llvm-6502/lib/CodeGen/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.
//
//===----------------------------------------------------------------------===//
//
// 
//
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "ModuloSched"

#include "ModuloScheduling.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/CFG.h"
#include "llvm/Target/TargetSchedInfo.h"
#include "Support/Debug.h"
#include "Support/GraphWriter.h"
#include "Support/StringExtras.h"
#include <vector>
#include <utility>
#include <iostream>
#include <fstream>
#include <sstream>


using namespace llvm;

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

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";
};

namespace llvm {

  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;
    }
    
    
    
  };
}

/// ModuloScheduling::runOnFunction - main transformation entry point
bool ModuloSchedulingPass::runOnFunction(Function &F) {
  bool Changed = false;

  DEBUG(std::cerr << "Creating ModuloSchedGraph for each BasicBlock in" + F.getName() + "\n");
  
  //Get MachineFunction
  MachineFunction &MF = MachineFunction::get(&F);

  //Iterate over BasicBlocks and do ModuloScheduling if they are valid
  for (MachineFunction::const_iterator BI = MF.begin(); BI != MF.end(); ++BI) {
    if(MachineBBisValid(BI)) {
      MSchedGraph *MSG = new MSchedGraph(BI, target);
    
      //Write Graph out to file
      DEBUG(WriteGraphToFile(std::cerr, F.getName(), MSG));

      //Print out BB for debugging
      DEBUG(BI->print(std::cerr));

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

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

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

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

      //Dump node properties if in debug mode
      for(std::map<MSchedGraphNode*, MSNodeAttributes>::iterator I =  nodeToAttributesMap.begin(), E = nodeToAttributesMap.end(); I !=E; ++I) {
	DEBUG(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
      for(std::vector<std::vector<MSchedGraphNode*> >::iterator I = partialOrder.begin(), E = partialOrder.end(); I !=E; ++I) {
	DEBUG(std::cerr << "Start set in PO\n");
	for(std::vector<MSchedGraphNode*>::iterator J = I->begin(), JE = I->end(); J != JE; ++J)
	  DEBUG(std::cerr << "PO:" << **J << "\n");
      }

      orderNodes();

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


      //Finally schedule nodes
      computeSchedule();

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


      nodeToAttributesMap.clear();
      partialOrder.clear();
      recurrenceList.clear();
      FinalNodeOrder.clear();
      schedule.clear();
      }
    
  }


  return Changed;
}


bool ModuloSchedulingPass::MachineBBisValid(const MachineBasicBlock *BI) {

  //Valid basic blocks must be loops and can not have if/else statements or calls.
  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) {
    DEBUG(std::cerr << "Basic Block is not a loop\n");
    return false;
  }
  else 
    DEBUG(std::cerr << "Basic Block is a loop\n");
  
  //Get Target machine instruction info
  /*const TargetInstrInfo& TMI = targ.getInstrInfo();
    
  //Check each instruction and look for calls or if/else statements
  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();
  if(TMI.isControlFlow(OC) && (count+1 < BI->size()))
  return false;
  count++;
  }*/
  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) {
  
  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.find(resources[i][j]) == resourceUsageCount.end()) {
	  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;
    if( resourceNum <= issueSlots)
      finalUsageCount = ceil(1.0 * usageCount / resourceNum);
    else
      finalUsageCount = ceil(1.0 * usageCount / issueSlots);
    
    
    DEBUG(std::cerr << "Resource ID: " << RB->first << " (usage=" << usageCount << ", resourceNum=X" << ", issueSlots=" << issueSlots << ", finalUsage=" << finalUsageCount << ")\n");

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

  }

  DEBUG(std::cerr << "Final Resource MII: " << ResMII << "\n");
  
  return ResMII;

}

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();
  }

  int RecMII = 0;
  
  for(std::set<std::pair<int, std::vector<MSchedGraphNode*> > >::iterator I = recurrenceList.begin(), E=recurrenceList.end(); I !=E; ++I) {
    std::cerr << "Recurrence: \n";
    for(std::vector<MSchedGraphNode*>::const_iterator N = I->second.begin(), NE = I->second.end(); N != NE; ++N) {
      std::cerr << **N << "\n";
    }
    RecMII = std::max(RecMII, I->first);
    std::cerr << "End Recurrence with RecMII: " << I->first << "\n";
    }
  DEBUG(std::cerr << "RecMII: " << RecMII << "\n");
  
  return MII;
}

void ModuloSchedulingPass::calculateNodeAttributes(MSchedGraph *graph, int MII) {

  //Loop over the nodes and add them to the map
  for(MSchedGraph::iterator I = graph->begin(), E = graph->end(); I != E; ++I) {
    //Assert if its already in the map
    assert(nodeToAttributesMap.find(I->second) == nodeToAttributesMap.end() && "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);
  }


}

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)));
  
  return findEdge;
}

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(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));
  }
  
}

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

  if(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;
    MSchedGraphNode *destBackEdge;
    


    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();
   

    //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;
  }

  for(MSchedGraphNode::succ_iterator I = node->succ_begin(), E = node->succ_end(); I != E; ++I) {
    visitedNodes.push_back(node);
    findAllReccurrences(*I, visitedNodes, II);
    visitedNodes.pop_back();
  }
}





void ModuloSchedulingPass::computePartialOrder() {
  
  
  //Loop over all recurrences and add to our partial order
  //be sure to remove nodes that are already in the partial order in
  //a different recurrence and don't add empty recurrences.
  for(std::set<std::pair<int, std::vector<MSchedGraphNode*> > >::reverse_iterator I = recurrenceList.rbegin(), E=recurrenceList.rend(); I !=E; ++I) {
    
    //Add nodes that connect this recurrence to the previous recurrence
    
    //If this is the first recurrence in the partial order, add all predecessors
    for(std::vector<MSchedGraphNode*>::const_iterator N = I->second.begin(), NE = I->second.end(); N != NE; ++N) {

    }


    std::vector<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::vector<MSchedGraphNode*> >::iterator PO = partialOrder.begin(), PE = partialOrder.end(); PO != PE; ++PO) {
	if(find(PO->begin(), PO->end(), *N) != PO->end())
	  found = true;
      }
      if(!found) {
	new_recurrence.push_back(*N);
	 
	if(partialOrder.size() == 0)
	  //For each predecessors, add it to this recurrence ONLY if it is not already in it
	  for(MSchedGraphNode::pred_iterator P = (*N)->pred_begin(), 
		PE = (*N)->pred_end(); P != PE; ++P) {
	    
	    //Check if we are supposed to ignore this edge or not
	    if(!ignoreEdge(*P, *N))
	      //Check if already in this recurrence
	      if(find(I->second.begin(), I->second.end(), *P) == I->second.end()) {
		//Also need to check if in partial order
		bool predFound = false;
		for(std::vector<std::vector<MSchedGraphNode*> >::iterator PO = partialOrder.begin(), PEND = partialOrder.end(); PO != PEND; ++PO) {
		  if(find(PO->begin(), PO->end(), *P) != PO->end())
		    predFound = true;
		}
		
		if(!predFound)
		  if(find(new_recurrence.begin(), new_recurrence.end(), *P) == new_recurrence.end())
		     new_recurrence.push_back(*P);
		
	      }
	  }
      }
    }

        
    if(new_recurrence.size() > 0)
      partialOrder.push_back(new_recurrence);
  }
  
  //Add any nodes that are not already in the partial order
  std::vector<MSchedGraphNode*> lastNodes;
  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::vector<MSchedGraphNode*> >::iterator PO = partialOrder.begin(), PE = partialOrder.end(); PO != PE; ++PO) {
      if(find(PO->begin(), PO->end(), I->first) != PO->end())
	found = true;
    }
    if(!found)
      lastNodes.push_back(I->first);
  }

  if(lastNodes.size() > 0)
    partialOrder.push_back(lastNodes);
  
}


void ModuloSchedulingPass::predIntersect(std::vector<MSchedGraphNode*> &CurrentSet, std::vector<MSchedGraphNode*> &IntersectResult) {
  
  //Sort CurrentSet so we can use lowerbound
  sort(CurrentSet.begin(), CurrentSet.end());
  
  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(find(CurrentSet.begin(), 
		     CurrentSet.end(), *P) != CurrentSet.end())
	if(find(FinalNodeOrder.begin(), FinalNodeOrder.end(), *P) == FinalNodeOrder.end())
	  IntersectResult.push_back(*P);
    }
  } 
}

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

  //Sort CurrentSet so we can use lowerbound
  sort(CurrentSet.begin(), CurrentSet.end());
  
  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(find(CurrentSet.begin(), 
		     CurrentSet.end(), *P) != CurrentSet.end())
	if(find(FinalNodeOrder.begin(), FinalNodeOrder.end(), *P) == FinalNodeOrder.end())
	  IntersectResult.push_back(*P);
    }
  }
}

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



void ModuloSchedulingPass::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::vector<MSchedGraphNode*> >::iterator CurrentSet = partialOrder.begin(), E= partialOrder.end(); CurrentSet != E; ++CurrentSet) {

    DEBUG(std::cerr << "Processing set in S\n");
    dumpIntersection(*CurrentSet);
    //Result of intersection
    std::vector<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(unsigned j=0; j < CurrentSet->size(); ++j) {
	  //Get node attributes
	  MSNodeAttributes nodeAttr= nodeToAttributesMap.find((*CurrentSet)[j])->second;
	  //assert(nodeAttr != nodeToAttributesMap.end() && "Node not in attributes map!");
	  DEBUG(std::cerr << "CurrentSet index " << j << "has ASAP: " << nodeAttr.ASAP << "\n");
	  if(maxASAP < nodeAttr.ASAP) {
	    maxASAP = nodeAttr.ASAP;
	    node = (*CurrentSet)[j];
	  }
	}
	assert(node != 0 && "In node ordering node should not be null");
	IntersectCurrent.push_back(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[0];
	  	  
	  //Find node in intersection with highest heigh and lowest MOB
	  for(std::vector<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(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(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(find(CurrentSet->begin(), CurrentSet->end(), *P) != CurrentSet->end()) {  
	      if(ignoreEdge(highestHeightNode, *P))
		continue;
	      //If not already in Intersect, add
	      if(find(IntersectCurrent.begin(), IntersectCurrent.end(), *P) == IntersectCurrent.end())
		IntersectCurrent.push_back(*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[0];
	  
	  for(std::vector<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(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(find(IntersectCurrent.begin(), 
				      IntersectCurrent.end(),highestDepthNode));
	  

	  //Intersect heightDepthNode's pred with CurrentSet
	  for(MSchedGraphNode::pred_iterator P = highestDepthNode->pred_begin(), 
		E = highestDepthNode->pred_end(); P != E; ++P) {
	    //if(lower_bound(CurrentSet->begin(), 
	    //	   CurrentSet->end(), *P) != CurrentSet->end()) {
	    if(find(CurrentSet->begin(), CurrentSet->end(), *P) != CurrentSet->end()) {
	    
	      if(ignoreEdge(*P, highestDepthNode))
		continue;
	    
	    //If not already in Intersect, add
	    if(find(IntersectCurrent.begin(), 
		      IntersectCurrent.end(), *P) == IntersectCurrent.end())
		IntersectCurrent.push_back(*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
	
    }
    //End Wrapping while loop
      
  }//End for over all sets of nodes
   
  //Return final Order
  //return FinalNodeOrder;
}

void ModuloSchedulingPass::computeSchedule() {

  bool success = false;
  
  while(!success) {

    //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
      int EarlyStart = -1;
      int LateStart = 99999; //Set to something higher then we would ever expect (FIXME)
      bool hasSucc = false;
      bool hasPred = false;
      
      if(!(*I)->isBranch()) {
	//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)) {
	      if(!ignoreEdge(*schedNode, *I)) {
		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");
		EarlyStart = std::max(EarlyStart, ES_Temp);
		hasPred = true;
	      }
	    }
	    if((*I)->isSuccessor(*schedNode)) {
	      if(!ignoreEdge(*I,*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");
		LateStart = std::min(LateStart, LS_Temp);
		hasSucc = true;
	      }
	    }
	  }
	}
      }
      else {
	//WARNING: HACK! FIXME!!!!
	EarlyStart = II-1;
	LateStart = II-1;
	hasPred = 1;
	hasSucc = 1;
      }
 
      
      DEBUG(std::cerr << "Has Successors: " << hasSucc << ", Has Pred: " << hasPred << "\n");
      DEBUG(std::cerr << "EarlyStart: " << EarlyStart << ", LateStart: " << LateStart << "\n");

      //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;
      
      //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)
	success = scheduleNode(*I, EarlyStart, std::min(LateStart, (EarlyStart + II -1)));
      else
	success = scheduleNode(*I, EarlyStart, EarlyStart + II - 1);
      
      if(!success) {
	++II; 
	schedule.clear();
	break;
      }
     
    }

    DEBUG(std::cerr << "Constructing Kernel\n");
    success = schedule.constructKernel(II);
    if(!success) {
      ++II;
      schedule.clear();
    }
  } 
}


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);
    
    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::saveValue(const MachineInstr *inst, std::set<const Value*> &valuestoSave, std::vector<Value*> *valuesForNode) {
  int numFound = 0;
  Instruction *tmp;

  //For each value* in this inst that is a def, we want to save a copy
  //Target info
  const TargetInstrInfo & mii = target.getInstrInfo();
  for(unsigned i=0; i < inst->getNumOperands(); ++i) {
    //get machine operand
    const MachineOperand &mOp = inst->getOperand(i);
    if(mOp.getType() == MachineOperand::MO_VirtualRegister && mOp.isDef()) {
      //Save copy in tmpInstruction
      numFound++;
      tmp = TmpInstruction(mii.getMachineCodeFor(mOp.getVRegValue()),
                 mOp.getVRegValue());
      valuesForNode->push_back(tmp);
    }
  }

  assert(numFound == 1 && "We should have only found one def to this virtual register!"); 
}*/

void ModuloSchedulingPass::writePrologues(std::vector<MachineBasicBlock *> &prologues, const MachineBasicBlock *origBB, std::vector<BasicBlock*> &llvm_prologues) {
  
  std::map<int, std::set<const MachineInstr*> > inKernel;
  int maxStageCount = 0;

  for(MSSchedule::kernel_iterator I = schedule.kernel_begin(), E = schedule.kernel_end(); I != E; ++I) {
    maxStageCount = std::max(maxStageCount, I->second);
    
    //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
    if(I->second > 0) {
      DEBUG(std::cerr << "Inserting instruction " << *(I->first->getInst()) << " into map at stage " << I->second << "\n");
      inKernel[I->second].insert(I->first->getInst());
    }
  }

  //Now write the prologues
  for(int i = 1; i <= maxStageCount; ++i) {
    BasicBlock *llvmBB = new BasicBlock();
    MachineBasicBlock *machineBB = new MachineBasicBlock(llvmBB);
  
    //Loop over original machine basic block. If we see an instruction from this
    //stage that is NOT in the kernel, then it needs to be added into the prologue
    //We go in order to preserve dependencies
    for(MachineBasicBlock::const_iterator MI = origBB->begin(), ME = origBB->end(); ME != MI; ++MI) {
      if(inKernel[i].count(&*MI)) {
	inKernel[i].erase(&*MI);
        if(inKernel[i].size() <= 0)
          break;
        else
          continue;
      }
      else {
	DEBUG(std::cerr << "Writing instruction to prologue\n");
        machineBB->push_back(MI->clone());
      }
    }

    (((MachineBasicBlock*)origBB)->getParent())->getBasicBlockList().push_back(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<int, std::set<const MachineInstr*> > inKernel;
  int maxStageCount = 0;
  for(MSSchedule::kernel_iterator I = schedule.kernel_begin(), E = schedule.kernel_end(); I != E; ++I) {
    maxStageCount = std::max(maxStageCount, I->second);
    
    //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
    if(I->second > 0) {
      DEBUG(std::cerr << "Inserting instruction " << *(I->first->getInst()) << " into map at stage " << I->second << "\n");
      inKernel[I->second].insert(I->first->getInst());
    }
  }

  //Now write the epilogues
  for(int i = 1; i <= maxStageCount; ++i) {
    BasicBlock *llvmBB = new BasicBlock();
    MachineBasicBlock *machineBB = new MachineBasicBlock(llvmBB);
    
    bool last = false;
    for(MachineBasicBlock::const_iterator MI = origBB->begin(), ME = origBB->end(); ME != MI; ++MI) {
      
      if(!last) {
        if(inKernel[i].count(&*MI)) {
          machineBB->push_back(MI->clone());
          inKernel[i].erase(&*MI);
          if(inKernel[i].size() <= 0)
            last = true;
        }
      }
      
      else
        machineBB->push_back(MI->clone());
     

    }
    (((MachineBasicBlock*)origBB)->getParent())->getBasicBlockList().push_back(machineBB);
    epilogues.push_back(machineBB);
    llvm_epilogues.push_back(llvmBB);
  }
    
}



void ModuloSchedulingPass::reconstructLoop(const MachineBasicBlock *BB) {

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

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

  //Write prologue
  writePrologues(prologues, BB, llvm_prologues);

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


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

  //Write epilogues
  writeEpilogues(epilogues, BB, llvm_epilogues);

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

  //create a vector of epilogues corresponding to each stage
  /*std::vector<MachineBasicBlock*> epilogues;

    //Create kernel
  MachineBasicBlock *kernel = new MachineBasicBlock();

  //keep track of stage count
  int stageCount = 0;
  
  //Target info
  const TargetInstrInfo & mii = target.getInstrInfo();

  //Map for creating MachinePhis
  std::map<MSchedGraphNode *, std::vector<Value*> > nodeAndValueMap; 
  

  //Loop through the kernel and clone instructions that need to be put into the prologue
  for(MSSchedule::kernel_iterator I = schedule.kernel_begin(), E = schedule.kernel_end(); I != E; ++I) {
    //For each pair see if the stage is greater then 0
    //if so, then ALL instructions before this in the original loop, need to be
    //copied into the prologue
    MachineBasicBlock::const_iterator actualInst;


    //ignore branch
    if(I->first->isBranch())
      continue;

    if(I->second > 0) {

      assert(I->second >= stageCount && "Visiting instruction from previous stage count.\n");

      
      //Make a set that has all the Value*'s that we read
      std::set<const Value*> valuesToSave;

      //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->getInst();
      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())
	    valuesToSave.insert(srcI);
	}
	
	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");
	}
      }

      //Check if we skipped a stage count, we need to add that stuff here
      if(I->second - stageCount > 1) {
	int temp = stageCount;
	while(I->second - temp > 1) {
	  for(MachineBasicBlock::const_iterator MI = BB->begin(), ME = BB->end(); ME != MI; ++MI) {
	    //Check that MI is not a branch before adding, we add branches separately
	    if(!mii.isBranch(MI->getOpcode()) && !mii.isNop(MI->getOpcode())) {
	      prologue->push_back(MI->clone());
	      saveValue(&*MI, valuesToSave);
	    }
	  }
	  ++temp;
	}
      }

      if(I->second == stageCount)
	continue;

      stageCount = I->second;
      DEBUG(std::cerr << "Found Instruction from Stage > 0\n");
      //Loop over instructions in original basic block and clone them. Add to the prologue
      for (MachineBasicBlock::const_iterator MI = BB->begin(), e = BB->end(); MI != e; ++MI) {
	if(&*MI == I->first->getInst()) {
	  actualInst = MI;
	  break;
	}
	else {
	  //Check that MI is not a branch before adding, we add branches separately
	  if(!mii.isBranch(MI->getOpcode()) && !mii.isNop(MI->getOpcode()))
	    prologue->push_back(MI->clone());
	}
      }
      
      //Now add in all instructions from this one on to its corresponding epilogue
      MachineBasicBlock *epi = new MachineBasicBlock();
      epilogues.push_back(epi);

      for(MachineBasicBlock::const_iterator MI = actualInst, ME = BB->end(); ME != MI; ++MI) {
	//Check that MI is not a branch before adding, we add branches separately
	if(!mii.isBranch(MI->getOpcode()) && !mii.isNop(MI->getOpcode()))
	  epi->push_back(MI->clone());
      }
    }
  }

  //Create kernel
   for(MSSchedule::kernel_iterator I = schedule.kernel_begin(), 
	 E = schedule.kernel_end(); I != E; ++I) {
     kernel->push_back(I->first->getInst()->clone());
     
     }

  //Debug stuff
  ((MachineBasicBlock*)BB)->getParent()->getBasicBlockList().push_back(prologue);
  std::cerr << "PROLOGUE:\n";
  prologue->print(std::cerr);

  ((MachineBasicBlock*)BB)->getParent()->getBasicBlockList().push_back(kernel);
  std::cerr << "KERNEL: \n";
  kernel->print(std::cerr);

  for(std::vector<MachineBasicBlock*>::iterator MBB = epilogues.begin(), ME = epilogues.end();
      MBB != ME; ++MBB) {
    std::cerr << "EPILOGUE:\n";
    ((MachineBasicBlock*)BB)->getParent()->getBasicBlockList().push_back(*MBB);
    (*MBB)->print(std::cerr);
    }*/



}