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/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
new file mode 100644
index 0000000..6c2f383
--- /dev/null
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -0,0 +1,3451 @@
+//===-- PPCISelLowering.cpp - PPC DAG Lowering Implementation -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the PPCISelLowering class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "PPCISelLowering.h"
+#include "PPCMachineFunctionInfo.h"
+#include "PPCPredicates.h"
+#include "PPCTargetMachine.h"
+#include "PPCPerfectShuffle.h"
+#include "llvm/ADT/VectorExtras.h"
+#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include "llvm/CodeGen/CallingConvLower.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"
+#include "llvm/Intrinsics.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/CommandLine.h"
+using namespace llvm;
+
+static cl::opt<bool> EnablePPCPreinc("enable-ppc-preinc", 
+cl::desc("enable preincrement load/store generation on PPC (experimental)"),
+                                     cl::Hidden);
+
+PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
+  : TargetLowering(TM), PPCSubTarget(*TM.getSubtargetImpl()) {
+    
+  setPow2DivIsCheap();
+  
+  // Use _setjmp/_longjmp instead of setjmp/longjmp.
+  setUseUnderscoreSetJmp(true);
+  setUseUnderscoreLongJmp(true);
+    
+  // Set up the register classes.
+  addRegisterClass(MVT::i32, PPC::GPRCRegisterClass);
+  addRegisterClass(MVT::f32, PPC::F4RCRegisterClass);
+  addRegisterClass(MVT::f64, PPC::F8RCRegisterClass);
+  
+  // PowerPC has an i16 but no i8 (or i1) SEXTLOAD
+  setLoadXAction(ISD::SEXTLOAD, MVT::i1, Expand);
+  setLoadXAction(ISD::SEXTLOAD, MVT::i8, Expand);
+  
+  // PowerPC does not have truncstore for i1.
+  setStoreXAction(MVT::i1, Promote);
+
+  // PowerPC has pre-inc load and store's.
+  setIndexedLoadAction(ISD::PRE_INC, MVT::i1, Legal);
+  setIndexedLoadAction(ISD::PRE_INC, MVT::i8, Legal);
+  setIndexedLoadAction(ISD::PRE_INC, MVT::i16, Legal);
+  setIndexedLoadAction(ISD::PRE_INC, MVT::i32, Legal);
+  setIndexedLoadAction(ISD::PRE_INC, MVT::i64, Legal);
+  setIndexedStoreAction(ISD::PRE_INC, MVT::i1, Legal);
+  setIndexedStoreAction(ISD::PRE_INC, MVT::i8, Legal);
+  setIndexedStoreAction(ISD::PRE_INC, MVT::i16, Legal);
+  setIndexedStoreAction(ISD::PRE_INC, MVT::i32, Legal);
+  setIndexedStoreAction(ISD::PRE_INC, MVT::i64, Legal);
+
+  setOperationAction(ISD::ConstantFP, MVT::f64, Expand);
+  setOperationAction(ISD::ConstantFP, MVT::f32, Expand);
+
+  // PowerPC has no intrinsics for these particular operations
+  setOperationAction(ISD::MEMMOVE, MVT::Other, Expand);
+  setOperationAction(ISD::MEMSET, MVT::Other, Expand);
+  setOperationAction(ISD::MEMCPY, MVT::Other, Expand);
+  
+  // PowerPC has no SREM/UREM instructions
+  setOperationAction(ISD::SREM, MVT::i32, Expand);
+  setOperationAction(ISD::UREM, MVT::i32, Expand);
+  setOperationAction(ISD::SREM, MVT::i64, Expand);
+  setOperationAction(ISD::UREM, MVT::i64, Expand);
+  
+  // We don't support sin/cos/sqrt/fmod
+  setOperationAction(ISD::FSIN , MVT::f64, Expand);
+  setOperationAction(ISD::FCOS , MVT::f64, Expand);
+  setOperationAction(ISD::FREM , MVT::f64, Expand);
+  setOperationAction(ISD::FSIN , MVT::f32, Expand);
+  setOperationAction(ISD::FCOS , MVT::f32, Expand);
+  setOperationAction(ISD::FREM , MVT::f32, Expand);
+  
+  // If we're enabling GP optimizations, use hardware square root
+  if (!TM.getSubtarget<PPCSubtarget>().hasFSQRT()) {
+    setOperationAction(ISD::FSQRT, MVT::f64, Expand);
+    setOperationAction(ISD::FSQRT, MVT::f32, Expand);
+  }
+  
+  setOperationAction(ISD::FCOPYSIGN, MVT::f64, Expand);
+  setOperationAction(ISD::FCOPYSIGN, MVT::f32, Expand);
+  
+  // PowerPC does not have BSWAP, CTPOP or CTTZ
+  setOperationAction(ISD::BSWAP, MVT::i32  , Expand);
+  setOperationAction(ISD::CTPOP, MVT::i32  , Expand);
+  setOperationAction(ISD::CTTZ , MVT::i32  , Expand);
+  setOperationAction(ISD::BSWAP, MVT::i64  , Expand);
+  setOperationAction(ISD::CTPOP, MVT::i64  , Expand);
+  setOperationAction(ISD::CTTZ , MVT::i64  , Expand);
+  
+  // PowerPC does not have ROTR
+  setOperationAction(ISD::ROTR, MVT::i32   , Expand);
+  
+  // PowerPC does not have Select
+  setOperationAction(ISD::SELECT, MVT::i32, Expand);
+  setOperationAction(ISD::SELECT, MVT::i64, Expand);
+  setOperationAction(ISD::SELECT, MVT::f32, Expand);
+  setOperationAction(ISD::SELECT, MVT::f64, Expand);
+  
+  // PowerPC wants to turn select_cc of FP into fsel when possible.
+  setOperationAction(ISD::SELECT_CC, MVT::f32, Custom);
+  setOperationAction(ISD::SELECT_CC, MVT::f64, Custom);
+
+  // PowerPC wants to optimize integer setcc a bit
+  setOperationAction(ISD::SETCC, MVT::i32, Custom);
+  
+  // PowerPC does not have BRCOND which requires SetCC
+  setOperationAction(ISD::BRCOND, MVT::Other, Expand);
+
+  setOperationAction(ISD::BR_JT,  MVT::Other, Expand);
+  
+  // PowerPC turns FP_TO_SINT into FCTIWZ and some load/stores.
+  setOperationAction(ISD::FP_TO_SINT, MVT::i32, Custom);
+
+  // PowerPC does not have [U|S]INT_TO_FP
+  setOperationAction(ISD::SINT_TO_FP, MVT::i32, Expand);
+  setOperationAction(ISD::UINT_TO_FP, MVT::i32, Expand);
+
+  setOperationAction(ISD::BIT_CONVERT, MVT::f32, Expand);
+  setOperationAction(ISD::BIT_CONVERT, MVT::i32, Expand);
+  setOperationAction(ISD::BIT_CONVERT, MVT::i64, Expand);
+  setOperationAction(ISD::BIT_CONVERT, MVT::f64, Expand);
+
+  // We cannot sextinreg(i1).  Expand to shifts.
+  setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand);
+
+  // Support label based line numbers.
+  setOperationAction(ISD::LOCATION, MVT::Other, Expand);
+  setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand);
+  if (!TM.getSubtarget<PPCSubtarget>().isDarwin()) {
+    setOperationAction(ISD::LABEL, MVT::Other, Expand);
+  } else {
+    setOperationAction(ISD::EXCEPTIONADDR, MVT::i64, Expand);
+    setOperationAction(ISD::EHSELECTION,   MVT::i64, Expand);
+    setOperationAction(ISD::EXCEPTIONADDR, MVT::i32, Expand);
+    setOperationAction(ISD::EHSELECTION,   MVT::i32, Expand);
+  }
+  
+  // We want to legalize GlobalAddress and ConstantPool nodes into the 
+  // appropriate instructions to materialize the address.
+  setOperationAction(ISD::GlobalAddress, MVT::i32, Custom);
+  setOperationAction(ISD::GlobalTLSAddress, MVT::i32, Custom);
+  setOperationAction(ISD::ConstantPool,  MVT::i32, Custom);
+  setOperationAction(ISD::JumpTable,     MVT::i32, Custom);
+  setOperationAction(ISD::GlobalAddress, MVT::i64, Custom);
+  setOperationAction(ISD::GlobalTLSAddress, MVT::i64, Custom);
+  setOperationAction(ISD::ConstantPool,  MVT::i64, Custom);
+  setOperationAction(ISD::JumpTable,     MVT::i64, Custom);
+  
+  // RET must be custom lowered, to meet ABI requirements
+  setOperationAction(ISD::RET               , MVT::Other, Custom);
+  
+  // VASTART needs to be custom lowered to use the VarArgsFrameIndex
+  setOperationAction(ISD::VASTART           , MVT::Other, Custom);
+  
+  // VAARG is custom lowered with ELF 32 ABI
+  if (TM.getSubtarget<PPCSubtarget>().isELF32_ABI())
+    setOperationAction(ISD::VAARG, MVT::Other, Custom);
+  else
+    setOperationAction(ISD::VAARG, MVT::Other, Expand);
+  
+  // 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, Custom);
+  setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32  , Custom);
+  setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i64  , Custom);
+
+  // We want to custom lower some of our intrinsics.
+  setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);
+  
+  if (TM.getSubtarget<PPCSubtarget>().has64BitSupport()) {
+    // They also have instructions for converting between i64 and fp.
+    setOperationAction(ISD::FP_TO_SINT, MVT::i64, Custom);
+    setOperationAction(ISD::FP_TO_UINT, MVT::i64, Expand);
+    setOperationAction(ISD::SINT_TO_FP, MVT::i64, Custom);
+    setOperationAction(ISD::UINT_TO_FP, MVT::i64, Expand);
+    setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand);
+ 
+    // FIXME: disable this lowered code.  This generates 64-bit register values,
+    // and we don't model the fact that the top part is clobbered by calls.  We
+    // need to flag these together so that the value isn't live across a call.
+    //setOperationAction(ISD::SINT_TO_FP, MVT::i32, Custom);
+    
+    // To take advantage of the above i64 FP_TO_SINT, promote i32 FP_TO_UINT
+    setOperationAction(ISD::FP_TO_UINT, MVT::i32, Promote);
+  } else {
+    // PowerPC does not have FP_TO_UINT on 32-bit implementations.
+    setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand);
+  }
+
+  if (TM.getSubtarget<PPCSubtarget>().use64BitRegs()) {
+    // 64 bit PowerPC implementations can support i64 types directly
+    addRegisterClass(MVT::i64, PPC::G8RCRegisterClass);
+    // BUILD_PAIR can't be handled natively, and should be expanded to shl/or
+    setOperationAction(ISD::BUILD_PAIR, MVT::i64, Expand);
+  } else {
+    // 32 bit PowerPC wants to expand i64 shifts itself.
+    setOperationAction(ISD::SHL_PARTS, MVT::i32, Custom);
+    setOperationAction(ISD::SRA_PARTS, MVT::i32, Custom);
+    setOperationAction(ISD::SRL_PARTS, MVT::i32, Custom);
+  }
+
+  if (TM.getSubtarget<PPCSubtarget>().hasAltivec()) {
+    // First set operation action for all vector types to expand. Then we
+    // will selectively turn on ones that can be effectively codegen'd.
+    for (unsigned VT = (unsigned)MVT::FIRST_VECTOR_VALUETYPE;
+         VT <= (unsigned)MVT::LAST_VECTOR_VALUETYPE; ++VT) {
+      // add/sub are legal for all supported vector VT's.
+      setOperationAction(ISD::ADD , (MVT::ValueType)VT, Legal);
+      setOperationAction(ISD::SUB , (MVT::ValueType)VT, Legal);
+      
+      // We promote all shuffles to v16i8.
+      setOperationAction(ISD::VECTOR_SHUFFLE, (MVT::ValueType)VT, Promote);
+      AddPromotedToType (ISD::VECTOR_SHUFFLE, (MVT::ValueType)VT, MVT::v16i8);
+
+      // We promote all non-typed operations to v4i32.
+      setOperationAction(ISD::AND   , (MVT::ValueType)VT, Promote);
+      AddPromotedToType (ISD::AND   , (MVT::ValueType)VT, MVT::v4i32);
+      setOperationAction(ISD::OR    , (MVT::ValueType)VT, Promote);
+      AddPromotedToType (ISD::OR    , (MVT::ValueType)VT, MVT::v4i32);
+      setOperationAction(ISD::XOR   , (MVT::ValueType)VT, Promote);
+      AddPromotedToType (ISD::XOR   , (MVT::ValueType)VT, MVT::v4i32);
+      setOperationAction(ISD::LOAD  , (MVT::ValueType)VT, Promote);
+      AddPromotedToType (ISD::LOAD  , (MVT::ValueType)VT, MVT::v4i32);
+      setOperationAction(ISD::SELECT, (MVT::ValueType)VT, Promote);
+      AddPromotedToType (ISD::SELECT, (MVT::ValueType)VT, MVT::v4i32);
+      setOperationAction(ISD::STORE, (MVT::ValueType)VT, Promote);
+      AddPromotedToType (ISD::STORE, (MVT::ValueType)VT, MVT::v4i32);
+      
+      // No other operations are legal.
+      setOperationAction(ISD::MUL , (MVT::ValueType)VT, Expand);
+      setOperationAction(ISD::SDIV, (MVT::ValueType)VT, Expand);
+      setOperationAction(ISD::SREM, (MVT::ValueType)VT, Expand);
+      setOperationAction(ISD::UDIV, (MVT::ValueType)VT, Expand);
+      setOperationAction(ISD::UREM, (MVT::ValueType)VT, Expand);
+      setOperationAction(ISD::FDIV, (MVT::ValueType)VT, Expand);
+      setOperationAction(ISD::EXTRACT_VECTOR_ELT, (MVT::ValueType)VT, Expand);
+      setOperationAction(ISD::INSERT_VECTOR_ELT, (MVT::ValueType)VT, Expand);
+      setOperationAction(ISD::BUILD_VECTOR, (MVT::ValueType)VT, Expand);
+
+      setOperationAction(ISD::SCALAR_TO_VECTOR, (MVT::ValueType)VT, Expand);
+    }
+
+    // We can custom expand all VECTOR_SHUFFLEs to VPERM, others we can handle
+    // with merges, splats, etc.
+    setOperationAction(ISD::VECTOR_SHUFFLE, MVT::v16i8, Custom);
+
+    setOperationAction(ISD::AND   , MVT::v4i32, Legal);
+    setOperationAction(ISD::OR    , MVT::v4i32, Legal);
+    setOperationAction(ISD::XOR   , MVT::v4i32, Legal);
+    setOperationAction(ISD::LOAD  , MVT::v4i32, Legal);
+    setOperationAction(ISD::SELECT, MVT::v4i32, Expand);
+    setOperationAction(ISD::STORE , MVT::v4i32, Legal);
+    
+    addRegisterClass(MVT::v4f32, PPC::VRRCRegisterClass);
+    addRegisterClass(MVT::v4i32, PPC::VRRCRegisterClass);
+    addRegisterClass(MVT::v8i16, PPC::VRRCRegisterClass);
+    addRegisterClass(MVT::v16i8, PPC::VRRCRegisterClass);
+    
+    setOperationAction(ISD::MUL, MVT::v4f32, Legal);
+    setOperationAction(ISD::MUL, MVT::v4i32, Custom);
+    setOperationAction(ISD::MUL, MVT::v8i16, Custom);
+    setOperationAction(ISD::MUL, MVT::v16i8, Custom);
+
+    setOperationAction(ISD::SCALAR_TO_VECTOR, MVT::v4f32, Custom);
+    setOperationAction(ISD::SCALAR_TO_VECTOR, MVT::v4i32, Custom);
+    
+    setOperationAction(ISD::BUILD_VECTOR, MVT::v16i8, Custom);
+    setOperationAction(ISD::BUILD_VECTOR, MVT::v8i16, Custom);
+    setOperationAction(ISD::BUILD_VECTOR, MVT::v4i32, Custom);
+    setOperationAction(ISD::BUILD_VECTOR, MVT::v4f32, Custom);
+  }
+  
+  setSetCCResultType(MVT::i32);
+  setShiftAmountType(MVT::i32);
+  setSetCCResultContents(ZeroOrOneSetCCResult);
+  
+  if (TM.getSubtarget<PPCSubtarget>().isPPC64()) {
+    setStackPointerRegisterToSaveRestore(PPC::X1);
+    setExceptionPointerRegister(PPC::X3);
+    setExceptionSelectorRegister(PPC::X4);
+  } else {
+    setStackPointerRegisterToSaveRestore(PPC::R1);
+    setExceptionPointerRegister(PPC::R3);
+    setExceptionSelectorRegister(PPC::R4);
+  }
+  
+  // We have target-specific dag combine patterns for the following nodes:
+  setTargetDAGCombine(ISD::SINT_TO_FP);
+  setTargetDAGCombine(ISD::STORE);
+  setTargetDAGCombine(ISD::BR_CC);
+  setTargetDAGCombine(ISD::BSWAP);
+  
+  computeRegisterProperties();
+}
+
+const char *PPCTargetLowering::getTargetNodeName(unsigned Opcode) const {
+  switch (Opcode) {
+  default: return 0;
+  case PPCISD::FSEL:          return "PPCISD::FSEL";
+  case PPCISD::FCFID:         return "PPCISD::FCFID";
+  case PPCISD::FCTIDZ:        return "PPCISD::FCTIDZ";
+  case PPCISD::FCTIWZ:        return "PPCISD::FCTIWZ";
+  case PPCISD::STFIWX:        return "PPCISD::STFIWX";
+  case PPCISD::VMADDFP:       return "PPCISD::VMADDFP";
+  case PPCISD::VNMSUBFP:      return "PPCISD::VNMSUBFP";
+  case PPCISD::VPERM:         return "PPCISD::VPERM";
+  case PPCISD::Hi:            return "PPCISD::Hi";
+  case PPCISD::Lo:            return "PPCISD::Lo";
+  case PPCISD::DYNALLOC:      return "PPCISD::DYNALLOC";
+  case PPCISD::GlobalBaseReg: return "PPCISD::GlobalBaseReg";
+  case PPCISD::SRL:           return "PPCISD::SRL";
+  case PPCISD::SRA:           return "PPCISD::SRA";
+  case PPCISD::SHL:           return "PPCISD::SHL";
+  case PPCISD::EXTSW_32:      return "PPCISD::EXTSW_32";
+  case PPCISD::STD_32:        return "PPCISD::STD_32";
+  case PPCISD::CALL_ELF:      return "PPCISD::CALL_ELF";
+  case PPCISD::CALL_Macho:    return "PPCISD::CALL_Macho";
+  case PPCISD::MTCTR:         return "PPCISD::MTCTR";
+  case PPCISD::BCTRL_Macho:   return "PPCISD::BCTRL_Macho";
+  case PPCISD::BCTRL_ELF:     return "PPCISD::BCTRL_ELF";
+  case PPCISD::RET_FLAG:      return "PPCISD::RET_FLAG";
+  case PPCISD::MFCR:          return "PPCISD::MFCR";
+  case PPCISD::VCMP:          return "PPCISD::VCMP";
+  case PPCISD::VCMPo:         return "PPCISD::VCMPo";
+  case PPCISD::LBRX:          return "PPCISD::LBRX";
+  case PPCISD::STBRX:         return "PPCISD::STBRX";
+  case PPCISD::COND_BRANCH:   return "PPCISD::COND_BRANCH";
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Node matching predicates, for use by the tblgen matching code.
+//===----------------------------------------------------------------------===//
+
+/// isFloatingPointZero - Return true if this is 0.0 or -0.0.
+static bool isFloatingPointZero(SDOperand Op) {
+  if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(Op))
+    return CFP->isExactlyValue(-0.0) || CFP->isExactlyValue(0.0);
+  else if (ISD::isEXTLoad(Op.Val) || ISD::isNON_EXTLoad(Op.Val)) {
+    // Maybe this has already been legalized into the constant pool?
+    if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op.getOperand(1)))
+      if (ConstantFP *CFP = dyn_cast<ConstantFP>(CP->getConstVal()))
+        return CFP->isExactlyValue(-0.0) || CFP->isExactlyValue(0.0);
+  }
+  return false;
+}
+
+/// isConstantOrUndef - Op is either an undef node or a ConstantSDNode.  Return
+/// true if Op is undef or if it matches the specified value.
+static bool isConstantOrUndef(SDOperand Op, unsigned Val) {
+  return Op.getOpcode() == ISD::UNDEF || 
+         cast<ConstantSDNode>(Op)->getValue() == Val;
+}
+
+/// isVPKUHUMShuffleMask - Return true if this is the shuffle mask for a
+/// VPKUHUM instruction.
+bool PPC::isVPKUHUMShuffleMask(SDNode *N, bool isUnary) {
+  if (!isUnary) {
+    for (unsigned i = 0; i != 16; ++i)
+      if (!isConstantOrUndef(N->getOperand(i),  i*2+1))
+        return false;
+  } else {
+    for (unsigned i = 0; i != 8; ++i)
+      if (!isConstantOrUndef(N->getOperand(i),  i*2+1) ||
+          !isConstantOrUndef(N->getOperand(i+8),  i*2+1))
+        return false;
+  }
+  return true;
+}
+
+/// isVPKUWUMShuffleMask - Return true if this is the shuffle mask for a
+/// VPKUWUM instruction.
+bool PPC::isVPKUWUMShuffleMask(SDNode *N, bool isUnary) {
+  if (!isUnary) {
+    for (unsigned i = 0; i != 16; i += 2)
+      if (!isConstantOrUndef(N->getOperand(i  ),  i*2+2) ||
+          !isConstantOrUndef(N->getOperand(i+1),  i*2+3))
+        return false;
+  } else {
+    for (unsigned i = 0; i != 8; i += 2)
+      if (!isConstantOrUndef(N->getOperand(i  ),  i*2+2) ||
+          !isConstantOrUndef(N->getOperand(i+1),  i*2+3) ||
+          !isConstantOrUndef(N->getOperand(i+8),  i*2+2) ||
+          !isConstantOrUndef(N->getOperand(i+9),  i*2+3))
+        return false;
+  }
+  return true;
+}
+
+/// isVMerge - Common function, used to match vmrg* shuffles.
+///
+static bool isVMerge(SDNode *N, unsigned UnitSize, 
+                     unsigned LHSStart, unsigned RHSStart) {
+  assert(N->getOpcode() == ISD::BUILD_VECTOR &&
+         N->getNumOperands() == 16 && "PPC only supports shuffles by bytes!");
+  assert((UnitSize == 1 || UnitSize == 2 || UnitSize == 4) &&
+         "Unsupported merge size!");
+  
+  for (unsigned i = 0; i != 8/UnitSize; ++i)     // Step over units
+    for (unsigned j = 0; j != UnitSize; ++j) {   // Step over bytes within unit
+      if (!isConstantOrUndef(N->getOperand(i*UnitSize*2+j),
+                             LHSStart+j+i*UnitSize) ||
+          !isConstantOrUndef(N->getOperand(i*UnitSize*2+UnitSize+j),
+                             RHSStart+j+i*UnitSize))
+        return false;
+    }
+      return true;
+}
+
+/// isVMRGLShuffleMask - Return true if this is a shuffle mask suitable for
+/// a VRGL* instruction with the specified unit size (1,2 or 4 bytes).
+bool PPC::isVMRGLShuffleMask(SDNode *N, unsigned UnitSize, bool isUnary) {
+  if (!isUnary)
+    return isVMerge(N, UnitSize, 8, 24);
+  return isVMerge(N, UnitSize, 8, 8);
+}
+
+/// isVMRGHShuffleMask - Return true if this is a shuffle mask suitable for
+/// a VRGH* instruction with the specified unit size (1,2 or 4 bytes).
+bool PPC::isVMRGHShuffleMask(SDNode *N, unsigned UnitSize, bool isUnary) {
+  if (!isUnary)
+    return isVMerge(N, UnitSize, 0, 16);
+  return isVMerge(N, UnitSize, 0, 0);
+}
+
+
+/// isVSLDOIShuffleMask - If this is a vsldoi shuffle mask, return the shift
+/// amount, otherwise return -1.
+int PPC::isVSLDOIShuffleMask(SDNode *N, bool isUnary) {
+  assert(N->getOpcode() == ISD::BUILD_VECTOR &&
+         N->getNumOperands() == 16 && "PPC only supports shuffles by bytes!");
+  // Find the first non-undef value in the shuffle mask.
+  unsigned i;
+  for (i = 0; i != 16 && N->getOperand(i).getOpcode() == ISD::UNDEF; ++i)
+    /*search*/;
+  
+  if (i == 16) return -1;  // all undef.
+  
+  // Otherwise, check to see if the rest of the elements are consequtively
+  // numbered from this value.
+  unsigned ShiftAmt = cast<ConstantSDNode>(N->getOperand(i))->getValue();
+  if (ShiftAmt < i) return -1;
+  ShiftAmt -= i;
+
+  if (!isUnary) {
+    // Check the rest of the elements to see if they are consequtive.
+    for (++i; i != 16; ++i)
+      if (!isConstantOrUndef(N->getOperand(i), ShiftAmt+i))
+        return -1;
+  } else {
+    // Check the rest of the elements to see if they are consequtive.
+    for (++i; i != 16; ++i)
+      if (!isConstantOrUndef(N->getOperand(i), (ShiftAmt+i) & 15))
+        return -1;
+  }
+  
+  return ShiftAmt;
+}
+
+/// isSplatShuffleMask - Return true if the specified VECTOR_SHUFFLE operand
+/// specifies a splat of a single element that is suitable for input to
+/// VSPLTB/VSPLTH/VSPLTW.
+bool PPC::isSplatShuffleMask(SDNode *N, unsigned EltSize) {
+  assert(N->getOpcode() == ISD::BUILD_VECTOR &&
+         N->getNumOperands() == 16 &&
+         (EltSize == 1 || EltSize == 2 || EltSize == 4));
+  
+  // This is a splat operation if each element of the permute is the same, and
+  // if the value doesn't reference the second vector.
+  unsigned ElementBase = 0;
+  SDOperand Elt = N->getOperand(0);
+  if (ConstantSDNode *EltV = dyn_cast<ConstantSDNode>(Elt))
+    ElementBase = EltV->getValue();
+  else
+    return false;   // FIXME: Handle UNDEF elements too!
+
+  if (cast<ConstantSDNode>(Elt)->getValue() >= 16)
+    return false;
+  
+  // Check that they are consequtive.
+  for (unsigned i = 1; i != EltSize; ++i) {
+    if (!isa<ConstantSDNode>(N->getOperand(i)) ||
+        cast<ConstantSDNode>(N->getOperand(i))->getValue() != i+ElementBase)
+      return false;
+  }
+  
+  assert(isa<ConstantSDNode>(Elt) && "Invalid VECTOR_SHUFFLE mask!");
+  for (unsigned i = EltSize, e = 16; i != e; i += EltSize) {
+    if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue;
+    assert(isa<ConstantSDNode>(N->getOperand(i)) &&
+           "Invalid VECTOR_SHUFFLE mask!");
+    for (unsigned j = 0; j != EltSize; ++j)
+      if (N->getOperand(i+j) != N->getOperand(j))
+        return false;
+  }
+
+  return true;
+}
+
+/// getVSPLTImmediate - Return the appropriate VSPLT* immediate to splat the
+/// specified isSplatShuffleMask VECTOR_SHUFFLE mask.
+unsigned PPC::getVSPLTImmediate(SDNode *N, unsigned EltSize) {
+  assert(isSplatShuffleMask(N, EltSize));
+  return cast<ConstantSDNode>(N->getOperand(0))->getValue() / EltSize;
+}
+
+/// get_VSPLTI_elt - If this is a build_vector of constants which can be formed
+/// by using a vspltis[bhw] instruction of the specified element size, return
+/// the constant being splatted.  The ByteSize field indicates the number of
+/// bytes of each element [124] -> [bhw].
+SDOperand PPC::get_VSPLTI_elt(SDNode *N, unsigned ByteSize, SelectionDAG &DAG) {
+  SDOperand OpVal(0, 0);
+
+  // If ByteSize of the splat is bigger than the element size of the
+  // build_vector, then we have a case where we are checking for a splat where
+  // multiple elements of the buildvector are folded together into a single
+  // logical element of the splat (e.g. "vsplish 1" to splat {0,1}*8).
+  unsigned EltSize = 16/N->getNumOperands();
+  if (EltSize < ByteSize) {
+    unsigned Multiple = ByteSize/EltSize;   // Number of BV entries per spltval.
+    SDOperand UniquedVals[4];
+    assert(Multiple > 1 && Multiple <= 4 && "How can this happen?");
+    
+    // See if all of the elements in the buildvector agree across.
+    for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
+      if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue;
+      // If the element isn't a constant, bail fully out.
+      if (!isa<ConstantSDNode>(N->getOperand(i))) return SDOperand();
+
+          
+      if (UniquedVals[i&(Multiple-1)].Val == 0)
+        UniquedVals[i&(Multiple-1)] = N->getOperand(i);
+      else if (UniquedVals[i&(Multiple-1)] != N->getOperand(i))
+        return SDOperand();  // no match.
+    }
+    
+    // Okay, if we reached this point, UniquedVals[0..Multiple-1] contains
+    // either constant or undef values that are identical for each chunk.  See
+    // if these chunks can form into a larger vspltis*.
+    
+    // Check to see if all of the leading entries are either 0 or -1.  If
+    // neither, then this won't fit into the immediate field.
+    bool LeadingZero = true;
+    bool LeadingOnes = true;
+    for (unsigned i = 0; i != Multiple-1; ++i) {
+      if (UniquedVals[i].Val == 0) continue;  // Must have been undefs.
+      
+      LeadingZero &= cast<ConstantSDNode>(UniquedVals[i])->isNullValue();
+      LeadingOnes &= cast<ConstantSDNode>(UniquedVals[i])->isAllOnesValue();
+    }
+    // Finally, check the least significant entry.
+    if (LeadingZero) {
+      if (UniquedVals[Multiple-1].Val == 0)
+        return DAG.getTargetConstant(0, MVT::i32);  // 0,0,0,undef
+      int Val = cast<ConstantSDNode>(UniquedVals[Multiple-1])->getValue();
+      if (Val < 16)
+        return DAG.getTargetConstant(Val, MVT::i32);  // 0,0,0,4 -> vspltisw(4)
+    }
+    if (LeadingOnes) {
+      if (UniquedVals[Multiple-1].Val == 0)
+        return DAG.getTargetConstant(~0U, MVT::i32);  // -1,-1,-1,undef
+      int Val =cast<ConstantSDNode>(UniquedVals[Multiple-1])->getSignExtended();
+      if (Val >= -16)                            // -1,-1,-1,-2 -> vspltisw(-2)
+        return DAG.getTargetConstant(Val, MVT::i32);
+    }
+    
+    return SDOperand();
+  }
+  
+  // Check to see if this buildvec has a single non-undef value in its elements.
+  for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
+    if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue;
+    if (OpVal.Val == 0)
+      OpVal = N->getOperand(i);
+    else if (OpVal != N->getOperand(i))
+      return SDOperand();
+  }
+  
+  if (OpVal.Val == 0) return SDOperand();  // All UNDEF: use implicit def.
+  
+  unsigned ValSizeInBytes = 0;
+  uint64_t Value = 0;
+  if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(OpVal)) {
+    Value = CN->getValue();
+    ValSizeInBytes = MVT::getSizeInBits(CN->getValueType(0))/8;
+  } else if (ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(OpVal)) {
+    assert(CN->getValueType(0) == MVT::f32 && "Only one legal FP vector type!");
+    Value = FloatToBits(CN->getValue());
+    ValSizeInBytes = 4;
+  }
+
+  // If the splat value is larger than the element value, then we can never do
+  // this splat.  The only case that we could fit the replicated bits into our
+  // immediate field for would be zero, and we prefer to use vxor for it.
+  if (ValSizeInBytes < ByteSize) return SDOperand();
+  
+  // If the element value is larger than the splat value, cut it in half and
+  // check to see if the two halves are equal.  Continue doing this until we
+  // get to ByteSize.  This allows us to handle 0x01010101 as 0x01.
+  while (ValSizeInBytes > ByteSize) {
+    ValSizeInBytes >>= 1;
+    
+    // If the top half equals the bottom half, we're still ok.
+    if (((Value >> (ValSizeInBytes*8)) & ((1 << (8*ValSizeInBytes))-1)) !=
+         (Value                        & ((1 << (8*ValSizeInBytes))-1)))
+      return SDOperand();
+  }
+
+  // Properly sign extend the value.
+  int ShAmt = (4-ByteSize)*8;
+  int MaskVal = ((int)Value << ShAmt) >> ShAmt;
+  
+  // If this is zero, don't match, zero matches ISD::isBuildVectorAllZeros.
+  if (MaskVal == 0) return SDOperand();
+
+  // Finally, if this value fits in a 5 bit sext field, return it
+  if (((MaskVal << (32-5)) >> (32-5)) == MaskVal)
+    return DAG.getTargetConstant(MaskVal, MVT::i32);
+  return SDOperand();
+}
+
+//===----------------------------------------------------------------------===//
+//  Addressing Mode Selection
+//===----------------------------------------------------------------------===//
+
+/// isIntS16Immediate - This method tests to see if the node is either a 32-bit
+/// or 64-bit immediate, and if the value can be accurately represented as a
+/// sign extension from a 16-bit value.  If so, this returns true and the
+/// immediate.
+static bool isIntS16Immediate(SDNode *N, short &Imm) {
+  if (N->getOpcode() != ISD::Constant)
+    return false;
+  
+  Imm = (short)cast<ConstantSDNode>(N)->getValue();
+  if (N->getValueType(0) == MVT::i32)
+    return Imm == (int32_t)cast<ConstantSDNode>(N)->getValue();
+  else
+    return Imm == (int64_t)cast<ConstantSDNode>(N)->getValue();
+}
+static bool isIntS16Immediate(SDOperand Op, short &Imm) {
+  return isIntS16Immediate(Op.Val, Imm);
+}
+
+
+/// SelectAddressRegReg - Given the specified addressed, check to see if it
+/// can be represented as an indexed [r+r] operation.  Returns false if it
+/// can be more efficiently represented with [r+imm].
+bool PPCTargetLowering::SelectAddressRegReg(SDOperand N, SDOperand &Base,
+                                            SDOperand &Index,
+                                            SelectionDAG &DAG) {
+  short imm = 0;
+  if (N.getOpcode() == ISD::ADD) {
+    if (isIntS16Immediate(N.getOperand(1), imm))
+      return false;    // r+i
+    if (N.getOperand(1).getOpcode() == PPCISD::Lo)
+      return false;    // r+i
+    
+    Base = N.getOperand(0);
+    Index = N.getOperand(1);
+    return true;
+  } else if (N.getOpcode() == ISD::OR) {
+    if (isIntS16Immediate(N.getOperand(1), imm))
+      return false;    // r+i can fold it if we can.
+    
+    // If this is an or of disjoint bitfields, we can codegen this as an add
+    // (for better address arithmetic) if the LHS and RHS of the OR are provably
+    // disjoint.
+    uint64_t LHSKnownZero, LHSKnownOne;
+    uint64_t RHSKnownZero, RHSKnownOne;
+    DAG.ComputeMaskedBits(N.getOperand(0), ~0U, LHSKnownZero, LHSKnownOne);
+    
+    if (LHSKnownZero) {
+      DAG.ComputeMaskedBits(N.getOperand(1), ~0U, RHSKnownZero, RHSKnownOne);
+      // If all of the bits are known zero on the LHS or RHS, the add won't
+      // carry.
+      if ((LHSKnownZero | RHSKnownZero) == ~0U) {
+        Base = N.getOperand(0);
+        Index = N.getOperand(1);
+        return true;
+      }
+    }
+  }
+  
+  return false;
+}
+
+/// Returns true if the address N can be represented by a base register plus
+/// a signed 16-bit displacement [r+imm], and if it is not better
+/// represented as reg+reg.
+bool PPCTargetLowering::SelectAddressRegImm(SDOperand N, SDOperand &Disp,
+                                            SDOperand &Base, SelectionDAG &DAG){
+  // If this can be more profitably realized as r+r, fail.
+  if (SelectAddressRegReg(N, Disp, Base, DAG))
+    return false;
+  
+  if (N.getOpcode() == ISD::ADD) {
+    short imm = 0;
+    if (isIntS16Immediate(N.getOperand(1), imm)) {
+      Disp = DAG.getTargetConstant((int)imm & 0xFFFF, MVT::i32);
+      if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(N.getOperand(0))) {
+        Base = DAG.getTargetFrameIndex(FI->getIndex(), N.getValueType());
+      } else {
+        Base = N.getOperand(0);
+      }
+      return true; // [r+i]
+    } else if (N.getOperand(1).getOpcode() == PPCISD::Lo) {
+      // Match LOAD (ADD (X, Lo(G))).
+      assert(!cast<ConstantSDNode>(N.getOperand(1).getOperand(1))->getValue()
+             && "Cannot handle constant offsets yet!");
+      Disp = N.getOperand(1).getOperand(0);  // The global address.
+      assert(Disp.getOpcode() == ISD::TargetGlobalAddress ||
+             Disp.getOpcode() == ISD::TargetConstantPool ||
+             Disp.getOpcode() == ISD::TargetJumpTable);
+      Base = N.getOperand(0);
+      return true;  // [&g+r]
+    }
+  } else if (N.getOpcode() == ISD::OR) {
+    short imm = 0;
+    if (isIntS16Immediate(N.getOperand(1), imm)) {
+      // If this is an or of disjoint bitfields, we can codegen this as an add
+      // (for better address arithmetic) if the LHS and RHS of the OR are
+      // provably disjoint.
+      uint64_t LHSKnownZero, LHSKnownOne;
+      DAG.ComputeMaskedBits(N.getOperand(0), ~0U, LHSKnownZero, LHSKnownOne);
+      if ((LHSKnownZero|~(unsigned)imm) == ~0U) {
+        // If all of the bits are known zero on the LHS or RHS, the add won't
+        // carry.
+        Base = N.getOperand(0);
+        Disp = DAG.getTargetConstant((int)imm & 0xFFFF, MVT::i32);
+        return true;
+      }
+    }
+  } else if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N)) {
+    // Loading from a constant address.
+    
+    // If this address fits entirely in a 16-bit sext immediate field, codegen
+    // this as "d, 0"
+    short Imm;
+    if (isIntS16Immediate(CN, Imm)) {
+      Disp = DAG.getTargetConstant(Imm, CN->getValueType(0));
+      Base = DAG.getRegister(PPC::R0, CN->getValueType(0));
+      return true;
+    }
+
+    // Handle 32-bit sext immediates with LIS + addr mode.
+    if (CN->getValueType(0) == MVT::i32 ||
+        (int64_t)CN->getValue() == (int)CN->getValue()) {
+      int Addr = (int)CN->getValue();
+      
+      // Otherwise, break this down into an LIS + disp.
+      Disp = DAG.getTargetConstant((short)Addr, MVT::i32);
+      
+      Base = DAG.getTargetConstant((Addr - (signed short)Addr) >> 16, MVT::i32);
+      unsigned Opc = CN->getValueType(0) == MVT::i32 ? PPC::LIS : PPC::LIS8;
+      Base = SDOperand(DAG.getTargetNode(Opc, CN->getValueType(0), Base), 0);
+      return true;
+    }
+  }
+  
+  Disp = DAG.getTargetConstant(0, getPointerTy());
+  if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(N))
+    Base = DAG.getTargetFrameIndex(FI->getIndex(), N.getValueType());
+  else
+    Base = N;
+  return true;      // [r+0]
+}
+
+/// SelectAddressRegRegOnly - Given the specified addressed, force it to be
+/// represented as an indexed [r+r] operation.
+bool PPCTargetLowering::SelectAddressRegRegOnly(SDOperand N, SDOperand &Base,
+                                                SDOperand &Index,
+                                                SelectionDAG &DAG) {
+  // Check to see if we can easily represent this as an [r+r] address.  This
+  // will fail if it thinks that the address is more profitably represented as
+  // reg+imm, e.g. where imm = 0.
+  if (SelectAddressRegReg(N, Base, Index, DAG))
+    return true;
+  
+  // If the operand is an addition, always emit this as [r+r], since this is
+  // better (for code size, and execution, as the memop does the add for free)
+  // than emitting an explicit add.
+  if (N.getOpcode() == ISD::ADD) {
+    Base = N.getOperand(0);
+    Index = N.getOperand(1);
+    return true;
+  }
+  
+  // Otherwise, do it the hard way, using R0 as the base register.
+  Base = DAG.getRegister(PPC::R0, N.getValueType());
+  Index = N;
+  return true;
+}
+
+/// SelectAddressRegImmShift - Returns true if the address N can be
+/// represented by a base register plus a signed 14-bit displacement
+/// [r+imm*4].  Suitable for use by STD and friends.
+bool PPCTargetLowering::SelectAddressRegImmShift(SDOperand N, SDOperand &Disp,
+                                                 SDOperand &Base,
+                                                 SelectionDAG &DAG) {
+  // If this can be more profitably realized as r+r, fail.
+  if (SelectAddressRegReg(N, Disp, Base, DAG))
+    return false;
+  
+  if (N.getOpcode() == ISD::ADD) {
+    short imm = 0;
+    if (isIntS16Immediate(N.getOperand(1), imm) && (imm & 3) == 0) {
+      Disp =  DAG.getTargetConstant(((int)imm & 0xFFFF) >> 2, MVT::i32);
+      if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(N.getOperand(0))) {
+        Base = DAG.getTargetFrameIndex(FI->getIndex(), N.getValueType());
+      } else {
+        Base = N.getOperand(0);
+      }
+      return true; // [r+i]
+    } else if (N.getOperand(1).getOpcode() == PPCISD::Lo) {
+      // Match LOAD (ADD (X, Lo(G))).
+      assert(!cast<ConstantSDNode>(N.getOperand(1).getOperand(1))->getValue()
+             && "Cannot handle constant offsets yet!");
+      Disp = N.getOperand(1).getOperand(0);  // The global address.
+      assert(Disp.getOpcode() == ISD::TargetGlobalAddress ||
+             Disp.getOpcode() == ISD::TargetConstantPool ||
+             Disp.getOpcode() == ISD::TargetJumpTable);
+      Base = N.getOperand(0);
+      return true;  // [&g+r]
+    }
+  } else if (N.getOpcode() == ISD::OR) {
+    short imm = 0;
+    if (isIntS16Immediate(N.getOperand(1), imm) && (imm & 3) == 0) {
+      // If this is an or of disjoint bitfields, we can codegen this as an add
+      // (for better address arithmetic) if the LHS and RHS of the OR are
+      // provably disjoint.
+      uint64_t LHSKnownZero, LHSKnownOne;
+      DAG.ComputeMaskedBits(N.getOperand(0), ~0U, LHSKnownZero, LHSKnownOne);
+      if ((LHSKnownZero|~(unsigned)imm) == ~0U) {
+        // If all of the bits are known zero on the LHS or RHS, the add won't
+        // carry.
+        Base = N.getOperand(0);
+        Disp = DAG.getTargetConstant(((int)imm & 0xFFFF) >> 2, MVT::i32);
+        return true;
+      }
+    }
+  } else if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N)) {
+    // Loading from a constant address.  Verify low two bits are clear.
+    if ((CN->getValue() & 3) == 0) {
+      // If this address fits entirely in a 14-bit sext immediate field, codegen
+      // this as "d, 0"
+      short Imm;
+      if (isIntS16Immediate(CN, Imm)) {
+        Disp = DAG.getTargetConstant((unsigned short)Imm >> 2, getPointerTy());
+        Base = DAG.getRegister(PPC::R0, CN->getValueType(0));
+        return true;
+      }
+    
+      // Fold the low-part of 32-bit absolute addresses into addr mode.
+      if (CN->getValueType(0) == MVT::i32 ||
+          (int64_t)CN->getValue() == (int)CN->getValue()) {
+        int Addr = (int)CN->getValue();
+      
+        // Otherwise, break this down into an LIS + disp.
+        Disp = DAG.getTargetConstant((short)Addr >> 2, MVT::i32);
+        
+        Base = DAG.getTargetConstant((Addr-(signed short)Addr) >> 16, MVT::i32);
+        unsigned Opc = CN->getValueType(0) == MVT::i32 ? PPC::LIS : PPC::LIS8;
+        Base = SDOperand(DAG.getTargetNode(Opc, CN->getValueType(0), Base), 0);
+        return true;
+      }
+    }
+  }
+  
+  Disp = DAG.getTargetConstant(0, getPointerTy());
+  if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(N))
+    Base = DAG.getTargetFrameIndex(FI->getIndex(), N.getValueType());
+  else
+    Base = N;
+  return true;      // [r+0]
+}
+
+
+/// getPreIndexedAddressParts - returns true by value, base pointer and
+/// offset pointer and addressing mode by reference if the node's address
+/// can be legally represented as pre-indexed load / store address.
+bool PPCTargetLowering::getPreIndexedAddressParts(SDNode *N, SDOperand &Base,
+                                                  SDOperand &Offset,
+                                                  ISD::MemIndexedMode &AM,
+                                                  SelectionDAG &DAG) {
+  // Disabled by default for now.
+  if (!EnablePPCPreinc) return false;
+  
+  SDOperand Ptr;
+  MVT::ValueType VT;
+  if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
+    Ptr = LD->getBasePtr();
+    VT = LD->getLoadedVT();
+    
+  } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
+    ST = ST;
+    Ptr = ST->getBasePtr();
+    VT  = ST->getStoredVT();
+  } else
+    return false;
+
+  // PowerPC doesn't have preinc load/store instructions for vectors.
+  if (MVT::isVector(VT))
+    return false;
+  
+  // TODO: Check reg+reg first.
+  
+  // LDU/STU use reg+imm*4, others use reg+imm.
+  if (VT != MVT::i64) {
+    // reg + imm
+    if (!SelectAddressRegImm(Ptr, Offset, Base, DAG))
+      return false;
+  } else {
+    // reg + imm * 4.
+    if (!SelectAddressRegImmShift(Ptr, Offset, Base, DAG))
+      return false;
+  }
+
+  if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
+    // PPC64 doesn't have lwau, but it does have lwaux.  Reject preinc load of
+    // sext i32 to i64 when addr mode is r+i.
+    if (LD->getValueType(0) == MVT::i64 && LD->getLoadedVT() == MVT::i32 &&
+        LD->getExtensionType() == ISD::SEXTLOAD &&
+        isa<ConstantSDNode>(Offset))
+      return false;
+  }    
+  
+  AM = ISD::PRE_INC;
+  return true;
+}
+
+//===----------------------------------------------------------------------===//
+//  LowerOperation implementation
+//===----------------------------------------------------------------------===//
+
+static SDOperand LowerConstantPool(SDOperand Op, SelectionDAG &DAG) {
+  MVT::ValueType PtrVT = Op.getValueType();
+  ConstantPoolSDNode *CP = cast<ConstantPoolSDNode>(Op);
+  Constant *C = CP->getConstVal();
+  SDOperand CPI = DAG.getTargetConstantPool(C, PtrVT, CP->getAlignment());
+  SDOperand Zero = DAG.getConstant(0, PtrVT);
+
+  const TargetMachine &TM = DAG.getTarget();
+  
+  SDOperand Hi = DAG.getNode(PPCISD::Hi, PtrVT, CPI, Zero);
+  SDOperand Lo = DAG.getNode(PPCISD::Lo, PtrVT, CPI, Zero);
+
+  // If this is a non-darwin platform, we don't support non-static relo models
+  // yet.
+  if (TM.getRelocationModel() == Reloc::Static ||
+      !TM.getSubtarget<PPCSubtarget>().isDarwin()) {
+    // Generate non-pic code that has direct accesses to the constant pool.
+    // The address of the global is just (hi(&g)+lo(&g)).
+    return DAG.getNode(ISD::ADD, PtrVT, Hi, Lo);
+  }
+  
+  if (TM.getRelocationModel() == Reloc::PIC_) {
+    // With PIC, the first instruction is actually "GR+hi(&G)".
+    Hi = DAG.getNode(ISD::ADD, PtrVT,
+                     DAG.getNode(PPCISD::GlobalBaseReg, PtrVT), Hi);
+  }
+  
+  Lo = DAG.getNode(ISD::ADD, PtrVT, Hi, Lo);
+  return Lo;
+}
+
+static SDOperand LowerJumpTable(SDOperand Op, SelectionDAG &DAG) {
+  MVT::ValueType PtrVT = Op.getValueType();
+  JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
+  SDOperand JTI = DAG.getTargetJumpTable(JT->getIndex(), PtrVT);
+  SDOperand Zero = DAG.getConstant(0, PtrVT);
+  
+  const TargetMachine &TM = DAG.getTarget();
+
+  SDOperand Hi = DAG.getNode(PPCISD::Hi, PtrVT, JTI, Zero);
+  SDOperand Lo = DAG.getNode(PPCISD::Lo, PtrVT, JTI, Zero);
+
+  // If this is a non-darwin platform, we don't support non-static relo models
+  // yet.
+  if (TM.getRelocationModel() == Reloc::Static ||
+      !TM.getSubtarget<PPCSubtarget>().isDarwin()) {
+    // Generate non-pic code that has direct accesses to the constant pool.
+    // The address of the global is just (hi(&g)+lo(&g)).
+    return DAG.getNode(ISD::ADD, PtrVT, Hi, Lo);
+  }
+  
+  if (TM.getRelocationModel() == Reloc::PIC_) {
+    // With PIC, the first instruction is actually "GR+hi(&G)".
+    Hi = DAG.getNode(ISD::ADD, PtrVT,
+                     DAG.getNode(PPCISD::GlobalBaseReg, PtrVT), Hi);
+  }
+  
+  Lo = DAG.getNode(ISD::ADD, PtrVT, Hi, Lo);
+  return Lo;
+}
+
+static SDOperand LowerGlobalTLSAddress(SDOperand Op, SelectionDAG &DAG) {
+  assert(0 && "TLS not implemented for PPC.");
+}
+
+static SDOperand LowerGlobalAddress(SDOperand Op, SelectionDAG &DAG) {
+  MVT::ValueType PtrVT = Op.getValueType();
+  GlobalAddressSDNode *GSDN = cast<GlobalAddressSDNode>(Op);
+  GlobalValue *GV = GSDN->getGlobal();
+  SDOperand GA = DAG.getTargetGlobalAddress(GV, PtrVT, GSDN->getOffset());
+  SDOperand Zero = DAG.getConstant(0, PtrVT);
+  
+  const TargetMachine &TM = DAG.getTarget();
+
+  SDOperand Hi = DAG.getNode(PPCISD::Hi, PtrVT, GA, Zero);
+  SDOperand Lo = DAG.getNode(PPCISD::Lo, PtrVT, GA, Zero);
+
+  // If this is a non-darwin platform, we don't support non-static relo models
+  // yet.
+  if (TM.getRelocationModel() == Reloc::Static ||
+      !TM.getSubtarget<PPCSubtarget>().isDarwin()) {
+    // Generate non-pic code that has direct accesses to globals.
+    // The address of the global is just (hi(&g)+lo(&g)).
+    return DAG.getNode(ISD::ADD, PtrVT, Hi, Lo);
+  }
+  
+  if (TM.getRelocationModel() == Reloc::PIC_) {
+    // With PIC, the first instruction is actually "GR+hi(&G)".
+    Hi = DAG.getNode(ISD::ADD, PtrVT,
+                     DAG.getNode(PPCISD::GlobalBaseReg, PtrVT), Hi);
+  }
+  
+  Lo = DAG.getNode(ISD::ADD, PtrVT, Hi, Lo);
+  
+  if (!TM.getSubtarget<PPCSubtarget>().hasLazyResolverStub(GV))
+    return Lo;
+  
+  // If the global is weak or external, we have to go through the lazy
+  // resolution stub.
+  return DAG.getLoad(PtrVT, DAG.getEntryNode(), Lo, NULL, 0);
+}
+
+static SDOperand LowerSETCC(SDOperand Op, SelectionDAG &DAG) {
+  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
+  
+  // If we're comparing for equality to zero, expose the fact that this is
+  // implented as a ctlz/srl pair on ppc, so that the dag combiner can
+  // fold the new nodes.
+  if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
+    if (C->isNullValue() && CC == ISD::SETEQ) {
+      MVT::ValueType VT = Op.getOperand(0).getValueType();
+      SDOperand Zext = Op.getOperand(0);
+      if (VT < MVT::i32) {
+        VT = MVT::i32;
+        Zext = DAG.getNode(ISD::ZERO_EXTEND, VT, Op.getOperand(0));
+      } 
+      unsigned Log2b = Log2_32(MVT::getSizeInBits(VT));
+      SDOperand Clz = DAG.getNode(ISD::CTLZ, VT, Zext);
+      SDOperand Scc = DAG.getNode(ISD::SRL, VT, Clz,
+                                  DAG.getConstant(Log2b, MVT::i32));
+      return DAG.getNode(ISD::TRUNCATE, MVT::i32, Scc);
+    }
+    // Leave comparisons against 0 and -1 alone for now, since they're usually 
+    // optimized.  FIXME: revisit this when we can custom lower all setcc
+    // optimizations.
+    if (C->isAllOnesValue() || C->isNullValue())
+      return SDOperand();
+  }
+  
+  // If we have an integer seteq/setne, turn it into a compare against zero
+  // by xor'ing the rhs with the lhs, which is faster than setting a
+  // condition register, reading it back out, and masking the correct bit.  The
+  // normal approach here uses sub to do this instead of xor.  Using xor exposes
+  // the result to other bit-twiddling opportunities.
+  MVT::ValueType LHSVT = Op.getOperand(0).getValueType();
+  if (MVT::isInteger(LHSVT) && (CC == ISD::SETEQ || CC == ISD::SETNE)) {
+    MVT::ValueType VT = Op.getValueType();
+    SDOperand Sub = DAG.getNode(ISD::XOR, LHSVT, Op.getOperand(0), 
+                                Op.getOperand(1));
+    return DAG.getSetCC(VT, Sub, DAG.getConstant(0, LHSVT), CC);
+  }
+  return SDOperand();
+}
+
+static SDOperand LowerVAARG(SDOperand Op, SelectionDAG &DAG,
+                              int VarArgsFrameIndex,
+                              int VarArgsStackOffset,
+                              unsigned VarArgsNumGPR,
+                              unsigned VarArgsNumFPR,
+                              const PPCSubtarget &Subtarget) {
+  
+  assert(0 && "VAARG in ELF32 ABI not implemented yet!");
+}
+
+static SDOperand LowerVASTART(SDOperand Op, SelectionDAG &DAG,
+                              int VarArgsFrameIndex,
+                              int VarArgsStackOffset,
+                              unsigned VarArgsNumGPR,
+                              unsigned VarArgsNumFPR,
+                              const PPCSubtarget &Subtarget) {
+
+  if (Subtarget.isMachoABI()) {
+    // vastart just stores the address of the VarArgsFrameIndex slot into the
+    // memory location argument.
+    MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+    SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, PtrVT);
+    SrcValueSDNode *SV = cast<SrcValueSDNode>(Op.getOperand(2));
+    return DAG.getStore(Op.getOperand(0), FR, Op.getOperand(1), SV->getValue(),
+                        SV->getOffset());
+  }
+
+  // For ELF 32 ABI we follow the layout of the va_list struct.
+  // We suppose the given va_list is already allocated.
+  //
+  // typedef struct {
+  //  char gpr;     /* index into the array of 8 GPRs
+  //                 * stored in the register save area
+  //                 * gpr=0 corresponds to r3,
+  //                 * gpr=1 to r4, etc.
+  //                 */
+  //  char fpr;     /* index into the array of 8 FPRs
+  //                 * stored in the register save area
+  //                 * fpr=0 corresponds to f1,
+  //                 * fpr=1 to f2, etc.
+  //                 */
+  //  char *overflow_arg_area;
+  //                /* location on stack that holds
+  //                 * the next overflow argument
+  //                 */
+  //  char *reg_save_area;
+  //               /* where r3:r10 and f1:f8 (if saved)
+  //                * are stored
+  //                */
+  // } va_list[1];
+
+
+  SDOperand ArgGPR = DAG.getConstant(VarArgsNumGPR, MVT::i8);
+  SDOperand ArgFPR = DAG.getConstant(VarArgsNumFPR, MVT::i8);
+  
+
+  MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+  
+  SDOperand StackOffset = DAG.getFrameIndex(VarArgsStackOffset, PtrVT);
+  SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, PtrVT);
+  
+  SDOperand ConstFrameOffset = DAG.getConstant(MVT::getSizeInBits(PtrVT)/8,
+                                               PtrVT);
+  SDOperand ConstStackOffset = DAG.getConstant(MVT::getSizeInBits(PtrVT)/8 - 1,
+                                               PtrVT);
+  SDOperand ConstFPROffset   = DAG.getConstant(1, PtrVT);
+  
+  SrcValueSDNode *SV = cast<SrcValueSDNode>(Op.getOperand(2));
+  
+  // Store first byte : number of int regs
+  SDOperand firstStore = DAG.getStore(Op.getOperand(0), ArgGPR,
+                                      Op.getOperand(1), SV->getValue(),
+                                      SV->getOffset());
+  SDOperand nextPtr = DAG.getNode(ISD::ADD, PtrVT, Op.getOperand(1),
+                                  ConstFPROffset);
+  
+  // Store second byte : number of float regs
+  SDOperand secondStore = DAG.getStore(firstStore, ArgFPR, nextPtr,
+                                       SV->getValue(), SV->getOffset());
+  nextPtr = DAG.getNode(ISD::ADD, PtrVT, nextPtr, ConstStackOffset);
+  
+  // Store second word : arguments given on stack
+  SDOperand thirdStore = DAG.getStore(secondStore, StackOffset, nextPtr,
+                                      SV->getValue(), SV->getOffset());
+  nextPtr = DAG.getNode(ISD::ADD, PtrVT, nextPtr, ConstFrameOffset);
+
+  // Store third word : arguments given in registers
+  return DAG.getStore(thirdStore, FR, nextPtr, SV->getValue(),
+                      SV->getOffset());
+
+}
+
+#include "PPCGenCallingConv.inc"
+
+/// GetFPR - Get the set of FP registers that should be allocated for arguments,
+/// depending on which subtarget is selected.
+static const unsigned *GetFPR(const PPCSubtarget &Subtarget) {
+  if (Subtarget.isMachoABI()) {
+    static const unsigned FPR[] = {
+      PPC::F1, PPC::F2, PPC::F3, PPC::F4, PPC::F5, PPC::F6, PPC::F7,
+      PPC::F8, PPC::F9, PPC::F10, PPC::F11, PPC::F12, PPC::F13
+    };
+    return FPR;
+  }
+  
+  
+  static const unsigned FPR[] = {
+    PPC::F1, PPC::F2, PPC::F3, PPC::F4, PPC::F5, PPC::F6, PPC::F7,
+    PPC::F8
+  };
+  return FPR;
+}
+
+static SDOperand LowerFORMAL_ARGUMENTS(SDOperand Op, SelectionDAG &DAG,
+                                       int &VarArgsFrameIndex,
+                                       int &VarArgsStackOffset,
+                                       unsigned &VarArgsNumGPR,
+                                       unsigned &VarArgsNumFPR,
+                                       const PPCSubtarget &Subtarget) {
+  // TODO: add description of PPC stack frame format, or at least some docs.
+  //
+  MachineFunction &MF = DAG.getMachineFunction();
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  SSARegMap *RegMap = MF.getSSARegMap();
+  SmallVector<SDOperand, 8> ArgValues;
+  SDOperand Root = Op.getOperand(0);
+  
+  MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+  bool isPPC64 = PtrVT == MVT::i64;
+  bool isMachoABI = Subtarget.isMachoABI();
+  bool isELF32_ABI = Subtarget.isELF32_ABI();
+  unsigned PtrByteSize = isPPC64 ? 8 : 4;
+
+  unsigned ArgOffset = PPCFrameInfo::getLinkageSize(isPPC64, isMachoABI);
+  
+  static const unsigned GPR_32[] = {           // 32-bit registers.
+    PPC::R3, PPC::R4, PPC::R5, PPC::R6,
+    PPC::R7, PPC::R8, PPC::R9, PPC::R10,
+  };
+  static const unsigned GPR_64[] = {           // 64-bit registers.
+    PPC::X3, PPC::X4, PPC::X5, PPC::X6,
+    PPC::X7, PPC::X8, PPC::X9, PPC::X10,
+  };
+  
+  static const unsigned *FPR = GetFPR(Subtarget);
+  
+  static const unsigned VR[] = {
+    PPC::V2, PPC::V3, PPC::V4, PPC::V5, PPC::V6, PPC::V7, PPC::V8,
+    PPC::V9, PPC::V10, PPC::V11, PPC::V12, PPC::V13
+  };
+
+  const unsigned Num_GPR_Regs = sizeof(GPR_32)/sizeof(GPR_32[0]);
+  const unsigned Num_FPR_Regs = isMachoABI ? 13 : 8;
+  const unsigned Num_VR_Regs  = sizeof( VR)/sizeof( VR[0]);
+
+  unsigned GPR_idx = 0, FPR_idx = 0, VR_idx = 0;
+  
+  const unsigned *GPR = isPPC64 ? GPR_64 : GPR_32;
+  
+  // Add DAG nodes to load the arguments or copy them out of registers.  On
+  // entry to a function on PPC, the arguments start after the linkage area,
+  // although the first ones are often in registers.
+  // 
+  // In the ELF 32 ABI, GPRs and stack are double word align: an argument
+  // represented with two words (long long or double) must be copied to an
+  // even GPR_idx value or to an even ArgOffset value.
+
+  for (unsigned ArgNo = 0, e = Op.Val->getNumValues()-1; ArgNo != e; ++ArgNo) {
+    SDOperand ArgVal;
+    bool needsLoad = false;
+    MVT::ValueType ObjectVT = Op.getValue(ArgNo).getValueType();
+    unsigned ObjSize = MVT::getSizeInBits(ObjectVT)/8;
+    unsigned ArgSize = ObjSize;
+    unsigned Flags = cast<ConstantSDNode>(Op.getOperand(ArgNo+3))->getValue();
+    unsigned AlignFlag = 1 << ISD::ParamFlags::OrigAlignmentOffs;
+    // See if next argument requires stack alignment in ELF
+    bool Expand = (ObjectVT == MVT::f64) || ((ArgNo + 1 < e) &&
+      (cast<ConstantSDNode>(Op.getOperand(ArgNo+4))->getValue() & AlignFlag) &&
+      (!(Flags & AlignFlag)));
+
+    unsigned CurArgOffset = ArgOffset;
+    switch (ObjectVT) {
+    default: assert(0 && "Unhandled argument type!");
+    case MVT::i32:
+      // Double word align in ELF
+      if (Expand && isELF32_ABI) GPR_idx += (GPR_idx % 2);
+      if (GPR_idx != Num_GPR_Regs) {
+        unsigned VReg = RegMap->createVirtualRegister(&PPC::GPRCRegClass);
+        MF.addLiveIn(GPR[GPR_idx], VReg);
+        ArgVal = DAG.getCopyFromReg(Root, VReg, MVT::i32);
+        ++GPR_idx;
+      } else {
+        needsLoad = true;
+        ArgSize = PtrByteSize;
+      }
+      // Stack align in ELF
+      if (needsLoad && Expand && isELF32_ABI) 
+        ArgOffset += ((ArgOffset/4) % 2) * PtrByteSize;
+      // All int arguments reserve stack space in Macho ABI.
+      if (isMachoABI || needsLoad) ArgOffset += PtrByteSize;
+      break;
+      
+    case MVT::i64:  // PPC64
+      if (GPR_idx != Num_GPR_Regs) {
+        unsigned VReg = RegMap->createVirtualRegister(&PPC::G8RCRegClass);
+        MF.addLiveIn(GPR[GPR_idx], VReg);
+        ArgVal = DAG.getCopyFromReg(Root, VReg, MVT::i64);
+        ++GPR_idx;
+      } else {
+        needsLoad = true;
+      }
+      // All int arguments reserve stack space in Macho ABI.
+      if (isMachoABI || needsLoad) ArgOffset += 8;
+      break;
+      
+    case MVT::f32:
+    case MVT::f64:
+      // Every 4 bytes of argument space consumes one of the GPRs available for
+      // argument passing.
+      if (GPR_idx != Num_GPR_Regs && isMachoABI) {
+        ++GPR_idx;
+        if (ObjSize == 8 && GPR_idx != Num_GPR_Regs && !isPPC64)
+          ++GPR_idx;
+      }
+      if (FPR_idx != Num_FPR_Regs) {
+        unsigned VReg;
+        if (ObjectVT == MVT::f32)
+          VReg = RegMap->createVirtualRegister(&PPC::F4RCRegClass);
+        else
+          VReg = RegMap->createVirtualRegister(&PPC::F8RCRegClass);
+        MF.addLiveIn(FPR[FPR_idx], VReg);
+        ArgVal = DAG.getCopyFromReg(Root, VReg, ObjectVT);
+        ++FPR_idx;
+      } else {
+        needsLoad = true;
+      }
+      
+      // Stack align in ELF
+      if (needsLoad && Expand && isELF32_ABI)
+        ArgOffset += ((ArgOffset/4) % 2) * PtrByteSize;
+      // All FP arguments reserve stack space in Macho ABI.
+      if (isMachoABI || needsLoad) ArgOffset += isPPC64 ? 8 : ObjSize;
+      break;
+    case MVT::v4f32:
+    case MVT::v4i32:
+    case MVT::v8i16:
+    case MVT::v16i8:
+      // Note that vector arguments in registers don't reserve stack space.
+      if (VR_idx != Num_VR_Regs) {
+        unsigned VReg = RegMap->createVirtualRegister(&PPC::VRRCRegClass);
+        MF.addLiveIn(VR[VR_idx], VReg);
+        ArgVal = DAG.getCopyFromReg(Root, VReg, ObjectVT);
+        ++VR_idx;
+      } else {
+        // This should be simple, but requires getting 16-byte aligned stack
+        // values.
+        assert(0 && "Loading VR argument not implemented yet!");
+        needsLoad = true;
+      }
+      break;
+    }
+    
+    // We need to load the argument to a virtual register if we determined above
+    // that we ran out of physical registers of the appropriate type
+    if (needsLoad) {
+      // If the argument is actually used, emit a load from the right stack
+      // slot.
+      if (!Op.Val->hasNUsesOfValue(0, ArgNo)) {
+        int FI = MFI->CreateFixedObject(ObjSize,
+                                        CurArgOffset + (ArgSize - ObjSize));
+        SDOperand FIN = DAG.getFrameIndex(FI, PtrVT);
+        ArgVal = DAG.getLoad(ObjectVT, Root, FIN, NULL, 0);
+      } else {
+        // Don't emit a dead load.
+        ArgVal = DAG.getNode(ISD::UNDEF, ObjectVT);
+      }
+    }
+    
+    ArgValues.push_back(ArgVal);
+  }
+  
+  // If the function takes variable number of arguments, make a frame index for
+  // the start of the first vararg value... for expansion of llvm.va_start.
+  bool isVarArg = cast<ConstantSDNode>(Op.getOperand(2))->getValue() != 0;
+  if (isVarArg) {
+    
+    int depth;
+    if (isELF32_ABI) {
+      VarArgsNumGPR = GPR_idx;
+      VarArgsNumFPR = FPR_idx;
+   
+      // Make room for Num_GPR_Regs, Num_FPR_Regs and for a possible frame
+      // pointer.
+      depth = -(Num_GPR_Regs * MVT::getSizeInBits(PtrVT)/8 +
+                Num_FPR_Regs * MVT::getSizeInBits(MVT::f64)/8 +
+                MVT::getSizeInBits(PtrVT)/8);
+      
+      VarArgsStackOffset = MFI->CreateFixedObject(MVT::getSizeInBits(PtrVT)/8,
+                                                  ArgOffset);
+
+    }
+    else
+      depth = ArgOffset;
+    
+    VarArgsFrameIndex = MFI->CreateFixedObject(MVT::getSizeInBits(PtrVT)/8,
+                                               depth);
+    SDOperand FIN = DAG.getFrameIndex(VarArgsFrameIndex, PtrVT);
+    
+    SmallVector<SDOperand, 8> MemOps;
+    
+    // In ELF 32 ABI, the fixed integer arguments of a variadic function are
+    // stored to the VarArgsFrameIndex on the stack.
+    if (isELF32_ABI) {
+      for (GPR_idx = 0; GPR_idx != VarArgsNumGPR; ++GPR_idx) {
+        SDOperand Val = DAG.getRegister(GPR[GPR_idx], PtrVT);
+        SDOperand Store = DAG.getStore(Root, Val, FIN, NULL, 0);
+        MemOps.push_back(Store);
+        // Increment the address by four for the next argument to store
+        SDOperand PtrOff = DAG.getConstant(MVT::getSizeInBits(PtrVT)/8, PtrVT);
+        FIN = DAG.getNode(ISD::ADD, PtrOff.getValueType(), FIN, PtrOff);
+      }
+    }
+
+    // If this function is vararg, store any remaining integer argument regs
+    // to their spots on the stack so that they may be loaded by deferencing the
+    // result of va_next.
+    for (; GPR_idx != Num_GPR_Regs; ++GPR_idx) {
+      unsigned VReg;
+      if (isPPC64)
+        VReg = RegMap->createVirtualRegister(&PPC::G8RCRegClass);
+      else
+        VReg = RegMap->createVirtualRegister(&PPC::GPRCRegClass);
+
+      MF.addLiveIn(GPR[GPR_idx], VReg);
+      SDOperand Val = DAG.getCopyFromReg(Root, VReg, PtrVT);
+      SDOperand Store = DAG.getStore(Val.getValue(1), Val, FIN, NULL, 0);
+      MemOps.push_back(Store);
+      // Increment the address by four for the next argument to store
+      SDOperand PtrOff = DAG.getConstant(MVT::getSizeInBits(PtrVT)/8, PtrVT);
+      FIN = DAG.getNode(ISD::ADD, PtrOff.getValueType(), FIN, PtrOff);
+    }
+
+    // In ELF 32 ABI, the double arguments are stored to the VarArgsFrameIndex
+    // on the stack.
+    if (isELF32_ABI) {
+      for (FPR_idx = 0; FPR_idx != VarArgsNumFPR; ++FPR_idx) {
+        SDOperand Val = DAG.getRegister(FPR[FPR_idx], MVT::f64);
+        SDOperand Store = DAG.getStore(Root, Val, FIN, NULL, 0);
+        MemOps.push_back(Store);
+        // Increment the address by eight for the next argument to store
+        SDOperand PtrOff = DAG.getConstant(MVT::getSizeInBits(MVT::f64)/8,
+                                           PtrVT);
+        FIN = DAG.getNode(ISD::ADD, PtrOff.getValueType(), FIN, PtrOff);
+      }
+
+      for (; FPR_idx != Num_FPR_Regs; ++FPR_idx) {
+        unsigned VReg;
+        VReg = RegMap->createVirtualRegister(&PPC::F8RCRegClass);
+
+        MF.addLiveIn(FPR[FPR_idx], VReg);
+        SDOperand Val = DAG.getCopyFromReg(Root, VReg, MVT::f64);
+        SDOperand Store = DAG.getStore(Val.getValue(1), Val, FIN, NULL, 0);
+        MemOps.push_back(Store);
+        // Increment the address by eight for the next argument to store
+        SDOperand PtrOff = DAG.getConstant(MVT::getSizeInBits(MVT::f64)/8,
+                                           PtrVT);
+        FIN = DAG.getNode(ISD::ADD, PtrOff.getValueType(), FIN, PtrOff);
+      }
+    }
+
+    if (!MemOps.empty())
+      Root = DAG.getNode(ISD::TokenFactor, MVT::Other,&MemOps[0],MemOps.size());
+  }
+  
+  ArgValues.push_back(Root);
+ 
+  // Return the new list of results.
+  std::vector<MVT::ValueType> RetVT(Op.Val->value_begin(),
+                                    Op.Val->value_end());
+  return DAG.getNode(ISD::MERGE_VALUES, RetVT, &ArgValues[0], ArgValues.size());
+}
+
+/// isCallCompatibleAddress - Return the immediate to use if the specified
+/// 32-bit value is representable in the immediate field of a BxA instruction.
+static SDNode *isBLACompatibleAddress(SDOperand Op, SelectionDAG &DAG) {
+  ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op);
+  if (!C) return 0;
+  
+  int Addr = C->getValue();
+  if ((Addr & 3) != 0 ||  // Low 2 bits are implicitly zero.
+      (Addr << 6 >> 6) != Addr)
+    return 0;  // Top 6 bits have to be sext of immediate.
+  
+  return DAG.getConstant((int)C->getValue() >> 2, MVT::i32).Val;
+}
+
+
+static SDOperand LowerCALL(SDOperand Op, SelectionDAG &DAG,
+                           const PPCSubtarget &Subtarget) {
+  SDOperand Chain  = Op.getOperand(0);
+  bool isVarArg    = cast<ConstantSDNode>(Op.getOperand(2))->getValue() != 0;
+  SDOperand Callee = Op.getOperand(4);
+  unsigned NumOps  = (Op.getNumOperands() - 5) / 2;
+  
+  bool isMachoABI = Subtarget.isMachoABI();
+  bool isELF32_ABI  = Subtarget.isELF32_ABI();
+
+  MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+  bool isPPC64 = PtrVT == MVT::i64;
+  unsigned PtrByteSize = isPPC64 ? 8 : 4;
+  
+  // args_to_use will accumulate outgoing args for the PPCISD::CALL case in
+  // SelectExpr to use to put the arguments in the appropriate registers.
+  std::vector<SDOperand> args_to_use;
+  
+  // Count how many bytes are to be pushed on the stack, including the linkage
+  // area, and parameter passing area.  We start with 24/48 bytes, which is
+  // prereserved space for [SP][CR][LR][3 x unused].
+  unsigned NumBytes = PPCFrameInfo::getLinkageSize(isPPC64, isMachoABI);
+  
+  // Add up all the space actually used.
+  for (unsigned i = 0; i != NumOps; ++i) {
+    unsigned ArgSize =MVT::getSizeInBits(Op.getOperand(5+2*i).getValueType())/8;
+    ArgSize = std::max(ArgSize, PtrByteSize);
+    NumBytes += ArgSize;
+  }
+
+  // The prolog code of the callee may store up to 8 GPR argument registers to
+  // the stack, allowing va_start to index over them in memory if its varargs.
+  // Because we cannot tell if this is needed on the caller side, we have to
+  // conservatively assume that it is needed.  As such, make sure we have at
+  // least enough stack space for the caller to store the 8 GPRs.
+  NumBytes = std::max(NumBytes,
+                      PPCFrameInfo::getMinCallFrameSize(isPPC64, isMachoABI));
+  
+  // Adjust the stack pointer for the new arguments...
+  // These operations are automatically eliminated by the prolog/epilog pass
+  Chain = DAG.getCALLSEQ_START(Chain,
+                               DAG.getConstant(NumBytes, PtrVT));
+  
+  // Set up a copy of the stack pointer for use loading and storing any
+  // arguments that may not fit in the registers available for argument
+  // passing.
+  SDOperand StackPtr;
+  if (isPPC64)
+    StackPtr = DAG.getRegister(PPC::X1, MVT::i64);
+  else
+    StackPtr = DAG.getRegister(PPC::R1, MVT::i32);
+  
+  // Figure out which arguments are going to go in registers, and which in
+  // memory.  Also, if this is a vararg function, floating point operations
+  // must be stored to our stack, and loaded into integer regs as well, if
+  // any integer regs are available for argument passing.
+  unsigned ArgOffset = PPCFrameInfo::getLinkageSize(isPPC64, isMachoABI);
+  unsigned GPR_idx = 0, FPR_idx = 0, VR_idx = 0;
+  
+  static const unsigned GPR_32[] = {           // 32-bit registers.
+    PPC::R3, PPC::R4, PPC::R5, PPC::R6,
+    PPC::R7, PPC::R8, PPC::R9, PPC::R10,
+  };
+  static const unsigned GPR_64[] = {           // 64-bit registers.
+    PPC::X3, PPC::X4, PPC::X5, PPC::X6,
+    PPC::X7, PPC::X8, PPC::X9, PPC::X10,
+  };
+  static const unsigned *FPR = GetFPR(Subtarget);
+  
+  static const unsigned VR[] = {
+    PPC::V2, PPC::V3, PPC::V4, PPC::V5, PPC::V6, PPC::V7, PPC::V8,
+    PPC::V9, PPC::V10, PPC::V11, PPC::V12, PPC::V13
+  };
+  const unsigned NumGPRs = sizeof(GPR_32)/sizeof(GPR_32[0]);
+  const unsigned NumFPRs = isMachoABI ? 13 : 8;
+  const unsigned NumVRs  = sizeof( VR)/sizeof( VR[0]);
+  
+  const unsigned *GPR = isPPC64 ? GPR_64 : GPR_32;
+
+  std::vector<std::pair<unsigned, SDOperand> > RegsToPass;
+  SmallVector<SDOperand, 8> MemOpChains;
+  for (unsigned i = 0; i != NumOps; ++i) {
+    bool inMem = false;
+    SDOperand Arg = Op.getOperand(5+2*i);
+    unsigned Flags = cast<ConstantSDNode>(Op.getOperand(5+2*i+1))->getValue();
+    unsigned AlignFlag = 1 << ISD::ParamFlags::OrigAlignmentOffs;
+    // See if next argument requires stack alignment in ELF
+    unsigned next = 5+2*(i+1)+1;
+    bool Expand = (Arg.getValueType() == MVT::f64) || ((i + 1 < NumOps) &&
+      (cast<ConstantSDNode>(Op.getOperand(next))->getValue() & AlignFlag) &&
+      (!(Flags & AlignFlag)));
+
+    // PtrOff will be used to store the current argument to the stack if a
+    // register cannot be found for it.
+    SDOperand PtrOff;
+    
+    // Stack align in ELF 32
+    if (isELF32_ABI && Expand)
+      PtrOff = DAG.getConstant(ArgOffset + ((ArgOffset/4) % 2) * PtrByteSize,
+                               StackPtr.getValueType());
+    else
+      PtrOff = DAG.getConstant(ArgOffset, StackPtr.getValueType());
+
+    PtrOff = DAG.getNode(ISD::ADD, PtrVT, StackPtr, PtrOff);
+
+    // On PPC64, promote integers to 64-bit values.
+    if (isPPC64 && Arg.getValueType() == MVT::i32) {
+      unsigned ExtOp = (Flags & 1) ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
+
+      Arg = DAG.getNode(ExtOp, MVT::i64, Arg);
+    }
+    
+    switch (Arg.getValueType()) {
+    default: assert(0 && "Unexpected ValueType for argument!");
+    case MVT::i32:
+    case MVT::i64:
+      // Double word align in ELF
+      if (isELF32_ABI && Expand) GPR_idx += (GPR_idx % 2);
+      if (GPR_idx != NumGPRs) {
+        RegsToPass.push_back(std::make_pair(GPR[GPR_idx++], Arg));
+      } else {
+        MemOpChains.push_back(DAG.getStore(Chain, Arg, PtrOff, NULL, 0));
+        inMem = true;
+      }
+      if (inMem || isMachoABI) {
+        // Stack align in ELF
+        if (isELF32_ABI && Expand)
+          ArgOffset += ((ArgOffset/4) % 2) * PtrByteSize;
+
+        ArgOffset += PtrByteSize;
+      }
+      break;
+    case MVT::f32:
+    case MVT::f64:
+      if (isVarArg) {
+        // Float varargs need to be promoted to double.
+        if (Arg.getValueType() == MVT::f32)
+          Arg = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Arg);
+      }
+    
+      if (FPR_idx != NumFPRs) {
+        RegsToPass.push_back(std::make_pair(FPR[FPR_idx++], Arg));
+
+        if (isVarArg) {
+          SDOperand Store = DAG.getStore(Chain, Arg, PtrOff, NULL, 0);
+          MemOpChains.push_back(Store);
+
+          // Float varargs are always shadowed in available integer registers
+          if (GPR_idx != NumGPRs) {
+            SDOperand Load = DAG.getLoad(PtrVT, Store, PtrOff, NULL, 0);
+            MemOpChains.push_back(Load.getValue(1));
+            if (isMachoABI) RegsToPass.push_back(std::make_pair(GPR[GPR_idx++],
+                                                                Load));
+          }
+          if (GPR_idx != NumGPRs && Arg.getValueType() == MVT::f64 && !isPPC64){
+            SDOperand ConstFour = DAG.getConstant(4, PtrOff.getValueType());
+            PtrOff = DAG.getNode(ISD::ADD, PtrVT, PtrOff, ConstFour);
+            SDOperand Load = DAG.getLoad(PtrVT, Store, PtrOff, NULL, 0);
+            MemOpChains.push_back(Load.getValue(1));
+            if (isMachoABI) RegsToPass.push_back(std::make_pair(GPR[GPR_idx++],
+                                                                Load));
+          }
+        } else {
+          // If we have any FPRs remaining, we may also have GPRs remaining.
+          // Args passed in FPRs consume either 1 (f32) or 2 (f64) available
+          // GPRs.
+          if (isMachoABI) {
+            if (GPR_idx != NumGPRs)
+              ++GPR_idx;
+            if (GPR_idx != NumGPRs && Arg.getValueType() == MVT::f64 &&
+                !isPPC64)  // PPC64 has 64-bit GPR's obviously :)
+              ++GPR_idx;
+          }
+        }
+      } else {
+        MemOpChains.push_back(DAG.getStore(Chain, Arg, PtrOff, NULL, 0));
+        inMem = true;
+      }
+      if (inMem || isMachoABI) {
+        // Stack align in ELF
+        if (isELF32_ABI && Expand)
+          ArgOffset += ((ArgOffset/4) % 2) * PtrByteSize;
+        if (isPPC64)
+          ArgOffset += 8;
+        else
+          ArgOffset += Arg.getValueType() == MVT::f32 ? 4 : 8;
+      }
+      break;
+    case MVT::v4f32:
+    case MVT::v4i32:
+    case MVT::v8i16:
+    case MVT::v16i8:
+      assert(!isVarArg && "Don't support passing vectors to varargs yet!");
+      assert(VR_idx != NumVRs &&
+             "Don't support passing more than 12 vector args yet!");
+      RegsToPass.push_back(std::make_pair(VR[VR_idx++], Arg));
+      break;
+    }
+  }
+  if (!MemOpChains.empty())
+    Chain = DAG.getNode(ISD::TokenFactor, 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 the appropriate regs.
+  SDOperand InFlag;
+  for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
+    Chain = DAG.getCopyToReg(Chain, RegsToPass[i].first, RegsToPass[i].second,
+                             InFlag);
+    InFlag = Chain.getValue(1);
+  }
+ 
+  // With the ELF 32 ABI, set CR6 to true if this is a vararg call.
+  if (isVarArg && isELF32_ABI) {
+    SDOperand SetCR(DAG.getTargetNode(PPC::SETCR, MVT::i32), 0);
+    Chain = DAG.getCopyToReg(Chain, PPC::CR6, SetCR, InFlag);
+    InFlag = Chain.getValue(1);
+  }
+
+  std::vector<MVT::ValueType> NodeTys;
+  NodeTys.push_back(MVT::Other);   // Returns a chain
+  NodeTys.push_back(MVT::Flag);    // Returns a flag for retval copy to use.
+
+  SmallVector<SDOperand, 8> Ops;
+  unsigned CallOpc = isMachoABI? PPCISD::CALL_Macho : PPCISD::CALL_ELF;
+  
+  // If the callee is a GlobalAddress/ExternalSymbol node (quite common, every
+  // direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol
+  // node so that legalize doesn't hack it.
+  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
+    Callee = DAG.getTargetGlobalAddress(G->getGlobal(), Callee.getValueType());
+  else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee))
+    Callee = DAG.getTargetExternalSymbol(S->getSymbol(), Callee.getValueType());
+  else if (SDNode *Dest = isBLACompatibleAddress(Callee, DAG))
+    // If this is an absolute destination address, use the munged value.
+    Callee = SDOperand(Dest, 0);
+  else {
+    // Otherwise, this is an indirect call.  We have to use a MTCTR/BCTRL pair
+    // to do the call, we can't use PPCISD::CALL.
+    SDOperand MTCTROps[] = {Chain, Callee, InFlag};
+    Chain = DAG.getNode(PPCISD::MTCTR, NodeTys, MTCTROps, 2+(InFlag.Val!=0));
+    InFlag = Chain.getValue(1);
+    
+    // Copy the callee address into R12 on darwin.
+    if (isMachoABI) {
+      Chain = DAG.getCopyToReg(Chain, PPC::R12, Callee, InFlag);
+      InFlag = Chain.getValue(1);
+    }
+
+    NodeTys.clear();
+    NodeTys.push_back(MVT::Other);
+    NodeTys.push_back(MVT::Flag);
+    Ops.push_back(Chain);
+    CallOpc = isMachoABI ? PPCISD::BCTRL_Macho : PPCISD::BCTRL_ELF;
+    Callee.Val = 0;
+  }
+
+  // If this is a direct call, pass the chain and the callee.
+  if (Callee.Val) {
+    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.Val)
+    Ops.push_back(InFlag);
+  Chain = DAG.getNode(CallOpc, NodeTys, &Ops[0], Ops.size());
+  InFlag = Chain.getValue(1);
+
+  SDOperand ResultVals[3];
+  unsigned NumResults = 0;
+  NodeTys.clear();
+  
+  // If the call has results, copy the values out of the ret val registers.
+  switch (Op.Val->getValueType(0)) {
+  default: assert(0 && "Unexpected ret value!");
+  case MVT::Other: break;
+  case MVT::i32:
+    if (Op.Val->getValueType(1) == MVT::i32) {
+      Chain = DAG.getCopyFromReg(Chain, PPC::R3, MVT::i32, InFlag).getValue(1);
+      ResultVals[0] = Chain.getValue(0);
+      Chain = DAG.getCopyFromReg(Chain, PPC::R4, MVT::i32,
+                                 Chain.getValue(2)).getValue(1);
+      ResultVals[1] = Chain.getValue(0);
+      NumResults = 2;
+      NodeTys.push_back(MVT::i32);
+    } else {
+      Chain = DAG.getCopyFromReg(Chain, PPC::R3, MVT::i32, InFlag).getValue(1);
+      ResultVals[0] = Chain.getValue(0);
+      NumResults = 1;
+    }
+    NodeTys.push_back(MVT::i32);
+    break;
+  case MVT::i64:
+    Chain = DAG.getCopyFromReg(Chain, PPC::X3, MVT::i64, InFlag).getValue(1);
+    ResultVals[0] = Chain.getValue(0);
+    NumResults = 1;
+    NodeTys.push_back(MVT::i64);
+    break;
+  case MVT::f32:
+  case MVT::f64:
+    Chain = DAG.getCopyFromReg(Chain, PPC::F1, Op.Val->getValueType(0),
+                               InFlag).getValue(1);
+    ResultVals[0] = Chain.getValue(0);
+    NumResults = 1;
+    NodeTys.push_back(Op.Val->getValueType(0));
+    break;
+  case MVT::v4f32:
+  case MVT::v4i32:
+  case MVT::v8i16:
+  case MVT::v16i8:
+    Chain = DAG.getCopyFromReg(Chain, PPC::V2, Op.Val->getValueType(0),
+                                   InFlag).getValue(1);
+    ResultVals[0] = Chain.getValue(0);
+    NumResults = 1;
+    NodeTys.push_back(Op.Val->getValueType(0));
+    break;
+  }
+  
+  Chain = DAG.getNode(ISD::CALLSEQ_END, MVT::Other, Chain,
+                      DAG.getConstant(NumBytes, PtrVT));
+  NodeTys.push_back(MVT::Other);
+  
+  // If the function returns void, just return the chain.
+  if (NumResults == 0)
+    return Chain;
+  
+  // Otherwise, merge everything together with a MERGE_VALUES node.
+  ResultVals[NumResults++] = Chain;
+  SDOperand Res = DAG.getNode(ISD::MERGE_VALUES, NodeTys,
+                              ResultVals, NumResults);
+  return Res.getValue(Op.ResNo);
+}
+
+static SDOperand LowerRET(SDOperand Op, SelectionDAG &DAG, TargetMachine &TM) {
+  SmallVector<CCValAssign, 16> RVLocs;
+  unsigned CC = DAG.getMachineFunction().getFunction()->getCallingConv();
+  bool isVarArg = DAG.getMachineFunction().getFunction()->isVarArg();
+  CCState CCInfo(CC, isVarArg, TM, RVLocs);
+  CCInfo.AnalyzeReturn(Op.Val, RetCC_PPC);
+  
+  // If this is the first return lowered for this function, add the regs to the
+  // liveout set for the function.
+  if (DAG.getMachineFunction().liveout_empty()) {
+    for (unsigned i = 0; i != RVLocs.size(); ++i)
+      DAG.getMachineFunction().addLiveOut(RVLocs[i].getLocReg());
+  }
+
+  SDOperand Chain = Op.getOperand(0);
+  SDOperand 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, VA.getLocReg(), Op.getOperand(i*2+1), Flag);
+    Flag = Chain.getValue(1);
+  }
+
+  if (Flag.Val)
+    return DAG.getNode(PPCISD::RET_FLAG, MVT::Other, Chain, Flag);
+  else
+    return DAG.getNode(PPCISD::RET_FLAG, MVT::Other, Chain);
+}
+
+static SDOperand LowerSTACKRESTORE(SDOperand Op, SelectionDAG &DAG,
+                                   const PPCSubtarget &Subtarget) {
+  // When we pop the dynamic allocation we need to restore the SP link.
+  
+  // Get the corect type for pointers.
+  MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+
+  // Construct the stack pointer operand.
+  bool IsPPC64 = Subtarget.isPPC64();
+  unsigned SP = IsPPC64 ? PPC::X1 : PPC::R1;
+  SDOperand StackPtr = DAG.getRegister(SP, PtrVT);
+
+  // Get the operands for the STACKRESTORE.
+  SDOperand Chain = Op.getOperand(0);
+  SDOperand SaveSP = Op.getOperand(1);
+  
+  // Load the old link SP.
+  SDOperand LoadLinkSP = DAG.getLoad(PtrVT, Chain, StackPtr, NULL, 0);
+  
+  // Restore the stack pointer.
+  Chain = DAG.getCopyToReg(LoadLinkSP.getValue(1), SP, SaveSP);
+  
+  // Store the old link SP.
+  return DAG.getStore(Chain, LoadLinkSP, StackPtr, NULL, 0);
+}
+
+static SDOperand LowerDYNAMIC_STACKALLOC(SDOperand Op, SelectionDAG &DAG,
+                                         const PPCSubtarget &Subtarget) {
+  MachineFunction &MF = DAG.getMachineFunction();
+  bool IsPPC64 = Subtarget.isPPC64();
+  bool isMachoABI = Subtarget.isMachoABI();
+
+  // Get current frame pointer save index.  The users of this index will be
+  // primarily DYNALLOC instructions.
+  PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
+  int FPSI = FI->getFramePointerSaveIndex();
+   
+  // If the frame pointer save index hasn't been defined yet.
+  if (!FPSI) {
+    // Find out what the fix offset of the frame pointer save area.
+    int FPOffset = PPCFrameInfo::getFramePointerSaveOffset(IsPPC64, isMachoABI);
+    
+    // Allocate the frame index for frame pointer save area.
+    FPSI = MF.getFrameInfo()->CreateFixedObject(IsPPC64? 8 : 4, FPOffset); 
+    // Save the result.
+    FI->setFramePointerSaveIndex(FPSI);                      
+  }
+
+  // Get the inputs.
+  SDOperand Chain = Op.getOperand(0);
+  SDOperand Size  = Op.getOperand(1);
+  
+  // Get the corect type for pointers.
+  MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+  // Negate the size.
+  SDOperand NegSize = DAG.getNode(ISD::SUB, PtrVT,
+                                  DAG.getConstant(0, PtrVT), Size);
+  // Construct a node for the frame pointer save index.
+  SDOperand FPSIdx = DAG.getFrameIndex(FPSI, PtrVT);
+  // Build a DYNALLOC node.
+  SDOperand Ops[3] = { Chain, NegSize, FPSIdx };
+  SDVTList VTs = DAG.getVTList(PtrVT, MVT::Other);
+  return DAG.getNode(PPCISD::DYNALLOC, VTs, Ops, 3);
+}
+
+
+/// LowerSELECT_CC - Lower floating point select_cc's into fsel instruction when
+/// possible.
+static SDOperand LowerSELECT_CC(SDOperand Op, SelectionDAG &DAG) {
+  // Not FP? Not a fsel.
+  if (!MVT::isFloatingPoint(Op.getOperand(0).getValueType()) ||
+      !MVT::isFloatingPoint(Op.getOperand(2).getValueType()))
+    return SDOperand();
+  
+  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
+  
+  // Cannot handle SETEQ/SETNE.
+  if (CC == ISD::SETEQ || CC == ISD::SETNE) return SDOperand();
+  
+  MVT::ValueType ResVT = Op.getValueType();
+  MVT::ValueType CmpVT = Op.getOperand(0).getValueType();
+  SDOperand LHS = Op.getOperand(0), RHS = Op.getOperand(1);
+  SDOperand TV  = Op.getOperand(2), FV  = Op.getOperand(3);
+  
+  // If the RHS of the comparison is a 0.0, we don't need to do the
+  // subtraction at all.
+  if (isFloatingPointZero(RHS))
+    switch (CC) {
+    default: break;       // SETUO etc aren't handled by fsel.
+    case ISD::SETULT:
+    case ISD::SETOLT:
+    case ISD::SETLT:
+      std::swap(TV, FV);  // fsel is natively setge, swap operands for setlt
+    case ISD::SETUGE:
+    case ISD::SETOGE:
+    case ISD::SETGE:
+      if (LHS.getValueType() == MVT::f32)   // Comparison is always 64-bits
+        LHS = DAG.getNode(ISD::FP_EXTEND, MVT::f64, LHS);
+      return DAG.getNode(PPCISD::FSEL, ResVT, LHS, TV, FV);
+    case ISD::SETUGT:
+    case ISD::SETOGT:
+    case ISD::SETGT:
+      std::swap(TV, FV);  // fsel is natively setge, swap operands for setlt
+    case ISD::SETULE:
+    case ISD::SETOLE:
+    case ISD::SETLE:
+      if (LHS.getValueType() == MVT::f32)   // Comparison is always 64-bits
+        LHS = DAG.getNode(ISD::FP_EXTEND, MVT::f64, LHS);
+      return DAG.getNode(PPCISD::FSEL, ResVT,
+                         DAG.getNode(ISD::FNEG, MVT::f64, LHS), TV, FV);
+    }
+      
+      SDOperand Cmp;
+  switch (CC) {
+  default: break;       // SETUO etc aren't handled by fsel.
+  case ISD::SETULT:
+  case ISD::SETOLT:
+  case ISD::SETLT:
+    Cmp = DAG.getNode(ISD::FSUB, CmpVT, LHS, RHS);
+    if (Cmp.getValueType() == MVT::f32)   // Comparison is always 64-bits
+      Cmp = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Cmp);
+      return DAG.getNode(PPCISD::FSEL, ResVT, Cmp, FV, TV);
+  case ISD::SETUGE:
+  case ISD::SETOGE:
+  case ISD::SETGE:
+    Cmp = DAG.getNode(ISD::FSUB, CmpVT, LHS, RHS);
+    if (Cmp.getValueType() == MVT::f32)   // Comparison is always 64-bits
+      Cmp = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Cmp);
+      return DAG.getNode(PPCISD::FSEL, ResVT, Cmp, TV, FV);
+  case ISD::SETUGT:
+  case ISD::SETOGT:
+  case ISD::SETGT:
+    Cmp = DAG.getNode(ISD::FSUB, CmpVT, RHS, LHS);
+    if (Cmp.getValueType() == MVT::f32)   // Comparison is always 64-bits
+      Cmp = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Cmp);
+      return DAG.getNode(PPCISD::FSEL, ResVT, Cmp, FV, TV);
+  case ISD::SETULE:
+  case ISD::SETOLE:
+  case ISD::SETLE:
+    Cmp = DAG.getNode(ISD::FSUB, CmpVT, RHS, LHS);
+    if (Cmp.getValueType() == MVT::f32)   // Comparison is always 64-bits
+      Cmp = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Cmp);
+      return DAG.getNode(PPCISD::FSEL, ResVT, Cmp, TV, FV);
+  }
+  return SDOperand();
+}
+
+static SDOperand LowerFP_TO_SINT(SDOperand Op, SelectionDAG &DAG) {
+  assert(MVT::isFloatingPoint(Op.getOperand(0).getValueType()));
+  SDOperand Src = Op.getOperand(0);
+  if (Src.getValueType() == MVT::f32)
+    Src = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Src);
+  
+  SDOperand Tmp;
+  switch (Op.getValueType()) {
+  default: assert(0 && "Unhandled FP_TO_SINT type in custom expander!");
+  case MVT::i32:
+    Tmp = DAG.getNode(PPCISD::FCTIWZ, MVT::f64, Src);
+    break;
+  case MVT::i64:
+    Tmp = DAG.getNode(PPCISD::FCTIDZ, MVT::f64, Src);
+    break;
+  }
+  
+  // Convert the FP value to an int value through memory.
+  SDOperand Bits = DAG.getNode(ISD::BIT_CONVERT, MVT::i64, Tmp);
+  if (Op.getValueType() == MVT::i32)
+    Bits = DAG.getNode(ISD::TRUNCATE, MVT::i32, Bits);
+  return Bits;
+}
+
+static SDOperand LowerSINT_TO_FP(SDOperand Op, SelectionDAG &DAG) {
+  if (Op.getOperand(0).getValueType() == MVT::i64) {
+    SDOperand Bits = DAG.getNode(ISD::BIT_CONVERT, MVT::f64, Op.getOperand(0));
+    SDOperand FP = DAG.getNode(PPCISD::FCFID, MVT::f64, Bits);
+    if (Op.getValueType() == MVT::f32)
+      FP = DAG.getNode(ISD::FP_ROUND, MVT::f32, FP);
+    return FP;
+  }
+  
+  assert(Op.getOperand(0).getValueType() == MVT::i32 &&
+         "Unhandled SINT_TO_FP type in custom expander!");
+  // Since we only generate this in 64-bit mode, we can take advantage of
+  // 64-bit registers.  In particular, sign extend the input value into the
+  // 64-bit register with extsw, store the WHOLE 64-bit value into the stack
+  // then lfd it and fcfid it.
+  MachineFrameInfo *FrameInfo = DAG.getMachineFunction().getFrameInfo();
+  int FrameIdx = FrameInfo->CreateStackObject(8, 8);
+  MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+  SDOperand FIdx = DAG.getFrameIndex(FrameIdx, PtrVT);
+  
+  SDOperand Ext64 = DAG.getNode(PPCISD::EXTSW_32, MVT::i32,
+                                Op.getOperand(0));
+  
+  // STD the extended value into the stack slot.
+  SDOperand Store = DAG.getNode(PPCISD::STD_32, MVT::Other,
+                                DAG.getEntryNode(), Ext64, FIdx,
+                                DAG.getSrcValue(NULL));
+  // Load the value as a double.
+  SDOperand Ld = DAG.getLoad(MVT::f64, Store, FIdx, NULL, 0);
+  
+  // FCFID it and return it.
+  SDOperand FP = DAG.getNode(PPCISD::FCFID, MVT::f64, Ld);
+  if (Op.getValueType() == MVT::f32)
+    FP = DAG.getNode(ISD::FP_ROUND, MVT::f32, FP);
+  return FP;
+}
+
+static SDOperand LowerSHL_PARTS(SDOperand Op, SelectionDAG &DAG) {
+  assert(Op.getNumOperands() == 3 && Op.getValueType() == MVT::i32 &&
+         Op.getOperand(1).getValueType() == MVT::i32 && "Unexpected SHL!");
+  
+  // Expand into a bunch of logical ops.  Note that these ops
+  // depend on the PPC behavior for oversized shift amounts.
+  SDOperand Lo = Op.getOperand(0);
+  SDOperand Hi = Op.getOperand(1);
+  SDOperand Amt = Op.getOperand(2);
+  
+  SDOperand Tmp1 = DAG.getNode(ISD::SUB, MVT::i32,
+                               DAG.getConstant(32, MVT::i32), Amt);
+  SDOperand Tmp2 = DAG.getNode(PPCISD::SHL, MVT::i32, Hi, Amt);
+  SDOperand Tmp3 = DAG.getNode(PPCISD::SRL, MVT::i32, Lo, Tmp1);
+  SDOperand Tmp4 = DAG.getNode(ISD::OR , MVT::i32, Tmp2, Tmp3);
+  SDOperand Tmp5 = DAG.getNode(ISD::ADD, MVT::i32, Amt,
+                               DAG.getConstant(-32U, MVT::i32));
+  SDOperand Tmp6 = DAG.getNode(PPCISD::SHL, MVT::i32, Lo, Tmp5);
+  SDOperand OutHi = DAG.getNode(ISD::OR, MVT::i32, Tmp4, Tmp6);
+  SDOperand OutLo = DAG.getNode(PPCISD::SHL, MVT::i32, Lo, Amt);
+  SDOperand OutOps[] = { OutLo, OutHi };
+  return DAG.getNode(ISD::MERGE_VALUES, DAG.getVTList(MVT::i32, MVT::i32),
+                     OutOps, 2);
+}
+
+static SDOperand LowerSRL_PARTS(SDOperand Op, SelectionDAG &DAG) {
+  assert(Op.getNumOperands() == 3 && Op.getValueType() == MVT::i32 &&
+         Op.getOperand(1).getValueType() == MVT::i32 && "Unexpected SRL!");
+  
+  // Otherwise, expand into a bunch of logical ops.  Note that these ops
+  // depend on the PPC behavior for oversized shift amounts.
+  SDOperand Lo = Op.getOperand(0);
+  SDOperand Hi = Op.getOperand(1);
+  SDOperand Amt = Op.getOperand(2);
+  
+  SDOperand Tmp1 = DAG.getNode(ISD::SUB, MVT::i32,
+                               DAG.getConstant(32, MVT::i32), Amt);
+  SDOperand Tmp2 = DAG.getNode(PPCISD::SRL, MVT::i32, Lo, Amt);
+  SDOperand Tmp3 = DAG.getNode(PPCISD::SHL, MVT::i32, Hi, Tmp1);
+  SDOperand Tmp4 = DAG.getNode(ISD::OR , MVT::i32, Tmp2, Tmp3);
+  SDOperand Tmp5 = DAG.getNode(ISD::ADD, MVT::i32, Amt,
+                               DAG.getConstant(-32U, MVT::i32));
+  SDOperand Tmp6 = DAG.getNode(PPCISD::SRL, MVT::i32, Hi, Tmp5);
+  SDOperand OutLo = DAG.getNode(ISD::OR, MVT::i32, Tmp4, Tmp6);
+  SDOperand OutHi = DAG.getNode(PPCISD::SRL, MVT::i32, Hi, Amt);
+  SDOperand OutOps[] = { OutLo, OutHi };
+  return DAG.getNode(ISD::MERGE_VALUES, DAG.getVTList(MVT::i32, MVT::i32),
+                     OutOps, 2);
+}
+
+static SDOperand LowerSRA_PARTS(SDOperand Op, SelectionDAG &DAG) {
+  assert(Op.getNumOperands() == 3 && Op.getValueType() == MVT::i32 &&
+         Op.getOperand(1).getValueType() == MVT::i32 && "Unexpected SRA!");
+  
+  // Otherwise, expand into a bunch of logical ops, followed by a select_cc.
+  SDOperand Lo = Op.getOperand(0);
+  SDOperand Hi = Op.getOperand(1);
+  SDOperand Amt = Op.getOperand(2);
+  
+  SDOperand Tmp1 = DAG.getNode(ISD::SUB, MVT::i32,
+                               DAG.getConstant(32, MVT::i32), Amt);
+  SDOperand Tmp2 = DAG.getNode(PPCISD::SRL, MVT::i32, Lo, Amt);
+  SDOperand Tmp3 = DAG.getNode(PPCISD::SHL, MVT::i32, Hi, Tmp1);
+  SDOperand Tmp4 = DAG.getNode(ISD::OR , MVT::i32, Tmp2, Tmp3);
+  SDOperand Tmp5 = DAG.getNode(ISD::ADD, MVT::i32, Amt,
+                               DAG.getConstant(-32U, MVT::i32));
+  SDOperand Tmp6 = DAG.getNode(PPCISD::SRA, MVT::i32, Hi, Tmp5);
+  SDOperand OutHi = DAG.getNode(PPCISD::SRA, MVT::i32, Hi, Amt);
+  SDOperand OutLo = DAG.getSelectCC(Tmp5, DAG.getConstant(0, MVT::i32),
+                                    Tmp4, Tmp6, ISD::SETLE);
+  SDOperand OutOps[] = { OutLo, OutHi };
+  return DAG.getNode(ISD::MERGE_VALUES, DAG.getVTList(MVT::i32, MVT::i32),
+                     OutOps, 2);
+}
+
+//===----------------------------------------------------------------------===//
+// Vector related lowering.
+//
+
+// If this is a vector of constants or undefs, get the bits.  A bit in
+// UndefBits is set if the corresponding element of the vector is an 
+// ISD::UNDEF value.  For undefs, the corresponding VectorBits values are
+// zero.   Return true if this is not an array of constants, false if it is.
+//
+static bool GetConstantBuildVectorBits(SDNode *BV, uint64_t VectorBits[2],
+                                       uint64_t UndefBits[2]) {
+  // Start with zero'd results.
+  VectorBits[0] = VectorBits[1] = UndefBits[0] = UndefBits[1] = 0;
+  
+  unsigned EltBitSize = MVT::getSizeInBits(BV->getOperand(0).getValueType());
+  for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) {
+    SDOperand OpVal = BV->getOperand(i);
+    
+    unsigned PartNo = i >= e/2;     // In the upper 128 bits?
+    unsigned SlotNo = e/2 - (i & (e/2-1))-1;  // Which subpiece of the uint64_t.
+
+    uint64_t EltBits = 0;
+    if (OpVal.getOpcode() == ISD::UNDEF) {
+      uint64_t EltUndefBits = ~0U >> (32-EltBitSize);
+      UndefBits[PartNo] |= EltUndefBits << (SlotNo*EltBitSize);
+      continue;
+    } else if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(OpVal)) {
+      EltBits = CN->getValue() & (~0U >> (32-EltBitSize));
+    } else if (ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(OpVal)) {
+      assert(CN->getValueType(0) == MVT::f32 &&
+             "Only one legal FP vector type!");
+      EltBits = FloatToBits(CN->getValue());
+    } else {
+      // Nonconstant element.
+      return true;
+    }
+    
+    VectorBits[PartNo] |= EltBits << (SlotNo*EltBitSize);
+  }
+  
+  //printf("%llx %llx  %llx %llx\n", 
+  //       VectorBits[0], VectorBits[1], UndefBits[0], UndefBits[1]);
+  return false;
+}
+
+// If this is a splat (repetition) of a value across the whole vector, return
+// the smallest size that splats it.  For example, "0x01010101010101..." is a
+// splat of 0x01, 0x0101, and 0x01010101.  We return SplatBits = 0x01 and 
+// SplatSize = 1 byte.
+static bool isConstantSplat(const uint64_t Bits128[2], 
+                            const uint64_t Undef128[2],
+                            unsigned &SplatBits, unsigned &SplatUndef,
+                            unsigned &SplatSize) {
+  
+  // Don't let undefs prevent splats from matching.  See if the top 64-bits are
+  // the same as the lower 64-bits, ignoring undefs.
+  if ((Bits128[0] & ~Undef128[1]) != (Bits128[1] & ~Undef128[0]))
+    return false;  // Can't be a splat if two pieces don't match.
+  
+  uint64_t Bits64  = Bits128[0] | Bits128[1];
+  uint64_t Undef64 = Undef128[0] & Undef128[1];
+  
+  // Check that the top 32-bits are the same as the lower 32-bits, ignoring
+  // undefs.
+  if ((Bits64 & (~Undef64 >> 32)) != ((Bits64 >> 32) & ~Undef64))
+    return false;  // Can't be a splat if two pieces don't match.
+
+  uint32_t Bits32  = uint32_t(Bits64) | uint32_t(Bits64 >> 32);
+  uint32_t Undef32 = uint32_t(Undef64) & uint32_t(Undef64 >> 32);
+
+  // If the top 16-bits are different than the lower 16-bits, ignoring
+  // undefs, we have an i32 splat.
+  if ((Bits32 & (~Undef32 >> 16)) != ((Bits32 >> 16) & ~Undef32)) {
+    SplatBits = Bits32;
+    SplatUndef = Undef32;
+    SplatSize = 4;
+    return true;
+  }
+  
+  uint16_t Bits16  = uint16_t(Bits32)  | uint16_t(Bits32 >> 16);
+  uint16_t Undef16 = uint16_t(Undef32) & uint16_t(Undef32 >> 16);
+
+  // If the top 8-bits are different than the lower 8-bits, ignoring
+  // undefs, we have an i16 splat.
+  if ((Bits16 & (uint16_t(~Undef16) >> 8)) != ((Bits16 >> 8) & ~Undef16)) {
+    SplatBits = Bits16;
+    SplatUndef = Undef16;
+    SplatSize = 2;
+    return true;
+  }
+  
+  // Otherwise, we have an 8-bit splat.
+  SplatBits  = uint8_t(Bits16)  | uint8_t(Bits16 >> 8);
+  SplatUndef = uint8_t(Undef16) & uint8_t(Undef16 >> 8);
+  SplatSize = 1;
+  return true;
+}
+
+/// BuildSplatI - Build a canonical splati of Val with an element size of
+/// SplatSize.  Cast the result to VT.
+static SDOperand BuildSplatI(int Val, unsigned SplatSize, MVT::ValueType VT,
+                             SelectionDAG &DAG) {
+  assert(Val >= -16 && Val <= 15 && "vsplti is out of range!");
+
+  static const MVT::ValueType VTys[] = { // canonical VT to use for each size.
+    MVT::v16i8, MVT::v8i16, MVT::Other, MVT::v4i32
+  };
+
+  MVT::ValueType ReqVT = VT != MVT::Other ? VT : VTys[SplatSize-1];
+  
+  // Force vspltis[hw] -1 to vspltisb -1 to canonicalize.
+  if (Val == -1)
+    SplatSize = 1;
+  
+  MVT::ValueType CanonicalVT = VTys[SplatSize-1];
+  
+  // Build a canonical splat for this value.
+  SDOperand Elt = DAG.getConstant(Val, MVT::getVectorElementType(CanonicalVT));
+  SmallVector<SDOperand, 8> Ops;
+  Ops.assign(MVT::getVectorNumElements(CanonicalVT), Elt);
+  SDOperand Res = DAG.getNode(ISD::BUILD_VECTOR, CanonicalVT,
+                              &Ops[0], Ops.size());
+  return DAG.getNode(ISD::BIT_CONVERT, ReqVT, Res);
+}
+
+/// BuildIntrinsicOp - Return a binary operator intrinsic node with the
+/// specified intrinsic ID.
+static SDOperand BuildIntrinsicOp(unsigned IID, SDOperand LHS, SDOperand RHS,
+                                  SelectionDAG &DAG, 
+                                  MVT::ValueType DestVT = MVT::Other) {
+  if (DestVT == MVT::Other) DestVT = LHS.getValueType();
+  return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DestVT,
+                     DAG.getConstant(IID, MVT::i32), LHS, RHS);
+}
+
+/// BuildIntrinsicOp - Return a ternary operator intrinsic node with the
+/// specified intrinsic ID.
+static SDOperand BuildIntrinsicOp(unsigned IID, SDOperand Op0, SDOperand Op1,
+                                  SDOperand Op2, SelectionDAG &DAG, 
+                                  MVT::ValueType DestVT = MVT::Other) {
+  if (DestVT == MVT::Other) DestVT = Op0.getValueType();
+  return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DestVT,
+                     DAG.getConstant(IID, MVT::i32), Op0, Op1, Op2);
+}
+
+
+/// BuildVSLDOI - Return a VECTOR_SHUFFLE that is a vsldoi of the specified
+/// amount.  The result has the specified value type.
+static SDOperand BuildVSLDOI(SDOperand LHS, SDOperand RHS, unsigned Amt,
+                             MVT::ValueType VT, SelectionDAG &DAG) {
+  // Force LHS/RHS to be the right type.
+  LHS = DAG.getNode(ISD::BIT_CONVERT, MVT::v16i8, LHS);
+  RHS = DAG.getNode(ISD::BIT_CONVERT, MVT::v16i8, RHS);
+  
+  SDOperand Ops[16];
+  for (unsigned i = 0; i != 16; ++i)
+    Ops[i] = DAG.getConstant(i+Amt, MVT::i32);
+  SDOperand T = DAG.getNode(ISD::VECTOR_SHUFFLE, MVT::v16i8, LHS, RHS,
+                            DAG.getNode(ISD::BUILD_VECTOR, MVT::v16i8, Ops,16));
+  return DAG.getNode(ISD::BIT_CONVERT, VT, T);
+}
+
+// If this is a case we can't handle, return null and let the default
+// expansion code take care of it.  If we CAN select this case, and if it
+// selects to a single instruction, return Op.  Otherwise, if we can codegen
+// this case more efficiently than a constant pool load, lower it to the
+// sequence of ops that should be used.
+static SDOperand LowerBUILD_VECTOR(SDOperand Op, SelectionDAG &DAG) {
+  // If this is a vector of constants or undefs, get the bits.  A bit in
+  // UndefBits is set if the corresponding element of the vector is an 
+  // ISD::UNDEF value.  For undefs, the corresponding VectorBits values are
+  // zero. 
+  uint64_t VectorBits[2];
+  uint64_t UndefBits[2];
+  if (GetConstantBuildVectorBits(Op.Val, VectorBits, UndefBits))
+    return SDOperand();   // Not a constant vector.
+  
+  // If this is a splat (repetition) of a value across the whole vector, return
+  // the smallest size that splats it.  For example, "0x01010101010101..." is a
+  // splat of 0x01, 0x0101, and 0x01010101.  We return SplatBits = 0x01 and 
+  // SplatSize = 1 byte.
+  unsigned SplatBits, SplatUndef, SplatSize;
+  if (isConstantSplat(VectorBits, UndefBits, SplatBits, SplatUndef, SplatSize)){
+    bool HasAnyUndefs = (UndefBits[0] | UndefBits[1]) != 0;
+    
+    // First, handle single instruction cases.
+    
+    // All zeros?
+    if (SplatBits == 0) {
+      // Canonicalize all zero vectors to be v4i32.
+      if (Op.getValueType() != MVT::v4i32 || HasAnyUndefs) {
+        SDOperand Z = DAG.getConstant(0, MVT::i32);
+        Z = DAG.getNode(ISD::BUILD_VECTOR, MVT::v4i32, Z, Z, Z, Z);
+        Op = DAG.getNode(ISD::BIT_CONVERT, Op.getValueType(), Z);
+      }
+      return Op;
+    }
+
+    // If the sign extended value is in the range [-16,15], use VSPLTI[bhw].
+    int32_t SextVal= int32_t(SplatBits << (32-8*SplatSize)) >> (32-8*SplatSize);
+    if (SextVal >= -16 && SextVal <= 15)
+      return BuildSplatI(SextVal, SplatSize, Op.getValueType(), DAG);
+    
+    
+    // Two instruction sequences.
+    
+    // If this value is in the range [-32,30] and is even, use:
+    //    tmp = VSPLTI[bhw], result = add tmp, tmp
+    if (SextVal >= -32 && SextVal <= 30 && (SextVal & 1) == 0) {
+      Op = BuildSplatI(SextVal >> 1, SplatSize, Op.getValueType(), DAG);
+      return DAG.getNode(ISD::ADD, Op.getValueType(), Op, Op);
+    }
+    
+    // If this is 0x8000_0000 x 4, turn into vspltisw + vslw.  If it is 
+    // 0x7FFF_FFFF x 4, turn it into not(0x8000_0000).  This is important
+    // for fneg/fabs.
+    if (SplatSize == 4 && SplatBits == (0x7FFFFFFF&~SplatUndef)) {
+      // Make -1 and vspltisw -1:
+      SDOperand OnesV = BuildSplatI(-1, 4, MVT::v4i32, DAG);
+      
+      // Make the VSLW intrinsic, computing 0x8000_0000.
+      SDOperand Res = BuildIntrinsicOp(Intrinsic::ppc_altivec_vslw, OnesV, 
+                                       OnesV, DAG);
+      
+      // xor by OnesV to invert it.
+      Res = DAG.getNode(ISD::XOR, MVT::v4i32, Res, OnesV);
+      return DAG.getNode(ISD::BIT_CONVERT, Op.getValueType(), Res);
+    }
+
+    // Check to see if this is a wide variety of vsplti*, binop self cases.
+    unsigned SplatBitSize = SplatSize*8;
+    static const signed char SplatCsts[] = {
+      -1, 1, -2, 2, -3, 3, -4, 4, -5, 5, -6, 6, -7, 7,
+      -8, 8, -9, 9, -10, 10, -11, 11, -12, 12, -13, 13, 14, -14, 15, -15, -16
+    };
+    
+    for (unsigned idx = 0; idx < sizeof(SplatCsts)/sizeof(SplatCsts[0]); ++idx){
+      // Indirect through the SplatCsts array so that we favor 'vsplti -1' for
+      // cases which are ambiguous (e.g. formation of 0x8000_0000).  'vsplti -1'
+      int i = SplatCsts[idx];
+      
+      // Figure out what shift amount will be used by altivec if shifted by i in
+      // this splat size.
+      unsigned TypeShiftAmt = i & (SplatBitSize-1);
+      
+      // vsplti + shl self.
+      if (SextVal == (i << (int)TypeShiftAmt)) {
+        SDOperand Res = BuildSplatI(i, SplatSize, MVT::Other, DAG);
+        static const unsigned IIDs[] = { // Intrinsic to use for each size.
+          Intrinsic::ppc_altivec_vslb, Intrinsic::ppc_altivec_vslh, 0,
+          Intrinsic::ppc_altivec_vslw
+        };
+        Res = BuildIntrinsicOp(IIDs[SplatSize-1], Res, Res, DAG);
+        return DAG.getNode(ISD::BIT_CONVERT, Op.getValueType(), Res);
+      }
+      
+      // vsplti + srl self.
+      if (SextVal == (int)((unsigned)i >> TypeShiftAmt)) {
+        SDOperand Res = BuildSplatI(i, SplatSize, MVT::Other, DAG);
+        static const unsigned IIDs[] = { // Intrinsic to use for each size.
+          Intrinsic::ppc_altivec_vsrb, Intrinsic::ppc_altivec_vsrh, 0,
+          Intrinsic::ppc_altivec_vsrw
+        };
+        Res = BuildIntrinsicOp(IIDs[SplatSize-1], Res, Res, DAG);
+        return DAG.getNode(ISD::BIT_CONVERT, Op.getValueType(), Res);
+      }
+      
+      // vsplti + sra self.
+      if (SextVal == (int)((unsigned)i >> TypeShiftAmt)) {
+        SDOperand Res = BuildSplatI(i, SplatSize, MVT::Other, DAG);
+        static const unsigned IIDs[] = { // Intrinsic to use for each size.
+          Intrinsic::ppc_altivec_vsrab, Intrinsic::ppc_altivec_vsrah, 0,
+          Intrinsic::ppc_altivec_vsraw
+        };
+        Res = BuildIntrinsicOp(IIDs[SplatSize-1], Res, Res, DAG);
+        return DAG.getNode(ISD::BIT_CONVERT, Op.getValueType(), Res);
+      }
+      
+      // vsplti + rol self.
+      if (SextVal == (int)(((unsigned)i << TypeShiftAmt) |
+                           ((unsigned)i >> (SplatBitSize-TypeShiftAmt)))) {
+        SDOperand Res = BuildSplatI(i, SplatSize, MVT::Other, DAG);
+        static const unsigned IIDs[] = { // Intrinsic to use for each size.
+          Intrinsic::ppc_altivec_vrlb, Intrinsic::ppc_altivec_vrlh, 0,
+          Intrinsic::ppc_altivec_vrlw
+        };
+        Res = BuildIntrinsicOp(IIDs[SplatSize-1], Res, Res, DAG);
+        return DAG.getNode(ISD::BIT_CONVERT, Op.getValueType(), Res);
+      }
+
+      // t = vsplti c, result = vsldoi t, t, 1
+      if (SextVal == ((i << 8) | (i >> (TypeShiftAmt-8)))) {
+        SDOperand T = BuildSplatI(i, SplatSize, MVT::v16i8, DAG);
+        return BuildVSLDOI(T, T, 1, Op.getValueType(), DAG);
+      }
+      // t = vsplti c, result = vsldoi t, t, 2
+      if (SextVal == ((i << 16) | (i >> (TypeShiftAmt-16)))) {
+        SDOperand T = BuildSplatI(i, SplatSize, MVT::v16i8, DAG);
+        return BuildVSLDOI(T, T, 2, Op.getValueType(), DAG);
+      }
+      // t = vsplti c, result = vsldoi t, t, 3
+      if (SextVal == ((i << 24) | (i >> (TypeShiftAmt-24)))) {
+        SDOperand T = BuildSplatI(i, SplatSize, MVT::v16i8, DAG);
+        return BuildVSLDOI(T, T, 3, Op.getValueType(), DAG);
+      }
+    }
+    
+    // Three instruction sequences.
+    
+    // Odd, in range [17,31]:  (vsplti C)-(vsplti -16).
+    if (SextVal >= 0 && SextVal <= 31) {
+      SDOperand LHS = BuildSplatI(SextVal-16, SplatSize, MVT::Other, DAG);
+      SDOperand RHS = BuildSplatI(-16, SplatSize, MVT::Other, DAG);
+      LHS = DAG.getNode(ISD::SUB, Op.getValueType(), LHS, RHS);
+      return DAG.getNode(ISD::BIT_CONVERT, Op.getValueType(), LHS);
+    }
+    // Odd, in range [-31,-17]:  (vsplti C)+(vsplti -16).
+    if (SextVal >= -31 && SextVal <= 0) {
+      SDOperand LHS = BuildSplatI(SextVal+16, SplatSize, MVT::Other, DAG);
+      SDOperand RHS = BuildSplatI(-16, SplatSize, MVT::Other, DAG);
+      LHS = DAG.getNode(ISD::ADD, Op.getValueType(), LHS, RHS);
+      return DAG.getNode(ISD::BIT_CONVERT, Op.getValueType(), LHS);
+    }
+  }
+    
+  return SDOperand();
+}
+
+/// GeneratePerfectShuffle - Given an entry in the perfect-shuffle table, emit
+/// the specified operations to build the shuffle.
+static SDOperand GeneratePerfectShuffle(unsigned PFEntry, SDOperand LHS,
+                                        SDOperand RHS, SelectionDAG &DAG) {
+  unsigned OpNum = (PFEntry >> 26) & 0x0F;
+  unsigned LHSID  = (PFEntry >> 13) & ((1 << 13)-1);
+  unsigned RHSID = (PFEntry >>  0) & ((1 << 13)-1);
+  
+  enum {
+    OP_COPY = 0,  // Copy, used for things like <u,u,u,3> to say it is <0,1,2,3>
+    OP_VMRGHW,
+    OP_VMRGLW,
+    OP_VSPLTISW0,
+    OP_VSPLTISW1,
+    OP_VSPLTISW2,
+    OP_VSPLTISW3,
+    OP_VSLDOI4,
+    OP_VSLDOI8,
+    OP_VSLDOI12
+  };
+  
+  if (OpNum == OP_COPY) {
+    if (LHSID == (1*9+2)*9+3) return LHS;
+    assert(LHSID == ((4*9+5)*9+6)*9+7 && "Illegal OP_COPY!");
+    return RHS;
+  }
+  
+  SDOperand OpLHS, OpRHS;
+  OpLHS = GeneratePerfectShuffle(PerfectShuffleTable[LHSID], LHS, RHS, DAG);
+  OpRHS = GeneratePerfectShuffle(PerfectShuffleTable[RHSID], LHS, RHS, DAG);
+  
+  unsigned ShufIdxs[16];
+  switch (OpNum) {
+  default: assert(0 && "Unknown i32 permute!");
+  case OP_VMRGHW:
+    ShufIdxs[ 0] =  0; ShufIdxs[ 1] =  1; ShufIdxs[ 2] =  2; ShufIdxs[ 3] =  3;
+    ShufIdxs[ 4] = 16; ShufIdxs[ 5] = 17; ShufIdxs[ 6] = 18; ShufIdxs[ 7] = 19;
+    ShufIdxs[ 8] =  4; ShufIdxs[ 9] =  5; ShufIdxs[10] =  6; ShufIdxs[11] =  7;
+    ShufIdxs[12] = 20; ShufIdxs[13] = 21; ShufIdxs[14] = 22; ShufIdxs[15] = 23;
+    break;
+  case OP_VMRGLW:
+    ShufIdxs[ 0] =  8; ShufIdxs[ 1] =  9; ShufIdxs[ 2] = 10; ShufIdxs[ 3] = 11;
+    ShufIdxs[ 4] = 24; ShufIdxs[ 5] = 25; ShufIdxs[ 6] = 26; ShufIdxs[ 7] = 27;
+    ShufIdxs[ 8] = 12; ShufIdxs[ 9] = 13; ShufIdxs[10] = 14; ShufIdxs[11] = 15;
+    ShufIdxs[12] = 28; ShufIdxs[13] = 29; ShufIdxs[14] = 30; ShufIdxs[15] = 31;
+    break;
+  case OP_VSPLTISW0:
+    for (unsigned i = 0; i != 16; ++i)
+      ShufIdxs[i] = (i&3)+0;
+    break;
+  case OP_VSPLTISW1:
+    for (unsigned i = 0; i != 16; ++i)
+      ShufIdxs[i] = (i&3)+4;
+    break;
+  case OP_VSPLTISW2:
+    for (unsigned i = 0; i != 16; ++i)
+      ShufIdxs[i] = (i&3)+8;
+    break;
+  case OP_VSPLTISW3:
+    for (unsigned i = 0; i != 16; ++i)
+      ShufIdxs[i] = (i&3)+12;
+    break;
+  case OP_VSLDOI4:
+    return BuildVSLDOI(OpLHS, OpRHS, 4, OpLHS.getValueType(), DAG);
+  case OP_VSLDOI8:
+    return BuildVSLDOI(OpLHS, OpRHS, 8, OpLHS.getValueType(), DAG);
+  case OP_VSLDOI12:
+    return BuildVSLDOI(OpLHS, OpRHS, 12, OpLHS.getValueType(), DAG);
+  }
+  SDOperand Ops[16];
+  for (unsigned i = 0; i != 16; ++i)
+    Ops[i] = DAG.getConstant(ShufIdxs[i], MVT::i32);
+  
+  return DAG.getNode(ISD::VECTOR_SHUFFLE, OpLHS.getValueType(), OpLHS, OpRHS,
+                     DAG.getNode(ISD::BUILD_VECTOR, MVT::v16i8, Ops, 16));
+}
+
+/// LowerVECTOR_SHUFFLE - Return the code we lower for VECTOR_SHUFFLE.  If this
+/// is a shuffle we can handle in a single instruction, return it.  Otherwise,
+/// return the code it can be lowered into.  Worst case, it can always be
+/// lowered into a vperm.
+static SDOperand LowerVECTOR_SHUFFLE(SDOperand Op, SelectionDAG &DAG) {
+  SDOperand V1 = Op.getOperand(0);
+  SDOperand V2 = Op.getOperand(1);
+  SDOperand PermMask = Op.getOperand(2);
+  
+  // Cases that are handled by instructions that take permute immediates
+  // (such as vsplt*) should be left as VECTOR_SHUFFLE nodes so they can be
+  // selected by the instruction selector.
+  if (V2.getOpcode() == ISD::UNDEF) {
+    if (PPC::isSplatShuffleMask(PermMask.Val, 1) ||
+        PPC::isSplatShuffleMask(PermMask.Val, 2) ||
+        PPC::isSplatShuffleMask(PermMask.Val, 4) ||
+        PPC::isVPKUWUMShuffleMask(PermMask.Val, true) ||
+        PPC::isVPKUHUMShuffleMask(PermMask.Val, true) ||
+        PPC::isVSLDOIShuffleMask(PermMask.Val, true) != -1 ||
+        PPC::isVMRGLShuffleMask(PermMask.Val, 1, true) ||
+        PPC::isVMRGLShuffleMask(PermMask.Val, 2, true) ||
+        PPC::isVMRGLShuffleMask(PermMask.Val, 4, true) ||
+        PPC::isVMRGHShuffleMask(PermMask.Val, 1, true) ||
+        PPC::isVMRGHShuffleMask(PermMask.Val, 2, true) ||
+        PPC::isVMRGHShuffleMask(PermMask.Val, 4, true)) {
+      return Op;
+    }
+  }
+  
+  // Altivec has a variety of "shuffle immediates" that take two vector inputs
+  // and produce a fixed permutation.  If any of these match, do not lower to
+  // VPERM.
+  if (PPC::isVPKUWUMShuffleMask(PermMask.Val, false) ||
+      PPC::isVPKUHUMShuffleMask(PermMask.Val, false) ||
+      PPC::isVSLDOIShuffleMask(PermMask.Val, false) != -1 ||
+      PPC::isVMRGLShuffleMask(PermMask.Val, 1, false) ||
+      PPC::isVMRGLShuffleMask(PermMask.Val, 2, false) ||
+      PPC::isVMRGLShuffleMask(PermMask.Val, 4, false) ||
+      PPC::isVMRGHShuffleMask(PermMask.Val, 1, false) ||
+      PPC::isVMRGHShuffleMask(PermMask.Val, 2, false) ||
+      PPC::isVMRGHShuffleMask(PermMask.Val, 4, false))
+    return Op;
+  
+  // Check to see if this is a shuffle of 4-byte values.  If so, we can use our
+  // perfect shuffle table to emit an optimal matching sequence.
+  unsigned PFIndexes[4];
+  bool isFourElementShuffle = true;
+  for (unsigned i = 0; i != 4 && isFourElementShuffle; ++i) { // Element number
+    unsigned EltNo = 8;   // Start out undef.
+    for (unsigned j = 0; j != 4; ++j) {  // Intra-element byte.
+      if (PermMask.getOperand(i*4+j).getOpcode() == ISD::UNDEF)
+        continue;   // Undef, ignore it.
+      
+      unsigned ByteSource = 
+        cast<ConstantSDNode>(PermMask.getOperand(i*4+j))->getValue();
+      if ((ByteSource & 3) != j) {
+        isFourElementShuffle = false;
+        break;
+      }
+      
+      if (EltNo == 8) {
+        EltNo = ByteSource/4;
+      } else if (EltNo != ByteSource/4) {
+        isFourElementShuffle = false;
+        break;
+      }
+    }
+    PFIndexes[i] = EltNo;
+  }
+    
+  // If this shuffle can be expressed as a shuffle of 4-byte elements, use the 
+  // perfect shuffle vector to determine if it is cost effective to do this as
+  // discrete instructions, or whether we should use a vperm.
+  if (isFourElementShuffle) {
+    // Compute the index in the perfect shuffle table.
+    unsigned PFTableIndex = 
+      PFIndexes[0]*9*9*9+PFIndexes[1]*9*9+PFIndexes[2]*9+PFIndexes[3];
+    
+    unsigned PFEntry = PerfectShuffleTable[PFTableIndex];
+    unsigned Cost  = (PFEntry >> 30);
+    
+    // Determining when to avoid vperm is tricky.  Many things affect the cost
+    // of vperm, particularly how many times the perm mask needs to be computed.
+    // For example, if the perm mask can be hoisted out of a loop or is already
+    // used (perhaps because there are multiple permutes with the same shuffle
+    // mask?) the vperm has a cost of 1.  OTOH, hoisting the permute mask out of
+    // the loop requires an extra register.
+    //
+    // As a compromise, we only emit discrete instructions if the shuffle can be
+    // generated in 3 or fewer operations.  When we have loop information 
+    // available, if this block is within a loop, we should avoid using vperm
+    // for 3-operation perms and use a constant pool load instead.
+    if (Cost < 3) 
+      return GeneratePerfectShuffle(PFEntry, V1, V2, DAG);
+  }
+  
+  // Lower this to a VPERM(V1, V2, V3) expression, where V3 is a constant
+  // vector that will get spilled to the constant pool.
+  if (V2.getOpcode() == ISD::UNDEF) V2 = V1;
+  
+  // The SHUFFLE_VECTOR mask is almost exactly what we want for vperm, except
+  // that it is in input element units, not in bytes.  Convert now.
+  MVT::ValueType EltVT = MVT::getVectorElementType(V1.getValueType());
+  unsigned BytesPerElement = MVT::getSizeInBits(EltVT)/8;
+  
+  SmallVector<SDOperand, 16> ResultMask;
+  for (unsigned i = 0, e = PermMask.getNumOperands(); i != e; ++i) {
+    unsigned SrcElt;
+    if (PermMask.getOperand(i).getOpcode() == ISD::UNDEF)
+      SrcElt = 0;
+    else 
+      SrcElt = cast<ConstantSDNode>(PermMask.getOperand(i))->getValue();
+    
+    for (unsigned j = 0; j != BytesPerElement; ++j)
+      ResultMask.push_back(DAG.getConstant(SrcElt*BytesPerElement+j,
+                                           MVT::i8));
+  }
+  
+  SDOperand VPermMask = DAG.getNode(ISD::BUILD_VECTOR, MVT::v16i8,
+                                    &ResultMask[0], ResultMask.size());
+  return DAG.getNode(PPCISD::VPERM, V1.getValueType(), V1, V2, VPermMask);
+}
+
+/// getAltivecCompareInfo - Given an intrinsic, return false if it is not an
+/// altivec comparison.  If it is, return true and fill in Opc/isDot with
+/// information about the intrinsic.
+static bool getAltivecCompareInfo(SDOperand Intrin, int &CompareOpc,
+                                  bool &isDot) {
+  unsigned IntrinsicID = cast<ConstantSDNode>(Intrin.getOperand(0))->getValue();
+  CompareOpc = -1;
+  isDot = false;
+  switch (IntrinsicID) {
+  default: return false;
+    // Comparison predicates.
+  case Intrinsic::ppc_altivec_vcmpbfp_p:  CompareOpc = 966; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpeqfp_p: CompareOpc = 198; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpequb_p: CompareOpc =   6; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpequh_p: CompareOpc =  70; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpequw_p: CompareOpc = 134; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpgefp_p: CompareOpc = 454; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpgtfp_p: CompareOpc = 710; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpgtsb_p: CompareOpc = 774; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpgtsh_p: CompareOpc = 838; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpgtsw_p: CompareOpc = 902; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpgtub_p: CompareOpc = 518; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpgtuh_p: CompareOpc = 582; isDot = 1; break;
+  case Intrinsic::ppc_altivec_vcmpgtuw_p: CompareOpc = 646; isDot = 1; break;
+    
+    // Normal Comparisons.
+  case Intrinsic::ppc_altivec_vcmpbfp:    CompareOpc = 966; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpeqfp:   CompareOpc = 198; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpequb:   CompareOpc =   6; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpequh:   CompareOpc =  70; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpequw:   CompareOpc = 134; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpgefp:   CompareOpc = 454; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpgtfp:   CompareOpc = 710; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpgtsb:   CompareOpc = 774; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpgtsh:   CompareOpc = 838; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpgtsw:   CompareOpc = 902; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpgtub:   CompareOpc = 518; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpgtuh:   CompareOpc = 582; isDot = 0; break;
+  case Intrinsic::ppc_altivec_vcmpgtuw:   CompareOpc = 646; isDot = 0; break;
+  }
+  return true;
+}
+
+/// LowerINTRINSIC_WO_CHAIN - If this is an intrinsic that we want to custom
+/// lower, do it, otherwise return null.
+static SDOperand LowerINTRINSIC_WO_CHAIN(SDOperand Op, SelectionDAG &DAG) {
+  // If this is a lowered altivec predicate compare, CompareOpc is set to the
+  // opcode number of the comparison.
+  int CompareOpc;
+  bool isDot;
+  if (!getAltivecCompareInfo(Op, CompareOpc, isDot))
+    return SDOperand();    // Don't custom lower most intrinsics.
+  
+  // If this is a non-dot comparison, make the VCMP node and we are done.
+  if (!isDot) {
+    SDOperand Tmp = DAG.getNode(PPCISD::VCMP, Op.getOperand(2).getValueType(),
+                                Op.getOperand(1), Op.getOperand(2),
+                                DAG.getConstant(CompareOpc, MVT::i32));
+    return DAG.getNode(ISD::BIT_CONVERT, Op.getValueType(), Tmp);
+  }
+  
+  // Create the PPCISD altivec 'dot' comparison node.
+  SDOperand Ops[] = {
+    Op.getOperand(2),  // LHS
+    Op.getOperand(3),  // RHS
+    DAG.getConstant(CompareOpc, MVT::i32)
+  };
+  std::vector<MVT::ValueType> VTs;
+  VTs.push_back(Op.getOperand(2).getValueType());
+  VTs.push_back(MVT::Flag);
+  SDOperand CompNode = DAG.getNode(PPCISD::VCMPo, VTs, Ops, 3);
+  
+  // Now that we have the comparison, emit a copy from the CR to a GPR.
+  // This is flagged to the above dot comparison.
+  SDOperand Flags = DAG.getNode(PPCISD::MFCR, MVT::i32,
+                                DAG.getRegister(PPC::CR6, MVT::i32),
+                                CompNode.getValue(1)); 
+  
+  // Unpack the result based on how the target uses it.
+  unsigned BitNo;   // Bit # of CR6.
+  bool InvertBit;   // Invert result?
+  switch (cast<ConstantSDNode>(Op.getOperand(1))->getValue()) {
+  default:  // Can't happen, don't crash on invalid number though.
+  case 0:   // Return the value of the EQ bit of CR6.
+    BitNo = 0; InvertBit = false;
+    break;
+  case 1:   // Return the inverted value of the EQ bit of CR6.
+    BitNo = 0; InvertBit = true;
+    break;
+  case 2:   // Return the value of the LT bit of CR6.
+    BitNo = 2; InvertBit = false;
+    break;
+  case 3:   // Return the inverted value of the LT bit of CR6.
+    BitNo = 2; InvertBit = true;
+    break;
+  }
+  
+  // Shift the bit into the low position.
+  Flags = DAG.getNode(ISD::SRL, MVT::i32, Flags,
+                      DAG.getConstant(8-(3-BitNo), MVT::i32));
+  // Isolate the bit.
+  Flags = DAG.getNode(ISD::AND, MVT::i32, Flags,
+                      DAG.getConstant(1, MVT::i32));
+  
+  // If we are supposed to, toggle the bit.
+  if (InvertBit)
+    Flags = DAG.getNode(ISD::XOR, MVT::i32, Flags,
+                        DAG.getConstant(1, MVT::i32));
+  return Flags;
+}
+
+static SDOperand LowerSCALAR_TO_VECTOR(SDOperand Op, SelectionDAG &DAG) {
+  // Create a stack slot that is 16-byte aligned.
+  MachineFrameInfo *FrameInfo = DAG.getMachineFunction().getFrameInfo();
+  int FrameIdx = FrameInfo->CreateStackObject(16, 16);
+  MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+  SDOperand FIdx = DAG.getFrameIndex(FrameIdx, PtrVT);
+  
+  // Store the input value into Value#0 of the stack slot.
+  SDOperand Store = DAG.getStore(DAG.getEntryNode(),
+                                 Op.getOperand(0), FIdx, NULL, 0);
+  // Load it out.
+  return DAG.getLoad(Op.getValueType(), Store, FIdx, NULL, 0);
+}
+
+static SDOperand LowerMUL(SDOperand Op, SelectionDAG &DAG) {
+  if (Op.getValueType() == MVT::v4i32) {
+    SDOperand LHS = Op.getOperand(0), RHS = Op.getOperand(1);
+    
+    SDOperand Zero  = BuildSplatI(  0, 1, MVT::v4i32, DAG);
+    SDOperand Neg16 = BuildSplatI(-16, 4, MVT::v4i32, DAG); // +16 as shift amt.
+    
+    SDOperand RHSSwap =   // = vrlw RHS, 16
+      BuildIntrinsicOp(Intrinsic::ppc_altivec_vrlw, RHS, Neg16, DAG);
+    
+    // Shrinkify inputs to v8i16.
+    LHS = DAG.getNode(ISD::BIT_CONVERT, MVT::v8i16, LHS);
+    RHS = DAG.getNode(ISD::BIT_CONVERT, MVT::v8i16, RHS);
+    RHSSwap = DAG.getNode(ISD::BIT_CONVERT, MVT::v8i16, RHSSwap);
+    
+    // Low parts multiplied together, generating 32-bit results (we ignore the
+    // top parts).
+    SDOperand LoProd = BuildIntrinsicOp(Intrinsic::ppc_altivec_vmulouh,
+                                        LHS, RHS, DAG, MVT::v4i32);
+    
+    SDOperand HiProd = BuildIntrinsicOp(Intrinsic::ppc_altivec_vmsumuhm,
+                                        LHS, RHSSwap, Zero, DAG, MVT::v4i32);
+    // Shift the high parts up 16 bits.
+    HiProd = BuildIntrinsicOp(Intrinsic::ppc_altivec_vslw, HiProd, Neg16, DAG);
+    return DAG.getNode(ISD::ADD, MVT::v4i32, LoProd, HiProd);
+  } else if (Op.getValueType() == MVT::v8i16) {
+    SDOperand LHS = Op.getOperand(0), RHS = Op.getOperand(1);
+    
+    SDOperand Zero = BuildSplatI(0, 1, MVT::v8i16, DAG);
+
+    return BuildIntrinsicOp(Intrinsic::ppc_altivec_vmladduhm,
+                            LHS, RHS, Zero, DAG);
+  } else if (Op.getValueType() == MVT::v16i8) {
+    SDOperand LHS = Op.getOperand(0), RHS = Op.getOperand(1);
+    
+    // Multiply the even 8-bit parts, producing 16-bit sums.
+    SDOperand EvenParts = BuildIntrinsicOp(Intrinsic::ppc_altivec_vmuleub,
+                                           LHS, RHS, DAG, MVT::v8i16);
+    EvenParts = DAG.getNode(ISD::BIT_CONVERT, MVT::v16i8, EvenParts);
+    
+    // Multiply the odd 8-bit parts, producing 16-bit sums.
+    SDOperand OddParts = BuildIntrinsicOp(Intrinsic::ppc_altivec_vmuloub,
+                                          LHS, RHS, DAG, MVT::v8i16);
+    OddParts = DAG.getNode(ISD::BIT_CONVERT, MVT::v16i8, OddParts);
+    
+    // Merge the results together.
+    SDOperand Ops[16];
+    for (unsigned i = 0; i != 8; ++i) {
+      Ops[i*2  ] = DAG.getConstant(2*i+1, MVT::i8);
+      Ops[i*2+1] = DAG.getConstant(2*i+1+16, MVT::i8);
+    }
+    return DAG.getNode(ISD::VECTOR_SHUFFLE, MVT::v16i8, EvenParts, OddParts,
+                       DAG.getNode(ISD::BUILD_VECTOR, MVT::v16i8, Ops, 16));
+  } else {
+    assert(0 && "Unknown mul to lower!");
+    abort();
+  }
+}
+
+/// LowerOperation - Provide custom lowering hooks for some operations.
+///
+SDOperand PPCTargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
+  switch (Op.getOpcode()) {
+  default: assert(0 && "Wasn't expecting to be able to lower this!"); 
+  case ISD::ConstantPool:       return LowerConstantPool(Op, DAG);
+  case ISD::GlobalAddress:      return LowerGlobalAddress(Op, DAG);
+  case ISD::GlobalTLSAddress:   return LowerGlobalTLSAddress(Op, DAG);
+  case ISD::JumpTable:          return LowerJumpTable(Op, DAG);
+  case ISD::SETCC:              return LowerSETCC(Op, DAG);
+  case ISD::VASTART:            
+    return LowerVASTART(Op, DAG, VarArgsFrameIndex, VarArgsStackOffset,
+                        VarArgsNumGPR, VarArgsNumFPR, PPCSubTarget);
+  
+  case ISD::VAARG:            
+    return LowerVAARG(Op, DAG, VarArgsFrameIndex, VarArgsStackOffset,
+                      VarArgsNumGPR, VarArgsNumFPR, PPCSubTarget);
+
+  case ISD::FORMAL_ARGUMENTS:
+    return LowerFORMAL_ARGUMENTS(Op, DAG, VarArgsFrameIndex, 
+                                 VarArgsStackOffset, VarArgsNumGPR,
+                                 VarArgsNumFPR, PPCSubTarget);
+
+  case ISD::CALL:               return LowerCALL(Op, DAG, PPCSubTarget);
+  case ISD::RET:                return LowerRET(Op, DAG, getTargetMachine());
+  case ISD::STACKRESTORE:       return LowerSTACKRESTORE(Op, DAG, PPCSubTarget);
+  case ISD::DYNAMIC_STACKALLOC:
+    return LowerDYNAMIC_STACKALLOC(Op, DAG, PPCSubTarget);
+    
+  case ISD::SELECT_CC:          return LowerSELECT_CC(Op, DAG);
+  case ISD::FP_TO_SINT:         return LowerFP_TO_SINT(Op, DAG);
+  case ISD::SINT_TO_FP:         return LowerSINT_TO_FP(Op, DAG);
+
+  // Lower 64-bit shifts.
+  case ISD::SHL_PARTS:          return LowerSHL_PARTS(Op, DAG);
+  case ISD::SRL_PARTS:          return LowerSRL_PARTS(Op, DAG);
+  case ISD::SRA_PARTS:          return LowerSRA_PARTS(Op, DAG);
+
+  // Vector-related lowering.
+  case ISD::BUILD_VECTOR:       return LowerBUILD_VECTOR(Op, DAG);
+  case ISD::VECTOR_SHUFFLE:     return LowerVECTOR_SHUFFLE(Op, DAG);
+  case ISD::INTRINSIC_WO_CHAIN: return LowerINTRINSIC_WO_CHAIN(Op, DAG);
+  case ISD::SCALAR_TO_VECTOR:   return LowerSCALAR_TO_VECTOR(Op, DAG);
+  case ISD::MUL:                return LowerMUL(Op, DAG);
+  
+  // Frame & Return address.  Currently unimplemented
+  case ISD::RETURNADDR:         break;
+  case ISD::FRAMEADDR:          return LowerFRAMEADDR(Op, DAG);
+  }
+  return SDOperand();
+}
+
+//===----------------------------------------------------------------------===//
+//  Other Lowering Code
+//===----------------------------------------------------------------------===//
+
+MachineBasicBlock *
+PPCTargetLowering::InsertAtEndOfBasicBlock(MachineInstr *MI,
+                                           MachineBasicBlock *BB) {
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  assert((MI->getOpcode() == PPC::SELECT_CC_I4 ||
+          MI->getOpcode() == PPC::SELECT_CC_I8 ||
+          MI->getOpcode() == PPC::SELECT_CC_F4 ||
+          MI->getOpcode() == PPC::SELECT_CC_F8 ||
+          MI->getOpcode() == PPC::SELECT_CC_VRRC) &&
+         "Unexpected instr type to insert");
+  
+  // To "insert" a SELECT_CC 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();
+  ilist<MachineBasicBlock>::iterator It = BB;
+  ++It;
+  
+  //  thisMBB:
+  //  ...
+  //   TrueVal = ...
+  //   cmpTY ccX, r1, r2
+  //   bCC copy1MBB
+  //   fallthrough --> copy0MBB
+  MachineBasicBlock *thisMBB = BB;
+  MachineBasicBlock *copy0MBB = new MachineBasicBlock(LLVM_BB);
+  MachineBasicBlock *sinkMBB = new MachineBasicBlock(LLVM_BB);
+  unsigned SelectPred = MI->getOperand(4).getImm();
+  BuildMI(BB, TII->get(PPC::BCC))
+    .addImm(SelectPred).addReg(MI->getOperand(1).getReg()).addMBB(sinkMBB);
+  MachineFunction *F = BB->getParent();
+  F->getBasicBlockList().insert(It, copy0MBB);
+  F->getBasicBlockList().insert(It, sinkMBB);
+  // Update machine-CFG edges by first adding all successors of the current
+  // block to the new block which will contain the Phi node for the select.
+  for(MachineBasicBlock::succ_iterator i = BB->succ_begin(), 
+      e = BB->succ_end(); i != e; ++i)
+    sinkMBB->addSuccessor(*i);
+  // Next, remove all successors of the current block, and add the true
+  // and fallthrough blocks as its successors.
+  while(!BB->succ_empty())
+    BB->removeSuccessor(BB->succ_begin());
+  BB->addSuccessor(copy0MBB);
+  BB->addSuccessor(sinkMBB);
+  
+  //  copy0MBB:
+  //   %FalseValue = ...
+  //   # fallthrough to sinkMBB
+  BB = copy0MBB;
+  
+  // Update machine-CFG edges
+  BB->addSuccessor(sinkMBB);
+  
+  //  sinkMBB:
+  //   %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
+  //  ...
+  BB = sinkMBB;
+  BuildMI(BB, TII->get(PPC::PHI), MI->getOperand(0).getReg())
+    .addReg(MI->getOperand(3).getReg()).addMBB(copy0MBB)
+    .addReg(MI->getOperand(2).getReg()).addMBB(thisMBB);
+
+  delete MI;   // The pseudo instruction is gone now.
+  return BB;
+}
+
+//===----------------------------------------------------------------------===//
+// Target Optimization Hooks
+//===----------------------------------------------------------------------===//
+
+SDOperand PPCTargetLowering::PerformDAGCombine(SDNode *N, 
+                                               DAGCombinerInfo &DCI) const {
+  TargetMachine &TM = getTargetMachine();
+  SelectionDAG &DAG = DCI.DAG;
+  switch (N->getOpcode()) {
+  default: break;
+  case PPCISD::SHL:
+    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(N->getOperand(0))) {
+      if (C->getValue() == 0)   // 0 << V -> 0.
+        return N->getOperand(0);
+    }
+    break;
+  case PPCISD::SRL:
+    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(N->getOperand(0))) {
+      if (C->getValue() == 0)   // 0 >>u V -> 0.
+        return N->getOperand(0);
+    }
+    break;
+  case PPCISD::SRA:
+    if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(N->getOperand(0))) {
+      if (C->getValue() == 0 ||   //  0 >>s V -> 0.
+          C->isAllOnesValue())    // -1 >>s V -> -1.
+        return N->getOperand(0);
+    }
+    break;
+    
+  case ISD::SINT_TO_FP:
+    if (TM.getSubtarget<PPCSubtarget>().has64BitSupport()) {
+      if (N->getOperand(0).getOpcode() == ISD::FP_TO_SINT) {
+        // Turn (sint_to_fp (fp_to_sint X)) -> fctidz/fcfid without load/stores.
+        // We allow the src/dst to be either f32/f64, but the intermediate
+        // type must be i64.
+        if (N->getOperand(0).getValueType() == MVT::i64) {
+          SDOperand Val = N->getOperand(0).getOperand(0);
+          if (Val.getValueType() == MVT::f32) {
+            Val = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Val);
+            DCI.AddToWorklist(Val.Val);
+          }
+            
+          Val = DAG.getNode(PPCISD::FCTIDZ, MVT::f64, Val);
+          DCI.AddToWorklist(Val.Val);
+          Val = DAG.getNode(PPCISD::FCFID, MVT::f64, Val);
+          DCI.AddToWorklist(Val.Val);
+          if (N->getValueType(0) == MVT::f32) {
+            Val = DAG.getNode(ISD::FP_ROUND, MVT::f32, Val);
+            DCI.AddToWorklist(Val.Val);
+          }
+          return Val;
+        } else if (N->getOperand(0).getValueType() == MVT::i32) {
+          // If the intermediate type is i32, we can avoid the load/store here
+          // too.
+        }
+      }
+    }
+    break;
+  case ISD::STORE:
+    // Turn STORE (FP_TO_SINT F) -> STFIWX(FCTIWZ(F)).
+    if (TM.getSubtarget<PPCSubtarget>().hasSTFIWX() &&
+        N->getOperand(1).getOpcode() == ISD::FP_TO_SINT &&
+        N->getOperand(1).getValueType() == MVT::i32) {
+      SDOperand Val = N->getOperand(1).getOperand(0);
+      if (Val.getValueType() == MVT::f32) {
+        Val = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Val);
+        DCI.AddToWorklist(Val.Val);
+      }
+      Val = DAG.getNode(PPCISD::FCTIWZ, MVT::f64, Val);
+      DCI.AddToWorklist(Val.Val);
+
+      Val = DAG.getNode(PPCISD::STFIWX, MVT::Other, N->getOperand(0), Val,
+                        N->getOperand(2), N->getOperand(3));
+      DCI.AddToWorklist(Val.Val);
+      return Val;
+    }
+    
+    // Turn STORE (BSWAP) -> sthbrx/stwbrx.
+    if (N->getOperand(1).getOpcode() == ISD::BSWAP &&
+        N->getOperand(1).Val->hasOneUse() &&
+        (N->getOperand(1).getValueType() == MVT::i32 ||
+         N->getOperand(1).getValueType() == MVT::i16)) {
+      SDOperand BSwapOp = N->getOperand(1).getOperand(0);
+      // Do an any-extend to 32-bits if this is a half-word input.
+      if (BSwapOp.getValueType() == MVT::i16)
+        BSwapOp = DAG.getNode(ISD::ANY_EXTEND, MVT::i32, BSwapOp);
+
+      return DAG.getNode(PPCISD::STBRX, MVT::Other, N->getOperand(0), BSwapOp,
+                         N->getOperand(2), N->getOperand(3),
+                         DAG.getValueType(N->getOperand(1).getValueType()));
+    }
+    break;
+  case ISD::BSWAP:
+    // Turn BSWAP (LOAD) -> lhbrx/lwbrx.
+    if (ISD::isNON_EXTLoad(N->getOperand(0).Val) &&
+        N->getOperand(0).hasOneUse() &&
+        (N->getValueType(0) == MVT::i32 || N->getValueType(0) == MVT::i16)) {
+      SDOperand Load = N->getOperand(0);
+      LoadSDNode *LD = cast<LoadSDNode>(Load);
+      // Create the byte-swapping load.
+      std::vector<MVT::ValueType> VTs;
+      VTs.push_back(MVT::i32);
+      VTs.push_back(MVT::Other);
+      SDOperand SV = DAG.getSrcValue(LD->getSrcValue(), LD->getSrcValueOffset());
+      SDOperand Ops[] = {
+        LD->getChain(),    // Chain
+        LD->getBasePtr(),  // Ptr
+        SV,                // SrcValue
+        DAG.getValueType(N->getValueType(0)) // VT
+      };
+      SDOperand BSLoad = DAG.getNode(PPCISD::LBRX, VTs, Ops, 4);
+
+      // If this is an i16 load, insert the truncate.  
+      SDOperand ResVal = BSLoad;
+      if (N->getValueType(0) == MVT::i16)
+        ResVal = DAG.getNode(ISD::TRUNCATE, MVT::i16, BSLoad);
+      
+      // First, combine the bswap away.  This makes the value produced by the
+      // load dead.
+      DCI.CombineTo(N, ResVal);
+
+      // Next, combine the load away, we give it a bogus result value but a real
+      // chain result.  The result value is dead because the bswap is dead.
+      DCI.CombineTo(Load.Val, ResVal, BSLoad.getValue(1));
+      
+      // Return N so it doesn't get rechecked!
+      return SDOperand(N, 0);
+    }
+    
+    break;
+  case PPCISD::VCMP: {
+    // If a VCMPo node already exists with exactly the same operands as this
+    // node, use its result instead of this node (VCMPo computes both a CR6 and
+    // a normal output).
+    //
+    if (!N->getOperand(0).hasOneUse() &&
+        !N->getOperand(1).hasOneUse() &&
+        !N->getOperand(2).hasOneUse()) {
+      
+      // Scan all of the users of the LHS, looking for VCMPo's that match.
+      SDNode *VCMPoNode = 0;
+      
+      SDNode *LHSN = N->getOperand(0).Val;
+      for (SDNode::use_iterator UI = LHSN->use_begin(), E = LHSN->use_end();
+           UI != E; ++UI)
+        if ((*UI)->getOpcode() == PPCISD::VCMPo &&
+            (*UI)->getOperand(1) == N->getOperand(1) &&
+            (*UI)->getOperand(2) == N->getOperand(2) &&
+            (*UI)->getOperand(0) == N->getOperand(0)) {
+          VCMPoNode = *UI;
+          break;
+        }
+      
+      // If there is no VCMPo node, or if the flag value has a single use, don't
+      // transform this.
+      if (!VCMPoNode || VCMPoNode->hasNUsesOfValue(0, 1))
+        break;
+        
+      // Look at the (necessarily single) use of the flag value.  If it has a 
+      // chain, this transformation is more complex.  Note that multiple things
+      // could use the value result, which we should ignore.
+      SDNode *FlagUser = 0;
+      for (SDNode::use_iterator UI = VCMPoNode->use_begin(); 
+           FlagUser == 0; ++UI) {
+        assert(UI != VCMPoNode->use_end() && "Didn't find user!");
+        SDNode *User = *UI;
+        for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) {
+          if (User->getOperand(i) == SDOperand(VCMPoNode, 1)) {
+            FlagUser = User;
+            break;
+          }
+        }
+      }
+      
+      // If the user is a MFCR instruction, we know this is safe.  Otherwise we
+      // give up for right now.
+      if (FlagUser->getOpcode() == PPCISD::MFCR)
+        return SDOperand(VCMPoNode, 0);
+    }
+    break;
+  }
+  case ISD::BR_CC: {
+    // If this is a branch on an altivec predicate comparison, lower this so
+    // that we don't have to do a MFCR: instead, branch directly on CR6.  This
+    // lowering is done pre-legalize, because the legalizer lowers the predicate
+    // compare down to code that is difficult to reassemble.
+    ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(1))->get();
+    SDOperand LHS = N->getOperand(2), RHS = N->getOperand(3);
+    int CompareOpc;
+    bool isDot;
+    
+    if (LHS.getOpcode() == ISD::INTRINSIC_WO_CHAIN &&
+        isa<ConstantSDNode>(RHS) && (CC == ISD::SETEQ || CC == ISD::SETNE) &&
+        getAltivecCompareInfo(LHS, CompareOpc, isDot)) {
+      assert(isDot && "Can't compare against a vector result!");
+      
+      // If this is a comparison against something other than 0/1, then we know
+      // that the condition is never/always true.
+      unsigned Val = cast<ConstantSDNode>(RHS)->getValue();
+      if (Val != 0 && Val != 1) {
+        if (CC == ISD::SETEQ)      // Cond never true, remove branch.
+          return N->getOperand(0);
+        // Always !=, turn it into an unconditional branch.
+        return DAG.getNode(ISD::BR, MVT::Other, 
+                           N->getOperand(0), N->getOperand(4));
+      }
+    
+      bool BranchOnWhenPredTrue = (CC == ISD::SETEQ) ^ (Val == 0);
+      
+      // Create the PPCISD altivec 'dot' comparison node.
+      std::vector<MVT::ValueType> VTs;
+      SDOperand Ops[] = {
+        LHS.getOperand(2),  // LHS of compare
+        LHS.getOperand(3),  // RHS of compare
+        DAG.getConstant(CompareOpc, MVT::i32)
+      };
+      VTs.push_back(LHS.getOperand(2).getValueType());
+      VTs.push_back(MVT::Flag);
+      SDOperand CompNode = DAG.getNode(PPCISD::VCMPo, VTs, Ops, 3);
+      
+      // Unpack the result based on how the target uses it.
+      PPC::Predicate CompOpc;
+      switch (cast<ConstantSDNode>(LHS.getOperand(1))->getValue()) {
+      default:  // Can't happen, don't crash on invalid number though.
+      case 0:   // Branch on the value of the EQ bit of CR6.
+        CompOpc = BranchOnWhenPredTrue ? PPC::PRED_EQ : PPC::PRED_NE;
+        break;
+      case 1:   // Branch on the inverted value of the EQ bit of CR6.
+        CompOpc = BranchOnWhenPredTrue ? PPC::PRED_NE : PPC::PRED_EQ;
+        break;
+      case 2:   // Branch on the value of the LT bit of CR6.
+        CompOpc = BranchOnWhenPredTrue ? PPC::PRED_LT : PPC::PRED_GE;
+        break;
+      case 3:   // Branch on the inverted value of the LT bit of CR6.
+        CompOpc = BranchOnWhenPredTrue ? PPC::PRED_GE : PPC::PRED_LT;
+        break;
+      }
+
+      return DAG.getNode(PPCISD::COND_BRANCH, MVT::Other, N->getOperand(0),
+                         DAG.getConstant(CompOpc, MVT::i32),
+                         DAG.getRegister(PPC::CR6, MVT::i32),
+                         N->getOperand(4), CompNode.getValue(1));
+    }
+    break;
+  }
+  }
+  
+  return SDOperand();
+}
+
+//===----------------------------------------------------------------------===//
+// Inline Assembly Support
+//===----------------------------------------------------------------------===//
+
+void PPCTargetLowering::computeMaskedBitsForTargetNode(const SDOperand Op,
+                                                       uint64_t Mask,
+                                                       uint64_t &KnownZero, 
+                                                       uint64_t &KnownOne,
+                                                       const SelectionDAG &DAG,
+                                                       unsigned Depth) const {
+  KnownZero = 0;
+  KnownOne = 0;
+  switch (Op.getOpcode()) {
+  default: break;
+  case PPCISD::LBRX: {
+    // lhbrx is known to have the top bits cleared out.
+    if (cast<VTSDNode>(Op.getOperand(3))->getVT() == MVT::i16)
+      KnownZero = 0xFFFF0000;
+    break;
+  }
+  case ISD::INTRINSIC_WO_CHAIN: {
+    switch (cast<ConstantSDNode>(Op.getOperand(0))->getValue()) {
+    default: break;
+    case Intrinsic::ppc_altivec_vcmpbfp_p:
+    case Intrinsic::ppc_altivec_vcmpeqfp_p:
+    case Intrinsic::ppc_altivec_vcmpequb_p:
+    case Intrinsic::ppc_altivec_vcmpequh_p:
+    case Intrinsic::ppc_altivec_vcmpequw_p:
+    case Intrinsic::ppc_altivec_vcmpgefp_p:
+    case Intrinsic::ppc_altivec_vcmpgtfp_p:
+    case Intrinsic::ppc_altivec_vcmpgtsb_p:
+    case Intrinsic::ppc_altivec_vcmpgtsh_p:
+    case Intrinsic::ppc_altivec_vcmpgtsw_p:
+    case Intrinsic::ppc_altivec_vcmpgtub_p:
+    case Intrinsic::ppc_altivec_vcmpgtuh_p:
+    case Intrinsic::ppc_altivec_vcmpgtuw_p:
+      KnownZero = ~1U;  // All bits but the low one are known to be zero.
+      break;
+    }        
+  }
+  }
+}
+
+
+/// getConstraintType - Given a constraint, return the type of
+/// constraint it is for this target.
+PPCTargetLowering::ConstraintType 
+PPCTargetLowering::getConstraintType(const std::string &Constraint) const {
+  if (Constraint.size() == 1) {
+    switch (Constraint[0]) {
+    default: break;
+    case 'b':
+    case 'r':
+    case 'f':
+    case 'v':
+    case 'y':
+      return C_RegisterClass;
+    }
+  }
+  return TargetLowering::getConstraintType(Constraint);
+}
+
+std::pair<unsigned, const TargetRegisterClass*> 
+PPCTargetLowering::getRegForInlineAsmConstraint(const std::string &Constraint,
+                                                MVT::ValueType VT) const {
+  if (Constraint.size() == 1) {
+    // GCC RS6000 Constraint Letters
+    switch (Constraint[0]) {
+    case 'b':   // R1-R31
+    case 'r':   // R0-R31
+      if (VT == MVT::i64 && PPCSubTarget.isPPC64())
+        return std::make_pair(0U, PPC::G8RCRegisterClass);
+      return std::make_pair(0U, PPC::GPRCRegisterClass);
+    case 'f':
+      if (VT == MVT::f32)
+        return std::make_pair(0U, PPC::F4RCRegisterClass);
+      else if (VT == MVT::f64)
+        return std::make_pair(0U, PPC::F8RCRegisterClass);
+      break;
+    case 'v': 
+      return std::make_pair(0U, PPC::VRRCRegisterClass);
+    case 'y':   // crrc
+      return std::make_pair(0U, PPC::CRRCRegisterClass);
+    }
+  }
+  
+  return TargetLowering::getRegForInlineAsmConstraint(Constraint, VT);
+}
+
+
+// isOperandValidForConstraint
+SDOperand PPCTargetLowering::
+isOperandValidForConstraint(SDOperand Op, char Letter, SelectionDAG &DAG) {
+  switch (Letter) {
+  default: break;
+  case 'I':
+  case 'J':
+  case 'K':
+  case 'L':
+  case 'M':
+  case 'N':
+  case 'O':
+  case 'P': {
+    ConstantSDNode *CST = dyn_cast<ConstantSDNode>(Op);
+    if (!CST) return SDOperand(0, 0); // Must be an immediate to match.
+    unsigned Value = CST->getValue();
+    switch (Letter) {
+    default: assert(0 && "Unknown constraint letter!");
+    case 'I':  // "I" is a signed 16-bit constant.
+      if ((short)Value == (int)Value)
+        return DAG.getTargetConstant(Value, Op.getValueType());
+      break;
+    case 'J':  // "J" is a constant with only the high-order 16 bits nonzero.
+    case 'L':  // "L" is a signed 16-bit constant shifted left 16 bits.
+      if ((short)Value == 0)
+        return DAG.getTargetConstant(Value, Op.getValueType());
+      break;
+    case 'K':  // "K" is a constant with only the low-order 16 bits nonzero.
+      if ((Value >> 16) == 0)
+        return DAG.getTargetConstant(Value, Op.getValueType());
+      break;
+    case 'M':  // "M" is a constant that is greater than 31.
+      if (Value > 31)
+        return DAG.getTargetConstant(Value, Op.getValueType());
+      break;
+    case 'N':  // "N" is a positive constant that is an exact power of two.
+      if ((int)Value > 0 && isPowerOf2_32(Value))
+        return DAG.getTargetConstant(Value, Op.getValueType());
+      break;
+    case 'O':  // "O" is the constant zero. 
+      if (Value == 0)
+        return DAG.getTargetConstant(Value, Op.getValueType());
+      break;
+    case 'P':  // "P" is a constant whose negation is a signed 16-bit constant.
+      if ((short)-Value == (int)-Value)
+        return DAG.getTargetConstant(Value, Op.getValueType());
+      break;
+    }
+    break;
+  }
+  }
+  
+  // Handle standard constraint letters.
+  return TargetLowering::isOperandValidForConstraint(Op, Letter, DAG);
+}
+
+// isLegalAddressingMode - Return true if the addressing mode represented
+// by AM is legal for this target, for a load/store of the specified type.
+bool PPCTargetLowering::isLegalAddressingMode(const AddrMode &AM, 
+                                              const Type *Ty) const {
+  // FIXME: PPC does not allow r+i addressing modes for vectors!
+  
+  // PPC allows a sign-extended 16-bit immediate field.
+  if (AM.BaseOffs <= -(1LL << 16) || AM.BaseOffs >= (1LL << 16)-1)
+    return false;
+  
+  // No global is ever allowed as a base.
+  if (AM.BaseGV)
+    return false;
+  
+  // PPC only support r+r, 
+  switch (AM.Scale) {
+  case 0:  // "r+i" or just "i", depending on HasBaseReg.
+    break;
+  case 1:
+    if (AM.HasBaseReg && AM.BaseOffs)  // "r+r+i" is not allowed.
+      return false;
+    // Otherwise we have r+r or r+i.
+    break;
+  case 2:
+    if (AM.HasBaseReg || AM.BaseOffs)  // 2*r+r  or  2*r+i is not allowed.
+      return false;
+    // Allow 2*r as r+r.
+    break;
+  default:
+    // No other scales are supported.
+    return false;
+  }
+  
+  return true;
+}
+
+/// isLegalAddressImmediate - Return true if the integer value can be used
+/// as the offset of the target addressing mode for load / store of the
+/// given type.
+bool PPCTargetLowering::isLegalAddressImmediate(int64_t V,const Type *Ty) const{
+  // PPC allows a sign-extended 16-bit immediate field.
+  return (V > -(1 << 16) && V < (1 << 16)-1);
+}
+
+bool PPCTargetLowering::isLegalAddressImmediate(llvm::GlobalValue* GV) const {
+  return false; 
+}
+
+SDOperand PPCTargetLowering::LowerFRAMEADDR(SDOperand Op, SelectionDAG &DAG)
+{
+  // Depths > 0 not supported yet! 
+  if (cast<ConstantSDNode>(Op.getOperand(0))->getValue() > 0)
+    return SDOperand();
+  
+  MVT::ValueType PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
+  bool isPPC64 = PtrVT == MVT::i64;
+  
+  MachineFunction &MF = DAG.getMachineFunction();
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  bool is31 = (NoFramePointerElim || MFI->hasVarSizedObjects()) 
+                  && MFI->getStackSize();
+
+  if (isPPC64)
+    return DAG.getCopyFromReg(DAG.getEntryNode(), is31 ? PPC::X31 : PPC::X1,
+      MVT::i32);
+  else
+    return DAG.getCopyFromReg(DAG.getEntryNode(), is31 ? PPC::R31 : PPC::R1,
+      MVT::i32);
+}