LLVM  4.0.0
SSAUpdater.cpp
Go to the documentation of this file.
1 //===- SSAUpdater.cpp - Unstructured SSA Update Tool ----------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the SSAUpdater class.
11 //
12 //===----------------------------------------------------------------------===//
13 
15 #include "llvm/ADT/DenseMap.h"
16 #include "llvm/ADT/TinyPtrVector.h"
18 #include "llvm/IR/CFG.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/Instructions.h"
21 #include "llvm/IR/IntrinsicInst.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/Support/Debug.h"
28 
29 using namespace llvm;
30 
31 #define DEBUG_TYPE "ssaupdater"
32 
34 static AvailableValsTy &getAvailableVals(void *AV) {
35  return *static_cast<AvailableValsTy*>(AV);
36 }
37 
39  : AV(nullptr), ProtoType(nullptr), ProtoName(), InsertedPHIs(NewPHI) {}
40 
42  delete static_cast<AvailableValsTy*>(AV);
43 }
44 
46  if (!AV)
47  AV = new AvailableValsTy();
48  else
49  getAvailableVals(AV).clear();
50  ProtoType = Ty;
51  ProtoName = Name;
52 }
53 
55  return getAvailableVals(AV).count(BB);
56 }
57 
59  assert(ProtoType && "Need to initialize SSAUpdater");
60  assert(ProtoType == V->getType() &&
61  "All rewritten values must have the same type");
62  getAvailableVals(AV)[BB] = V;
63 }
64 
65 static bool IsEquivalentPHI(PHINode *PHI,
67  unsigned PHINumValues = PHI->getNumIncomingValues();
68  if (PHINumValues != ValueMapping.size())
69  return false;
70 
71  // Scan the phi to see if it matches.
72  for (unsigned i = 0, e = PHINumValues; i != e; ++i)
73  if (ValueMapping[PHI->getIncomingBlock(i)] !=
74  PHI->getIncomingValue(i)) {
75  return false;
76  }
77 
78  return true;
79 }
80 
82  Value *Res = GetValueAtEndOfBlockInternal(BB);
83  return Res;
84 }
85 
87  // If there is no definition of the renamed variable in this block, just use
88  // GetValueAtEndOfBlock to do our work.
89  if (!HasValueForBlock(BB))
90  return GetValueAtEndOfBlock(BB);
91 
92  // Otherwise, we have the hard case. Get the live-in values for each
93  // predecessor.
95  Value *SingularValue = nullptr;
96 
97  // We can get our predecessor info by walking the pred_iterator list, but it
98  // is relatively slow. If we already have PHI nodes in this block, walk one
99  // of them to get the predecessor list instead.
100  if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin())) {
101  for (unsigned i = 0, e = SomePhi->getNumIncomingValues(); i != e; ++i) {
102  BasicBlock *PredBB = SomePhi->getIncomingBlock(i);
103  Value *PredVal = GetValueAtEndOfBlock(PredBB);
104  PredValues.push_back(std::make_pair(PredBB, PredVal));
105 
106  // Compute SingularValue.
107  if (i == 0)
108  SingularValue = PredVal;
109  else if (PredVal != SingularValue)
110  SingularValue = nullptr;
111  }
112  } else {
113  bool isFirstPred = true;
114  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
115  BasicBlock *PredBB = *PI;
116  Value *PredVal = GetValueAtEndOfBlock(PredBB);
117  PredValues.push_back(std::make_pair(PredBB, PredVal));
118 
119  // Compute SingularValue.
120  if (isFirstPred) {
121  SingularValue = PredVal;
122  isFirstPred = false;
123  } else if (PredVal != SingularValue)
124  SingularValue = nullptr;
125  }
126  }
127 
128  // If there are no predecessors, just return undef.
129  if (PredValues.empty())
130  return UndefValue::get(ProtoType);
131 
132  // Otherwise, if all the merged values are the same, just use it.
133  if (SingularValue)
134  return SingularValue;
135 
136  // Otherwise, we do need a PHI: check to see if we already have one available
137  // in this block that produces the right value.
138  if (isa<PHINode>(BB->begin())) {
140  PredValues.end());
141  PHINode *SomePHI;
142  for (BasicBlock::iterator It = BB->begin();
143  (SomePHI = dyn_cast<PHINode>(It)); ++It) {
144  if (IsEquivalentPHI(SomePHI, ValueMapping))
145  return SomePHI;
146  }
147  }
148 
149  // Ok, we have no way out, insert a new one now.
150  PHINode *InsertedPHI = PHINode::Create(ProtoType, PredValues.size(),
151  ProtoName, &BB->front());
152 
153  // Fill in all the predecessors of the PHI.
154  for (const auto &PredValue : PredValues)
155  InsertedPHI->addIncoming(PredValue.second, PredValue.first);
156 
157  // See if the PHI node can be merged to a single value. This can happen in
158  // loop cases when we get a PHI of itself and one other value.
159  if (Value *V =
160  SimplifyInstruction(InsertedPHI, BB->getModule()->getDataLayout())) {
161  InsertedPHI->eraseFromParent();
162  return V;
163  }
164 
165  // Set the DebugLoc of the inserted PHI, if available.
166  DebugLoc DL;
167  if (const Instruction *I = BB->getFirstNonPHI())
168  DL = I->getDebugLoc();
169  InsertedPHI->setDebugLoc(DL);
170 
171  // If the client wants to know about all new instructions, tell it.
172  if (InsertedPHIs) InsertedPHIs->push_back(InsertedPHI);
173 
174  DEBUG(dbgs() << " Inserted PHI: " << *InsertedPHI << "\n");
175  return InsertedPHI;
176 }
177 
179  Instruction *User = cast<Instruction>(U.getUser());
180 
181  Value *V;
182  if (PHINode *UserPN = dyn_cast<PHINode>(User))
183  V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U));
184  else
185  V = GetValueInMiddleOfBlock(User->getParent());
186 
187  // Notify that users of the existing value that it is being replaced.
188  Value *OldVal = U.get();
189  if (OldVal != V && OldVal->hasValueHandle())
191 
192  U.set(V);
193 }
194 
196  Instruction *User = cast<Instruction>(U.getUser());
197 
198  Value *V;
199  if (PHINode *UserPN = dyn_cast<PHINode>(User))
200  V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U));
201  else
202  V = GetValueAtEndOfBlock(User->getParent());
203 
204  U.set(V);
205 }
206 
207 namespace llvm {
208 template<>
210 public:
211  typedef BasicBlock BlkT;
212  typedef Value *ValT;
213  typedef PHINode PhiT;
214 
216  static BlkSucc_iterator BlkSucc_begin(BlkT *BB) { return succ_begin(BB); }
217  static BlkSucc_iterator BlkSucc_end(BlkT *BB) { return succ_end(BB); }
218 
219  class PHI_iterator {
220  private:
221  PHINode *PHI;
222  unsigned idx;
223 
224  public:
225  explicit PHI_iterator(PHINode *P) // begin iterator
226  : PHI(P), idx(0) {}
227  PHI_iterator(PHINode *P, bool) // end iterator
228  : PHI(P), idx(PHI->getNumIncomingValues()) {}
229 
230  PHI_iterator &operator++() { ++idx; return *this; }
231  bool operator==(const PHI_iterator& x) const { return idx == x.idx; }
232  bool operator!=(const PHI_iterator& x) const { return !operator==(x); }
233  Value *getIncomingValue() { return PHI->getIncomingValue(idx); }
234  BasicBlock *getIncomingBlock() { return PHI->getIncomingBlock(idx); }
235  };
236 
237  static PHI_iterator PHI_begin(PhiT *PHI) { return PHI_iterator(PHI); }
238  static PHI_iterator PHI_end(PhiT *PHI) {
239  return PHI_iterator(PHI, true);
240  }
241 
242  /// FindPredecessorBlocks - Put the predecessors of Info->BB into the Preds
243  /// vector, set Info->NumPreds, and allocate space in Info->Preds.
246  // We can get our predecessor info by walking the pred_iterator list,
247  // but it is relatively slow. If we already have PHI nodes in this
248  // block, walk one of them to get the predecessor list instead.
249  if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin())) {
250  Preds->append(SomePhi->block_begin(), SomePhi->block_end());
251  } else {
252  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
253  Preds->push_back(*PI);
254  }
255  }
256 
257  /// GetUndefVal - Get an undefined value of the same type as the value
258  /// being handled.
259  static Value *GetUndefVal(BasicBlock *BB, SSAUpdater *Updater) {
260  return UndefValue::get(Updater->ProtoType);
261  }
262 
263  /// CreateEmptyPHI - Create a new PHI instruction in the specified block.
264  /// Reserve space for the operands but do not fill them in yet.
265  static Value *CreateEmptyPHI(BasicBlock *BB, unsigned NumPreds,
266  SSAUpdater *Updater) {
267  PHINode *PHI = PHINode::Create(Updater->ProtoType, NumPreds,
268  Updater->ProtoName, &BB->front());
269  return PHI;
270  }
271 
272  /// AddPHIOperand - Add the specified value as an operand of the PHI for
273  /// the specified predecessor block.
274  static void AddPHIOperand(PHINode *PHI, Value *Val, BasicBlock *Pred) {
275  PHI->addIncoming(Val, Pred);
276  }
277 
278  /// InstrIsPHI - Check if an instruction is a PHI.
279  ///
281  return dyn_cast<PHINode>(I);
282  }
283 
284  /// ValueIsPHI - Check if a value is a PHI.
285  ///
286  static PHINode *ValueIsPHI(Value *Val, SSAUpdater *Updater) {
287  return dyn_cast<PHINode>(Val);
288  }
289 
290  /// ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source
291  /// operands, i.e., it was just added.
292  static PHINode *ValueIsNewPHI(Value *Val, SSAUpdater *Updater) {
293  PHINode *PHI = ValueIsPHI(Val, Updater);
294  if (PHI && PHI->getNumIncomingValues() == 0)
295  return PHI;
296  return nullptr;
297  }
298 
299  /// GetPHIValue - For the specified PHI instruction, return the value
300  /// that it defines.
301  static Value *GetPHIValue(PHINode *PHI) {
302  return PHI;
303  }
304 };
305 
306 } // End llvm namespace
307 
308 /// Check to see if AvailableVals has an entry for the specified BB and if so,
309 /// return it. If not, construct SSA form by first calculating the required
310 /// placement of PHIs and then inserting new PHIs where needed.
311 Value *SSAUpdater::GetValueAtEndOfBlockInternal(BasicBlock *BB) {
312  AvailableValsTy &AvailableVals = getAvailableVals(AV);
313  if (Value *V = AvailableVals[BB])
314  return V;
315 
316  SSAUpdaterImpl<SSAUpdater> Impl(this, &AvailableVals, InsertedPHIs);
317  return Impl.GetValue(BB);
318 }
319 
320 //===----------------------------------------------------------------------===//
321 // LoadAndStorePromoter Implementation
322 //===----------------------------------------------------------------------===//
323 
326  SSAUpdater &S, StringRef BaseName) : SSA(S) {
327  if (Insts.empty()) return;
328 
329  const Value *SomeVal;
330  if (const LoadInst *LI = dyn_cast<LoadInst>(Insts[0]))
331  SomeVal = LI;
332  else
333  SomeVal = cast<StoreInst>(Insts[0])->getOperand(0);
334 
335  if (BaseName.empty())
336  BaseName = SomeVal->getName();
337  SSA.Initialize(SomeVal->getType(), BaseName);
338 }
339 
340 
342 run(const SmallVectorImpl<Instruction*> &Insts) const {
343 
344  // First step: bucket up uses of the alloca by the block they occur in.
345  // This is important because we have to handle multiple defs/uses in a block
346  // ourselves: SSAUpdater is purely for cross-block references.
348 
349  for (Instruction *User : Insts)
350  UsesByBlock[User->getParent()].push_back(User);
351 
352  // Okay, now we can iterate over all the blocks in the function with uses,
353  // processing them. Keep track of which loads are loading a live-in value.
354  // Walk the uses in the use-list order to be determinstic.
355  SmallVector<LoadInst*, 32> LiveInLoads;
356  DenseMap<Value*, Value*> ReplacedLoads;
357 
358  for (Instruction *User : Insts) {
359  BasicBlock *BB = User->getParent();
360  TinyPtrVector<Instruction*> &BlockUses = UsesByBlock[BB];
361 
362  // If this block has already been processed, ignore this repeat use.
363  if (BlockUses.empty()) continue;
364 
365  // Okay, this is the first use in the block. If this block just has a
366  // single user in it, we can rewrite it trivially.
367  if (BlockUses.size() == 1) {
368  // If it is a store, it is a trivial def of the value in the block.
369  if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
371  SSA.AddAvailableValue(BB, SI->getOperand(0));
372  } else
373  // Otherwise it is a load, queue it to rewrite as a live-in load.
374  LiveInLoads.push_back(cast<LoadInst>(User));
375  BlockUses.clear();
376  continue;
377  }
378 
379  // Otherwise, check to see if this block is all loads.
380  bool HasStore = false;
381  for (Instruction *I : BlockUses) {
382  if (isa<StoreInst>(I)) {
383  HasStore = true;
384  break;
385  }
386  }
387 
388  // If so, we can queue them all as live in loads. We don't have an
389  // efficient way to tell which on is first in the block and don't want to
390  // scan large blocks, so just add all loads as live ins.
391  if (!HasStore) {
392  for (Instruction *I : BlockUses)
393  LiveInLoads.push_back(cast<LoadInst>(I));
394  BlockUses.clear();
395  continue;
396  }
397 
398  // Otherwise, we have mixed loads and stores (or just a bunch of stores).
399  // Since SSAUpdater is purely for cross-block values, we need to determine
400  // the order of these instructions in the block. If the first use in the
401  // block is a load, then it uses the live in value. The last store defines
402  // the live out value. We handle this by doing a linear scan of the block.
403  Value *StoredValue = nullptr;
404  for (Instruction &I : *BB) {
405  if (LoadInst *L = dyn_cast<LoadInst>(&I)) {
406  // If this is a load from an unrelated pointer, ignore it.
407  if (!isInstInList(L, Insts)) continue;
408 
409  // If we haven't seen a store yet, this is a live in use, otherwise
410  // use the stored value.
411  if (StoredValue) {
412  replaceLoadWithValue(L, StoredValue);
413  L->replaceAllUsesWith(StoredValue);
414  ReplacedLoads[L] = StoredValue;
415  } else {
416  LiveInLoads.push_back(L);
417  }
418  continue;
419  }
420 
421  if (StoreInst *SI = dyn_cast<StoreInst>(&I)) {
422  // If this is a store to an unrelated pointer, ignore it.
423  if (!isInstInList(SI, Insts)) continue;
425 
426  // Remember that this is the active value in the block.
427  StoredValue = SI->getOperand(0);
428  }
429  }
430 
431  // The last stored value that happened is the live-out for the block.
432  assert(StoredValue && "Already checked that there is a store in block");
433  SSA.AddAvailableValue(BB, StoredValue);
434  BlockUses.clear();
435  }
436 
437  // Okay, now we rewrite all loads that use live-in values in the loop,
438  // inserting PHI nodes as necessary.
439  for (LoadInst *ALoad : LiveInLoads) {
440  Value *NewVal = SSA.GetValueInMiddleOfBlock(ALoad->getParent());
441  replaceLoadWithValue(ALoad, NewVal);
442 
443  // Avoid assertions in unreachable code.
444  if (NewVal == ALoad) NewVal = UndefValue::get(NewVal->getType());
445  ALoad->replaceAllUsesWith(NewVal);
446  ReplacedLoads[ALoad] = NewVal;
447  }
448 
449  // Allow the client to do stuff before we start nuking things.
451 
452  // Now that everything is rewritten, delete the old instructions from the
453  // function. They should all be dead now.
454  for (Instruction *User : Insts) {
455  // If this is a load that still has uses, then the load must have been added
456  // as a live value in the SSAUpdate data structure for a block (e.g. because
457  // the loaded value was stored later). In this case, we need to recursively
458  // propagate the updates until we get to the real value.
459  if (!User->use_empty()) {
460  Value *NewVal = ReplacedLoads[User];
461  assert(NewVal && "not a replaced load?");
462 
463  // Propagate down to the ultimate replacee. The intermediately loads
464  // could theoretically already have been deleted, so we don't want to
465  // dereference the Value*'s.
466  DenseMap<Value*, Value*>::iterator RLI = ReplacedLoads.find(NewVal);
467  while (RLI != ReplacedLoads.end()) {
468  NewVal = RLI->second;
469  RLI = ReplacedLoads.find(NewVal);
470  }
471 
472  replaceLoadWithValue(cast<LoadInst>(User), NewVal);
473  User->replaceAllUsesWith(NewVal);
474  }
475 
477  User->eraseFromParent();
478  }
479 }
480 
481 bool
483  const SmallVectorImpl<Instruction*> &Insts)
484  const {
485  return is_contained(Insts, I);
486 }
MachineLoop * L
SymbolTableList< Instruction >::iterator eraseFromParent()
This method unlinks 'this' from the containing basic block and deletes it.
Definition: Instruction.cpp:76
Helper class for SSA formation on a set of values defined in multiple blocks.
Definition: SSAUpdater.h:38
static BlkSucc_iterator BlkSucc_end(BlkT *BB)
Definition: SSAUpdater.cpp:217
void addIncoming(Value *V, BasicBlock *BB)
Add an incoming value to the end of the PHI list.
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:274
void run(const SmallVectorImpl< Instruction * > &Insts) const
This does the promotion.
Definition: SSAUpdater.cpp:342
size_t i
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:45
static BlkSucc_iterator BlkSucc_begin(BlkT *BB)
Definition: SSAUpdater.cpp:216
void AddAvailableValue(BasicBlock *BB, Value *V)
Indicate that a rewritten value is available in the specified block with the specified value...
Definition: SSAUpdater.cpp:58
static Value * CreateEmptyPHI(BasicBlock *BB, unsigned NumPreds, SSAUpdater *Updater)
CreateEmptyPHI - Create a new PHI instruction in the specified block.
Definition: SSAUpdater.cpp:265
virtual void updateDebugInfo(Instruction *I) const
Called to update debug info associated with the instruction.
Definition: SSAUpdater.h:172
A debug info location.
Definition: DebugLoc.h:34
const Instruction & front() const
Definition: BasicBlock.h:240
An instruction for reading from memory.
Definition: Instructions.h:164
TinyPtrVector - This class is specialized for cases where there are normally 0 or 1 element in a vect...
Definition: TinyPtrVector.h:31
StringRef getName() const
Return a constant reference to the value's name.
Definition: Value.cpp:191
iterator begin()
Instruction iterator methods.
Definition: BasicBlock.h:228
const Module * getModule() const
Return the module owning the function this basic block belongs to, or nullptr it the function does no...
Definition: BasicBlock.cpp:116
static PHINode * InstrIsPHI(Instruction *I)
InstrIsPHI - Check if an instruction is a PHI.
Definition: SSAUpdater.cpp:280
A Use represents the edge between a Value definition and its users.
Definition: Use.h:56
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:32
Instruction * getFirstNonPHI()
Returns a pointer to the first instruction in this block that is not a PHINode instruction.
Definition: BasicBlock.cpp:180
virtual void doExtraRewritesBeforeFinalDeletion() const
This hook is invoked after all the stores are found and inserted as available values.
Definition: SSAUpdater.h:159
SSAUpdater(SmallVectorImpl< PHINode * > *InsertedPHIs=nullptr)
If InsertedPHIs is specified, it will be filled in with all PHI Nodes created by rewriting.
Definition: SSAUpdater.cpp:38
static PHI_iterator PHI_begin(PhiT *PHI)
Definition: SSAUpdater.cpp:237
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:60
Interval::succ_iterator succ_begin(Interval *I)
succ_begin/succ_end - define methods so that Intervals may be used just like BasicBlocks can with the...
Definition: Interval.h:106
bool operator==(const PHI_iterator &x) const
Definition: SSAUpdater.cpp:231
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:164
Memory SSA
Definition: MemorySSA.cpp:55
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:33
An instruction for storing to memory.
Definition: Instructions.h:300
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:401
static void ValueIsRAUWd(Value *Old, Value *New)
Definition: Value.cpp:837
virtual void instructionDeleted(Instruction *I) const
Called before each instruction is deleted.
Definition: SSAUpdater.h:168
DenseMap< BasicBlock *, Value * > AvailableValsTy
Definition: SSAUpdater.cpp:33
static Value * GetUndefVal(BasicBlock *BB, SSAUpdater *Updater)
GetUndefVal - Get an undefined value of the same type as the value being handled. ...
Definition: SSAUpdater.cpp:259
static GCRegistry::Add< CoreCLRGC > E("coreclr","CoreCLR-compatible GC")
Interval::succ_iterator succ_end(Interval *I)
Definition: Interval.h:109
unsigned getNumIncomingValues() const
Return the number of incoming edges.
#define P(N)
Value * GetValueInMiddleOfBlock(BasicBlock *BB)
Construct SSA form, materializing a value that is live in the middle of the specified block...
Definition: SSAUpdater.cpp:86
void setDebugLoc(DebugLoc Loc)
Set the debug location information for this instruction.
Definition: Instruction.h:256
void set(Value *Val)
Definition: Value.h:624
LLVM Basic Block Representation.
Definition: BasicBlock.h:51
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:45
void RewriteUseAfterInsertions(Use &U)
Rewrite a use like RewriteUse but handling in-block definitions.
Definition: SSAUpdater.cpp:195
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator begin()
Definition: SmallVector.h:115
This file contains the declarations for the subclasses of Constant, which represent the different fla...
Interval::pred_iterator pred_begin(Interval *I)
pred_begin/pred_end - define methods so that Intervals may be used just like BasicBlocks can with the...
Definition: Interval.h:116
unsigned size() const
BasicBlock * getIncomingBlock(unsigned i) const
Return incoming basic block number i.
Value * get() const
Definition: Use.h:82
User * getUser() const
Returns the User that contains this Use.
Definition: Use.cpp:41
Interval::pred_iterator pred_end(Interval *I)
Definition: Interval.h:119
bool HasValueForBlock(BasicBlock *BB) const
Return true if the SSAUpdater already has a value for the specified block.
Definition: SSAUpdater.cpp:54
bool empty() const
empty - Check if the array is empty.
Definition: ArrayRef.h:136
void append(in_iter in_start, in_iter in_end)
Add the specified range to the end of the SmallVector.
Definition: SmallVector.h:392
static UndefValue * get(Type *T)
Static factory methods - Return an 'undef' object of the specified type.
Definition: Constants.cpp:1337
static AvailableValsTy & getAvailableVals(void *AV)
Definition: SSAUpdater.cpp:34
static PHINode * ValueIsPHI(Value *Val, SSAUpdater *Updater)
ValueIsPHI - Check if a value is a PHI.
Definition: SSAUpdater.cpp:286
Iterator for intrusive lists based on ilist_node.
Value * getIncomingValue(unsigned i) const
Return incoming value number x.
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:843
Module.h This file contains the declarations for the Module class.
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:230
bool empty() const
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:244
static bool IsEquivalentPHI(PHINode *PHI, SmallDenseMap< BasicBlock *, Value *, 8 > &ValueMapping)
Definition: SSAUpdater.cpp:65
static PHINode * Create(Type *Ty, unsigned NumReservedValues, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
Constructors - NumReservedValues is a hint for the number of incoming edges that this phi node will h...
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
size_type count(const KeyT &Val) const
Return 1 if the specified key is in the map, 0 otherwise.
Definition: DenseMap.h:122
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool empty() const
empty - Check if the string is empty.
Definition: StringRef.h:130
const DataLayout & getDataLayout() const
Get the data layout for the module's target platform.
Definition: Module.cpp:384
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator end()
Definition: SmallVector.h:119
virtual bool isInstInList(Instruction *I, const SmallVectorImpl< Instruction * > &Insts) const
Return true if the specified instruction is in the Inst list.
Definition: SSAUpdater.cpp:482
#define I(x, y, z)
Definition: MD5.cpp:54
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:135
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:287
Helper struct that represents how a value is mapped through different register banks.
bool use_empty() const
Definition: Value.h:299
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
LLVM Value Representation.
Definition: Value.h:71
static PHI_iterator PHI_end(PhiT *PHI)
Definition: SSAUpdater.cpp:238
#define DEBUG(X)
Definition: Debug.h:100
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:47
Value * SimplifyInstruction(Instruction *I, const DataLayout &DL, const TargetLibraryInfo *TLI=nullptr, const DominatorTree *DT=nullptr, AssumptionCache *AC=nullptr)
See if we can compute a simplified version of this instruction.
LoadAndStorePromoter(ArrayRef< const Instruction * > Insts, SSAUpdater &S, StringRef Name=StringRef())
Definition: SSAUpdater.cpp:325
bool operator==(uint64_t V1, const APInt &V2)
Definition: APInt.h:1722
Value * GetValueAtEndOfBlock(BasicBlock *BB)
Construct SSA form, materializing a value that is live at the end of the specified block...
Definition: SSAUpdater.cpp:81
bool operator!=(const PHI_iterator &x) const
Definition: SSAUpdater.cpp:232
void RewriteUse(Use &U)
Rewrite a use of the symbolic value.
Definition: SSAUpdater.cpp:178
static Value * GetPHIValue(PHINode *PHI)
GetPHIValue - For the specified PHI instruction, return the value that it defines.
Definition: SSAUpdater.cpp:301
static PHINode * ValueIsNewPHI(Value *Val, SSAUpdater *Updater)
ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source operands, i...
Definition: SSAUpdater.cpp:292
const BasicBlock * getParent() const
Definition: Instruction.h:62
bool is_contained(R &&Range, const E &Element)
Wrapper function around std::find to detect if an element exists in a container.
Definition: STLExtras.h:783