It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/IA64/IA64ISelLowering.cpp b/lib/Target/IA64/IA64ISelLowering.cpp
new file mode 100644
index 0000000..0237a9a
--- /dev/null
+++ b/lib/Target/IA64/IA64ISelLowering.cpp
@@ -0,0 +1,602 @@
+//===-- IA64ISelLowering.cpp - IA64 DAG Lowering Implementation -----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Duraid Madina and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the IA64ISelLowering class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "IA64ISelLowering.h"
+#include "IA64MachineFunctionInfo.h"
+#include "IA64TargetMachine.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/SSARegMap.h"
+#include "llvm/Constants.h"
+#include "llvm/Function.h"
+using namespace llvm;
+
+IA64TargetLowering::IA64TargetLowering(TargetMachine &TM)
+  : TargetLowering(TM) {
+ 
+      // register class for general registers
+      addRegisterClass(MVT::i64, IA64::GRRegisterClass);
+
+      // register class for FP registers
+      addRegisterClass(MVT::f64, IA64::FPRegisterClass);
+
+      // register class for predicate registers
+      addRegisterClass(MVT::i1, IA64::PRRegisterClass);
+
+      setLoadXAction(ISD::EXTLOAD          , MVT::i1   , Promote);
+
+      setLoadXAction(ISD::ZEXTLOAD         , MVT::i1   , Expand);
+
+      setLoadXAction(ISD::SEXTLOAD         , MVT::i1   , Expand);
+      setLoadXAction(ISD::SEXTLOAD         , MVT::i8   , Expand);
+      setLoadXAction(ISD::SEXTLOAD         , MVT::i16  , Expand);
+      setLoadXAction(ISD::SEXTLOAD         , MVT::i32  , Expand);
+
+      setOperationAction(ISD::BRIND            , MVT::Other, Expand);
+      setOperationAction(ISD::BR_JT            , MVT::Other, Expand);
+      setOperationAction(ISD::BR_CC            , MVT::Other, Expand);
+      setOperationAction(ISD::FP_ROUND_INREG   , MVT::f32  , Expand);
+
+      // ia64 uses SELECT not SELECT_CC
+      setOperationAction(ISD::SELECT_CC        , MVT::Other,  Expand);
+      
+      // We need to handle ISD::RET for void functions ourselves,
+      // so we get a chance to restore ar.pfs before adding a
+      // br.ret insn
+      setOperationAction(ISD::RET, MVT::Other, Custom);
+
+      setSetCCResultType(MVT::i1);
+      setShiftAmountType(MVT::i64);
+
+      setOperationAction(ISD::FREM             , MVT::f32  , Expand);
+      setOperationAction(ISD::FREM             , MVT::f64  , Expand);
+
+      setOperationAction(ISD::UREM             , MVT::f32  , Expand);
+      setOperationAction(ISD::UREM             , MVT::f64  , Expand);
+
+      setOperationAction(ISD::MEMMOVE          , MVT::Other, Expand);
+      setOperationAction(ISD::MEMSET           , MVT::Other, Expand);
+      setOperationAction(ISD::MEMCPY           , MVT::Other, Expand);
+      
+      setOperationAction(ISD::SINT_TO_FP       , MVT::i1   , Promote);
+      setOperationAction(ISD::UINT_TO_FP       , MVT::i1   , Promote);
+
+      // We don't support sin/cos/sqrt
+      setOperationAction(ISD::FSIN , MVT::f64, Expand);
+      setOperationAction(ISD::FCOS , MVT::f64, Expand);
+      setOperationAction(ISD::FSQRT, MVT::f64, Expand);
+      setOperationAction(ISD::FSIN , MVT::f32, Expand);
+      setOperationAction(ISD::FCOS , MVT::f32, Expand);
+      setOperationAction(ISD::FSQRT, MVT::f32, Expand);
+
+      // FIXME: IA64 supports fcopysign natively!
+      setOperationAction(ISD::FCOPYSIGN, MVT::f64, Expand);
+      setOperationAction(ISD::FCOPYSIGN, MVT::f32, Expand);
+      
+      // We don't have line number support yet.
+      setOperationAction(ISD::LOCATION, MVT::Other, Expand);
+      setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand);
+      setOperationAction(ISD::LABEL, MVT::Other, Expand);
+
+      //IA64 has these, but they are not implemented
+      setOperationAction(ISD::CTTZ , MVT::i64  , Expand);
+      setOperationAction(ISD::CTLZ , MVT::i64  , Expand);
+      setOperationAction(ISD::ROTL , MVT::i64  , Expand);
+      setOperationAction(ISD::ROTR , MVT::i64  , Expand);
+      setOperationAction(ISD::BSWAP, MVT::i64  , Expand);  // mux @rev
+
+      // VASTART needs to be custom lowered to use the VarArgsFrameIndex
+      setOperationAction(ISD::VAARG             , MVT::Other, Custom);
+      setOperationAction(ISD::VASTART           , MVT::Other, Custom);
+      
+      // Use the default implementation.
+      setOperationAction(ISD::VACOPY            , MVT::Other, Expand);
+      setOperationAction(ISD::VAEND             , MVT::Other, Expand);
+      setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
+      setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
+      setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i64, Expand);
+
+      // Thread Local Storage
+      setOperationAction(ISD::GlobalTLSAddress, MVT::i64, Custom);
+
+      setStackPointerRegisterToSaveRestore(IA64::r12);
+
+      setJumpBufSize(704); // on ia64-linux, jmp_bufs are 704 bytes..
+      setJumpBufAlignment(16); // ...and must be 16-byte aligned
+      
+      computeRegisterProperties();
+
+      setOperationAction(ISD::ConstantFP, MVT::f64, Expand);
+      addLegalFPImmediate(+0.0);
+      addLegalFPImmediate(+1.0);
+}
+
+const char *IA64TargetLowering::getTargetNodeName(unsigned Opcode) const {
+  switch (Opcode) {
+  default: return 0;
+  case IA64ISD::GETFD:  return "IA64ISD::GETFD";
+  case IA64ISD::BRCALL: return "IA64ISD::BRCALL";  
+  case IA64ISD::RET_FLAG: return "IA64ISD::RET_FLAG";
+  }
+}
+  
+
+std::vector<SDOperand>
+IA64TargetLowering::LowerArguments(Function &F, SelectionDAG &DAG) {
+  std::vector<SDOperand> ArgValues;
+  //
+  // add beautiful description of IA64 stack frame format
+  // here (from intel 24535803.pdf most likely)
+  //
+  MachineFunction &MF = DAG.getMachineFunction();
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  
+  GP = MF.getSSARegMap()->createVirtualRegister(getRegClassFor(MVT::i64));
+  SP = MF.getSSARegMap()->createVirtualRegister(getRegClassFor(MVT::i64));
+  RP = MF.getSSARegMap()->createVirtualRegister(getRegClassFor(MVT::i64));
+  
+  MachineBasicBlock& BB = MF.front();
+
+  unsigned args_int[] = {IA64::r32, IA64::r33, IA64::r34, IA64::r35,
+                         IA64::r36, IA64::r37, IA64::r38, IA64::r39};
+
+  unsigned args_FP[] = {IA64::F8, IA64::F9, IA64::F10, IA64::F11,
+                        IA64::F12,IA64::F13,IA64::F14, IA64::F15};
+
+  unsigned argVreg[8];
+  unsigned argPreg[8];
+  unsigned argOpc[8];
+
+  unsigned used_FPArgs = 0; // how many FP args have been used so far?
+
+  unsigned ArgOffset = 0;
+  int count = 0;
+
+  for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
+    {
+      SDOperand newroot, argt;
+      if(count < 8) { // need to fix this logic? maybe.
+
+        switch (getValueType(I->getType())) {
+          default:
+            assert(0 && "ERROR in LowerArgs: can't lower this type of arg.\n"); 
+          case MVT::f32:
+            // fixme? (well, will need to for weird FP structy stuff,
+            // see intel ABI docs)
+          case MVT::f64:
+//XXX            BuildMI(&BB, IA64::IDEF, 0, args_FP[used_FPArgs]);
+            MF.addLiveIn(args_FP[used_FPArgs]); // mark this reg as liveIn
+            // floating point args go into f8..f15 as-needed, the increment
+            argVreg[count] =                              // is below..:
+            MF.getSSARegMap()->createVirtualRegister(getRegClassFor(MVT::f64));
+            // FP args go into f8..f15 as needed: (hence the ++)
+            argPreg[count] = args_FP[used_FPArgs++];
+            argOpc[count] = IA64::FMOV;
+            argt = newroot = DAG.getCopyFromReg(DAG.getRoot(), argVreg[count],
+                                                MVT::f64);
+            if (I->getType() == Type::FloatTy)
+              argt = DAG.getNode(ISD::FP_ROUND, MVT::f32, argt);
+            break;
+          case MVT::i1: // NOTE: as far as C abi stuff goes,
+                        // bools are just boring old ints
+          case MVT::i8:
+          case MVT::i16:
+          case MVT::i32:
+          case MVT::i64:
+//XXX            BuildMI(&BB, IA64::IDEF, 0, args_int[count]);
+            MF.addLiveIn(args_int[count]); // mark this register as liveIn
+            argVreg[count] =
+            MF.getSSARegMap()->createVirtualRegister(getRegClassFor(MVT::i64));
+            argPreg[count] = args_int[count];
+            argOpc[count] = IA64::MOV;
+            argt = newroot =
+              DAG.getCopyFromReg(DAG.getRoot(), argVreg[count], MVT::i64);
+            if ( getValueType(I->getType()) != MVT::i64)
+              argt = DAG.getNode(ISD::TRUNCATE, getValueType(I->getType()),
+                  newroot);
+            break;
+        }
+      } else { // more than 8 args go into the frame
+        // Create the frame index object for this incoming parameter...
+        ArgOffset = 16 + 8 * (count - 8);
+        int FI = MFI->CreateFixedObject(8, ArgOffset);
+
+        // Create the SelectionDAG nodes corresponding to a load
+        //from this parameter
+        SDOperand FIN = DAG.getFrameIndex(FI, MVT::i64);
+        argt = newroot = DAG.getLoad(getValueType(I->getType()),
+                                     DAG.getEntryNode(), FIN, NULL, 0);
+      }
+      ++count;
+      DAG.setRoot(newroot.getValue(1));
+      ArgValues.push_back(argt);
+    }
+
+
+  // Create a vreg to hold the output of (what will become)
+  // the "alloc" instruction
+  VirtGPR = MF.getSSARegMap()->createVirtualRegister(getRegClassFor(MVT::i64));
+  BuildMI(&BB, TII->get(IA64::PSEUDO_ALLOC), VirtGPR);
+  // we create a PSEUDO_ALLOC (pseudo)instruction for now
+/*
+  BuildMI(&BB, IA64::IDEF, 0, IA64::r1);
+
+  // hmm:
+  BuildMI(&BB, IA64::IDEF, 0, IA64::r12);
+  BuildMI(&BB, IA64::IDEF, 0, IA64::rp);
+  // ..hmm.
+  
+  BuildMI(&BB, IA64::MOV, 1, GP).addReg(IA64::r1);
+
+  // hmm:
+  BuildMI(&BB, IA64::MOV, 1, SP).addReg(IA64::r12);
+  BuildMI(&BB, IA64::MOV, 1, RP).addReg(IA64::rp);
+  // ..hmm.
+*/
+
+  unsigned tempOffset=0;
+
+  // if this is a varargs function, we simply lower llvm.va_start by
+  // pointing to the first entry
+  if(F.isVarArg()) {
+    tempOffset=0;
+    VarArgsFrameIndex = MFI->CreateFixedObject(8, tempOffset);
+  }
+
+  // here we actually do the moving of args, and store them to the stack
+  // too if this is a varargs function:
+  for (int i = 0; i < count && i < 8; ++i) {
+    BuildMI(&BB, TII->get(argOpc[i]), argVreg[i]).addReg(argPreg[i]);
+    if(F.isVarArg()) {
+      // if this is a varargs function, we copy the input registers to the stack
+      int FI = MFI->CreateFixedObject(8, tempOffset);
+      tempOffset+=8;   //XXX: is it safe to use r22 like this?
+      BuildMI(&BB, TII->get(IA64::MOV), IA64::r22).addFrameIndex(FI);
+      // FIXME: we should use st8.spill here, one day
+      BuildMI(&BB, TII->get(IA64::ST8), IA64::r22).addReg(argPreg[i]);
+    }
+  }
+
+  // Finally, inform the code generator which regs we return values in.
+  // (see the ISD::RET: case in the instruction selector)
+  switch (getValueType(F.getReturnType())) {
+  default: assert(0 && "i have no idea where to return this type!");
+  case MVT::isVoid: break;
+  case MVT::i1:
+  case MVT::i8:
+  case MVT::i16:
+  case MVT::i32:
+  case MVT::i64:
+    MF.addLiveOut(IA64::r8);
+    break;
+  case MVT::f32:
+  case MVT::f64:
+    MF.addLiveOut(IA64::F8);
+    break;
+  }
+
+  return ArgValues;
+}
+
+std::pair<SDOperand, SDOperand>
+IA64TargetLowering::LowerCallTo(SDOperand Chain,
+                                const Type *RetTy, bool RetTyIsSigned, 
+                                bool isVarArg, unsigned CallingConv, 
+                                bool isTailCall, SDOperand Callee, 
+                                ArgListTy &Args, SelectionDAG &DAG) {
+
+  MachineFunction &MF = DAG.getMachineFunction();
+
+  unsigned NumBytes = 16;
+  unsigned outRegsUsed = 0;
+
+  if (Args.size() > 8) {
+    NumBytes += (Args.size() - 8) * 8;
+    outRegsUsed = 8;
+  } else {
+    outRegsUsed = Args.size();
+  }
+
+  // FIXME? this WILL fail if we ever try to pass around an arg that
+  // consumes more than a single output slot (a 'real' double, int128
+  // some sort of aggregate etc.), as we'll underestimate how many 'outX'
+  // registers we use. Hopefully, the assembler will notice.
+  MF.getInfo<IA64FunctionInfo>()->outRegsUsed=
+    std::max(outRegsUsed, MF.getInfo<IA64FunctionInfo>()->outRegsUsed);
+
+  // keep stack frame 16-byte aligned
+  // assert(NumBytes==((NumBytes+15) & ~15) && 
+  //        "stack frame not 16-byte aligned!");
+  NumBytes = (NumBytes+15) & ~15;
+  
+  Chain = DAG.getCALLSEQ_START(Chain,DAG.getConstant(NumBytes, getPointerTy()));
+
+  SDOperand StackPtr;
+  std::vector<SDOperand> Stores;
+  std::vector<SDOperand> Converts;
+  std::vector<SDOperand> RegValuesToPass;
+  unsigned ArgOffset = 16;
+  
+  for (unsigned i = 0, e = Args.size(); i != e; ++i)
+    {
+      SDOperand Val = Args[i].Node;
+      MVT::ValueType ObjectVT = Val.getValueType();
+      SDOperand ValToStore(0, 0), ValToConvert(0, 0);
+      unsigned ObjSize=8;
+      switch (ObjectVT) {
+      default: assert(0 && "unexpected argument type!");
+      case MVT::i1:
+      case MVT::i8:
+      case MVT::i16:
+      case MVT::i32: {
+        //promote to 64-bits, sign/zero extending based on type
+        //of the argument
+        ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
+        if (Args[i].isSExt)
+          ExtendKind = ISD::SIGN_EXTEND;
+        else if (Args[i].isZExt)
+          ExtendKind = ISD::ZERO_EXTEND;
+        Val = DAG.getNode(ExtendKind, MVT::i64, Val);
+        // XXX: fall through
+      }
+      case MVT::i64:
+        //ObjSize = 8;
+        if(RegValuesToPass.size() >= 8) {
+          ValToStore = Val;
+        } else {
+          RegValuesToPass.push_back(Val);
+        }
+        break;
+      case MVT::f32:
+        //promote to 64-bits
+        Val = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Val);
+        // XXX: fall through
+      case MVT::f64:
+        if(RegValuesToPass.size() >= 8) {
+          ValToStore = Val;
+        } else {
+          RegValuesToPass.push_back(Val);
+          if(1 /* TODO: if(calling external or varadic function)*/ ) {
+            ValToConvert = Val; // additionally pass this FP value as an int
+          }
+        }
+        break;
+      }
+      
+      if(ValToStore.Val) {
+        if(!StackPtr.Val) {
+          StackPtr = DAG.getRegister(IA64::r12, MVT::i64);
+        }
+        SDOperand PtrOff = DAG.getConstant(ArgOffset, getPointerTy());
+        PtrOff = DAG.getNode(ISD::ADD, MVT::i64, StackPtr, PtrOff);
+        Stores.push_back(DAG.getStore(Chain, ValToStore, PtrOff, NULL, 0));
+        ArgOffset += ObjSize;
+      }
+
+      if(ValToConvert.Val) {
+        Converts.push_back(DAG.getNode(IA64ISD::GETFD, MVT::i64, ValToConvert)); 
+      }
+    }
+
+  // Emit all stores, make sure they occur before any copies into physregs.
+  if (!Stores.empty())
+    Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, &Stores[0],Stores.size());
+
+  static const unsigned IntArgRegs[] = {
+    IA64::out0, IA64::out1, IA64::out2, IA64::out3, 
+    IA64::out4, IA64::out5, IA64::out6, IA64::out7
+  };
+
+  static const unsigned FPArgRegs[] = {
+    IA64::F8,  IA64::F9,  IA64::F10, IA64::F11, 
+    IA64::F12, IA64::F13, IA64::F14, IA64::F15
+  };
+
+  SDOperand InFlag;
+  
+  // save the current GP, SP and RP : FIXME: do we need to do all 3 always?
+  SDOperand GPBeforeCall = DAG.getCopyFromReg(Chain, IA64::r1, MVT::i64, InFlag);
+  Chain = GPBeforeCall.getValue(1);
+  InFlag = Chain.getValue(2);
+  SDOperand SPBeforeCall = DAG.getCopyFromReg(Chain, IA64::r12, MVT::i64, InFlag);
+  Chain = SPBeforeCall.getValue(1);
+  InFlag = Chain.getValue(2);
+  SDOperand RPBeforeCall = DAG.getCopyFromReg(Chain, IA64::rp, MVT::i64, InFlag);
+  Chain = RPBeforeCall.getValue(1);
+  InFlag = Chain.getValue(2);
+
+  // Build a sequence of copy-to-reg nodes chained together with token chain
+  // and flag operands which copy the outgoing integer args into regs out[0-7]
+  // mapped 1:1 and the FP args into regs F8-F15 "lazily"
+  // TODO: for performance, we should only copy FP args into int regs when we
+  // know this is required (i.e. for varardic or external (unknown) functions)
+
+  // first to the FP->(integer representation) conversions, these are
+  // flagged for now, but shouldn't have to be (TODO)
+  unsigned seenConverts = 0;
+  for (unsigned i = 0, e = RegValuesToPass.size(); i != e; ++i) {
+    if(MVT::isFloatingPoint(RegValuesToPass[i].getValueType())) {
+      Chain = DAG.getCopyToReg(Chain, IntArgRegs[i], Converts[seenConverts++], 
+                               InFlag);
+      InFlag = Chain.getValue(1);
+    }
+  }
+
+  // next copy args into the usual places, these are flagged
+  unsigned usedFPArgs = 0;
+  for (unsigned i = 0, e = RegValuesToPass.size(); i != e; ++i) {
+    Chain = DAG.getCopyToReg(Chain,
+      MVT::isInteger(RegValuesToPass[i].getValueType()) ?
+        IntArgRegs[i] : FPArgRegs[usedFPArgs++], RegValuesToPass[i], 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.
+/*
+  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
+    Callee = DAG.getTargetGlobalAddress(G->getGlobal(), MVT::i64);
+  }
+*/
+
+  std::vector<MVT::ValueType> NodeTys;
+  std::vector<SDOperand> CallOperands;
+  NodeTys.push_back(MVT::Other);   // Returns a chain
+  NodeTys.push_back(MVT::Flag);    // Returns a flag for retval copy to use.
+  CallOperands.push_back(Chain);
+  CallOperands.push_back(Callee);
+
+  // emit the call itself
+  if (InFlag.Val)
+    CallOperands.push_back(InFlag);
+  else
+    assert(0 && "this should never happen!\n");
+
+  // to make way for a hack:
+  Chain = DAG.getNode(IA64ISD::BRCALL, NodeTys,
+                      &CallOperands[0], CallOperands.size());
+  InFlag = Chain.getValue(1);
+
+  // restore the GP, SP and RP after the call  
+  Chain = DAG.getCopyToReg(Chain, IA64::r1, GPBeforeCall, InFlag);
+  InFlag = Chain.getValue(1);
+  Chain = DAG.getCopyToReg(Chain, IA64::r12, SPBeforeCall, InFlag);
+  InFlag = Chain.getValue(1);
+  Chain = DAG.getCopyToReg(Chain, IA64::rp, RPBeforeCall, InFlag);
+  InFlag = Chain.getValue(1);
+ 
+  std::vector<MVT::ValueType> RetVals;
+  RetVals.push_back(MVT::Other);
+  RetVals.push_back(MVT::Flag);
+ 
+  MVT::ValueType RetTyVT = getValueType(RetTy);
+  SDOperand RetVal;
+  if (RetTyVT != MVT::isVoid) {
+    switch (RetTyVT) {
+    default: assert(0 && "Unknown value type to return!");
+    case MVT::i1: { // bools are just like other integers (returned in r8)
+      // we *could* fall through to the truncate below, but this saves a
+      // few redundant predicate ops
+      SDOperand boolInR8 = DAG.getCopyFromReg(Chain, IA64::r8, MVT::i64,InFlag);
+      InFlag = boolInR8.getValue(2);
+      Chain = boolInR8.getValue(1);
+      SDOperand zeroReg = DAG.getCopyFromReg(Chain, IA64::r0, MVT::i64, InFlag);
+      InFlag = zeroReg.getValue(2);
+      Chain = zeroReg.getValue(1);
+      
+      RetVal = DAG.getSetCC(MVT::i1, boolInR8, zeroReg, ISD::SETNE);
+      break;
+    }
+    case MVT::i8:
+    case MVT::i16:
+    case MVT::i32:
+      RetVal = DAG.getCopyFromReg(Chain, IA64::r8, MVT::i64, InFlag);
+      Chain = RetVal.getValue(1);
+      
+      // keep track of whether it is sign or zero extended (todo: bools?)
+/* XXX
+      RetVal = DAG.getNode(RetTy->isSigned() ? ISD::AssertSext :ISD::AssertZext,
+                           MVT::i64, RetVal, DAG.getValueType(RetTyVT));
+*/
+      RetVal = DAG.getNode(ISD::TRUNCATE, RetTyVT, RetVal);
+      break;
+    case MVT::i64:
+      RetVal = DAG.getCopyFromReg(Chain, IA64::r8, MVT::i64, InFlag);
+      Chain = RetVal.getValue(1);
+      InFlag = RetVal.getValue(2); // XXX dead
+      break;
+    case MVT::f32:
+      RetVal = DAG.getCopyFromReg(Chain, IA64::F8, MVT::f64, InFlag);
+      Chain = RetVal.getValue(1);
+      RetVal = DAG.getNode(ISD::TRUNCATE, MVT::f32, RetVal);
+      break;
+    case MVT::f64:
+      RetVal = DAG.getCopyFromReg(Chain, IA64::F8, MVT::f64, InFlag);
+      Chain = RetVal.getValue(1);
+      InFlag = RetVal.getValue(2); // XXX dead
+      break;
+    }
+  }
+  
+  Chain = DAG.getNode(ISD::CALLSEQ_END, MVT::Other, Chain,
+                      DAG.getConstant(NumBytes, getPointerTy()));
+  
+  return std::make_pair(RetVal, Chain);
+}
+
+SDOperand IA64TargetLowering::
+LowerOperation(SDOperand Op, SelectionDAG &DAG) {
+  switch (Op.getOpcode()) {
+  default: assert(0 && "Should not custom lower this!");
+  case ISD::GlobalTLSAddress:
+    assert(0 && "TLS not implemented for IA64.");
+  case ISD::RET: {
+    SDOperand AR_PFSVal, Copy;
+    
+    switch(Op.getNumOperands()) {
+     default:
+      assert(0 && "Do not know how to return this many arguments!");
+      abort();
+    case 1: 
+      AR_PFSVal = DAG.getCopyFromReg(Op.getOperand(0), VirtGPR, MVT::i64);
+      AR_PFSVal = DAG.getCopyToReg(AR_PFSVal.getValue(1), IA64::AR_PFS, 
+                                   AR_PFSVal);
+      return DAG.getNode(IA64ISD::RET_FLAG, MVT::Other, AR_PFSVal);
+    case 3: {
+      // Copy the result into the output register & restore ar.pfs
+      MVT::ValueType ArgVT = Op.getOperand(1).getValueType();
+      unsigned ArgReg = MVT::isInteger(ArgVT) ? IA64::r8 : IA64::F8;
+
+      AR_PFSVal = DAG.getCopyFromReg(Op.getOperand(0), VirtGPR, MVT::i64);
+      Copy = DAG.getCopyToReg(AR_PFSVal.getValue(1), ArgReg, Op.getOperand(1),
+                              SDOperand());
+      AR_PFSVal = DAG.getCopyToReg(Copy.getValue(0), IA64::AR_PFS, AR_PFSVal,
+                                   Copy.getValue(1));
+      return DAG.getNode(IA64ISD::RET_FLAG, MVT::Other,
+                         AR_PFSVal, AR_PFSVal.getValue(1));
+    }
+    }
+    return SDOperand();
+  }
+  case ISD::VAARG: {
+    MVT::ValueType VT = getPointerTy();
+    SrcValueSDNode *SV = cast<SrcValueSDNode>(Op.getOperand(2));
+    SDOperand VAList = DAG.getLoad(VT, Op.getOperand(0), Op.getOperand(1), 
+                                   SV->getValue(), SV->getOffset());
+    // Increment the pointer, VAList, to the next vaarg
+    SDOperand VAIncr = DAG.getNode(ISD::ADD, VT, VAList, 
+                                   DAG.getConstant(MVT::getSizeInBits(VT)/8, 
+                                                   VT));
+    // Store the incremented VAList to the legalized pointer
+    VAIncr = DAG.getStore(VAList.getValue(1), VAIncr,
+                          Op.getOperand(1), SV->getValue(), SV->getOffset());
+    // Load the actual argument out of the pointer VAList
+    return DAG.getLoad(Op.getValueType(), VAIncr, VAList, NULL, 0);
+  }
+  case ISD::VASTART: {
+    // vastart just stores the address of the VarArgsFrameIndex slot into the
+    // memory location argument.
+    SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i64);
+    SrcValueSDNode *SV = cast<SrcValueSDNode>(Op.getOperand(2));
+    return DAG.getStore(Op.getOperand(0), FR, 
+                        Op.getOperand(1), SV->getValue(), SV->getOffset());
+  }
+  // Frame & Return address.  Currently unimplemented
+  case ISD::RETURNADDR:         break;
+  case ISD::FRAMEADDR:          break;
+  }
+  return SDOperand();
+}