示例#1
0
unsigned FastISel::getRegForGEPIndex(Value *Idx) {
  unsigned IdxN = getRegForValue(Idx);
  if (IdxN == 0)
    // Unhandled operand. Halt "fast" selection and bail.
    return 0;

  // If the index is smaller or larger than intptr_t, truncate or extend it.
  MVT PtrVT = TLI.getPointerTy();
  EVT IdxVT = EVT::getEVT(Idx->getType(), /*HandleUnknown=*/false);
  if (IdxVT.bitsLT(PtrVT))
    IdxN = FastEmit_r(IdxVT.getSimpleVT(), PtrVT, ISD::SIGN_EXTEND, IdxN);
  else if (IdxVT.bitsGT(PtrVT))
    IdxN = FastEmit_r(IdxVT.getSimpleVT(), PtrVT, ISD::TRUNCATE, IdxN);
  return IdxN;
}
示例#2
0
/// Get the EVTs and ArgFlags collections that represent the legalized return
/// type of the given function.  This does not require a DAG or a return value,
/// and is suitable for use before any DAGs for the function are constructed.
/// TODO: Move this out of TargetLowering.cpp.
void llvm::GetReturnInfo(Type* ReturnType, AttributeSet attr,
                         SmallVectorImpl<ISD::OutputArg> &Outs,
                         const TargetLowering &TLI) {
  SmallVector<EVT, 4> ValueVTs;
  ComputeValueVTs(TLI, ReturnType, ValueVTs);
  unsigned NumValues = ValueVTs.size();
  if (NumValues == 0) return;

  for (unsigned j = 0, f = NumValues; j != f; ++j) {
    EVT VT = ValueVTs[j];
    ISD::NodeType ExtendKind = ISD::ANY_EXTEND;

    if (attr.hasAttribute(AttributeSet::ReturnIndex, Attribute::SExt))
      ExtendKind = ISD::SIGN_EXTEND;
    else if (attr.hasAttribute(AttributeSet::ReturnIndex, Attribute::ZExt))
      ExtendKind = ISD::ZERO_EXTEND;

    // FIXME: C calling convention requires the return type to be promoted to
    // at least 32-bit. But this is not necessary for non-C calling
    // conventions. The frontend should mark functions whose return values
    // require promoting with signext or zeroext attributes.
    if (ExtendKind != ISD::ANY_EXTEND && VT.isInteger()) {
      MVT MinVT = TLI.getRegisterType(ReturnType->getContext(), MVT::i32);
      if (VT.bitsLT(MinVT))
        VT = MinVT;
    }

    unsigned NumParts = TLI.getNumRegisters(ReturnType->getContext(), VT);
    MVT PartVT = TLI.getRegisterType(ReturnType->getContext(), VT);

    // 'inreg' on function refers to return value
    ISD::ArgFlagsTy Flags = ISD::ArgFlagsTy();
    if (attr.hasAttribute(AttributeSet::ReturnIndex, Attribute::InReg))
      Flags.setInReg();

    // Propagate extension type if any
    if (attr.hasAttribute(AttributeSet::ReturnIndex, Attribute::SExt))
      Flags.setSExt();
    else if (attr.hasAttribute(AttributeSet::ReturnIndex, Attribute::ZExt))
      Flags.setZExt();

    for (unsigned i = 0; i < NumParts; ++i)
      Outs.push_back(ISD::OutputArg(Flags, PartVT, /*isFixed=*/true, 0, 0));
  }
}
void DAGTypeLegalizer::ExpandRes_EXTRACT_VECTOR_ELT(SDNode *N, SDValue &Lo,
                                                    SDValue &Hi) {
  SDValue OldVec = N->getOperand(0);
  unsigned OldElts = OldVec.getValueType().getVectorNumElements();
  EVT OldEltVT = OldVec.getValueType().getVectorElementType();
  SDLoc dl(N);

  // Convert to a vector of the expanded element type, for example
  // <3 x i64> -> <6 x i32>.
  EVT OldVT = N->getValueType(0);
  EVT NewVT = TLI.getTypeToTransformTo(*DAG.getContext(), OldVT);

  if (OldVT != OldEltVT) {
    // The result of EXTRACT_VECTOR_ELT may be larger than the element type of
    // the input vector.  If so, extend the elements of the input vector to the
    // same bitwidth as the result before expanding.
    assert(OldEltVT.bitsLT(OldVT) && "Result type smaller then element type!");
    EVT NVecVT = EVT::getVectorVT(*DAG.getContext(), OldVT, OldElts);
    OldVec = DAG.getNode(ISD::ANY_EXTEND, dl, NVecVT, N->getOperand(0));
  }

  SDValue NewVec = DAG.getNode(ISD::BITCAST, dl,
                               EVT::getVectorVT(*DAG.getContext(),
                                                NewVT, 2*OldElts),
                               OldVec);

  // Extract the elements at 2 * Idx and 2 * Idx + 1 from the new vector.
  SDValue Idx = N->getOperand(1);

  // Make sure the type of Idx is big enough to hold the new values.
  if (Idx.getValueType().bitsLT(TLI.getPointerTy()))
    Idx = DAG.getNode(ISD::ZERO_EXTEND, dl, TLI.getPointerTy(), Idx);

  Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx, Idx);
  Lo = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NewVT, NewVec, Idx);

  Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx,
                    DAG.getConstant(1, Idx.getValueType()));
  Hi = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NewVT, NewVec, Idx);

  if (TLI.isBigEndian())
    std::swap(Lo, Hi);
}
示例#4
0
std::pair<unsigned, bool> FastISel::getRegForGEPIndex(const Value *Idx) {
  unsigned IdxN = getRegForValue(Idx);
  if (IdxN == 0)
    // Unhandled operand. Halt "fast" selection and bail.
    return std::pair<unsigned, bool>(0, false);

  bool IdxNIsKill = hasTrivialKill(Idx);

  // If the index is smaller or larger than intptr_t, truncate or extend it.
  MVT PtrVT = TLI.getPointerTy();
  EVT IdxVT = EVT::getEVT(Idx->getType(), /*HandleUnknown=*/false);
  if (IdxVT.bitsLT(PtrVT)) {
    IdxN = FastEmit_r(IdxVT.getSimpleVT(), PtrVT, ISD::SIGN_EXTEND,
                      IdxN, IdxNIsKill);
    IdxNIsKill = true;
  }
  else if (IdxVT.bitsGT(PtrVT)) {
    IdxN = FastEmit_r(IdxVT.getSimpleVT(), PtrVT, ISD::TRUNCATE,
                      IdxN, IdxNIsKill);
    IdxNIsKill = true;
  }
  return std::pair<unsigned, bool>(IdxN, IdxNIsKill);
}
示例#5
0
/// OptimizeNoopCopyExpression - If the specified cast instruction is a noop
/// copy (e.g. it's casting from one pointer type to another, i32->i8 on PPC),
/// sink it into user blocks to reduce the number of virtual
/// registers that must be created and coalesced.
///
/// Return true if any changes are made.
///
static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI) {
    // If this is a noop copy,
    EVT SrcVT = TLI.getValueType(CI->getOperand(0)->getType());
    EVT DstVT = TLI.getValueType(CI->getType());

    // This is an fp<->int conversion?
    if (SrcVT.isInteger() != DstVT.isInteger())
        return false;

    // If this is an extension, it will be a zero or sign extension, which
    // isn't a noop.
    if (SrcVT.bitsLT(DstVT)) return false;

    // If these values will be promoted, find out what they will be promoted
    // to.  This helps us consider truncates on PPC as noop copies when they
    // are.
    if (TLI.getTypeAction(CI->getContext(), SrcVT) ==
            TargetLowering::TypePromoteInteger)
        SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT);
    if (TLI.getTypeAction(CI->getContext(), DstVT) ==
            TargetLowering::TypePromoteInteger)
        DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT);

    // If, after promotion, these are the same types, this is a noop copy.
    if (SrcVT != DstVT)
        return false;

    BasicBlock *DefBB = CI->getParent();

    /// InsertedCasts - Only insert a cast in each block once.
    DenseMap<BasicBlock*, CastInst*> InsertedCasts;

    bool MadeChange = false;
    for (Value::use_iterator UI = CI->use_begin(), E = CI->use_end();
            UI != E; ) {
        Use &TheUse = UI.getUse();
        Instruction *User = cast<Instruction>(*UI);

        // Figure out which BB this cast is used in.  For PHI's this is the
        // appropriate predecessor block.
        BasicBlock *UserBB = User->getParent();
        if (PHINode *PN = dyn_cast<PHINode>(User)) {
            UserBB = PN->getIncomingBlock(UI);
        }

        // Preincrement use iterator so we don't invalidate it.
        ++UI;

        // If this user is in the same block as the cast, don't change the cast.
        if (UserBB == DefBB) continue;

        // If we have already inserted a cast into this block, use it.
        CastInst *&InsertedCast = InsertedCasts[UserBB];

        if (!InsertedCast) {
            BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
            InsertedCast =
                CastInst::Create(CI->getOpcode(), CI->getOperand(0), CI->getType(), "",
                                 InsertPt);
            MadeChange = true;
        }

        // Replace a use of the cast with a use of the new cast.
        TheUse = InsertedCast;
        ++NumCastUses;
    }

    // If we removed all uses, nuke the cast.
    if (CI->use_empty()) {
        CI->eraseFromParent();
        MadeChange = true;
    }

    return MadeChange;
}
示例#6
0
bool
FastISel::SelectOperator(const User *I, unsigned Opcode) {
  switch (Opcode) {
  case Instruction::Add:
    return SelectBinaryOp(I, ISD::ADD);
  case Instruction::FAdd:
    return SelectBinaryOp(I, ISD::FADD);
  case Instruction::Sub:
    return SelectBinaryOp(I, ISD::SUB);
  case Instruction::FSub:
    // FNeg is currently represented in LLVM IR as a special case of FSub.
    if (BinaryOperator::isFNeg(I))
      return SelectFNeg(I);
    return SelectBinaryOp(I, ISD::FSUB);
  case Instruction::Mul:
    return SelectBinaryOp(I, ISD::MUL);
  case Instruction::FMul:
    return SelectBinaryOp(I, ISD::FMUL);
  case Instruction::SDiv:
    return SelectBinaryOp(I, ISD::SDIV);
  case Instruction::UDiv:
    return SelectBinaryOp(I, ISD::UDIV);
  case Instruction::FDiv:
    return SelectBinaryOp(I, ISD::FDIV);
  case Instruction::SRem:
    return SelectBinaryOp(I, ISD::SREM);
  case Instruction::URem:
    return SelectBinaryOp(I, ISD::UREM);
  case Instruction::FRem:
    return SelectBinaryOp(I, ISD::FREM);
  case Instruction::Shl:
    return SelectBinaryOp(I, ISD::SHL);
  case Instruction::LShr:
    return SelectBinaryOp(I, ISD::SRL);
  case Instruction::AShr:
    return SelectBinaryOp(I, ISD::SRA);
  case Instruction::And:
    return SelectBinaryOp(I, ISD::AND);
  case Instruction::Or:
    return SelectBinaryOp(I, ISD::OR);
  case Instruction::Xor:
    return SelectBinaryOp(I, ISD::XOR);

  case Instruction::GetElementPtr:
    return SelectGetElementPtr(I);

  case Instruction::Br: {
    const BranchInst *BI = cast<BranchInst>(I);

    if (BI->isUnconditional()) {
      const BasicBlock *LLVMSucc = BI->getSuccessor(0);
      MachineBasicBlock *MSucc = FuncInfo.MBBMap[LLVMSucc];
      FastEmitBranch(MSucc, BI->getDebugLoc());
      return true;
    }

    // Conditional branches are not handed yet.
    // Halt "fast" selection and bail.
    return false;
  }

  case Instruction::Unreachable:
    // Nothing to emit.
    return true;

  case Instruction::Alloca:
    // FunctionLowering has the static-sized case covered.
    if (FuncInfo.StaticAllocaMap.count(cast<AllocaInst>(I)))
      return true;

    // Dynamic-sized alloca is not handled yet.
    return false;

  case Instruction::Call:
    return SelectCall(I);

  case Instruction::BitCast:
    return SelectBitCast(I);

  case Instruction::FPToSI:
    return SelectCast(I, ISD::FP_TO_SINT);
  case Instruction::ZExt:
    return SelectCast(I, ISD::ZERO_EXTEND);
  case Instruction::SExt:
    return SelectCast(I, ISD::SIGN_EXTEND);
  case Instruction::Trunc:
    return SelectCast(I, ISD::TRUNCATE);
  case Instruction::SIToFP:
    return SelectCast(I, ISD::SINT_TO_FP);

  case Instruction::IntToPtr: // Deliberate fall-through.
  case Instruction::PtrToInt: {
    EVT SrcVT = TLI.getValueType(I->getOperand(0)->getType());
    EVT DstVT = TLI.getValueType(I->getType());
    if (DstVT.bitsGT(SrcVT))
      return SelectCast(I, ISD::ZERO_EXTEND);
    if (DstVT.bitsLT(SrcVT))
      return SelectCast(I, ISD::TRUNCATE);
    unsigned Reg = getRegForValue(I->getOperand(0));
    if (Reg == 0) return false;
    UpdateValueMap(I, Reg);
    return true;
  }

  case Instruction::PHI:
    llvm_unreachable("FastISel shouldn't visit PHI nodes!");

  default:
    // Unhandled instruction. Halt "fast" selection and bail.
    return false;
  }
}
示例#7
0
bool FastISel::SelectCall(const User *I) {
  const Function *F = cast<CallInst>(I)->getCalledFunction();
  if (!F) return false;

  // Handle selected intrinsic function calls.
  unsigned IID = F->getIntrinsicID();
  switch (IID) {
  default: break;
  case Intrinsic::dbg_declare: {
    const DbgDeclareInst *DI = cast<DbgDeclareInst>(I);
    if (!DIVariable(DI->getVariable()).Verify() ||
        !FuncInfo.MF->getMMI().hasDebugInfo())
      return true;

    const Value *Address = DI->getAddress();
    if (!Address || isa<UndefValue>(Address) || isa<AllocaInst>(Address))
      return true;

    unsigned Reg = 0;
    unsigned Offset = 0;
    if (const Argument *Arg = dyn_cast<Argument>(Address)) {
      if (Arg->hasByValAttr()) {
        // Byval arguments' frame index is recorded during argument lowering.
        // Use this info directly.
        Offset = FuncInfo.getByValArgumentFrameIndex(Arg);
        if (Offset)
          Reg = TRI.getFrameRegister(*FuncInfo.MF);
      }
    }
    if (!Reg)
      Reg = getRegForValue(Address);

    if (Reg)
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
              TII.get(TargetOpcode::DBG_VALUE))
        .addReg(Reg, RegState::Debug).addImm(Offset)
        .addMetadata(DI->getVariable());
    return true;
  }
  case Intrinsic::dbg_value: {
    // This form of DBG_VALUE is target-independent.
    const DbgValueInst *DI = cast<DbgValueInst>(I);
    const TargetInstrDesc &II = TII.get(TargetOpcode::DBG_VALUE);
    const Value *V = DI->getValue();
    if (!V) {
      // Currently the optimizer can produce this; insert an undef to
      // help debugging.  Probably the optimizer should not do this.
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
        .addReg(0U).addImm(DI->getOffset())
        .addMetadata(DI->getVariable());
    } else if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
        .addImm(CI->getZExtValue()).addImm(DI->getOffset())
        .addMetadata(DI->getVariable());
    } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
        .addFPImm(CF).addImm(DI->getOffset())
        .addMetadata(DI->getVariable());
    } else if (unsigned Reg = lookUpRegForValue(V)) {
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
        .addReg(Reg, RegState::Debug).addImm(DI->getOffset())
        .addMetadata(DI->getVariable());
    } else {
      // We can't yet handle anything else here because it would require
      // generating code, thus altering codegen because of debug info.
      DEBUG(dbgs() << "Dropping debug info for " << DI);
    }
    return true;
  }
  case Intrinsic::eh_exception: {
    EVT VT = TLI.getValueType(I->getType());
    switch (TLI.getOperationAction(ISD::EXCEPTIONADDR, VT)) {
    default: break;
    case TargetLowering::Expand: {
      assert(FuncInfo.MBB->isLandingPad() &&
             "Call to eh.exception not in landing pad!");
      unsigned Reg = TLI.getExceptionAddressRegister();
      const TargetRegisterClass *RC = TLI.getRegClassFor(VT);
      unsigned ResultReg = createResultReg(RC);
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
              ResultReg).addReg(Reg);
      UpdateValueMap(I, ResultReg);
      return true;
    }
    }
    break;
  }
  case Intrinsic::eh_selector: {
    EVT VT = TLI.getValueType(I->getType());
    switch (TLI.getOperationAction(ISD::EHSELECTION, VT)) {
    default: break;
    case TargetLowering::Expand: {
      if (FuncInfo.MBB->isLandingPad())
        AddCatchInfo(*cast<CallInst>(I), &FuncInfo.MF->getMMI(), FuncInfo.MBB);
      else {
#ifndef NDEBUG
        FuncInfo.CatchInfoLost.insert(cast<CallInst>(I));
#endif
        // FIXME: Mark exception selector register as live in.  Hack for PR1508.
        unsigned Reg = TLI.getExceptionSelectorRegister();
        if (Reg) FuncInfo.MBB->addLiveIn(Reg);
      }

      unsigned Reg = TLI.getExceptionSelectorRegister();
      EVT SrcVT = TLI.getPointerTy();
      const TargetRegisterClass *RC = TLI.getRegClassFor(SrcVT);
      unsigned ResultReg = createResultReg(RC);
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
              ResultReg).addReg(Reg);

      bool ResultRegIsKill = hasTrivialKill(I);

      // Cast the register to the type of the selector.
      if (SrcVT.bitsGT(MVT::i32))
        ResultReg = FastEmit_r(SrcVT.getSimpleVT(), MVT::i32, ISD::TRUNCATE,
                               ResultReg, ResultRegIsKill);
      else if (SrcVT.bitsLT(MVT::i32))
        ResultReg = FastEmit_r(SrcVT.getSimpleVT(), MVT::i32,
                               ISD::SIGN_EXTEND, ResultReg, ResultRegIsKill);
      if (ResultReg == 0)
        // Unhandled operand. Halt "fast" selection and bail.
        return false;

      UpdateValueMap(I, ResultReg);

      return true;
    }
    }
    break;
  }
  }

  // An arbitrary call. Bail.
  return false;
}
示例#8
0
bool FastISel::SelectCall(User *I) {
  Function *F = cast<CallInst>(I)->getCalledFunction();
  if (!F) return false;

  unsigned IID = F->getIntrinsicID();
  switch (IID) {
  default: break;
  case Intrinsic::dbg_stoppoint: 
  case Intrinsic::dbg_region_start: 
  case Intrinsic::dbg_region_end: 
  case Intrinsic::dbg_func_start:
    // FIXME - Remove this instructions once the dust settles.
    return true;
  case Intrinsic::dbg_declare: {
    DbgDeclareInst *DI = cast<DbgDeclareInst>(I);
    if (!isValidDebugInfoIntrinsic(*DI, CodeGenOpt::None) || !DW
        || !DW->ShouldEmitDwarfDebug())
      return true;

    Value *Address = DI->getAddress();
    if (BitCastInst *BCI = dyn_cast<BitCastInst>(Address))
      Address = BCI->getOperand(0);
    AllocaInst *AI = dyn_cast<AllocaInst>(Address);
    // Don't handle byval struct arguments or VLAs, for example.
    if (!AI) break;
    DenseMap<const AllocaInst*, int>::iterator SI =
      StaticAllocaMap.find(AI);
    if (SI == StaticAllocaMap.end()) break; // VLAs.
    int FI = SI->second;
    if (MMI) {
      MetadataContext &TheMetadata = 
        DI->getParent()->getContext().getMetadata();
      unsigned MDDbgKind = TheMetadata.getMDKind("dbg");
      MDNode *Dbg = TheMetadata.getMD(MDDbgKind, DI);
      MMI->setVariableDbgInfo(DI->getVariable(), FI, Dbg);
    }
    return true;
  }
  case Intrinsic::eh_exception: {
    EVT VT = TLI.getValueType(I->getType());
    switch (TLI.getOperationAction(ISD::EXCEPTIONADDR, VT)) {
    default: break;
    case TargetLowering::Expand: {
      assert(MBB->isLandingPad() && "Call to eh.exception not in landing pad!");
      unsigned Reg = TLI.getExceptionAddressRegister();
      const TargetRegisterClass *RC = TLI.getRegClassFor(VT);
      unsigned ResultReg = createResultReg(RC);
      bool InsertedCopy = TII.copyRegToReg(*MBB, MBB->end(), ResultReg,
                                           Reg, RC, RC);
      assert(InsertedCopy && "Can't copy address registers!");
      InsertedCopy = InsertedCopy;
      UpdateValueMap(I, ResultReg);
      return true;
    }
    }
    break;
  }
  case Intrinsic::eh_selector: {
    EVT VT = TLI.getValueType(I->getType());
    switch (TLI.getOperationAction(ISD::EHSELECTION, VT)) {
    default: break;
    case TargetLowering::Expand: {
      if (MMI) {
        if (MBB->isLandingPad())
          AddCatchInfo(*cast<CallInst>(I), MMI, MBB);
        else {
#ifndef NDEBUG
          CatchInfoLost.insert(cast<CallInst>(I));
#endif
          // FIXME: Mark exception selector register as live in.  Hack for PR1508.
          unsigned Reg = TLI.getExceptionSelectorRegister();
          if (Reg) MBB->addLiveIn(Reg);
        }

        unsigned Reg = TLI.getExceptionSelectorRegister();
        EVT SrcVT = TLI.getPointerTy();
        const TargetRegisterClass *RC = TLI.getRegClassFor(SrcVT);
        unsigned ResultReg = createResultReg(RC);
        bool InsertedCopy = TII.copyRegToReg(*MBB, MBB->end(), ResultReg, Reg,
                                             RC, RC);
        assert(InsertedCopy && "Can't copy address registers!");
        InsertedCopy = InsertedCopy;

        // Cast the register to the type of the selector.
        if (SrcVT.bitsGT(MVT::i32))
          ResultReg = FastEmit_r(SrcVT.getSimpleVT(), MVT::i32, ISD::TRUNCATE,
                                 ResultReg);
        else if (SrcVT.bitsLT(MVT::i32))
          ResultReg = FastEmit_r(SrcVT.getSimpleVT(), MVT::i32,
                                 ISD::SIGN_EXTEND, ResultReg);
        if (ResultReg == 0)
          // Unhandled operand. Halt "fast" selection and bail.
          return false;

        UpdateValueMap(I, ResultReg);
      } else {
        unsigned ResultReg =
          getRegForValue(Constant::getNullValue(I->getType()));
        UpdateValueMap(I, ResultReg);
      }
      return true;
    }
    }
    break;
  }
  }
  return false;
}
示例#9
0
bool FastISel::SelectCall(const User *I) {
  const Function *F = cast<CallInst>(I)->getCalledFunction();
  if (!F) return false;

  // Handle selected intrinsic function calls.
  unsigned IID = F->getIntrinsicID();
  switch (IID) {
  default: break;
  case Intrinsic::dbg_declare: {
    const DbgDeclareInst *DI = cast<DbgDeclareInst>(I);
    if (!DIDescriptor::ValidDebugInfo(DI->getVariable(), CodeGenOpt::None) ||
        !MF.getMMI().hasDebugInfo())
      return true;

    const Value *Address = DI->getAddress();
    if (!Address)
      return true;
    if (isa<UndefValue>(Address))
      return true;
    const AllocaInst *AI = dyn_cast<AllocaInst>(Address);
    // Don't handle byval struct arguments or VLAs, for example.
    if (!AI) break;
    DenseMap<const AllocaInst*, int>::iterator SI =
      StaticAllocaMap.find(AI);
    if (SI == StaticAllocaMap.end()) break; // VLAs.
    int FI = SI->second;
    if (!DI->getDebugLoc().isUnknown())
      MF.getMMI().setVariableDbgInfo(DI->getVariable(), FI, DI->getDebugLoc());
    
    // Building the map above is target independent.  Generating DBG_VALUE
    // inline is target dependent; do this now.
    (void)TargetSelectInstruction(cast<Instruction>(I));
    return true;
  }
  case Intrinsic::dbg_value: {
    // This form of DBG_VALUE is target-independent.
    const DbgValueInst *DI = cast<DbgValueInst>(I);
    const TargetInstrDesc &II = TII.get(TargetOpcode::DBG_VALUE);
    const Value *V = DI->getValue();
    if (!V) {
      // Currently the optimizer can produce this; insert an undef to
      // help debugging.  Probably the optimizer should not do this.
      BuildMI(MBB, DL, II).addReg(0U).addImm(DI->getOffset()).
                                     addMetadata(DI->getVariable());
    } else if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
      BuildMI(MBB, DL, II).addImm(CI->getZExtValue()).addImm(DI->getOffset()).
                                     addMetadata(DI->getVariable());
    } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
      BuildMI(MBB, DL, II).addFPImm(CF).addImm(DI->getOffset()).
                                     addMetadata(DI->getVariable());
    } else if (unsigned Reg = lookUpRegForValue(V)) {
      BuildMI(MBB, DL, II).addReg(Reg, RegState::Debug).addImm(DI->getOffset()).
                                     addMetadata(DI->getVariable());
    } else {
      // We can't yet handle anything else here because it would require
      // generating code, thus altering codegen because of debug info.
      // Insert an undef so we can see what we dropped.
      BuildMI(MBB, DL, II).addReg(0U).addImm(DI->getOffset()).
                                     addMetadata(DI->getVariable());
    }     
    return true;
  }
  case Intrinsic::eh_exception: {
    EVT VT = TLI.getValueType(I->getType());
    switch (TLI.getOperationAction(ISD::EXCEPTIONADDR, VT)) {
    default: break;
    case TargetLowering::Expand: {
      assert(MBB->isLandingPad() && "Call to eh.exception not in landing pad!");
      unsigned Reg = TLI.getExceptionAddressRegister();
      const TargetRegisterClass *RC = TLI.getRegClassFor(VT);
      unsigned ResultReg = createResultReg(RC);
      bool InsertedCopy = TII.copyRegToReg(*MBB, MBB->end(), ResultReg,
                                           Reg, RC, RC);
      assert(InsertedCopy && "Can't copy address registers!");
      InsertedCopy = InsertedCopy;
      UpdateValueMap(I, ResultReg);
      return true;
    }
    }
    break;
  }
  case Intrinsic::eh_selector: {
    EVT VT = TLI.getValueType(I->getType());
    switch (TLI.getOperationAction(ISD::EHSELECTION, VT)) {
    default: break;
    case TargetLowering::Expand: {
      if (MBB->isLandingPad())
        AddCatchInfo(*cast<CallInst>(I), &MF.getMMI(), MBB);
      else {
#ifndef NDEBUG
        CatchInfoLost.insert(cast<CallInst>(I));
#endif
        // FIXME: Mark exception selector register as live in.  Hack for PR1508.
        unsigned Reg = TLI.getExceptionSelectorRegister();
        if (Reg) MBB->addLiveIn(Reg);
      }

      unsigned Reg = TLI.getExceptionSelectorRegister();
      EVT SrcVT = TLI.getPointerTy();
      const TargetRegisterClass *RC = TLI.getRegClassFor(SrcVT);
      unsigned ResultReg = createResultReg(RC);
      bool InsertedCopy = TII.copyRegToReg(*MBB, MBB->end(), ResultReg, Reg,
                                           RC, RC);
      assert(InsertedCopy && "Can't copy address registers!");
      InsertedCopy = InsertedCopy;

      // Cast the register to the type of the selector.
      if (SrcVT.bitsGT(MVT::i32))
        ResultReg = FastEmit_r(SrcVT.getSimpleVT(), MVT::i32, ISD::TRUNCATE,
                               ResultReg);
      else if (SrcVT.bitsLT(MVT::i32))
        ResultReg = FastEmit_r(SrcVT.getSimpleVT(), MVT::i32,
                               ISD::SIGN_EXTEND, ResultReg);
      if (ResultReg == 0)
        // Unhandled operand. Halt "fast" selection and bail.
        return false;

      UpdateValueMap(I, ResultReg);

      return true;
    }
    }
    break;
  }
  }

  // An arbitrary call. Bail.
  return false;
}