C++ ConstantInt::getType方法代码示例

bool InductionDescriptor::isInductionPHI(PHINode *Phi, const Loop *TheLoop,
        ScalarEvolution *SE,
        InductionDescriptor &D,
        const SCEV *Expr) {
    Type *PhiTy = Phi->getType();
    // We only handle integer and pointer inductions variables.
    if (!PhiTy->isIntegerTy() && !PhiTy->isPointerTy())
        return false;

    // Check that the PHI is consecutive.
    const SCEV *PhiScev = Expr ? Expr : SE->getSCEV(Phi);
    const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PhiScev);

    if (!AR) {
        DEBUG(dbgs() << "LV: PHI is not a poly recurrence.\n");
        return false;
    }

    assert(TheLoop->getHeader() == Phi->getParent() &&
           "PHI is an AddRec for a different loop?!");
    Value *StartValue =
        Phi->getIncomingValueForBlock(AR->getLoop()->getLoopPreheader());
    const SCEV *Step = AR->getStepRecurrence(*SE);
    // Calculate the pointer stride and check if it is consecutive.
    // The stride may be a constant or a loop invariant integer value.
    const SCEVConstant *ConstStep = dyn_cast<SCEVConstant>(Step);
    if (!ConstStep && !SE->isLoopInvariant(Step, TheLoop))
        return false;

    if (PhiTy->isIntegerTy()) {
        D = InductionDescriptor(StartValue, IK_IntInduction, Step);
        return true;
    }

    assert(PhiTy->isPointerTy() && "The PHI must be a pointer");
    // Pointer induction should be a constant.
    if (!ConstStep)
        return false;

    ConstantInt *CV = ConstStep->getValue();
    Type *PointerElementType = PhiTy->getPointerElementType();
    // The pointer stride cannot be determined if the pointer element type is not
    // sized.
    if (!PointerElementType->isSized())
        return false;

    const DataLayout &DL = Phi->getModule()->getDataLayout();
    int64_t Size = static_cast<int64_t>(DL.getTypeAllocSize(PointerElementType));
    if (!Size)
        return false;

    int64_t CVSize = CV->getSExtValue();
    if (CVSize % Size)
        return false;
    auto *StepValue = SE->getConstant(CV->getType(), CVSize / Size,
                                      true /* signed */);
    D = InductionDescriptor(StartValue, IK_PtrInduction, StepValue);
    return true;
}

bool llvm::decomposeBitTestICmp(const ICmpInst *I, CmpInst::Predicate &Pred,
                                Value *&X, Value *&Y, Value *&Z) {
  ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1));
  if (!C)
    return false;

  switch (I->getPredicate()) {
  default:
    return false;
  case ICmpInst::ICMP_SLT:
    // X < 0 is equivalent to (X & SignBit) != 0.
    if (!C->isZero())
      return false;
    Y = ConstantInt::get(I->getContext(), APInt::getSignBit(C->getBitWidth()));
    Pred = ICmpInst::ICMP_NE;
    break;
  case ICmpInst::ICMP_SGT:
    // X > -1 is equivalent to (X & SignBit) == 0.
    if (!C->isAllOnesValue())
      return false;
    Y = ConstantInt::get(I->getContext(), APInt::getSignBit(C->getBitWidth()));
    Pred = ICmpInst::ICMP_EQ;
    break;
  case ICmpInst::ICMP_ULT:
    // X <u 2^n is equivalent to (X & ~(2^n-1)) == 0.
    if (!C->getValue().isPowerOf2())
      return false;
    Y = ConstantInt::get(I->getContext(), -C->getValue());
    Pred = ICmpInst::ICMP_EQ;
    break;
  case ICmpInst::ICMP_UGT:
    // X >u 2^n-1 is equivalent to (X & ~(2^n-1)) != 0.
    if (!(C->getValue() + 1).isPowerOf2())
      return false;
    Y = ConstantInt::get(I->getContext(), ~C->getValue());
    Pred = ICmpInst::ICMP_NE;
    break;
  }

  X = I->getOperand(0);
  Z = ConstantInt::getNullValue(C->getType());
  return true;
}

//
// Method: runOnModule()
//
// Description:
//  Entry point for this LLVM pass.
//  Find all GEPs, and simplify them.
//
// Inputs:
//  M - A reference to the LLVM module to transform
//
// Outputs:
//  M - The transformed LLVM module.
//
// Return value:
//  true  - The module was modified.
//  false - The module was not modified.
//
bool SimplifyGEP::runOnModule(Module& M) {
  TD = &getAnalysis<TargetData>();
  preprocess(M);
  for (Module::iterator F = M.begin(); F != M.end(); ++F){
    for (Function::iterator B = F->begin(), FE = F->end(); B != FE; ++B) {      
      for (BasicBlock::iterator I = B->begin(), BE = B->end(); I != BE; I++) {
        if(!(isa<GetElementPtrInst>(I)))
          continue;
        GetElementPtrInst *GEP = cast<GetElementPtrInst>(I);
        Value *PtrOp = GEP->getOperand(0);
        Value *StrippedPtr = PtrOp->stripPointerCasts();
        // Check if the GEP base pointer is enclosed in a cast
        if (StrippedPtr != PtrOp) {
          const PointerType *StrippedPtrTy =cast<PointerType>(StrippedPtr->getType());
          bool HasZeroPointerIndex = false;
          if (ConstantInt *C = dyn_cast<ConstantInt>(GEP->getOperand(1)))
            HasZeroPointerIndex = C->isZero();
          // Transform: GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ...
          // into     : GEP [10 x i8]* X, i32 0, ...
          //
          // Likewise, transform: GEP (bitcast i8* X to [0 x i8]*), i32 0, ...
          //           into     : GEP i8* X, ...
          // 
          // This occurs when the program declares an array extern like "int X[];"
          if (HasZeroPointerIndex) {
            const PointerType *CPTy = cast<PointerType>(PtrOp->getType());
            if (const ArrayType *CATy =
                dyn_cast<ArrayType>(CPTy->getElementType())) {
              // GEP (bitcast i8* X to [0 x i8]*), i32 0, ... ?
              if (CATy->getElementType() == StrippedPtrTy->getElementType()) {
                // -> GEP i8* X, ...
                SmallVector<Value*, 8> Idx(GEP->idx_begin()+1, GEP->idx_end());
                GetElementPtrInst *Res =
                  GetElementPtrInst::Create(StrippedPtr, Idx, GEP->getName(), GEP);
                Res->setIsInBounds(GEP->isInBounds());
                GEP->replaceAllUsesWith(Res);
                continue;
              }

              if (const ArrayType *XATy =
                  dyn_cast<ArrayType>(StrippedPtrTy->getElementType())){
                // GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... ?
                if (CATy->getElementType() == XATy->getElementType()) {
                  // -> GEP [10 x i8]* X, i32 0, ...
                  // At this point, we know that the cast source type is a pointer
                  // to an array of the same type as the destination pointer
                  // array.  Because the array type is never stepped over (there
                  // is a leading zero) we can fold the cast into this GEP.
                  GEP->setOperand(0, StrippedPtr);
                  continue;
                }
              }
            }   
          } else if (GEP->getNumOperands() == 2) {
            // Transform things like:
            // %t = getelementptr i32* bitcast ([2 x i32]* %str to i32*), i32 %V
            // into:  %t1 = getelementptr [2 x i32]* %str, i32 0, i32 %V; bitcast
            Type *SrcElTy = StrippedPtrTy->getElementType();
            Type *ResElTy=cast<PointerType>(PtrOp->getType())->getElementType();
            if (TD && SrcElTy->isArrayTy() &&
                TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType()) ==
                TD->getTypeAllocSize(ResElTy)) {
              Value *Idx[2];
              Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP->getContext()));
              Idx[1] = GEP->getOperand(1);
              Value *NewGEP = GetElementPtrInst::Create(StrippedPtr, Idx,
                                                        GEP->getName(), GEP);
              // V and GEP are both pointer types --> BitCast
              GEP->replaceAllUsesWith(new BitCastInst(NewGEP, GEP->getType(), GEP->getName(), GEP));
              continue;
            }

            // Transform things like:
            // getelementptr i8* bitcast ([100 x double]* X to i8*), i32 %tmp
            //   (where tmp = 8*tmp2) into:
            // getelementptr [100 x double]* %arr, i32 0, i32 %tmp2; bitcast

            if (TD && SrcElTy->isArrayTy() && ResElTy->isIntegerTy(8)) {
              uint64_t ArrayEltSize =
                TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType());

              // Check to see if "tmp" is a scale by a multiple of ArrayEltSize.  We
              // allow either a mul, shift, or constant here.
//.........这里部分代码省略.........

//.........这里部分代码省略.........
				++SICount[0];
			}
			Instruction* SI0 = dyn_cast<Instruction>(SI->getOperand(0));
			if(L->contains(SI) && SI0 && SI0->getOpcode() == Instruction::Add){
				next = SI0;
				++SICount[1];
			}

		}
		Assert(SICount[0]==1 && SICount[1]==1, "");
		ind = IndOrNext;
	}else{
		if(isa<PHINode>(IndOrNext)){
			PHINode* PHI = cast<PHINode>(IndOrNext);
			ind = IndOrNext;
			if(castoff(PHI->getIncomingValue(0)) == castoff(PHI->getIncomingValue(1)) && PHI->getParent() != H)
				ind = castoff(PHI->getIncomingValue(0));
			addfirst = false;
		}else if(IndOrNext->getOpcode() == Instruction::Add){
			next = IndOrNext;
			addfirst = true;
		}else{
			Assert(0 ,"unknow how to analysis");
		}

		for(auto I = H->begin();isa<PHINode>(I);++I){
			PHINode* P = cast<PHINode>(I);
			if(ind && P == ind){
				//start = P->getIncomingValueForBlock(L->getLoopPredecessor());
				start = tryFindStart(P, L, startBB);
				next = dyn_cast<Instruction>(P->getIncomingValueForBlock(L->getLoopLatch()));
			}else if(next && P->getIncomingValueForBlock(L->getLoopLatch()) == next){
				//start = P->getIncomingValueForBlock(L->getLoopPredecessor());
				start = tryFindStart(P, L, startBB);
				ind = P;
			}
		}
	}


	Assert(start ,"couldn't find a start value");
	//process complex loops later
	//DEBUG(if(L->getLoopDepth()>1 || !L->getSubLoops().empty()) return NULL);
	DEBUG(errs()<<"start value:"<<*start<<"\n");
	DEBUG(errs()<<"ind   value:"<<*ind<<"\n");
	DEBUG(errs()<<"next  value:"<<*next<<"\n");


	//process non add later
	unsigned next_phi_idx = 0;
	ConstantInt* Step = NULL,*PrevStep = NULL;/*only used if next is phi node*/
   ret_null_fail(next, "");
	PHINode* next_phi = dyn_cast<PHINode>(next);
	do{
		if(next_phi) {
			next = dyn_cast<Instruction>(next_phi->getIncomingValue(next_phi_idx));
			ret_null_fail(next, "");
			DEBUG(errs()<<"next phi "<<next_phi_idx<<":"<<*next<<"\n");
			if(Step&&PrevStep){
				Assert(Step->getSExtValue() == PrevStep->getSExtValue(),"");
			}
			PrevStep = Step;
		}
		Assert(next->getOpcode() == Instruction::Add , "why induction increment is not Add");
		Assert(next->getOperand(0) == ind ,"why induction increment is not add it self");
		Step = dyn_cast<ConstantInt>(next->getOperand(1));
		Assert(Step,"");
	}while(next_phi && ++next_phi_idx<next_phi->getNumIncomingValues());
	//RET_ON_FAIL(Step->equalsInt(1));
	//assert(VERBOSE(Step->equalsInt(1),Step) && "why induction increment number is not 1");


	Value* RES = NULL;
	//if there are no predecessor, we can insert code into start value basicblock
	IRBuilder<> Builder(InsertPos);
	Assert(start->getType()->isIntegerTy() && END->getType()->isIntegerTy() , " why increment is not integer type");
	if(start->getType() != END->getType()){
		start = Builder.CreateCast(CastInst::getCastOpcode(start, false,
					END->getType(), false),start,END->getType());
	}
   if(Step->getType() != END->getType()){
      //Because Step is a Constant, so it casted is constant
		Step = dyn_cast<ConstantInt>(Builder.CreateCast(CastInst::getCastOpcode(Step, false,
					END->getType(), false),Step,END->getType()));
      AssertRuntime(Step);
   }
	if(Step->isMinusOne())
		RES = Builder.CreateSub(start,END);
	else//Step Couldn't be zero
		RES = Builder.CreateSub(END, start);
	if(addfirst) OneStep -= 1;
	if(Step->isMinusOne()) OneStep*=-1;
	assert(OneStep<=1 && OneStep>=-1);
	RES = (OneStep==1)?Builder.CreateAdd(RES,Step):(OneStep==-1)?Builder.CreateSub(RES, Step):RES;
	if(!Step->isMinusOne()&&!Step->isOne())
		RES = Builder.CreateSDiv(RES, Step);
	RES->setName(H->getName()+".tc");

	return RES;
}

bool InductionDescriptor::isInductionPHI(
    PHINode *Phi, const Loop *TheLoop, ScalarEvolution *SE,
    InductionDescriptor &D, const SCEV *Expr,
    SmallVectorImpl<Instruction *> *CastsToIgnore) {
  Type *PhiTy = Phi->getType();
  // We only handle integer and pointer inductions variables.
  if (!PhiTy->isIntegerTy() && !PhiTy->isPointerTy())
    return false;

  // Check that the PHI is consecutive.
  const SCEV *PhiScev = Expr ? Expr : SE->getSCEV(Phi);
  const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PhiScev);

  if (!AR) {
    LLVM_DEBUG(dbgs() << "LV: PHI is not a poly recurrence.\n");
    return false;
  }

  if (AR->getLoop() != TheLoop) {
    // FIXME: We should treat this as a uniform. Unfortunately, we
    // don't currently know how to handled uniform PHIs.
    LLVM_DEBUG(
        dbgs() << "LV: PHI is a recurrence with respect to an outer loop.\n");
    return false;
  }

  Value *StartValue =
      Phi->getIncomingValueForBlock(AR->getLoop()->getLoopPreheader());

  BasicBlock *Latch = AR->getLoop()->getLoopLatch();
  if (!Latch)
    return false;
  BinaryOperator *BOp =
      dyn_cast<BinaryOperator>(Phi->getIncomingValueForBlock(Latch));

  const SCEV *Step = AR->getStepRecurrence(*SE);
  // Calculate the pointer stride and check if it is consecutive.
  // The stride may be a constant or a loop invariant integer value.
  const SCEVConstant *ConstStep = dyn_cast<SCEVConstant>(Step);
  if (!ConstStep && !SE->isLoopInvariant(Step, TheLoop))
    return false;

  if (PhiTy->isIntegerTy()) {
    D = InductionDescriptor(StartValue, IK_IntInduction, Step, BOp,
                            CastsToIgnore);
    return true;
  }

  assert(PhiTy->isPointerTy() && "The PHI must be a pointer");
  // Pointer induction should be a constant.
  if (!ConstStep)
    return false;

  ConstantInt *CV = ConstStep->getValue();
  Type *PointerElementType = PhiTy->getPointerElementType();
  // The pointer stride cannot be determined if the pointer element type is not
  // sized.
  if (!PointerElementType->isSized())
    return false;

  const DataLayout &DL = Phi->getModule()->getDataLayout();
  int64_t Size = static_cast<int64_t>(DL.getTypeAllocSize(PointerElementType));
  if (!Size)
    return false;

  int64_t CVSize = CV->getSExtValue();
  if (CVSize % Size)
    return false;
  auto *StepValue =
      SE->getConstant(CV->getType(), CVSize / Size, true /* signed */);
  D = InductionDescriptor(StartValue, IK_PtrInduction, StepValue, BOp);
  return true;
}