debug_args
= NULL
;
1133 fprintf (dump_file
, "\n\nSplitting function at:\n");
1134 dump_split_point (dump_file
, split_point
);
1137 if (cur_node
->local
.can_change_signature
)
1138 args_to_skip
= BITMAP_ALLOC (NULL
);
1140 args_to_skip
= NULL
;
1142 /* Collect the parameters of new function and args_to_skip bitmap. */
1143 for (parm
= DECL_ARGUMENTS (current_function_decl
);
1144 parm
; parm
= DECL_CHAIN (parm
), num
++)
1146 && (!is_gimple_reg (parm
)
1147 || (ddef
= ssa_default_def (cfun
, parm
)) == NULL_TREE
1148 || !bitmap_bit_p (split_point
->ssa_names_to_pass
,
1149 SSA_NAME_VERSION (ddef
))))
1150 bitmap_set_bit (args_to_skip
, num
);
1153 /* This parm might not have been used up to now, but is going to be
1154 used, hence register it. */
1155 if (is_gimple_reg (parm
))
1156 arg
= get_or_create_ssa_default_def (cfun
, parm
);
1160 if (!useless_type_conversion_p (DECL_ARG_TYPE (parm
), TREE_TYPE (arg
)))
1161 arg
= fold_convert (DECL_ARG_TYPE (parm
), arg
);
1162 args_to_pass
.safe_push (arg
);
1165 /* See if the split function will return. */
1166 FOR_EACH_EDGE (e
, ei
, return_bb
->preds
)
1167 if (bitmap_bit_p (split_point
->split_bbs
, e
->src
->index
))
1170 split_part_return_p
= true;
1172 /* Add return block to what will become the split function.
1173 We do not return; no return block is needed. */
1174 if (!split_part_return_p
)
1176 /* We have no return block, so nothing is needed. */
1177 else if (return_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1179 /* When we do not want to return value, we need to construct
1180 new return block with empty return statement.
1181 FIXME: Once we are able to change return type, we should change function
1182 to return void instead of just outputting function with undefined return
1183 value. For structures this affects quality of codegen. */
1184 else if (!split_point
->split_part_set_retval
1185 && find_retval (return_bb
))
1187 bool redirected
= true;
1188 basic_block new_return_bb
= create_basic_block (NULL
, 0, return_bb
);
1189 gimple_stmt_iterator gsi
= gsi_start_bb (new_return_bb
);
1190 gsi_insert_after (&gsi
, gimple_build_return (NULL
), GSI_NEW_STMT
);
1194 FOR_EACH_EDGE (e
, ei
, return_bb
->preds
)
1195 if (bitmap_bit_p (split_point
->split_bbs
, e
->src
->index
))
1197 new_return_bb
->count
+= e
->count
;
1198 new_return_bb
->frequency
+= EDGE_FREQUENCY (e
);
1199 redirect_edge_and_branch (e
, new_return_bb
);
1204 e
= make_edge (new_return_bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), 0);
1205 e
->probability
= REG_BR_PROB_BASE
;
1206 e
->count
= new_return_bb
->count
;
1208 add_bb_to_loop (new_return_bb
, current_loops
->tree_root
);
1209 bitmap_set_bit (split_point
->split_bbs
, new_return_bb
->index
);
1211 /* When we pass around the value, use existing return block. */
1213 bitmap_set_bit (split_point
->split_bbs
, return_bb
->index
);
1215 /* If RETURN_BB has virtual operand PHIs, they must be removed and the
1216 virtual operand marked for renaming as we change the CFG in a way that
1217 tree-inline is not able to compensate for.
1219 Note this can happen whether or not we have a return value. If we have
1220 a return value, then RETURN_BB may have PHIs for real operands too. */
1221 if (return_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1224 for (gsi
= gsi_start_phis (return_bb
); !gsi_end_p (gsi
);)
1226 gimple stmt
= gsi_stmt (gsi
);
1227 if (!virtual_operand_p (gimple_phi_result (stmt
)))
1232 mark_virtual_phi_result_for_renaming (stmt
);
1233 remove_phi_node (&gsi
, true);
1236 /* In reality we have to rename the reaching definition of the
1237 virtual operand at return_bb as we will eventually release it
1238 when we remove the code region we outlined.
1239 So we have to rename all immediate virtual uses of that region
1240 if we didn't see a PHI definition yet. */
1241 /* ??? In real reality we want to set the reaching vdef of the
1242 entry of the SESE region as the vuse of the call and the reaching
1243 vdef of the exit of the SESE region as the vdef of the call. */
1245 for (gsi
= gsi_start_bb (return_bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1247 gimple stmt
= gsi_stmt (gsi
);
1248 if (gimple_vuse (stmt
))
1250 gimple_set_vuse (stmt
, NULL_TREE
);
1253 if (gimple_vdef (stmt
))
1258 /* Now create the actual clone. */
1259 rebuild_cgraph_edges ();
1260 node
= cgraph_function_versioning (cur_node
, vNULL
,
1263 !split_part_return_p
,
1264 split_point
->split_bbs
,
1265 split_point
->entry_bb
, "part");
1267 /* Let's take a time profile for splitted function. */
1268 node
->tp_first_run
= cur_node
->tp_first_run
+ 1;
1270 /* For usual cloning it is enough to clear builtin only when signature
1271 changes. For partial inlining we however can not expect the part
1272 of builtin implementation to have same semantic as the whole. */
1273 if (DECL_BUILT_IN (node
->decl
))
1275 DECL_BUILT_IN_CLASS (node
->decl
) = NOT_BUILT_IN
;
1276 DECL_FUNCTION_CODE (node
->decl
) = (enum built_in_function
) 0;
1278 /* If the original function is declared inline, there is no point in issuing
1279 a warning for the non-inlinable part. */
1280 DECL_NO_INLINE_WARNING_P (node
->decl
) = 1;
1281 cgraph_node_remove_callees (cur_node
);
1282 ipa_remove_all_references (&cur_node
->ref_list
);
1283 if (!split_part_return_p
)
1284 TREE_THIS_VOLATILE (node
->decl
) = 1;
1286 dump_function_to_file (node
->decl
, dump_file
, dump_flags
);
1288 /* Create the basic block we place call into. It is the entry basic block
1289 split after last label. */
1290 call_bb
= split_point
->entry_bb
;
1291 for (gsi
= gsi_start_bb (call_bb
); !gsi_end_p (gsi
);)
1292 if (gimple_code (gsi_stmt (gsi
)) == GIMPLE_LABEL
)
1294 last_stmt
= gsi_stmt (gsi
);
1299 e
= split_block (split_point
->entry_bb
, last_stmt
);
1302 /* Produce the call statement. */
1303 gsi
= gsi_last_bb (call_bb
);
1304 FOR_EACH_VEC_ELT (args_to_pass
, i
, arg
)
1305 if (!is_gimple_val (arg
))
1307 arg
= force_gimple_operand_gsi (&gsi
, arg
, true, NULL_TREE
,
1308 false, GSI_CONTINUE_LINKING
);
1309 args_to_pass
[i
] = arg
;
1311 call
= gimple_build_call_vec (node
->decl
, args_to_pass
);
1312 gimple_set_block (call
, DECL_INITIAL (current_function_decl
));
1313 args_to_pass
.release ();
1315 /* For optimized away parameters, add on the caller side
1317 DEBUG D#X => parm_Y(D)
1318 stmts and associate D#X with parm in decl_debug_args_lookup
1319 vector to say for debug info that if parameter parm had been passed,
1320 it would have value parm_Y(D). */
1322 for (parm
= DECL_ARGUMENTS (current_function_decl
), num
= 0;
1323 parm
; parm
= DECL_CHAIN (parm
), num
++)
1324 if (bitmap_bit_p (args_to_skip
, num
)
1325 && is_gimple_reg (parm
))
1330 /* This needs to be done even without MAY_HAVE_DEBUG_STMTS,
1331 otherwise if it didn't exist before, we'd end up with
1332 different SSA_NAME_VERSIONs between -g and -g0. */
1333 arg
= get_or_create_ssa_default_def (cfun
, parm
);
1334 if (!MAY_HAVE_DEBUG_STMTS
)
1337 if (debug_args
== NULL
)
1338 debug_args
= decl_debug_args_insert (node
->decl
);
1339 ddecl
= make_node (DEBUG_EXPR_DECL
);
1340 DECL_ARTIFICIAL (ddecl
) = 1;
1341 TREE_TYPE (ddecl
) = TREE_TYPE (parm
);
1342 DECL_MODE (ddecl
) = DECL_MODE (parm
);
1343 vec_safe_push (*debug_args
, DECL_ORIGIN (parm
));
1344 vec_safe_push (*debug_args
, ddecl
);
1345 def_temp
= gimple_build_debug_bind (ddecl
, unshare_expr (arg
),
1347 gsi_insert_after (&gsi
, def_temp
, GSI_NEW_STMT
);
1349 /* And on the callee side, add
1352 stmts to the first bb where var is a VAR_DECL created for the
1353 optimized away parameter in DECL_INITIAL block. This hints
1354 in the debug info that var (whole DECL_ORIGIN is the parm PARM_DECL)
1355 is optimized away, but could be looked up at the call site
1356 as value of D#X there. */
1357 if (debug_args
!= NULL
)
1361 gimple_stmt_iterator cgsi
;
1364 push_cfun (DECL_STRUCT_FUNCTION (node
->decl
));
1365 var
= BLOCK_VARS (DECL_INITIAL (node
->decl
));
1366 i
= vec_safe_length (*debug_args
);
1367 cgsi
= gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun
)));
1371 while (var
!= NULL_TREE
1372 && DECL_ABSTRACT_ORIGIN (var
) != (**debug_args
)[i
])
1373 var
= TREE_CHAIN (var
);
1374 if (var
== NULL_TREE
)
1376 vexpr
= make_node (DEBUG_EXPR_DECL
);
1377 parm
= (**debug_args
)[i
];
1378 DECL_ARTIFICIAL (vexpr
) = 1;
1379 TREE_TYPE (vexpr
) = TREE_TYPE (parm
);
1380 DECL_MODE (vexpr
) = DECL_MODE (parm
);
1381 def_temp
= gimple_build_debug_source_bind (vexpr
, parm
,
1383 gsi_insert_before (&cgsi
, def_temp
, GSI_SAME_STMT
);
1384 def_temp
= gimple_build_debug_bind (var
, vexpr
, NULL
);
1385 gsi_insert_before (&cgsi
, def_temp
, GSI_SAME_STMT
);
1391 /* We avoid address being taken on any variable used by split part,
1392 so return slot optimization is always possible. Moreover this is
1393 required to make DECL_BY_REFERENCE work. */
1394 if (aggregate_value_p (DECL_RESULT (current_function_decl
),
1395 TREE_TYPE (current_function_decl
))
1396 && (!is_gimple_reg_type (TREE_TYPE (DECL_RESULT (current_function_decl
)))
1397 || DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
))))
1398 gimple_call_set_return_slot_opt (call
, true);
1400 /* Update return value. This is bit tricky. When we do not return,
1401 do nothing. When we return we might need to update return_bb
1402 or produce a new return statement. */
1403 if (!split_part_return_p
)
1404 gsi_insert_after (&gsi
, call
, GSI_NEW_STMT
);
1407 e
= make_edge (call_bb
, return_bb
,
1408 return_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
1409 ? 0 : EDGE_FALLTHRU
);
1410 e
->count
= call_bb
->count
;
1411 e
->probability
= REG_BR_PROB_BASE
;
1413 /* If there is return basic block, see what value we need to store
1414 return value into and put call just before it. */
1415 if (return_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1417 real_retval
= retval
= find_retval (return_bb
);
1419 if (real_retval
&& split_point
->split_part_set_retval
)
1421 gimple_stmt_iterator psi
;
1423 /* See if we need new SSA_NAME for the result.
1424 When DECL_BY_REFERENCE is true, retval is actually pointer to
1425 return value and it is constant in whole function. */
1426 if (TREE_CODE (retval
) == SSA_NAME
1427 && !DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
1429 retval
= copy_ssa_name (retval
, call
);
1431 /* See if there is PHI defining return value. */
1432 for (psi
= gsi_start_phis (return_bb
);
1433 !gsi_end_p (psi
); gsi_next (&psi
))
1434 if (!virtual_operand_p (gimple_phi_result (gsi_stmt (psi
))))
1437 /* When there is PHI, just update its value. */
1438 if (TREE_CODE (retval
) == SSA_NAME
1439 && !gsi_end_p (psi
))
1440 add_phi_arg (gsi_stmt (psi
), retval
, e
, UNKNOWN_LOCATION
);
1441 /* Otherwise update the return BB itself.
1442 find_return_bb allows at most one assignment to return value,
1443 so update first statement. */
1446 gimple_stmt_iterator bsi
;
1447 for (bsi
= gsi_start_bb (return_bb
); !gsi_end_p (bsi
);
1449 if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_RETURN
)
1451 gimple_return_set_retval (gsi_stmt (bsi
), retval
);
1454 else if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_ASSIGN
1455 && !gimple_clobber_p (gsi_stmt (bsi
)))
1457 gimple_assign_set_rhs1 (gsi_stmt (bsi
), retval
);
1460 update_stmt (gsi_stmt (bsi
));
1463 if (DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
1465 gimple_call_set_lhs (call
, build_simple_mem_ref (retval
));
1466 gsi_insert_after (&gsi
, call
, GSI_NEW_STMT
);
1471 restype
= TREE_TYPE (DECL_RESULT (current_function_decl
));
1472 gsi_insert_after (&gsi
, call
, GSI_NEW_STMT
);
1473 if (!useless_type_conversion_p (TREE_TYPE (retval
), restype
))
1476 tree tem
= create_tmp_reg (restype
, NULL
);
1477 tem
= make_ssa_name (tem
, call
);
1478 cpy
= gimple_build_assign_with_ops (NOP_EXPR
, retval
,
1480 gsi_insert_after (&gsi
, cpy
, GSI_NEW_STMT
);
1483 gimple_call_set_lhs (call
, retval
);
1488 gsi_insert_after (&gsi
, call
, GSI_NEW_STMT
);
1490 /* We don't use return block (there is either no return in function or
1491 multiple of them). So create new basic block with return statement.
1496 if (split_point
->split_part_set_retval
1497 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (current_function_decl
))))
1499 retval
= DECL_RESULT (current_function_decl
);
1501 /* We use temporary register to hold value when aggregate_value_p
1502 is false. Similarly for DECL_BY_REFERENCE we must avoid extra
1504 if (!aggregate_value_p (retval
, TREE_TYPE (current_function_decl
))
1505 && !DECL_BY_REFERENCE (retval
))
1506 retval
= create_tmp_reg (TREE_TYPE (retval
), NULL
);
1507 if (is_gimple_reg (retval
))
1509 /* When returning by reference, there is only one SSA name
1510 assigned to RESULT_DECL (that is pointer to return value).
1511 Look it up or create new one if it is missing. */
1512 if (DECL_BY_REFERENCE (retval
))
1513 retval
= get_or_create_ssa_default_def (cfun
, retval
);
1514 /* Otherwise produce new SSA name for return value. */
1516 retval
= make_ssa_name (retval
, call
);
1518 if (DECL_BY_REFERENCE (DECL_RESULT (current_function_decl
)))
1519 gimple_call_set_lhs (call
, build_simple_mem_ref (retval
));
1521 gimple_call_set_lhs (call
, retval
);
1523 gsi_insert_after (&gsi
, call
, GSI_NEW_STMT
);
1524 ret
= gimple_build_return (retval
);
1525 gsi_insert_after (&gsi
, ret
, GSI_NEW_STMT
);
1528 free_dominance_info (CDI_DOMINATORS
);
1529 free_dominance_info (CDI_POST_DOMINATORS
);
1530 compute_inline_parameters (node
, true);
1533 /* Execute function splitting pass. */
1536 execute_split_functions (void)
1538 gimple_stmt_iterator bsi
;
1540 int overall_time
= 0, overall_size
= 0;
1542 struct cgraph_node
*node
= cgraph_get_node (current_function_decl
);
1544 if (flags_from_decl_or_type (current_function_decl
)
1545 & (ECF_NORETURN
|ECF_MALLOC
))
1548 fprintf (dump_file
, "Not splitting: noreturn/malloc function.\n");
1551 if (MAIN_NAME_P (DECL_NAME (current_function_decl
)))
1554 fprintf (dump_file
, "Not splitting: main function.\n");
1557 /* This can be relaxed; function might become inlinable after splitting
1558 away the uninlinable part. */
1559 if (inline_edge_summary_vec
.exists ()
1560 && !inline_summary (node
)->inlinable
)
1563 fprintf (dump_file
, "Not splitting: not inlinable.\n");
1566 if (DECL_DISREGARD_INLINE_LIMITS (node
->decl
))
1569 fprintf (dump_file
, "Not splitting: disregarding inline limits.\n");
1572 /* This can be relaxed; most of versioning tests actually prevents
1574 if (!tree_versionable_function_p (current_function_decl
))
1577 fprintf (dump_file
, "Not splitting: not versionable.\n");
1580 /* FIXME: we could support this. */
1581 if (DECL_STRUCT_FUNCTION (current_function_decl
)->static_chain_decl
)
1584 fprintf (dump_file
, "Not splitting: nested function.\n");
1588 /* See if it makes sense to try to split.
1589 It makes sense to split if we inline, that is if we have direct calls to
1590 handle or direct calls are possibly going to appear as result of indirect
1591 inlining or LTO. Also handle -fprofile-generate as LTO to allow non-LTO
1592 training for LTO -fprofile-use build.
1594 Note that we are not completely conservative about disqualifying functions
1595 called once. It is possible that the caller is called more then once and
1596 then inlining would still benefit. */
1598 /* Local functions called once will be completely inlined most of time. */
1599 || (!node
->callers
->next_caller
&& node
->local
.local
))
1600 && !node
->address_taken
1601 && (!flag_lto
|| !node
->externally_visible
))
1604 fprintf (dump_file
, "Not splitting: not called directly "
1605 "or called once.\n");
1609 /* FIXME: We can actually split if splitting reduces call overhead. */
1610 if (!flag_inline_small_functions
1611 && !DECL_DECLARED_INLINE_P (current_function_decl
))
1614 fprintf (dump_file
, "Not splitting: not autoinlining and function"
1615 " is not inline.\n");
1619 /* We enforce splitting after loop headers when profile info is not
1621 if (profile_status_for_fn (cfun
) != PROFILE_READ
)
1622 mark_dfs_back_edges ();
1624 /* Initialize bitmap to track forbidden calls. */
1625 forbidden_dominators
= BITMAP_ALLOC (NULL
);
1626 calculate_dominance_info (CDI_DOMINATORS
);
1628 /* Compute local info about basic blocks and determine function size/time. */
1629 bb_info_vec
.safe_grow_cleared (last_basic_block_for_fn (cfun
) + 1);
1630 memset (&best_split_point
, 0, sizeof (best_split_point
));
1631 FOR_EACH_BB_FN (bb
, cfun
)
1635 int freq
= compute_call_stmt_bb_frequency (current_function_decl
, bb
);
1637 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1638 fprintf (dump_file
, "Basic block %i\n", bb
->index
);
1640 for (bsi
= gsi_start_bb (bb
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1642 int this_time
, this_size
;
1643 gimple stmt
= gsi_stmt (bsi
);
1645 this_size
= estimate_num_insns (stmt
, &eni_size_weights
);
1646 this_time
= estimate_num_insns (stmt
, &eni_time_weights
) * freq
;
1649 check_forbidden_calls (stmt
);
1651 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1653 fprintf (dump_file
, " freq:%6i size:%3i time:%3i ",
1654 freq
, this_size
, this_time
);
1655 print_gimple_stmt (dump_file
, stmt
, 0, 0);
1658 overall_time
+= time
;
1659 overall_size
+= size
;
1660 bb_info_vec
[bb
->index
].time
= time
;
1661 bb_info_vec
[bb
->index
].size
= size
;
1663 find_split_points (overall_time
, overall_size
);
1664 if (best_split_point
.split_bbs
)
1666 split_function (&best_split_point
);
1667 BITMAP_FREE (best_split_point
.ssa_names_to_pass
);
1668 BITMAP_FREE (best_split_point
.split_bbs
);
1669 todo
= TODO_update_ssa
| TODO_cleanup_cfg
;
1671 BITMAP_FREE (forbidden_dominators
);
1672 bb_info_vec
.release ();
1676 /* Gate function splitting pass. When doing profile feedback, we want
1677 to execute the pass after profiling is read. So disable one in
1678 early optimization. */
1681 gate_split_functions (void)
1683 return (flag_partial_inlining
1684 && !profile_arc_flag
&& !flag_branch_probabilities
);
1689 const pass_data pass_data_split_functions
=
1691 GIMPLE_PASS
, /* type */
1692 "fnsplit", /* name */
1693 OPTGROUP_NONE
, /* optinfo_flags */
1694 true, /* has_gate */
1695 true, /* has_execute */
1696 TV_IPA_FNSPLIT
, /* tv_id */
1697 PROP_cfg
, /* properties_required */
1698 0, /* properties_provided */
1699 0, /* properties_destroyed */
1700 0, /* todo_flags_start */
1701 TODO_verify_all
, /* todo_flags_finish */
1704 class pass_split_functions
: public gimple_opt_pass
1707 pass_split_functions (gcc::context
*ctxt
)
1708 : gimple_opt_pass (pass_data_split_functions
, ctxt
)
1711 /* opt_pass methods: */
1712 bool gate () { return gate_split_functions (); }
1713 unsigned int execute () { return execute_split_functions (); }
1715 }; // class pass_split_functions
1720 make_pass_split_functions (gcc::context
*ctxt
)
1722 return new pass_split_functions (ctxt
);
1725 /* Gate feedback driven function splitting pass.
1726 We don't need to split when profiling at all, we are producing
1727 lousy code anyway. */
1730 gate_feedback_split_functions (void)
1732 return (flag_partial_inlining
1733 && flag_branch_probabilities
);
1736 /* Execute function splitting pass. */
1739 execute_feedback_split_functions (void)
1741 unsigned int retval
= execute_split_functions ();
1743 retval
|= TODO_rebuild_cgraph_edges
;
1749 const pass_data pass_data_feedback_split_functions
=
1751 GIMPLE_PASS
, /* type */
1752 "feedback_fnsplit", /* name */
1753 OPTGROUP_NONE
, /* optinfo_flags */
1754 true, /* has_gate */
1755 true, /* has_execute */
1756 TV_IPA_FNSPLIT
, /* tv_id */
1757 PROP_cfg
, /* properties_required */
1758 0, /* properties_provided */
1759 0, /* properties_destroyed */
1760 0, /* todo_flags_start */
1761 TODO_verify_all
, /* todo_flags_finish */
1764 class pass_feedback_split_functions
: public gimple_opt_pass
1767 pass_feedback_split_functions (gcc::context
*ctxt
)
1768 : gimple_opt_pass (pass_data_feedback_split_functions
, ctxt
)
1771 /* opt_pass methods: */
1772 bool gate () { return gate_feedback_split_functions (); }
1773 unsigned int execute () { return execute_feedback_split_functions (); }
1775 }; // class pass_feedback_split_functions
1780 make_pass_feedback_split_functions (gcc::context
*ctxt
)
1782 return new pass_feedback_split_functions (ctxt
);