LLVM  6.0.0svn
SSAUpdater.cpp
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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/STLExtras.h"
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ADT/TinyPtrVector.h"
21 #include "llvm/IR/BasicBlock.h"
22 #include "llvm/IR/CFG.h"
23 #include "llvm/IR/Constants.h"
24 #include "llvm/IR/DebugLoc.h"
25 #include "llvm/IR/Instruction.h"
26 #include "llvm/IR/Instructions.h"
27 #include "llvm/IR/Module.h"
28 #include "llvm/IR/Use.h"
29 #include "llvm/IR/Value.h"
30 #include "llvm/IR/ValueHandle.h"
31 #include "llvm/Support/Casting.h"
32 #include "llvm/Support/Debug.h"
35 #include <cassert>
36 #include <utility>
37 
38 using namespace llvm;
39 
40 #define DEBUG_TYPE "ssaupdater"
41 
43 static AvailableValsTy &getAvailableVals(void *AV) {
44  return *static_cast<AvailableValsTy*>(AV);
45 }
46 
48  : InsertedPHIs(NewPHI) {}
49 
51  delete static_cast<AvailableValsTy*>(AV);
52 }
53 
55  if (!AV)
56  AV = new AvailableValsTy();
57  else
58  getAvailableVals(AV).clear();
59  ProtoType = Ty;
60  ProtoName = Name;
61 }
62 
64  return getAvailableVals(AV).count(BB);
65 }
66 
68  assert(ProtoType && "Need to initialize SSAUpdater");
69  assert(ProtoType == V->getType() &&
70  "All rewritten values must have the same type");
71  getAvailableVals(AV)[BB] = V;
72 }
73 
74 static bool IsEquivalentPHI(PHINode *PHI,
76  unsigned PHINumValues = PHI->getNumIncomingValues();
77  if (PHINumValues != ValueMapping.size())
78  return false;
79 
80  // Scan the phi to see if it matches.
81  for (unsigned i = 0, e = PHINumValues; i != e; ++i)
82  if (ValueMapping[PHI->getIncomingBlock(i)] !=
83  PHI->getIncomingValue(i)) {
84  return false;
85  }
86 
87  return true;
88 }
89 
91  Value *Res = GetValueAtEndOfBlockInternal(BB);
92  return Res;
93 }
94 
96  // If there is no definition of the renamed variable in this block, just use
97  // GetValueAtEndOfBlock to do our work.
98  if (!HasValueForBlock(BB))
99  return GetValueAtEndOfBlock(BB);
100 
101  // Otherwise, we have the hard case. Get the live-in values for each
102  // predecessor.
104  Value *SingularValue = nullptr;
105 
106  // We can get our predecessor info by walking the pred_iterator list, but it
107  // is relatively slow. If we already have PHI nodes in this block, walk one
108  // of them to get the predecessor list instead.
109  if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin())) {
110  for (unsigned i = 0, e = SomePhi->getNumIncomingValues(); i != e; ++i) {
111  BasicBlock *PredBB = SomePhi->getIncomingBlock(i);
112  Value *PredVal = GetValueAtEndOfBlock(PredBB);
113  PredValues.push_back(std::make_pair(PredBB, PredVal));
114 
115  // Compute SingularValue.
116  if (i == 0)
117  SingularValue = PredVal;
118  else if (PredVal != SingularValue)
119  SingularValue = nullptr;
120  }
121  } else {
122  bool isFirstPred = true;
123  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
124  BasicBlock *PredBB = *PI;
125  Value *PredVal = GetValueAtEndOfBlock(PredBB);
126  PredValues.push_back(std::make_pair(PredBB, PredVal));
127 
128  // Compute SingularValue.
129  if (isFirstPred) {
130  SingularValue = PredVal;
131  isFirstPred = false;
132  } else if (PredVal != SingularValue)
133  SingularValue = nullptr;
134  }
135  }
136 
137  // If there are no predecessors, just return undef.
138  if (PredValues.empty())
139  return UndefValue::get(ProtoType);
140 
141  // Otherwise, if all the merged values are the same, just use it.
142  if (SingularValue)
143  return SingularValue;
144 
145  // Otherwise, we do need a PHI: check to see if we already have one available
146  // in this block that produces the right value.
147  if (isa<PHINode>(BB->begin())) {
149  PredValues.end());
150  PHINode *SomePHI;
151  for (BasicBlock::iterator It = BB->begin();
152  (SomePHI = dyn_cast<PHINode>(It)); ++It) {
153  if (IsEquivalentPHI(SomePHI, ValueMapping))
154  return SomePHI;
155  }
156  }
157 
158  // Ok, we have no way out, insert a new one now.
159  PHINode *InsertedPHI = PHINode::Create(ProtoType, PredValues.size(),
160  ProtoName, &BB->front());
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->getModule()->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  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  // Notify that users of the existing value that it is being replaced.
197  Value *OldVal = U.get();
198  if (OldVal != V && OldVal->hasValueHandle())
200 
201  U.set(V);
202 }
203 
205  Instruction *User = cast<Instruction>(U.getUser());
206 
207  Value *V;
208  if (PHINode *UserPN = dyn_cast<PHINode>(User))
209  V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U));
210  else
211  V = GetValueAtEndOfBlock(User->getParent());
212 
213  U.set(V);
214 }
215 
216 namespace llvm {
217 
218 template<>
220 public:
221  typedef BasicBlock BlkT;
222  typedef Value *ValT;
223  typedef PHINode PhiT;
224 
226  static BlkSucc_iterator BlkSucc_begin(BlkT *BB) { return succ_begin(BB); }
227  static BlkSucc_iterator BlkSucc_end(BlkT *BB) { return succ_end(BB); }
228 
229  class PHI_iterator {
230  private:
231  PHINode *PHI;
232  unsigned idx;
233 
234  public:
235  explicit PHI_iterator(PHINode *P) // begin iterator
236  : PHI(P), idx(0) {}
237  PHI_iterator(PHINode *P, bool) // end iterator
238  : PHI(P), idx(PHI->getNumIncomingValues()) {}
239 
240  PHI_iterator &operator++() { ++idx; return *this; }
241  bool operator==(const PHI_iterator& x) const { return idx == x.idx; }
242  bool operator!=(const PHI_iterator& x) const { return !operator==(x); }
243 
244  Value *getIncomingValue() { return PHI->getIncomingValue(idx); }
246  };
247 
248  static PHI_iterator PHI_begin(PhiT *PHI) { return PHI_iterator(PHI); }
249  static PHI_iterator PHI_end(PhiT *PHI) {
250  return PHI_iterator(PHI, true);
251  }
252 
253  /// FindPredecessorBlocks - Put the predecessors of Info->BB into the Preds
254  /// vector, set Info->NumPreds, and allocate space in Info->Preds.
257  // We can get our predecessor info by walking the pred_iterator list,
258  // but it is relatively slow. If we already have PHI nodes in this
259  // block, walk one of them to get the predecessor list instead.
260  if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin())) {
261  Preds->append(SomePhi->block_begin(), SomePhi->block_end());
262  } else {
263  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
264  Preds->push_back(*PI);
265  }
266  }
267 
268  /// GetUndefVal - Get an undefined value of the same type as the value
269  /// being handled.
270  static Value *GetUndefVal(BasicBlock *BB, SSAUpdater *Updater) {
271  return UndefValue::get(Updater->ProtoType);
272  }
273 
274  /// CreateEmptyPHI - Create a new PHI instruction in the specified block.
275  /// Reserve space for the operands but do not fill them in yet.
276  static Value *CreateEmptyPHI(BasicBlock *BB, unsigned NumPreds,
277  SSAUpdater *Updater) {
278  PHINode *PHI = PHINode::Create(Updater->ProtoType, NumPreds,
279  Updater->ProtoName, &BB->front());
280  return PHI;
281  }
282 
283  /// AddPHIOperand - Add the specified value as an operand of the PHI for
284  /// the specified predecessor block.
285  static void AddPHIOperand(PHINode *PHI, Value *Val, BasicBlock *Pred) {
286  PHI->addIncoming(Val, Pred);
287  }
288 
289  /// InstrIsPHI - Check if an instruction is a PHI.
290  ///
292  return dyn_cast<PHINode>(I);
293  }
294 
295  /// ValueIsPHI - Check if a value is a PHI.
296  ///
297  static PHINode *ValueIsPHI(Value *Val, SSAUpdater *Updater) {
298  return dyn_cast<PHINode>(Val);
299  }
300 
301  /// ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source
302  /// operands, i.e., it was just added.
303  static PHINode *ValueIsNewPHI(Value *Val, SSAUpdater *Updater) {
304  PHINode *PHI = ValueIsPHI(Val, Updater);
305  if (PHI && PHI->getNumIncomingValues() == 0)
306  return PHI;
307  return nullptr;
308  }
309 
310  /// GetPHIValue - For the specified PHI instruction, return the value
311  /// that it defines.
312  static Value *GetPHIValue(PHINode *PHI) {
313  return PHI;
314  }
315 };
316 
317 } // end namespace llvm
318 
319 /// Check to see if AvailableVals has an entry for the specified BB and if so,
320 /// return it. If not, construct SSA form by first calculating the required
321 /// placement of PHIs and then inserting new PHIs where needed.
322 Value *SSAUpdater::GetValueAtEndOfBlockInternal(BasicBlock *BB) {
323  AvailableValsTy &AvailableVals = getAvailableVals(AV);
324  if (Value *V = AvailableVals[BB])
325  return V;
326 
327  SSAUpdaterImpl<SSAUpdater> Impl(this, &AvailableVals, InsertedPHIs);
328  return Impl.GetValue(BB);
329 }
330 
331 //===----------------------------------------------------------------------===//
332 // LoadAndStorePromoter Implementation
333 //===----------------------------------------------------------------------===//
334 
337  SSAUpdater &S, StringRef BaseName) : SSA(S) {
338  if (Insts.empty()) return;
339 
340  const Value *SomeVal;
341  if (const LoadInst *LI = dyn_cast<LoadInst>(Insts[0]))
342  SomeVal = LI;
343  else
344  SomeVal = cast<StoreInst>(Insts[0])->getOperand(0);
345 
346  if (BaseName.empty())
347  BaseName = SomeVal->getName();
348  SSA.Initialize(SomeVal->getType(), BaseName);
349 }
350 
352 run(const SmallVectorImpl<Instruction*> &Insts) const {
353  // First step: bucket up uses of the alloca by the block they occur in.
354  // This is important because we have to handle multiple defs/uses in a block
355  // ourselves: SSAUpdater is purely for cross-block references.
357 
358  for (Instruction *User : Insts)
359  UsesByBlock[User->getParent()].push_back(User);
360 
361  // Okay, now we can iterate over all the blocks in the function with uses,
362  // processing them. Keep track of which loads are loading a live-in value.
363  // Walk the uses in the use-list order to be determinstic.
364  SmallVector<LoadInst*, 32> LiveInLoads;
365  DenseMap<Value*, Value*> ReplacedLoads;
366 
367  for (Instruction *User : Insts) {
368  BasicBlock *BB = User->getParent();
369  TinyPtrVector<Instruction*> &BlockUses = UsesByBlock[BB];
370 
371  // If this block has already been processed, ignore this repeat use.
372  if (BlockUses.empty()) continue;
373 
374  // Okay, this is the first use in the block. If this block just has a
375  // single user in it, we can rewrite it trivially.
376  if (BlockUses.size() == 1) {
377  // If it is a store, it is a trivial def of the value in the block.
378  if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
380  SSA.AddAvailableValue(BB, SI->getOperand(0));
381  } else
382  // Otherwise it is a load, queue it to rewrite as a live-in load.
383  LiveInLoads.push_back(cast<LoadInst>(User));
384  BlockUses.clear();
385  continue;
386  }
387 
388  // Otherwise, check to see if this block is all loads.
389  bool HasStore = false;
390  for (Instruction *I : BlockUses) {
391  if (isa<StoreInst>(I)) {
392  HasStore = true;
393  break;
394  }
395  }
396 
397  // If so, we can queue them all as live in loads. We don't have an
398  // efficient way to tell which on is first in the block and don't want to
399  // scan large blocks, so just add all loads as live ins.
400  if (!HasStore) {
401  for (Instruction *I : BlockUses)
402  LiveInLoads.push_back(cast<LoadInst>(I));
403  BlockUses.clear();
404  continue;
405  }
406 
407  // Otherwise, we have mixed loads and stores (or just a bunch of stores).
408  // Since SSAUpdater is purely for cross-block values, we need to determine
409  // the order of these instructions in the block. If the first use in the
410  // block is a load, then it uses the live in value. The last store defines
411  // the live out value. We handle this by doing a linear scan of the block.
412  Value *StoredValue = nullptr;
413  for (Instruction &I : *BB) {
414  if (LoadInst *L = dyn_cast<LoadInst>(&I)) {
415  // If this is a load from an unrelated pointer, ignore it.
416  if (!isInstInList(L, Insts)) continue;
417 
418  // If we haven't seen a store yet, this is a live in use, otherwise
419  // use the stored value.
420  if (StoredValue) {
421  replaceLoadWithValue(L, StoredValue);
422  L->replaceAllUsesWith(StoredValue);
423  ReplacedLoads[L] = StoredValue;
424  } else {
425  LiveInLoads.push_back(L);
426  }
427  continue;
428  }
429 
430  if (StoreInst *SI = dyn_cast<StoreInst>(&I)) {
431  // If this is a store to an unrelated pointer, ignore it.
432  if (!isInstInList(SI, Insts)) continue;
434 
435  // Remember that this is the active value in the block.
436  StoredValue = SI->getOperand(0);
437  }
438  }
439 
440  // The last stored value that happened is the live-out for the block.
441  assert(StoredValue && "Already checked that there is a store in block");
442  SSA.AddAvailableValue(BB, StoredValue);
443  BlockUses.clear();
444  }
445 
446  // Okay, now we rewrite all loads that use live-in values in the loop,
447  // inserting PHI nodes as necessary.
448  for (LoadInst *ALoad : LiveInLoads) {
449  Value *NewVal = SSA.GetValueInMiddleOfBlock(ALoad->getParent());
450  replaceLoadWithValue(ALoad, NewVal);
451 
452  // Avoid assertions in unreachable code.
453  if (NewVal == ALoad) NewVal = UndefValue::get(NewVal->getType());
454  ALoad->replaceAllUsesWith(NewVal);
455  ReplacedLoads[ALoad] = NewVal;
456  }
457 
458  // Allow the client to do stuff before we start nuking things.
460 
461  // Now that everything is rewritten, delete the old instructions from the
462  // function. They should all be dead now.
463  for (Instruction *User : Insts) {
464  // If this is a load that still has uses, then the load must have been added
465  // as a live value in the SSAUpdate data structure for a block (e.g. because
466  // the loaded value was stored later). In this case, we need to recursively
467  // propagate the updates until we get to the real value.
468  if (!User->use_empty()) {
469  Value *NewVal = ReplacedLoads[User];
470  assert(NewVal && "not a replaced load?");
471 
472  // Propagate down to the ultimate replacee. The intermediately loads
473  // could theoretically already have been deleted, so we don't want to
474  // dereference the Value*'s.
475  DenseMap<Value*, Value*>::iterator RLI = ReplacedLoads.find(NewVal);
476  while (RLI != ReplacedLoads.end()) {
477  NewVal = RLI->second;
478  RLI = ReplacedLoads.find(NewVal);
479  }
480 
481  replaceLoadWithValue(cast<LoadInst>(User), NewVal);
482  User->replaceAllUsesWith(NewVal);
483  }
484 
486  User->eraseFromParent();
487  }
488 }
489 
490 bool
492  const SmallVectorImpl<Instruction*> &Insts)
493  const {
494  return is_contained(Insts, I);
495 }
SymbolTableList< Instruction >::iterator eraseFromParent()
This method unlinks &#39;this&#39; from the containing basic block and deletes it.
Definition: Instruction.cpp:69
Helper class for SSA formation on a set of values defined in multiple blocks.
Definition: SSAUpdater.h:39
static BlkSucc_iterator BlkSucc_end(BlkT *BB)
Definition: SSAUpdater.cpp:227
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:285
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
void Initialize(Type *Ty, StringRef Name)
Reset this object to get ready for a new set of SSA updates with type &#39;Ty&#39;.
Definition: SSAUpdater.cpp:54
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:136
static BlkSucc_iterator BlkSucc_begin(BlkT *BB)
Definition: SSAUpdater.cpp:226
virtual void instructionDeleted(Instruction *I) const
Called before each instruction is deleted.
Definition: SSAUpdater.h:168
void AddAvailableValue(BasicBlock *BB, Value *V)
Indicate that a rewritten value is available in the specified block with the specified value...
Definition: SSAUpdater.cpp:67
static Value * CreateEmptyPHI(BasicBlock *BB, unsigned NumPreds, SSAUpdater *Updater)
CreateEmptyPHI - Create a new PHI instruction in the specified block.
Definition: SSAUpdater.cpp:276
A debug info location.
Definition: DebugLoc.h:34
ValT GetValue(BlkT *BB)
GetValue - Check to see if AvailableVals has an entry for the specified BB and if so...
An instruction for reading from memory.
Definition: Instructions.h:164
This defines the Use class.
TinyPtrVector - This class is specialized for cases where there are normally 0 or 1 element in a vect...
Definition: TinyPtrVector.h:31
Value * get() const
Definition: Use.h:108
iterator begin()
Instruction iterator methods.
Definition: BasicBlock.h:252
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
const DataLayout & getDataLayout() const
Get the data layout for the module&#39;s target platform.
Definition: Module.cpp:361
virtual bool isInstInList(Instruction *I, const SmallVectorImpl< Instruction *> &Insts) const
Return true if the specified instruction is in the Inst list.
Definition: SSAUpdater.cpp:491
static PHINode * InstrIsPHI(Instruction *I)
InstrIsPHI - Check if an instruction is a PHI.
Definition: SSAUpdater.cpp:291
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:42
static PHI_iterator PHI_begin(PhiT *PHI)
Definition: SSAUpdater.cpp:248
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
User * getUser() const LLVM_READONLY
Returns the User that contains this Use.
Definition: Use.cpp:41
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:245
virtual void doExtraRewritesBeforeFinalDeletion() const
This hook is invoked after all the stores are found and inserted as available values.
Definition: SSAUpdater.h:159
bool operator==(const PHI_iterator &x) const
Definition: SSAUpdater.cpp:241
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool empty() const
empty - Check if the string is empty.
Definition: StringRef.h:133
Memory SSA
Definition: MemorySSA.cpp:50
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:306
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:428
static void ValueIsRAUWd(Value *Old, Value *New)
Definition: Value.cpp:877
DenseMap< BasicBlock *, Value * > AvailableValsTy
Definition: SSAUpdater.cpp:42
const char * Name
static Value * GetUndefVal(BasicBlock *BB, SSAUpdater *Updater)
GetUndefVal - Get an undefined value of the same type as the value being handled. ...
Definition: SSAUpdater.cpp:270
Interval::succ_iterator succ_end(Interval *I)
Definition: Interval.h:109
virtual void updateDebugInfo(Instruction *I) const
Called to update debug info associated with the instruction.
Definition: SSAUpdater.h:172
#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:95
const Instruction * getFirstNonPHI() const
Returns a pointer to the first instruction in this block that is not a PHINode instruction.
Definition: BasicBlock.cpp:171
void setDebugLoc(DebugLoc Loc)
Set the debug location information for this instruction.
Definition: Instruction.h:277
void set(Value *Val)
Definition: Value.h:671
LLVM Basic Block Representation.
Definition: BasicBlock.h:59
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
void RewriteUseAfterInsertions(Use &U)
Rewrite a use like RewriteUse but handling in-block definitions.
Definition: SSAUpdater.cpp:204
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator begin()
Definition: SmallVector.h:116
This file contains the declarations for the subclasses of Constant, which represent the different fla...
const Instruction & front() const
Definition: BasicBlock.h:264
SSAUpdater(SmallVectorImpl< PHINode *> *InsertedPHIs=nullptr)
If InsertedPHIs is specified, it will be filled in with all PHI Nodes created by rewriting.
Definition: SSAUpdater.cpp:47
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
bool empty() const
Interval::pred_iterator pred_end(Interval *I)
Definition: Interval.h:119
static UndefValue * get(Type *T)
Static factory methods - Return an &#39;undef&#39; object of the specified type.
Definition: Constants.cpp:1320
static AvailableValsTy & getAvailableVals(void *AV)
Definition: SSAUpdater.cpp:43
Value * getIncomingValue(unsigned i) const
Return incoming value number x.
static PHINode * ValueIsPHI(Value *Val, SSAUpdater *Updater)
ValueIsPHI - Check if a value is a PHI.
Definition: SSAUpdater.cpp:297
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:255
Iterator for intrusive lists based on ilist_node.
#define E
Definition: LargeTest.cpp:27
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:864
Module.h This file contains the declarations for the Module class.
void run(const SmallVectorImpl< Instruction *> &Insts) const
This does the promotion.
Definition: SSAUpdater.cpp:352
static bool IsEquivalentPHI(PHINode *PHI, SmallDenseMap< BasicBlock *, Value *, 8 > &ValueMapping)
Definition: SSAUpdater.cpp:74
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...
unsigned getNumIncomingValues() const
Return the number of incoming edges.
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
virtual void replaceLoadWithValue(LoadInst *LI, Value *V) const
Clients can choose to implement this to get notified right before a load is RAUW&#39;d another value...
Definition: SSAUpdater.h:164
void append(in_iter in_start, in_iter in_end)
Add the specified range to the end of the SmallVector.
Definition: SmallVector.h:398
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator end()
Definition: SmallVector.h:120
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:61
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:218
BasicBlock * getIncomingBlock(unsigned i) const
Return incoming basic block number i.
#define I(x, y, z)
Definition: MD5.cpp:58
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:323
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:126
Helper struct that represents how a value is mapped through different register banks.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
LLVM Value Representation.
Definition: Value.h:73
static PHI_iterator PHI_end(PhiT *PHI)
Definition: SSAUpdater.cpp:249
#define DEBUG(X)
Definition: Debug.h:118
bool operator!=(const PHI_iterator &x) const
Definition: SSAUpdater.cpp:242
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
LoadAndStorePromoter(ArrayRef< const Instruction *> Insts, SSAUpdater &S, StringRef Name=StringRef())
Definition: SSAUpdater.cpp:336
bool operator==(uint64_t V1, const APInt &V2)
Definition: APInt.h:1946
Value * GetValueAtEndOfBlock(BasicBlock *BB)
Construct SSA form, materializing a value that is live at the end of the specified block...
Definition: SSAUpdater.cpp:90
void RewriteUse(Use &U)
Rewrite a use of the symbolic value.
Definition: SSAUpdater.cpp:187
static Value * GetPHIValue(PHINode *PHI)
GetPHIValue - For the specified PHI instruction, return the value that it defines.
Definition: SSAUpdater.cpp:312
Value * SimplifyInstruction(Instruction *I, const SimplifyQuery &Q, OptimizationRemarkEmitter *ORE=nullptr)
See if we can compute a simplified version of this instruction.
static PHINode * ValueIsNewPHI(Value *Val, SSAUpdater *Updater)
ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source operands, i...
Definition: SSAUpdater.cpp:303
bool use_empty() const
Definition: Value.h:322
unsigned size() const
bool empty() const
empty - Check if the array is empty.
Definition: ArrayRef.h:144
const BasicBlock * getParent() const
Definition: Instruction.h:66
bool HasValueForBlock(BasicBlock *BB) const
Return true if the SSAUpdater already has a value for the specified block.
Definition: SSAUpdater.cpp:63
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:872