LLVM  8.0.0svn
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/TinyPtrVector.h"
20 #include "llvm/IR/BasicBlock.h"
21 #include "llvm/IR/CFG.h"
22 #include "llvm/IR/Constants.h"
23 #include "llvm/IR/DebugLoc.h"
24 #include "llvm/IR/Instruction.h"
25 #include "llvm/IR/Instructions.h"
26 #include "llvm/IR/Module.h"
27 #include "llvm/IR/Use.h"
28 #include "llvm/IR/Value.h"
29 #include "llvm/IR/ValueHandle.h"
30 #include "llvm/Support/Casting.h"
31 #include "llvm/Support/Debug.h"
34 #include <cassert>
35 #include <utility>
36 
37 using namespace llvm;
38 
39 #define DEBUG_TYPE "ssaupdater"
40 
42 
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  for (PHINode &SomePHI : BB->phis()) {
151  if (IsEquivalentPHI(&SomePHI, ValueMapping))
152  return &SomePHI;
153  }
154  }
155 
156  // Ok, we have no way out, insert a new one now.
157  PHINode *InsertedPHI = PHINode::Create(ProtoType, PredValues.size(),
158  ProtoName, &BB->front());
159 
160  // Fill in all the predecessors of the PHI.
161  for (const auto &PredValue : PredValues)
162  InsertedPHI->addIncoming(PredValue.second, PredValue.first);
163 
164  // See if the PHI node can be merged to a single value. This can happen in
165  // loop cases when we get a PHI of itself and one other value.
166  if (Value *V =
167  SimplifyInstruction(InsertedPHI, BB->getModule()->getDataLayout())) {
168  InsertedPHI->eraseFromParent();
169  return V;
170  }
171 
172  // Set the DebugLoc of the inserted PHI, if available.
173  DebugLoc DL;
174  if (const Instruction *I = BB->getFirstNonPHI())
175  DL = I->getDebugLoc();
176  InsertedPHI->setDebugLoc(DL);
177 
178  // If the client wants to know about all new instructions, tell it.
179  if (InsertedPHIs) InsertedPHIs->push_back(InsertedPHI);
180 
181  LLVM_DEBUG(dbgs() << " Inserted PHI: " << *InsertedPHI << "\n");
182  return InsertedPHI;
183 }
184 
186  Instruction *User = cast<Instruction>(U.getUser());
187 
188  Value *V;
189  if (PHINode *UserPN = dyn_cast<PHINode>(User))
190  V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U));
191  else
192  V = GetValueInMiddleOfBlock(User->getParent());
193 
194  // Notify that users of the existing value that it is being replaced.
195  Value *OldVal = U.get();
196  if (OldVal != V && OldVal->hasValueHandle())
198 
199  U.set(V);
200 }
201 
203  Instruction *User = cast<Instruction>(U.getUser());
204 
205  Value *V;
206  if (PHINode *UserPN = dyn_cast<PHINode>(User))
207  V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U));
208  else
209  V = GetValueAtEndOfBlock(User->getParent());
210 
211  U.set(V);
212 }
213 
214 namespace llvm {
215 
216 template<>
218 public:
219  using BlkT = BasicBlock;
220  using ValT = Value *;
221  using PhiT = PHINode;
223 
224  static BlkSucc_iterator BlkSucc_begin(BlkT *BB) { return succ_begin(BB); }
225  static BlkSucc_iterator BlkSucc_end(BlkT *BB) { return succ_end(BB); }
226 
227  class PHI_iterator {
228  private:
229  PHINode *PHI;
230  unsigned idx;
231 
232  public:
233  explicit PHI_iterator(PHINode *P) // begin iterator
234  : PHI(P), idx(0) {}
235  PHI_iterator(PHINode *P, bool) // end iterator
236  : PHI(P), idx(PHI->getNumIncomingValues()) {}
237 
238  PHI_iterator &operator++() { ++idx; return *this; }
239  bool operator==(const PHI_iterator& x) const { return idx == x.idx; }
240  bool operator!=(const PHI_iterator& x) const { return !operator==(x); }
241 
242  Value *getIncomingValue() { return PHI->getIncomingValue(idx); }
244  };
245 
246  static PHI_iterator PHI_begin(PhiT *PHI) { return PHI_iterator(PHI); }
247  static PHI_iterator PHI_end(PhiT *PHI) {
248  return PHI_iterator(PHI, true);
249  }
250 
251  /// FindPredecessorBlocks - Put the predecessors of Info->BB into the Preds
252  /// vector, set Info->NumPreds, and allocate space in Info->Preds.
255  // We can get our predecessor info by walking the pred_iterator list,
256  // but it is relatively slow. If we already have PHI nodes in this
257  // block, walk one of them to get the predecessor list instead.
258  if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin())) {
259  Preds->append(SomePhi->block_begin(), SomePhi->block_end());
260  } else {
261  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
262  Preds->push_back(*PI);
263  }
264  }
265 
266  /// GetUndefVal - Get an undefined value of the same type as the value
267  /// being handled.
268  static Value *GetUndefVal(BasicBlock *BB, SSAUpdater *Updater) {
269  return UndefValue::get(Updater->ProtoType);
270  }
271 
272  /// CreateEmptyPHI - Create a new PHI instruction in the specified block.
273  /// Reserve space for the operands but do not fill them in yet.
274  static Value *CreateEmptyPHI(BasicBlock *BB, unsigned NumPreds,
275  SSAUpdater *Updater) {
276  PHINode *PHI = PHINode::Create(Updater->ProtoType, NumPreds,
277  Updater->ProtoName, &BB->front());
278  return PHI;
279  }
280 
281  /// AddPHIOperand - Add the specified value as an operand of the PHI for
282  /// the specified predecessor block.
283  static void AddPHIOperand(PHINode *PHI, Value *Val, BasicBlock *Pred) {
284  PHI->addIncoming(Val, Pred);
285  }
286 
287  /// InstrIsPHI - Check if an instruction is a PHI.
288  ///
290  return dyn_cast<PHINode>(I);
291  }
292 
293  /// ValueIsPHI - Check if a value is a PHI.
294  static PHINode *ValueIsPHI(Value *Val, SSAUpdater *Updater) {
295  return dyn_cast<PHINode>(Val);
296  }
297 
298  /// ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source
299  /// operands, i.e., it was just added.
300  static PHINode *ValueIsNewPHI(Value *Val, SSAUpdater *Updater) {
301  PHINode *PHI = ValueIsPHI(Val, Updater);
302  if (PHI && PHI->getNumIncomingValues() == 0)
303  return PHI;
304  return nullptr;
305  }
306 
307  /// GetPHIValue - For the specified PHI instruction, return the value
308  /// that it defines.
309  static Value *GetPHIValue(PHINode *PHI) {
310  return PHI;
311  }
312 };
313 
314 } // end namespace llvm
315 
316 /// Check to see if AvailableVals has an entry for the specified BB and if so,
317 /// return it. If not, construct SSA form by first calculating the required
318 /// placement of PHIs and then inserting new PHIs where needed.
319 Value *SSAUpdater::GetValueAtEndOfBlockInternal(BasicBlock *BB) {
320  AvailableValsTy &AvailableVals = getAvailableVals(AV);
321  if (Value *V = AvailableVals[BB])
322  return V;
323 
324  SSAUpdaterImpl<SSAUpdater> Impl(this, &AvailableVals, InsertedPHIs);
325  return Impl.GetValue(BB);
326 }
327 
328 //===----------------------------------------------------------------------===//
329 // LoadAndStorePromoter Implementation
330 //===----------------------------------------------------------------------===//
331 
334  SSAUpdater &S, StringRef BaseName) : SSA(S) {
335  if (Insts.empty()) return;
336 
337  const Value *SomeVal;
338  if (const LoadInst *LI = dyn_cast<LoadInst>(Insts[0]))
339  SomeVal = LI;
340  else
341  SomeVal = cast<StoreInst>(Insts[0])->getOperand(0);
342 
343  if (BaseName.empty())
344  BaseName = SomeVal->getName();
345  SSA.Initialize(SomeVal->getType(), BaseName);
346 }
347 
349 run(const SmallVectorImpl<Instruction *> &Insts) const {
350  // First step: bucket up uses of the alloca by the block they occur in.
351  // This is important because we have to handle multiple defs/uses in a block
352  // ourselves: SSAUpdater is purely for cross-block references.
354 
355  for (Instruction *User : Insts)
356  UsesByBlock[User->getParent()].push_back(User);
357 
358  // Okay, now we can iterate over all the blocks in the function with uses,
359  // processing them. Keep track of which loads are loading a live-in value.
360  // Walk the uses in the use-list order to be determinstic.
361  SmallVector<LoadInst *, 32> LiveInLoads;
362  DenseMap<Value *, Value *> ReplacedLoads;
363 
364  for (Instruction *User : Insts) {
365  BasicBlock *BB = User->getParent();
366  TinyPtrVector<Instruction *> &BlockUses = UsesByBlock[BB];
367 
368  // If this block has already been processed, ignore this repeat use.
369  if (BlockUses.empty()) continue;
370 
371  // Okay, this is the first use in the block. If this block just has a
372  // single user in it, we can rewrite it trivially.
373  if (BlockUses.size() == 1) {
374  // If it is a store, it is a trivial def of the value in the block.
375  if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
377  SSA.AddAvailableValue(BB, SI->getOperand(0));
378  } else
379  // Otherwise it is a load, queue it to rewrite as a live-in load.
380  LiveInLoads.push_back(cast<LoadInst>(User));
381  BlockUses.clear();
382  continue;
383  }
384 
385  // Otherwise, check to see if this block is all loads.
386  bool HasStore = false;
387  for (Instruction *I : BlockUses) {
388  if (isa<StoreInst>(I)) {
389  HasStore = true;
390  break;
391  }
392  }
393 
394  // If so, we can queue them all as live in loads. We don't have an
395  // efficient way to tell which on is first in the block and don't want to
396  // scan large blocks, so just add all loads as live ins.
397  if (!HasStore) {
398  for (Instruction *I : BlockUses)
399  LiveInLoads.push_back(cast<LoadInst>(I));
400  BlockUses.clear();
401  continue;
402  }
403 
404  // Otherwise, we have mixed loads and stores (or just a bunch of stores).
405  // Since SSAUpdater is purely for cross-block values, we need to determine
406  // the order of these instructions in the block. If the first use in the
407  // block is a load, then it uses the live in value. The last store defines
408  // the live out value. We handle this by doing a linear scan of the block.
409  Value *StoredValue = nullptr;
410  for (Instruction &I : *BB) {
411  if (LoadInst *L = dyn_cast<LoadInst>(&I)) {
412  // If this is a load from an unrelated pointer, ignore it.
413  if (!isInstInList(L, Insts)) continue;
414 
415  // If we haven't seen a store yet, this is a live in use, otherwise
416  // use the stored value.
417  if (StoredValue) {
418  replaceLoadWithValue(L, StoredValue);
419  L->replaceAllUsesWith(StoredValue);
420  ReplacedLoads[L] = StoredValue;
421  } else {
422  LiveInLoads.push_back(L);
423  }
424  continue;
425  }
426 
427  if (StoreInst *SI = dyn_cast<StoreInst>(&I)) {
428  // If this is a store to an unrelated pointer, ignore it.
429  if (!isInstInList(SI, Insts)) continue;
431 
432  // Remember that this is the active value in the block.
433  StoredValue = SI->getOperand(0);
434  }
435  }
436 
437  // The last stored value that happened is the live-out for the block.
438  assert(StoredValue && "Already checked that there is a store in block");
439  SSA.AddAvailableValue(BB, StoredValue);
440  BlockUses.clear();
441  }
442 
443  // Okay, now we rewrite all loads that use live-in values in the loop,
444  // inserting PHI nodes as necessary.
445  for (LoadInst *ALoad : LiveInLoads) {
446  Value *NewVal = SSA.GetValueInMiddleOfBlock(ALoad->getParent());
447  replaceLoadWithValue(ALoad, NewVal);
448 
449  // Avoid assertions in unreachable code.
450  if (NewVal == ALoad) NewVal = UndefValue::get(NewVal->getType());
451  ALoad->replaceAllUsesWith(NewVal);
452  ReplacedLoads[ALoad] = NewVal;
453  }
454 
455  // Allow the client to do stuff before we start nuking things.
457 
458  // Now that everything is rewritten, delete the old instructions from the
459  // function. They should all be dead now.
460  for (Instruction *User : Insts) {
461  // If this is a load that still has uses, then the load must have been added
462  // as a live value in the SSAUpdate data structure for a block (e.g. because
463  // the loaded value was stored later). In this case, we need to recursively
464  // propagate the updates until we get to the real value.
465  if (!User->use_empty()) {
466  Value *NewVal = ReplacedLoads[User];
467  assert(NewVal && "not a replaced load?");
468 
469  // Propagate down to the ultimate replacee. The intermediately loads
470  // could theoretically already have been deleted, so we don't want to
471  // dereference the Value*'s.
472  DenseMap<Value*, Value*>::iterator RLI = ReplacedLoads.find(NewVal);
473  while (RLI != ReplacedLoads.end()) {
474  NewVal = RLI->second;
475  RLI = ReplacedLoads.find(NewVal);
476  }
477 
478  replaceLoadWithValue(cast<LoadInst>(User), NewVal);
479  User->replaceAllUsesWith(NewVal);
480  }
481 
483  User->eraseFromParent();
484  }
485 }
486 
487 bool
489  const SmallVectorImpl<Instruction *> &Insts)
490  const {
491  return is_contained(Insts, I);
492 }
SymbolTableList< Instruction >::iterator eraseFromParent()
This method unlinks &#39;this&#39; from the containing basic block and deletes it.
Definition: Instruction.cpp:68
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:225
void addIncoming(Value *V, BasicBlock *BB)
Add an incoming value to the end of the PHI list.
DenseMap< BasicBlock *, Value * > AvailableValsTy
Definition: SSAUpdater.cpp:41
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:283
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
Various leaf nodes.
Definition: ISDOpcodes.h:60
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
static BlkSucc_iterator BlkSucc_begin(BlkT *BB)
Definition: SSAUpdater.cpp:224
virtual void instructionDeleted(Instruction *I) const
Called before each instruction is deleted.
Definition: SSAUpdater.h:165
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:274
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:168
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:264
const Module * getModule() const
Return the module owning the function this basic block belongs to, or nullptr if the function does no...
Definition: BasicBlock.cpp:134
amdgpu Simplify well known AMD library false Value Value const Twine & Name
const DataLayout & getDataLayout() const
Get the data layout for the module&#39;s target platform.
Definition: Module.cpp:364
virtual bool isInstInList(Instruction *I, const SmallVectorImpl< Instruction *> &Insts) const
Return true if the specified instruction is in the Inst list.
Definition: SSAUpdater.cpp:488
static PHINode * InstrIsPHI(Instruction *I)
InstrIsPHI - Check if an instruction is a PHI.
Definition: SSAUpdater.cpp:289
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:246
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:103
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:158
bool operator==(const PHI_iterator &x) const
Definition: SSAUpdater.cpp:239
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:66
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:310
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:439
static void ValueIsRAUWd(Value *Old, Value *New)
Definition: Value.cpp:894
static Value * GetUndefVal(BasicBlock *BB, SSAUpdater *Updater)
GetUndefVal - Get an undefined value of the same type as the value being handled. ...
Definition: SSAUpdater.cpp:268
Interval::succ_iterator succ_end(Interval *I)
Definition: Interval.h:106
virtual void updateDebugInfo(Instruction *I) const
Called to update debug info associated with the instruction.
Definition: SSAUpdater.h:168
#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:189
void setDebugLoc(DebugLoc Loc)
Set the debug location information for this instruction.
Definition: Instruction.h:304
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:202
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator begin()
Definition: SmallVector.h:129
This file contains the declarations for the subclasses of Constant, which represent the different fla...
const Instruction & front() const
Definition: BasicBlock.h:276
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:113
bool empty() const
Interval::pred_iterator pred_end(Interval *I)
Definition: Interval.h:116
static UndefValue * get(Type *T)
Static factory methods - Return an &#39;undef&#39; object of the specified type.
Definition: Constants.cpp:1392
static AvailableValsTy & getAvailableVals(void *AV)
Definition: SSAUpdater.cpp:43
size_t size() const
Definition: SmallVector.h:53
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:294
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:253
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:847
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:349
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:133
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:162
void append(in_iter in_start, in_iter in_end)
Add the specified range to the end of the SmallVector.
Definition: SmallVector.h:394
This file provides various utilities for inspecting and working with the control flow graph in LLVM I...
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator end()
Definition: SmallVector.h:133
SuccIterator< Instruction, BasicBlock > succ_iterator
Definition: CFG.h:243
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:56
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:224
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
iterator_range< const_phi_iterator > phis() const
Returns a range that iterates over the phis in the basic block.
Definition: BasicBlock.h:320
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:142
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:247
bool operator!=(const PHI_iterator &x) const
Definition: SSAUpdater.cpp:240
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:333
bool operator==(uint64_t V1, const APInt &V2)
Definition: APInt.h:1961
Value * GetValueAtEndOfBlock(BasicBlock *BB)
Construct SSA form, materializing a value that is live at the end of the specified block...
Definition: SSAUpdater.cpp:90
#define LLVM_DEBUG(X)
Definition: Debug.h:123
void RewriteUse(Use &U)
Rewrite a use of the symbolic value.
Definition: SSAUpdater.cpp:185
static Value * GetPHIValue(PHINode *PHI)
GetPHIValue - For the specified PHI instruction, return the value that it defines.
Definition: SSAUpdater.cpp:309
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:300
bool use_empty() const
Definition: Value.h:323
unsigned size() const
bool empty() const
empty - Check if the array is empty.
Definition: ArrayRef.h:144
const BasicBlock * getParent() const
Definition: Instruction.h:67
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:1101