diff --git a/lib/Target/X86/InstSelectPattern.cpp b/lib/Target/X86/InstSelectPattern.cpp
new file mode 100644
index 0000000..4b9e381
--- /dev/null
+++ b/lib/Target/X86/InstSelectPattern.cpp
@@ -0,0 +1,117 @@
+//===-- InstSelectPattern.cpp - A pattern matching inst selector for X86 --===//
+//
+// This file defines a pattern matching instruction selector for X86.
+//
+//  FIXME: we could allocate one big array of unsigneds to use as the backing
+//         store for all of the nodes costs arrays.
+//
+//===----------------------------------------------------------------------===//
+
+#include "X86.h"
+#include "llvm/Pass.h"
+#include "llvm/Function.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/SSARegMap.h"
+
+#include "X86RegisterInfo.h"
+
+// Include the generated instruction selector...
+#include "X86GenInstrSelector.inc"
+
+
+//===----------------------------------------------------------------------===//
+//  User code
+//
+
+
+namespace {
+  struct ISel : public FunctionPass, SelectionDAGTargetBuilder {
+    TargetMachine &TM;
+    ISel(TargetMachine &tm) : TM(tm) {}
+    int VarArgsFrameIndex;              // FrameIndex for start of varargs area
+
+    bool runOnFunction(Function &Fn) {
+      MachineFunction &MF = MachineFunction::construct(&Fn, TM);
+      SelectionDAG DAG(MF, TM, *this);
+
+      std::cerr << "\n\n\n=== "
+                << DAG.getMachineFunction().getFunction()->getName() << "\n";
+
+      DAG.dump();
+      X86ISel(DAG).generateCode();
+      std::cerr << "\n\n\n";
+      return true;
+    }
+
+  public:  // Implementation of the SelectionDAGTargetBuilder class...
+    /// expandArguments - Add nodes to the DAG to indicate how to load arguments
+    /// off of the X86 stack.
+    void expandArguments(SelectionDAG &SD, MachineFunction &MF);
+  };
+}
+
+
+void ISel::expandArguments(SelectionDAG &SD, MachineFunction &F) {
+  // Add DAG nodes to load the arguments...  On entry to a function on the X86,
+  // the stack frame looks like this:
+  //
+  // [ESP] -- return address
+  // [ESP + 4] -- first argument (leftmost lexically)
+  // [ESP + 8] -- second argument, if first argument is four bytes in size
+  //    ... 
+  //
+  unsigned ArgOffset = 0;   // Frame mechanisms handle retaddr slot
+  MachineFrameInfo *MFI = F.getFrameInfo();
+  const Function &Fn = *F.getFunction();
+  
+  for (Function::const_aiterator I = Fn.abegin(), E = Fn.aend(); I != E; ++I) {
+    MVT::ValueType ObjectVT = SD.getValueType(I->getType());
+    unsigned ArgIncrement = 4;
+    unsigned ObjSize;
+    switch (ObjectVT) {
+    default: assert(0 && "Unhandled argument type!");
+    case MVT::i8:  ObjSize = 1;                break;
+    case MVT::i16: ObjSize = 2;                break;
+    case MVT::i32: ObjSize = 4;                break;
+    case MVT::i64: ObjSize = ArgIncrement = 8; break;
+    case MVT::f32: ObjSize = 4;                break;
+    case MVT::f64: ObjSize = ArgIncrement = 8; break;
+    }
+    // Create the frame index object for this incoming parameter...
+    int FI = MFI->CreateFixedObject(ObjSize, ArgOffset);
+    
+    // Create the SelectionDAG nodes corresponding to a load from this parameter
+    // FIXME:
+    SelectionDAGNode *FIN = new SelectionDAGNode(ISD::FrameIndex, MVT::i32);
+    FIN->addValue(new ReducedValue_FrameIndex_i32(FI));
+
+    SelectionDAGNode *Arg
+      = new SelectionDAGNode(ISD::Load, ObjectVT, F.begin(), FIN);
+
+    // Add the SelectionDAGNodes to the SelectionDAG... note that there is no
+    // reason to add chain nodes here.  We know that no loads ore stores will
+    // ever alias these loads, so we are free to perform the load at any time in
+    // the function
+    SD.addNode(FIN);
+    SD.addNodeForValue(Arg, I);
+
+    ArgOffset += ArgIncrement;   // Move on to the next argument...
+  }
+
+  // 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.
+  if (Fn.getFunctionType()->isVarArg())
+    VarArgsFrameIndex = MFI->CreateFixedObject(1, ArgOffset);
+}
+
+
+/// createX86PatternInstructionSelector - This pass converts an LLVM function
+/// into a machine code representation using pattern matching and a machine
+/// description file.
+///
+Pass *createX86PatternInstructionSelector(TargetMachine &TM) {
+  return new ISel(TM);  
+}
diff --git a/lib/Target/X86/Makefile b/lib/Target/X86/Makefile
index ff4ab7c..ee4cf8c 100644
--- a/lib/Target/X86/Makefile
+++ b/lib/Target/X86/Makefile
@@ -5,22 +5,25 @@
 # Make sure that tblgen is run, first thing.
 $(SourceDepend): X86GenRegisterInfo.h.inc X86GenRegisterNames.inc \
                  X86GenRegisterInfo.inc X86GenInstrNames.inc \
-                 X86GenInstrInfo.inc
+                 X86GenInstrInfo.inc X86GenInstrSelector.inc
 
-X86GenRegisterNames.inc:  X86.td X86RegisterInfo.td $(TBLGEN)
-	$(TBLGEN) X86.td -gen-register-enums -o $@
+X86GenRegisterNames.inc:  X86.td X86RegisterInfo.td ../Target.td $(TBLGEN)
+	$(TBLGEN) $< -gen-register-enums -o $@
 
-X86GenRegisterInfo.h.inc: X86.td X86RegisterInfo.td $(TBLGEN)
-	$(TBLGEN) X86.td -gen-register-desc-header -o $@
+X86GenRegisterInfo.h.inc: X86.td X86RegisterInfo.td ../Target.td $(TBLGEN)
+	$(TBLGEN) $< -gen-register-desc-header -o $@
 
-X86GenRegisterInfo.inc: X86.td X86RegisterInfo.td $(TBLGEN)
-	$(TBLGEN) X86.td -gen-register-desc -o $@
+X86GenRegisterInfo.inc: X86.td X86RegisterInfo.td ../Target.td $(TBLGEN)
+	$(TBLGEN) $< -gen-register-desc -o $@
 
-X86GenInstrNames.inc: X86.td X86InstrInfo.td $(TBLGEN)
-	$(TBLGEN) X86.td -gen-instr-enums -o $@
+X86GenInstrNames.inc: X86.td X86InstrInfo.td ../Target.td $(TBLGEN)
+	$(TBLGEN) $< -gen-instr-enums -o $@
 
-X86GenInstrInfo.inc: X86.td X86InstrInfo.td $(TBLGEN)
-	$(TBLGEN) X86.td -gen-instr-desc -o $@
+X86GenInstrInfo.inc: X86.td X86InstrInfo.td ../Target.td $(TBLGEN)
+	$(TBLGEN) $< -gen-instr-desc -o $@
+
+X86GenInstrSelector.inc: X86.td X86InstrInfo.td ../Target.td $(TBLGEN)
+	$(TBLGEN) $< -gen-instr-selector -o $@
 
 clean::
 	$(VERB) rm -f *.inc
diff --git a/lib/Target/X86/X86.h b/lib/Target/X86/X86.h
index 61d3123..eec254c 100644
--- a/lib/Target/X86/X86.h
+++ b/lib/Target/X86/X86.h
@@ -18,6 +18,12 @@
 ///
 Pass *createX86SimpleInstructionSelector(TargetMachine &TM);
 
+/// createX86PatternInstructionSelector - This pass converts an LLVM function
+/// into a machine code representation using pattern matching and a machine
+/// description file.
+///
+Pass *createX86PatternInstructionSelector(TargetMachine &TM);
+
 /// createX86PeepholeOptimizer - Create a pass to perform X86 specific peephole
 /// optimizations.
 ///
diff --git a/lib/Target/X86/X86ISelPattern.cpp b/lib/Target/X86/X86ISelPattern.cpp
new file mode 100644
index 0000000..4b9e381
--- /dev/null
+++ b/lib/Target/X86/X86ISelPattern.cpp
@@ -0,0 +1,117 @@
+//===-- InstSelectPattern.cpp - A pattern matching inst selector for X86 --===//
+//
+// This file defines a pattern matching instruction selector for X86.
+//
+//  FIXME: we could allocate one big array of unsigneds to use as the backing
+//         store for all of the nodes costs arrays.
+//
+//===----------------------------------------------------------------------===//
+
+#include "X86.h"
+#include "llvm/Pass.h"
+#include "llvm/Function.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/SSARegMap.h"
+
+#include "X86RegisterInfo.h"
+
+// Include the generated instruction selector...
+#include "X86GenInstrSelector.inc"
+
+
+//===----------------------------------------------------------------------===//
+//  User code
+//
+
+
+namespace {
+  struct ISel : public FunctionPass, SelectionDAGTargetBuilder {
+    TargetMachine &TM;
+    ISel(TargetMachine &tm) : TM(tm) {}
+    int VarArgsFrameIndex;              // FrameIndex for start of varargs area
+
+    bool runOnFunction(Function &Fn) {
+      MachineFunction &MF = MachineFunction::construct(&Fn, TM);
+      SelectionDAG DAG(MF, TM, *this);
+
+      std::cerr << "\n\n\n=== "
+                << DAG.getMachineFunction().getFunction()->getName() << "\n";
+
+      DAG.dump();
+      X86ISel(DAG).generateCode();
+      std::cerr << "\n\n\n";
+      return true;
+    }
+
+  public:  // Implementation of the SelectionDAGTargetBuilder class...
+    /// expandArguments - Add nodes to the DAG to indicate how to load arguments
+    /// off of the X86 stack.
+    void expandArguments(SelectionDAG &SD, MachineFunction &MF);
+  };
+}
+
+
+void ISel::expandArguments(SelectionDAG &SD, MachineFunction &F) {
+  // Add DAG nodes to load the arguments...  On entry to a function on the X86,
+  // the stack frame looks like this:
+  //
+  // [ESP] -- return address
+  // [ESP + 4] -- first argument (leftmost lexically)
+  // [ESP + 8] -- second argument, if first argument is four bytes in size
+  //    ... 
+  //
+  unsigned ArgOffset = 0;   // Frame mechanisms handle retaddr slot
+  MachineFrameInfo *MFI = F.getFrameInfo();
+  const Function &Fn = *F.getFunction();
+  
+  for (Function::const_aiterator I = Fn.abegin(), E = Fn.aend(); I != E; ++I) {
+    MVT::ValueType ObjectVT = SD.getValueType(I->getType());
+    unsigned ArgIncrement = 4;
+    unsigned ObjSize;
+    switch (ObjectVT) {
+    default: assert(0 && "Unhandled argument type!");
+    case MVT::i8:  ObjSize = 1;                break;
+    case MVT::i16: ObjSize = 2;                break;
+    case MVT::i32: ObjSize = 4;                break;
+    case MVT::i64: ObjSize = ArgIncrement = 8; break;
+    case MVT::f32: ObjSize = 4;                break;
+    case MVT::f64: ObjSize = ArgIncrement = 8; break;
+    }
+    // Create the frame index object for this incoming parameter...
+    int FI = MFI->CreateFixedObject(ObjSize, ArgOffset);
+    
+    // Create the SelectionDAG nodes corresponding to a load from this parameter
+    // FIXME:
+    SelectionDAGNode *FIN = new SelectionDAGNode(ISD::FrameIndex, MVT::i32);
+    FIN->addValue(new ReducedValue_FrameIndex_i32(FI));
+
+    SelectionDAGNode *Arg
+      = new SelectionDAGNode(ISD::Load, ObjectVT, F.begin(), FIN);
+
+    // Add the SelectionDAGNodes to the SelectionDAG... note that there is no
+    // reason to add chain nodes here.  We know that no loads ore stores will
+    // ever alias these loads, so we are free to perform the load at any time in
+    // the function
+    SD.addNode(FIN);
+    SD.addNodeForValue(Arg, I);
+
+    ArgOffset += ArgIncrement;   // Move on to the next argument...
+  }
+
+  // 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.
+  if (Fn.getFunctionType()->isVarArg())
+    VarArgsFrameIndex = MFI->CreateFixedObject(1, ArgOffset);
+}
+
+
+/// createX86PatternInstructionSelector - This pass converts an LLVM function
+/// into a machine code representation using pattern matching and a machine
+/// description file.
+///
+Pass *createX86PatternInstructionSelector(TargetMachine &TM) {
+  return new ISel(TM);  
+}
diff --git a/lib/Target/X86/X86TargetMachine.cpp b/lib/Target/X86/X86TargetMachine.cpp
index 893e62f..2de30f7 100644
--- a/lib/Target/X86/X86TargetMachine.cpp
+++ b/lib/Target/X86/X86TargetMachine.cpp
@@ -20,6 +20,8 @@
                           cl::desc("Use Simple RA instead of Local RegAlloc"));
   cl::opt<bool> PrintCode("print-machineinstrs",
 			  cl::desc("Print generated machine code"));
+  cl::opt<bool> NoPatternISel("disable-pattern-isel", cl::init(true),
+                        cl::desc("Use the 'simple' X86 instruction selector"));
 }
 
 // allocateX86TargetMachine - Allocate and return a subclass of TargetMachine
@@ -59,7 +61,10 @@
   // FIXME: Implement the switch instruction in the instruction selector!
   PM.add(createLowerSwitchPass());
 
-  PM.add(createX86SimpleInstructionSelector(*this));
+  if (NoPatternISel)
+    PM.add(createX86SimpleInstructionSelector(*this));
+  else
+    PM.add(createX86PatternInstructionSelector(*this));
 
   // TODO: optional optimizations go here