C++ (Cpp) ICmpInst::getContext Examples

Example #1

void IndVarSimplify::EliminateIVComparisons() {
  // Look for ICmp users.
  for (IVUsers::iterator I = IU->begin(), E = IU->end(); I != E; ++I) {
    IVStrideUse &UI = *I;
    ICmpInst *ICmp = dyn_cast<ICmpInst>(UI.getUser());
    if (!ICmp) continue;

    bool Swapped = UI.getOperandValToReplace() == ICmp->getOperand(1);
    ICmpInst::Predicate Pred = ICmp->getPredicate();
    if (Swapped) Pred = ICmpInst::getSwappedPredicate(Pred);

    // Get the SCEVs for the ICmp operands.
    const SCEV *S = IU->getReplacementExpr(UI);
    const SCEV *X = SE->getSCEV(ICmp->getOperand(!Swapped));

    // Simplify unnecessary loops away.
    const Loop *ICmpLoop = LI->getLoopFor(ICmp->getParent());
    S = SE->getSCEVAtScope(S, ICmpLoop);
    X = SE->getSCEVAtScope(X, ICmpLoop);

    // If the condition is always true or always false, replace it with
    // a constant value.
    if (SE->isKnownPredicate(Pred, S, X))
      ICmp->replaceAllUsesWith(ConstantInt::getTrue(ICmp->getContext()));
    else if (SE->isKnownPredicate(ICmpInst::getInversePredicate(Pred), S, X))
      ICmp->replaceAllUsesWith(ConstantInt::getFalse(ICmp->getContext()));
    else
      continue;

    DEBUG(dbgs() << "INDVARS: Eliminated comparison: " << *ICmp << '\n');
    DeadInsts.push_back(ICmp);
  }
}

Example #2

File: IndVarSimplify.cpp Project: 5432935/crossbridge

void IndVarSimplify::EliminateIVComparisons() {
  SmallVector<WeakVH, 16> DeadInsts;

  // Look for ICmp users.
  for (IVUsers::iterator I = IU->begin(), E = IU->end(); I != E; ++I) {
    IVStrideUse &UI = *I;
    ICmpInst *ICmp = dyn_cast<ICmpInst>(UI.getUser());
    if (!ICmp) continue;

    bool Swapped = UI.getOperandValToReplace() == ICmp->getOperand(1);
    ICmpInst::Predicate Pred = ICmp->getPredicate();
    if (Swapped) Pred = ICmpInst::getSwappedPredicate(Pred);

    // Get the SCEVs for the ICmp operands.
    const SCEV *S = IU->getReplacementExpr(UI);
    const SCEV *X = SE->getSCEV(ICmp->getOperand(!Swapped));

    // Simplify unnecessary loops away.
    const Loop *ICmpLoop = LI->getLoopFor(ICmp->getParent());
    S = SE->getSCEVAtScope(S, ICmpLoop);
    X = SE->getSCEVAtScope(X, ICmpLoop);

    // If the condition is always true or always false, replace it with
    // a constant value.
    if (SE->isKnownPredicate(Pred, S, X))
      ICmp->replaceAllUsesWith(ConstantInt::getTrue(ICmp->getContext()));
    else if (SE->isKnownPredicate(ICmpInst::getInversePredicate(Pred), S, X))
      ICmp->replaceAllUsesWith(ConstantInt::getFalse(ICmp->getContext()));
    else
      continue;

    DEBUG(dbgs() << "INDVARS: Eliminated comparison: " << *ICmp << '\n');
    DeadInsts.push_back(ICmp);
  }

  // Now that we're done iterating through lists, clean up any instructions
  // which are now dead.
  while (!DeadInsts.empty())
    if (Instruction *Inst =
        dyn_cast_or_null<Instruction>(&*DeadInsts.pop_back_val()))
      RecursivelyDeleteTriviallyDeadInstructions(Inst);
}

Example #3

File: LoopIndexSplit.cpp Project: aaasz/SHP

/// restrictLoopBound - Op dominates loop body. Op compares an IV based value 
/// with a loop invariant value. Update loop's lower and upper bound based on 
/// the loop invariant value.
bool LoopIndexSplit::restrictLoopBound(ICmpInst &Op) {
  bool Sign = Op.isSigned();
  Instruction *PHTerm = L->getLoopPreheader()->getTerminator();

  if (IVisGT(*ExitCondition) || IVisGE(*ExitCondition)) {
    BranchInst *EBR = 
      cast<BranchInst>(ExitCondition->getParent()->getTerminator());
    ExitCondition->setPredicate(ExitCondition->getInversePredicate());
    BasicBlock *T = EBR->getSuccessor(0);
    EBR->setSuccessor(0, EBR->getSuccessor(1));
    EBR->setSuccessor(1, T);
  }

  LLVMContext &Context = Op.getContext();

  // New upper and lower bounds.
  Value *NLB = NULL;
  Value *NUB = NULL;
  if (Value *V = IVisLT(Op)) {
    // Restrict upper bound.
    if (IVisLE(*ExitCondition)) 
      V = getMinusOne(V, Sign, PHTerm, Context);
    NUB = getMin(V, IVExitValue, Sign, PHTerm);
  } else if (Value *V = IVisLE(Op)) {
    // Restrict upper bound.
    if (IVisLT(*ExitCondition)) 
      V = getPlusOne(V, Sign, PHTerm, Context);
    NUB = getMin(V, IVExitValue, Sign, PHTerm);
  } else if (Value *V = IVisGT(Op)) {
    // Restrict lower bound.
    V = getPlusOne(V, Sign, PHTerm, Context);
    NLB = getMax(V, IVStartValue, Sign, PHTerm);
  } else if (Value *V = IVisGE(Op))
    // Restrict lower bound.
    NLB = getMax(V, IVStartValue, Sign, PHTerm);

  if (!NLB && !NUB) 
    return false;

  if (NLB) {
    unsigned i = IndVar->getBasicBlockIndex(L->getLoopPreheader());
    IndVar->setIncomingValue(i, NLB);
  }

  if (NUB) {
    unsigned i = (ExitCondition->getOperand(0) != IVExitValue);
    ExitCondition->setOperand(i, NUB);
  }
  return true;
}