llvm/lib/Target/SparcV9/ModuloScheduling/ModuloScheduling.cpp

//===-- ModuloScheduling.cpp - ModuloScheduling  ----------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This ModuloScheduling pass is based on the Swing Modulo Scheduling
//  algorithm.
//
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "ModuloSched"

#include "ModuloScheduling.h"
#include "llvm/Constants.h"
#include "llvm/Instructions.h"
#include "llvm/Function.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/CFG.h"
#include "llvm/Target/TargetSchedInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/ADT/SCCIterator.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Timer.h"
#include <cmath>
#include <algorithm>
#include <fstream>
#include <sstream>
#include <utility>
#include <vector>
#include "../MachineCodeForInstruction.h"
#include "../SparcV9TmpInstr.h"
#include "../SparcV9Internals.h"
#include "../SparcV9RegisterInfo.h"
using namespace llvm;

/// Create ModuloSchedulingPass
///
FunctionPass *llvm::createModuloSchedulingPass(TargetMachine & targ) {
  DEBUG(std::cerr << "Created ModuloSchedulingPass\n");
  return new ModuloSchedulingPass(targ);
}


//Graph Traits for printing out the dependence graph
template<typename GraphType>
static void WriteGraphToFile(std::ostream &O, const std::string &GraphName,
                             const GraphType &GT) {
  std::string Filename = GraphName + ".dot";
  O << "Writing '" << Filename << "'...";
  std::ofstream F(Filename.c_str());

  if (F.good())
    WriteGraph(F, GT);
  else
    O << "  error opening file for writing!";
  O << "\n";
};


#if 1
#define TIME_REGION(VARNAME, DESC) \
   NamedRegionTimer VARNAME(DESC)
#else
#define TIME_REGION(VARNAME, DESC)
#endif


//Graph Traits for printing out the dependence graph
namespace llvm {

  //Loop statistics
  Statistic<> ValidLoops("modulosched-validLoops", "Number of candidate loops modulo-scheduled");
  Statistic<> JumboBB("modulosched-jumboBB", "Basic Blocks with more then 100 instructions");
  Statistic<> LoopsWithCalls("modulosched-loopCalls", "Loops with calls");
  Statistic<> LoopsWithCondMov("modulosched-loopCondMov", "Loops with conditional moves");
  Statistic<> InvalidLoops("modulosched-invalidLoops", "Loops with unknown trip counts or loop invariant trip counts");
  Statistic<> SingleBBLoops("modulosched-singeBBLoops", "Number of single basic block loops");

  //Scheduling Statistics
  Statistic<> MSLoops("modulosched-schedLoops", "Number of loops successfully modulo-scheduled");
  Statistic<> NoSched("modulosched-noSched", "No schedule");
  Statistic<> SameStage("modulosched-sameStage", "Max stage is 0");
  Statistic<> ResourceConstraint("modulosched-resourceConstraint", "Loops constrained by resources");
  Statistic<> RecurrenceConstraint("modulosched-recurrenceConstraint", "Loops constrained by recurrences");
   Statistic<> FinalIISum("modulosched-finalIISum", "Sum of all final II");
  Statistic<> IISum("modulosched-IISum", "Sum of all theoretical II");

  template<>
  struct DOTGraphTraits<MSchedGraph*> : public DefaultDOTGraphTraits {
    static std::string getGraphName(MSchedGraph *F) {
      return "Dependence Graph";
    }

    static std::string getNodeLabel(MSchedGraphNode *Node, MSchedGraph *Graph) {
      if (Node->getInst()) {
        std::stringstream ss;
        ss << *(Node->getInst());
        return ss.str(); //((MachineInstr*)Node->getInst());
      }
      else
        return "No Inst";
    }
    static std::string getEdgeSourceLabel(MSchedGraphNode *Node,
                                          MSchedGraphNode::succ_iterator I) {
      //Label each edge with the type of dependence
      std::string edgelabel = "";
      switch (I.getEdge().getDepOrderType()) {

      case MSchedGraphEdge::TrueDep:
        edgelabel = "True";
        break;

      case MSchedGraphEdge::AntiDep:
        edgelabel =  "Anti";
        break;

      case MSchedGraphEdge::OutputDep:
        edgelabel = "Output";
        break;

      default:
        edgelabel = "Unknown";
        break;
      }

      //FIXME
      int iteDiff = I.getEdge().getIteDiff();
      std::string intStr = "(IteDiff: ";
      intStr += itostr(iteDiff);

      intStr += ")";
      edgelabel += intStr;

      return edgelabel;
    }
  };
}


#include <unistd.h>

/// ModuloScheduling::runOnFunction - main transformation entry point
/// The Swing Modulo Schedule algorithm has three basic steps:
/// 1) Computation and Analysis of the dependence graph
/// 2) Ordering of the nodes
/// 3) Scheduling
///
bool ModuloSchedulingPass::runOnFunction(Function &F) {
  alarm(100);

  bool Changed = false;
  int numMS = 0;

  DEBUG(std::cerr << "Creating ModuloSchedGraph for each valid BasicBlock in " + F.getName() + "\n");

  //Get MachineFunction
  MachineFunction &MF = MachineFunction::get(&F);

  DependenceAnalyzer &DA = getAnalysis<DependenceAnalyzer>();


  //Worklist
  std::vector<MachineBasicBlock*> Worklist;

  //Iterate over BasicBlocks and put them into our worklist if they are valid
  for (MachineFunction::iterator BI = MF.begin(); BI != MF.end(); ++BI)
    if(MachineBBisValid(BI)) {
      if(BI->size() < 100) {
        Worklist.push_back(&*BI);
        ++ValidLoops;
      }
      else
        ++JumboBB;

    }

  defaultInst = 0;

  DEBUG(if(Worklist.size() == 0) std::cerr << "No single basic block loops in function to ModuloSchedule\n");

  //Iterate over the worklist and perform scheduling
  for(std::vector<MachineBasicBlock*>::iterator BI = Worklist.begin(),
        BE = Worklist.end(); BI != BE; ++BI) {

    //Print out BB for debugging
    DEBUG(std::cerr << "BB Size: " << (*BI)->size() << "\n");
    DEBUG(std::cerr << "ModuloScheduling BB: \n"; (*BI)->print(std::cerr));

    //Print out LLVM BB
    DEBUG(std::cerr << "ModuloScheduling LLVMBB: \n"; (*BI)->getBasicBlock()->print(std::cerr));

    //Catch the odd case where we only have TmpInstructions and no real Value*s
    if(!CreateDefMap(*BI)) {
      //Clear out our maps for the next basic block that is processed
      nodeToAttributesMap.clear();
      partialOrder.clear();
      recurrenceList.clear();
      FinalNodeOrder.clear();
      schedule.clear();
      defMap.clear();
      continue;
    }

    MSchedGraph *MSG = new MSchedGraph(*BI, target, indVarInstrs[*BI], DA, machineTollvm[*BI]);

    //Write Graph out to file
    DEBUG(WriteGraphToFile(std::cerr, F.getName(), MSG));
    DEBUG(MSG->print(std::cerr));

    //Calculate Resource II
    int ResMII = calculateResMII(*BI);

    //Calculate Recurrence II
    int RecMII = calculateRecMII(MSG, ResMII);

    DEBUG(std::cerr << "Number of reccurrences found: " << recurrenceList.size() << "\n");

    //Our starting initiation interval is the maximum of RecMII and ResMII
    if(RecMII < ResMII)
      ++RecurrenceConstraint;
    else
      ++ResourceConstraint;

    II = std::max(RecMII, ResMII);
    int mII = II;

    //Print out II, RecMII, and ResMII
    DEBUG(std::cerr << "II starts out as " << II << " ( RecMII=" << RecMII << " and ResMII=" << ResMII << ")\n");

    //Dump node properties if in debug mode
    DEBUG(for(std::map<MSchedGraphNode*, MSNodeAttributes>::iterator I =  nodeToAttributesMap.begin(),
                E = nodeToAttributesMap.end(); I !=E; ++I) {
            std::cerr << "Node: " << *(I->first) << " ASAP: " << I->second.ASAP << " ALAP: "
                      << I->second.ALAP << " MOB: " << I->second.MOB << " Depth: " << I->second.depth
                      << " Height: " << I->second.height << "\n";
          });

    //Calculate Node Properties
    calculateNodeAttributes(MSG, ResMII);

    //Dump node properties if in debug mode
    DEBUG(for(std::map<MSchedGraphNode*, MSNodeAttributes>::iterator I =  nodeToAttributesMap.begin(),
                E = nodeToAttributesMap.end(); I !=E; ++I) {
            std::cerr << "Node: " << *(I->first) << " ASAP: " << I->second.ASAP << " ALAP: "
                      << I->second.ALAP << " MOB: " << I->second.MOB << " Depth: " << I->second.depth
                      << " Height: " << I->second.height << "\n";
          });

    //Put nodes in order to schedule them
    computePartialOrder();

    //Dump out partial order
    DEBUG(for(std::vector<std::set<MSchedGraphNode*> >::iterator I = partialOrder.begin(),
                E = partialOrder.end(); I !=E; ++I) {
            std::cerr << "Start set in PO\n";
            for(std::set<MSchedGraphNode*>::iterator J = I->begin(), JE = I->end(); J != JE; ++J)
              std::cerr << "PO:" << **J << "\n";
          });

    //Place nodes in final order
    orderNodes();

    //Dump out order of nodes
    DEBUG(for(std::vector<MSchedGraphNode*>::iterator I = FinalNodeOrder.begin(), E = FinalNodeOrder.end(); I != E; ++I) {
            std::cerr << "FO:" << **I << "\n";
          });

    //Finally schedule nodes
    bool haveSched = computeSchedule(*BI, MSG);

    //Print out final schedule
    DEBUG(schedule.print(std::cerr));

    //Final scheduling step is to reconstruct the loop only if we actual have
    //stage > 0
    if(haveSched) {
      reconstructLoop(*BI);
      ++MSLoops;
      Changed = true;
      FinalIISum += II;
      IISum += mII;

      if(schedule.getMaxStage() == 0)
        ++SameStage;
    }
    else {
      ++NoSched;
    }

    //Clear out our maps for the next basic block that is processed
    nodeToAttributesMap.clear();
    partialOrder.clear();
    recurrenceList.clear();
    FinalNodeOrder.clear();
    schedule.clear();
    defMap.clear();
    //Clean up. Nuke old MachineBB and llvmBB
    //BasicBlock *llvmBB = (BasicBlock*) (*BI)->getBasicBlock();
    //Function *parent = (Function*) llvmBB->getParent();
    //Should't std::find work??
    //parent->getBasicBlockList().erase(std::find(parent->getBasicBlockList().begin(), parent->getBasicBlockList().end(), *llvmBB));
    //parent->getBasicBlockList().erase(llvmBB);

    //delete(llvmBB);
    //delete(*BI);
  }

  alarm(0);
  return Changed;
}

bool ModuloSchedulingPass::CreateDefMap(MachineBasicBlock *BI) {
  defaultInst = 0;

  for(MachineBasicBlock::iterator I = BI->begin(), E = BI->end(); I != E; ++I) {
    for(unsigned opNum = 0; opNum < I->getNumOperands(); ++opNum) {
      const MachineOperand &mOp = I->getOperand(opNum);
      if(mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isDef()) {
        //assert if this is the second def we have seen
        //DEBUG(std::cerr << "Putting " << *(mOp.getVRegValue()) << " into map\n");
        //assert(!defMap.count(mOp.getVRegValue()) && "Def already in the map");
        if(defMap.count(mOp.getVRegValue()))
          return false;

        defMap[mOp.getVRegValue()] = &*I;
      }

      //See if we can use this Value* as our defaultInst
      if(!defaultInst && mOp.getType() == MachineOperand::MO_VirtualRegister) {
        Value *V = mOp.getVRegValue();
        if(!isa<TmpInstruction>(V) && !isa<Argument>(V) && !isa<Constant>(V) && !isa<PHINode>(V))
          defaultInst = (Instruction*) V;
      }
    }
  }

  if(!defaultInst)
    return false;

  return true;

}
/// This function checks if a Machine Basic Block is valid for modulo
/// scheduling. This means that it has no control flow (if/else or
/// calls) in the block.  Currently ModuloScheduling only works on
/// single basic block loops.
bool ModuloSchedulingPass::MachineBBisValid(const MachineBasicBlock *BI) {

  bool isLoop = false;

  //Check first if its a valid loop
  for(succ_const_iterator I = succ_begin(BI->getBasicBlock()),
        E = succ_end(BI->getBasicBlock()); I != E; ++I) {
    if (*I == BI->getBasicBlock())    // has single block loop
      isLoop = true;
  }

  if(!isLoop)
    return false;

  //Check that we have a conditional branch (avoiding MS infinite loops)
  if(BranchInst *b = dyn_cast<BranchInst>(((BasicBlock*) BI->getBasicBlock())->getTerminator()))
    if(b->isUnconditional())
      return false;

  //Check size of our basic block.. make sure we have more then just the terminator in it
  if(BI->getBasicBlock()->size() == 1)
    return false;

  //Increase number of single basic block loops for stats
  ++SingleBBLoops;

  //Get Target machine instruction info
  const TargetInstrInfo *TMI = target.getInstrInfo();

  //Check each instruction and look for calls, keep map to get index later
  std::map<const MachineInstr*, unsigned> indexMap;

  unsigned count = 0;
  for(MachineBasicBlock::const_iterator I = BI->begin(), E = BI->end(); I != E; ++I) {
    //Get opcode to check instruction type
    MachineOpCode OC = I->getOpcode();

    //Look for calls
    if(TMI->isCall(OC)) {
      ++LoopsWithCalls;
      return false;
    }

    //Look for conditional move
    if(OC == V9::MOVRZr || OC == V9::MOVRZi || OC == V9::MOVRLEZr || OC == V9::MOVRLEZi
       || OC == V9::MOVRLZr || OC == V9::MOVRLZi || OC == V9::MOVRNZr || OC == V9::MOVRNZi
       || OC == V9::MOVRGZr || OC == V9::MOVRGZi || OC == V9::MOVRGEZr
       || OC == V9::MOVRGEZi || OC == V9::MOVLEr || OC == V9::MOVLEi || OC == V9::MOVLEUr
       || OC == V9::MOVLEUi || OC == V9::MOVFLEr || OC == V9::MOVFLEi
       || OC == V9::MOVNEr || OC == V9::MOVNEi || OC == V9::MOVNEGr || OC == V9::MOVNEGi
       || OC == V9::MOVFNEr || OC == V9::MOVFNEi || OC == V9::MOVGr || OC == V9::MOVGi) {
      ++LoopsWithCondMov;
      return false;
    }

    indexMap[I] = count;

    if(TMI->isNop(OC))
      continue;

    ++count;
  }

  //Apply a simple pattern match to make sure this loop can be modulo scheduled
  //This means only loops with a branch associated to the iteration count

  //Get the branch
  BranchInst *b = dyn_cast<BranchInst>(((BasicBlock*) BI->getBasicBlock())->getTerminator());

  //Get the condition for the branch (we already checked if it was conditional)
  Value *cond = b->getCondition();

  DEBUG(std::cerr << "Condition: " << *cond << "\n");

  //List of instructions associated with induction variable
  std::set<Instruction*> indVar;
  std::vector<Instruction*> stack;

  BasicBlock *BB = (BasicBlock*) BI->getBasicBlock();

  //Add branch
  indVar.insert(b);

  if(Instruction *I = dyn_cast<Instruction>(cond))
    if(I->getParent() == BB) {
      if (!assocIndVar(I, indVar, stack, BB)) {
        ++InvalidLoops;
        return false;
      }
    }
    else {
      ++InvalidLoops;
      return false;
    }
  else {
    ++InvalidLoops;
    return false;
  }
  //The indVar set must be >= 3 instructions for this loop to match (FIX ME!)
  if(indVar.size() < 3 )
    return false;

  //Dump out instructions associate with indvar for debug reasons
  DEBUG(for(std::set<Instruction*>::iterator N = indVar.begin(), NE = indVar.end(); N != NE; ++N) {
          std::cerr << **N << "\n";
        });

  //Create map of machine instr to llvm instr
  std::map<MachineInstr*, Instruction*> mllvm;
  for(BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
    MachineCodeForInstruction & tempMvec = MachineCodeForInstruction::get(I);
    for (unsigned j = 0; j < tempMvec.size(); j++) {
      mllvm[tempMvec[j]] = I;
    }
  }

  //Convert list of LLVM Instructions to list of Machine instructions
  std::map<const MachineInstr*, unsigned> mIndVar;
  for(std::set<Instruction*>::iterator N = indVar.begin(), NE = indVar.end(); N != NE; ++N) {

    //If we have a load, we can't handle this loop because there is no way to preserve dependences
    //between loads and stores
    if(isa<LoadInst>(*N))
      return false;

    MachineCodeForInstruction & tempMvec = MachineCodeForInstruction::get(*N);
    for (unsigned j = 0; j < tempMvec.size(); j++) {
      MachineOpCode OC = (tempMvec[j])->getOpcode();
      if(TMI->isNop(OC))
        continue;
      if(!indexMap.count(tempMvec[j]))
        continue;
      mIndVar[(MachineInstr*) tempMvec[j]] = indexMap[(MachineInstr*) tempMvec[j]];
      DEBUG(std::cerr << *(tempMvec[j]) << " at index " << indexMap[(MachineInstr*) tempMvec[j]] << "\n");
    }
  }

   //Must have some guts to the loop body (more then 1 instr, dont count nops in size)
  if(mIndVar.size() >= (BI->size()-3))
    return false;

  //Put into a map for future access
  indVarInstrs[BI] = mIndVar;
  machineTollvm[BI] = mllvm;
  return true;
}

bool ModuloSchedulingPass::assocIndVar(Instruction *I, std::set<Instruction*> &indVar,
                                       std::vector<Instruction*> &stack, BasicBlock *BB) {

  stack.push_back(I);

  //If this is a phi node, check if its the canonical indvar
  if(PHINode *PN = dyn_cast<PHINode>(I)) {
    if (Instruction *Inc =
        dyn_cast<Instruction>(PN->getIncomingValueForBlock(BB)))
      if (Inc->getOpcode() == Instruction::Add && Inc->getOperand(0) == PN)
        if (ConstantInt *CI = dyn_cast<ConstantInt>(Inc->getOperand(1)))
          if (CI->equalsInt(1)) {
            //We have found the indvar, so add the stack, and inc instruction to the set
            indVar.insert(stack.begin(), stack.end());
            indVar.insert(Inc);
            stack.pop_back();
            return true;
          }
    return false;
  }
  else {
    //Loop over each of the instructions operands, check if they are an instruction and in this BB
    for(unsigned i = 0; i < I->getNumOperands(); ++i) {
      if(Instruction *N =  dyn_cast<Instruction>(I->getOperand(i))) {
        if(N->getParent() == BB)
          if(!assocIndVar(N, indVar, stack, BB))
            return false;
      }
    }
  }

  stack.pop_back();
  return true;
}

//ResMII is calculated by determining the usage count for each resource
//and using the maximum.
//FIXME: In future there should be a way to get alternative resources
//for each instruction
int ModuloSchedulingPass::calculateResMII(const MachineBasicBlock *BI) {

  TIME_REGION(X, "calculateResMII");

  const TargetInstrInfo *mii = target.getInstrInfo();
  const TargetSchedInfo *msi = target.getSchedInfo();

  int ResMII = 0;

  //Map to keep track of usage count of each resource
  std::map<unsigned, unsigned> resourceUsageCount;

  for(MachineBasicBlock::const_iterator I = BI->begin(), E = BI->end(); I != E; ++I) {

    //Get resource usage for this instruction
    InstrRUsage rUsage = msi->getInstrRUsage(I->getOpcode());
    std::vector<std::vector<resourceId_t> > resources = rUsage.resourcesByCycle;

    //Loop over resources in each cycle and increments their usage count
    for(unsigned i=0; i < resources.size(); ++i)
      for(unsigned j=0; j < resources[i].size(); ++j) {
        if(!resourceUsageCount.count(resources[i][j])) {
          resourceUsageCount[resources[i][j]] = 1;
        }
        else {
          resourceUsageCount[resources[i][j]] =  resourceUsageCount[resources[i][j]] + 1;
        }
      }
  }

  //Find maximum usage count

  //Get max number of instructions that can be issued at once. (FIXME)
  int issueSlots = msi->maxNumIssueTotal;

  for(std::map<unsigned,unsigned>::iterator RB = resourceUsageCount.begin(), RE = resourceUsageCount.end(); RB != RE; ++RB) {

    //Get the total number of the resources in our cpu
    int resourceNum = CPUResource::getCPUResource(RB->first)->maxNumUsers;

    //Get total usage count for this resources
    unsigned usageCount = RB->second;

    //Divide the usage count by either the max number we can issue or the number of
    //resources (whichever is its upper bound)
    double finalUsageCount;
    DEBUG(std::cerr << "Resource Num: " << RB->first << " Usage: " << usageCount << " TotalNum: " << resourceNum << "\n");

    if( resourceNum <= issueSlots)
      finalUsageCount = ceil(1.0 * usageCount / resourceNum);
    else
      finalUsageCount = ceil(1.0 * usageCount / issueSlots);


    //Only keep track of the max
    ResMII = std::max( (int) finalUsageCount, ResMII);

  }

  return ResMII;

}

/// calculateRecMII - Calculates the value of the highest recurrence
/// By value we mean the total latency
int ModuloSchedulingPass::calculateRecMII(MSchedGraph *graph, int MII) {
  /*std::vector<MSchedGraphNode*> vNodes;
  //Loop over all nodes in the graph
  for(MSchedGraph::iterator I = graph->begin(), E = graph->end(); I != E; ++I) {
    findAllReccurrences(I->second, vNodes, MII);
    vNodes.clear();
  }*/

  TIME_REGION(X, "calculateRecMII");

  findAllCircuits(graph, MII);
  int RecMII = 0;

 for(std::set<std::pair<int, std::vector<MSchedGraphNode*> > >::iterator I = recurrenceList.begin(), E=recurrenceList.end(); I !=E; ++I) {
    RecMII = std::max(RecMII, I->first);
  }

  return MII;
}

/// calculateNodeAttributes - The following properties are calculated for
/// each node in the dependence graph: ASAP, ALAP, Depth, Height, and
/// MOB.
void ModuloSchedulingPass::calculateNodeAttributes(MSchedGraph *graph, int MII) {

  TIME_REGION(X, "calculateNodeAttributes");

  assert(nodeToAttributesMap.empty() && "Node attribute map was not cleared");

  //Loop over the nodes and add them to the map
  for(MSchedGraph::iterator I = graph->begin(), E = graph->end(); I != E; ++I) {

    DEBUG(std::cerr << "Inserting node into attribute map: " << *I->second << "\n");

    //Assert if its already in the map
    assert(nodeToAttributesMap.count(I->second) == 0 &&
           "Node attributes are already in the map");

    //Put into the map with default attribute values
    nodeToAttributesMap[I->second] = MSNodeAttributes();
  }

  //Create set to deal with reccurrences
  std::set<MSchedGraphNode*> visitedNodes;

  //Now Loop over map and calculate the node attributes
  for(std::map<MSchedGraphNode*, MSNodeAttributes>::iterator I = nodeToAttributesMap.begin(), E = nodeToAttributesMap.end(); I != E; ++I) {
    calculateASAP(I->first, MII, (MSchedGraphNode*) 0);
    visitedNodes.clear();
  }

  int maxASAP = findMaxASAP();
  //Calculate ALAP which depends on ASAP being totally calculated
  for(std::map<MSchedGraphNode*, MSNodeAttributes>::iterator I = nodeToAttributesMap.begin(), E = nodeToAttributesMap.end(); I != E; ++I) {
    calculateALAP(I->first, MII, maxASAP, (MSchedGraphNode*) 0);
    visitedNodes.clear();
  }

  //Calculate MOB which depends on ASAP being totally calculated, also do depth and height
  for(std::map<MSchedGraphNode*, MSNodeAttributes>::iterator I = nodeToAttributesMap.begin(), E = nodeToAttributesMap.end(); I != E; ++I) {
    (I->second).MOB = std::max(0,(I->second).ALAP - (I->second).ASAP);

    DEBUG(std::cerr << "MOB: " << (I->second).MOB << " (" << *(I->first) << ")\n");
    calculateDepth(I->first, (MSchedGraphNode*) 0);
    calculateHeight(I->first, (MSchedGraphNode*) 0);
  }


}

/// ignoreEdge - Checks to see if this edge of a recurrence should be ignored or not
bool ModuloSchedulingPass::ignoreEdge(MSchedGraphNode *srcNode, MSchedGraphNode *destNode) {
  if(destNode == 0 || srcNode ==0)
    return false;

  bool findEdge = edgesToIgnore.count(std::make_pair(srcNode, destNode->getInEdgeNum(srcNode)));

  DEBUG(std::cerr << "Ignoring edge? from: " << *srcNode << " to " << *destNode << "\n");

  return findEdge;
}


/// calculateASAP - Calculates the
int  ModuloSchedulingPass::calculateASAP(MSchedGraphNode *node, int MII, MSchedGraphNode *destNode) {

  DEBUG(std::cerr << "Calculating ASAP for " << *node << "\n");

  //Get current node attributes
  MSNodeAttributes &attributes = nodeToAttributesMap.find(node)->second;

  if(attributes.ASAP != -1)
    return attributes.ASAP;

  int maxPredValue = 0;

  //Iterate over all of the predecessors and find max
  for(MSchedGraphNode::pred_iterator P = node->pred_begin(), E = node->pred_end(); P != E; ++P) {

    //Only process if we are not ignoring the edge
    if(!ignoreEdge(*P, node)) {
      int predASAP = -1;
      predASAP = calculateASAP(*P, MII, node);

      assert(predASAP != -1 && "ASAP has not been calculated");
      int iteDiff = node->getInEdge(*P).getIteDiff();

      int currentPredValue = predASAP + (*P)->getLatency() - (iteDiff * MII);
      DEBUG(std::cerr << "pred ASAP: " << predASAP << ", iteDiff: " << iteDiff << ", PredLatency: " << (*P)->getLatency() << ", Current ASAP pred: " << currentPredValue << "\n");
      maxPredValue = std::max(maxPredValue, currentPredValue);
    }
  }

  attributes.ASAP = maxPredValue;

  DEBUG(std::cerr << "ASAP: " << attributes.ASAP << " (" << *node << ")\n");

  return maxPredValue;
}


int ModuloSchedulingPass::calculateALAP(MSchedGraphNode *node, int MII,
                                        int maxASAP, MSchedGraphNode *srcNode) {

  DEBUG(std::cerr << "Calculating ALAP for " << *node << "\n");

  MSNodeAttributes &attributes = nodeToAttributesMap.find(node)->second;

  if(attributes.ALAP != -1)
    return attributes.ALAP;

  if(node->hasSuccessors()) {

    //Trying to deal with the issue where the node has successors, but
    //we are ignoring all of the edges to them. So this is my hack for
    //now.. there is probably a more elegant way of doing this (FIXME)
    bool processedOneEdge = false;

    //FIXME, set to something high to start
    int minSuccValue = 9999999;

    //Iterate over all of the predecessors and fine max
    for(MSchedGraphNode::succ_iterator P = node->succ_begin(),
          E = node->succ_end(); P != E; ++P) {

      //Only process if we are not ignoring the edge
      if(!ignoreEdge(node, *P)) {
        processedOneEdge = true;
        int succALAP = -1;
        succALAP = calculateALAP(*P, MII, maxASAP, node);

        assert(succALAP != -1 && "Successors ALAP should have been caclulated");

        int iteDiff = P.getEdge().getIteDiff();

        int currentSuccValue = succALAP - node->getLatency() + iteDiff * MII;

        DEBUG(std::cerr << "succ ALAP: " << succALAP << ", iteDiff: " << iteDiff << ", SuccLatency: " << (*P)->getLatency() << ", Current ALAP succ: " << currentSuccValue << "\n");

        minSuccValue = std::min(minSuccValue, currentSuccValue);
      }
    }

    if(processedOneEdge)
        attributes.ALAP = minSuccValue;

    else
      attributes.ALAP = maxASAP;
  }
  else
    attributes.ALAP = maxASAP;

  DEBUG(std::cerr << "ALAP: " << attributes.ALAP << " (" << *node << ")\n");

  if(attributes.ALAP < 0)
    attributes.ALAP = 0;

  return attributes.ALAP;
}

int ModuloSchedulingPass::findMaxASAP() {
  int maxASAP = 0;

  for(std::map<MSchedGraphNode*, MSNodeAttributes>::iterator I = nodeToAttributesMap.begin(),
        E = nodeToAttributesMap.end(); I != E; ++I)
    maxASAP = std::max(maxASAP, I->second.ASAP);
  return maxASAP;
}


int ModuloSchedulingPass::calculateHeight(MSchedGraphNode *node,MSchedGraphNode *srcNode) {

  MSNodeAttributes &attributes = nodeToAttributesMap.find(node)->second;

  if(attributes.height != -1)
    return attributes.height;

  int maxHeight = 0;

  //Iterate over all of the predecessors and find max
  for(MSchedGraphNode::succ_iterator P = node->succ_begin(),
        E = node->succ_end(); P != E; ++P) {


    if(!ignoreEdge(node, *P)) {
      int succHeight = calculateHeight(*P, node);

      assert(succHeight != -1 && "Successors Height should have been caclulated");

      int currentHeight = succHeight + node->getLatency();
      maxHeight = std::max(maxHeight, currentHeight);
    }
  }
  attributes.height = maxHeight;
  DEBUG(std::cerr << "Height: " << attributes.height << " (" << *node << ")\n");
  return maxHeight;
}


int ModuloSchedulingPass::calculateDepth(MSchedGraphNode *node,
                                          MSchedGraphNode *destNode) {

  MSNodeAttributes &attributes = nodeToAttributesMap.find(node)->second;

  if(attributes.depth != -1)
    return attributes.depth;

  int maxDepth = 0;

  //Iterate over all of the predecessors and fine max
  for(MSchedGraphNode::pred_iterator P = node->pred_begin(), E = node->pred_end(); P != E; ++P) {

    if(!ignoreEdge(*P, node)) {
      int predDepth = -1;
      predDepth = calculateDepth(*P, node);

      assert(predDepth != -1 && "Predecessors ASAP should have been caclulated");

      int currentDepth = predDepth + (*P)->getLatency();
      maxDepth = std::max(maxDepth, currentDepth);
    }
  }
  attributes.depth = maxDepth;

  DEBUG(std::cerr << "Depth: " << attributes.depth << " (" << *node << "*)\n");
  return maxDepth;
}



void ModuloSchedulingPass::addReccurrence(std::vector<MSchedGraphNode*> &recurrence, int II, MSchedGraphNode *srcBENode, MSchedGraphNode *destBENode) {
  //Check to make sure that this recurrence is unique
  bool same = false;


  //Loop over all recurrences already in our list
  for(std::set<std::pair<int, std::vector<MSchedGraphNode*> > >::iterator R = recurrenceList.begin(), RE = recurrenceList.end(); R != RE; ++R) {

    bool all_same = true;
     //First compare size
    if(R->second.size() == recurrence.size()) {

      for(std::vector<MSchedGraphNode*>::const_iterator node = R->second.begin(), end = R->second.end(); node != end; ++node) {
        if(std::find(recurrence.begin(), recurrence.end(), *node) == recurrence.end()) {
          all_same = all_same && false;
          break;
        }
        else
          all_same = all_same && true;
      }
      if(all_same) {
        same = true;
        break;
      }
    }
  }

  if(!same) {
    srcBENode = recurrence.back();
    destBENode = recurrence.front();

    //FIXME
    if(destBENode->getInEdge(srcBENode).getIteDiff() == 0) {
      //DEBUG(std::cerr << "NOT A BACKEDGE\n");
      //find actual backedge HACK HACK
      for(unsigned i=0; i< recurrence.size()-1; ++i) {
        if(recurrence[i+1]->getInEdge(recurrence[i]).getIteDiff() == 1) {
          srcBENode = recurrence[i];
          destBENode = recurrence[i+1];
          break;
        }

      }

    }
    DEBUG(std::cerr << "Back Edge to Remove: " << *srcBENode << " to " << *destBENode << "\n");
    edgesToIgnore.insert(std::make_pair(srcBENode, destBENode->getInEdgeNum(srcBENode)));
    recurrenceList.insert(std::make_pair(II, recurrence));
  }

}

int CircCount;

void ModuloSchedulingPass::unblock(MSchedGraphNode *u, std::set<MSchedGraphNode*> &blocked,
             std::map<MSchedGraphNode*, std::set<MSchedGraphNode*> > &B) {

  //Unblock u
  DEBUG(std::cerr << "Unblocking: " << *u << "\n");
  blocked.erase(u);

  //std::set<MSchedGraphNode*> toErase;
  while (!B[u].empty()) {
    MSchedGraphNode *W = *B[u].begin();
    B[u].erase(W);
    //toErase.insert(*W);
    DEBUG(std::cerr << "Removed: " << *W << "from B-List\n");
    if(blocked.count(W))
      unblock(W, blocked, B);
  }

}

bool ModuloSchedulingPass::circuit(MSchedGraphNode *v, std::vector<MSchedGraphNode*> &stack,
             std::set<MSchedGraphNode*> &blocked, std::vector<MSchedGraphNode*> &SCC,
             MSchedGraphNode *s, std::map<MSchedGraphNode*, std::set<MSchedGraphNode*> > &B,
                                   int II, std::map<MSchedGraphNode*, MSchedGraphNode*> &newNodes) {
  bool f = false;

  DEBUG(std::cerr << "Finding Circuits Starting with: ( " << v << ")"<< *v << "\n");

  //Push node onto the stack
  stack.push_back(v);

  //block this node
  blocked.insert(v);

  //Loop over all successors of node v that are in the scc, create Adjaceny list
  std::set<MSchedGraphNode*> AkV;
  for(MSchedGraphNode::succ_iterator I = v->succ_begin(), E = v->succ_end(); I != E; ++I) {
    if((std::find(SCC.begin(), SCC.end(), *I) != SCC.end())) {
      AkV.insert(*I);
    }
  }

  for(std::set<MSchedGraphNode*>::iterator I = AkV.begin(), E = AkV.end(); I != E; ++I) {
    if(*I == s) {
      //We have a circuit, so add it to our list
      addRecc(stack, newNodes);
      f = true;
    }
    else if(!blocked.count(*I)) {
      if(circuit(*I, stack, blocked, SCC, s, B, II, newNodes))
        f = true;
    }
    else
      DEBUG(std::cerr << "Blocked: " << **I << "\n");
  }


  if(f) {
    unblock(v, blocked, B);
  }
  else {
    for(std::set<MSchedGraphNode*>::iterator I = AkV.begin(), E = AkV.end(); I != E; ++I)
      B[*I].insert(v);

  }

  //Pop v
  stack.pop_back();

  return f;

}

void ModuloSchedulingPass::addRecc(std::vector<MSchedGraphNode*> &stack, std::map<MSchedGraphNode*, MSchedGraphNode*> &newNodes) {
  std::vector<MSchedGraphNode*> recc;
  //Dump recurrence for now
  DEBUG(std::cerr << "Starting Recc\n");

  int totalDelay = 0;
  int totalDistance = 0;
  MSchedGraphNode *lastN = 0;
  MSchedGraphNode *start = 0;
  MSchedGraphNode *end = 0;

  //Loop over recurrence, get delay and distance
  for(std::vector<MSchedGraphNode*>::iterator N = stack.begin(), NE = stack.end(); N != NE; ++N) {
    DEBUG(std::cerr << **N << "\n");
    totalDelay += (*N)->getLatency();
    if(lastN) {
      int iteDiff = (*N)->getInEdge(lastN).getIteDiff();
      totalDistance += iteDiff;

      if(iteDiff > 0) {
        start = lastN;
        end = *N;
      }
    }
    //Get the original node
    lastN = *N;
    recc.push_back(newNodes[*N]);


  }

  //Get the loop edge
  totalDistance += lastN->getIteDiff(*stack.begin());

  DEBUG(std::cerr << "End Recc\n");
  CircCount++;

  if(start && end) {
    //Insert reccurrence into the list
    DEBUG(std::cerr << "Ignore Edge from!!: " << *start << " to " << *end << "\n");
    edgesToIgnore.insert(std::make_pair(newNodes[start], (newNodes[end])->getInEdgeNum(newNodes[start])));
  }
  else {
    //Insert reccurrence into the list
    DEBUG(std::cerr << "Ignore Edge from: " << *lastN << " to " << **stack.begin() << "\n");
    edgesToIgnore.insert(std::make_pair(newNodes[lastN], newNodes[(*stack.begin())]->getInEdgeNum(newNodes[lastN])));

  }
  //Adjust II until we get close to the inequality delay - II*distance <= 0
  int RecMII = II; //Starting value
  int value = totalDelay-(RecMII * totalDistance);
  int lastII = II;
  while(value < 0) {

    lastII = RecMII;
    RecMII--;
    value = totalDelay-(RecMII * totalDistance);
  }

  recurrenceList.insert(std::make_pair(lastII, recc));

}

void ModuloSchedulingPass::addSCC(std::vector<MSchedGraphNode*> &SCC, std::map<MSchedGraphNode*, MSchedGraphNode*> &newNodes) {

  int totalDelay = 0;
  int totalDistance = 0;
  std::vector<MSchedGraphNode*> recc;
  MSchedGraphNode *start = 0;
  MSchedGraphNode *end = 0;

  //Loop over recurrence, get delay and distance
  for(std::vector<MSchedGraphNode*>::iterator N = SCC.begin(), NE = SCC.end(); N != NE; ++N) {
    DEBUG(std::cerr << **N << "\n");
    totalDelay += (*N)->getLatency();

    for(unsigned i = 0; i < (*N)->succ_size(); ++i) {
      MSchedGraphEdge *edge = (*N)->getSuccessor(i);
      if(find(SCC.begin(), SCC.end(), edge->getDest()) != SCC.end()) {
        totalDistance += edge->getIteDiff();
        if(edge->getIteDiff() > 0)
          if(!start && !end) {
            start = *N;
            end = edge->getDest();
          }

      }
    }


    //Get the original node
    recc.push_back(newNodes[*N]);


  }

  DEBUG(std::cerr << "End Recc\n");
  CircCount++;

  assert( (start && end) && "Must have start and end node to ignore edge for SCC");

  if(start && end) {
    //Insert reccurrence into the list
    DEBUG(std::cerr << "Ignore Edge from!!: " << *start << " to " << *end << "\n");
    edgesToIgnore.insert(std::make_pair(newNodes[start], (newNodes[end])->getInEdgeNum(newNodes[start])));
  }

  int lastII = totalDelay / totalDistance;


  recurrenceList.insert(std::make_pair(lastII, recc));

}

void ModuloSchedulingPass::findAllCircuits(MSchedGraph *g, int II) {

  CircCount = 0;

  //Keep old to new node mapping information
  std::map<MSchedGraphNode*, MSchedGraphNode*> newNodes;

  //copy the graph
  MSchedGraph *MSG = new MSchedGraph(*g, newNodes);

  DEBUG(std::cerr << "Finding All Circuits\n");

  //Set of blocked nodes
  std::set<MSchedGraphNode*> blocked;

  //Stack holding current circuit
  std::vector<MSchedGraphNode*> stack;

  //Map for B Lists
  std::map<MSchedGraphNode*, std::set<MSchedGraphNode*> > B;

  //current node
  MSchedGraphNode *s;


  //Iterate over the graph until its down to one node or empty
  while(MSG->size() > 1) {

    //Write Graph out to file
    //WriteGraphToFile(std::cerr, "Graph" + utostr(MSG->size()), MSG);

    DEBUG(std::cerr << "Graph Size: " << MSG->size() << "\n");
    DEBUG(std::cerr << "Finding strong component Vk with least vertex\n");

    //Iterate over all the SCCs in the graph
    std::set<MSchedGraphNode*> Visited;
    std::vector<MSchedGraphNode*> Vk;
    MSchedGraphNode* s = 0;
    int numEdges = 0;

    //Find scc with the least vertex
    for (MSchedGraph::iterator GI = MSG->begin(), E = MSG->end(); GI != E; ++GI)
      if (Visited.insert(GI->second).second) {
        for (scc_iterator<MSchedGraphNode*> SCCI = scc_begin(GI->second),
               E = scc_end(GI->second); SCCI != E; ++SCCI) {
          std::vector<MSchedGraphNode*> &nextSCC = *SCCI;

          if (Visited.insert(nextSCC[0]).second) {
            Visited.insert(nextSCC.begin()+1, nextSCC.end());

            if(nextSCC.size() > 1) {
              std::cerr << "SCC size: " << nextSCC.size() << "\n";

              for(unsigned i = 0; i < nextSCC.size(); ++i) {
                //Loop over successor and see if in scc, then count edge
                MSchedGraphNode *node = nextSCC[i];
                for(MSchedGraphNode::succ_iterator S = node->succ_begin(), SE = node->succ_end(); S != SE; ++S) {
                  if(find(nextSCC.begin(), nextSCC.end(), *S) != nextSCC.end())
                    numEdges++;
                }
              }
              std::cerr << "Num Edges: " << numEdges << "\n";
            }

            //Ignore self loops
            if(nextSCC.size() > 1) {

              //Get least vertex in Vk
              if(!s) {
                s = nextSCC[0];
                Vk = nextSCC;
              }

              for(unsigned i = 0; i < nextSCC.size(); ++i) {
                if(nextSCC[i] < s) {
                  s = nextSCC[i];
                  Vk = nextSCC;
                }
              }
            }
          }
        }
      }



    //Process SCC
    DEBUG(for(std::vector<MSchedGraphNode*>::iterator N = Vk.begin(), NE = Vk.end();
              N != NE; ++N) { std::cerr << *((*N)->getInst()); });

    //Iterate over all nodes in this scc
    for(std::vector<MSchedGraphNode*>::iterator N = Vk.begin(), NE = Vk.end();
        N != NE; ++N) {
      blocked.erase(*N);
      B[*N].clear();
    }
    if(Vk.size() > 1) {
      if(numEdges < 98)
        circuit(s, stack, blocked, Vk, s, B, II, newNodes);
      else
        addSCC(Vk, newNodes);

      //Delete nodes from the graph
      //Find all nodes up to s and delete them
      std::vector<MSchedGraphNode*> nodesToRemove;
      nodesToRemove.push_back(s);
      for(MSchedGraph::iterator N = MSG->begin(), NE = MSG->end(); N != NE; ++N) {
        if(N->second < s )
            nodesToRemove.push_back(N->second);
      }
      for(std::vector<MSchedGraphNode*>::iterator N = nodesToRemove.begin(), NE = nodesToRemove.end(); N != NE; ++N) {
        DEBUG(std::cerr << "Deleting Node: " << **N << "\n");
        MSG->deleteNode(*N);
      }
    }
    else
      break;
  }
  DEBUG(std::cerr << "Num Circuits found: " << CircCount << "\n");
}


void ModuloSchedulingPass::findAllReccurrences(MSchedGraphNode *node,
                                               std::vector<MSchedGraphNode*> &visitedNodes,
                                               int II) {


  if(std::find(visitedNodes.begin(), visitedNodes.end(), node) != visitedNodes.end()) {
    std::vector<MSchedGraphNode*> recurrence;
    bool first = true;
    int delay = 0;
    int distance = 0;
    int RecMII = II; //Starting value
    MSchedGraphNode *last = node;
    MSchedGraphNode *srcBackEdge = 0;
    MSchedGraphNode *destBackEdge = 0;



    for(std::vector<MSchedGraphNode*>::iterator I = visitedNodes.begin(), E = visitedNodes.end();
        I !=E; ++I) {

      if(*I == node)
        first = false;
      if(first)
        continue;

      delay = delay + (*I)->getLatency();

      if(*I != node) {
        int diff = (*I)->getInEdge(last).getIteDiff();
        distance += diff;
        if(diff > 0) {
          srcBackEdge = last;
          destBackEdge = *I;
        }
      }

      recurrence.push_back(*I);
      last = *I;
    }



    //Get final distance calc
    distance += node->getInEdge(last).getIteDiff();
    DEBUG(std::cerr << "Reccurrence Distance: " << distance << "\n");

    //Adjust II until we get close to the inequality delay - II*distance <= 0

    int value = delay-(RecMII * distance);
    int lastII = II;
    while(value <= 0) {

      lastII = RecMII;
      RecMII--;
      value = delay-(RecMII * distance);
    }


    DEBUG(std::cerr << "Final II for this recurrence: " << lastII << "\n");
    addReccurrence(recurrence, lastII, srcBackEdge, destBackEdge);
    assert(distance != 0 && "Recurrence distance should not be zero");
    return;
  }

  unsigned count = 0;
  for(MSchedGraphNode::succ_iterator I = node->succ_begin(), E = node->succ_end(); I != E; ++I) {
    visitedNodes.push_back(node);
    //if(!edgesToIgnore.count(std::make_pair(node, count)))
    findAllReccurrences(*I, visitedNodes, II);
    visitedNodes.pop_back();
    count++;
  }
}

void ModuloSchedulingPass::searchPath(MSchedGraphNode *node,
                                      std::vector<MSchedGraphNode*> &path,
                                      std::set<MSchedGraphNode*> &nodesToAdd,
                                     std::set<MSchedGraphNode*> &new_reccurrence) {
  //Push node onto the path
  path.push_back(node);

  //Loop over all successors and see if there is a path from this node to
  //a recurrence in the partial order, if so.. add all nodes to be added to recc
  for(MSchedGraphNode::succ_iterator S = node->succ_begin(), SE = node->succ_end(); S != SE;
      ++S) {

    //Check if we should ignore this edge first
    if(ignoreEdge(node,*S))
      continue;

    //check if successor is in this recurrence, we will get to it eventually
    if(new_reccurrence.count(*S))
      continue;

    //If this node exists in a recurrence already in the partial
    //order, then add all nodes in the path to the set of nodes to add
     //Check if its already in our partial order, if not add it to the
     //final vector
    bool found = false;
    for(std::vector<std::set<MSchedGraphNode*> >::iterator PO = partialOrder.begin(),
          PE = partialOrder.end(); PO != PE; ++PO) {

      if(PO->count(*S)) {
        found = true;
        break;
      }
    }

    if(!found) {
      nodesToAdd.insert(*S);
      searchPath(*S, path, nodesToAdd, new_reccurrence);
    }
  }

  //Pop Node off the path
  path.pop_back();
}

void ModuloSchedulingPass::pathToRecc(MSchedGraphNode *node,
                                      std::vector<MSchedGraphNode*> &path,
                                      std::set<MSchedGraphNode*> &poSet,
                                      std::set<MSchedGraphNode*> &lastNodes) {
  //Push node onto the path
  path.push_back(node);

  DEBUG(std::cerr << "Current node: " << *node << "\n");

  //Loop over all successors and see if there is a path from this node to
  //a recurrence in the partial order, if so.. add all nodes to be added to recc
  for(MSchedGraphNode::succ_iterator S = node->succ_begin(), SE = node->succ_end(); S != SE;
      ++S) {
    DEBUG(std::cerr << "Succ:" << **S << "\n");
    //Check if we should ignore this edge first
    if(ignoreEdge(node,*S))
      continue;

    if(poSet.count(*S)) {
      DEBUG(std::cerr << "Found path to recc from no pred\n");
      //Loop over path, if it exists in lastNodes, then add to poset, and remove from lastNodes
      for(std::vector<MSchedGraphNode*>::iterator I = path.begin(), IE = path.end(); I != IE; ++I) {
        if(lastNodes.count(*I)) {
          DEBUG(std::cerr << "Inserting node into recc: " << **I << "\n");
          poSet.insert(*I);
          lastNodes.erase(*I);
        }
      }
    }
    else
      pathToRecc(*S, path, poSet, lastNodes);
  }

  //Pop Node off the path
  path.pop_back();
}

void ModuloSchedulingPass::computePartialOrder() {

  TIME_REGION(X, "calculatePartialOrder");

  DEBUG(std::cerr << "Computing Partial Order\n");

  //Only push BA branches onto the final node order, we put other
  //branches after it FIXME: Should we really be pushing branches on
  //it a specific order instead of relying on BA being there?

  std::vector<MSchedGraphNode*> branches;

  //Steps to add a recurrence to the partial order 1) Find reccurrence
  //with the highest RecMII. Add it to the partial order.  2) For each
  //recurrence with decreasing RecMII, add it to the partial order
  //along with any nodes that connect this recurrence to recurrences
  //already in the partial order
  for(std::set<std::pair<int, std::vector<MSchedGraphNode*> > >::reverse_iterator
        I = recurrenceList.rbegin(), E=recurrenceList.rend(); I !=E; ++I) {

    std::set<MSchedGraphNode*> new_recurrence;

    //Loop through recurrence and remove any nodes already in the partial order
    for(std::vector<MSchedGraphNode*>::const_iterator N = I->second.begin(),
          NE = I->second.end(); N != NE; ++N) {

      bool found = false;
      for(std::vector<std::set<MSchedGraphNode*> >::iterator PO = partialOrder.begin(),
            PE = partialOrder.end(); PO != PE; ++PO) {
        if(PO->count(*N))
          found = true;
      }

      //Check if its a branch, and remove to handle special
      if(!found) {
        if((*N)->isBranch() && !(*N)->hasPredecessors()) {
          branches.push_back(*N);
        }
        else
          new_recurrence.insert(*N);
      }

    }


    if(new_recurrence.size() > 0) {

      std::vector<MSchedGraphNode*> path;
      std::set<MSchedGraphNode*> nodesToAdd;

      //Dump recc we are dealing with (minus nodes already in PO)
      DEBUG(std::cerr << "Recc: ");
      DEBUG(for(std::set<MSchedGraphNode*>::iterator R = new_recurrence.begin(), RE = new_recurrence.end(); R != RE; ++R) { std::cerr << **R ; });

      //Add nodes that connect this recurrence to recurrences in the partial path
      for(std::set<MSchedGraphNode*>::iterator N = new_recurrence.begin(),
          NE = new_recurrence.end(); N != NE; ++N)
        searchPath(*N, path, nodesToAdd, new_recurrence);

      //Add nodes to this recurrence if they are not already in the partial order
      for(std::set<MSchedGraphNode*>::iterator N = nodesToAdd.begin(), NE = nodesToAdd.end();
          N != NE; ++N) {
        bool found = false;
        for(std::vector<std::set<MSchedGraphNode*> >::iterator PO = partialOrder.begin(),
              PE = partialOrder.end(); PO != PE; ++PO) {
          if(PO->count(*N))
            found = true;
        }
        if(!found) {
          assert("FOUND CONNECTOR");
          new_recurrence.insert(*N);
        }
      }

      partialOrder.push_back(new_recurrence);


      //Dump out partial order
      DEBUG(for(std::vector<std::set<MSchedGraphNode*> >::iterator I = partialOrder.begin(),
                  E = partialOrder.end(); I !=E; ++I) {
              std::cerr << "Start set in PO\n";
              for(std::set<MSchedGraphNode*>::iterator J = I->begin(), JE = I->end(); J != JE; ++J)
                std::cerr << "PO:" << **J << "\n";
            });

    }
  }

  //Add any nodes that are not already in the partial order
  //Add them in a set, one set per connected component
  std::set<MSchedGraphNode*> lastNodes;
  std::set<MSchedGraphNode*> noPredNodes;
  for(std::map<MSchedGraphNode*, MSNodeAttributes>::iterator I = nodeToAttributesMap.begin(),
        E = nodeToAttributesMap.end(); I != E; ++I) {

    bool found = false;

    //Check if its already in our partial order, if not add it to the final vector
    for(std::vector<std::set<MSchedGraphNode*> >::iterator PO = partialOrder.begin(),
          PE = partialOrder.end(); PO != PE; ++PO) {
      if(PO->count(I->first))
        found = true;
    }
    if(!found)
      lastNodes.insert(I->first);
  }

  //For each node w/out preds, see if there is a path to one of the
  //recurrences, and if so add them to that current recc
  /*for(std::set<MSchedGraphNode*>::iterator N = noPredNodes.begin(), NE = noPredNodes.end();
      N != NE; ++N) {
    DEBUG(std::cerr << "No Pred Path from: " << **N << "\n");
    for(std::vector<std::set<MSchedGraphNode*> >::iterator PO = partialOrder.begin(),
          PE = partialOrder.end(); PO != PE; ++PO) {
      std::vector<MSchedGraphNode*> path;
      pathToRecc(*N, path, *PO, lastNodes);
    }
    }*/


  //Break up remaining nodes that are not in the partial order
  ///into their connected compoenents
    while(lastNodes.size() > 0) {
      std::set<MSchedGraphNode*> ccSet;
      connectedComponentSet(*(lastNodes.begin()),ccSet, lastNodes);
      if(ccSet.size() > 0)
        partialOrder.push_back(ccSet);
    }


  //Clean up branches by putting them in final order
    assert(branches.size() == 0 && "We should not have any branches in our graph");
}


void ModuloSchedulingPass::connectedComponentSet(MSchedGraphNode *node, std::set<MSchedGraphNode*> &ccSet, std::set<MSchedGraphNode*> &lastNodes) {

//Add to final set
  if( !ccSet.count(node) && lastNodes.count(node)) {
    lastNodes.erase(node);
    ccSet.insert(node);
  }
  else
    return;

  //Loop over successors and recurse if we have not seen this node before
  for(MSchedGraphNode::succ_iterator node_succ = node->succ_begin(), end=node->succ_end(); node_succ != end; ++node_succ) {
    connectedComponentSet(*node_succ, ccSet, lastNodes);
  }

}

void ModuloSchedulingPass::predIntersect(std::set<MSchedGraphNode*> &CurrentSet, std::set<MSchedGraphNode*> &IntersectResult) {

  for(unsigned j=0; j < FinalNodeOrder.size(); ++j) {
    for(MSchedGraphNode::pred_iterator P = FinalNodeOrder[j]->pred_begin(),
          E = FinalNodeOrder[j]->pred_end(); P != E; ++P) {

      //Check if we are supposed to ignore this edge or not
      if(ignoreEdge(*P,FinalNodeOrder[j]))
        continue;

      if(CurrentSet.count(*P))
        if(std::find(FinalNodeOrder.begin(), FinalNodeOrder.end(), *P) == FinalNodeOrder.end())
          IntersectResult.insert(*P);
    }
  }
}





void ModuloSchedulingPass::succIntersect(std::set<MSchedGraphNode*> &CurrentSet, std::set<MSchedGraphNode*> &IntersectResult) {

  for(unsigned j=0; j < FinalNodeOrder.size(); ++j) {
    for(MSchedGraphNode::succ_iterator P = FinalNodeOrder[j]->succ_begin(),
          E = FinalNodeOrder[j]->succ_end(); P != E; ++P) {

      //Check if we are supposed to ignore this edge or not
      if(ignoreEdge(FinalNodeOrder[j],*P))
        continue;

      if(CurrentSet.count(*P))
        if(std::find(FinalNodeOrder.begin(), FinalNodeOrder.end(), *P) == FinalNodeOrder.end())
          IntersectResult.insert(*P);
    }
  }
}

void dumpIntersection(std::set<MSchedGraphNode*> &IntersectCurrent) {
  std::cerr << "Intersection (";
  for(std::set<MSchedGraphNode*>::iterator I = IntersectCurrent.begin(), E = IntersectCurrent.end(); I != E; ++I)
    std::cerr << **I << ", ";
  std::cerr << ")\n";
}



void ModuloSchedulingPass::orderNodes() {

  TIME_REGION(X, "orderNodes");

  int BOTTOM_UP = 0;
  int TOP_DOWN = 1;

  //Set default order
  int order = BOTTOM_UP;


  //Loop over all the sets and place them in the final node order
  for(std::vector<std::set<MSchedGraphNode*> >::iterator CurrentSet = partialOrder.begin(), E= partialOrder.end(); CurrentSet != E; ++CurrentSet) {

    DEBUG(std::cerr << "Processing set in S\n");
    DEBUG(dumpIntersection(*CurrentSet));

    //Result of intersection
    std::set<MSchedGraphNode*> IntersectCurrent;

    predIntersect(*CurrentSet, IntersectCurrent);

    //If the intersection of predecessor and current set is not empty
    //sort nodes bottom up
    if(IntersectCurrent.size() != 0) {
      DEBUG(std::cerr << "Final Node Order Predecessors and Current Set interesection is NOT empty\n");
      order = BOTTOM_UP;
    }
    //If empty, use successors
    else {
      DEBUG(std::cerr << "Final Node Order Predecessors and Current Set interesection is empty\n");

      succIntersect(*CurrentSet, IntersectCurrent);

      //sort top-down
      if(IntersectCurrent.size() != 0) {
         DEBUG(std::cerr << "Final Node Order Successors and Current Set interesection is NOT empty\n");
        order = TOP_DOWN;
      }
      else {
        DEBUG(std::cerr << "Final Node Order Successors and Current Set interesection is empty\n");
        //Find node with max ASAP in current Set
        MSchedGraphNode *node;
        int maxASAP = 0;
        DEBUG(std::cerr << "Using current set of size " << CurrentSet->size() << "to find max ASAP\n");
        for(std::set<MSchedGraphNode*>::iterator J = CurrentSet->begin(), JE = CurrentSet->end(); J != JE; ++J) {
          //Get node attributes
          MSNodeAttributes nodeAttr= nodeToAttributesMap.find(*J)->second;
          //assert(nodeAttr != nodeToAttributesMap.end() && "Node not in attributes map!");

          if(maxASAP <= nodeAttr.ASAP) {
            maxASAP = nodeAttr.ASAP;
            node = *J;
          }
        }
        assert(node != 0 && "In node ordering node should not be null");
        IntersectCurrent.insert(node);
        order = BOTTOM_UP;
      }
    }

    //Repeat until all nodes are put into the final order from current set
    while(IntersectCurrent.size() > 0) {

      if(order == TOP_DOWN) {
        DEBUG(std::cerr << "Order is TOP DOWN\n");

        while(IntersectCurrent.size() > 0) {
          DEBUG(std::cerr << "Intersection is not empty, so find heighest height\n");

          int MOB = 0;
          int height = 0;
          MSchedGraphNode *highestHeightNode = *(IntersectCurrent.begin());

          //Find node in intersection with highest heigh and lowest MOB
          for(std::set<MSchedGraphNode*>::iterator I = IntersectCurrent.begin(),
                E = IntersectCurrent.end(); I != E; ++I) {

            //Get current nodes properties
            MSNodeAttributes nodeAttr= nodeToAttributesMap.find(*I)->second;

            if(height < nodeAttr.height) {
              highestHeightNode = *I;
              height = nodeAttr.height;
              MOB = nodeAttr.MOB;
            }
            else if(height ==  nodeAttr.height) {
              if(MOB > nodeAttr.height) {
                highestHeightNode = *I;
                height =  nodeAttr.height;
                MOB = nodeAttr.MOB;
              }
            }
          }

          //Append our node with greatest height to the NodeOrder
          if(std::find(FinalNodeOrder.begin(), FinalNodeOrder.end(), highestHeightNode) == FinalNodeOrder.end()) {
            DEBUG(std::cerr << "Adding node to Final Order: " << *highestHeightNode << "\n");
            FinalNodeOrder.push_back(highestHeightNode);
          }

          //Remove V from IntersectOrder
          IntersectCurrent.erase(std::find(IntersectCurrent.begin(),
                                      IntersectCurrent.end(), highestHeightNode));


          //Intersect V's successors with CurrentSet
          for(MSchedGraphNode::succ_iterator P = highestHeightNode->succ_begin(),
                E = highestHeightNode->succ_end(); P != E; ++P) {
            //if(lower_bound(CurrentSet->begin(),
            //     CurrentSet->end(), *P) != CurrentSet->end()) {
            if(std::find(CurrentSet->begin(), CurrentSet->end(), *P) != CurrentSet->end()) {
              if(ignoreEdge(highestHeightNode, *P))
                continue;
              //If not already in Intersect, add
              if(!IntersectCurrent.count(*P))
                IntersectCurrent.insert(*P);
            }
          }
        } //End while loop over Intersect Size

        //Change direction
        order = BOTTOM_UP;

        //Reset Intersect to reflect changes in OrderNodes
        IntersectCurrent.clear();
        predIntersect(*CurrentSet, IntersectCurrent);

      } //End If TOP_DOWN

        //Begin if BOTTOM_UP
      else {
        DEBUG(std::cerr << "Order is BOTTOM UP\n");
        while(IntersectCurrent.size() > 0) {
          DEBUG(std::cerr << "Intersection of size " << IntersectCurrent.size() << ", finding highest depth\n");

          //dump intersection
          DEBUG(dumpIntersection(IntersectCurrent));
          //Get node with highest depth, if a tie, use one with lowest
          //MOB
          int MOB = 0;
          int depth = 0;
          MSchedGraphNode *highestDepthNode = *(IntersectCurrent.begin());

          for(std::set<MSchedGraphNode*>::iterator I = IntersectCurrent.begin(),
                E = IntersectCurrent.end(); I != E; ++I) {
            //Find node attribute in graph
            MSNodeAttributes nodeAttr= nodeToAttributesMap.find(*I)->second;

            if(depth < nodeAttr.depth) {
              highestDepthNode = *I;
              depth = nodeAttr.depth;
              MOB = nodeAttr.MOB;
            }
            else if(depth == nodeAttr.depth) {
              if(MOB > nodeAttr.MOB) {
                highestDepthNode = *I;
                depth = nodeAttr.depth;
                MOB = nodeAttr.MOB;
              }
            }
          }



          //Append highest depth node to the NodeOrder
           if(std::find(FinalNodeOrder.begin(), FinalNodeOrder.end(), highestDepthNode) == FinalNodeOrder.end()) {
             DEBUG(std::cerr << "Adding node to Final Order: " << *highestDepthNode << "\n");
             FinalNodeOrder.push_back(highestDepthNode);
           }
          //Remove heightestDepthNode from IntersectOrder
           IntersectCurrent.erase(highestDepthNode);


          //Intersect heightDepthNode's pred with CurrentSet
          for(MSchedGraphNode::pred_iterator P = highestDepthNode->pred_begin(),
                E = highestDepthNode->pred_end(); P != E; ++P) {
            if(CurrentSet->count(*P)) {
              if(ignoreEdge(*P, highestDepthNode))
                continue;

            //If not already in Intersect, add
            if(!IntersectCurrent.count(*P))
              IntersectCurrent.insert(*P);
            }
          }

        } //End while loop over Intersect Size

          //Change order
        order = TOP_DOWN;

        //Reset IntersectCurrent to reflect changes in OrderNodes
        IntersectCurrent.clear();
        succIntersect(*CurrentSet, IntersectCurrent);
        } //End if BOTTOM_DOWN

      DEBUG(std::cerr << "Current Intersection Size: " << IntersectCurrent.size() << "\n");
    }
    //End Wrapping while loop
    DEBUG(std::cerr << "Ending Size of Current Set: " << CurrentSet->size() << "\n");
  }//End for over all sets of nodes

  //FIXME: As the algorithm stands it will NEVER add an instruction such as ba (with no
  //data dependencies) to the final order. We add this manually. It will always be
  //in the last set of S since its not part of a recurrence
    //Loop over all the sets and place them in the final node order
  std::vector<std::set<MSchedGraphNode*> > ::reverse_iterator LastSet = partialOrder.rbegin();
  for(std::set<MSchedGraphNode*>::iterator CurrentNode = LastSet->begin(), LastNode = LastSet->end();
      CurrentNode != LastNode; ++CurrentNode) {
    if((*CurrentNode)->getInst()->getOpcode() == V9::BA)
      FinalNodeOrder.push_back(*CurrentNode);
  }
  //Return final Order
  //return FinalNodeOrder;
}

bool ModuloSchedulingPass::computeSchedule(const MachineBasicBlock *BB, MSchedGraph *MSG) {

  TIME_REGION(X, "computeSchedule");

  bool success = false;

  //FIXME: Should be set to max II of the original loop
  //Cap II in order to prevent infinite loop
  int capII = MSG->totalDelay();

  while(!success) {

    //Keep track of branches, but do not insert into the schedule
    std::vector<MSchedGraphNode*> branches;

    //Loop over the final node order and process each node
    for(std::vector<MSchedGraphNode*>::iterator I = FinalNodeOrder.begin(),
          E = FinalNodeOrder.end(); I != E; ++I) {

      //CalculateEarly and Late start
      bool initialLSVal = false;
      bool initialESVal = false;
      int EarlyStart = 0;
      int LateStart = 0;
      bool hasSucc = false;
      bool hasPred = false;
      bool sched;

      if((*I)->isBranch())
        if((*I)->hasPredecessors())
          sched = true;
        else
          sched = false;
      else
        sched = true;

      if(sched) {
        //Loop over nodes in the schedule and determine if they are predecessors
        //or successors of the node we are trying to schedule
        for(MSSchedule::schedule_iterator nodesByCycle = schedule.begin(), nodesByCycleEnd = schedule.end();
            nodesByCycle != nodesByCycleEnd; ++nodesByCycle) {

          //For this cycle, get the vector of nodes schedule and loop over it
          for(std::vector<MSchedGraphNode*>::iterator schedNode = nodesByCycle->second.begin(), SNE = nodesByCycle->second.end(); schedNode != SNE; ++schedNode) {

            if((*I)->isPredecessor(*schedNode)) {
              int diff = (*I)->getInEdge(*schedNode).getIteDiff();
              int ES_Temp = nodesByCycle->first + (*schedNode)->getLatency() - diff * II;
              DEBUG(std::cerr << "Diff: " << diff << " Cycle: " << nodesByCycle->first << "\n");
              DEBUG(std::cerr << "Temp EarlyStart: " << ES_Temp << " Prev EarlyStart: " << EarlyStart << "\n");
              if(initialESVal)
                EarlyStart = std::max(EarlyStart, ES_Temp);
              else {
                EarlyStart = ES_Temp;
                initialESVal = true;
              }
              hasPred = true;
            }
            if((*I)->isSuccessor(*schedNode)) {
              int diff = (*schedNode)->getInEdge(*I).getIteDiff();
              int LS_Temp = nodesByCycle->first - (*I)->getLatency() + diff * II;
              DEBUG(std::cerr << "Diff: " << diff << " Cycle: " << nodesByCycle->first << "\n");
              DEBUG(std::cerr << "Temp LateStart: " << LS_Temp << " Prev LateStart: " << LateStart << "\n");
              if(initialLSVal)
                LateStart = std::min(LateStart, LS_Temp);
              else {
                LateStart = LS_Temp;
                initialLSVal = true;
              }
              hasSucc = true;
            }
          }
        }
      }
      else {
        branches.push_back(*I);
        continue;
      }

      //Check if this node is a pred or succ to a branch, and restrict its placement
      //even though the branch is not in the schedule
      /*int count = branches.size();
      for(std::vector<MSchedGraphNode*>::iterator B = branches.begin(), BE = branches.end();
          B != BE; ++B) {
        if((*I)->isPredecessor(*B)) {
          int diff = (*I)->getInEdge(*B).getIteDiff();
          int ES_Temp = (II+count-1) + (*B)->getLatency() - diff * II;
          DEBUG(std::cerr << "Diff: " << diff << " Cycle: " << (II+count)-1 << "\n");
          DEBUG(std::cerr << "Temp EarlyStart: " << ES_Temp << " Prev EarlyStart: " << EarlyStart << "\n");
          EarlyStart = std::max(EarlyStart, ES_Temp);
          hasPred = true;
        }

        if((*I)->isSuccessor(*B)) {
          int diff = (*B)->getInEdge(*I).getIteDiff();
          int LS_Temp = (II+count-1) - (*I)->getLatency() + diff * II;
          DEBUG(std::cerr << "Diff: " << diff << " Cycle: " << (II+count-1) << "\n");
          DEBUG(std::cerr << "Temp LateStart: " << LS_Temp << " Prev LateStart: " << LateStart << "\n");
          LateStart = std::min(LateStart, LS_Temp);
          hasSucc = true;
        }

        count--;
      }*/

      //Check if the node has no pred or successors and set Early Start to its ASAP
      if(!hasSucc && !hasPred)
        EarlyStart = nodeToAttributesMap.find(*I)->second.ASAP;

      DEBUG(std::cerr << "Has Successors: " << hasSucc << ", Has Pred: " << hasPred << "\n");
      DEBUG(std::cerr << "EarlyStart: " << EarlyStart << ", LateStart: " << LateStart << "\n");

      //Now, try to schedule this node depending upon its pred and successor in the schedule
      //already
      if(!hasSucc && hasPred)
        success = scheduleNode(*I, EarlyStart, (EarlyStart + II -1));
      else if(!hasPred && hasSucc)
        success = scheduleNode(*I, LateStart, (LateStart - II +1));
      else if(hasPred && hasSucc) {
        if(EarlyStart > LateStart) {
        success = false;
          //LateStart = EarlyStart;
          DEBUG(std::cerr << "Early Start can not be later then the late start cycle, schedule fails\n");
        }
        else
          success = scheduleNode(*I, EarlyStart, std::min(LateStart, (EarlyStart + II -1)));
      }
      else
        success = scheduleNode(*I, EarlyStart, EarlyStart + II - 1);

      if(!success) {
        ++II;
        schedule.clear();
        break;
      }

    }

    if(success) {
      DEBUG(std::cerr << "Constructing Schedule Kernel\n");
      success = schedule.constructKernel(II, branches, indVarInstrs[BB]);
      DEBUG(std::cerr << "Done Constructing Schedule Kernel\n");
      if(!success) {
        ++II;
        schedule.clear();
      }
      DEBUG(std::cerr << "Final II: " << II << "\n");
    }


    if(II >= capII) {
      DEBUG(std::cerr << "Maximum II reached, giving up\n");
      return false;
    }

    assert(II < capII && "The II should not exceed the original loop number of cycles");
  }
  return true;
}


bool ModuloSchedulingPass::scheduleNode(MSchedGraphNode *node,
                                      int start, int end) {
  bool success = false;

  DEBUG(std::cerr << *node << " (Start Cycle: " << start << ", End Cycle: " << end << ")\n");

  //Make sure start and end are not negative
  //if(start < 0) {
  //start = 0;

  //}
  //if(end < 0)
  //end = 0;

  bool forward = true;
  if(start > end)
    forward = false;

  bool increaseSC = true;
  int cycle = start ;


  while(increaseSC) {

    increaseSC = false;

    increaseSC = schedule.insert(node, cycle, II);

    if(!increaseSC)
      return true;

    //Increment cycle to try again
    if(forward) {
      ++cycle;
      DEBUG(std::cerr << "Increase cycle: " << cycle << "\n");
      if(cycle > end)
        return false;
    }
    else {
      --cycle;
      DEBUG(std::cerr << "Decrease cycle: " << cycle << "\n");
      if(cycle < end)
        return false;
    }
  }

  return success;
}

void ModuloSchedulingPass::writePrologues(std::vector<MachineBasicBlock *> &prologues, MachineBasicBlock *origBB, std::vector<BasicBlock*> &llvm_prologues, std::map<const Value*, std::pair<const MachineInstr*, int> > &valuesToSave, std::map<Value*, std::map<int, Value*> > &newValues, std::map<Value*, MachineBasicBlock*> &newValLocation) {

  //Keep a map to easily know whats in the kernel
  std::map<int, std::set<const MachineInstr*> > inKernel;
  int maxStageCount = 0;

  //Keep a map of new values we consumed in case they need to be added back
  std::map<Value*, std::map<int, Value*> > consumedValues;

  MSchedGraphNode *branch = 0;
  MSchedGraphNode *BAbranch = 0;

  DEBUG(schedule.print(std::cerr));

  std::vector<MSchedGraphNode*> branches;

  for(MSSchedule::kernel_iterator I = schedule.kernel_begin(), E = schedule.kernel_end(); I != E; ++I) {
    maxStageCount = std::max(maxStageCount, I->second);

    //Put int the map so we know what instructions in each stage are in the kernel
    DEBUG(std::cerr << "Inserting instruction " << *(I->first) << " into map at stage " << I->second << "\n");
    inKernel[I->second].insert(I->first);
  }

  //Get target information to look at machine operands
  const TargetInstrInfo *mii = target.getInstrInfo();

 //Now write the prologues
  for(int i = 0; i < maxStageCount; ++i) {
    BasicBlock *llvmBB = new BasicBlock("PROLOGUE", (Function*) (origBB->getBasicBlock()->getParent()));
    MachineBasicBlock *machineBB = new MachineBasicBlock(llvmBB);

    DEBUG(std::cerr << "i=" << i << "\n");
    for(int j = i; j >= 0; --j) {
      for(MachineBasicBlock::const_iterator MI = origBB->begin(), ME = origBB->end(); ME != MI; ++MI) {
        if(inKernel[j].count(&*MI)) {
          MachineInstr *instClone = MI->clone();
          machineBB->push_back(instClone);

          //If its a branch, insert a nop
          if(mii->isBranch(instClone->getOpcode()))
            BuildMI(machineBB, V9::NOP, 0);


          DEBUG(std::cerr << "Cloning: " << *MI << "\n");

          //After cloning, we may need to save the value that this instruction defines
          for(unsigned opNum=0; opNum < MI->getNumOperands(); ++opNum) {
            Instruction *tmp;

            //get machine operand
            MachineOperand &mOp = instClone->getOperand(opNum);
            if(mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isDef()) {

              //Check if this is a value we should save
              if(valuesToSave.count(mOp.getVRegValue())) {
                //Save copy in tmpInstruction
                tmp = new TmpInstruction(mOp.getVRegValue());

                //Add TmpInstruction to safe LLVM Instruction MCFI
                MachineCodeForInstruction & tempMvec = MachineCodeForInstruction::get(defaultInst);
                tempMvec.addTemp((Value*) tmp);

                DEBUG(std::cerr << "Value: " << *(mOp.getVRegValue()) << " New Value: " << *tmp << " Stage: " << i << "\n");

                newValues[mOp.getVRegValue()][i]= tmp;
                newValLocation[tmp] = machineBB;

                DEBUG(std::cerr << "Machine Instr Operands: " << *(mOp.getVRegValue()) << ", 0, " << *tmp << "\n");

                //Create machine instruction and put int machineBB
                MachineInstr *saveValue;
                if(mOp.getVRegValue()->getType() == Type::FloatTy)
                  saveValue = BuildMI(machineBB, V9::FMOVS, 3).addReg(mOp.getVRegValue()).addRegDef(tmp);
                else if(mOp.getVRegValue()->getType() == Type::DoubleTy)
                  saveValue = BuildMI(machineBB, V9::FMOVD, 3).addReg(mOp.getVRegValue()).addRegDef(tmp);
                else
                  saveValue = BuildMI(machineBB, V9::ORr, 3).addReg(mOp.getVRegValue()).addImm(0).addRegDef(tmp);


                DEBUG(std::cerr << "Created new machine instr: " << *saveValue << "\n");
              }
            }

            //We may also need to update the value that we use if its from an earlier prologue
            if(j != 0) {
              if(mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isUse()) {
                if(newValues.count(mOp.getVRegValue())) {
                  if(newValues[mOp.getVRegValue()].count(i-1)) {
                    Value *oldV =  mOp.getVRegValue();
                    DEBUG(std::cerr << "Replaced this value: " << mOp.getVRegValue() << " With:" << (newValues[mOp.getVRegValue()][i-1]) << "\n");
                    //Update the operand with the right value
                    mOp.setValueReg(newValues[mOp.getVRegValue()][i-1]);

                    //Remove this value since we have consumed it
                    //NOTE: Should this only be done if j != maxStage?
                    consumedValues[oldV][i-1] = (newValues[oldV][i-1]);
                    DEBUG(std::cerr << "Deleted value: " << consumedValues[oldV][i-1] << "\n");
                    newValues[oldV].erase(i-1);
                  }
                }
                else
                  if(consumedValues.count(mOp.getVRegValue()))
                    assert(!consumedValues[mOp.getVRegValue()].count(i-1) && "Found a case where we need the value");
              }
            }
          }
        }
      }
    }

    MachineFunction *F = (((MachineBasicBlock*)origBB)->getParent());
    MachineFunction::BasicBlockListType &BL = F->getBasicBlockList();
    MachineFunction::BasicBlockListType::iterator BLI = origBB;
    assert(BLI != BL.end() && "Must find original BB in machine function\n");
    BL.insert(BLI,machineBB);
    prologues.push_back(machineBB);
    llvm_prologues.push_back(llvmBB);
  }
}

void ModuloSchedulingPass::writeEpilogues(std::vector<MachineBasicBlock *> &epilogues, const MachineBasicBlock *origBB, std::vector<BasicBlock*> &llvm_epilogues, std::map<const Value*, std::pair<const MachineInstr*, int> > &valuesToSave, std::map<Value*, std::map<int, Value*> > &newValues,std::map<Value*, MachineBasicBlock*> &newValLocation, std::map<Value*, std::map<int, Value*> > &kernelPHIs ) {

  std::map<int, std::set<const MachineInstr*> > inKernel;

  for(MSSchedule::kernel_iterator I = schedule.kernel_begin(), E = schedule.kernel_end(); I != E; ++I) {

    //Ignore the branch, we will handle this separately
    //if(I->first->isBranch())
    //continue;

    //Put int the map so we know what instructions in each stage are in the kernel
    inKernel[I->second].insert(I->first);
  }

  std::map<Value*, Value*> valPHIs;

  //some debug stuff, will remove later
  DEBUG(for(std::map<Value*, std::map<int, Value*> >::iterator V = newValues.begin(), E = newValues.end(); V !=E; ++V) {
    std::cerr << "Old Value: " << *(V->first) << "\n";
    for(std::map<int, Value*>::iterator I = V->second.begin(), IE = V->second.end(); I != IE; ++I)
      std::cerr << "Stage: " << I->first << " Value: " << *(I->second) << "\n";
  });

  //some debug stuff, will remove later
  DEBUG(for(std::map<Value*, std::map<int, Value*> >::iterator V = kernelPHIs.begin(), E = kernelPHIs.end(); V !=E; ++V) {
    std::cerr << "Old Value: " << *(V->first) << "\n";
    for(std::map<int, Value*>::iterator I = V->second.begin(), IE = V->second.end(); I != IE; ++I)
      std::cerr << "Stage: " << I->first << " Value: " << *(I->second) << "\n";
  });

  //Now write the epilogues
  for(int i = schedule.getMaxStage()-1; i >= 0; --i) {
    BasicBlock *llvmBB = new BasicBlock("EPILOGUE", (Function*) (origBB->getBasicBlock()->getParent()));
    MachineBasicBlock *machineBB = new MachineBasicBlock(llvmBB);

    DEBUG(std::cerr << " Epilogue #: " << i << "\n");


    std::map<Value*, int> inEpilogue;

     for(MachineBasicBlock::const_iterator MI = origBB->begin(), ME = origBB->end(); ME != MI; ++MI) {
      for(int j=schedule.getMaxStage(); j > i; --j) {
        if(inKernel[j].count(&*MI)) {
          DEBUG(std::cerr << "Cloning instruction " << *MI << "\n");
          MachineInstr *clone = MI->clone();

          //Update operands that need to use the result from the phi
          for(unsigned opNum=0; opNum < clone->getNumOperands(); ++opNum) {
            //get machine operand
            const MachineOperand &mOp = clone->getOperand(opNum);

            if((mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isUse())) {

              DEBUG(std::cerr << "Writing PHI for " << (mOp.getVRegValue()) << "\n");

              //If this is the last instructions for the max iterations ago, don't update operands
              if(inEpilogue.count(mOp.getVRegValue()))
                if(inEpilogue[mOp.getVRegValue()] == i)
                  continue;

              //Quickly write appropriate phis for this operand
              if(newValues.count(mOp.getVRegValue())) {
                if(newValues[mOp.getVRegValue()].count(i)) {
                  Instruction *tmp = new TmpInstruction(newValues[mOp.getVRegValue()][i]);

                  //Get machine code for this instruction
                  MachineCodeForInstruction & tempMvec = MachineCodeForInstruction::get(defaultInst);
                  tempMvec.addTemp((Value*) tmp);

                  //assert of no kernelPHI for this value
                  assert(kernelPHIs[mOp.getVRegValue()][i] !=0 && "Must have final kernel phi to construct epilogue phi");

                  MachineInstr *saveValue = BuildMI(machineBB, V9::PHI, 3).addReg(newValues[mOp.getVRegValue()][i]).addReg(kernelPHIs[mOp.getVRegValue()][i]).addRegDef(tmp);
                  DEBUG(std::cerr << "Resulting PHI: " << *saveValue << "\n");
                  valPHIs[mOp.getVRegValue()] = tmp;
                }
              }

              if(valPHIs.count(mOp.getVRegValue())) {
                //Update the operand in the cloned instruction
                clone->getOperand(opNum).setValueReg(valPHIs[mOp.getVRegValue()]);
              }
            }
            else if((mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isDef())) {
              inEpilogue[mOp.getVRegValue()] = i;
            }
          }
          machineBB->push_back(clone);
        }
      }
     }

     MachineFunction *F = (((MachineBasicBlock*)origBB)->getParent());
     MachineFunction::BasicBlockListType &BL = F->getBasicBlockList();
     MachineFunction::BasicBlockListType::iterator BLI = (MachineBasicBlock*) origBB;
     assert(BLI != BL.end() && "Must find original BB in machine function\n");
     BL.insert(BLI,machineBB);
     epilogues.push_back(machineBB);
     llvm_epilogues.push_back(llvmBB);

     DEBUG(std::cerr << "EPILOGUE #" << i << "\n");
     DEBUG(machineBB->print(std::cerr));
  }
}

void ModuloSchedulingPass::writeKernel(BasicBlock *llvmBB, MachineBasicBlock *machineBB, std::map<const Value*, std::pair<const MachineInstr*, int> > &valuesToSave, std::map<Value*, std::map<int, Value*> > &newValues, std::map<Value*, MachineBasicBlock*> &newValLocation, std::map<Value*, std::map<int, Value*> > &kernelPHIs) {

  //Keep track of operands that are read and saved from a previous iteration. The new clone
  //instruction will use the result of the phi instead.
  std::map<Value*, Value*> finalPHIValue;
  std::map<Value*, Value*> kernelValue;

  //Branches are a special case
  std::vector<MachineInstr*> branches;

  //Get target information to look at machine operands
  const TargetInstrInfo *mii = target.getInstrInfo();

  //Create TmpInstructions for the final phis
  for(MSSchedule::kernel_iterator I = schedule.kernel_begin(), E = schedule.kernel_end(); I != E; ++I) {

   DEBUG(std::cerr << "Stage: " << I->second << " Inst: " << *(I->first) << "\n";);

   //Clone instruction
   const MachineInstr *inst = I->first;
   MachineInstr *instClone = inst->clone();

   //Insert into machine basic block
   machineBB->push_back(instClone);

   if(mii->isBranch(instClone->getOpcode()))
     BuildMI(machineBB, V9::NOP, 0);

   DEBUG(std::cerr <<  "Cloned Inst: " << *instClone << "\n");

   //Loop over Machine Operands
   for(unsigned i=0; i < inst->getNumOperands(); ++i) {
     //get machine operand
     const MachineOperand &mOp = inst->getOperand(i);

     if(I->second != 0) {
       if(mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isUse()) {

         //Check to see where this operand is defined if this instruction is from max stage
         if(I->second == schedule.getMaxStage()) {
           DEBUG(std::cerr << "VREG: " << *(mOp.getVRegValue()) << "\n");
         }

         //If its in the value saved, we need to create a temp instruction and use that instead
         if(valuesToSave.count(mOp.getVRegValue())) {

           //Check if we already have a final PHI value for this
           if(!finalPHIValue.count(mOp.getVRegValue())) {
             //Only create phi if the operand def is from a stage before this one
             if(schedule.defPreviousStage(mOp.getVRegValue(), I->second)) {
             TmpInstruction *tmp = new TmpInstruction(mOp.getVRegValue());

             //Get machine code for this instruction
             MachineCodeForInstruction & tempMvec = MachineCodeForInstruction::get(defaultInst);
             tempMvec.addTemp((Value*) tmp);

             //Update the operand in the cloned instruction
             instClone->getOperand(i).setValueReg(tmp);

             //save this as our final phi
             finalPHIValue[mOp.getVRegValue()] = tmp;
             newValLocation[tmp] = machineBB;
             }
           }
           else {
             //Use the previous final phi value
             instClone->getOperand(i).setValueReg(finalPHIValue[mOp.getVRegValue()]);
           }
         }
       }
     }
     if(I->second != schedule.getMaxStage()) {
       if(mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isDef()) {
         if(valuesToSave.count(mOp.getVRegValue())) {

           TmpInstruction *tmp = new TmpInstruction(mOp.getVRegValue());

           //Get machine code for this instruction
           MachineCodeForInstruction & tempVec = MachineCodeForInstruction::get(defaultInst);
           tempVec.addTemp((Value*) tmp);

           //Create new machine instr and put in MBB
           MachineInstr *saveValue;
           if(mOp.getVRegValue()->getType() == Type::FloatTy)
             saveValue = BuildMI(machineBB, V9::FMOVS, 3).addReg(mOp.getVRegValue()).addRegDef(tmp);
           else if(mOp.getVRegValue()->getType() == Type::DoubleTy)
             saveValue = BuildMI(machineBB, V9::FMOVD, 3).addReg(mOp.getVRegValue()).addRegDef(tmp);
           else
             saveValue = BuildMI(machineBB, V9::ORr, 3).addReg(mOp.getVRegValue()).addImm(0).addRegDef(tmp);


           //Save for future cleanup
           kernelValue[mOp.getVRegValue()] = tmp;
           newValLocation[tmp] = machineBB;
           kernelPHIs[mOp.getVRegValue()][schedule.getMaxStage()-1] = tmp;
         }
       }
     }
   }

 }

 //Add branches
 for(std::vector<MachineInstr*>::iterator I = branches.begin(), E = branches.end(); I != E; ++I) {
   machineBB->push_back(*I);
   BuildMI(machineBB, V9::NOP, 0);
 }


  DEBUG(std::cerr << "KERNEL before PHIs\n");
  DEBUG(machineBB->print(std::cerr));


 //Loop over each value we need to generate phis for
 for(std::map<Value*, std::map<int, Value*> >::iterator V = newValues.begin(),
       E = newValues.end(); V != E; ++V) {


   DEBUG(std::cerr << "Writing phi for" << *(V->first));
   DEBUG(std::cerr << "\nMap of Value* for this phi\n");
   DEBUG(for(std::map<int, Value*>::iterator I = V->second.begin(),
               IE = V->second.end(); I != IE; ++I) {
     std::cerr << "Stage: " << I->first;
     std::cerr << " Value: " << *(I->second) << "\n";
   });

   //If we only have one current iteration live, its safe to set lastPhi = to kernel value
   if(V->second.size() == 1) {
     assert(kernelValue[V->first] != 0 && "Kernel value* must exist to create phi");
     MachineInstr *saveValue = BuildMI(*machineBB, machineBB->begin(),V9::PHI, 3).addReg(V->second.begin()->second).addReg(kernelValue[V->first]).addRegDef(finalPHIValue[V->first]);
     DEBUG(std::cerr << "Resulting PHI (one live): " << *saveValue << "\n");
     kernelPHIs[V->first][V->second.begin()->first] = kernelValue[V->first];
     DEBUG(std::cerr << "Put kernel phi in at stage: " << schedule.getMaxStage()-1 << " (map stage = " << V->second.begin()->first << ")\n");
    }
   else {

     //Keep track of last phi created.
     Instruction *lastPhi = 0;

     unsigned count = 1;
     //Loop over the the map backwards to generate phis
     for(std::map<int, Value*>::reverse_iterator I = V->second.rbegin(), IE = V->second.rend();
         I != IE; ++I) {

       if(count < (V->second).size()) {
         if(lastPhi == 0) {
           lastPhi = new TmpInstruction(I->second);

           //Get machine code for this instruction
           MachineCodeForInstruction & tempMvec = MachineCodeForInstruction::get(defaultInst);
           tempMvec.addTemp((Value*) lastPhi);

           MachineInstr *saveValue = BuildMI(*machineBB, machineBB->begin(), V9::PHI, 3).addReg(kernelValue[V->first]).addReg(I->second).addRegDef(lastPhi);
           DEBUG(std::cerr << "Resulting PHI: " << *saveValue << "\n");
           newValLocation[lastPhi] = machineBB;
         }
         else {
           Instruction *tmp = new TmpInstruction(I->second);

           //Get machine code for this instruction
           MachineCodeForInstruction & tempMvec = MachineCodeForInstruction::get(defaultInst);
           tempMvec.addTemp((Value*) tmp);


           MachineInstr *saveValue = BuildMI(*machineBB, machineBB->begin(), V9::PHI, 3).addReg(lastPhi).addReg(I->second).addRegDef(tmp);
           DEBUG(std::cerr << "Resulting PHI: " << *saveValue << "\n");
           lastPhi = tmp;
           kernelPHIs[V->first][I->first] = lastPhi;
           newValLocation[lastPhi] = machineBB;
         }
       }
       //Final phi value
       else {
         //The resulting value must be the Value* we created earlier
         assert(lastPhi != 0 && "Last phi is NULL!\n");
         MachineInstr *saveValue = BuildMI(*machineBB, machineBB->begin(), V9::PHI, 3).addReg(lastPhi).addReg(I->second).addRegDef(finalPHIValue[V->first]);
         DEBUG(std::cerr << "Resulting PHI: " << *saveValue << "\n");
         kernelPHIs[V->first][I->first] = finalPHIValue[V->first];
       }

       ++count;
     }

   }
 }

  DEBUG(std::cerr << "KERNEL after PHIs\n");
  DEBUG(machineBB->print(std::cerr));
}


void ModuloSchedulingPass::removePHIs(const MachineBasicBlock *origBB, std::vector<MachineBasicBlock *> &prologues, std::vector<MachineBasicBlock *> &epilogues, MachineBasicBlock *kernelBB, std::map<Value*, MachineBasicBlock*> &newValLocation) {

  //Worklist to delete things
  std::vector<std::pair<MachineBasicBlock*, MachineBasicBlock::iterator> > worklist;

  //Worklist of TmpInstructions that need to be added to a MCFI
  std::vector<Instruction*> addToMCFI;

  //Worklist to add OR instructions to end of kernel so not to invalidate the iterator
  //std::vector<std::pair<Instruction*, Value*> > newORs;

  const TargetInstrInfo *TMI = target.getInstrInfo();

  //Start with the kernel and for each phi insert a copy for the phi def and for each arg
  for(MachineBasicBlock::iterator I = kernelBB->begin(), E = kernelBB->end(); I != E; ++I) {

    DEBUG(std::cerr << "Looking at Instr: " << *I << "\n");
    //Get op code and check if its a phi
    if(I->getOpcode() == V9::PHI) {

      DEBUG(std::cerr << "Replacing PHI: " << *I << "\n");
      Instruction *tmp = 0;

      for(unsigned i = 0; i < I->getNumOperands(); ++i) {
        //Get Operand
        const MachineOperand &mOp = I->getOperand(i);
        assert(mOp.getType() == MachineOperand::MO_VirtualRegister && "Should be a Value*\n");

        if(!tmp) {
          tmp = new TmpInstruction(mOp.getVRegValue());
          addToMCFI.push_back(tmp);
        }

        //Now for all our arguments we read, OR to the new TmpInstruction that we created
        if(mOp.isUse()) {
          DEBUG(std::cerr << "Use: " << mOp << "\n");
          //Place a copy at the end of its BB but before the branches
          assert(newValLocation.count(mOp.getVRegValue()) && "We must know where this value is located\n");
          //Reverse iterate to find the branches, we can safely assume no instructions have been
          //put in the nop positions
          for(MachineBasicBlock::iterator inst = --(newValLocation[mOp.getVRegValue()])->end(), endBB = (newValLocation[mOp.getVRegValue()])->begin(); inst != endBB; --inst) {
            MachineOpCode opc = inst->getOpcode();
            if(TMI->isBranch(opc) || TMI->isNop(opc))
              continue;
            else {
              if(mOp.getVRegValue()->getType() == Type::FloatTy)
                BuildMI(*(newValLocation[mOp.getVRegValue()]), ++inst, V9::FMOVS, 3).addReg(mOp.getVRegValue()).addRegDef(tmp);
              else if(mOp.getVRegValue()->getType() == Type::DoubleTy)
                BuildMI(*(newValLocation[mOp.getVRegValue()]), ++inst, V9::FMOVD, 3).addReg(mOp.getVRegValue()).addRegDef(tmp);
              else
                BuildMI(*(newValLocation[mOp.getVRegValue()]), ++inst, V9::ORr, 3).addReg(mOp.getVRegValue()).addImm(0).addRegDef(tmp);

              break;
            }

          }

        }
        else {
          //Remove the phi and replace it with an OR
          DEBUG(std::cerr << "Def: " << mOp << "\n");
          //newORs.push_back(std::make_pair(tmp, mOp.getVRegValue()));
          if(tmp->getType() == Type::FloatTy)
            BuildMI(*kernelBB, I, V9::FMOVS, 3).addReg(tmp).addRegDef(mOp.getVRegValue());
          else if(tmp->getType() == Type::DoubleTy)
            BuildMI(*kernelBB, I, V9::FMOVD, 3).addReg(tmp).addRegDef(mOp.getVRegValue());
          else
            BuildMI(*kernelBB, I, V9::ORr, 3).addReg(tmp).addImm(0).addRegDef(mOp.getVRegValue());


          worklist.push_back(std::make_pair(kernelBB, I));
        }

      }

    }


  }

  //Add TmpInstructions to some MCFI
  if(addToMCFI.size() > 0) {
    MachineCodeForInstruction & tempMvec = MachineCodeForInstruction::get(defaultInst);
    for(unsigned x = 0; x < addToMCFI.size(); ++x) {
      tempMvec.addTemp(addToMCFI[x]);
    }
    addToMCFI.clear();
  }


  //Remove phis from epilogue
  for(std::vector<MachineBasicBlock*>::iterator MB = epilogues.begin(), ME = epilogues.end(); MB != ME; ++MB) {
    for(MachineBasicBlock::iterator I = (*MB)->begin(), E = (*MB)->end(); I != E; ++I) {

      DEBUG(std::cerr << "Looking at Instr: " << *I << "\n");
      //Get op code and check if its a phi
      if(I->getOpcode() == V9::PHI) {
        Instruction *tmp = 0;

        for(unsigned i = 0; i < I->getNumOperands(); ++i) {
          //Get Operand
          const MachineOperand &mOp = I->getOperand(i);
          assert(mOp.getType() == MachineOperand::MO_VirtualRegister && "Should be a Value*\n");

          if(!tmp) {
            tmp = new TmpInstruction(mOp.getVRegValue());
            addToMCFI.push_back(tmp);
          }

          //Now for all our arguments we read, OR to the new TmpInstruction that we created
          if(mOp.isUse()) {
            DEBUG(std::cerr << "Use: " << mOp << "\n");
            //Place a copy at the end of its BB but before the branches
            assert(newValLocation.count(mOp.getVRegValue()) && "We must know where this value is located\n");
            //Reverse iterate to find the branches, we can safely assume no instructions have been
            //put in the nop positions
            for(MachineBasicBlock::iterator inst = --(newValLocation[mOp.getVRegValue()])->end(), endBB = (newValLocation[mOp.getVRegValue()])->begin(); inst != endBB; --inst) {
              MachineOpCode opc = inst->getOpcode();
              if(TMI->isBranch(opc) || TMI->isNop(opc))
                continue;
              else {
                if(mOp.getVRegValue()->getType() == Type::FloatTy)
                  BuildMI(*(newValLocation[mOp.getVRegValue()]), ++inst, V9::FMOVS, 3).addReg(mOp.getVRegValue()).addRegDef(tmp);
                else if(mOp.getVRegValue()->getType() == Type::DoubleTy)
                  BuildMI(*(newValLocation[mOp.getVRegValue()]), ++inst, V9::FMOVD, 3).addReg(mOp.getVRegValue()).addRegDef(tmp);
                else
                  BuildMI(*(newValLocation[mOp.getVRegValue()]), ++inst, V9::ORr, 3).addReg(mOp.getVRegValue()).addImm(0).addRegDef(tmp);


                break;
              }

            }

          }
          else {
            //Remove the phi and replace it with an OR
            DEBUG(std::cerr << "Def: " << mOp << "\n");
             if(tmp->getType() == Type::FloatTy)
               BuildMI(**MB, I, V9::FMOVS, 3).addReg(tmp).addRegDef(mOp.getVRegValue());
             else if(tmp->getType() == Type::DoubleTy)
               BuildMI(**MB, I, V9::FMOVD, 3).addReg(tmp).addRegDef(mOp.getVRegValue());
             else
               BuildMI(**MB, I, V9::ORr, 3).addReg(tmp).addImm(0).addRegDef(mOp.getVRegValue());

            worklist.push_back(std::make_pair(*MB,I));
          }

        }
      }


    }
  }


  if(addToMCFI.size() > 0) {
    MachineCodeForInstruction & tempMvec = MachineCodeForInstruction::get(defaultInst);
    for(unsigned x = 0; x < addToMCFI.size(); ++x) {
      tempMvec.addTemp(addToMCFI[x]);
    }
    addToMCFI.clear();
  }

    //Delete the phis
  for(std::vector<std::pair<MachineBasicBlock*, MachineBasicBlock::iterator> >::iterator I =  worklist.begin(), E = worklist.end(); I != E; ++I) {

    DEBUG(std::cerr << "Deleting PHI " << *I->second << "\n");
    I->first->erase(I->second);

  }


  assert((addToMCFI.size() == 0) && "We should have added all TmpInstructions to some MachineCodeForInstruction");
}


void ModuloSchedulingPass::reconstructLoop(MachineBasicBlock *BB) {

  TIME_REGION(X, "reconstructLoop");


  DEBUG(std::cerr << "Reconstructing Loop\n");

  //First find the value *'s that we need to "save"
  std::map<const Value*, std::pair<const MachineInstr*, int> > valuesToSave;

  //Keep track of instructions we have already seen and their stage because
  //we don't want to "save" values if they are used in the kernel immediately
  std::map<const MachineInstr*, int> lastInstrs;
  std::map<const Value*, int> phiUses;

  //Loop over kernel and only look at instructions from a stage > 0
  //Look at its operands and save values *'s that are read
  for(MSSchedule::kernel_iterator I = schedule.kernel_begin(), E = schedule.kernel_end(); I != E; ++I) {

    if(I->second !=0) {
      //For this instruction, get the Value*'s that it reads and put them into the set.
      //Assert if there is an operand of another type that we need to save
      const MachineInstr *inst = I->first;
      lastInstrs[inst] = I->second;

      for(unsigned i=0; i < inst->getNumOperands(); ++i) {
        //get machine operand
        const MachineOperand &mOp = inst->getOperand(i);

        if(mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isUse()) {
          //find the value in the map
          if (const Value* srcI = mOp.getVRegValue()) {

            if(isa<Constant>(srcI) || isa<Argument>(srcI))
              continue;

            //Before we declare this Value* one that we should save
            //make sure its def is not of the same stage as this instruction
            //because it will be consumed before its used
            Instruction *defInst = (Instruction*) srcI;

            //Should we save this value?
            bool save = true;

            //Continue if not in the def map, loop invariant code does not need to be saved
            if(!defMap.count(srcI))
              continue;

            MachineInstr *defInstr = defMap[srcI];


            if(lastInstrs.count(defInstr)) {
              if(lastInstrs[defInstr] == I->second) {
                save = false;

              }
            }

            if(save) {
              assert(!phiUses.count(srcI) && "Did not expect to see phi use twice");
              if(isa<PHINode>(srcI))
                phiUses[srcI] = I->second;

              valuesToSave[srcI] = std::make_pair(I->first, i);

            }
          }
        }
        else if(mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isDef()) {
          if (const Value* destI = mOp.getVRegValue()) {
            if(!isa<PHINode>(destI))
              continue;
            if(phiUses.count(destI)) {
              if(phiUses[destI] == I->second) {
                //remove from save list
                valuesToSave.erase(destI);
              }
            }
          }
        }

        if(mOp.getType() != MachineOperand::MO_VirtualRegister && mOp.isUse()) {
          assert("Our assumption is wrong. We have another type of register that needs to be saved\n");
        }
      }
    }
  }

  //The new loop will consist of one or more prologues, the kernel, and one or more epilogues.

  //Map to keep track of old to new values
  std::map<Value*, std::map<int, Value*> > newValues;

  //Map to keep track of old to new values in kernel
  std::map<Value*, std::map<int, Value*> > kernelPHIs;

  //Another map to keep track of what machine basic blocks these new value*s are in since
  //they have no llvm instruction equivalent
  std::map<Value*, MachineBasicBlock*> newValLocation;

  std::vector<MachineBasicBlock*> prologues;
  std::vector<BasicBlock*> llvm_prologues;


  //Write prologue
  if(schedule.getMaxStage() != 0)
    writePrologues(prologues, BB, llvm_prologues, valuesToSave, newValues, newValLocation);

  //Print out epilogues and prologue
  DEBUG(for(std::vector<MachineBasicBlock*>::iterator I = prologues.begin(), E = prologues.end();
      I != E; ++I) {
    std::cerr << "PROLOGUE\n";
    (*I)->print(std::cerr);
  });

  BasicBlock *llvmKernelBB = new BasicBlock("Kernel", (Function*) (BB->getBasicBlock()->getParent()));
  MachineBasicBlock *machineKernelBB = new MachineBasicBlock(llvmKernelBB);

  MachineFunction *F = (((MachineBasicBlock*)BB)->getParent());
  MachineFunction::BasicBlockListType &BL = F->getBasicBlockList();
  MachineFunction::BasicBlockListType::iterator BLI = BB;
  assert(BLI != BL.end() && "Must find original BB in machine function\n");
  BL.insert(BLI,machineKernelBB);

  //(((MachineBasicBlock*)BB)->getParent())->getBasicBlockList().push_back(machineKernelBB);
  writeKernel(llvmKernelBB, machineKernelBB, valuesToSave, newValues, newValLocation, kernelPHIs);


  std::vector<MachineBasicBlock*> epilogues;
  std::vector<BasicBlock*> llvm_epilogues;

  //Write epilogues
  if(schedule.getMaxStage() != 0)
    writeEpilogues(epilogues, BB, llvm_epilogues, valuesToSave, newValues, newValLocation, kernelPHIs);


  //Fix our branches
  fixBranches(prologues, llvm_prologues, machineKernelBB, llvmKernelBB, epilogues, llvm_epilogues, BB);

  //Remove phis
  removePHIs(BB, prologues, epilogues, machineKernelBB, newValLocation);

  //Print out epilogues and prologue
  DEBUG(for(std::vector<MachineBasicBlock*>::iterator I = prologues.begin(), E = prologues.end();
      I != E; ++I) {
    std::cerr << "PROLOGUE\n";
    (*I)->print(std::cerr);
  });

  DEBUG(std::cerr << "KERNEL\n");
  DEBUG(machineKernelBB->print(std::cerr));

  DEBUG(for(std::vector<MachineBasicBlock*>::iterator I = epilogues.begin(), E = epilogues.end();
      I != E; ++I) {
    std::cerr << "EPILOGUE\n";
    (*I)->print(std::cerr);
  });


  DEBUG(std::cerr << "New Machine Function" << "\n");
  DEBUG(std::cerr << BB->getParent() << "\n");


}

void ModuloSchedulingPass::fixBranches(std::vector<MachineBasicBlock *> &prologues, std::vector<BasicBlock*> &llvm_prologues, MachineBasicBlock *machineKernelBB, BasicBlock *llvmKernelBB, std::vector<MachineBasicBlock *> &epilogues, std::vector<BasicBlock*> &llvm_epilogues, MachineBasicBlock *BB) {

  const TargetInstrInfo *TMI = target.getInstrInfo();

  if(schedule.getMaxStage() != 0) {
    //Fix prologue branches
    for(unsigned I = 0; I <  prologues.size(); ++I) {

      //Find terminator since getFirstTerminator does not work!
      for(MachineBasicBlock::reverse_iterator mInst = prologues[I]->rbegin(), mInstEnd = prologues[I]->rend(); mInst != mInstEnd; ++mInst) {
        MachineOpCode OC = mInst->getOpcode();
        //If its a branch update its branchto
        if(TMI->isBranch(OC)) {
          for(unsigned opNum = 0; opNum < mInst->getNumOperands(); ++opNum) {
            MachineOperand &mOp = mInst->getOperand(opNum);
            if (mOp.getType() == MachineOperand::MO_PCRelativeDisp) {
              //Check if we are branching to the kernel, if not branch to epilogue
              if(mOp.getVRegValue() == BB->getBasicBlock()) {
                if(I == prologues.size()-1)
                  mOp.setValueReg(llvmKernelBB);
                else
                  mOp.setValueReg(llvm_prologues[I+1]);
              }
              else {
                mOp.setValueReg(llvm_epilogues[(llvm_epilogues.size()-1-I)]);
              }
            }
          }

          DEBUG(std::cerr << "New Prologue Branch: " << *mInst << "\n");
        }
      }


      //Update llvm basic block with our new branch instr
      DEBUG(std::cerr << BB->getBasicBlock()->getTerminator() << "\n");
      const BranchInst *branchVal = dyn_cast<BranchInst>(BB->getBasicBlock()->getTerminator());

      if(I == prologues.size()-1) {
        TerminatorInst *newBranch = new BranchInst(llvmKernelBB,
                                                   llvm_epilogues[(llvm_epilogues.size()-1-I)],
                                                   branchVal->getCondition(),
                                                   llvm_prologues[I]);
      }
      else
        TerminatorInst *newBranch = new BranchInst(llvm_prologues[I+1],
                                                   llvm_epilogues[(llvm_epilogues.size()-1-I)],
                                                   branchVal->getCondition(),
                                                   llvm_prologues[I]);

    }
  }

  Value *origBranchExit = 0;

  //Fix up kernel machine branches
  for(MachineBasicBlock::reverse_iterator mInst = machineKernelBB->rbegin(), mInstEnd = machineKernelBB->rend(); mInst != mInstEnd; ++mInst) {
    MachineOpCode OC = mInst->getOpcode();
    if(TMI->isBranch(OC)) {
      for(unsigned opNum = 0; opNum < mInst->getNumOperands(); ++opNum) {
        MachineOperand &mOp = mInst->getOperand(opNum);

        if(mOp.getType() == MachineOperand::MO_PCRelativeDisp) {
          if(mOp.getVRegValue() == BB->getBasicBlock())
            mOp.setValueReg(llvmKernelBB);
          else
            if(llvm_epilogues.size() > 0) {
              assert(origBranchExit == 0 && "There should only be one branch out of the loop");

              origBranchExit = mOp.getVRegValue();
              mOp.setValueReg(llvm_epilogues[0]);
            }
            else
              origBranchExit = mOp.getVRegValue();
        }
      }
    }
  }

  //Update kernelLLVM branches
  const BranchInst *branchVal = dyn_cast<BranchInst>(BB->getBasicBlock()->getTerminator());

  assert(origBranchExit != 0 && "We must have the original bb the kernel exits to!");

  if(epilogues.size() > 0) {
    TerminatorInst *newBranch = new BranchInst(llvmKernelBB,
                                               llvm_epilogues[0],
                                               branchVal->getCondition(),
                                               llvmKernelBB);
  }
  else {
    BasicBlock *origBBExit = dyn_cast<BasicBlock>(origBranchExit);
    assert(origBBExit !=0 && "Original exit basic block must be set");
    TerminatorInst *newBranch = new BranchInst(llvmKernelBB,
                                               origBBExit,
                                               branchVal->getCondition(),
                                               llvmKernelBB);
  }

  if(schedule.getMaxStage() != 0) {
   //Lastly add unconditional branches for the epilogues
   for(unsigned I = 0; I <  epilogues.size(); ++I) {

    //Now since we don't have fall throughs, add a unconditional branch to the next prologue
     if(I != epilogues.size()-1) {
       BuildMI(epilogues[I], V9::BA, 1).addPCDisp(llvm_epilogues[I+1]);
       //Add unconditional branch to end of epilogue
       TerminatorInst *newBranch = new BranchInst(llvm_epilogues[I+1],
                                                  llvm_epilogues[I]);

     }
     else {
       BuildMI(epilogues[I], V9::BA, 1).addPCDisp(origBranchExit);


       //Update last epilogue exit branch
       BranchInst *branchVal = (BranchInst*) dyn_cast<BranchInst>(BB->getBasicBlock()->getTerminator());
       //Find where we are supposed to branch to
       BasicBlock *nextBlock = 0;
       for(unsigned j=0; j <branchVal->getNumSuccessors(); ++j) {
         if(branchVal->getSuccessor(j) != BB->getBasicBlock())
           nextBlock = branchVal->getSuccessor(j);
       }

       assert((nextBlock != 0) && "Next block should not be null!");
       TerminatorInst *newBranch = new BranchInst(nextBlock, llvm_epilogues[I]);
     }
     //Add one more nop!
     BuildMI(epilogues[I], V9::NOP, 0);

   }
  }

   //FIX UP Machine BB entry!!
   //We are looking at the predecesor of our loop basic block and we want to change its ba instruction


   //Find all llvm basic blocks that branch to the loop entry and change to our first prologue.
   const BasicBlock *llvmBB = BB->getBasicBlock();

   std::vector<const BasicBlock*>Preds (pred_begin(llvmBB), pred_end(llvmBB));

   //for(pred_const_iterator P = pred_begin(llvmBB), PE = pred_end(llvmBB); P != PE; ++PE) {
   for(std::vector<const BasicBlock*>::iterator P = Preds.begin(), PE = Preds.end(); P != PE; ++P) {
     if(*P == llvmBB)
       continue;
     else {
       DEBUG(std::cerr << "Found our entry BB\n");
       //Get the Terminator instruction for this basic block and print it out
       DEBUG(std::cerr << *((*P)->getTerminator()) << "\n");
       //Update the terminator
       TerminatorInst *term = ((BasicBlock*)*P)->getTerminator();
       for(unsigned i=0; i < term->getNumSuccessors(); ++i) {
         if(term->getSuccessor(i) == llvmBB) {
           DEBUG(std::cerr << "Replacing successor bb\n");
           if(llvm_prologues.size() > 0) {
             term->setSuccessor(i, llvm_prologues[0]);
             //Also update its corresponding machine instruction
             MachineCodeForInstruction & tempMvec =
               MachineCodeForInstruction::get(term);
             for (unsigned j = 0; j < tempMvec.size(); j++) {
               MachineInstr *temp = tempMvec[j];
               MachineOpCode opc = temp->getOpcode();
               if(TMI->isBranch(opc)) {
                 DEBUG(std::cerr << *temp << "\n");
                 //Update branch
                 for(unsigned opNum = 0; opNum < temp->getNumOperands(); ++opNum) {
                   MachineOperand &mOp = temp->getOperand(opNum);
                   if (mOp.getType() == MachineOperand::MO_PCRelativeDisp) {
                     if(mOp.getVRegValue() == llvmBB)
                       mOp.setValueReg(llvm_prologues[0]);
                   }
                 }
               }
             }
           }
           else {
             term->setSuccessor(i, llvmKernelBB);
           //Also update its corresponding machine instruction
             MachineCodeForInstruction & tempMvec =
               MachineCodeForInstruction::get(term);
             for (unsigned j = 0; j < tempMvec.size(); j++) {
               MachineInstr *temp = tempMvec[j];
               MachineOpCode opc = temp->getOpcode();
               if(TMI->isBranch(opc)) {
                 DEBUG(std::cerr << *temp << "\n");
                 //Update branch
                 for(unsigned opNum = 0; opNum < temp->getNumOperands(); ++opNum) {
                   MachineOperand &mOp = temp->getOperand(opNum);
                   if (mOp.getType() == MachineOperand::MO_PCRelativeDisp) {
                     if(mOp.getVRegValue() == llvmBB)
                       mOp.setValueReg(llvmKernelBB);
                   }
                 }
               }
             }
           }
         }
       }
       break;
     }
   }


  //BB->getParent()->getBasicBlockList().erase(BB);

}