1//===- llvm/CodeGen/MachineBasicBlock.h -------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Collect the sequence of machine instructions for a basic block.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H
14#define LLVM_CODEGEN_MACHINEBASICBLOCK_H
15
16#include "llvm/ADT/GraphTraits.h"
17#include "llvm/ADT/ilist.h"
18#include "llvm/ADT/iterator_range.h"
19#include "llvm/ADT/SparseBitVector.h"
20#include "llvm/CodeGen/MachineInstr.h"
21#include "llvm/CodeGen/MachineInstrBundleIterator.h"
22#include "llvm/IR/DebugLoc.h"
23#include "llvm/MC/LaneBitmask.h"
24#include "llvm/Support/BranchProbability.h"
25#include <cassert>
26#include <cstdint>
27#include <functional>
28#include <iterator>
29#include <string>
30#include <vector>
31
32namespace llvm {
33
34class BasicBlock;
35class MachineFunction;
36class MCSymbol;
37class ModuleSlotTracker;
38class Pass;
39class Printable;
40class SlotIndexes;
41class StringRef;
42class raw_ostream;
43class LiveIntervals;
44class TargetRegisterClass;
45class TargetRegisterInfo;
46
47// This structure uniquely identifies a basic block section.
48// Possible values are
49// {Type: Default, Number: (unsigned)} (These are regular section IDs)
50// {Type: Exception, Number: 0} (ExceptionSectionID)
51// {Type: Cold, Number: 0} (ColdSectionID)
52struct MBBSectionID {
53 enum SectionType {
54 Default = 0, // Regular section (these sections are distinguished by the
55 // Number field).
56 Exception, // Special section type for exception handling blocks
57 Cold, // Special section type for cold blocks
58 } Type;
59 unsigned Number;
60
61 MBBSectionID(unsigned N) : Type(Default), Number(N) {}
62
63 // Special unique sections for cold and exception blocks.
64 const static MBBSectionID ColdSectionID;
65 const static MBBSectionID ExceptionSectionID;
66
67 bool operator==(const MBBSectionID &Other) const {
68 return Type == Other.Type && Number == Other.Number;
69 }
70
71 bool operator!=(const MBBSectionID &Other) const { return !(*this == Other); }
72
73private:
74 // This is only used to construct the special cold and exception sections.
75 MBBSectionID(SectionType T) : Type(T), Number(0) {}
76};
77
78template <> struct ilist_traits<MachineInstr> {
79private:
80 friend class MachineBasicBlock; // Set by the owning MachineBasicBlock.
81
82 MachineBasicBlock *Parent;
83
84 using instr_iterator =
85 simple_ilist<MachineInstr, ilist_sentinel_tracking<true>>::iterator;
86
87public:
88 void addNodeToList(MachineInstr *N);
89 void removeNodeFromList(MachineInstr *N);
90 void transferNodesFromList(ilist_traits &FromList, instr_iterator First,
91 instr_iterator Last);
92 void deleteNode(MachineInstr *MI);
93};
94
95class MachineBasicBlock
96 : public ilist_node_with_parent<MachineBasicBlock, MachineFunction> {
97public:
98 /// Pair of physical register and lane mask.
99 /// This is not simply a std::pair typedef because the members should be named
100 /// clearly as they both have an integer type.
101 struct RegisterMaskPair {
102 public:
103 MCPhysReg PhysReg;
104 LaneBitmask LaneMask;
105
106 RegisterMaskPair(MCPhysReg PhysReg, LaneBitmask LaneMask)
107 : PhysReg(PhysReg), LaneMask(LaneMask) {}
108 };
109
110private:
111 using Instructions = ilist<MachineInstr, ilist_sentinel_tracking<true>>;
112
113 Instructions Insts;
114 const BasicBlock *BB;
115 int Number;
116 MachineFunction *xParent;
117
118 /// Keep track of the predecessor / successor basic blocks.
119 std::vector<MachineBasicBlock *> Predecessors;
120 std::vector<MachineBasicBlock *> Successors;
121
122 /// Keep track of the probabilities to the successors. This vector has the
123 /// same order as Successors, or it is empty if we don't use it (disable
124 /// optimization).
125 std::vector<BranchProbability> Probs;
126 using probability_iterator = std::vector<BranchProbability>::iterator;
127 using const_probability_iterator =
128 std::vector<BranchProbability>::const_iterator;
129
130 Optional<uint64_t> IrrLoopHeaderWeight;
131
132 /// Keep track of the physical registers that are livein of the basicblock.
133 using LiveInVector = std::vector<RegisterMaskPair>;
134 LiveInVector LiveIns;
135
136 /// Alignment of the basic block. One if the basic block does not need to be
137 /// aligned.
138 Align Alignment;
139
140 /// Indicate that this basic block is entered via an exception handler.
141 bool IsEHPad = false;
142
143 /// Indicate that this basic block is potentially the target of an indirect
144 /// branch.
145 bool AddressTaken = false;
146
147 /// Indicate that this basic block needs its symbol be emitted regardless of
148 /// whether the flow just falls-through to it.
149 bool LabelMustBeEmitted = false;
150
151 /// Indicate that this basic block is the entry block of an EH scope, i.e.,
152 /// the block that used to have a catchpad or cleanuppad instruction in the
153 /// LLVM IR.
154 bool IsEHScopeEntry = false;
155
156 /// Indicates if this is a target block of a catchret.
157 bool IsEHCatchretTarget = false;
158
159 /// Indicate that this basic block is the entry block of an EH funclet.
160 bool IsEHFuncletEntry = false;
161
162 /// Indicate that this basic block is the entry block of a cleanup funclet.
163 bool IsCleanupFuncletEntry = false;
164
165 /// With basic block sections, this stores the Section ID of the basic block.
166 MBBSectionID SectionID{0};
167
168 // Indicate that this basic block begins a section.
169 bool IsBeginSection = false;
170
171 // Indicate that this basic block ends a section.
172 bool IsEndSection = false;
173
174 /// Indicate that this basic block is the indirect dest of an INLINEASM_BR.
175 bool IsInlineAsmBrIndirectTarget = false;
176
177 /// since getSymbol is a relatively heavy-weight operation, the symbol
178 /// is only computed once and is cached.
179 mutable MCSymbol *CachedMCSymbol = nullptr;
180
181 /// Cached MCSymbol for this block (used if IsEHCatchRetTarget).
182 mutable MCSymbol *CachedEHCatchretMCSymbol = nullptr;
183
184 /// Marks the end of the basic block. Used during basic block sections to
185 /// calculate the size of the basic block, or the BB section ending with it.
186 mutable MCSymbol *CachedEndMCSymbol = nullptr;
187
188 // Intrusive list support
189 MachineBasicBlock() = default;
190
191 explicit MachineBasicBlock(MachineFunction &MF, const BasicBlock *BB);
192
193 ~MachineBasicBlock();
194
195 // MachineBasicBlocks are allocated and owned by MachineFunction.
196 friend class MachineFunction;
197
198public:
199 /// Return the LLVM basic block that this instance corresponded to originally.
200 /// Note that this may be NULL if this instance does not correspond directly
201 /// to an LLVM basic block.
202 const BasicBlock *getBasicBlock() const { return BB; }
203
204 /// Return the name of the corresponding LLVM basic block, or an empty string.
205 StringRef getName() const;
206
207 /// Return a formatted string to identify this block and its parent function.
208 std::string getFullName() const;
209
210 /// Test whether this block is potentially the target of an indirect branch.
211 bool hasAddressTaken() const { return AddressTaken; }
212
213 /// Set this block to reflect that it potentially is the target of an indirect
214 /// branch.
215 void setHasAddressTaken() { AddressTaken = true; }
216
217 /// Test whether this block must have its label emitted.
218 bool hasLabelMustBeEmitted() const { return LabelMustBeEmitted; }
219
220 /// Set this block to reflect that, regardless how we flow to it, we need
221 /// its label be emitted.
222 void setLabelMustBeEmitted() { LabelMustBeEmitted = true; }
223
224 /// Return the MachineFunction containing this basic block.
225 const MachineFunction *getParent() const { return xParent; }
226 MachineFunction *getParent() { return xParent; }
227
228 using instr_iterator = Instructions::iterator;
229 using const_instr_iterator = Instructions::const_iterator;
230 using reverse_instr_iterator = Instructions::reverse_iterator;
231 using const_reverse_instr_iterator = Instructions::const_reverse_iterator;
232
233 using iterator = MachineInstrBundleIterator<MachineInstr>;
234 using const_iterator = MachineInstrBundleIterator<const MachineInstr>;
235 using reverse_iterator = MachineInstrBundleIterator<MachineInstr, true>;
236 using const_reverse_iterator =
237 MachineInstrBundleIterator<const MachineInstr, true>;
238
239 unsigned size() const { return (unsigned)Insts.size(); }
240 bool empty() const { return Insts.empty(); }
241
242 MachineInstr &instr_front() { return Insts.front(); }
243 MachineInstr &instr_back() { return Insts.back(); }
244 const MachineInstr &instr_front() const { return Insts.front(); }
245 const MachineInstr &instr_back() const { return Insts.back(); }
246
247 MachineInstr &front() { return Insts.front(); }
248 MachineInstr &back() { return *--end(); }
249 const MachineInstr &front() const { return Insts.front(); }
250 const MachineInstr &back() const { return *--end(); }
251
252 instr_iterator instr_begin() { return Insts.begin(); }
253 const_instr_iterator instr_begin() const { return Insts.begin(); }
254 instr_iterator instr_end() { return Insts.end(); }
255 const_instr_iterator instr_end() const { return Insts.end(); }
256 reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); }
257 const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); }
258 reverse_instr_iterator instr_rend () { return Insts.rend(); }
259 const_reverse_instr_iterator instr_rend () const { return Insts.rend(); }
260
261 using instr_range = iterator_range<instr_iterator>;
262 using const_instr_range = iterator_range<const_instr_iterator>;
263 instr_range instrs() { return instr_range(instr_begin(), instr_end()); }
264 const_instr_range instrs() const {
265 return const_instr_range(instr_begin(), instr_end());
266 }
267
268 iterator begin() { return instr_begin(); }
269 const_iterator begin() const { return instr_begin(); }
270 iterator end () { return instr_end(); }
271 const_iterator end () const { return instr_end(); }
272 reverse_iterator rbegin() {
273 return reverse_iterator::getAtBundleBegin(instr_rbegin());
274 }
275 const_reverse_iterator rbegin() const {
276 return const_reverse_iterator::getAtBundleBegin(instr_rbegin());
277 }
278 reverse_iterator rend() { return reverse_iterator(instr_rend()); }
279 const_reverse_iterator rend() const {
280 return const_reverse_iterator(instr_rend());
281 }
282
283 /// Support for MachineInstr::getNextNode().
284 static Instructions MachineBasicBlock::*getSublistAccess(MachineInstr *) {
285 return &MachineBasicBlock::Insts;
286 }
287
288 inline iterator_range<iterator> terminators() {
289 return make_range(getFirstTerminator(), end());
290 }
291 inline iterator_range<const_iterator> terminators() const {
292 return make_range(getFirstTerminator(), end());
293 }
294
295 /// Returns a range that iterates over the phis in the basic block.
296 inline iterator_range<iterator> phis() {
297 return make_range(begin(), getFirstNonPHI());
298 }
299 inline iterator_range<const_iterator> phis() const {
300 return const_cast<MachineBasicBlock *>(this)->phis();
301 }
302
303 // Machine-CFG iterators
304 using pred_iterator = std::vector<MachineBasicBlock *>::iterator;
305 using const_pred_iterator = std::vector<MachineBasicBlock *>::const_iterator;
306 using succ_iterator = std::vector<MachineBasicBlock *>::iterator;
307 using const_succ_iterator = std::vector<MachineBasicBlock *>::const_iterator;
308 using pred_reverse_iterator =
309 std::vector<MachineBasicBlock *>::reverse_iterator;
310 using const_pred_reverse_iterator =
311 std::vector<MachineBasicBlock *>::const_reverse_iterator;
312 using succ_reverse_iterator =
313 std::vector<MachineBasicBlock *>::reverse_iterator;
314 using const_succ_reverse_iterator =
315 std::vector<MachineBasicBlock *>::const_reverse_iterator;
316 pred_iterator pred_begin() { return Predecessors.begin(); }
317 const_pred_iterator pred_begin() const { return Predecessors.begin(); }
318 pred_iterator pred_end() { return Predecessors.end(); }
319 const_pred_iterator pred_end() const { return Predecessors.end(); }
320 pred_reverse_iterator pred_rbegin()
321 { return Predecessors.rbegin();}
322 const_pred_reverse_iterator pred_rbegin() const
323 { return Predecessors.rbegin();}
324 pred_reverse_iterator pred_rend()
325 { return Predecessors.rend(); }
326 const_pred_reverse_iterator pred_rend() const
327 { return Predecessors.rend(); }
328 unsigned pred_size() const {
329 return (unsigned)Predecessors.size();
330 }
331 bool pred_empty() const { return Predecessors.empty(); }
332 succ_iterator succ_begin() { return Successors.begin(); }
333 const_succ_iterator succ_begin() const { return Successors.begin(); }
334 succ_iterator succ_end() { return Successors.end(); }
335 const_succ_iterator succ_end() const { return Successors.end(); }
336 succ_reverse_iterator succ_rbegin()
337 { return Successors.rbegin(); }
338 const_succ_reverse_iterator succ_rbegin() const
339 { return Successors.rbegin(); }
340 succ_reverse_iterator succ_rend()
341 { return Successors.rend(); }
342 const_succ_reverse_iterator succ_rend() const
343 { return Successors.rend(); }
344 unsigned succ_size() const {
345 return (unsigned)Successors.size();
346 }
347 bool succ_empty() const { return Successors.empty(); }
348
349 inline iterator_range<pred_iterator> predecessors() {
350 return make_range(pred_begin(), pred_end());
351 }
352 inline iterator_range<const_pred_iterator> predecessors() const {
353 return make_range(pred_begin(), pred_end());
354 }
355 inline iterator_range<succ_iterator> successors() {
356 return make_range(succ_begin(), succ_end());
357 }
358 inline iterator_range<const_succ_iterator> successors() const {
359 return make_range(succ_begin(), succ_end());
360 }
361
362 // LiveIn management methods.
363
364 /// Adds the specified register as a live in. Note that it is an error to add
365 /// the same register to the same set more than once unless the intention is
366 /// to call sortUniqueLiveIns after all registers are added.
367 void addLiveIn(MCRegister PhysReg,
368 LaneBitmask LaneMask = LaneBitmask::getAll()) {
369 LiveIns.push_back(RegisterMaskPair(PhysReg, LaneMask));
370 }
371 void addLiveIn(const RegisterMaskPair &RegMaskPair) {
372 LiveIns.push_back(RegMaskPair);
373 }
374
375 /// Sorts and uniques the LiveIns vector. It can be significantly faster to do
376 /// this than repeatedly calling isLiveIn before calling addLiveIn for every
377 /// LiveIn insertion.
378 void sortUniqueLiveIns();
379
380 /// Clear live in list.
381 void clearLiveIns();
382
383 /// Add PhysReg as live in to this block, and ensure that there is a copy of
384 /// PhysReg to a virtual register of class RC. Return the virtual register
385 /// that is a copy of the live in PhysReg.
386 Register addLiveIn(MCRegister PhysReg, const TargetRegisterClass *RC);
387
388 /// Remove the specified register from the live in set.
389 void removeLiveIn(MCPhysReg Reg,
390 LaneBitmask LaneMask = LaneBitmask::getAll());
391
392 /// Return true if the specified register is in the live in set.
393 bool isLiveIn(MCPhysReg Reg,
394 LaneBitmask LaneMask = LaneBitmask::getAll()) const;
395
396 // Iteration support for live in sets. These sets are kept in sorted
397 // order by their register number.
398 using livein_iterator = LiveInVector::const_iterator;
399#ifndef NDEBUG
400 /// Unlike livein_begin, this method does not check that the liveness
401 /// information is accurate. Still for debug purposes it may be useful
402 /// to have iterators that won't assert if the liveness information
403 /// is not current.
404 livein_iterator livein_begin_dbg() const { return LiveIns.begin(); }
405 iterator_range<livein_iterator> liveins_dbg() const {
406 return make_range(livein_begin_dbg(), livein_end());
407 }
408#endif
409 livein_iterator livein_begin() const;
410 livein_iterator livein_end() const { return LiveIns.end(); }
411 bool livein_empty() const { return LiveIns.empty(); }
412 iterator_range<livein_iterator> liveins() const {
413 return make_range(livein_begin(), livein_end());
414 }
415
416 /// Remove entry from the livein set and return iterator to the next.
417 livein_iterator removeLiveIn(livein_iterator I);
418
419 /// Get the clobber mask for the start of this basic block. Funclets use this
420 /// to prevent register allocation across funclet transitions.
421 const uint32_t *getBeginClobberMask(const TargetRegisterInfo *TRI) const;
422
423 /// Get the clobber mask for the end of the basic block.
424 /// \see getBeginClobberMask()
425 const uint32_t *getEndClobberMask(const TargetRegisterInfo *TRI) const;
426
427 /// Return alignment of the basic block.
428 Align getAlignment() const { return Alignment; }
429
430 /// Set alignment of the basic block.
431 void setAlignment(Align A) { Alignment = A; }
432
433 /// Returns true if the block is a landing pad. That is this basic block is
434 /// entered via an exception handler.
435 bool isEHPad() const { return IsEHPad; }
436
437 /// Indicates the block is a landing pad. That is this basic block is entered
438 /// via an exception handler.
439 void setIsEHPad(bool V = true) { IsEHPad = V; }
440
441 bool hasEHPadSuccessor() const;
442
443 /// Returns true if this is the entry block of the function.
444 bool isEntryBlock() const;
445
446 /// Returns true if this is the entry block of an EH scope, i.e., the block
447 /// that used to have a catchpad or cleanuppad instruction in the LLVM IR.
448 bool isEHScopeEntry() const { return IsEHScopeEntry; }
449
450 /// Indicates if this is the entry block of an EH scope, i.e., the block that
451 /// that used to have a catchpad or cleanuppad instruction in the LLVM IR.
452 void setIsEHScopeEntry(bool V = true) { IsEHScopeEntry = V; }
453
454 /// Returns true if this is a target block of a catchret.
455 bool isEHCatchretTarget() const { return IsEHCatchretTarget; }
456
457 /// Indicates if this is a target block of a catchret.
458 void setIsEHCatchretTarget(bool V = true) { IsEHCatchretTarget = V; }
459
460 /// Returns true if this is the entry block of an EH funclet.
461 bool isEHFuncletEntry() const { return IsEHFuncletEntry; }
462
463 /// Indicates if this is the entry block of an EH funclet.
464 void setIsEHFuncletEntry(bool V = true) { IsEHFuncletEntry = V; }
465
466 /// Returns true if this is the entry block of a cleanup funclet.
467 bool isCleanupFuncletEntry() const { return IsCleanupFuncletEntry; }
468
469 /// Indicates if this is the entry block of a cleanup funclet.
470 void setIsCleanupFuncletEntry(bool V = true) { IsCleanupFuncletEntry = V; }
471
472 /// Returns true if this block begins any section.
473 bool isBeginSection() const { return IsBeginSection; }
474
475 /// Returns true if this block ends any section.
476 bool isEndSection() const { return IsEndSection; }
477
478 void setIsBeginSection(bool V = true) { IsBeginSection = V; }
479
480 void setIsEndSection(bool V = true) { IsEndSection = V; }
481
482 /// Returns the section ID of this basic block.
483 MBBSectionID getSectionID() const { return SectionID; }
484
485 /// Returns the unique section ID number of this basic block.
486 unsigned getSectionIDNum() const {
487 return ((unsigned)MBBSectionID::SectionType::Cold) -
488 ((unsigned)SectionID.Type) + SectionID.Number;
489 }
490
491 /// Sets the section ID for this basic block.
492 void setSectionID(MBBSectionID V) { SectionID = V; }
493
494 /// Returns the MCSymbol marking the end of this basic block.
495 MCSymbol *getEndSymbol() const;
496
497 /// Returns true if this block may have an INLINEASM_BR (overestimate, by
498 /// checking if any of the successors are indirect targets of any inlineasm_br
499 /// in the function).
500 bool mayHaveInlineAsmBr() const;
501
502 /// Returns true if this is the indirect dest of an INLINEASM_BR.
503 bool isInlineAsmBrIndirectTarget() const {
504 return IsInlineAsmBrIndirectTarget;
505 }
506
507 /// Indicates if this is the indirect dest of an INLINEASM_BR.
508 void setIsInlineAsmBrIndirectTarget(bool V = true) {
509 IsInlineAsmBrIndirectTarget = V;
510 }
511
512 /// Returns true if it is legal to hoist instructions into this block.
513 bool isLegalToHoistInto() const;
514
515 // Code Layout methods.
516
517 /// Move 'this' block before or after the specified block. This only moves
518 /// the block, it does not modify the CFG or adjust potential fall-throughs at
519 /// the end of the block.
520 void moveBefore(MachineBasicBlock *NewAfter);
521 void moveAfter(MachineBasicBlock *NewBefore);
522
523 /// Returns true if this and MBB belong to the same section.
524 bool sameSection(const MachineBasicBlock *MBB) const {
525 return getSectionID() == MBB->getSectionID();
526 }
527
528 /// Update the terminator instructions in block to account for changes to
529 /// block layout which may have been made. PreviousLayoutSuccessor should be
530 /// set to the block which may have been used as fallthrough before the block
531 /// layout was modified. If the block previously fell through to that block,
532 /// it may now need a branch. If it previously branched to another block, it
533 /// may now be able to fallthrough to the current layout successor.
534 void updateTerminator(MachineBasicBlock *PreviousLayoutSuccessor);
535
536 // Machine-CFG mutators
537
538 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list
539 /// of Succ is automatically updated. PROB parameter is stored in
540 /// Probabilities list. The default probability is set as unknown. Mixing
541 /// known and unknown probabilities in successor list is not allowed. When all
542 /// successors have unknown probabilities, 1 / N is returned as the
543 /// probability for each successor, where N is the number of successors.
544 ///
545 /// Note that duplicate Machine CFG edges are not allowed.
546 void addSuccessor(MachineBasicBlock *Succ,
547 BranchProbability Prob = BranchProbability::getUnknown());
548
549 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list
550 /// of Succ is automatically updated. The probability is not provided because
551 /// BPI is not available (e.g. -O0 is used), in which case edge probabilities
552 /// won't be used. Using this interface can save some space.
553 void addSuccessorWithoutProb(MachineBasicBlock *Succ);
554
555 /// Set successor probability of a given iterator.
556 void setSuccProbability(succ_iterator I, BranchProbability Prob);
557
558 /// Normalize probabilities of all successors so that the sum of them becomes
559 /// one. This is usually done when the current update on this MBB is done, and
560 /// the sum of its successors' probabilities is not guaranteed to be one. The
561 /// user is responsible for the correct use of this function.
562 /// MBB::removeSuccessor() has an option to do this automatically.
563 void normalizeSuccProbs() {
564 BranchProbability::normalizeProbabilities(Probs.begin(), Probs.end());
565 }
566
567 /// Validate successors' probabilities and check if the sum of them is
568 /// approximate one. This only works in DEBUG mode.
569 void validateSuccProbs() const;
570
571 /// Remove successor from the successors list of this MachineBasicBlock. The
572 /// Predecessors list of Succ is automatically updated.
573 /// If NormalizeSuccProbs is true, then normalize successors' probabilities
574 /// after the successor is removed.
575 void removeSuccessor(MachineBasicBlock *Succ,
576 bool NormalizeSuccProbs = false);
577
578 /// Remove specified successor from the successors list of this
579 /// MachineBasicBlock. The Predecessors list of Succ is automatically updated.
580 /// If NormalizeSuccProbs is true, then normalize successors' probabilities
581 /// after the successor is removed.
582 /// Return the iterator to the element after the one removed.
583 succ_iterator removeSuccessor(succ_iterator I,
584 bool NormalizeSuccProbs = false);
585
586 /// Replace successor OLD with NEW and update probability info.
587 void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New);
588
589 /// Copy a successor (and any probability info) from original block to this
590 /// block's. Uses an iterator into the original blocks successors.
591 ///
592 /// This is useful when doing a partial clone of successors. Afterward, the
593 /// probabilities may need to be normalized.
594 void copySuccessor(MachineBasicBlock *Orig, succ_iterator I);
595
596 /// Split the old successor into old plus new and updates the probability
597 /// info.
598 void splitSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New,
599 bool NormalizeSuccProbs = false);
600
601 /// Transfers all the successors from MBB to this machine basic block (i.e.,
602 /// copies all the successors FromMBB and remove all the successors from
603 /// FromMBB).
604 void transferSuccessors(MachineBasicBlock *FromMBB);
605
606 /// Transfers all the successors, as in transferSuccessors, and update PHI
607 /// operands in the successor blocks which refer to FromMBB to refer to this.
608 void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *FromMBB);
609
610 /// move all pseudo probes in this block to the end of /c ToMBB To and tag
611 /// them dangling.
612 void moveAndDanglePseudoProbes(MachineBasicBlock *ToMBB);
613
614 /// Return true if any of the successors have probabilities attached to them.
615 bool hasSuccessorProbabilities() const { return !Probs.empty(); }
616
617 /// Return true if the specified MBB is a predecessor of this block.
618 bool isPredecessor(const MachineBasicBlock *MBB) const;
619
620 /// Return true if the specified MBB is a successor of this block.
621 bool isSuccessor(const MachineBasicBlock *MBB) const;
622
623 /// Return true if the specified MBB will be emitted immediately after this
624 /// block, such that if this block exits by falling through, control will
625 /// transfer to the specified MBB. Note that MBB need not be a successor at
626 /// all, for example if this block ends with an unconditional branch to some
627 /// other block.
628 bool isLayoutSuccessor(const MachineBasicBlock *MBB) const;
629
630 /// Return the fallthrough block if the block can implicitly
631 /// transfer control to the block after it by falling off the end of
632 /// it. This should return null if it can reach the block after
633 /// it, but it uses an explicit branch to do so (e.g., a table
634 /// jump). Non-null return is a conservative answer.
635 MachineBasicBlock *getFallThrough();
636
637 /// Return true if the block can implicitly transfer control to the
638 /// block after it by falling off the end of it. This should return
639 /// false if it can reach the block after it, but it uses an
640 /// explicit branch to do so (e.g., a table jump). True is a
641 /// conservative answer.
642 bool canFallThrough();
643
644 /// Returns a pointer to the first instruction in this block that is not a
645 /// PHINode instruction. When adding instructions to the beginning of the
646 /// basic block, they should be added before the returned value, not before
647 /// the first instruction, which might be PHI.
648 /// Returns end() is there's no non-PHI instruction.
649 iterator getFirstNonPHI();
650
651 /// Return the first instruction in MBB after I that is not a PHI or a label.
652 /// This is the correct point to insert lowered copies at the beginning of a
653 /// basic block that must be before any debugging information.
654 iterator SkipPHIsAndLabels(iterator I);
655
656 /// Return the first instruction in MBB after I that is not a PHI, label or
657 /// debug. This is the correct point to insert copies at the beginning of a
658 /// basic block.
659 iterator SkipPHIsLabelsAndDebug(iterator I, bool SkipPseudoOp = true);
660
661 /// Returns an iterator to the first terminator instruction of this basic
662 /// block. If a terminator does not exist, it returns end().
663 iterator getFirstTerminator();
664 const_iterator getFirstTerminator() const {
665 return const_cast<MachineBasicBlock *>(this)->getFirstTerminator();
666 }
667
668 /// Same getFirstTerminator but it ignores bundles and return an
669 /// instr_iterator instead.
670 instr_iterator getFirstInstrTerminator();
671
672 /// Returns an iterator to the first non-debug instruction in the basic block,
673 /// or end(). Skip any pseudo probe operation if \c SkipPseudoOp is true.
674 /// Pseudo probes are like debug instructions which do not turn into real
675 /// machine code. We try to use the function to skip both debug instructions
676 /// and pseudo probe operations to avoid API proliferation. This should work
677 /// most of the time when considering optimizing the rest of code in the
678 /// block, except for certain cases where pseudo probes are designed to block
679 /// the optimizations. For example, code merge like optimizations are supposed
680 /// to be blocked by pseudo probes for better AutoFDO profile quality.
681 /// Therefore, they should be considered as a valid instruction when this
682 /// function is called in a context of such optimizations. On the other hand,
683 /// \c SkipPseudoOp should be true when it's used in optimizations that
684 /// unlikely hurt profile quality, e.g., without block merging. The default
685 /// value of \c SkipPseudoOp is set to true to maximize code quality in
686 /// general, with an explict false value passed in in a few places like branch
687 /// folding and if-conversion to favor profile quality.
688 iterator getFirstNonDebugInstr(bool SkipPseudoOp = true);
689 const_iterator getFirstNonDebugInstr(bool SkipPseudoOp = true) const {
690 return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr(
691 SkipPseudoOp);
692 }
693
694 /// Returns an iterator to the last non-debug instruction in the basic block,
695 /// or end(). Skip any pseudo operation if \c SkipPseudoOp is true.
696 /// Pseudo probes are like debug instructions which do not turn into real
697 /// machine code. We try to use the function to skip both debug instructions
698 /// and pseudo probe operations to avoid API proliferation. This should work
699 /// most of the time when considering optimizing the rest of code in the
700 /// block, except for certain cases where pseudo probes are designed to block
701 /// the optimizations. For example, code merge like optimizations are supposed
702 /// to be blocked by pseudo probes for better AutoFDO profile quality.
703 /// Therefore, they should be considered as a valid instruction when this
704 /// function is called in a context of such optimizations. On the other hand,
705 /// \c SkipPseudoOp should be true when it's used in optimizations that
706 /// unlikely hurt profile quality, e.g., without block merging. The default
707 /// value of \c SkipPseudoOp is set to true to maximize code quality in
708 /// general, with an explict false value passed in in a few places like branch
709 /// folding and if-conversion to favor profile quality.
710 iterator getLastNonDebugInstr(bool SkipPseudoOp = true);
711 const_iterator getLastNonDebugInstr(bool SkipPseudoOp = true) const {
712 return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr(
713 SkipPseudoOp);
714 }
715
716 /// Convenience function that returns true if the block ends in a return
717 /// instruction.
718 bool isReturnBlock() const {
719 return !empty() && back().isReturn();
720 }
721
722 /// Convenience function that returns true if the bock ends in a EH scope
723 /// return instruction.
724 bool isEHScopeReturnBlock() const {
725 return !empty() && back().isEHScopeReturn();
726 }
727
728 /// Split a basic block into 2 pieces at \p SplitPoint. A new block will be
729 /// inserted after this block, and all instructions after \p SplitInst moved
730 /// to it (\p SplitInst will be in the original block). If \p LIS is provided,
731 /// LiveIntervals will be appropriately updated. \return the newly inserted
732 /// block.
733 ///
734 /// If \p UpdateLiveIns is true, this will ensure the live ins list is
735 /// accurate, including for physreg uses/defs in the original block.
736 MachineBasicBlock *splitAt(MachineInstr &SplitInst, bool UpdateLiveIns = true,
737 LiveIntervals *LIS = nullptr);
738
739 /// Split the critical edge from this block to the given successor block, and
740 /// return the newly created block, or null if splitting is not possible.
741 ///
742 /// This function updates LiveVariables, MachineDominatorTree, and
743 /// MachineLoopInfo, as applicable.
744 MachineBasicBlock *
745 SplitCriticalEdge(MachineBasicBlock *Succ, Pass &P,
746 std::vector<SparseBitVector<>> *LiveInSets = nullptr);
747
748 /// Check if the edge between this block and the given successor \p
749 /// Succ, can be split. If this returns true a subsequent call to
750 /// SplitCriticalEdge is guaranteed to return a valid basic block if
751 /// no changes occurred in the meantime.
752 bool canSplitCriticalEdge(const MachineBasicBlock *Succ) const;
753
754 void pop_front() { Insts.pop_front(); }
755 void pop_back() { Insts.pop_back(); }
756 void push_back(MachineInstr *MI) { Insts.push_back(MI); }
757
758 /// Insert MI into the instruction list before I, possibly inside a bundle.
759 ///
760 /// If the insertion point is inside a bundle, MI will be added to the bundle,
761 /// otherwise MI will not be added to any bundle. That means this function
762 /// alone can't be used to prepend or append instructions to bundles. See
763 /// MIBundleBuilder::insert() for a more reliable way of doing that.
764 instr_iterator insert(instr_iterator I, MachineInstr *M);
765
766 /// Insert a range of instructions into the instruction list before I.
767 template<typename IT>
768 void insert(iterator I, IT S, IT E) {
769 assert((I == end() || I->getParent() == this) &&
770 "iterator points outside of basic block");
771 Insts.insert(I.getInstrIterator(), S, E);
772 }
773
774 /// Insert MI into the instruction list before I.
775 iterator insert(iterator I, MachineInstr *MI) {
776 assert((I == end() || I->getParent() == this) &&
777 "iterator points outside of basic block");
778 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
779 "Cannot insert instruction with bundle flags");
780 return Insts.insert(I.getInstrIterator(), MI);
781 }
782
783 /// Insert MI into the instruction list after I.
784 iterator insertAfter(iterator I, MachineInstr *MI) {
785 assert((I == end() || I->getParent() == this) &&
786 "iterator points outside of basic block");
787 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
788 "Cannot insert instruction with bundle flags");
789 return Insts.insertAfter(I.getInstrIterator(), MI);
790 }
791
792 /// If I is bundled then insert MI into the instruction list after the end of
793 /// the bundle, otherwise insert MI immediately after I.
794 instr_iterator insertAfterBundle(instr_iterator I, MachineInstr *MI) {
795 assert((I == instr_end() || I->getParent() == this) &&
796 "iterator points outside of basic block");
797 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
798 "Cannot insert instruction with bundle flags");
799 while (I->isBundledWithSucc())
800 ++I;
801 return Insts.insertAfter(I, MI);
802 }
803
804 /// Remove an instruction from the instruction list and delete it.
805 ///
806 /// If the instruction is part of a bundle, the other instructions in the
807 /// bundle will still be bundled after removing the single instruction.
808 instr_iterator erase(instr_iterator I);
809
810 /// Remove an instruction from the instruction list and delete it.
811 ///
812 /// If the instruction is part of a bundle, the other instructions in the
813 /// bundle will still be bundled after removing the single instruction.
814 instr_iterator erase_instr(MachineInstr *I) {
815 return erase(instr_iterator(I));
816 }
817
818 /// Remove a range of instructions from the instruction list and delete them.
819 iterator erase(iterator I, iterator E) {
820 return Insts.erase(I.getInstrIterator(), E.getInstrIterator());
821 }
822
823 /// Remove an instruction or bundle from the instruction list and delete it.
824 ///
825 /// If I points to a bundle of instructions, they are all erased.
826 iterator erase(iterator I) {
827 return erase(I, std::next(I));
828 }
829
830 /// Remove an instruction from the instruction list and delete it.
831 ///
832 /// If I is the head of a bundle of instructions, the whole bundle will be
833 /// erased.
834 iterator erase(MachineInstr *I) {
835 return erase(iterator(I));
836 }
837
838 /// Remove the unbundled instruction from the instruction list without
839 /// deleting it.
840 ///
841 /// This function can not be used to remove bundled instructions, use
842 /// remove_instr to remove individual instructions from a bundle.
843 MachineInstr *remove(MachineInstr *I) {
844 assert(!I->isBundled() && "Cannot remove bundled instructions");
845 return Insts.remove(instr_iterator(I));
846 }
847
848 /// Remove the possibly bundled instruction from the instruction list
849 /// without deleting it.
850 ///
851 /// If the instruction is part of a bundle, the other instructions in the
852 /// bundle will still be bundled after removing the single instruction.
853 MachineInstr *remove_instr(MachineInstr *I);
854
855 void clear() {
856 Insts.clear();
857 }
858
859 /// Take an instruction from MBB 'Other' at the position From, and insert it
860 /// into this MBB right before 'Where'.
861 ///
862 /// If From points to a bundle of instructions, the whole bundle is moved.
863 void splice(iterator Where, MachineBasicBlock *Other, iterator From) {
864 // The range splice() doesn't allow noop moves, but this one does.
865 if (Where != From)
866 splice(Where, Other, From, std::next(From));
867 }
868
869 /// Take a block of instructions from MBB 'Other' in the range [From, To),
870 /// and insert them into this MBB right before 'Where'.
871 ///
872 /// The instruction at 'Where' must not be included in the range of
873 /// instructions to move.
874 void splice(iterator Where, MachineBasicBlock *Other,
875 iterator From, iterator To) {
876 Insts.splice(Where.getInstrIterator(), Other->Insts,
877 From.getInstrIterator(), To.getInstrIterator());
878 }
879
880 /// This method unlinks 'this' from the containing function, and returns it,
881 /// but does not delete it.
882 MachineBasicBlock *removeFromParent();
883
884 /// This method unlinks 'this' from the containing function and deletes it.
885 void eraseFromParent();
886
887 /// Given a machine basic block that branched to 'Old', change the code and
888 /// CFG so that it branches to 'New' instead.
889 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
890
891 /// Update all phi nodes in this basic block to refer to basic block \p New
892 /// instead of basic block \p Old.
893 void replacePhiUsesWith(MachineBasicBlock *Old, MachineBasicBlock *New);
894
895 /// Find the next valid DebugLoc starting at MBBI, skipping any DBG_VALUE
896 /// and DBG_LABEL instructions. Return UnknownLoc if there is none.
897 DebugLoc findDebugLoc(instr_iterator MBBI);
898 DebugLoc findDebugLoc(iterator MBBI) {
899 return findDebugLoc(MBBI.getInstrIterator());
900 }
901
902 /// Has exact same behavior as @ref findDebugLoc (it also
903 /// searches from the first to the last MI of this MBB) except
904 /// that this takes reverse iterator.
905 DebugLoc rfindDebugLoc(reverse_instr_iterator MBBI);
906 DebugLoc rfindDebugLoc(reverse_iterator MBBI) {
907 return rfindDebugLoc(MBBI.getInstrIterator());
908 }
909
910 /// Find the previous valid DebugLoc preceding MBBI, skipping and DBG_VALUE
911 /// instructions. Return UnknownLoc if there is none.
912 DebugLoc findPrevDebugLoc(instr_iterator MBBI);
913 DebugLoc findPrevDebugLoc(iterator MBBI) {
914 return findPrevDebugLoc(MBBI.getInstrIterator());
915 }
916
917 /// Has exact same behavior as @ref findPrevDebugLoc (it also
918 /// searches from the last to the first MI of this MBB) except
919 /// that this takes reverse iterator.
920 DebugLoc rfindPrevDebugLoc(reverse_instr_iterator MBBI);
921 DebugLoc rfindPrevDebugLoc(reverse_iterator MBBI) {
922 return rfindPrevDebugLoc(MBBI.getInstrIterator());
923 }
924
925 /// Find and return the merged DebugLoc of the branch instructions of the
926 /// block. Return UnknownLoc if there is none.
927 DebugLoc findBranchDebugLoc();
928
929 /// Possible outcome of a register liveness query to computeRegisterLiveness()
930 enum LivenessQueryResult {
931 LQR_Live, ///< Register is known to be (at least partially) live.
932 LQR_Dead, ///< Register is known to be fully dead.
933 LQR_Unknown ///< Register liveness not decidable from local neighborhood.
934 };
935
936 /// Return whether (physical) register \p Reg has been defined and not
937 /// killed as of just before \p Before.
938 ///
939 /// Search is localised to a neighborhood of \p Neighborhood instructions
940 /// before (searching for defs or kills) and \p Neighborhood instructions
941 /// after (searching just for defs) \p Before.
942 ///
943 /// \p Reg must be a physical register.
944 LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI,
945 MCRegister Reg,
946 const_iterator Before,
947 unsigned Neighborhood = 10) const;
948
949 // Debugging methods.
950 void dump() const;
951 void print(raw_ostream &OS, const SlotIndexes * = nullptr,
952 bool IsStandalone = true) const;
953 void print(raw_ostream &OS, ModuleSlotTracker &MST,
954 const SlotIndexes * = nullptr, bool IsStandalone = true) const;
955
956 enum PrintNameFlag {
957 PrintNameIr = (1 << 0), ///< Add IR name where available
958 PrintNameAttributes = (1 << 1), ///< Print attributes
959 };
960
961 void printName(raw_ostream &os, unsigned printNameFlags = PrintNameIr,
962 ModuleSlotTracker *moduleSlotTracker = nullptr) const;
963
964 // Printing method used by LoopInfo.
965 void printAsOperand(raw_ostream &OS, bool PrintType = true) const;
966
967 /// MachineBasicBlocks are uniquely numbered at the function level, unless
968 /// they're not in a MachineFunction yet, in which case this will return -1.
969 int getNumber() const { return Number; }
970 void setNumber(int N) { Number = N; }
971
972 /// Return the MCSymbol for this basic block.
973 MCSymbol *getSymbol() const;
974
975 /// Return the EHCatchret Symbol for this basic block.
976 MCSymbol *getEHCatchretSymbol() const;
977
978 Optional<uint64_t> getIrrLoopHeaderWeight() const {
979 return IrrLoopHeaderWeight;
980 }
981
982 void setIrrLoopHeaderWeight(uint64_t Weight) {
983 IrrLoopHeaderWeight = Weight;
984 }
985
986private:
987 /// Return probability iterator corresponding to the I successor iterator.
988 probability_iterator getProbabilityIterator(succ_iterator I);
989 const_probability_iterator
990 getProbabilityIterator(const_succ_iterator I) const;
991
992 friend class MachineBranchProbabilityInfo;
993 friend class MIPrinter;
994
995 /// Return probability of the edge from this block to MBB. This method should
996 /// NOT be called directly, but by using getEdgeProbability method from
997 /// MachineBranchProbabilityInfo class.
998 BranchProbability getSuccProbability(const_succ_iterator Succ) const;
999
1000 // Methods used to maintain doubly linked list of blocks...
1001 friend struct ilist_callback_traits<MachineBasicBlock>;
1002
1003 // Machine-CFG mutators
1004
1005 /// Add Pred as a predecessor of this MachineBasicBlock. Don't do this
1006 /// unless you know what you're doing, because it doesn't update Pred's
1007 /// successors list. Use Pred->addSuccessor instead.
1008 void addPredecessor(MachineBasicBlock *Pred);
1009
1010 /// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this
1011 /// unless you know what you're doing, because it doesn't update Pred's
1012 /// successors list. Use Pred->removeSuccessor instead.
1013 void removePredecessor(MachineBasicBlock *Pred);
1014};
1015
1016raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB);
1017
1018/// Prints a machine basic block reference.
1019///
1020/// The format is:
1021/// %bb.5 - a machine basic block with MBB.getNumber() == 5.
1022///
1023/// Usage: OS << printMBBReference(MBB) << '\n';
1024Printable printMBBReference(const MachineBasicBlock &MBB);
1025
1026// This is useful when building IndexedMaps keyed on basic block pointers.
1027struct MBB2NumberFunctor {
1028 using argument_type = const MachineBasicBlock *;
1029 unsigned operator()(const MachineBasicBlock *MBB) const {
1030 return MBB->getNumber();
1031 }
1032};
1033
1034//===--------------------------------------------------------------------===//
1035// GraphTraits specializations for machine basic block graphs (machine-CFGs)
1036//===--------------------------------------------------------------------===//
1037
1038// Provide specializations of GraphTraits to be able to treat a
1039// MachineFunction as a graph of MachineBasicBlocks.
1040//
1041
1042template <> struct GraphTraits<MachineBasicBlock *> {
1043 using NodeRef = MachineBasicBlock *;
1044 using ChildIteratorType = MachineBasicBlock::succ_iterator;
1045
1046 static NodeRef getEntryNode(MachineBasicBlock *BB) { return BB; }
1047 static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); }
1048 static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); }
1049};
1050
1051template <> struct GraphTraits<const MachineBasicBlock *> {
1052 using NodeRef = const MachineBasicBlock *;
1053 using ChildIteratorType = MachineBasicBlock::const_succ_iterator;
1054
1055 static NodeRef getEntryNode(const MachineBasicBlock *BB) { return BB; }
1056 static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); }
1057 static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); }
1058};
1059
1060// Provide specializations of GraphTraits to be able to treat a
1061// MachineFunction as a graph of MachineBasicBlocks and to walk it
1062// in inverse order. Inverse order for a function is considered
1063// to be when traversing the predecessor edges of a MBB
1064// instead of the successor edges.
1065//
1066template <> struct GraphTraits<Inverse<MachineBasicBlock*>> {
1067 using NodeRef = MachineBasicBlock *;
1068 using ChildIteratorType = MachineBasicBlock::pred_iterator;
1069
1070 static NodeRef getEntryNode(Inverse<MachineBasicBlock *> G) {
1071 return G.Graph;
1072 }
1073
1074 static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); }
1075 static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); }
1076};
1077
1078template <> struct GraphTraits<Inverse<const MachineBasicBlock*>> {
1079 using NodeRef = const MachineBasicBlock *;
1080 using ChildIteratorType = MachineBasicBlock::const_pred_iterator;
1081
1082 static NodeRef getEntryNode(Inverse<const MachineBasicBlock *> G) {
1083 return G.Graph;
1084 }
1085
1086 static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); }
1087 static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); }
1088};
1089
1090/// MachineInstrSpan provides an interface to get an iteration range
1091/// containing the instruction it was initialized with, along with all
1092/// those instructions inserted prior to or following that instruction
1093/// at some point after the MachineInstrSpan is constructed.
1094class MachineInstrSpan {
1095 MachineBasicBlock &MBB;
1096 MachineBasicBlock::iterator I, B, E;
1097
1098public:
1099 MachineInstrSpan(MachineBasicBlock::iterator I, MachineBasicBlock *BB)
1100 : MBB(*BB), I(I), B(I == MBB.begin() ? MBB.end() : std::prev(I)),
1101 E(std::next(I)) {
1102 assert(I == BB->end() || I->getParent() == BB);
1103 }
1104
1105 MachineBasicBlock::iterator begin() {
1106 return B == MBB.end() ? MBB.begin() : std::next(B);
1107 }
1108 MachineBasicBlock::iterator end() { return E; }
1109 bool empty() { return begin() == end(); }
1110
1111 MachineBasicBlock::iterator getInitial() { return I; }
1112};
1113
1114/// Increment \p It until it points to a non-debug instruction or to \p End
1115/// and return the resulting iterator. This function should only be used
1116/// MachineBasicBlock::{iterator, const_iterator, instr_iterator,
1117/// const_instr_iterator} and the respective reverse iterators.
1118template <typename IterT>
1119inline IterT skipDebugInstructionsForward(IterT It, IterT End,
1120 bool SkipPseudoOp = true) {
1121 while (It != End &&
1122 (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe())))
1123 ++It;
1124 return It;
1125}
1126
1127/// Decrement \p It until it points to a non-debug instruction or to \p Begin
1128/// and return the resulting iterator. This function should only be used
1129/// MachineBasicBlock::{iterator, const_iterator, instr_iterator,
1130/// const_instr_iterator} and the respective reverse iterators.
1131template <class IterT>
1132inline IterT skipDebugInstructionsBackward(IterT It, IterT Begin,
1133 bool SkipPseudoOp = true) {
1134 while (It != Begin &&
1135 (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe())))
1136 --It;
1137 return It;
1138}
1139
1140/// Increment \p It, then continue incrementing it while it points to a debug
1141/// instruction. A replacement for std::next.
1142template <typename IterT>
1143inline IterT next_nodbg(IterT It, IterT End, bool SkipPseudoOp = true) {
1144 return skipDebugInstructionsForward(std::next(It), End, SkipPseudoOp);
1145}
1146
1147/// Decrement \p It, then continue decrementing it while it points to a debug
1148/// instruction. A replacement for std::prev.
1149template <typename IterT>
1150inline IterT prev_nodbg(IterT It, IterT Begin, bool SkipPseudoOp = true) {
1151 return skipDebugInstructionsBackward(std::prev(It), Begin, SkipPseudoOp);
1152}
1153
1154/// Construct a range iterator which begins at \p It and moves forwards until
1155/// \p End is reached, skipping any debug instructions.
1156template <typename IterT>
1157inline auto instructionsWithoutDebug(IterT It, IterT End,
1158 bool SkipPseudoOp = true) {
1159 return make_filter_range(make_range(It, End), [=](const MachineInstr &MI) {
1160 return !MI.isDebugInstr() && !(SkipPseudoOp && MI.isPseudoProbe());
1161 });
1162}
1163
1164} // end namespace llvm
1165
1166#endif // LLVM_CODEGEN_MACHINEBASICBLOCK_H
1167