LLVM  3.7.0
LowerSwitch.cpp
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1 //===- LowerSwitch.cpp - Eliminate Switch instructions --------------------===//
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 // The LowerSwitch transformation rewrites switch instructions with a sequence
11 // of branches, which allows targets to get away with not implementing the
12 // switch instruction until it is convenient.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "llvm/Transforms/Scalar.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/IR/CFG.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/Function.h"
21 #include "llvm/IR/Instructions.h"
22 #include "llvm/IR/LLVMContext.h"
23 #include "llvm/Pass.h"
24 #include "llvm/Support/Compiler.h"
25 #include "llvm/Support/Debug.h"
29 #include <algorithm>
30 using namespace llvm;
31 
32 #define DEBUG_TYPE "lower-switch"
33 
34 namespace {
35  struct IntRange {
36  int64_t Low, High;
37  };
38  // Return true iff R is covered by Ranges.
39  static bool IsInRanges(const IntRange &R,
40  const std::vector<IntRange> &Ranges) {
41  // Note: Ranges must be sorted, non-overlapping and non-adjacent.
42 
43  // Find the first range whose High field is >= R.High,
44  // then check if the Low field is <= R.Low. If so, we
45  // have a Range that covers R.
46  auto I = std::lower_bound(
47  Ranges.begin(), Ranges.end(), R,
48  [](const IntRange &A, const IntRange &B) { return A.High < B.High; });
49  return I != Ranges.end() && I->Low <= R.Low;
50  }
51 
52  /// LowerSwitch Pass - Replace all SwitchInst instructions with chained branch
53  /// instructions.
54  class LowerSwitch : public FunctionPass {
55  public:
56  static char ID; // Pass identification, replacement for typeid
57  LowerSwitch() : FunctionPass(ID) {
59  }
60 
61  bool runOnFunction(Function &F) override;
62 
63  void getAnalysisUsage(AnalysisUsage &AU) const override {
64  // This is a cluster of orthogonal Transforms
67  }
68 
69  struct CaseRange {
70  ConstantInt* Low;
71  ConstantInt* High;
72  BasicBlock* BB;
73 
74  CaseRange(ConstantInt *low, ConstantInt *high, BasicBlock *bb)
75  : Low(low), High(high), BB(bb) {}
76  };
77 
78  typedef std::vector<CaseRange> CaseVector;
79  typedef std::vector<CaseRange>::iterator CaseItr;
80  private:
81  void processSwitchInst(SwitchInst *SI);
82 
83  BasicBlock *switchConvert(CaseItr Begin, CaseItr End,
84  ConstantInt *LowerBound, ConstantInt *UpperBound,
85  Value *Val, BasicBlock *Predecessor,
86  BasicBlock *OrigBlock, BasicBlock *Default,
87  const std::vector<IntRange> &UnreachableRanges);
88  BasicBlock *newLeafBlock(CaseRange &Leaf, Value *Val, BasicBlock *OrigBlock,
89  BasicBlock *Default);
90  unsigned Clusterify(CaseVector &Cases, SwitchInst *SI);
91  };
92 
93  /// The comparison function for sorting the switch case values in the vector.
94  /// WARNING: Case ranges should be disjoint!
95  struct CaseCmp {
96  bool operator () (const LowerSwitch::CaseRange& C1,
97  const LowerSwitch::CaseRange& C2) {
98 
99  const ConstantInt* CI1 = cast<const ConstantInt>(C1.Low);
100  const ConstantInt* CI2 = cast<const ConstantInt>(C2.High);
101  return CI1->getValue().slt(CI2->getValue());
102  }
103  };
104 }
105 
106 char LowerSwitch::ID = 0;
107 INITIALIZE_PASS(LowerSwitch, "lowerswitch",
108  "Lower SwitchInst's to branches", false, false)
109 
110 // Publicly exposed interface to pass...
111 char &llvm::LowerSwitchID = LowerSwitch::ID;
112 // createLowerSwitchPass - Interface to this file...
114  return new LowerSwitch();
115 }
116 
117 bool LowerSwitch::runOnFunction(Function &F) {
118  bool Changed = false;
119 
120  for (Function::iterator I = F.begin(), E = F.end(); I != E; ) {
121  BasicBlock *Cur = I++; // Advance over block so we don't traverse new blocks
122 
123  if (SwitchInst *SI = dyn_cast<SwitchInst>(Cur->getTerminator())) {
124  Changed = true;
125  processSwitchInst(SI);
126  }
127  }
128 
129  return Changed;
130 }
131 
132 // operator<< - Used for debugging purposes.
133 //
135  const LowerSwitch::CaseVector &C)
138  const LowerSwitch::CaseVector &C) {
139  O << "[";
140 
141  for (LowerSwitch::CaseVector::const_iterator B = C.begin(),
142  E = C.end(); B != E; ) {
143  O << *B->Low << " -" << *B->High;
144  if (++B != E) O << ", ";
145  }
146 
147  return O << "]";
148 }
149 
150 // \brief Update the first occurrence of the "switch statement" BB in the PHI
151 // node with the "new" BB. The other occurrences will:
152 //
153 // 1) Be updated by subsequent calls to this function. Switch statements may
154 // have more than one outcoming edge into the same BB if they all have the same
155 // value. When the switch statement is converted these incoming edges are now
156 // coming from multiple BBs.
157 // 2) Removed if subsequent incoming values now share the same case, i.e.,
158 // multiple outcome edges are condensed into one. This is necessary to keep the
159 // number of phi values equal to the number of branches to SuccBB.
160 static void fixPhis(BasicBlock *SuccBB, BasicBlock *OrigBB, BasicBlock *NewBB,
161  unsigned NumMergedCases) {
162  for (BasicBlock::iterator I = SuccBB->begin(), IE = SuccBB->getFirstNonPHI();
163  I != IE; ++I) {
164  PHINode *PN = cast<PHINode>(I);
165 
166  // Only update the first occurence.
167  unsigned Idx = 0, E = PN->getNumIncomingValues();
168  unsigned LocalNumMergedCases = NumMergedCases;
169  for (; Idx != E; ++Idx) {
170  if (PN->getIncomingBlock(Idx) == OrigBB) {
171  PN->setIncomingBlock(Idx, NewBB);
172  break;
173  }
174  }
175 
176  // Remove additional occurences coming from condensed cases and keep the
177  // number of incoming values equal to the number of branches to SuccBB.
178  SmallVector<unsigned, 8> Indices;
179  for (++Idx; LocalNumMergedCases > 0 && Idx < E; ++Idx)
180  if (PN->getIncomingBlock(Idx) == OrigBB) {
181  Indices.push_back(Idx);
182  LocalNumMergedCases--;
183  }
184  // Remove incoming values in the reverse order to prevent invalidating
185  // *successive* index.
186  for (auto III = Indices.rbegin(), IIE = Indices.rend(); III != IIE; ++III)
187  PN->removeIncomingValue(*III);
188  }
189 }
190 
191 // switchConvert - Convert the switch statement into a binary lookup of
192 // the case values. The function recursively builds this tree.
193 // LowerBound and UpperBound are used to keep track of the bounds for Val
194 // that have already been checked by a block emitted by one of the previous
195 // calls to switchConvert in the call stack.
196 BasicBlock *
197 LowerSwitch::switchConvert(CaseItr Begin, CaseItr End, ConstantInt *LowerBound,
198  ConstantInt *UpperBound, Value *Val,
199  BasicBlock *Predecessor, BasicBlock *OrigBlock,
201  const std::vector<IntRange> &UnreachableRanges) {
202  unsigned Size = End - Begin;
203 
204  if (Size == 1) {
205  // Check if the Case Range is perfectly squeezed in between
206  // already checked Upper and Lower bounds. If it is then we can avoid
207  // emitting the code that checks if the value actually falls in the range
208  // because the bounds already tell us so.
209  if (Begin->Low == LowerBound && Begin->High == UpperBound) {
210  unsigned NumMergedCases = 0;
211  if (LowerBound && UpperBound)
212  NumMergedCases =
213  UpperBound->getSExtValue() - LowerBound->getSExtValue();
214  fixPhis(Begin->BB, OrigBlock, Predecessor, NumMergedCases);
215  return Begin->BB;
216  }
217  return newLeafBlock(*Begin, Val, OrigBlock, Default);
218  }
219 
220  unsigned Mid = Size / 2;
221  std::vector<CaseRange> LHS(Begin, Begin + Mid);
222  DEBUG(dbgs() << "LHS: " << LHS << "\n");
223  std::vector<CaseRange> RHS(Begin + Mid, End);
224  DEBUG(dbgs() << "RHS: " << RHS << "\n");
225 
226  CaseRange &Pivot = *(Begin + Mid);
227  DEBUG(dbgs() << "Pivot ==> "
228  << Pivot.Low->getValue()
229  << " -" << Pivot.High->getValue() << "\n");
230 
231  // NewLowerBound here should never be the integer minimal value.
232  // This is because it is computed from a case range that is never
233  // the smallest, so there is always a case range that has at least
234  // a smaller value.
235  ConstantInt *NewLowerBound = Pivot.Low;
236 
237  // Because NewLowerBound is never the smallest representable integer
238  // it is safe here to subtract one.
239  ConstantInt *NewUpperBound = ConstantInt::get(NewLowerBound->getContext(),
240  NewLowerBound->getValue() - 1);
241 
242  if (!UnreachableRanges.empty()) {
243  // Check if the gap between LHS's highest and NewLowerBound is unreachable.
244  int64_t GapLow = LHS.back().High->getSExtValue() + 1;
245  int64_t GapHigh = NewLowerBound->getSExtValue() - 1;
246  IntRange Gap = { GapLow, GapHigh };
247  if (GapHigh >= GapLow && IsInRanges(Gap, UnreachableRanges))
248  NewUpperBound = LHS.back().High;
249  }
250 
251  DEBUG(dbgs() << "LHS Bounds ==> ";
252  if (LowerBound) {
253  dbgs() << LowerBound->getSExtValue();
254  } else {
255  dbgs() << "NONE";
256  }
257  dbgs() << " - " << NewUpperBound->getSExtValue() << "\n";
258  dbgs() << "RHS Bounds ==> ";
259  dbgs() << NewLowerBound->getSExtValue() << " - ";
260  if (UpperBound) {
261  dbgs() << UpperBound->getSExtValue() << "\n";
262  } else {
263  dbgs() << "NONE\n";
264  });
265 
266  // Create a new node that checks if the value is < pivot. Go to the
267  // left branch if it is and right branch if not.
268  Function* F = OrigBlock->getParent();
269  BasicBlock* NewNode = BasicBlock::Create(Val->getContext(), "NodeBlock");
270 
272  Val, Pivot.Low, "Pivot");
273 
274  BasicBlock *LBranch = switchConvert(LHS.begin(), LHS.end(), LowerBound,
275  NewUpperBound, Val, NewNode, OrigBlock,
276  Default, UnreachableRanges);
277  BasicBlock *RBranch = switchConvert(RHS.begin(), RHS.end(), NewLowerBound,
278  UpperBound, Val, NewNode, OrigBlock,
279  Default, UnreachableRanges);
280 
281  Function::iterator FI = OrigBlock;
282  F->getBasicBlockList().insert(++FI, NewNode);
283  NewNode->getInstList().push_back(Comp);
284 
285  BranchInst::Create(LBranch, RBranch, Comp, NewNode);
286  return NewNode;
287 }
288 
289 // newLeafBlock - Create a new leaf block for the binary lookup tree. It
290 // checks if the switch's value == the case's value. If not, then it
291 // jumps to the default branch. At this point in the tree, the value
292 // can't be another valid case value, so the jump to the "default" branch
293 // is warranted.
294 //
295 BasicBlock* LowerSwitch::newLeafBlock(CaseRange& Leaf, Value* Val,
296  BasicBlock* OrigBlock,
297  BasicBlock* Default)
298 {
299  Function* F = OrigBlock->getParent();
300  BasicBlock* NewLeaf = BasicBlock::Create(Val->getContext(), "LeafBlock");
301  Function::iterator FI = OrigBlock;
302  F->getBasicBlockList().insert(++FI, NewLeaf);
303 
304  // Emit comparison
305  ICmpInst* Comp = nullptr;
306  if (Leaf.Low == Leaf.High) {
307  // Make the seteq instruction...
308  Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_EQ, Val,
309  Leaf.Low, "SwitchLeaf");
310  } else {
311  // Make range comparison
312  if (Leaf.Low->isMinValue(true /*isSigned*/)) {
313  // Val >= Min && Val <= Hi --> Val <= Hi
314  Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_SLE, Val, Leaf.High,
315  "SwitchLeaf");
316  } else if (Leaf.Low->isZero()) {
317  // Val >= 0 && Val <= Hi --> Val <=u Hi
318  Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_ULE, Val, Leaf.High,
319  "SwitchLeaf");
320  } else {
321  // Emit V-Lo <=u Hi-Lo
322  Constant* NegLo = ConstantExpr::getNeg(Leaf.Low);
323  Instruction* Add = BinaryOperator::CreateAdd(Val, NegLo,
324  Val->getName()+".off",
325  NewLeaf);
326  Constant *UpperBound = ConstantExpr::getAdd(NegLo, Leaf.High);
327  Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_ULE, Add, UpperBound,
328  "SwitchLeaf");
329  }
330  }
331 
332  // Make the conditional branch...
333  BasicBlock* Succ = Leaf.BB;
334  BranchInst::Create(Succ, Default, Comp, NewLeaf);
335 
336  // If there were any PHI nodes in this successor, rewrite one entry
337  // from OrigBlock to come from NewLeaf.
338  for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) {
339  PHINode* PN = cast<PHINode>(I);
340  // Remove all but one incoming entries from the cluster
341  uint64_t Range = Leaf.High->getSExtValue() -
342  Leaf.Low->getSExtValue();
343  for (uint64_t j = 0; j < Range; ++j) {
344  PN->removeIncomingValue(OrigBlock);
345  }
346 
347  int BlockIdx = PN->getBasicBlockIndex(OrigBlock);
348  assert(BlockIdx != -1 && "Switch didn't go to this successor??");
349  PN->setIncomingBlock((unsigned)BlockIdx, NewLeaf);
350  }
351 
352  return NewLeaf;
353 }
354 
355 // Clusterify - Transform simple list of Cases into list of CaseRange's
356 unsigned LowerSwitch::Clusterify(CaseVector& Cases, SwitchInst *SI) {
357  unsigned numCmps = 0;
358 
359  // Start with "simple" cases
360  for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end(); i != e; ++i)
361  Cases.push_back(CaseRange(i.getCaseValue(), i.getCaseValue(),
362  i.getCaseSuccessor()));
363 
364  std::sort(Cases.begin(), Cases.end(), CaseCmp());
365 
366  // Merge case into clusters
367  if (Cases.size() >= 2) {
368  CaseItr I = Cases.begin();
369  for (CaseItr J = std::next(I), E = Cases.end(); J != E; ++J) {
370  int64_t nextValue = J->Low->getSExtValue();
371  int64_t currentValue = I->High->getSExtValue();
372  BasicBlock* nextBB = J->BB;
373  BasicBlock* currentBB = I->BB;
374 
375  // If the two neighboring cases go to the same destination, merge them
376  // into a single case.
377  assert(nextValue > currentValue && "Cases should be strictly ascending");
378  if ((nextValue == currentValue + 1) && (currentBB == nextBB)) {
379  I->High = J->High;
380  // FIXME: Combine branch weights.
381  } else if (++I != J) {
382  *I = *J;
383  }
384  }
385  Cases.erase(std::next(I), Cases.end());
386  }
387 
388  for (CaseItr I=Cases.begin(), E=Cases.end(); I!=E; ++I, ++numCmps) {
389  if (I->Low != I->High)
390  // A range counts double, since it requires two compares.
391  ++numCmps;
392  }
393 
394  return numCmps;
395 }
396 
397 // processSwitchInst - Replace the specified switch instruction with a sequence
398 // of chained if-then insts in a balanced binary search.
399 //
400 void LowerSwitch::processSwitchInst(SwitchInst *SI) {
401  BasicBlock *CurBlock = SI->getParent();
402  BasicBlock *OrigBlock = CurBlock;
403  Function *F = CurBlock->getParent();
404  Value *Val = SI->getCondition(); // The value we are switching on...
405  BasicBlock* Default = SI->getDefaultDest();
406 
407  // If there is only the default destination, just branch.
408  if (!SI->getNumCases()) {
409  BranchInst::Create(Default, CurBlock);
410  SI->eraseFromParent();
411  return;
412  }
413 
414  // Prepare cases vector.
415  CaseVector Cases;
416  unsigned numCmps = Clusterify(Cases, SI);
417  DEBUG(dbgs() << "Clusterify finished. Total clusters: " << Cases.size()
418  << ". Total compares: " << numCmps << "\n");
419  DEBUG(dbgs() << "Cases: " << Cases << "\n");
420  (void)numCmps;
421 
422  ConstantInt *LowerBound = nullptr;
423  ConstantInt *UpperBound = nullptr;
424  std::vector<IntRange> UnreachableRanges;
425 
426  if (isa<UnreachableInst>(Default->getFirstNonPHIOrDbg())) {
427  // Make the bounds tightly fitted around the case value range, becase we
428  // know that the value passed to the switch must be exactly one of the case
429  // values.
430  assert(!Cases.empty());
431  LowerBound = Cases.front().Low;
432  UpperBound = Cases.back().High;
433 
435  unsigned MaxPop = 0;
436  BasicBlock *PopSucc = nullptr;
437 
438  IntRange R = { INT64_MIN, INT64_MAX };
439  UnreachableRanges.push_back(R);
440  for (const auto &I : Cases) {
441  int64_t Low = I.Low->getSExtValue();
442  int64_t High = I.High->getSExtValue();
443 
444  IntRange &LastRange = UnreachableRanges.back();
445  if (LastRange.Low == Low) {
446  // There is nothing left of the previous range.
447  UnreachableRanges.pop_back();
448  } else {
449  // Terminate the previous range.
450  assert(Low > LastRange.Low);
451  LastRange.High = Low - 1;
452  }
453  if (High != INT64_MAX) {
454  IntRange R = { High + 1, INT64_MAX };
455  UnreachableRanges.push_back(R);
456  }
457 
458  // Count popularity.
459  int64_t N = High - Low + 1;
460  unsigned &Pop = Popularity[I.BB];
461  if ((Pop += N) > MaxPop) {
462  MaxPop = Pop;
463  PopSucc = I.BB;
464  }
465  }
466 #ifndef NDEBUG
467  /* UnreachableRanges should be sorted and the ranges non-adjacent. */
468  for (auto I = UnreachableRanges.begin(), E = UnreachableRanges.end();
469  I != E; ++I) {
470  assert(I->Low <= I->High);
471  auto Next = I + 1;
472  if (Next != E) {
473  assert(Next->Low > I->High);
474  }
475  }
476 #endif
477 
478  // Use the most popular block as the new default, reducing the number of
479  // cases.
480  assert(MaxPop > 0 && PopSucc);
481  Default = PopSucc;
482  Cases.erase(std::remove_if(
483  Cases.begin(), Cases.end(),
484  [PopSucc](const CaseRange &R) { return R.BB == PopSucc; }),
485  Cases.end());
486 
487  // If there are no cases left, just branch.
488  if (Cases.empty()) {
489  BranchInst::Create(Default, CurBlock);
490  SI->eraseFromParent();
491  return;
492  }
493  }
494 
495  // Create a new, empty default block so that the new hierarchy of
496  // if-then statements go to this and the PHI nodes are happy.
497  BasicBlock *NewDefault = BasicBlock::Create(SI->getContext(), "NewDefault");
498  F->getBasicBlockList().insert(Default, NewDefault);
499  BranchInst::Create(Default, NewDefault);
500 
501  // If there is an entry in any PHI nodes for the default edge, make sure
502  // to update them as well.
503  for (BasicBlock::iterator I = Default->begin(); isa<PHINode>(I); ++I) {
504  PHINode *PN = cast<PHINode>(I);
505  int BlockIdx = PN->getBasicBlockIndex(OrigBlock);
506  assert(BlockIdx != -1 && "Switch didn't go to this successor??");
507  PN->setIncomingBlock((unsigned)BlockIdx, NewDefault);
508  }
509 
510  BasicBlock *SwitchBlock =
511  switchConvert(Cases.begin(), Cases.end(), LowerBound, UpperBound, Val,
512  OrigBlock, OrigBlock, NewDefault, UnreachableRanges);
513 
514  // Branch to our shiny new if-then stuff...
515  BranchInst::Create(SwitchBlock, OrigBlock);
516 
517  // We are now done with the switch instruction, delete it.
518  BasicBlock *OldDefault = SI->getDefaultDest();
519  CurBlock->getInstList().erase(SI);
520 
521  // If the Default block has no more predecessors just remove it.
522  if (pred_begin(OldDefault) == pred_end(OldDefault))
523  DeleteDeadBlock(OldDefault);
524 }
iplist< Instruction >::iterator eraseFromParent()
eraseFromParent - This method unlinks 'this' from the containing basic block and deletes it...
Definition: Instruction.cpp:70
void push_back(const T &Elt)
Definition: SmallVector.h:222
CaseIt case_end()
Returns a read/write iterator that points one past the last in the SwitchInst.
AnalysisUsage & addPreserved()
Add the specified Pass class to the set of analyses preserved by this pass.
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
const Instruction & back() const
Definition: BasicBlock.h:245
FunctionPass * createLowerSwitchPass()
iterator end()
Definition: Function.h:459
void DeleteDeadBlock(BasicBlock *BB)
DeleteDeadBlock - Delete the specified block, which must have no predecessors.
CaseIt case_begin()
Returns a read/write iterator that points to the first case in SwitchInst.
unsigned less or equal
Definition: InstrTypes.h:723
const Function * getParent() const
Return the enclosing method, or null if none.
Definition: BasicBlock.h:111
F(f)
char & LowerSwitchID
StringRef getName() const
Return a constant reference to the value's name.
Definition: Value.cpp:188
iterator begin()
Instruction iterator methods.
Definition: BasicBlock.h:231
static Constant * getAdd(Constant *C1, Constant *C2, bool HasNUW=false, bool HasNSW=false)
Definition: Constants.cpp:2258
Instruction * getFirstNonPHIOrDbg()
Returns a pointer to the first instruction in this block that is not a PHINode or a debug intrinsic...
Definition: BasicBlock.cpp:172
Value * removeIncomingValue(unsigned Idx, bool DeletePHIIfEmpty=true)
removeIncomingValue - Remove an incoming value.
const APInt & getValue() const
Return the constant as an APInt value reference.
Definition: Constants.h:106
Instruction * getFirstNonPHI()
Returns a pointer to the first instruction in this block that is not a PHINode instruction.
Definition: BasicBlock.cpp:165
AnalysisUsage & addPreservedID(const void *ID)
iterator begin()
Definition: Function.h:457
static BinaryOperator * CreateAdd(Value *S1, Value *S2, const Twine &Name, Instruction *InsertBefore, Value *FlagsOp)
unsigned getNumIncomingValues() const
getNumIncomingValues - Return the number of incoming edges
LLVM Basic Block Representation.
Definition: BasicBlock.h:65
This is an important base class in LLVM.
Definition: Constant.h:41
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:114
static void fixPhis(BasicBlock *SuccBB, BasicBlock *OrigBB, BasicBlock *NewBB, unsigned NumMergedCases)
Represent the analysis usage information of a pass.
BasicBlock * getIncomingBlock(unsigned i) const
getIncomingBlock - Return incoming basic block number i.
const InstListType & getInstList() const
Return the underlying instruction list container.
Definition: BasicBlock.h:252
This instruction compares its operands according to the predicate given to the constructor.
iterator insert(iterator where, NodeTy *New)
Definition: ilist.h:412
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:294
Interval::pred_iterator pred_end(Interval *I)
Definition: Interval.h:117
static BasicBlock * Create(LLVMContext &Context, const Twine &Name="", Function *Parent=nullptr, BasicBlock *InsertBefore=nullptr)
Creates a new BasicBlock.
Definition: BasicBlock.h:103
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:519
iterator erase(iterator where)
Definition: ilist.h:465
char & LowerInvokePassID
#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)
Definition: PassSupport.h:56
const BasicBlockListType & getBasicBlockList() const
Definition: Function.h:436
This is the shared class of boolean and integer constants.
Definition: Constants.h:47
void setIncomingBlock(unsigned i, BasicBlock *BB)
bool slt(const APInt &RHS) const
Signed less than comparison.
Definition: APInt.cpp:552
signed less than
Definition: InstrTypes.h:726
static Constant * get(Type *Ty, uint64_t V, bool isSigned=false)
If Ty is a vector type, return a Constant with a splat of the given value.
Definition: Constants.cpp:582
static BranchInst * Create(BasicBlock *IfTrue, Instruction *InsertBefore=nullptr)
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:123
signed less or equal
Definition: InstrTypes.h:727
Value * getCondition() const
SI Fix SGPR Live Ranges
static Constant * getNeg(Constant *C, bool HasNUW=false, bool HasNSW=false)
Definition: Constants.cpp:2239
BasicBlock * getDefaultDest() const
#define I(x, y, z)
Definition: MD5.cpp:54
#define N
TerminatorInst * getTerminator()
Returns the terminator instruction if the block is well formed or null if the block is not well forme...
Definition: BasicBlock.cpp:124
raw_ostream & operator<<(raw_ostream &OS, const APInt &I)
Definition: APInt.h:1738
unsigned getNumCases() const
getNumCases - return the number of 'cases' in this switch instruction, except the default case ...
SwitchInst - Multiway switch.
LLVM Value Representation.
Definition: Value.h:69
void initializeLowerSwitchPass(PassRegistry &)
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:38
#define DEBUG(X)
Definition: Debug.h:92
int64_t getSExtValue() const
Return the constant as a 64-bit integer value after it has been sign extended as appropriate for the ...
Definition: Constants.h:125
int getBasicBlockIndex(const BasicBlock *BB) const
getBasicBlockIndex - Return the first index of the specified basic block in the value list for this P...
const BasicBlock * getParent() const
Definition: Instruction.h:72
#define LLVM_ATTRIBUTE_USED
Definition: Compiler.h:122