Use 2-byte alignment for functions. 4 bytes are clear overkill here.
[oota-llvm.git] / lib / Target / MSP430 / MSP430ISelLowering.cpp
index 99996bbb8487ceaf371ab1379f1e7d7f4cc7aae1..adc6d58961ee378ea6f9fefdc9534173b39fcdf4 100644 (file)
 #include "llvm/CodeGen/PseudoSourceValue.h"
 #include "llvm/CodeGen/SelectionDAGISel.h"
 #include "llvm/CodeGen/ValueTypes.h"
+#include "llvm/Target/TargetLoweringObjectFile.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/ADT/VectorExtras.h"
 using namespace llvm;
 
 MSP430TargetLowering::MSP430TargetLowering(MSP430TargetMachine &tm) :
-  TargetLowering(tm), Subtarget(*tm.getSubtargetImpl()), TM(tm) {
+  TargetLowering(tm, new TargetLoweringObjectFileELF()),
+  Subtarget(*tm.getSubtargetImpl()), TM(tm) {
 
   // Set up the register classes.
-  addRegisterClass(MVT::i16, MSP430::MSP430RegsRegisterClass);
+  addRegisterClass(MVT::i8,  MSP430::GR8RegisterClass);
+  addRegisterClass(MVT::i16, MSP430::GR16RegisterClass);
 
   // Compute derived properties from the register classes
   computeRegisterProperties();
+
+  // Provide all sorts of operation actions
+
+  // Division is expensive
+  setIntDivIsCheap(false);
+
+  // Even if we have only 1 bit shift here, we can perform
+  // shifts of the whole bitwidth 1 bit per step.
+  setShiftAmountType(MVT::i8);
+
+  setStackPointerRegisterToSaveRestore(MSP430::SPW);
+  setBooleanContents(ZeroOrOneBooleanContent);
+  setSchedulingPreference(SchedulingForLatency);
+
+  // We have post-incremented loads / stores.
+  setIndexedLoadAction(ISD::POST_INC, MVT::i8, Legal);
+  setIndexedLoadAction(ISD::POST_INC, MVT::i16, Legal);
+
+  setLoadExtAction(ISD::EXTLOAD,  MVT::i1,  Promote);
+  setLoadExtAction(ISD::SEXTLOAD, MVT::i1,  Promote);
+  setLoadExtAction(ISD::ZEXTLOAD, MVT::i1,  Promote);
+  setLoadExtAction(ISD::SEXTLOAD, MVT::i8,  Expand);
+  setLoadExtAction(ISD::SEXTLOAD, MVT::i16, Expand);
+
+  // We don't have any truncstores
+  setTruncStoreAction(MVT::i16, MVT::i8, Expand);
+
+  setOperationAction(ISD::SRA,              MVT::i8,    Custom);
+  setOperationAction(ISD::SHL,              MVT::i8,    Custom);
+  setOperationAction(ISD::SRL,              MVT::i8,    Custom);
+  setOperationAction(ISD::SRA,              MVT::i16,   Custom);
+  setOperationAction(ISD::SHL,              MVT::i16,   Custom);
+  setOperationAction(ISD::SRL,              MVT::i16,   Custom);
+  setOperationAction(ISD::ROTL,             MVT::i8,    Expand);
+  setOperationAction(ISD::ROTR,             MVT::i8,    Expand);
+  setOperationAction(ISD::ROTL,             MVT::i16,   Expand);
+  setOperationAction(ISD::ROTR,             MVT::i16,   Expand);
+  setOperationAction(ISD::GlobalAddress,    MVT::i16,   Custom);
+  setOperationAction(ISD::ExternalSymbol,   MVT::i16,   Custom);
+  setOperationAction(ISD::BR_JT,            MVT::Other, Expand);
+  setOperationAction(ISD::BRIND,            MVT::Other, Expand);
+  setOperationAction(ISD::BR_CC,            MVT::i8,    Custom);
+  setOperationAction(ISD::BR_CC,            MVT::i16,   Custom);
+  setOperationAction(ISD::BRCOND,           MVT::Other, Expand);
+  setOperationAction(ISD::SETCC,            MVT::i8,    Expand);
+  setOperationAction(ISD::SETCC,            MVT::i16,   Expand);
+  setOperationAction(ISD::SELECT,           MVT::i8,    Expand);
+  setOperationAction(ISD::SELECT,           MVT::i16,   Expand);
+  setOperationAction(ISD::SELECT_CC,        MVT::i8,    Custom);
+  setOperationAction(ISD::SELECT_CC,        MVT::i16,   Custom);
+  setOperationAction(ISD::SIGN_EXTEND,      MVT::i16,   Custom);
+  setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i8, Expand);
+  setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i16, Expand);
+
+  setOperationAction(ISD::CTTZ,             MVT::i8,    Expand);
+  setOperationAction(ISD::CTTZ,             MVT::i16,   Expand);
+  setOperationAction(ISD::CTLZ,             MVT::i8,    Expand);
+  setOperationAction(ISD::CTLZ,             MVT::i16,   Expand);
+  setOperationAction(ISD::CTPOP,            MVT::i8,    Expand);
+  setOperationAction(ISD::CTPOP,            MVT::i16,   Expand);
+
+  setOperationAction(ISD::SHL_PARTS,        MVT::i8,    Expand);
+  setOperationAction(ISD::SHL_PARTS,        MVT::i16,   Expand);
+  setOperationAction(ISD::SRL_PARTS,        MVT::i8,    Expand);
+  setOperationAction(ISD::SRL_PARTS,        MVT::i16,   Expand);
+  setOperationAction(ISD::SRA_PARTS,        MVT::i8,    Expand);
+  setOperationAction(ISD::SRA_PARTS,        MVT::i16,   Expand);
+
+  setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1,   Expand);
+
+  // FIXME: Implement efficiently multiplication by a constant
+  setOperationAction(ISD::MUL,              MVT::i8,    Expand);
+  setOperationAction(ISD::MULHS,            MVT::i8,    Expand);
+  setOperationAction(ISD::MULHU,            MVT::i8,    Expand);
+  setOperationAction(ISD::SMUL_LOHI,        MVT::i8,    Expand);
+  setOperationAction(ISD::UMUL_LOHI,        MVT::i8,    Expand);
+  setOperationAction(ISD::MUL,              MVT::i16,   Expand);
+  setOperationAction(ISD::MULHS,            MVT::i16,   Expand);
+  setOperationAction(ISD::MULHU,            MVT::i16,   Expand);
+  setOperationAction(ISD::SMUL_LOHI,        MVT::i16,   Expand);
+  setOperationAction(ISD::UMUL_LOHI,        MVT::i16,   Expand);
+
+  setOperationAction(ISD::UDIV,             MVT::i8,    Expand);
+  setOperationAction(ISD::UDIVREM,          MVT::i8,    Expand);
+  setOperationAction(ISD::UREM,             MVT::i8,    Expand);
+  setOperationAction(ISD::SDIV,             MVT::i8,    Expand);
+  setOperationAction(ISD::SDIVREM,          MVT::i8,    Expand);
+  setOperationAction(ISD::SREM,             MVT::i8,    Expand);
+  setOperationAction(ISD::UDIV,             MVT::i16,   Expand);
+  setOperationAction(ISD::UDIVREM,          MVT::i16,   Expand);
+  setOperationAction(ISD::UREM,             MVT::i16,   Expand);
+  setOperationAction(ISD::SDIV,             MVT::i16,   Expand);
+  setOperationAction(ISD::SDIVREM,          MVT::i16,   Expand);
+  setOperationAction(ISD::SREM,             MVT::i16,   Expand);
 }
 
-SDValue MSP430TargetLowering::
-LowerOperation(SDValue Op, SelectionDAG &DAG) {
+SDValue MSP430TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) {
   switch (Op.getOpcode()) {
-  case ISD::FORMAL_ARGUMENTS: return LowerFORMAL_ARGUMENTS(Op, DAG);
+  case ISD::SHL: // FALLTHROUGH
+  case ISD::SRL:
+  case ISD::SRA:              return LowerShifts(Op, DAG);
+  case ISD::GlobalAddress:    return LowerGlobalAddress(Op, DAG);
+  case ISD::ExternalSymbol:   return LowerExternalSymbol(Op, DAG);
+  case ISD::BR_CC:            return LowerBR_CC(Op, DAG);
+  case ISD::SELECT_CC:        return LowerSELECT_CC(Op, DAG);
+  case ISD::SIGN_EXTEND:      return LowerSIGN_EXTEND(Op, DAG);
   default:
-    assert(0 && "unimplemented operand");
+    llvm_unreachable("unimplemented operand");
     return SDValue();
   }
 }
 
+/// getFunctionAlignment - Return the Log2 alignment of this function.
+unsigned MSP430TargetLowering::getFunctionAlignment(const Function *F) const {
+  return F->hasFnAttr(Attribute::OptimizeForSize) ? 1 : 2;
+}
+
+//===----------------------------------------------------------------------===//
+//                       MSP430 Inline Assembly Support
+//===----------------------------------------------------------------------===//
+
+/// getConstraintType - Given a constraint letter, return the type of
+/// constraint it is for this target.
+TargetLowering::ConstraintType
+MSP430TargetLowering::getConstraintType(const std::string &Constraint) const {
+  if (Constraint.size() == 1) {
+    switch (Constraint[0]) {
+    case 'r':
+      return C_RegisterClass;
+    default:
+      break;
+    }
+  }
+  return TargetLowering::getConstraintType(Constraint);
+}
+
+std::pair<unsigned, const TargetRegisterClass*>
+MSP430TargetLowering::
+getRegForInlineAsmConstraint(const std::string &Constraint,
+                             EVT VT) const {
+  if (Constraint.size() == 1) {
+    // GCC Constraint Letters
+    switch (Constraint[0]) {
+    default: break;
+    case 'r':   // GENERAL_REGS
+      if (VT == MVT::i8)
+        return std::make_pair(0U, MSP430::GR8RegisterClass);
+
+      return std::make_pair(0U, MSP430::GR16RegisterClass);
+    }
+  }
+
+  return TargetLowering::getRegForInlineAsmConstraint(Constraint, VT);
+}
+
 //===----------------------------------------------------------------------===//
 //                      Calling Convention Implementation
 //===----------------------------------------------------------------------===//
 
 #include "MSP430GenCallingConv.inc"
 
-SDValue MSP430TargetLowering::LowerFORMAL_ARGUMENTS(SDValue Op,
-                                                    SelectionDAG &DAG) {
-  unsigned CC = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
-  switch (CC) {
+SDValue
+MSP430TargetLowering::LowerFormalArguments(SDValue Chain,
+                                           CallingConv::ID CallConv,
+                                           bool isVarArg,
+                                           const SmallVectorImpl<ISD::InputArg>
+                                             &Ins,
+                                           DebugLoc dl,
+                                           SelectionDAG &DAG,
+                                           SmallVectorImpl<SDValue> &InVals) {
+
+  switch (CallConv) {
   default:
-    assert(0 && "Unsupported calling convention");
+    llvm_unreachable("Unsupported calling convention");
   case CallingConv::C:
   case CallingConv::Fast:
-    return LowerCCCArguments(Op, DAG);
+    return LowerCCCArguments(Chain, CallConv, isVarArg, Ins, dl, DAG, InVals);
+  }
+}
+
+SDValue
+MSP430TargetLowering::LowerCall(SDValue Chain, SDValue Callee,
+                                CallingConv::ID CallConv, bool isVarArg,
+                                bool isTailCall,
+                                const SmallVectorImpl<ISD::OutputArg> &Outs,
+                                const SmallVectorImpl<ISD::InputArg> &Ins,
+                                DebugLoc dl, SelectionDAG &DAG,
+                                SmallVectorImpl<SDValue> &InVals) {
+
+  switch (CallConv) {
+  default:
+    llvm_unreachable("Unsupported calling convention");
+  case CallingConv::Fast:
+  case CallingConv::C:
+    return LowerCCCCallTo(Chain, Callee, CallConv, isVarArg, isTailCall,
+                          Outs, Ins, dl, DAG, InVals);
   }
 }
 
@@ -77,40 +251,46 @@ SDValue MSP430TargetLowering::LowerFORMAL_ARGUMENTS(SDValue Op,
 /// generate load operations for arguments places on the stack.
 // FIXME: struct return stuff
 // FIXME: varargs
-SDValue MSP430TargetLowering:: LowerCCCArguments(SDValue Op,
-                                                 SelectionDAG &DAG) {
+SDValue
+MSP430TargetLowering::LowerCCCArguments(SDValue Chain,
+                                        CallingConv::ID CallConv,
+                                        bool isVarArg,
+                                        const SmallVectorImpl<ISD::InputArg>
+                                          &Ins,
+                                        DebugLoc dl,
+                                        SelectionDAG &DAG,
+                                        SmallVectorImpl<SDValue> &InVals) {
   MachineFunction &MF = DAG.getMachineFunction();
   MachineFrameInfo *MFI = MF.getFrameInfo();
   MachineRegisterInfo &RegInfo = MF.getRegInfo();
-  SDValue Root = Op.getOperand(0);
-  bool isVarArg = cast<ConstantSDNode>(Op.getOperand(2))->getZExtValue() != 0;
-  unsigned CC = MF.getFunction()->getCallingConv();
-  DebugLoc dl = Op.getDebugLoc();
 
   // Assign locations to all of the incoming arguments.
   SmallVector<CCValAssign, 16> ArgLocs;
-  CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs);
-  CCInfo.AnalyzeFormalArguments(Op.getNode(), CC_MSP430);
+  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
+                 ArgLocs, *DAG.getContext());
+  CCInfo.AnalyzeFormalArguments(Ins, CC_MSP430);
 
   assert(!isVarArg && "Varargs not supported yet");
 
-  SmallVector<SDValue, 16> ArgValues;
   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
     CCValAssign &VA = ArgLocs[i];
     if (VA.isRegLoc()) {
       // Arguments passed in registers
-      MVT RegVT = VA.getLocVT();
-      switch (RegVT.getSimpleVT()) {
-      default:
-        cerr << "LowerFORMAL_ARGUMENTS Unhandled argument type: "
-             << RegVT.getSimpleVT()
-             << "\n";
-        abort();
+      EVT RegVT = VA.getLocVT();
+      switch (RegVT.getSimpleVT().SimpleTy) {
+      default: 
+        {
+#ifndef NDEBUG
+          errs() << "LowerFormalArguments Unhandled argument type: "
+               << RegVT.getSimpleVT().SimpleTy << "\n";
+#endif
+          llvm_unreachable(0);
+        }
       case MVT::i16:
         unsigned VReg =
-          RegInfo.createVirtualRegister(MSP430::MSP430RegsRegisterClass);
+          RegInfo.createVirtualRegister(MSP430::GR16RegisterClass);
         RegInfo.addLiveIn(VA.getLocReg(), VReg);
-        SDValue ArgValue = DAG.getCopyFromReg(Root, dl, VReg, RegVT);
+        SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, VReg, RegVT);
 
         // If this is an 8-bit value, it is really passed promoted to 16
         // bits. Insert an assert[sz]ext to capture this, then truncate to the
@@ -125,7 +305,7 @@ SDValue MSP430TargetLowering:: LowerCCCArguments(SDValue Op,
         if (VA.getLocInfo() != CCValAssign::Full)
           ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
 
-        ArgValues.push_back(ArgValue);
+        InVals.push_back(ArgValue);
       }
     } else {
       // Sanity check
@@ -133,24 +313,483 @@ SDValue MSP430TargetLowering:: LowerCCCArguments(SDValue Op,
       // Load the argument to a virtual register
       unsigned ObjSize = VA.getLocVT().getSizeInBits()/8;
       if (ObjSize > 2) {
-        cerr << "LowerFORMAL_ARGUMENTS Unhandled argument type: "
-             << VA.getLocVT().getSimpleVT()
+        errs() << "LowerFormalArguments Unhandled argument type: "
+             << VA.getLocVT().getSimpleVT().SimpleTy
              << "\n";
       }
       // Create the frame index object for this incoming parameter...
-      int FI = MFI->CreateFixedObject(ObjSize, VA.getLocMemOffset());
+      int FI = MFI->CreateFixedObject(ObjSize, VA.getLocMemOffset(), true, false);
 
       // Create the SelectionDAG nodes corresponding to a load
       //from this parameter
       SDValue FIN = DAG.getFrameIndex(FI, MVT::i16);
-      ArgValues.push_back(DAG.getLoad(VA.getLocVT(), dl, Root, FIN,
-                                      PseudoSourceValue::getFixedStack(FI), 0));
+      InVals.push_back(DAG.getLoad(VA.getLocVT(), dl, Chain, FIN,
+                                   PseudoSourceValue::getFixedStack(FI), 0));
+    }
+  }
+
+  return Chain;
+}
+
+SDValue
+MSP430TargetLowering::LowerReturn(SDValue Chain,
+                                  CallingConv::ID CallConv, bool isVarArg,
+                                  const SmallVectorImpl<ISD::OutputArg> &Outs,
+                                  DebugLoc dl, SelectionDAG &DAG) {
+
+  // CCValAssign - represent the assignment of the return value to a location
+  SmallVector<CCValAssign, 16> RVLocs;
+
+  // CCState - Info about the registers and stack slot.
+  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
+                 RVLocs, *DAG.getContext());
+
+  // Analize return values.
+  CCInfo.AnalyzeReturn(Outs, RetCC_MSP430);
+
+  // If this is the first return lowered for this function, add the regs to the
+  // liveout set for the function.
+  if (DAG.getMachineFunction().getRegInfo().liveout_empty()) {
+    for (unsigned i = 0; i != RVLocs.size(); ++i)
+      if (RVLocs[i].isRegLoc())
+        DAG.getMachineFunction().getRegInfo().addLiveOut(RVLocs[i].getLocReg());
+  }
+
+  SDValue Flag;
+
+  // Copy the result values into the output registers.
+  for (unsigned i = 0; i != RVLocs.size(); ++i) {
+    CCValAssign &VA = RVLocs[i];
+    assert(VA.isRegLoc() && "Can only return in registers!");
+
+    Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(),
+                             Outs[i].Val, Flag);
+
+    // Guarantee that all emitted copies are stuck together,
+    // avoiding something bad.
+    Flag = Chain.getValue(1);
+  }
+
+  if (Flag.getNode())
+    return DAG.getNode(MSP430ISD::RET_FLAG, dl, MVT::Other, Chain, Flag);
+
+  // Return Void
+  return DAG.getNode(MSP430ISD::RET_FLAG, dl, MVT::Other, Chain);
+}
+
+/// LowerCCCCallTo - functions arguments are copied from virtual regs to
+/// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
+/// TODO: sret.
+SDValue
+MSP430TargetLowering::LowerCCCCallTo(SDValue Chain, SDValue Callee,
+                                     CallingConv::ID CallConv, bool isVarArg,
+                                     bool isTailCall,
+                                     const SmallVectorImpl<ISD::OutputArg>
+                                       &Outs,
+                                     const SmallVectorImpl<ISD::InputArg> &Ins,
+                                     DebugLoc dl, SelectionDAG &DAG,
+                                     SmallVectorImpl<SDValue> &InVals) {
+  // Analyze operands of the call, assigning locations to each operand.
+  SmallVector<CCValAssign, 16> ArgLocs;
+  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
+                 ArgLocs, *DAG.getContext());
+
+  CCInfo.AnalyzeCallOperands(Outs, CC_MSP430);
+
+  // Get a count of how many bytes are to be pushed on the stack.
+  unsigned NumBytes = CCInfo.getNextStackOffset();
+
+  Chain = DAG.getCALLSEQ_START(Chain ,DAG.getConstant(NumBytes,
+                                                      getPointerTy(), true));
+
+  SmallVector<std::pair<unsigned, SDValue>, 4> RegsToPass;
+  SmallVector<SDValue, 12> MemOpChains;
+  SDValue StackPtr;
+
+  // Walk the register/memloc assignments, inserting copies/loads.
+  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
+    CCValAssign &VA = ArgLocs[i];
+
+    SDValue Arg = Outs[i].Val;
+
+    // Promote the value if needed.
+    switch (VA.getLocInfo()) {
+      default: llvm_unreachable("Unknown loc info!");
+      case CCValAssign::Full: break;
+      case CCValAssign::SExt:
+        Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
+        break;
+      case CCValAssign::ZExt:
+        Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
+        break;
+      case CCValAssign::AExt:
+        Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
+        break;
+    }
+
+    // Arguments that can be passed on register must be kept at RegsToPass
+    // vector
+    if (VA.isRegLoc()) {
+      RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
+    } else {
+      assert(VA.isMemLoc());
+
+      if (StackPtr.getNode() == 0)
+        StackPtr = DAG.getCopyFromReg(Chain, dl, MSP430::SPW, getPointerTy());
+
+      SDValue PtrOff = DAG.getNode(ISD::ADD, dl, getPointerTy(),
+                                   StackPtr,
+                                   DAG.getIntPtrConstant(VA.getLocMemOffset()));
+
+
+      MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, PtrOff,
+                                         PseudoSourceValue::getStack(),
+                                         VA.getLocMemOffset()));
     }
   }
 
-  ArgValues.push_back(Root);
+  // Transform all store nodes into one single node because all store nodes are
+  // independent of each other.
+  if (!MemOpChains.empty())
+    Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
+                        &MemOpChains[0], MemOpChains.size());
+
+  // Build a sequence of copy-to-reg nodes chained together with token chain and
+  // flag operands which copy the outgoing args into registers.  The InFlag in
+  // necessary since all emited instructions must be stuck together.
+  SDValue InFlag;
+  for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
+    Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
+                             RegsToPass[i].second, InFlag);
+    InFlag = Chain.getValue(1);
+  }
+
+  // If the callee is a GlobalAddress node (quite common, every direct call is)
+  // turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
+  // Likewise ExternalSymbol -> TargetExternalSymbol.
+  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
+    Callee = DAG.getTargetGlobalAddress(G->getGlobal(), MVT::i16);
+  else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee))
+    Callee = DAG.getTargetExternalSymbol(E->getSymbol(), MVT::i16);
+
+  // Returns a chain & a flag for retval copy to use.
+  SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
+  SmallVector<SDValue, 8> Ops;
+  Ops.push_back(Chain);
+  Ops.push_back(Callee);
+
+  // Add argument registers to the end of the list so that they are
+  // known live into the call.
+  for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
+    Ops.push_back(DAG.getRegister(RegsToPass[i].first,
+                                  RegsToPass[i].second.getValueType()));
+
+  if (InFlag.getNode())
+    Ops.push_back(InFlag);
+
+  Chain = DAG.getNode(MSP430ISD::CALL, dl, NodeTys, &Ops[0], Ops.size());
+  InFlag = Chain.getValue(1);
+
+  // Create the CALLSEQ_END node.
+  Chain = DAG.getCALLSEQ_END(Chain,
+                             DAG.getConstant(NumBytes, getPointerTy(), true),
+                             DAG.getConstant(0, getPointerTy(), true),
+                             InFlag);
+  InFlag = Chain.getValue(1);
+
+  // Handle result values, copying them out of physregs into vregs that we
+  // return.
+  return LowerCallResult(Chain, InFlag, CallConv, isVarArg, Ins, dl,
+                         DAG, InVals);
+}
+
+/// LowerCallResult - Lower the result values of a call into the
+/// appropriate copies out of appropriate physical registers.
+///
+SDValue
+MSP430TargetLowering::LowerCallResult(SDValue Chain, SDValue InFlag,
+                                      CallingConv::ID CallConv, bool isVarArg,
+                                      const SmallVectorImpl<ISD::InputArg> &Ins,
+                                      DebugLoc dl, SelectionDAG &DAG,
+                                      SmallVectorImpl<SDValue> &InVals) {
+
+  // Assign locations to each value returned by this call.
+  SmallVector<CCValAssign, 16> RVLocs;
+  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
+                 RVLocs, *DAG.getContext());
+
+  CCInfo.AnalyzeCallResult(Ins, RetCC_MSP430);
+
+  // Copy all of the result registers out of their specified physreg.
+  for (unsigned i = 0; i != RVLocs.size(); ++i) {
+    Chain = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(),
+                               RVLocs[i].getValVT(), InFlag).getValue(1);
+    InFlag = Chain.getValue(2);
+    InVals.push_back(Chain.getValue(0));
+  }
+
+  return Chain;
+}
+
+SDValue MSP430TargetLowering::LowerShifts(SDValue Op,
+                                          SelectionDAG &DAG) {
+  unsigned Opc = Op.getOpcode();
+  SDNode* N = Op.getNode();
+  EVT VT = Op.getValueType();
+  DebugLoc dl = N->getDebugLoc();
+
+  // We currently only lower shifts of constant argument.
+  if (!isa<ConstantSDNode>(N->getOperand(1)))
+    return SDValue();
+
+  uint64_t ShiftAmount = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue();
+
+  // Expand the stuff into sequence of shifts.
+  // FIXME: for some shift amounts this might be done better!
+  // E.g.: foo >> (8 + N) => sxt(swpb(foo)) >> N
+  SDValue Victim = N->getOperand(0);
+
+  if (Opc == ISD::SRL && ShiftAmount) {
+    // Emit a special goodness here:
+    // srl A, 1 => clrc; rrc A
+    Victim = DAG.getNode(MSP430ISD::RRC, dl, VT, Victim);
+    ShiftAmount -= 1;
+  }
+
+  while (ShiftAmount--)
+    Victim = DAG.getNode((Opc == ISD::SHL ? MSP430ISD::RLA : MSP430ISD::RRA),
+                         dl, VT, Victim);
+
+  return Victim;
+}
+
+SDValue MSP430TargetLowering::LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) {
+  const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
+  int64_t Offset = cast<GlobalAddressSDNode>(Op)->getOffset();
+
+  // Create the TargetGlobalAddress node, folding in the constant offset.
+  SDValue Result = DAG.getTargetGlobalAddress(GV, getPointerTy(), Offset);
+  return DAG.getNode(MSP430ISD::Wrapper, Op.getDebugLoc(),
+                     getPointerTy(), Result);
+}
+
+SDValue MSP430TargetLowering::LowerExternalSymbol(SDValue Op,
+                                                  SelectionDAG &DAG) {
+  DebugLoc dl = Op.getDebugLoc();
+  const char *Sym = cast<ExternalSymbolSDNode>(Op)->getSymbol();
+  SDValue Result = DAG.getTargetExternalSymbol(Sym, getPointerTy());
+
+  return DAG.getNode(MSP430ISD::Wrapper, dl, getPointerTy(), Result);;
+}
+
+static SDValue EmitCMP(SDValue &LHS, SDValue &RHS, SDValue &TargetCC,
+                       ISD::CondCode CC,
+                       DebugLoc dl, SelectionDAG &DAG) {
+  // FIXME: Handle bittests someday
+  assert(!LHS.getValueType().isFloatingPoint() && "We don't handle FP yet");
+
+  // FIXME: Handle jump negative someday
+  MSP430CC::CondCodes TCC = MSP430CC::COND_INVALID;
+  switch (CC) {
+  default: llvm_unreachable("Invalid integer condition!");
+  case ISD::SETEQ:
+    TCC = MSP430CC::COND_E;     // aka COND_Z
+    break;
+  case ISD::SETNE:
+    TCC = MSP430CC::COND_NE;    // aka COND_NZ
+    break;
+  case ISD::SETULE:
+    std::swap(LHS, RHS);        // FALLTHROUGH
+  case ISD::SETUGE:
+    TCC = MSP430CC::COND_HS;    // aka COND_C
+    break;
+  case ISD::SETUGT:
+    std::swap(LHS, RHS);        // FALLTHROUGH
+  case ISD::SETULT:
+    TCC = MSP430CC::COND_LO;    // aka COND_NC
+    break;
+  case ISD::SETLE:
+    std::swap(LHS, RHS);        // FALLTHROUGH
+  case ISD::SETGE:
+    TCC = MSP430CC::COND_GE;
+    break;
+  case ISD::SETGT:
+    std::swap(LHS, RHS);        // FALLTHROUGH
+  case ISD::SETLT:
+    TCC = MSP430CC::COND_L;
+    break;
+  }
+
+  TargetCC = DAG.getConstant(TCC, MVT::i8);
+  return DAG.getNode(MSP430ISD::CMP, dl, MVT::Flag, LHS, RHS);
+}
+
+
+SDValue MSP430TargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) {
+  SDValue Chain = Op.getOperand(0);
+  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(1))->get();
+  SDValue LHS   = Op.getOperand(2);
+  SDValue RHS   = Op.getOperand(3);
+  SDValue Dest  = Op.getOperand(4);
+  DebugLoc dl   = Op.getDebugLoc();
+
+  SDValue TargetCC;
+  SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
+
+  return DAG.getNode(MSP430ISD::BR_CC, dl, Op.getValueType(),
+                     Chain, Dest, TargetCC, Flag);
+}
+
+SDValue MSP430TargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) {
+  SDValue LHS    = Op.getOperand(0);
+  SDValue RHS    = Op.getOperand(1);
+  SDValue TrueV  = Op.getOperand(2);
+  SDValue FalseV = Op.getOperand(3);
+  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
+  DebugLoc dl    = Op.getDebugLoc();
+
+  SDValue TargetCC;
+  SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
+
+  SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Flag);
+  SmallVector<SDValue, 4> Ops;
+  Ops.push_back(TrueV);
+  Ops.push_back(FalseV);
+  Ops.push_back(TargetCC);
+  Ops.push_back(Flag);
+
+  return DAG.getNode(MSP430ISD::SELECT_CC, dl, VTs, &Ops[0], Ops.size());
+}
+
+SDValue MSP430TargetLowering::LowerSIGN_EXTEND(SDValue Op,
+                                               SelectionDAG &DAG) {
+  SDValue Val = Op.getOperand(0);
+  EVT VT      = Op.getValueType();
+  DebugLoc dl = Op.getDebugLoc();
+
+  assert(VT == MVT::i16 && "Only support i16 for now!");
+
+  return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, VT,
+                     DAG.getNode(ISD::ANY_EXTEND, dl, VT, Val),
+                     DAG.getValueType(Val.getValueType()));
+}
+
+/// getPostIndexedAddressParts - returns true by value, base pointer and
+/// offset pointer and addressing mode by reference if this node can be
+/// combined with a load / store to form a post-indexed load / store.
+bool MSP430TargetLowering::getPostIndexedAddressParts(SDNode *N, SDNode *Op,
+                                                      SDValue &Base,
+                                                      SDValue &Offset,
+                                                      ISD::MemIndexedMode &AM,
+                                                      SelectionDAG &DAG) const {
+
+  LoadSDNode *LD = cast<LoadSDNode>(N);
+  if (LD->getExtensionType() != ISD::NON_EXTLOAD)
+    return false;
+
+  EVT VT = LD->getMemoryVT();
+  if (VT != MVT::i8 && VT != MVT::i16)
+    return false;
+
+  if (Op->getOpcode() != ISD::ADD)
+    return false;
+
+  if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(Op->getOperand(1))) {
+    uint64_t RHSC = RHS->getZExtValue();
+    if ((VT == MVT::i16 && RHSC != 2) ||
+        (VT == MVT::i8 && RHSC != 1))
+      return false;
+
+    Base = Op->getOperand(0);
+    Offset = DAG.getConstant(RHSC, VT);
+    AM = ISD::POST_INC;
+    return true;
+  }
+
+  return false;
+}
+
+
+const char *MSP430TargetLowering::getTargetNodeName(unsigned Opcode) const {
+  switch (Opcode) {
+  default: return NULL;
+  case MSP430ISD::RET_FLAG:           return "MSP430ISD::RET_FLAG";
+  case MSP430ISD::RRA:                return "MSP430ISD::RRA";
+  case MSP430ISD::RLA:                return "MSP430ISD::RLA";
+  case MSP430ISD::RRC:                return "MSP430ISD::RRC";
+  case MSP430ISD::CALL:               return "MSP430ISD::CALL";
+  case MSP430ISD::Wrapper:            return "MSP430ISD::Wrapper";
+  case MSP430ISD::BR_CC:              return "MSP430ISD::BR_CC";
+  case MSP430ISD::CMP:                return "MSP430ISD::CMP";
+  case MSP430ISD::SELECT_CC:          return "MSP430ISD::SELECT_CC";
+  }
+}
+
+//===----------------------------------------------------------------------===//
+//  Other Lowering Code
+//===----------------------------------------------------------------------===//
+
+MachineBasicBlock*
+MSP430TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
+                                                  MachineBasicBlock *BB,
+                   DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM) const {
+  const TargetInstrInfo &TII = *getTargetMachine().getInstrInfo();
+  DebugLoc dl = MI->getDebugLoc();
+  assert((MI->getOpcode() == MSP430::Select16 ||
+          MI->getOpcode() == MSP430::Select8) &&
+         "Unexpected instr type to insert");
+
+  // To "insert" a SELECT instruction, we actually have to insert the diamond
+  // control-flow pattern.  The incoming instruction knows the destination vreg
+  // to set, the condition code register to branch on, the true/false values to
+  // select between, and a branch opcode to use.
+  const BasicBlock *LLVM_BB = BB->getBasicBlock();
+  MachineFunction::iterator I = BB;
+  ++I;
+
+  //  thisMBB:
+  //  ...
+  //   TrueVal = ...
+  //   cmpTY ccX, r1, r2
+  //   jCC copy1MBB
+  //   fallthrough --> copy0MBB
+  MachineBasicBlock *thisMBB = BB;
+  MachineFunction *F = BB->getParent();
+  MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
+  MachineBasicBlock *copy1MBB = F->CreateMachineBasicBlock(LLVM_BB);
+  BuildMI(BB, dl, TII.get(MSP430::JCC))
+    .addMBB(copy1MBB)
+    .addImm(MI->getOperand(3).getImm());
+  F->insert(I, copy0MBB);
+  F->insert(I, copy1MBB);
+  // Inform sdisel of the edge changes.
+  for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(), 
+         SE = BB->succ_end(); SI != SE; ++SI)
+    EM->insert(std::make_pair(*SI, copy1MBB));
+  // Update machine-CFG edges by transferring all successors of the current
+  // block to the new block which will contain the Phi node for the select.
+  copy1MBB->transferSuccessors(BB);
+  // Next, add the true and fallthrough blocks as its successors.
+  BB->addSuccessor(copy0MBB);
+  BB->addSuccessor(copy1MBB);
+
+  //  copy0MBB:
+  //   %FalseValue = ...
+  //   # fallthrough to copy1MBB
+  BB = copy0MBB;
+
+  // Update machine-CFG edges
+  BB->addSuccessor(copy1MBB);
+
+  //  copy1MBB:
+  //   %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
+  //  ...
+  BB = copy1MBB;
+  BuildMI(BB, dl, TII.get(MSP430::PHI),
+          MI->getOperand(0).getReg())
+    .addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB)
+    .addReg(MI->getOperand(1).getReg()).addMBB(thisMBB);
 
-  // Return the new list of results.
-  return DAG.getNode(ISD::MERGE_VALUES, dl, Op.getNode()->getVTList(),
-                     &ArgValues[0], ArgValues.size()).getValue(Op.getResNo());
+  F->DeleteMachineInstr(MI);   // The pseudo instruction is gone now.
+  return BB;
 }