LLVM 20.0.0git
SSAUpdater.cpp
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1//===- SSAUpdater.cpp - Unstructured SSA Update Tool ----------------------===//
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// This file implements the SSAUpdater class.
10//
11//===----------------------------------------------------------------------===//
12
14#include "llvm/ADT/DenseMap.h"
15#include "llvm/ADT/STLExtras.h"
19#include "llvm/IR/BasicBlock.h"
20#include "llvm/IR/CFG.h"
21#include "llvm/IR/Constants.h"
22#include "llvm/IR/DebugInfo.h"
23#include "llvm/IR/DebugLoc.h"
24#include "llvm/IR/Instruction.h"
26#include "llvm/IR/Use.h"
27#include "llvm/IR/Value.h"
29#include "llvm/Support/Debug.h"
32#include <cassert>
33#include <utility>
34
35using namespace llvm;
36
37#define DEBUG_TYPE "ssaupdater"
38
40
42 return *static_cast<AvailableValsTy*>(AV);
43}
44
46 : InsertedPHIs(NewPHI) {}
47
49 delete static_cast<AvailableValsTy*>(AV);
50}
51
53 if (!AV)
54 AV = new AvailableValsTy();
55 else
57 ProtoType = Ty;
58 ProtoName = std::string(Name);
59}
60
62 return getAvailableVals(AV).count(BB);
63}
64
66 return getAvailableVals(AV).lookup(BB);
67}
68
70 assert(ProtoType && "Need to initialize SSAUpdater");
71 assert(ProtoType == V->getType() &&
72 "All rewritten values must have the same type");
73 getAvailableVals(AV)[BB] = V;
74}
75
78 unsigned PHINumValues = PHI->getNumIncomingValues();
79 if (PHINumValues != ValueMapping.size())
80 return false;
81
82 // Scan the phi to see if it matches.
83 for (unsigned i = 0, e = PHINumValues; i != e; ++i)
84 if (ValueMapping[PHI->getIncomingBlock(i)] !=
85 PHI->getIncomingValue(i)) {
86 return false;
87 }
88
89 return true;
90}
91
93 Value *Res = GetValueAtEndOfBlockInternal(BB);
94 return Res;
95}
96
98 // If there is no definition of the renamed variable in this block, just use
99 // GetValueAtEndOfBlock to do our work.
100 if (!HasValueForBlock(BB))
101 return GetValueAtEndOfBlock(BB);
102
103 // Otherwise, we have the hard case. Get the live-in values for each
104 // predecessor.
106 Value *SingularValue = nullptr;
107
108 // We can get our predecessor info by walking the pred_iterator list, but it
109 // is relatively slow. If we already have PHI nodes in this block, walk one
110 // of them to get the predecessor list instead.
111 if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin())) {
112 for (unsigned i = 0, e = SomePhi->getNumIncomingValues(); i != e; ++i) {
113 BasicBlock *PredBB = SomePhi->getIncomingBlock(i);
114 Value *PredVal = GetValueAtEndOfBlock(PredBB);
115 PredValues.push_back(std::make_pair(PredBB, PredVal));
116
117 // Compute SingularValue.
118 if (i == 0)
119 SingularValue = PredVal;
120 else if (PredVal != SingularValue)
121 SingularValue = nullptr;
122 }
123 } else {
124 bool isFirstPred = true;
125 for (BasicBlock *PredBB : predecessors(BB)) {
126 Value *PredVal = GetValueAtEndOfBlock(PredBB);
127 PredValues.push_back(std::make_pair(PredBB, PredVal));
128
129 // Compute SingularValue.
130 if (isFirstPred) {
131 SingularValue = PredVal;
132 isFirstPred = false;
133 } else if (PredVal != SingularValue)
134 SingularValue = nullptr;
135 }
136 }
137
138 // If there are no predecessors, just return poison.
139 if (PredValues.empty())
140 return PoisonValue::get(ProtoType);
141
142 // Otherwise, if all the merged values are the same, just use it.
143 if (SingularValue)
144 return SingularValue;
145
146 // Otherwise, we do need a PHI: check to see if we already have one available
147 // in this block that produces the right value.
148 if (isa<PHINode>(BB->begin())) {
149 SmallDenseMap<BasicBlock *, Value *, 8> ValueMapping(PredValues.begin(),
150 PredValues.end());
151 for (PHINode &SomePHI : BB->phis()) {
152 if (IsEquivalentPHI(&SomePHI, ValueMapping))
153 return &SomePHI;
154 }
155 }
156
157 // Ok, we have no way out, insert a new one now.
158 PHINode *InsertedPHI =
159 PHINode::Create(ProtoType, PredValues.size(), ProtoName);
160 InsertedPHI->insertBefore(BB->begin());
161
162 // Fill in all the predecessors of the PHI.
163 for (const auto &PredValue : PredValues)
164 InsertedPHI->addIncoming(PredValue.second, PredValue.first);
165
166 // See if the PHI node can be merged to a single value. This can happen in
167 // loop cases when we get a PHI of itself and one other value.
168 if (Value *V =
169 simplifyInstruction(InsertedPHI, BB->getDataLayout())) {
170 InsertedPHI->eraseFromParent();
171 return V;
172 }
173
174 // Set the DebugLoc of the inserted PHI, if available.
175 DebugLoc DL;
176 if (const Instruction *I = BB->getFirstNonPHI())
177 DL = I->getDebugLoc();
178 InsertedPHI->setDebugLoc(DL);
179
180 // If the client wants to know about all new instructions, tell it.
181 if (InsertedPHIs) InsertedPHIs->push_back(InsertedPHI);
182
183 LLVM_DEBUG(dbgs() << " Inserted PHI: " << *InsertedPHI << "\n");
184 return InsertedPHI;
185}
186
188 Instruction *User = cast<Instruction>(U.getUser());
189
190 Value *V;
191 if (PHINode *UserPN = dyn_cast<PHINode>(User))
192 V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U));
193 else
194 V = GetValueInMiddleOfBlock(User->getParent());
195
196 U.set(V);
197}
198
201 SmallVector<DbgVariableRecord *, 4> DbgVariableRecords;
202 llvm::findDbgValues(DbgValues, I, &DbgVariableRecords);
203 for (auto &DbgValue : DbgValues) {
204 if (DbgValue->getParent() == I->getParent())
205 continue;
206 UpdateDebugValue(I, DbgValue);
207 }
208 for (auto &DVR : DbgVariableRecords) {
209 if (DVR->getParent() == I->getParent())
210 continue;
211 UpdateDebugValue(I, DVR);
212 }
213}
214
217 for (auto &DbgValue : DbgValues) {
218 UpdateDebugValue(I, DbgValue);
219 }
220}
221
223 Instruction *I, SmallVectorImpl<DbgVariableRecord *> &DbgVariableRecords) {
224 for (auto &DVR : DbgVariableRecords) {
225 UpdateDebugValue(I, DVR);
226 }
227}
228
229void SSAUpdater::UpdateDebugValue(Instruction *I, DbgValueInst *DbgValue) {
230 BasicBlock *UserBB = DbgValue->getParent();
231 if (HasValueForBlock(UserBB)) {
232 Value *NewVal = GetValueAtEndOfBlock(UserBB);
233 DbgValue->replaceVariableLocationOp(I, NewVal);
234 } else
235 DbgValue->setKillLocation();
236}
237
238void SSAUpdater::UpdateDebugValue(Instruction *I, DbgVariableRecord *DVR) {
239 BasicBlock *UserBB = DVR->getParent();
240 if (HasValueForBlock(UserBB)) {
241 Value *NewVal = GetValueAtEndOfBlock(UserBB);
242 DVR->replaceVariableLocationOp(I, NewVal);
243 } else
244 DVR->setKillLocation();
245}
246
248 Instruction *User = cast<Instruction>(U.getUser());
249
250 Value *V;
251 if (PHINode *UserPN = dyn_cast<PHINode>(User))
252 V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U));
253 else
254 V = GetValueAtEndOfBlock(User->getParent());
255
256 U.set(V);
257}
258
259namespace llvm {
260
261template<>
263public:
265 using ValT = Value *;
266 using PhiT = PHINode;
268
269 static BlkSucc_iterator BlkSucc_begin(BlkT *BB) { return succ_begin(BB); }
270 static BlkSucc_iterator BlkSucc_end(BlkT *BB) { return succ_end(BB); }
271
272 class PHI_iterator {
273 private:
274 PHINode *PHI;
275 unsigned idx;
276
277 public:
278 explicit PHI_iterator(PHINode *P) // begin iterator
279 : PHI(P), idx(0) {}
280 PHI_iterator(PHINode *P, bool) // end iterator
281 : PHI(P), idx(PHI->getNumIncomingValues()) {}
282
283 PHI_iterator &operator++() { ++idx; return *this; }
284 bool operator==(const PHI_iterator& x) const { return idx == x.idx; }
285 bool operator!=(const PHI_iterator& x) const { return !operator==(x); }
286
287 Value *getIncomingValue() { return PHI->getIncomingValue(idx); }
288 BasicBlock *getIncomingBlock() { return PHI->getIncomingBlock(idx); }
289 };
290
291 static PHI_iterator PHI_begin(PhiT *PHI) { return PHI_iterator(PHI); }
292 static PHI_iterator PHI_end(PhiT *PHI) {
293 return PHI_iterator(PHI, true);
294 }
295
296 /// FindPredecessorBlocks - Put the predecessors of Info->BB into the Preds
297 /// vector, set Info->NumPreds, and allocate space in Info->Preds.
300 // We can get our predecessor info by walking the pred_iterator list,
301 // but it is relatively slow. If we already have PHI nodes in this
302 // block, walk one of them to get the predecessor list instead.
303 if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin()))
304 append_range(*Preds, SomePhi->blocks());
305 else
306 append_range(*Preds, predecessors(BB));
307 }
308
309 /// GetPoisonVal - Get a poison value of the same type as the value
310 /// being handled.
311 static Value *GetPoisonVal(BasicBlock *BB, SSAUpdater *Updater) {
312 return PoisonValue::get(Updater->ProtoType);
313 }
314
315 /// CreateEmptyPHI - Create a new PHI instruction in the specified block.
316 /// Reserve space for the operands but do not fill them in yet.
317 static Value *CreateEmptyPHI(BasicBlock *BB, unsigned NumPreds,
318 SSAUpdater *Updater) {
319 PHINode *PHI =
320 PHINode::Create(Updater->ProtoType, NumPreds, Updater->ProtoName);
321 PHI->insertBefore(BB->begin());
322 return PHI;
323 }
324
325 /// AddPHIOperand - Add the specified value as an operand of the PHI for
326 /// the specified predecessor block.
327 static void AddPHIOperand(PHINode *PHI, Value *Val, BasicBlock *Pred) {
328 PHI->addIncoming(Val, Pred);
329 }
330
331 /// ValueIsPHI - Check if a value is a PHI.
332 static PHINode *ValueIsPHI(Value *Val, SSAUpdater *Updater) {
333 return dyn_cast<PHINode>(Val);
334 }
335
336 /// ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source
337 /// operands, i.e., it was just added.
338 static PHINode *ValueIsNewPHI(Value *Val, SSAUpdater *Updater) {
339 PHINode *PHI = ValueIsPHI(Val, Updater);
340 if (PHI && PHI->getNumIncomingValues() == 0)
341 return PHI;
342 return nullptr;
343 }
344
345 /// GetPHIValue - For the specified PHI instruction, return the value
346 /// that it defines.
348 return PHI;
349 }
350};
351
352} // end namespace llvm
353
354/// Check to see if AvailableVals has an entry for the specified BB and if so,
355/// return it. If not, construct SSA form by first calculating the required
356/// placement of PHIs and then inserting new PHIs where needed.
357Value *SSAUpdater::GetValueAtEndOfBlockInternal(BasicBlock *BB) {
358 AvailableValsTy &AvailableVals = getAvailableVals(AV);
359 if (Value *V = AvailableVals[BB])
360 return V;
361
362 SSAUpdaterImpl<SSAUpdater> Impl(this, &AvailableVals, InsertedPHIs);
363 return Impl.GetValue(BB);
364}
365
366//===----------------------------------------------------------------------===//
367// LoadAndStorePromoter Implementation
368//===----------------------------------------------------------------------===//
369
372 SSAUpdater &S, StringRef BaseName) : SSA(S) {
373 if (Insts.empty()) return;
374
375 const Value *SomeVal;
376 if (const LoadInst *LI = dyn_cast<LoadInst>(Insts[0]))
377 SomeVal = LI;
378 else
379 SomeVal = cast<StoreInst>(Insts[0])->getOperand(0);
380
381 if (BaseName.empty())
382 BaseName = SomeVal->getName();
383 SSA.Initialize(SomeVal->getType(), BaseName);
384}
385
387 // First step: bucket up uses of the alloca by the block they occur in.
388 // This is important because we have to handle multiple defs/uses in a block
389 // ourselves: SSAUpdater is purely for cross-block references.
391
392 for (Instruction *User : Insts)
393 UsesByBlock[User->getParent()].push_back(User);
394
395 // Okay, now we can iterate over all the blocks in the function with uses,
396 // processing them. Keep track of which loads are loading a live-in value.
397 // Walk the uses in the use-list order to be determinstic.
398 SmallVector<LoadInst *, 32> LiveInLoads;
399 DenseMap<Value *, Value *> ReplacedLoads;
400
401 for (Instruction *User : Insts) {
402 BasicBlock *BB = User->getParent();
403 TinyPtrVector<Instruction *> &BlockUses = UsesByBlock[BB];
404
405 // If this block has already been processed, ignore this repeat use.
406 if (BlockUses.empty()) continue;
407
408 // Okay, this is the first use in the block. If this block just has a
409 // single user in it, we can rewrite it trivially.
410 if (BlockUses.size() == 1) {
411 // If it is a store, it is a trivial def of the value in the block.
412 if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
413 updateDebugInfo(SI);
414 SSA.AddAvailableValue(BB, SI->getOperand(0));
415 } else if (auto *AI = dyn_cast<AllocaInst>(User)) {
416 // We treat AllocaInst as a store of an getValueToUseForAlloca value.
418 } else {
419 // Otherwise it is a load, queue it to rewrite as a live-in load.
420 LiveInLoads.push_back(cast<LoadInst>(User));
421 }
422 BlockUses.clear();
423 continue;
424 }
425
426 // Otherwise, check to see if this block is all loads.
427 bool HasStore = false;
428 for (Instruction *I : BlockUses) {
429 if (isa<StoreInst>(I) || isa<AllocaInst>(I)) {
430 HasStore = true;
431 break;
432 }
433 }
434
435 // If so, we can queue them all as live in loads. We don't have an
436 // efficient way to tell which on is first in the block and don't want to
437 // scan large blocks, so just add all loads as live ins.
438 if (!HasStore) {
439 for (Instruction *I : BlockUses)
440 LiveInLoads.push_back(cast<LoadInst>(I));
441 BlockUses.clear();
442 continue;
443 }
444
445 // Otherwise, we have mixed loads and stores (or just a bunch of stores).
446 // Since SSAUpdater is purely for cross-block values, we need to determine
447 // the order of these instructions in the block. If the first use in the
448 // block is a load, then it uses the live in value. The last store defines
449 // the live out value. We handle this by doing a linear scan of the block.
450 Value *StoredValue = nullptr;
451 for (Instruction &I : *BB) {
452 if (LoadInst *L = dyn_cast<LoadInst>(&I)) {
453 // If this is a load from an unrelated pointer, ignore it.
454 if (!isInstInList(L, Insts)) continue;
455
456 // If we haven't seen a store yet, this is a live in use, otherwise
457 // use the stored value.
458 if (StoredValue) {
459 replaceLoadWithValue(L, StoredValue);
460 L->replaceAllUsesWith(StoredValue);
461 ReplacedLoads[L] = StoredValue;
462 } else {
463 LiveInLoads.push_back(L);
464 }
465 continue;
466 }
467
468 if (StoreInst *SI = dyn_cast<StoreInst>(&I)) {
469 // If this is a store to an unrelated pointer, ignore it.
470 if (!isInstInList(SI, Insts)) continue;
471 updateDebugInfo(SI);
472
473 // Remember that this is the active value in the block.
474 StoredValue = SI->getOperand(0);
475 } else if (auto *AI = dyn_cast<AllocaInst>(&I)) {
476 // Check if this an alloca, in which case we treat it as a store of
477 // getValueToUseForAlloca.
478 if (!isInstInList(AI, Insts))
479 continue;
480 StoredValue = getValueToUseForAlloca(AI);
481 }
482 }
483
484 // The last stored value that happened is the live-out for the block.
485 assert(StoredValue && "Already checked that there is a store in block");
486 SSA.AddAvailableValue(BB, StoredValue);
487 BlockUses.clear();
488 }
489
490 // Okay, now we rewrite all loads that use live-in values in the loop,
491 // inserting PHI nodes as necessary.
492 for (LoadInst *ALoad : LiveInLoads) {
493 Value *NewVal = SSA.GetValueInMiddleOfBlock(ALoad->getParent());
494 replaceLoadWithValue(ALoad, NewVal);
495
496 // Avoid assertions in unreachable code.
497 if (NewVal == ALoad) NewVal = PoisonValue::get(NewVal->getType());
498 ALoad->replaceAllUsesWith(NewVal);
499 ReplacedLoads[ALoad] = NewVal;
500 }
501
502 // Allow the client to do stuff before we start nuking things.
504
505 // Now that everything is rewritten, delete the old instructions from the
506 // function. They should all be dead now.
507 for (Instruction *User : Insts) {
508 if (!shouldDelete(User))
509 continue;
510
511 // If this is a load that still has uses, then the load must have been added
512 // as a live value in the SSAUpdate data structure for a block (e.g. because
513 // the loaded value was stored later). In this case, we need to recursively
514 // propagate the updates until we get to the real value.
515 if (!User->use_empty()) {
516 Value *NewVal = ReplacedLoads[User];
517 assert(NewVal && "not a replaced load?");
518
519 // Propagate down to the ultimate replacee. The intermediately loads
520 // could theoretically already have been deleted, so we don't want to
521 // dereference the Value*'s.
522 DenseMap<Value*, Value*>::iterator RLI = ReplacedLoads.find(NewVal);
523 while (RLI != ReplacedLoads.end()) {
524 NewVal = RLI->second;
525 RLI = ReplacedLoads.find(NewVal);
526 }
527
528 replaceLoadWithValue(cast<LoadInst>(User), NewVal);
529 User->replaceAllUsesWith(NewVal);
530 }
531
533 User->eraseFromParent();
534 }
535}
536
537bool
540 const {
541 return is_contained(Insts, I);
542}
Rewrite undef for PHI
MachineBasicBlock MachineBasicBlock::iterator DebugLoc DL
This file contains the declarations for the subclasses of Constant, which represent the different fla...
#define LLVM_DEBUG(...)
Definition: Debug.h:106
This file defines the DenseMap class.
std::string Name
This file provides various utilities for inspecting and working with the control flow graph in LLVM I...
This defines the Use class.
#define I(x, y, z)
Definition: MD5.cpp:58
static AvailableValsTy & getAvailableVals(void *AV)
DenseMap< MachineBasicBlock *, Register > AvailableValsTy
Memory SSA
Definition: MemorySSA.cpp:72
#define P(N)
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
static AvailableValsTy & getAvailableVals(void *AV)
Definition: SSAUpdater.cpp:41
static bool IsEquivalentPHI(PHINode *PHI, SmallDenseMap< BasicBlock *, Value *, 8 > &ValueMapping)
Definition: SSAUpdater.cpp:76
This file contains some templates that are useful if you are working with the STL at all.
This file defines the SmallVector class.
Class recording the (high level) value of a variable.
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:41
bool empty() const
empty - Check if the array is empty.
Definition: ArrayRef.h:163
LLVM Basic Block Representation.
Definition: BasicBlock.h:61
iterator begin()
Instruction iterator methods.
Definition: BasicBlock.h:448
iterator_range< const_phi_iterator > phis() const
Returns a range that iterates over the phis in the basic block.
Definition: BasicBlock.h:517
const Instruction * getFirstNonPHI() const
Returns a pointer to the first instruction in this block that is not a PHINode instruction.
Definition: BasicBlock.cpp:367
const DataLayout & getDataLayout() const
Get the data layout of the module this basic block belongs to.
Definition: BasicBlock.cpp:296
const BasicBlock * getParent() const
This represents the llvm.dbg.value instruction.
Record of a variable value-assignment, aka a non instruction representation of the dbg....
void replaceVariableLocationOp(Value *OldValue, Value *NewValue, bool AllowEmpty=false)
A debug info location.
Definition: DebugLoc.h:33
ValueT lookup(const_arg_type_t< KeyT > Val) const
lookup - Return the entry for the specified key, or a default constructed value if no such entry exis...
Definition: DenseMap.h:194
iterator find(const_arg_type_t< KeyT > Val)
Definition: DenseMap.h:156
unsigned size() const
Definition: DenseMap.h:99
size_type count(const_arg_type_t< KeyT > Val) const
Return 1 if the specified key is in the map, 0 otherwise.
Definition: DenseMap.h:152
iterator end()
Definition: DenseMap.h:84
void insertBefore(Instruction *InsertPos)
Insert an unlinked instruction into a basic block immediately before the specified instruction.
Definition: Instruction.cpp:97
InstListType::iterator eraseFromParent()
This method unlinks 'this' from the containing basic block and deletes it.
Definition: Instruction.cpp:92
void setDebugLoc(DebugLoc Loc)
Set the debug location information for this instruction.
Definition: Instruction.h:468
virtual Value * getValueToUseForAlloca(Instruction *AI) const
Return the value to use for the point in the code that the alloca is positioned.
Definition: SSAUpdater.h:195
virtual void instructionDeleted(Instruction *I) const
Called before each instruction is deleted.
Definition: SSAUpdater.h:183
virtual void doExtraRewritesBeforeFinalDeletion()
This hook is invoked after all the stores are found and inserted as available values.
Definition: SSAUpdater.h:176
LoadAndStorePromoter(ArrayRef< const Instruction * > Insts, SSAUpdater &S, StringRef Name=StringRef())
Definition: SSAUpdater.cpp:371
virtual bool isInstInList(Instruction *I, const SmallVectorImpl< Instruction * > &Insts) const
Return true if the specified instruction is in the Inst list.
Definition: SSAUpdater.cpp:538
virtual void replaceLoadWithValue(LoadInst *LI, Value *V) const
Clients can choose to implement this to get notified right before a load is RAUW'd another value.
Definition: SSAUpdater.h:180
void run(const SmallVectorImpl< Instruction * > &Insts)
This does the promotion.
Definition: SSAUpdater.cpp:386
virtual void updateDebugInfo(Instruction *I) const
Called to update debug info associated with the instruction.
Definition: SSAUpdater.h:186
virtual bool shouldDelete(Instruction *I) const
Return false if a sub-class wants to keep one of the loads/stores after the SSA construction.
Definition: SSAUpdater.h:190
An instruction for reading from memory.
Definition: Instructions.h:176
void addIncoming(Value *V, BasicBlock *BB)
Add an incoming value to the end of the PHI list.
static PHINode * Create(Type *Ty, unsigned NumReservedValues, const Twine &NameStr="", InsertPosition InsertBefore=nullptr)
Constructors - NumReservedValues is a hint for the number of incoming edges that this phi node will h...
static PoisonValue * get(Type *T)
Static factory methods - Return an 'poison' object of the specified type.
Definition: Constants.cpp:1878
bool operator!=(const PHI_iterator &x) const
Definition: SSAUpdater.cpp:285
bool operator==(const PHI_iterator &x) const
Definition: SSAUpdater.cpp:284
static BlkSucc_iterator BlkSucc_end(BlkT *BB)
Definition: SSAUpdater.cpp:270
static BlkSucc_iterator BlkSucc_begin(BlkT *BB)
Definition: SSAUpdater.cpp:269
static void FindPredecessorBlocks(BasicBlock *BB, SmallVectorImpl< BasicBlock * > *Preds)
FindPredecessorBlocks - Put the predecessors of Info->BB into the Preds vector, set Info->NumPreds,...
Definition: SSAUpdater.cpp:298
static Value * CreateEmptyPHI(BasicBlock *BB, unsigned NumPreds, SSAUpdater *Updater)
CreateEmptyPHI - Create a new PHI instruction in the specified block.
Definition: SSAUpdater.cpp:317
static PHINode * ValueIsNewPHI(Value *Val, SSAUpdater *Updater)
ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source operands, i....
Definition: SSAUpdater.cpp:338
static PHI_iterator PHI_begin(PhiT *PHI)
Definition: SSAUpdater.cpp:291
static void AddPHIOperand(PHINode *PHI, Value *Val, BasicBlock *Pred)
AddPHIOperand - Add the specified value as an operand of the PHI for the specified predecessor block.
Definition: SSAUpdater.cpp:327
static Value * GetPHIValue(PHINode *PHI)
GetPHIValue - For the specified PHI instruction, return the value that it defines.
Definition: SSAUpdater.cpp:347
static Value * GetPoisonVal(BasicBlock *BB, SSAUpdater *Updater)
GetPoisonVal - Get a poison value of the same type as the value being handled.
Definition: SSAUpdater.cpp:311
static PHI_iterator PHI_end(PhiT *PHI)
Definition: SSAUpdater.cpp:292
static PHINode * ValueIsPHI(Value *Val, SSAUpdater *Updater)
ValueIsPHI - Check if a value is a PHI.
Definition: SSAUpdater.cpp:332
Helper class for SSA formation on a set of values defined in multiple blocks.
Definition: SSAUpdater.h:40
void RewriteUse(Use &U)
Rewrite a use of the symbolic value.
Definition: SSAUpdater.cpp:187
void RewriteUseAfterInsertions(Use &U)
Rewrite a use like RewriteUse but handling in-block definitions.
Definition: SSAUpdater.cpp:247
Value * FindValueForBlock(BasicBlock *BB) const
Return the value for the specified block if the SSAUpdater has one, otherwise return nullptr.
Definition: SSAUpdater.cpp:65
void Initialize(Type *Ty, StringRef Name)
Reset this object to get ready for a new set of SSA updates with type 'Ty'.
Definition: SSAUpdater.cpp:52
Value * GetValueInMiddleOfBlock(BasicBlock *BB)
Construct SSA form, materializing a value that is live in the middle of the specified block.
Definition: SSAUpdater.cpp:97
SSAUpdater(SmallVectorImpl< PHINode * > *InsertedPHIs=nullptr)
If InsertedPHIs is specified, it will be filled in with all PHI Nodes created by rewriting.
Definition: SSAUpdater.cpp:45
void UpdateDebugValues(Instruction *I)
Rewrite debug value intrinsics to conform to a new SSA form.
Definition: SSAUpdater.cpp:199
bool HasValueForBlock(BasicBlock *BB) const
Return true if the SSAUpdater already has a value for the specified block.
Definition: SSAUpdater.cpp:61
Value * GetValueAtEndOfBlock(BasicBlock *BB)
Construct SSA form, materializing a value that is live at the end of the specified block.
Definition: SSAUpdater.cpp:92
void AddAvailableValue(BasicBlock *BB, Value *V)
Indicate that a rewritten value is available in the specified block with the specified value.
Definition: SSAUpdater.cpp:69
bool empty() const
Definition: SmallVector.h:81
size_t size() const
Definition: SmallVector.h:78
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: SmallVector.h:573
void push_back(const T &Elt)
Definition: SmallVector.h:413
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1196
An instruction for storing to memory.
Definition: Instructions.h:292
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:51
constexpr bool empty() const
empty - Check if the string is empty.
Definition: StringRef.h:147
TinyPtrVector - This class is specialized for cases where there are normally 0 or 1 element in a vect...
Definition: TinyPtrVector.h:29
bool empty() const
unsigned size() const
The instances of the Type class are immutable: once they are created, they are never changed.
Definition: Type.h:45
A Use represents the edge between a Value definition and its users.
Definition: Use.h:43
LLVM Value Representation.
Definition: Value.h:74
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:255
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:534
bool use_empty() const
Definition: Value.h:344
StringRef getName() const
Return a constant reference to the value's name.
Definition: Value.cpp:309
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
void append_range(Container &C, Range &&R)
Wrapper function to append range R to container C.
Definition: STLExtras.h:2115
void findDbgValues(SmallVectorImpl< DbgValueInst * > &DbgValues, Value *V, SmallVectorImpl< DbgVariableRecord * > *DbgVariableRecords=nullptr)
Finds the llvm.dbg.value intrinsics describing a value.
Definition: DebugInfo.cpp:155
bool operator==(const AddressRangeValuePair &LHS, const AddressRangeValuePair &RHS)
Value * simplifyInstruction(Instruction *I, const SimplifyQuery &Q)
See if we can compute a simplified version of this instruction.
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:163
SuccIterator< Instruction, BasicBlock > succ_iterator
Definition: CFG.h:242
RNSuccIterator< NodeRef, BlockT, RegionT > succ_begin(NodeRef Node)
RNSuccIterator< NodeRef, BlockT, RegionT > succ_end(NodeRef Node)
auto predecessors(const MachineBasicBlock *BB)
bool is_contained(R &&Range, const E &Element)
Returns true if Element is found in Range.
Definition: STLExtras.h:1903