diff --git a/include/llvm/CodeGen/AsmPrinter.h b/include/llvm/CodeGen/AsmPrinter.h
index d1346857006..ddd91620b21 100644
--- a/include/llvm/CodeGen/AsmPrinter.h
+++ b/include/llvm/CodeGen/AsmPrinter.h
@@ -66,6 +66,10 @@ namespace llvm {
     ///
     const TargetAsmInfo *TAI;
 
+    /// Target Register Information.
+    ///
+    const TargetRegisterInfo *TRI;
+
     /// Name-mangler for global names.
     ///
     Mangler *Mang;
@@ -318,6 +322,10 @@ namespace llvm {
     /// printInlineAsm - This method formats and prints the specified machine
     /// instruction that is an inline asm.
     void printInlineAsm(const MachineInstr *MI) const;
+
+    /// printImplicitDef - This method prints the specified machine instruction
+    /// that is an implicit def.
+    virtual void printImplicitDef(const MachineInstr *MI) const;
     
     /// printBasicBlockLabel - This method prints the label for the specified
     /// MachineBasicBlock
diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index d19ca124206..d6acc635a33 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -49,7 +49,8 @@ public:
     LABEL = 2,
     DECLARE = 3,
     EXTRACT_SUBREG = 4,
-    INSERT_SUBREG = 5
+    INSERT_SUBREG = 5,
+    IMPLICIT_DEF = 6
   };
   
   // Target independent implict values for use with subreg insert. All targets
diff --git a/lib/CodeGen/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter.cpp
index 34394608807..c00d4d197c8 100644
--- a/lib/CodeGen/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter.cpp
@@ -29,6 +29,7 @@
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetLowering.h"
 #include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include <cerrno>
 using namespace llvm;
@@ -39,7 +40,8 @@ AsmVerbose("asm-verbose", cl::Hidden, cl::desc("Add comments to directives."));
 char AsmPrinter::ID = 0;
 AsmPrinter::AsmPrinter(std::ostream &o, TargetMachine &tm,
                        const TargetAsmInfo *T)
-  : MachineFunctionPass((intptr_t)&ID), FunctionNumber(0), O(o), TM(tm), TAI(T),
+  : MachineFunctionPass((intptr_t)&ID), FunctionNumber(0), O(o),
+    TM(tm), TAI(T), TRI(tm.getRegisterInfo()),
     IsInTextSection(false)
 {}
 
@@ -1294,6 +1296,13 @@ void AsmPrinter::printInlineAsm(const MachineInstr *MI) const {
   O << "\n\t" << TAI->getInlineAsmEnd() << "\n";
 }
 
+/// printImplicitDef - This method prints the specified machine instruction
+/// that is an implicit def.
+void AsmPrinter::printImplicitDef(const MachineInstr *MI) const {
+  O << "\t" << TAI->getCommentString() << " implicit-def: "
+    << TRI->getAsmName(MI->getOperand(0).getReg()) << "\n";
+}
+
 /// printLabel - This method prints a local label used by debug and
 /// exception handling tables.
 void AsmPrinter::printLabel(const MachineInstr *MI) const {
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
index 45237756a8d..d0d078ab133 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
@@ -467,8 +467,7 @@ void ScheduleDAG::EmitCopyFromReg(SDNode *Node, unsigned ResNo,
   assert(isNew && "Node emitted out of order - early");
 }
 
-void ScheduleDAG::CreateVirtualRegisters(SDNode *Node,
-                                         MachineInstr *MI,
+void ScheduleDAG::CreateVirtualRegisters(SDNode *Node, MachineInstr *MI,
                                          const TargetInstrDesc &II,
                                      DenseMap<SDOperand, unsigned> &VRBaseMap) {
   for (unsigned i = 0; i < II.getNumDefs(); ++i) {
@@ -494,7 +493,13 @@ void ScheduleDAG::CreateVirtualRegisters(SDNode *Node,
     // Create the result registers for this node and add the result regs to
     // the machine instruction.
     if (VRBase == 0) {
-      const TargetRegisterClass *RC = getInstrOperandRegClass(TRI, TII, II, i);
+      const TargetRegisterClass *RC;
+      if (Node->getTargetOpcode() == TargetInstrInfo::IMPLICIT_DEF)
+        // IMPLICIT_DEF can produce any type of result so its TargetInstrDesc
+        // does not include operand register class info.
+        RC = DAG.getTargetLoweringInfo().getRegClassFor(Node->getValueType(0));
+      else
+        RC = getInstrOperandRegClass(TRI, TII, II, i);
       assert(RC && "Isn't a register operand!");
       VRBase = MRI.createVirtualRegister(RC);
       MI->addOperand(MachineOperand::CreateReg(VRBase, true));
diff --git a/lib/Target/ARM/ARMInstrInfo.cpp b/lib/Target/ARM/ARMInstrInfo.cpp
index babee6a43e7..35d63138a22 100644
--- a/lib/Target/ARM/ARMInstrInfo.cpp
+++ b/lib/Target/ARM/ARMInstrInfo.cpp
@@ -877,6 +877,8 @@ unsigned ARM::GetInstSize(MachineInstr *MI) {
       return TAI->getInlineAsmLength(MI->getOperand(0).getSymbolName());
     if (MI->getOpcode() == ARM::LABEL)
       return 0;
+    if (MI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF)
+      return 0;
     assert(0 && "Unknown or unset size field for instr!");
     break;
   case ARMII::Size8Bytes: return 8;          // Arm instruction x 2.
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 49cf624a2d3..34487ff5ef1 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -645,12 +645,6 @@ multiclass AsXI1_bin_c_irs<bits<4> opcod, string opc, PatFrag opnode> {
 //===----------------------------------------------------------------------===//
 //  Miscellaneous Instructions.
 //
-let isImplicitDef = 1 in
-def IMPLICIT_DEF_GPR : 
-PseudoInst<(outs GPR:$rD), (ins pred:$p),
-           "@ IMPLICIT_DEF_GPR $rD",
-           [(set GPR:$rD, (undef))]>;
-
 
 /// CONSTPOOL_ENTRY - This instruction represents a floating constant pool in
 /// the function.  The first operand is the ID# for this instruction, the second
diff --git a/lib/Target/ARM/ARMInstrVFP.td b/lib/Target/ARM/ARMInstrVFP.td
index 011819839ba..9d775ac1666 100644
--- a/lib/Target/ARM/ARMInstrVFP.td
+++ b/lib/Target/ARM/ARMInstrVFP.td
@@ -249,15 +249,6 @@ def FSQRTS  : ASI<(outs SPR:$dst), (ins SPR:$a),
 // FP <-> GPR Copies.  Int <-> FP Conversions.
 //
 
-let isImplicitDef = 1 in {
-def IMPLICIT_DEF_SPR : PseudoInst<(outs SPR:$rD), (ins pred:$p),
-                                  "@ IMPLICIT_DEF_SPR $rD",
-                                  [(set SPR:$rD, (undef))]>;
-def IMPLICIT_DEF_DPR : PseudoInst<(outs DPR:$rD), (ins pred:$p),
-                                  "@ IMPLICIT_DEF_DPR $rD",
-                                  [(set DPR:$rD, (undef))]>;
-}
-
 def FMRS   : ASI<(outs GPR:$dst), (ins SPR:$src),
                  "fmrs", " $dst, $src",
                  [(set GPR:$dst, (bitconvert SPR:$src))]>;
diff --git a/lib/Target/Alpha/AlphaCodeEmitter.cpp b/lib/Target/Alpha/AlphaCodeEmitter.cpp
index 93ef28c5564..0ae99a9dbb9 100644
--- a/lib/Target/Alpha/AlphaCodeEmitter.cpp
+++ b/lib/Target/Alpha/AlphaCodeEmitter.cpp
@@ -95,9 +95,6 @@ void AlphaCodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
     case Alpha::ALTENT:
     case Alpha::PCLABEL:
     case Alpha::MEMLABEL:
-    case Alpha::IDEF_I:
-    case Alpha::IDEF_F32:
-    case Alpha::IDEF_F64:
       break; //skip these
     }
   }
diff --git a/lib/Target/Alpha/AlphaInstrInfo.td b/lib/Target/Alpha/AlphaInstrInfo.td
index 1769ec2a214..ddefe858a26 100644
--- a/lib/Target/Alpha/AlphaInstrInfo.td
+++ b/lib/Target/Alpha/AlphaInstrInfo.td
@@ -141,15 +141,6 @@ class CmpOpFrag<dag res> : PatFrag<(ops node:$R), res>;
 
 //Pseudo ops for selection
 
-let isImplicitDef = 1 in {
-def IDEF_I : PseudoInstAlpha<(outs GPRC:$RA), (ins), ";#idef $RA",
-             [(set GPRC:$RA, (undef))], s_pseudo>;
-def IDEF_F32 : PseudoInstAlpha<(outs F4RC:$RA), (ins), ";#idef $RA",
-             [(set F4RC:$RA, (undef))], s_pseudo>;
-def IDEF_F64 : PseudoInstAlpha<(outs F8RC:$RA), (ins), ";#idef $RA",
-             [(set F8RC:$RA, (undef))], s_pseudo>;
-}
-
 def WTF : PseudoInstAlpha<(outs), (ins variable_ops), "#wtf", [], s_pseudo>;
 
 let hasCtrlDep = 1, Defs = [R30], Uses = [R30] in {
diff --git a/lib/Target/Alpha/AlphaLLRP.cpp b/lib/Target/Alpha/AlphaLLRP.cpp
index 15d12c75931..f4dd199d354 100644
--- a/lib/Target/Alpha/AlphaLLRP.cpp
+++ b/lib/Target/Alpha/AlphaLLRP.cpp
@@ -120,9 +120,6 @@ namespace {
           case Alpha::ALTENT:
           case Alpha::MEMLABEL:
           case Alpha::PCLABEL:
-          case Alpha::IDEF_I:
-          case Alpha::IDEF_F32:
-          case Alpha::IDEF_F64:
             --count;
             break;
           case Alpha::BR:
diff --git a/lib/Target/IA64/IA64InstrInfo.td b/lib/Target/IA64/IA64InstrInfo.td
index 3a266e78f4f..c905d3004e6 100644
--- a/lib/Target/IA64/IA64InstrInfo.td
+++ b/lib/Target/IA64/IA64InstrInfo.td
@@ -456,17 +456,6 @@ def : Pat<(i1  0), (CMPNE r0, r0)>; // TODO: any instruction actually *using*
 // TODO: support postincrement (reg, imm9) loads+stores - this needs more
 // tablegen support
 
-let isImplicitDef = 1 in {
-def IDEF : PseudoInstIA64<(outs variable_ops), (ins), "// IDEF">;
-
-def IDEF_GR_D : PseudoInstIA64_DAG<(outs GR:$reg), (ins), "// $reg = IDEF",
-    [(set GR:$reg, (undef))]>;
-def IDEF_FP_D : PseudoInstIA64_DAG<(outs FP:$reg), (ins), "// $reg = IDEF",
-    [(set FP:$reg, (undef))]>;
-def IDEF_PR_D : PseudoInstIA64_DAG<(outs PR:$reg), (ins), "// $reg = IDEF",
-    [(set PR:$reg, (undef))]>;
-}
-
 def IUSE : PseudoInstIA64<(outs), (ins variable_ops), "// IUSE">;
 def ADJUSTCALLSTACKUP : PseudoInstIA64<(outs), (ins variable_ops),
                                         "// ADJUSTCALLSTACKUP">;
diff --git a/lib/Target/Mips/MipsInstrInfo.td b/lib/Target/Mips/MipsInstrInfo.td
index 9b9e4f73df9..7dcd55ce6c6 100644
--- a/lib/Target/Mips/MipsInstrInfo.td
+++ b/lib/Target/Mips/MipsInstrInfo.td
@@ -355,11 +355,6 @@ def ADJCALLSTACKUP   : PseudoInstMips<(outs), (ins uimm16:$amt1, uimm16:$amt2),
                                       [(callseq_end imm:$amt1, imm:$amt2)]>;
 }
 
-let isImplicitDef = 1 in
-def IMPLICIT_DEF_CPURegs : PseudoInstMips<(outs CPURegs:$dst), (ins),
-                                          "!IMPLICIT_DEF $dst",
-                                          [(set CPURegs:$dst, (undef))]>;
-
 // When handling PIC code the assembler needs .cpload and .cprestore
 // directives. If the real instructions corresponding these directives
 // are used, we have the same behavior, but get also a bunch of warnings
diff --git a/lib/Target/PowerPC/PPCBranchSelector.cpp b/lib/Target/PowerPC/PPCBranchSelector.cpp
index b4b67a2d207..6977093923a 100644
--- a/lib/Target/PowerPC/PPCBranchSelector.cpp
+++ b/lib/Target/PowerPC/PPCBranchSelector.cpp
@@ -59,12 +59,6 @@ FunctionPass *llvm::createPPCBranchSelectionPass() {
 ///
 static unsigned getNumBytesForInstruction(MachineInstr *MI) {
   switch (MI->getOpcode()) {
-  case PPC::IMPLICIT_DEF_GPRC: // no asm emitted
-  case PPC::IMPLICIT_DEF_G8RC: // no asm emitted
-  case PPC::IMPLICIT_DEF_F4:   // no asm emitted
-  case PPC::IMPLICIT_DEF_F8:   // no asm emitted
-  case PPC::IMPLICIT_DEF_VRRC: // no asm emitted
-    return 0;
   case PPC::INLINEASM: {       // Inline Asm: Variable size.
     MachineFunction *MF = MI->getParent()->getParent();
     const char *AsmStr = MI->getOperand(0).getSymbolName();
diff --git a/lib/Target/PowerPC/PPCCodeEmitter.cpp b/lib/Target/PowerPC/PPCCodeEmitter.cpp
index a23f4e41eb6..d2bbebbed97 100644
--- a/lib/Target/PowerPC/PPCCodeEmitter.cpp
+++ b/lib/Target/PowerPC/PPCCodeEmitter.cpp
@@ -112,12 +112,6 @@ void PPCCodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
     case TargetInstrInfo::LABEL:
       MCE.emitLabel(MI.getOperand(0).getImm());
       break;
-    case PPC::IMPLICIT_DEF_GPRC:
-    case PPC::IMPLICIT_DEF_G8RC:
-    case PPC::IMPLICIT_DEF_F8:
-    case PPC::IMPLICIT_DEF_F4:
-    case PPC::IMPLICIT_DEF_VRRC:
-      break; // pseudo opcode, no side effects
     case PPC::MovePCtoLR:
     case PPC::MovePCtoLR8:
       assert(TM.getRelocationModel() == Reloc::PIC_);
diff --git a/lib/Target/PowerPC/PPCInstr64Bit.td b/lib/Target/PowerPC/PPCInstr64Bit.td
index e7b734f76b6..0b7d1cc42a7 100644
--- a/lib/Target/PowerPC/PPCInstr64Bit.td
+++ b/lib/Target/PowerPC/PPCInstr64Bit.td
@@ -53,14 +53,6 @@ def HI48_64 : SDNodeXForm<imm, [{
 }]>;
 
 
-//===----------------------------------------------------------------------===//
-// Pseudo instructions.
-//
-
-def IMPLICIT_DEF_G8RC : Pseudo<(outs G8RC:$rD), (ins),"; IMPLICIT_DEF_G8RC $rD",
-                              [(set G8RC:$rD, (undef))]>;
-
-
 //===----------------------------------------------------------------------===//
 // Calls.
 //
diff --git a/lib/Target/PowerPC/PPCInstrAltivec.td b/lib/Target/PowerPC/PPCInstrAltivec.td
index c006ce0becb..feb538a6fa3 100644
--- a/lib/Target/PowerPC/PPCInstrAltivec.td
+++ b/lib/Target/PowerPC/PPCInstrAltivec.td
@@ -160,9 +160,6 @@ class VX2_Int<bits<11> xo, string opc, Intrinsic IntID>
 //===----------------------------------------------------------------------===//
 // Instruction Definitions.
 
-def IMPLICIT_DEF_VRRC : Pseudo<(outs VRRC:$rD), (ins),"; IMPLICIT_DEF_VRRC $rD",
-                               [(set VRRC:$rD, (v4i32 (undef)))]>;
-
 def DSS      : DSS_Form<822, (outs),
                         (ins u5imm:$ZERO0, u5imm:$STRM,u5imm:$ZERO1,u5imm:$ZERO2),
                         "dss $STRM", LdStGeneral /*FIXME*/, []>;
@@ -579,11 +576,6 @@ def : Pat<(int_ppc_altivec_dstst G8RC:$rA, GPRC:$rB, imm:$STRM),
 def : Pat<(int_ppc_altivec_dststt G8RC:$rA, GPRC:$rB, imm:$STRM),
           (DSTSTT64 1, imm:$STRM, (i64 G8RC:$rA), GPRC:$rB)>;
 
-// Undef.
-def : Pat<(v16i8 (undef)), (IMPLICIT_DEF_VRRC)>;
-def : Pat<(v8i16 (undef)), (IMPLICIT_DEF_VRRC)>;
-def : Pat<(v4f32 (undef)), (IMPLICIT_DEF_VRRC)>;
-
 // Loads.
 def : Pat<(v4i32 (load xoaddr:$src)), (LVX xoaddr:$src)>;
 
diff --git a/lib/Target/PowerPC/PPCInstrInfo.td b/lib/Target/PowerPC/PPCInstrInfo.td
index ed910a9722c..f51158d3b1a 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.td
+++ b/lib/Target/PowerPC/PPCInstrInfo.td
@@ -335,18 +335,6 @@ def DYNALLOC : Pseudo<(outs GPRC:$result), (ins GPRC:$negsize, memri:$fpsi),
                        [(set GPRC:$result,
                              (PPCdynalloc GPRC:$negsize, iaddr:$fpsi))]>;
                          
-let isImplicitDef = 1 in {
-def IMPLICIT_DEF_GPRC: Pseudo<(outs GPRC:$rD), (ins),
-                              "${:comment}IMPLICIT_DEF_GPRC $rD",
-                              [(set GPRC:$rD, (undef))]>;
-def IMPLICIT_DEF_F8  : Pseudo<(outs F8RC:$rD), (ins),
-                              "${:comment} IMPLICIT_DEF_F8 $rD",
-                              [(set F8RC:$rD, (undef))]>;
-def IMPLICIT_DEF_F4  : Pseudo<(outs F4RC:$rD), (ins),
-                              "${:comment} IMPLICIT_DEF_F4 $rD",
-                              [(set F4RC:$rD, (undef))]>;
-}
-
 // SELECT_CC_* - Used to implement the SELECT_CC DAG operation.  Expanded by the
 // scheduler into a branch sequence.
 let usesCustomDAGSchedInserter = 1,    // Expanded by the scheduler.
diff --git a/lib/Target/Sparc/SparcInstrInfo.td b/lib/Target/Sparc/SparcInstrInfo.td
index a70d1419e8d..3ceaf5561bd 100644
--- a/lib/Target/Sparc/SparcInstrInfo.td
+++ b/lib/Target/Sparc/SparcInstrInfo.td
@@ -212,16 +212,6 @@ def ADJCALLSTACKUP : Pseudo<(outs), (ins i32imm:$amt1, i32imm:$amt2),
                             [(callseq_end imm:$amt1, imm:$amt2)]>;
 }
 
-let isImplicitDef = 1 in {
-def IMPLICIT_DEF_Int : Pseudo<(outs IntRegs:$dst), (ins),
-                              "!IMPLICIT_DEF $dst",
-                              [(set IntRegs:$dst, (undef))]>;
-def IMPLICIT_DEF_FP  : Pseudo<(outs FPRegs:$dst), (ins), "!IMPLICIT_DEF $dst",
-                              [(set FPRegs:$dst, (undef))]>;
-def IMPLICIT_DEF_DFP : Pseudo<(outs DFPRegs:$dst), (ins), "!IMPLICIT_DEF $dst",
-                              [(set DFPRegs:$dst, (undef))]>;
-}
-                              
 // FpMOVD/FpNEGD/FpABSD - These are lowered to single-precision ops by the 
 // fpmover pass.
 let Predicates = [HasNoV9] in {  // Only emit these in V8 mode.
diff --git a/lib/Target/Target.td b/lib/Target/Target.td
index ea8f6ec3a15..d7f1e38c118 100644
--- a/lib/Target/Target.td
+++ b/lib/Target/Target.td
@@ -368,6 +368,13 @@ def INSERT_SUBREG : Instruction {
   let Namespace = "TargetInstrInfo";
   let neverHasSideEffects = 1;
 }
+def IMPLICIT_DEF : Instruction {
+  let OutOperandList = (ops unknown:$dst);
+  let InOperandList = (ops);
+  let AsmString = "";
+  let Namespace = "TargetInstrInfo";
+  let neverHasSideEffects = 1;
+}
 
 //===----------------------------------------------------------------------===//
 // AsmWriter - This class can be implemented by targets that need to customize
diff --git a/lib/Target/X86/X86ATTAsmPrinter.cpp b/lib/Target/X86/X86ATTAsmPrinter.cpp
index e51e065540e..ea003c33193 100644
--- a/lib/Target/X86/X86ATTAsmPrinter.cpp
+++ b/lib/Target/X86/X86ATTAsmPrinter.cpp
@@ -205,7 +205,6 @@ static inline bool printStub(TargetMachine &TM, const X86Subtarget* ST) {
 void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
                                     const char *Modifier, bool NotRIPRel) {
   const MachineOperand &MO = MI->getOperand(OpNo);
-  const TargetRegisterInfo &RI = *TM.getRegisterInfo();
   switch (MO.getType()) {
   case MachineOperand::MO_Register: {
     assert(TargetRegisterInfo::isPhysicalRegister(MO.getReg()) &&
@@ -218,7 +217,7 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
                     ((strcmp(Modifier+6,"16") == 0) ? MVT::i16 : MVT::i8));
       Reg = getX86SubSuperRegister(Reg, VT);
     }
-    for (const char *Name = RI.get(Reg).AsmName; *Name; ++Name)
+    for (const char *Name = TRI->getAsmName(Reg); *Name; ++Name)
       O << (char)tolower(*Name);
     return;
   }
@@ -548,7 +547,6 @@ void X86ATTAsmPrinter::printPICJumpTableEntry(const MachineJumpTableInfo *MJTI,
 
 bool X86ATTAsmPrinter::printAsmMRegister(const MachineOperand &MO,
                                          const char Mode) {
-  const TargetRegisterInfo &RI = *TM.getRegisterInfo();
   unsigned Reg = MO.getReg();
   switch (Mode) {
   default: return true;  // Unknown mode.
@@ -570,7 +568,7 @@ bool X86ATTAsmPrinter::printAsmMRegister(const MachineOperand &MO,
   }
 
   O << '%';
-  for (const char *Name = RI.get(Reg).AsmName; *Name; ++Name)
+  for (const char *Name = TRI->getAsmName(Reg); *Name; ++Name)
     O << (char)tolower(*Name);
   return false;
 }
diff --git a/lib/Target/X86/X86CodeEmitter.cpp b/lib/Target/X86/X86CodeEmitter.cpp
index 33b87be50d2..87481c7d7f1 100644
--- a/lib/Target/X86/X86CodeEmitter.cpp
+++ b/lib/Target/X86/X86CodeEmitter.cpp
@@ -623,14 +623,6 @@ void Emitter::emitInstruction(const MachineInstr &MI,
       break;
     case TargetInstrInfo::DECLARE:
     case X86::DWARF_LOC:
-    case X86::IMPLICIT_DEF_GR8:
-    case X86::IMPLICIT_DEF_GR16:
-    case X86::IMPLICIT_DEF_GR32:
-    case X86::IMPLICIT_DEF_GR64:
-    case X86::IMPLICIT_DEF_FR32:
-    case X86::IMPLICIT_DEF_FR64:
-    case X86::IMPLICIT_DEF_VR64:
-    case X86::IMPLICIT_DEF_VR128:
     case X86::FP_REG_KILL:
       break;
     case X86::MOVPC32r: {
diff --git a/lib/Target/X86/X86Instr64bit.td b/lib/Target/X86/X86Instr64bit.td
index f3c873e4db2..730f3930bf4 100644
--- a/lib/Target/X86/X86Instr64bit.td
+++ b/lib/Target/X86/X86Instr64bit.td
@@ -86,11 +86,6 @@ def extloadi64i32  : PatFrag<(ops node:$ptr), (i64 (extloadi32 node:$ptr))>;
 // Instruction list...
 //
 
-let isImplicitDef = 1 in
-def IMPLICIT_DEF_GR64  : I<0, Pseudo, (outs GR64:$dst), (ins),
-                         "#IMPLICIT_DEF $dst",
-                         [(set GR64:$dst, (undef))]>;
-
 //===----------------------------------------------------------------------===//
 //  Call Instructions...
 //
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index e32fb9c4b53..9c034644f1a 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -279,17 +279,6 @@ def ADJCALLSTACKUP   : I<0, Pseudo, (outs), (ins i32imm:$amt1, i32imm:$amt2),
                          "#ADJCALLSTACKUP",
                          [(X86callseq_end imm:$amt1, imm:$amt2)]>;
 }
-let isImplicitDef = 1 in {
-def IMPLICIT_DEF_GR8  : I<0, Pseudo, (outs GR8:$dst), (ins),
-                         "#IMPLICIT_DEF $dst",
-                         [(set GR8:$dst, (undef))]>;
-def IMPLICIT_DEF_GR16  : I<0, Pseudo, (outs GR16:$dst), (ins),
-                         "#IMPLICIT_DEF $dst",
-                         [(set GR16:$dst, (undef))]>;
-def IMPLICIT_DEF_GR32  : I<0, Pseudo, (outs GR32:$dst), (ins),
-                         "#IMPLICIT_DEF $dst",
-                         [(set GR32:$dst, (undef))]>;
-}
 
 // Nop
 let neverHasSideEffects = 1 in
diff --git a/lib/Target/X86/X86InstrMMX.td b/lib/Target/X86/X86InstrMMX.td
index 0a18fa53f1e..3d8bd1f579c 100644
--- a/lib/Target/X86/X86InstrMMX.td
+++ b/lib/Target/X86/X86InstrMMX.td
@@ -13,19 +13,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Some 'special' instructions
-let isImplicitDef = 1 in
-def IMPLICIT_DEF_VR64 : I<0, Pseudo, (outs VR64:$dst), (ins),
-                          "#IMPLICIT_DEF $dst",
-                          [(set VR64:$dst, (v8i8 (undef)))]>,
-                        Requires<[HasMMX]>;
-
-// 64-bit vector undef's.
-def : Pat<(v8i8  (undef)), (IMPLICIT_DEF_VR64)>;
-def : Pat<(v4i16 (undef)), (IMPLICIT_DEF_VR64)>;
-def : Pat<(v2i32 (undef)), (IMPLICIT_DEF_VR64)>;
-def : Pat<(v1i64 (undef)), (IMPLICIT_DEF_VR64)>;
-
 //===----------------------------------------------------------------------===//
 // MMX Pattern Fragments
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/X86/X86InstrSSE.td b/lib/Target/X86/X86InstrSSE.td
index 9b632e472ba..ff19dc02cc2 100644
--- a/lib/Target/X86/X86InstrSSE.td
+++ b/lib/Target/X86/X86InstrSSE.td
@@ -48,23 +48,6 @@ def X86insrtps : SDNode<"X86ISD::INSERTPS",
                  SDTypeProfile<1, 3, [SDTCisVT<0, v4f32>, SDTCisSameAs<0,1>,
                                       SDTCisVT<2, f32>, SDTCisPtrTy<3>]>>;
 
-//===----------------------------------------------------------------------===//
-// SSE 'Special' Instructions
-//===----------------------------------------------------------------------===//
-
-let isImplicitDef = 1 in {
-def IMPLICIT_DEF_VR128 : I<0, Pseudo, (outs VR128:$dst), (ins),
-                           "#IMPLICIT_DEF $dst",
-                           [(set VR128:$dst, (v4f32 (undef)))]>,
-                         Requires<[HasSSE1]>;
-def IMPLICIT_DEF_FR32  : I<0, Pseudo, (outs FR32:$dst), (ins),
-                           "#IMPLICIT_DEF $dst",
-                           [(set FR32:$dst, (undef))]>, Requires<[HasSSE1]>;
-def IMPLICIT_DEF_FR64  : I<0, Pseudo, (outs FR64:$dst), (ins),
-                           "#IMPLICIT_DEF $dst",
-                           [(set FR64:$dst, (undef))]>, Requires<[HasSSE2]>;
-}
-
 //===----------------------------------------------------------------------===//
 // SSE Complex Patterns
 //===----------------------------------------------------------------------===//
@@ -2754,14 +2737,6 @@ let Constraints = "$src1 = $dst" in {
 // Non-Instruction Patterns
 //===----------------------------------------------------------------------===//
 
-// 128-bit vector undef's.
-def : Pat<(v4f32 (undef)), (IMPLICIT_DEF_VR128)>, Requires<[HasSSE2]>;
-def : Pat<(v2f64 (undef)), (IMPLICIT_DEF_VR128)>, Requires<[HasSSE2]>;
-def : Pat<(v16i8 (undef)), (IMPLICIT_DEF_VR128)>, Requires<[HasSSE2]>;
-def : Pat<(v8i16 (undef)), (IMPLICIT_DEF_VR128)>, Requires<[HasSSE2]>;
-def : Pat<(v4i32 (undef)), (IMPLICIT_DEF_VR128)>, Requires<[HasSSE2]>;
-def : Pat<(v2i64 (undef)), (IMPLICIT_DEF_VR128)>, Requires<[HasSSE2]>;
-
 // extload f32 -> f64.  This matches load+fextend because we have a hack in 
 // the isel (PreprocessForFPConvert) that can introduce loads after dag combine.
 // Since these loads aren't folded into the fextend, we have to match it
diff --git a/lib/Target/X86/X86IntelAsmPrinter.cpp b/lib/Target/X86/X86IntelAsmPrinter.cpp
index 16d819a3d7c..0caab87dd03 100644
--- a/lib/Target/X86/X86IntelAsmPrinter.cpp
+++ b/lib/Target/X86/X86IntelAsmPrinter.cpp
@@ -114,7 +114,6 @@ void X86IntelAsmPrinter::printSSECC(const MachineInstr *MI, unsigned Op) {
 
 void X86IntelAsmPrinter::printOp(const MachineOperand &MO, 
                                  const char *Modifier) {
-  const TargetRegisterInfo &RI = *TM.getRegisterInfo();
   switch (MO.getType()) {
   case MachineOperand::MO_Register: {      
     if (TargetRegisterInfo::isPhysicalRegister(MO.getReg())) {
@@ -125,7 +124,7 @@ void X86IntelAsmPrinter::printOp(const MachineOperand &MO,
                       ((strcmp(Modifier,"subreg16") == 0) ? MVT::i16 :MVT::i8));
         Reg = getX86SubSuperRegister(Reg, VT);
       }
-      O << RI.get(Reg).AsmName;
+      O << TRI->getAsmName(Reg);
     } else
       O << "reg" << MO.getReg();
     return;
@@ -253,7 +252,6 @@ void X86IntelAsmPrinter::printPICLabel(const MachineInstr *MI, unsigned Op) {
 
 bool X86IntelAsmPrinter::printAsmMRegister(const MachineOperand &MO,
                                            const char Mode) {
-  const TargetRegisterInfo &RI = *TM.getRegisterInfo();
   unsigned Reg = MO.getReg();
   switch (Mode) {
   default: return true;  // Unknown mode.
@@ -271,7 +269,7 @@ bool X86IntelAsmPrinter::printAsmMRegister(const MachineOperand &MO,
     break;
   }
 
-  O << '%' << RI.get(Reg).AsmName;
+  O << '%' << TRI->getAsmName(Reg);
   return false;
 }
 
diff --git a/utils/TableGen/AsmWriterEmitter.cpp b/utils/TableGen/AsmWriterEmitter.cpp
index 5a24b26422e..08f2eb20b3e 100644
--- a/utils/TableGen/AsmWriterEmitter.cpp
+++ b/utils/TableGen/AsmWriterEmitter.cpp
@@ -630,6 +630,9 @@ void AsmWriterEmitter::run(std::ostream &O) {
     << "  } else if (MI->getOpcode() == TargetInstrInfo::DECLARE) {\n"
     << "    printDeclare(MI);\n"
     << "    return true;\n"
+    << "  } else if (MI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF) {\n"
+    << "    printImplicitDef(MI);\n"
+    << "    return true;\n"
     << "  }\n\n";
   
   O << "  O << \"\\t\";\n\n";
diff --git a/utils/TableGen/CodeEmitterGen.cpp b/utils/TableGen/CodeEmitterGen.cpp
index 60d196cb4aa..bebf1fd56b8 100644
--- a/utils/TableGen/CodeEmitterGen.cpp
+++ b/utils/TableGen/CodeEmitterGen.cpp
@@ -29,7 +29,8 @@ void CodeEmitterGen::reverseBits(std::vector<Record*> &Insts) {
         R->getName() == "LABEL" ||
         R->getName() == "DECLARE" ||
         R->getName() == "EXTRACT_SUBREG" ||
-        R->getName() == "INSERT_SUBREG") continue;
+        R->getName() == "INSERT_SUBREG" ||
+        R->getName() == "IMPLICIT_DEF") continue;
     
     BitsInit *BI = R->getValueAsBitsInit("Inst");
 
@@ -103,7 +104,8 @@ void CodeEmitterGen::run(std::ostream &o) {
         R->getName() == "LABEL" ||
         R->getName() == "DECLARE" ||
         R->getName() == "EXTRACT_SUBREG" ||
-        R->getName() == "INSERT_SUBREG") {
+        R->getName() == "INSERT_SUBREG" ||
+        R->getName() == "IMPLICIT_DEF") {
       o << "    0U";
       continue;
     }
@@ -136,7 +138,8 @@ void CodeEmitterGen::run(std::ostream &o) {
         InstName == "LABEL"||
         InstName == "DECLARE"||
         InstName == "EXTRACT_SUBREG" ||
-        InstName == "INSERT_SUBREG") continue;
+        InstName == "INSERT_SUBREG" ||
+        InstName == "IMPLICIT_DEF") continue;
     
     BitsInit *BI = R->getValueAsBitsInit("Inst");
     const std::vector<RecordVal> &Vals = R->getValues();
diff --git a/utils/TableGen/CodeGenTarget.cpp b/utils/TableGen/CodeGenTarget.cpp
index b9730a5bd90..e41f75a68ab 100644
--- a/utils/TableGen/CodeGenTarget.cpp
+++ b/utils/TableGen/CodeGenTarget.cpp
@@ -304,6 +304,11 @@ getInstructionsByEnumValue(std::vector<const CodeGenInstruction*>
     throw "Could not find 'INSERT_SUBREG' instruction!";
   const CodeGenInstruction *INSERT_SUBREG = &I->second;
   
+  I = getInstructions().find("IMPLICIT_DEF");
+  if (I == Instructions.end())
+    throw "Could not find 'IMPLICIT_DEF' instruction!";
+  const CodeGenInstruction *IMPLICIT_DEF = &I->second;
+  
   // Print out the rest of the instructions now.
   NumberedInstructions.push_back(PHI);
   NumberedInstructions.push_back(INLINEASM);
@@ -311,13 +316,15 @@ getInstructionsByEnumValue(std::vector<const CodeGenInstruction*>
   NumberedInstructions.push_back(DECLARE);
   NumberedInstructions.push_back(EXTRACT_SUBREG);
   NumberedInstructions.push_back(INSERT_SUBREG);
+  NumberedInstructions.push_back(IMPLICIT_DEF);
   for (inst_iterator II = inst_begin(), E = inst_end(); II != E; ++II)
     if (&II->second != PHI &&
         &II->second != INLINEASM &&
         &II->second != LABEL &&
         &II->second != DECLARE &&
         &II->second != EXTRACT_SUBREG &&
-        &II->second != INSERT_SUBREG)
+        &II->second != INSERT_SUBREG &&
+        &II->second != IMPLICIT_DEF)
       NumberedInstructions.push_back(&II->second);
 }
 
diff --git a/utils/TableGen/DAGISelEmitter.cpp b/utils/TableGen/DAGISelEmitter.cpp
index 0c6afab4c99..dc95e7981fd 100644
--- a/utils/TableGen/DAGISelEmitter.cpp
+++ b/utils/TableGen/DAGISelEmitter.cpp
@@ -1825,7 +1825,12 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
                  "Ops.size());\n"
      << "  return New.Val;\n"
      << "}\n\n";
-  
+
+  OS << "SDNode *Select_UNDEF(const SDOperand &N) {\n"
+     << "  return CurDAG->getTargetNode(TargetInstrInfo::IMPLICIT_DEF,\n"
+     << "                               N.getValueType());\n"
+     << "}\n\n";
+
   OS << "SDNode *Select_LABEL(const SDOperand &N) {\n"
      << "  SDOperand Chain = N.getOperand(0);\n"
      << "  SDOperand N1 = N.getOperand(1);\n"
@@ -1926,7 +1931,8 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
      << "  case ISD::LABEL: return Select_LABEL(N);\n"
      << "  case ISD::DECLARE: return Select_DECLARE(N);\n"
      << "  case ISD::EXTRACT_SUBREG: return Select_EXTRACT_SUBREG(N);\n"
-     << "  case ISD::INSERT_SUBREG:  return Select_INSERT_SUBREG(N);\n";
+     << "  case ISD::INSERT_SUBREG: return Select_INSERT_SUBREG(N);\n"
+     << "  case ISD::UNDEF: return Select_UNDEF(N);\n";
 
     
   // Loop over all of the case statements, emiting a call to each method we
diff --git a/utils/TableGen/InstrInfoEmitter.cpp b/utils/TableGen/InstrInfoEmitter.cpp
index 3be36266f70..2ac76349d70 100644
--- a/utils/TableGen/InstrInfoEmitter.cpp
+++ b/utils/TableGen/InstrInfoEmitter.cpp
@@ -411,7 +411,8 @@ void InstrInfoEmitter::emitShiftedValue(Record *R, StringInit *Val,
         R->getName() != "LABEL" &&
         R->getName() != "DECLARE" &&
         R->getName() != "EXTRACT_SUBREG" &&
-        R->getName() != "INSERT_SUBREG")
+        R->getName() != "INSERT_SUBREG" &&
+        R->getName() != "IMPLICIT_DEF")
       throw R->getName() + " doesn't have a field named '" + 
             Val->getValue() + "'!";
     return;