C++ SelectInst::getOperand方法代码示例

bool AMDGPUCodeGenPrepare::promoteUniformOpToI32(SelectInst &I) const {
  assert(needsPromotionToI32(I.getType()) &&
         "I does not need promotion to i32");

  IRBuilder<> Builder(&I);
  Builder.SetCurrentDebugLocation(I.getDebugLoc());

  Type *I32Ty = getI32Ty(Builder, I.getType());
  Value *ExtOp1 = nullptr;
  Value *ExtOp2 = nullptr;
  Value *ExtRes = nullptr;
  Value *TruncRes = nullptr;

  if (isSigned(I)) {
    ExtOp1 = Builder.CreateSExt(I.getOperand(1), I32Ty);
    ExtOp2 = Builder.CreateSExt(I.getOperand(2), I32Ty);
  } else {
    ExtOp1 = Builder.CreateZExt(I.getOperand(1), I32Ty);
    ExtOp2 = Builder.CreateZExt(I.getOperand(2), I32Ty);
  }
  ExtRes = Builder.CreateSelect(I.getOperand(0), ExtOp1, ExtOp2);
  TruncRes = Builder.CreateTrunc(ExtRes, I.getType());

  I.replaceAllUsesWith(TruncRes);
  I.eraseFromParent();

  return true;
}

bool Scalarizer::visitSelectInst(SelectInst &SI) {
  VectorType *VT = dyn_cast<VectorType>(SI.getType());
  if (!VT)
    return false;

  unsigned NumElems = VT->getNumElements();
  IRBuilder<> Builder(SI.getParent(), &SI);
  Scatterer Op1 = scatter(&SI, SI.getOperand(1));
  Scatterer Op2 = scatter(&SI, SI.getOperand(2));
  assert(Op1.size() == NumElems && "Mismatched select");
  assert(Op2.size() == NumElems && "Mismatched select");
  ValueVector Res;
  Res.resize(NumElems);

  if (SI.getOperand(0)->getType()->isVectorTy()) {
    Scatterer Op0 = scatter(&SI, SI.getOperand(0));
    assert(Op0.size() == NumElems && "Mismatched select");
    for (unsigned I = 0; I < NumElems; ++I)
      Res[I] = Builder.CreateSelect(Op0[I], Op1[I], Op2[I],
                                    SI.getName() + ".i" + Twine(I));
  } else {
    Value *Op0 = SI.getOperand(0);
    for (unsigned I = 0; I < NumElems; ++I)
      Res[I] = Builder.CreateSelect(Op0, Op1[I], Op2[I],
                                    SI.getName() + ".i" + Twine(I));
  }
  gather(&SI, Res);
  return true;
}

void Interpreter::visitSelectInst(SelectInst &I) {
  ExecutionContext &SF = ECStack.back();
  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
  GenericValue Src3 = getOperandValue(I.getOperand(2), SF);
  GenericValue R = executeSelectInst(Src1, Src2, Src3);
  SetValue(&I, R, SF);
}

// -- handle select instruction -- 
void UnsafeTypeCastingCheck::handleSelectInstruction (Instruction *inst) {
  SelectInst *sinst = dyn_cast<SelectInst>(inst); 
  if (sinst == NULL) 
    utccAbort("handleSelectInstruction cannot process with a non-select instruction");       
  assert(sinst->getNumOperands() == 3); 
  Value *choice0 = sinst->getOperand(1); 
  Value *choice1 = sinst->getOperand(2); 
  Type *type0 = choice0->getType();
  Type *type1 = choice1->getType(); 
  UTCC_TYPE ut0 = llvmT2utccT(type0, choice0); 
  UTCC_TYPE ut1 = llvmT2utccT(type1, choice1); 

  if (type0->isIntegerTy() && 
      type1->isIntegerTy()) {
    if (ut0 == ut1) 
      setExprType(sinst, ut0); 
    else if (ut0 == INT_UT || ut1 == INT_UT) 
      setExprType(sinst, INT_UT); 
    else setExprType(sinst, NINT_UT); 
  }
  else if (type0->isFloatingPointTy() && 
	   type1->isFloatingPointTy()) {
    if (ut0 == ut1) 
      setExprType(sinst, ut0); 
    else if (ut0 == FP_UT || ut1 == FP_UT) 
      setExprType(sinst, FP_UT); 
    else setExprType(sinst, NFP_UT); 
  }
  else {
    setExprType(sinst, llvmT2utccT(sinst->getType(), sinst)); 
  }
}

void GraphBuilder::visitSelectInst(SelectInst &SI) {
  if (!isa<PointerType>(SI.getType()))
    return; // Only pointer Selects

  DSNodeHandle &Dest = G.getNodeForValue(&SI);
  DSNodeHandle S1 = getValueDest(SI.getOperand(1));
  DSNodeHandle S2 = getValueDest(SI.getOperand(2));
  Dest.mergeWith(S1);
  Dest.mergeWith(S2);
}

/// SimplifyDivRemOfSelect - Try to fold a divide or remainder of a select
/// instruction.
bool InstCombiner::SimplifyDivRemOfSelect(BinaryOperator &I) {
  SelectInst *SI = cast<SelectInst>(I.getOperand(1));
  
  // div/rem X, (Cond ? 0 : Y) -> div/rem X, Y
  int NonNullOperand = -1;
  if (Constant *ST = dyn_cast<Constant>(SI->getOperand(1)))
    if (ST->isNullValue())
      NonNullOperand = 2;
  // div/rem X, (Cond ? Y : 0) -> div/rem X, Y
  if (Constant *ST = dyn_cast<Constant>(SI->getOperand(2)))
    if (ST->isNullValue())
      NonNullOperand = 1;
  
  if (NonNullOperand == -1)
    return false;
  
  Value *SelectCond = SI->getOperand(0);
  
  // Change the div/rem to use 'Y' instead of the select.
  I.setOperand(1, SI->getOperand(NonNullOperand));
  
  // Okay, we know we replace the operand of the div/rem with 'Y' with no
  // problem.  However, the select, or the condition of the select may have
  // multiple uses.  Based on our knowledge that the operand must be non-zero,
  // propagate the known value for the select into other uses of it, and
  // propagate a known value of the condition into its other users.
  
  // If the select and condition only have a single use, don't bother with this,
  // early exit.
  if (SI->use_empty() && SelectCond->hasOneUse())
    return true;
  
  // Scan the current block backward, looking for other uses of SI.
  BasicBlock::iterator BBI = &I, BBFront = I.getParent()->begin();
  
  while (BBI != BBFront) {
    --BBI;
    // If we found a call to a function, we can't assume it will return, so
    // information from below it cannot be propagated above it.
    if (isa<CallInst>(BBI) && !isa<IntrinsicInst>(BBI))
      break;
    
    // Replace uses of the select or its condition with the known values.
    for (Instruction::op_iterator I = BBI->op_begin(), E = BBI->op_end();
         I != E; ++I) {
      if (*I == SI) {
        *I = SI->getOperand(NonNullOperand);
        Worklist.Add(BBI);
      } else if (*I == SelectCond) {
        *I = NonNullOperand == 1 ? ConstantInt::getTrue(BBI->getContext()) :
                                   ConstantInt::getFalse(BBI->getContext());
        Worklist.Add(BBI);
      }
    }
    
    // If we past the instruction, quit looking for it.
    if (&*BBI == SI)
      SI = 0;
    if (&*BBI == SelectCond)
      SelectCond = 0;
    
    // If we ran out of things to eliminate, break out of the loop.
    if (SelectCond == 0 && SI == 0)
      break;
    
  }
  return true;
}

bool AMDGPUCodeGenPrepare::isSigned(const SelectInst &I) const {
  return isa<ICmpInst>(I.getOperand(0)) ?
      cast<ICmpInst>(I.getOperand(0))->isSigned() : false;
}