Move support/tools/* back into utils

llvm-svn: 8875
diff --git a/llvm/utils/TableGen/InstrSelectorEmitter.cpp b/llvm/utils/TableGen/InstrSelectorEmitter.cpp
new file mode 100644
index 0000000..a3c535c
--- /dev/null
+++ b/llvm/utils/TableGen/InstrSelectorEmitter.cpp
@@ -0,0 +1,1287 @@
+//===- InstrInfoEmitter.cpp - Generate a Instruction Set Desc. ------------===//
+//
+// This tablegen backend is responsible for emitting a description of the target
+// instruction set for the code generator.
+//
+//===----------------------------------------------------------------------===//
+
+#include "InstrSelectorEmitter.h"
+#include "CodeGenWrappers.h"
+#include "Record.h"
+#include "Support/Debug.h"
+#include "Support/StringExtras.h"
+#include <set>
+
+NodeType::ArgResultTypes NodeType::Translate(Record *R) {
+  const std::string &Name = R->getName();
+  if (Name == "DNVT_any")  return Any;
+  if (Name == "DNVT_void") return Void;
+  if (Name == "DNVT_val" ) return Val;
+  if (Name == "DNVT_arg0") return Arg0;
+  if (Name == "DNVT_arg1") return Arg1;
+  if (Name == "DNVT_ptr" ) return Ptr;
+  if (Name == "DNVT_i8"  ) return I8;
+  throw "Unknown DagNodeValType '" + Name + "'!";
+}
+
+
+//===----------------------------------------------------------------------===//
+// TreePatternNode implementation
+//
+
+/// getValueRecord - Returns the value of this tree node as a record.  For now
+/// we only allow DefInit's as our leaf values, so this is used.
+Record *TreePatternNode::getValueRecord() const {
+  DefInit *DI = dynamic_cast<DefInit*>(getValue());
+  assert(DI && "Instruction Selector does not yet support non-def leaves!");
+  return DI->getDef();
+}
+
+
+// updateNodeType - Set the node type of N to VT if VT contains information.  If
+// N already contains a conflicting type, then throw an exception
+//
+bool TreePatternNode::updateNodeType(MVT::ValueType VT,
+                                     const std::string &RecName) {
+  if (VT == MVT::Other || getType() == VT) return false;
+  if (getType() == MVT::Other) {
+    setType(VT);
+    return true;
+  }
+
+  throw "Type inferfence contradiction found for pattern " + RecName;
+}
+
+/// InstantiateNonterminals - If this pattern refers to any nonterminals which
+/// are not themselves completely resolved, clone the nonterminal and resolve it
+/// with the using context we provide.
+///
+void TreePatternNode::InstantiateNonterminals(InstrSelectorEmitter &ISE) {
+  if (!isLeaf()) {
+    for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
+      getChild(i)->InstantiateNonterminals(ISE);
+    return;
+  }
+  
+  // If this is a leaf, it might be a reference to a nonterminal!  Check now.
+  Record *R = getValueRecord();
+  if (R->isSubClassOf("Nonterminal")) {
+    Pattern *NT = ISE.getPattern(R);
+    if (!NT->isResolved()) {
+      // We found an unresolved nonterminal reference.  Ask the ISE to clone
+      // it for us, then update our reference to the fresh, new, resolved,
+      // nonterminal.
+      
+      Value = new DefInit(ISE.InstantiateNonterminal(NT, getType()));
+    }
+  }
+}
+
+
+/// clone - Make a copy of this tree and all of its children.
+///
+TreePatternNode *TreePatternNode::clone() const {
+  TreePatternNode *New;
+  if (isLeaf()) {
+    New = new TreePatternNode(Value);
+  } else {
+    std::vector<std::pair<TreePatternNode*, std::string> > CChildren;
+    CChildren.reserve(Children.size());
+    for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
+      CChildren.push_back(std::make_pair(getChild(i)->clone(),getChildName(i)));
+    New = new TreePatternNode(Operator, CChildren);
+  }
+  New->setType(Type);
+  return New;
+}
+
+std::ostream &operator<<(std::ostream &OS, const TreePatternNode &N) {
+  if (N.isLeaf())
+    return OS << N.getType() << ":" << *N.getValue();
+  OS << "(" << N.getType() << ":";
+  OS << N.getOperator()->getName();
+  
+  if (N.getNumChildren() != 0) {
+    OS << " " << *N.getChild(0);
+    for (unsigned i = 1, e = N.getNumChildren(); i != e; ++i)
+      OS << ", " << *N.getChild(i);
+  }  
+  return OS << ")";
+}
+
+void TreePatternNode::dump() const { std::cerr << *this; }
+
+//===----------------------------------------------------------------------===//
+// Pattern implementation
+//
+
+// Parse the specified DagInit into a TreePattern which we can use.
+//
+Pattern::Pattern(PatternType pty, DagInit *RawPat, Record *TheRec,
+                 InstrSelectorEmitter &ise)
+  : PTy(pty), ResultNode(0), TheRecord(TheRec), ISE(ise) {
+
+  // First, parse the pattern...
+  Tree = ParseTreePattern(RawPat);
+
+  // Run the type-inference engine...
+  InferAllTypes();
+
+  if (PTy == Instruction || PTy == Expander) {
+    // Check to make sure there is not any unset types in the tree pattern...
+    if (!isResolved()) {
+      std::cerr << "In pattern: " << *Tree << "\n";
+      error("Could not infer all types!");
+    }
+
+    // Check to see if we have a top-level (set) of a register.
+    if (Tree->getOperator()->getName() == "set") {
+      assert(Tree->getNumChildren() == 2 && "Set with != 2 arguments?");
+      if (!Tree->getChild(0)->isLeaf())
+        error("Arg #0 of set should be a register or register class!");
+      ResultNode = Tree->getChild(0);
+      ResultName = Tree->getChildName(0);
+      Tree = Tree->getChild(1);
+    }
+  }
+
+  calculateArgs(Tree, "");
+}
+
+void Pattern::error(const std::string &Msg) const {
+  std::string M = "In ";
+  switch (PTy) {
+  case Nonterminal: M += "nonterminal "; break;
+  case Instruction: M += "instruction "; break;
+  case Expander   : M += "expander "; break;
+  }
+  throw M + TheRecord->getName() + ": " + Msg;  
+}
+
+/// calculateArgs - Compute the list of all of the arguments to this pattern,
+/// which are the non-void leaf nodes in this pattern.
+///
+void Pattern::calculateArgs(TreePatternNode *N, const std::string &Name) {
+  if (N->isLeaf() || N->getNumChildren() == 0) {
+    if (N->getType() != MVT::isVoid)
+      Args.push_back(std::make_pair(N, Name));
+  } else {
+    for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i)
+      calculateArgs(N->getChild(i), N->getChildName(i));
+  }
+}
+
+/// getIntrinsicType - Check to see if the specified record has an intrinsic
+/// type which should be applied to it.  This infer the type of register
+/// references from the register file information, for example.
+///
+MVT::ValueType Pattern::getIntrinsicType(Record *R) const {
+  // Check to see if this is a register or a register class...
+  if (R->isSubClassOf("RegisterClass"))
+    return getValueType(R->getValueAsDef("RegType"));
+  else if (R->isSubClassOf("Nonterminal"))
+    return ISE.ReadNonterminal(R)->getTree()->getType();
+  else if (R->isSubClassOf("Register")) {
+    std::cerr << "WARNING: Explicit registers not handled yet!\n";
+    return MVT::Other;
+  }
+
+  error("Unknown value used: " + R->getName());
+  return MVT::Other;
+}
+
+TreePatternNode *Pattern::ParseTreePattern(DagInit *Dag) {
+  Record *Operator = Dag->getNodeType();
+
+  if (Operator->isSubClassOf("ValueType")) {
+    // If the operator is a ValueType, then this must be "type cast" of a leaf
+    // node.
+    if (Dag->getNumArgs() != 1)
+      error("Type cast only valid for a leaf node!");
+    
+    Init *Arg = Dag->getArg(0);
+    TreePatternNode *New;
+    if (DefInit *DI = dynamic_cast<DefInit*>(Arg)) {
+      New = new TreePatternNode(DI);
+      // If it's a regclass or something else known, set the type.
+      New->setType(getIntrinsicType(DI->getDef()));
+    } else if (DagInit *DI = dynamic_cast<DagInit*>(Arg)) {
+      New = ParseTreePattern(DI);
+    } else {
+      Arg->dump();
+      error("Unknown leaf value for tree pattern!");
+      return 0;
+    }
+
+    // Apply the type cast...
+    New->updateNodeType(getValueType(Operator), TheRecord->getName());
+    return New;
+  }
+
+  if (!ISE.getNodeTypes().count(Operator))
+    error("Unrecognized node '" + Operator->getName() + "'!");
+
+  std::vector<std::pair<TreePatternNode*, std::string> > Children;
+  
+  for (unsigned i = 0, e = Dag->getNumArgs(); i != e; ++i) {
+    Init *Arg = Dag->getArg(i);
+    if (DagInit *DI = dynamic_cast<DagInit*>(Arg)) {
+      Children.push_back(std::make_pair(ParseTreePattern(DI),
+                                        Dag->getArgName(i)));
+    } else if (DefInit *DefI = dynamic_cast<DefInit*>(Arg)) {
+      Record *R = DefI->getDef();
+      // Direct reference to a leaf DagNode?  Turn it into a DagNode if its own.
+      if (R->isSubClassOf("DagNode")) {
+        Dag->setArg(i, new DagInit(R,
+                                std::vector<std::pair<Init*, std::string> >()));
+        --i;  // Revisit this node...
+      } else {
+        Children.push_back(std::make_pair(new TreePatternNode(DefI),
+                                          Dag->getArgName(i)));
+        // If it's a regclass or something else known, set the type.
+        Children.back().first->setType(getIntrinsicType(R));
+      }
+    } else {
+      Arg->dump();
+      error("Unknown leaf value for tree pattern!");
+    }
+  }
+
+  return new TreePatternNode(Operator, Children);
+}
+
+void Pattern::InferAllTypes() {
+  bool MadeChange, AnyUnset;
+  do {
+    MadeChange = false;
+    AnyUnset = InferTypes(Tree, MadeChange);
+  } while ((AnyUnset || MadeChange) && !(AnyUnset && !MadeChange));
+  Resolved = !AnyUnset;
+}
+
+
+// InferTypes - Perform type inference on the tree, returning true if there
+// are any remaining untyped nodes and setting MadeChange if any changes were
+// made.
+bool Pattern::InferTypes(TreePatternNode *N, bool &MadeChange) {
+  if (N->isLeaf()) return N->getType() == MVT::Other;
+
+  bool AnyUnset = false;
+  Record *Operator = N->getOperator();
+  const NodeType &NT = ISE.getNodeType(Operator);
+
+  // Check to see if we can infer anything about the argument types from the
+  // return types...
+  if (N->getNumChildren() != NT.ArgTypes.size())
+    error("Incorrect number of children for " + Operator->getName() + " node!");
+
+  for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i) {
+    TreePatternNode *Child = N->getChild(i);
+    AnyUnset |= InferTypes(Child, MadeChange);
+
+    switch (NT.ArgTypes[i]) {
+    case NodeType::Any: break;
+    case NodeType::I8:
+      MadeChange |= Child->updateNodeType(MVT::i1, TheRecord->getName());
+      break;
+    case NodeType::Arg0:
+      MadeChange |= Child->updateNodeType(N->getChild(0)->getType(),
+                                          TheRecord->getName());
+      break;
+    case NodeType::Arg1:
+      MadeChange |= Child->updateNodeType(N->getChild(1)->getType(),
+                                          TheRecord->getName());
+      break;
+    case NodeType::Val:
+      if (Child->getType() == MVT::isVoid)
+        error("Inferred a void node in an illegal place!");
+      break;
+    case NodeType::Ptr:
+      MadeChange |= Child->updateNodeType(ISE.getTarget().getPointerType(),
+                                          TheRecord->getName());
+      break;
+    case NodeType::Void:
+      MadeChange |= Child->updateNodeType(MVT::isVoid, TheRecord->getName());
+      break;
+    default: assert(0 && "Invalid argument ArgType!");
+    }
+  }
+
+  // See if we can infer anything about the return type now...
+  switch (NT.ResultType) {
+  case NodeType::Any: break;
+  case NodeType::Void:
+    MadeChange |= N->updateNodeType(MVT::isVoid, TheRecord->getName());
+    break;
+  case NodeType::I8:
+    MadeChange |= N->updateNodeType(MVT::i1, TheRecord->getName());
+    break;
+  case NodeType::Arg0:
+    MadeChange |= N->updateNodeType(N->getChild(0)->getType(),
+                                    TheRecord->getName());
+    break;
+  case NodeType::Arg1:
+    MadeChange |= N->updateNodeType(N->getChild(1)->getType(),
+                                    TheRecord->getName());
+    break;
+  case NodeType::Ptr:
+    MadeChange |= N->updateNodeType(ISE.getTarget().getPointerType(),
+                                    TheRecord->getName());
+    break;
+  case NodeType::Val:
+    if (N->getType() == MVT::isVoid)
+      error("Inferred a void node in an illegal place!");
+    break;
+  default:
+    assert(0 && "Unhandled type constraint!");
+    break;
+  }
+
+  return AnyUnset | N->getType() == MVT::Other;
+}
+
+/// clone - This method is used to make an exact copy of the current pattern,
+/// then change the "TheRecord" instance variable to the specified record.
+///
+Pattern *Pattern::clone(Record *R) const {
+  assert(PTy == Nonterminal && "Can only clone nonterminals");
+  return new Pattern(Tree->clone(), R, Resolved, ISE);
+}
+
+
+
+std::ostream &operator<<(std::ostream &OS, const Pattern &P) {
+  switch (P.getPatternType()) {
+  case Pattern::Nonterminal: OS << "Nonterminal pattern "; break;
+  case Pattern::Instruction: OS << "Instruction pattern "; break;
+  case Pattern::Expander:    OS << "Expander pattern    "; break;
+  }
+
+  OS << P.getRecord()->getName() << ":\t";
+
+  if (Record *Result = P.getResult())
+    OS << Result->getName() << " = ";
+  OS << *P.getTree();
+
+  if (!P.isResolved())
+    OS << " [not completely resolved]";
+  return OS;
+}
+
+void Pattern::dump() const { std::cerr << *this; }
+
+
+
+/// getSlotName - If this is a leaf node, return the slot name that the operand
+/// will update.
+std::string Pattern::getSlotName() const {
+  if (getPatternType() == Pattern::Nonterminal) {
+    // Just use the nonterminal name, which will already include the type if
+    // it has been cloned.
+    return getRecord()->getName();
+  } else {
+    std::string SlotName;
+    if (getResult())
+      SlotName = getResult()->getName()+"_";
+    else
+      SlotName = "Void_";
+    return SlotName + getName(getTree()->getType());
+  }
+}
+
+/// getSlotName - If this is a leaf node, return the slot name that the
+/// operand will update.
+std::string Pattern::getSlotName(Record *R) {
+  if (R->isSubClassOf("Nonterminal")) {
+    // Just use the nonterminal name, which will already include the type if
+    // it has been cloned.
+    return R->getName();
+  } else if (R->isSubClassOf("RegisterClass")) {
+    MVT::ValueType Ty = getValueType(R->getValueAsDef("RegType"));
+    return R->getName() + "_" + getName(Ty);
+  } else {
+    assert(0 && "Don't know how to get a slot name for this!");
+  }
+  return "";
+}
+
+//===----------------------------------------------------------------------===//
+// PatternOrganizer implementation
+//
+
+/// addPattern - Add the specified pattern to the appropriate location in the
+/// collection.
+void PatternOrganizer::addPattern(Pattern *P) {
+  NodesForSlot &Nodes = AllPatterns[P->getSlotName()];
+  if (!P->getTree()->isLeaf())
+    Nodes[P->getTree()->getOperator()].push_back(P);
+  else {
+    // Right now we only support DefInit's with node types...
+    Nodes[P->getTree()->getValueRecord()].push_back(P);
+  }
+}
+
+
+
+//===----------------------------------------------------------------------===//
+// InstrSelectorEmitter implementation
+//
+
+/// ReadNodeTypes - Read in all of the node types in the current RecordKeeper,
+/// turning them into the more accessible NodeTypes data structure.
+///
+void InstrSelectorEmitter::ReadNodeTypes() {
+  std::vector<Record*> Nodes = Records.getAllDerivedDefinitions("DagNode");
+  DEBUG(std::cerr << "Getting node types: ");
+  for (unsigned i = 0, e = Nodes.size(); i != e; ++i) {
+    Record *Node = Nodes[i];
+    
+    // Translate the return type...
+    NodeType::ArgResultTypes RetTy =
+      NodeType::Translate(Node->getValueAsDef("RetType"));
+
+    // Translate the arguments...
+    ListInit *Args = Node->getValueAsListInit("ArgTypes");
+    std::vector<NodeType::ArgResultTypes> ArgTypes;
+
+    for (unsigned a = 0, e = Args->getSize(); a != e; ++a) {
+      if (DefInit *DI = dynamic_cast<DefInit*>(Args->getElement(a)))
+        ArgTypes.push_back(NodeType::Translate(DI->getDef()));
+      else
+        throw "In node " + Node->getName() + ", argument is not a Def!";
+
+      if (a == 0 && ArgTypes.back() == NodeType::Arg0)
+        throw "In node " + Node->getName() + ", arg 0 cannot have type 'arg0'!";
+      if (a == 1 && ArgTypes.back() == NodeType::Arg1)
+        throw "In node " + Node->getName() + ", arg 1 cannot have type 'arg1'!";
+    }
+    if ((RetTy == NodeType::Arg0 && Args->getSize() == 0) ||
+        (RetTy == NodeType::Arg1 && Args->getSize() < 2))
+      throw "In node " + Node->getName() +
+            ", invalid return type for node with this many operands!";
+
+    // Add the node type mapping now...
+    NodeTypes[Node] = NodeType(RetTy, ArgTypes);
+    DEBUG(std::cerr << Node->getName() << ", ");
+  }
+  DEBUG(std::cerr << "DONE!\n");
+}
+
+Pattern *InstrSelectorEmitter::ReadNonterminal(Record *R) {
+  Pattern *&P = Patterns[R];
+  if (P) return P;  // Don't reread it!
+
+  DagInit *DI = R->getValueAsDag("Pattern");
+  P = new Pattern(Pattern::Nonterminal, DI, R, *this);
+  DEBUG(std::cerr << "Parsed " << *P << "\n");
+  return P;
+}
+
+
+// ReadNonTerminals - Read in all nonterminals and incorporate them into our
+// pattern database.
+void InstrSelectorEmitter::ReadNonterminals() {
+  std::vector<Record*> NTs = Records.getAllDerivedDefinitions("Nonterminal");
+  for (unsigned i = 0, e = NTs.size(); i != e; ++i)
+    ReadNonterminal(NTs[i]);
+}
+
+
+/// ReadInstructionPatterns - Read in all subclasses of Instruction, and process
+/// those with a useful Pattern field.
+///
+void InstrSelectorEmitter::ReadInstructionPatterns() {
+  std::vector<Record*> Insts = Records.getAllDerivedDefinitions("Instruction");
+  for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
+    Record *Inst = Insts[i];
+    if (DagInit *DI = dynamic_cast<DagInit*>(Inst->getValueInit("Pattern"))) {
+      Patterns[Inst] = new Pattern(Pattern::Instruction, DI, Inst, *this);
+      DEBUG(std::cerr << "Parsed " << *Patterns[Inst] << "\n");
+    }
+  }
+}
+
+/// ReadExpanderPatterns - Read in all expander patterns...
+///
+void InstrSelectorEmitter::ReadExpanderPatterns() {
+  std::vector<Record*> Expanders = Records.getAllDerivedDefinitions("Expander");
+  for (unsigned i = 0, e = Expanders.size(); i != e; ++i) {
+    Record *Expander = Expanders[i];
+    DagInit *DI = Expander->getValueAsDag("Pattern");
+    Patterns[Expander] = new Pattern(Pattern::Expander, DI, Expander, *this);
+    DEBUG(std::cerr << "Parsed " << *Patterns[Expander] << "\n");
+  }
+}
+
+
+// InstantiateNonterminals - Instantiate any unresolved nonterminals with
+// information from the context that they are used in.
+//
+void InstrSelectorEmitter::InstantiateNonterminals() {
+  DEBUG(std::cerr << "Instantiating nonterminals:\n");
+  for (std::map<Record*, Pattern*>::iterator I = Patterns.begin(),
+         E = Patterns.end(); I != E; ++I)
+    if (I->second->isResolved())
+      I->second->InstantiateNonterminals();
+}
+
+/// InstantiateNonterminal - This method takes the nonterminal specified by
+/// NT, which should not be completely resolved, clones it, applies ResultTy
+/// to its root, then runs the type inference stuff on it.  This should
+/// produce a newly resolved nonterminal, which we make a record for and
+/// return.  To be extra fancy and efficient, this only makes one clone for
+/// each type it is instantiated with.
+Record *InstrSelectorEmitter::InstantiateNonterminal(Pattern *NT,
+                                                     MVT::ValueType ResultTy) {
+  assert(!NT->isResolved() && "Nonterminal is already resolved!");
+
+  // Check to see if we have already instantiated this pair...
+  Record* &Slot = InstantiatedNTs[std::make_pair(NT, ResultTy)];
+  if (Slot) return Slot;
+  
+  Record *New = new Record(NT->getRecord()->getName()+"_"+getName(ResultTy));
+
+  // Copy over the superclasses...
+  const std::vector<Record*> &SCs = NT->getRecord()->getSuperClasses();
+  for (unsigned i = 0, e = SCs.size(); i != e; ++i)
+    New->addSuperClass(SCs[i]);
+
+  DEBUG(std::cerr << "  Nonterminal '" << NT->getRecord()->getName()
+                  << "' for type '" << getName(ResultTy) << "', producing '"
+                  << New->getName() << "'\n");
+
+  // Copy the pattern...
+  Pattern *NewPat = NT->clone(New);
+
+  // Apply the type to the root...
+  NewPat->getTree()->updateNodeType(ResultTy, New->getName());
+
+  // Infer types...
+  NewPat->InferAllTypes();
+
+  // Make sure everything is good to go now...
+  if (!NewPat->isResolved())
+    NewPat->error("Instantiating nonterminal did not resolve all types!");
+
+  // Add the pattern to the patterns map, add the record to the RecordKeeper,
+  // return the new record.
+  Patterns[New] = NewPat;
+  Records.addDef(New);
+  return Slot = New;
+}
+
+// CalculateComputableValues - Fill in the ComputableValues map through
+// analysis of the patterns we are playing with.
+void InstrSelectorEmitter::CalculateComputableValues() {
+  // Loop over all of the patterns, adding them to the ComputableValues map
+  for (std::map<Record*, Pattern*>::iterator I = Patterns.begin(),
+         E = Patterns.end(); I != E; ++I)
+    if (I->second->isResolved()) {
+      // We don't want to add patterns like R32 = R32.  This is a hack working
+      // around a special case of a general problem, but for now we explicitly
+      // forbid these patterns.  They can never match anyway.
+      Pattern *P = I->second;
+      if (!P->getResult() || !P->getTree()->isLeaf() ||
+          P->getResult() != P->getTree()->getValueRecord())
+        ComputableValues.addPattern(P);
+    }
+}
+
+#if 0
+// MoveIdenticalPatterns - Given a tree pattern 'P', move all of the tree
+// patterns which have the same top-level structure as P from the 'From' list to
+// the 'To' list.
+static void MoveIdenticalPatterns(TreePatternNode *P,
+                    std::vector<std::pair<Pattern*, TreePatternNode*> > &From,
+                    std::vector<std::pair<Pattern*, TreePatternNode*> > &To) {
+  assert(!P->isLeaf() && "All leaves are identical!");
+
+  const std::vector<TreePatternNode*> &PChildren = P->getChildren();
+  for (unsigned i = 0; i != From.size(); ++i) {
+    TreePatternNode *N = From[i].second;
+    assert(P->getOperator() == N->getOperator() &&"Differing operators?");
+    assert(PChildren.size() == N->getChildren().size() &&
+           "Nodes with different arity??");
+    bool isDifferent = false;
+    for (unsigned c = 0, e = PChildren.size(); c != e; ++c) {
+      TreePatternNode *PC = PChildren[c];
+      TreePatternNode *NC = N->getChild(c);
+      if (PC->isLeaf() != NC->isLeaf()) {
+        isDifferent = true;
+        break;
+      }
+
+      if (!PC->isLeaf()) {
+        if (PC->getOperator() != NC->getOperator()) {
+          isDifferent = true;
+          break;
+        }
+      } else {  // It's a leaf!
+        if (PC->getValueRecord() != NC->getValueRecord()) {
+          isDifferent = true;
+          break;
+        }
+      }
+    }
+    // If it's the same as the reference one, move it over now...
+    if (!isDifferent) {
+      To.push_back(std::make_pair(From[i].first, N));
+      From.erase(From.begin()+i);
+      --i;   // Don't skip an entry...
+    }
+  }
+}
+#endif
+
+static std::string getNodeName(Record *R) {
+  RecordVal *RV = R->getValue("EnumName");
+  if (RV)
+    if (Init *I = RV->getValue())
+      if (StringInit *SI = dynamic_cast<StringInit*>(I))
+        return SI->getValue();
+  return R->getName();
+}
+
+
+static void EmitPatternPredicates(TreePatternNode *Tree,
+                                  const std::string &VarName, std::ostream &OS){
+  OS << " && " << VarName << "->getNodeType() == ISD::"
+     << getNodeName(Tree->getOperator());
+
+  for (unsigned c = 0, e = Tree->getNumChildren(); c != e; ++c)
+    if (!Tree->getChild(c)->isLeaf())
+      EmitPatternPredicates(Tree->getChild(c),
+                            VarName + "->getUse(" + utostr(c)+")", OS);
+}
+
+static void EmitPatternCosts(TreePatternNode *Tree, const std::string &VarName,
+                             std::ostream &OS) {
+  for (unsigned c = 0, e = Tree->getNumChildren(); c != e; ++c)
+    if (Tree->getChild(c)->isLeaf()) {
+      OS << " + Match_"
+         << Pattern::getSlotName(Tree->getChild(c)->getValueRecord()) << "("
+         << VarName << "->getUse(" << c << "))";
+    } else {
+      EmitPatternCosts(Tree->getChild(c),
+                       VarName + "->getUse(" + utostr(c) + ")", OS);
+    }
+}
+
+
+// EmitMatchCosters - Given a list of patterns, which all have the same root
+// pattern operator, emit an efficient decision tree to decide which one to
+// pick.  This is structured this way to avoid reevaluations of non-obvious
+// subexpressions.
+void InstrSelectorEmitter::EmitMatchCosters(std::ostream &OS,
+           const std::vector<std::pair<Pattern*, TreePatternNode*> > &Patterns,
+                                            const std::string &VarPrefix,
+                                            unsigned IndentAmt) {
+  assert(!Patterns.empty() && "No patterns to emit matchers for!");
+  std::string Indent(IndentAmt, ' ');
+  
+  // Load all of the operands of the root node into scalars for fast access
+  const NodeType &ONT = getNodeType(Patterns[0].second->getOperator());
+  for (unsigned i = 0, e = ONT.ArgTypes.size(); i != e; ++i)
+    OS << Indent << "SelectionDAGNode *" << VarPrefix << "_Op" << i
+       << " = N->getUse(" << i << ");\n";
+
+  // Compute the costs of computing the various nonterminals/registers, which
+  // are directly used at this level.
+  OS << "\n" << Indent << "// Operand matching costs...\n";
+  std::set<std::string> ComputedValues;   // Avoid duplicate computations...
+  for (unsigned i = 0, e = Patterns.size(); i != e; ++i) {
+    TreePatternNode *NParent = Patterns[i].second;
+    for (unsigned c = 0, e = NParent->getNumChildren(); c != e; ++c) {
+      TreePatternNode *N = NParent->getChild(c);
+      if (N->isLeaf()) {
+        Record *VR = N->getValueRecord();
+        const std::string &LeafName = VR->getName();
+        std::string OpName  = VarPrefix + "_Op" + utostr(c);
+        std::string ValName = OpName + "_" + LeafName + "_Cost";
+        if (!ComputedValues.count(ValName)) {
+          OS << Indent << "unsigned " << ValName << " = Match_"
+             << Pattern::getSlotName(VR) << "(" << OpName << ");\n";
+          ComputedValues.insert(ValName);
+        }
+      }
+    }
+  }
+  OS << "\n";
+
+
+  std::string LocCostName = VarPrefix + "_Cost";
+  OS << Indent << "unsigned " << LocCostName << "Min = ~0U >> 1;\n"
+     << Indent << "unsigned " << VarPrefix << "_PatternMin = NoMatchPattern;\n";
+  
+#if 0
+  // Separate out all of the patterns into groups based on what their top-level
+  // signature looks like...
+  std::vector<std::pair<Pattern*, TreePatternNode*> > PatternsLeft(Patterns);
+  while (!PatternsLeft.empty()) {
+    // Process all of the patterns that have the same signature as the last
+    // element...
+    std::vector<std::pair<Pattern*, TreePatternNode*> > Group;
+    MoveIdenticalPatterns(PatternsLeft.back().second, PatternsLeft, Group);
+    assert(!Group.empty() && "Didn't at least pick the source pattern?");
+
+#if 0
+    OS << "PROCESSING GROUP:\n";
+    for (unsigned i = 0, e = Group.size(); i != e; ++i)
+      OS << "  " << *Group[i].first << "\n";
+    OS << "\n\n";
+#endif
+
+    OS << Indent << "{ // ";
+
+    if (Group.size() != 1) {
+      OS << Group.size() << " size group...\n";
+      OS << Indent << "  unsigned " << VarPrefix << "_Pattern = NoMatch;\n";
+    } else {
+      OS << *Group[0].first << "\n";
+      OS << Indent << "  unsigned " << VarPrefix << "_Pattern = "
+         << Group[0].first->getRecord()->getName() << "_Pattern;\n";
+    }
+
+    OS << Indent << "  unsigned " << LocCostName << " = ";
+    if (Group.size() == 1)
+      OS << "1;\n";    // Add inst cost if at individual rec
+    else
+      OS << "0;\n";
+
+    // Loop over all of the operands, adding in their costs...
+    TreePatternNode *N = Group[0].second;
+    const std::vector<TreePatternNode*> &Children = N->getChildren();
+
+    // If necessary, emit conditionals to check for the appropriate tree
+    // structure here...
+    for (unsigned i = 0, e = Children.size(); i != e; ++i) {
+      TreePatternNode *C = Children[i];
+      if (C->isLeaf()) {
+        // We already calculated the cost for this leaf, add it in now...
+        OS << Indent << "  " << LocCostName << " += "
+           << VarPrefix << "_Op" << utostr(i) << "_"
+           << C->getValueRecord()->getName() << "_Cost;\n";
+      } else {
+        // If it's not a leaf, we have to check to make sure that the current
+        // node has the appropriate structure, then recurse into it...
+        OS << Indent << "  if (" << VarPrefix << "_Op" << i
+           << "->getNodeType() == ISD::" << getNodeName(C->getOperator())
+           << ") {\n";
+        std::vector<std::pair<Pattern*, TreePatternNode*> > SubPatterns;
+        for (unsigned n = 0, e = Group.size(); n != e; ++n)
+          SubPatterns.push_back(std::make_pair(Group[n].first,
+                                               Group[n].second->getChild(i)));
+        EmitMatchCosters(OS, SubPatterns, VarPrefix+"_Op"+utostr(i),
+                         IndentAmt + 4);
+        OS << Indent << "  }\n";
+      }
+    }
+
+    // If the cost for this match is less than the minimum computed cost so far,
+    // update the minimum cost and selected pattern.
+    OS << Indent << "  if (" << LocCostName << " < " << LocCostName << "Min) { "
+       << LocCostName << "Min = " << LocCostName << "; " << VarPrefix
+       << "_PatternMin = " << VarPrefix << "_Pattern; }\n";
+    
+    OS << Indent << "}\n";
+  }
+#endif
+
+  for (unsigned i = 0, e = Patterns.size(); i != e; ++i) {
+    Pattern *P = Patterns[i].first;
+    TreePatternNode *PTree = P->getTree();
+    unsigned PatternCost = 1;
+
+    // Check to see if there are any non-leaf elements in the pattern.  If so,
+    // we need to emit a predicate for this match.
+    bool AnyNonLeaf = false;
+    for (unsigned c = 0, e = PTree->getNumChildren(); c != e; ++c)
+      if (!PTree->getChild(c)->isLeaf()) {
+        AnyNonLeaf = true;
+        break;
+      }
+
+    if (!AnyNonLeaf) {   // No predicate necessary, just output a scope...
+      OS << "  {// " << *P << "\n";
+    } else {
+      // We need to emit a predicate to make sure the tree pattern matches, do
+      // so now...
+      OS << "  if (1";
+      for (unsigned c = 0, e = PTree->getNumChildren(); c != e; ++c)
+        if (!PTree->getChild(c)->isLeaf())
+          EmitPatternPredicates(PTree->getChild(c),
+                                VarPrefix + "_Op" + utostr(c), OS);
+
+      OS << ") {\n    // " << *P << "\n";
+    }
+
+    OS << "    unsigned PatCost = " << PatternCost;
+
+    for (unsigned c = 0, e = PTree->getNumChildren(); c != e; ++c)
+      if (PTree->getChild(c)->isLeaf()) {
+        OS << " + " << VarPrefix << "_Op" << c << "_"
+           << PTree->getChild(c)->getValueRecord()->getName() << "_Cost";
+      } else {
+        EmitPatternCosts(PTree->getChild(c), VarPrefix + "_Op" + utostr(c), OS);
+      }
+    OS << ";\n";
+    OS << "    if (PatCost < MinCost) { MinCost = PatCost; Pattern = "
+       << P->getRecord()->getName() << "_Pattern; }\n"
+       << "  }\n";
+  }
+}
+
+static void ReduceAllOperands(TreePatternNode *N, const std::string &Name,
+             std::vector<std::pair<TreePatternNode*, std::string> > &Operands,
+                              std::ostream &OS) {
+  if (N->isLeaf()) {
+    // If this is a leaf, register or nonterminal reference...
+    std::string SlotName = Pattern::getSlotName(N->getValueRecord());
+    OS << "    ReducedValue_" << SlotName << " *" << Name << "Val = Reduce_"
+       << SlotName << "(" << Name << ", MBB);\n";
+    Operands.push_back(std::make_pair(N, Name+"Val"));
+  } else if (N->getNumChildren() == 0) {
+    // This is a reference to a leaf tree node, like an immediate or frame
+    // index.
+    if (N->getType() != MVT::isVoid) {
+      std::string SlotName =
+        getNodeName(N->getOperator()) + "_" + getName(N->getType());
+      OS << "    ReducedValue_" << SlotName << " *" << Name << "Val = "
+         << Name << "->getValue<ReducedValue_" << SlotName << ">(ISD::"
+         << SlotName << "_Slot);\n";
+      Operands.push_back(std::make_pair(N, Name+"Val"));
+    }
+  } else {
+    // Otherwise this is an interior node...
+    for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i) {
+      std::string ChildName = Name + "_Op" + utostr(i);
+      OS << "    SelectionDAGNode *" << ChildName << " = " << Name
+         << "->getUse(" << i << ");\n";
+      ReduceAllOperands(N->getChild(i), ChildName, Operands, OS);
+    }
+  }
+}
+
+/// PrintExpanderOperand - Print out Arg as part of the instruction emission
+/// process for the expander pattern P.  This argument may be referencing some
+/// values defined in P, or may just be physical register references or
+/// something like that.  If PrintArg is true, we are printing out arguments to
+/// the BuildMI call.  If it is false, we are printing the result register
+/// name.
+void InstrSelectorEmitter::PrintExpanderOperand(Init *Arg,
+                                                const std::string &NameVar,
+                                                TreePatternNode *ArgDeclNode,
+                                                Pattern *P, bool PrintArg,
+                                                std::ostream &OS) {
+  if (DefInit *DI = dynamic_cast<DefInit*>(Arg)) {
+    Record *Arg = DI->getDef();
+    if (!ArgDeclNode->isLeaf() && ArgDeclNode->getNumChildren() != 0)
+      P->error("Expected leaf node as argument!");
+    Record *ArgDecl = ArgDeclNode->isLeaf() ? ArgDeclNode->getValueRecord() :
+                      ArgDeclNode->getOperator();
+    if (Arg->isSubClassOf("Register")) {
+      // This is a physical register reference... make sure that the instruction
+      // requested a register!
+      if (!ArgDecl->isSubClassOf("RegisterClass"))
+        P->error("Argument mismatch for instruction pattern!");
+
+      // FIXME: This should check to see if the register is in the specified
+      // register class!
+      if (PrintArg) OS << ".addReg(";
+      OS << getQualifiedName(Arg);
+      if (PrintArg) OS << ")";
+      return;
+    } else if (Arg->isSubClassOf("RegisterClass")) {
+      // If this is a symbolic register class reference, we must be using a
+      // named value.
+      if (NameVar.empty()) P->error("Did not specify WHICH register to pass!");
+      if (Arg != ArgDecl) P->error("Instruction pattern mismatch!");
+
+      if (PrintArg) OS << ".addReg(";
+      OS << NameVar;
+      if (PrintArg) OS << ")";
+      return;
+    } else if (Arg->getName() == "frameidx") {
+      if (!PrintArg) P->error("Cannot define a new frameidx value!");
+      OS << ".addFrameIndex(" << NameVar << ")";
+      return;
+    } else if (Arg->getName() == "basicblock") {
+      if (!PrintArg) P->error("Cannot define a new basicblock value!");
+      OS << ".addMBB(" << NameVar << ")";
+      return;
+    }
+    P->error("Unknown operand type '" + Arg->getName() + "' to expander!");
+  } else if (IntInit *II = dynamic_cast<IntInit*>(Arg)) {
+    if (!NameVar.empty())
+      P->error("Illegal to specify a name for a constant initializer arg!");
+
+    // Hack this check to allow R32 values with 0 as the initializer for memory
+    // references... FIXME!
+    if (ArgDeclNode->isLeaf() && II->getValue() == 0 &&
+        ArgDeclNode->getValueRecord()->getName() == "R32") {
+      OS << ".addReg(0)";
+    } else {
+      if (ArgDeclNode->isLeaf() || ArgDeclNode->getOperator()->getName()!="imm")
+        P->error("Illegal immediate int value '" + itostr(II->getValue()) +
+                 "' operand!");
+      OS << ".addZImm(" << II->getValue() << ")";
+    }
+    return;
+  }
+  P->error("Unknown operand type to expander!");
+}
+
+static std::string getArgName(Pattern *P, const std::string &ArgName, 
+       const std::vector<std::pair<TreePatternNode*, std::string> > &Operands) {
+  assert(P->getNumArgs() == Operands.size() &&"Argument computation mismatch!");
+  if (ArgName.empty()) return "";
+
+  for (unsigned i = 0, e = P->getNumArgs(); i != e; ++i)
+    if (P->getArgName(i) == ArgName)
+      return Operands[i].second + "->Val";
+
+  if (ArgName == P->getResultName())
+    return "NewReg";
+  P->error("Pattern does not define a value named $" + ArgName + "!");
+  return "";
+}
+
+
+void InstrSelectorEmitter::run(std::ostream &OS) {
+  // Type-check all of the node types to ensure we "understand" them.
+  ReadNodeTypes();
+  
+  // Read in all of the nonterminals, instructions, and expanders...
+  ReadNonterminals();
+  ReadInstructionPatterns();
+  ReadExpanderPatterns();
+
+  // Instantiate any unresolved nonterminals with information from the context
+  // that they are used in.
+  InstantiateNonterminals();
+
+  // Clear InstantiatedNTs, we don't need it anymore...
+  InstantiatedNTs.clear();
+
+  DEBUG(std::cerr << "Patterns acquired:\n");
+  for (std::map<Record*, Pattern*>::iterator I = Patterns.begin(),
+         E = Patterns.end(); I != E; ++I)
+    if (I->second->isResolved())
+      DEBUG(std::cerr << "  " << *I->second << "\n");
+
+  CalculateComputableValues();
+  
+  EmitSourceFileHeader("Instruction Selector for the " + Target.getName() +
+                       " target", OS);
+  OS << "#include \"llvm/CodeGen/MachineInstrBuilder.h\"\n";
+
+  // Output the slot number enums...
+  OS << "\nenum { // Slot numbers...\n"
+     << "  LastBuiltinSlot = ISD::NumBuiltinSlots-1, // Start numbering here\n";
+  for (PatternOrganizer::iterator I = ComputableValues.begin(),
+         E = ComputableValues.end(); I != E; ++I)
+    OS << "  " << I->first << "_Slot,\n";
+  OS << "  NumSlots\n};\n\n// Reduction value typedefs...\n";
+
+  // Output the reduction value typedefs...
+  for (PatternOrganizer::iterator I = ComputableValues.begin(),
+         E = ComputableValues.end(); I != E; ++I) {
+
+    OS << "typedef ReducedValue<unsigned, " << I->first
+       << "_Slot> ReducedValue_" << I->first << ";\n";
+  }
+
+  // Output the pattern enums...
+  OS << "\n\n"
+     << "enum { // Patterns...\n"
+     << "  NotComputed = 0,\n"
+     << "  NoMatchPattern, \n";
+  for (PatternOrganizer::iterator I = ComputableValues.begin(),
+         E = ComputableValues.end(); I != E; ++I) {
+    OS << "  // " << I->first << " patterns...\n";
+    for (PatternOrganizer::NodesForSlot::iterator J = I->second.begin(),
+           E = I->second.end(); J != E; ++J)
+      for (unsigned i = 0, e = J->second.size(); i != e; ++i)
+        OS << "  " << J->second[i]->getRecord()->getName() << "_Pattern,\n";
+  }
+  OS << "};\n\n";
+
+  //===--------------------------------------------------------------------===//
+  // Emit the class definition...
+  //
+  OS << "namespace {\n"
+     << "  class " << Target.getName() << "ISel {\n"
+     << "    SelectionDAG &DAG;\n"
+     << "  public:\n"
+     << "    X86ISel(SelectionDAG &D) : DAG(D) {}\n"
+     << "    void generateCode();\n"
+     << "  private:\n"
+     << "    unsigned makeAnotherReg(const TargetRegisterClass *RC) {\n"
+     << "      return DAG.getMachineFunction().getSSARegMap()->createVirt"
+                                       "ualRegister(RC);\n"
+     << "    }\n\n"
+     << "    // DAG matching methods for classes... all of these methods"
+                                       " return the cost\n"
+     << "    // of producing a value of the specified class and type, which"
+                                       " also gets\n"
+     << "    // added to the DAG node.\n";
+
+  // Output all of the matching prototypes for slots...
+  for (PatternOrganizer::iterator I = ComputableValues.begin(),
+         E = ComputableValues.end(); I != E; ++I)
+    OS << "    unsigned Match_" << I->first << "(SelectionDAGNode *N);\n";
+  OS << "\n    // DAG matching methods for DAG nodes...\n";
+
+  // Output all of the matching prototypes for slot/node pairs
+  for (PatternOrganizer::iterator I = ComputableValues.begin(),
+         E = ComputableValues.end(); I != E; ++I)
+    for (PatternOrganizer::NodesForSlot::iterator J = I->second.begin(),
+           E = I->second.end(); J != E; ++J)
+      OS << "    unsigned Match_" << I->first << "_" << getNodeName(J->first)
+         << "(SelectionDAGNode *N);\n";
+
+  // Output all of the dag reduction methods prototypes...
+  OS << "\n    // DAG reduction methods...\n";
+  for (PatternOrganizer::iterator I = ComputableValues.begin(),
+         E = ComputableValues.end(); I != E; ++I)
+    OS << "    ReducedValue_" << I->first << " *Reduce_" << I->first
+       << "(SelectionDAGNode *N,\n" << std::string(27+2*I->first.size(), ' ')
+       << "MachineBasicBlock *MBB);\n";
+  OS << "  };\n}\n\n";
+
+  // Emit the generateCode entry-point...
+  OS << "void X86ISel::generateCode() {\n"
+     << "  SelectionDAGNode *Root = DAG.getRoot();\n"
+     << "  assert(Root->getValueType() == MVT::isVoid && "
+                                       "\"Root of DAG produces value??\");\n\n"
+     << "  std::cerr << \"\\n\";\n"
+     << "  unsigned Cost = Match_Void_void(Root);\n"
+     << "  if (Cost >= ~0U >> 1) {\n"
+     << "    std::cerr << \"Match failed!\\n\";\n"
+     << "    Root->dump();\n"
+     << "    abort();\n"
+     << "  }\n\n"
+     << "  std::cerr << \"Total DAG Cost: \" << Cost << \"\\n\\n\";\n\n"
+     << "  Reduce_Void_void(Root, 0);\n"
+     << "}\n\n"
+     << "//===" << std::string(70, '-') << "===//\n"
+     << "//  Matching methods...\n"
+     << "//\n\n";
+
+  //===--------------------------------------------------------------------===//
+  // Emit all of the matcher methods...
+  //
+  for (PatternOrganizer::iterator I = ComputableValues.begin(),
+         E = ComputableValues.end(); I != E; ++I) {
+    const std::string &SlotName = I->first;
+    OS << "unsigned " << Target.getName() << "ISel::Match_" << SlotName
+       << "(SelectionDAGNode *N) {\n"
+       << "  assert(N->getValueType() == MVT::"
+       << getEnumName((*I->second.begin()).second[0]->getTree()->getType())
+       << ");\n" << "  // If we already have a cost available for " << SlotName
+       << " use it!\n"
+       << "  if (N->getPatternFor(" << SlotName << "_Slot))\n"
+       << "    return N->getCostFor(" << SlotName << "_Slot);\n\n"
+       << "  unsigned Cost;\n"
+       << "  switch (N->getNodeType()) {\n"
+       << "  default: Cost = ~0U >> 1;   // Match failed\n"
+       << "           N->setPatternCostFor(" << SlotName << "_Slot, NoMatchPattern, Cost, NumSlots);\n"
+       << "           break;\n";
+
+    for (PatternOrganizer::NodesForSlot::iterator J = I->second.begin(),
+           E = I->second.end(); J != E; ++J)
+      if (!J->first->isSubClassOf("Nonterminal"))
+        OS << "  case ISD::" << getNodeName(J->first) << ":\tCost = Match_"
+           << SlotName << "_" << getNodeName(J->first) << "(N); break;\n";
+    OS << "  }\n";  // End of the switch statement
+
+    // Emit any patterns which have a nonterminal leaf as the RHS.  These may
+    // match multiple root nodes, so they cannot be handled with the switch...
+    for (PatternOrganizer::NodesForSlot::iterator J = I->second.begin(),
+           E = I->second.end(); J != E; ++J)
+      if (J->first->isSubClassOf("Nonterminal")) {
+        OS << "  unsigned " << J->first->getName() << "_Cost = Match_"
+           << getNodeName(J->first) << "(N);\n"
+           << "  if (" << getNodeName(J->first) << "_Cost < Cost) Cost = "
+           << getNodeName(J->first) << "_Cost;\n";
+      }
+
+    OS << "  return Cost;\n}\n\n";
+
+    for (PatternOrganizer::NodesForSlot::iterator J = I->second.begin(),
+           E = I->second.end(); J != E; ++J) {
+      Record *Operator = J->first;
+      bool isNonterm = Operator->isSubClassOf("Nonterminal");
+      if (!isNonterm) {
+        OS << "unsigned " << Target.getName() << "ISel::Match_";
+        if (!isNonterm) OS << SlotName << "_";
+        OS << getNodeName(Operator) << "(SelectionDAGNode *N) {\n"
+           << "  unsigned Pattern = NoMatchPattern;\n"
+           << "  unsigned MinCost = ~0U >> 1;\n";
+        
+        std::vector<std::pair<Pattern*, TreePatternNode*> > Patterns;
+        for (unsigned i = 0, e = J->second.size(); i != e; ++i)
+          Patterns.push_back(std::make_pair(J->second[i],
+                                            J->second[i]->getTree()));
+        EmitMatchCosters(OS, Patterns, "N", 2);
+        
+        OS << "\n  N->setPatternCostFor(" << SlotName
+           << "_Slot, Pattern, MinCost, NumSlots);\n"
+           << "  return MinCost;\n"
+           << "}\n";
+      }
+    }
+  }
+
+  //===--------------------------------------------------------------------===//
+  // Emit all of the reducer methods...
+  //
+  OS << "\n\n//===" << std::string(70, '-') << "===//\n"
+     << "// Reducer methods...\n"
+     << "//\n";
+
+  for (PatternOrganizer::iterator I = ComputableValues.begin(),
+         E = ComputableValues.end(); I != E; ++I) {
+    const std::string &SlotName = I->first;
+    OS << "ReducedValue_" << SlotName << " *" << Target.getName()
+       << "ISel::Reduce_" << SlotName
+       << "(SelectionDAGNode *N, MachineBasicBlock *MBB) {\n"
+       << "  ReducedValue_" << SlotName << " *Val = N->hasValue<ReducedValue_"
+       << SlotName << ">(" << SlotName << "_Slot);\n"
+       << "  if (Val) return Val;\n"
+       << "  if (N->getBB()) MBB = N->getBB();\n\n"
+       << "  switch (N->getPatternFor(" << SlotName << "_Slot)) {\n";
+
+    // Loop over all of the patterns that can produce a value for this slot...
+    PatternOrganizer::NodesForSlot &NodesForSlot = I->second;
+    for (PatternOrganizer::NodesForSlot::iterator J = NodesForSlot.begin(),
+           E = NodesForSlot.end(); J != E; ++J)
+      for (unsigned i = 0, e = J->second.size(); i != e; ++i) {
+        Pattern *P = J->second[i];
+        OS << "  case " << P->getRecord()->getName() << "_Pattern: {\n"
+           << "    // " << *P << "\n";
+        // Loop over the operands, reducing them...
+        std::vector<std::pair<TreePatternNode*, std::string> > Operands;
+        ReduceAllOperands(P->getTree(), "N", Operands, OS);
+        
+        // Now that we have reduced all of our operands, and have the values
+        // that reduction produces, perform the reduction action for this
+        // pattern.
+        std::string Result;
+
+        // If the pattern produces a register result, generate a new register
+        // now.
+        if (Record *R = P->getResult()) {
+          assert(R->isSubClassOf("RegisterClass") &&
+                 "Only handle register class results so far!");
+          OS << "    unsigned NewReg = makeAnotherReg(" << Target.getName()
+             << "::" << R->getName() << "RegisterClass);\n";
+          Result = "NewReg";
+          DEBUG(OS << "    std::cerr << \"%reg\" << NewReg << \" =\t\";\n");
+        } else {
+          DEBUG(OS << "    std::cerr << \"\t\t\";\n");
+          Result = "0";
+        }
+
+        // Print out the pattern that matched...
+        DEBUG(OS << "    std::cerr << \"  " << P->getRecord()->getName() <<'"');
+        DEBUG(for (unsigned i = 0, e = Operands.size(); i != e; ++i)
+                if (Operands[i].first->isLeaf()) {
+                  Record *RV = Operands[i].first->getValueRecord();
+                  assert(RV->isSubClassOf("RegisterClass") &&
+                         "Only handles registers here so far!");
+                  OS << " << \" %reg\" << " << Operands[i].second
+                     << "->Val";
+                } else {
+                  OS << " << ' ' << " << Operands[i].second
+                     << "->Val";
+                });
+        DEBUG(OS << " << \"\\n\";\n");
+        
+        // Generate the reduction code appropriate to the particular type of
+        // pattern that this is...
+        switch (P->getPatternType()) {
+        case Pattern::Instruction:
+          // Instruction patterns just emit a single MachineInstr, using BuildMI
+          OS << "    BuildMI(MBB, " << Target.getName() << "::"
+             << P->getRecord()->getName() << ", " << Operands.size();
+          if (P->getResult()) OS << ", NewReg";
+          OS << ")";
+
+          for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
+            TreePatternNode *Op = Operands[i].first;
+            if (Op->isLeaf()) {
+              Record *RV = Op->getValueRecord();
+              assert(RV->isSubClassOf("RegisterClass") &&
+                     "Only handles registers here so far!");
+              OS << ".addReg(" << Operands[i].second << "->Val)";
+            } else if (Op->getOperator()->getName() == "imm") {
+              OS << ".addZImm(" << Operands[i].second << "->Val)";
+            } else if (Op->getOperator()->getName() == "basicblock") {
+              OS << ".addMBB(" << Operands[i].second << "->Val)";
+            } else {
+              assert(0 && "Unknown value type!");
+            }
+          }
+          OS << ";\n";
+          break;
+        case Pattern::Expander: {
+          // Expander patterns emit one machine instr for each instruction in
+          // the list of instructions expanded to.
+          ListInit *Insts = P->getRecord()->getValueAsListInit("Result");
+          for (unsigned IN = 0, e = Insts->getSize(); IN != e; ++IN) {
+            DagInit *DIInst = dynamic_cast<DagInit*>(Insts->getElement(IN));
+            if (!DIInst) P->error("Result list must contain instructions!");
+            Record *InstRec  = DIInst->getNodeType();
+            Pattern *InstPat = getPattern(InstRec);
+            if (!InstPat || InstPat->getPatternType() != Pattern::Instruction)
+              P->error("Instruction list must contain Instruction patterns!");
+            
+            bool hasResult = InstPat->getResult() != 0;
+            if (InstPat->getNumArgs() != DIInst->getNumArgs()-hasResult) {
+              P->error("Incorrect number of arguments specified for inst '" +
+                       InstPat->getRecord()->getName() + "' in result list!");
+            }
+
+            // Start emission of the instruction...
+            OS << "    BuildMI(MBB, " << Target.getName() << "::"
+               << InstRec->getName() << ", "
+               << DIInst->getNumArgs()-hasResult;
+            // Emit register result if necessary..
+            if (hasResult) {
+              std::string ArgNameVal =
+                getArgName(P, DIInst->getArgName(0), Operands);
+              PrintExpanderOperand(DIInst->getArg(0), ArgNameVal,
+                                   InstPat->getResultNode(), P, false,
+                                   OS << ", ");
+            }
+            OS << ")";
+
+            for (unsigned i = hasResult, e = DIInst->getNumArgs(); i != e; ++i){
+              std::string ArgNameVal =
+                getArgName(P, DIInst->getArgName(i), Operands);
+
+              PrintExpanderOperand(DIInst->getArg(i), ArgNameVal,
+                                   InstPat->getArg(i-hasResult), P, true, OS);
+            }
+
+            OS << ";\n";
+          }
+          break;
+        }
+        default:
+          assert(0 && "Reduction of this type of pattern not implemented!");
+        }
+
+        OS << "    Val = new ReducedValue_" << SlotName << "(" << Result<<");\n"
+           << "    break;\n"
+           << "  }\n";
+      }
+    
+    
+    OS << "  default: assert(0 && \"Unknown " << SlotName << " pattern!\");\n"
+       << "  }\n\n  N->addValue(Val);  // Do not ever recalculate this\n"
+       << "  return Val;\n}\n\n";
+  }
+}
+