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diff --git a/lib/Analysis/SparsePropagation.cpp b/lib/Analysis/SparsePropagation.cpp
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+//===- SparsePropagation.cpp - Sparse Conditional Property Propagation ----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements an abstract sparse conditional propagation algorithm,
+// modeled after SCCP, but with a customizable lattice function.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "sparseprop"
+#include "llvm/Analysis/SparsePropagation.h"
+#include "llvm/Constants.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/Streams.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+//                  AbstractLatticeFunction Implementation
+//===----------------------------------------------------------------------===//
+
+AbstractLatticeFunction::~AbstractLatticeFunction() {}
+
+/// PrintValue - Render the specified lattice value to the specified stream.
+void AbstractLatticeFunction::PrintValue(LatticeVal V, std::ostream &OS) {
+  if (V == UndefVal)
+    OS << "undefined";
+  else if (V == OverdefinedVal)
+    OS << "overdefined";
+  else if (V == UntrackedVal)
+    OS << "untracked";
+  else
+    OS << "unknown lattice value";
+}
+
+//===----------------------------------------------------------------------===//
+//                          SparseSolver Implementation
+//===----------------------------------------------------------------------===//
+
+/// getOrInitValueState - Return the LatticeVal object that corresponds to the
+/// value, initializing the value's state if it hasn't been entered into the
+/// map yet.   This function is necessary because not all values should start
+/// out in the underdefined state... Arguments should be overdefined, and
+/// constants should be marked as constants.
+///
+SparseSolver::LatticeVal SparseSolver::getOrInitValueState(Value *V) {
+  DenseMap<Value*, LatticeVal>::iterator I = ValueState.find(V);
+  if (I != ValueState.end()) return I->second;  // Common case, in the map
+  
+  LatticeVal LV;
+  if (LatticeFunc->IsUntrackedValue(V))
+    return LatticeFunc->getUntrackedVal();
+  else if (Constant *C = dyn_cast<Constant>(V))
+    LV = LatticeFunc->ComputeConstant(C);
+  else if (!isa<Instruction>(V))
+    // Non-instructions (e.g. formal arguments) are overdefined.
+    LV = LatticeFunc->getOverdefinedVal();
+  else
+    // All instructions are underdefined by default.
+    LV = LatticeFunc->getUndefVal();
+  
+  // If this value is untracked, don't add it to the map.
+  if (LV == LatticeFunc->getUntrackedVal())
+    return LV;
+  return ValueState[V] = LV;
+}
+
+/// UpdateState - When the state for some instruction is potentially updated,
+/// this function notices and adds I to the worklist if needed.
+void SparseSolver::UpdateState(Instruction &Inst, LatticeVal V) {
+  DenseMap<Value*, LatticeVal>::iterator I = ValueState.find(&Inst);
+  if (I != ValueState.end() && I->second == V)
+    return;  // No change.
+  
+  // An update.  Visit uses of I.
+  ValueState[&Inst] = V;
+  InstWorkList.push_back(&Inst);
+}
+
+/// MarkBlockExecutable - This method can be used by clients to mark all of
+/// the blocks that are known to be intrinsically live in the processed unit.
+void SparseSolver::MarkBlockExecutable(BasicBlock *BB) {
+  DOUT << "Marking Block Executable: " << BB->getNameStart() << "\n";
+  BBExecutable.insert(BB);   // Basic block is executable!
+  BBWorkList.push_back(BB);  // Add the block to the work list!
+}
+
+/// markEdgeExecutable - Mark a basic block as executable, adding it to the BB
+/// work list if it is not already executable...
+void SparseSolver::markEdgeExecutable(BasicBlock *Source, BasicBlock *Dest) {
+  if (!KnownFeasibleEdges.insert(Edge(Source, Dest)).second)
+    return;  // This edge is already known to be executable!
+  
+  if (BBExecutable.count(Dest)) {
+    DOUT << "Marking Edge Executable: " << Source->getNameStart()
+    << " -> " << Dest->getNameStart() << "\n";
+    
+    // The destination is already executable, but we just made an edge
+    // feasible that wasn't before.  Revisit the PHI nodes in the block
+    // because they have potentially new operands.
+    for (BasicBlock::iterator I = Dest->begin(); isa<PHINode>(I); ++I)
+      visitPHINode(*cast<PHINode>(I));
+    
+  } else {
+    MarkBlockExecutable(Dest);
+  }
+}
+
+
+/// getFeasibleSuccessors - Return a vector of booleans to indicate which
+/// successors are reachable from a given terminator instruction.
+void SparseSolver::getFeasibleSuccessors(TerminatorInst &TI,
+                                         SmallVectorImpl<bool> &Succs) {
+  Succs.resize(TI.getNumSuccessors());
+  if (TI.getNumSuccessors() == 0) return;
+  
+  if (BranchInst *BI = dyn_cast<BranchInst>(&TI)) {
+    if (BI->isUnconditional()) {
+      Succs[0] = true;
+      return;
+    }
+    
+    LatticeVal BCValue = getOrInitValueState(BI->getCondition());
+    if (BCValue == LatticeFunc->getOverdefinedVal() ||
+        BCValue == LatticeFunc->getUntrackedVal()) {
+      // Overdefined condition variables can branch either way.
+      Succs[0] = Succs[1] = true;
+      return;
+    }
+
+    // If undefined, neither is feasible yet.
+    if (BCValue == LatticeFunc->getUndefVal())
+      return;
+
+    Constant *C = LatticeFunc->GetConstant(BCValue, BI->getCondition(), *this);
+    if (C == 0 || !isa<ConstantInt>(C)) {
+      // Non-constant values can go either way.
+      Succs[0] = Succs[1] = true;
+      return;
+    }
+
+    // Constant condition variables mean the branch can only go a single way
+    Succs[C == ConstantInt::getFalse()] = true;
+    return;
+  }
+  
+  if (isa<InvokeInst>(TI)) {
+    // Invoke instructions successors are always executable.
+    // TODO: Could ask the lattice function if the value can throw.
+    Succs[0] = Succs[1] = true;
+    return;
+  }
+  
+  SwitchInst &SI = cast<SwitchInst>(TI);
+  LatticeVal SCValue = getOrInitValueState(SI.getCondition());
+  if (SCValue == LatticeFunc->getOverdefinedVal() ||
+      SCValue == LatticeFunc->getUntrackedVal()) {
+    // All destinations are executable!
+    Succs.assign(TI.getNumSuccessors(), true);
+    return;
+  }
+  
+  // If undefined, neither is feasible yet.
+  if (SCValue == LatticeFunc->getUndefVal())
+    return;
+  
+  Constant *C = LatticeFunc->GetConstant(SCValue, SI.getCondition(), *this);
+  if (C == 0 || !isa<ConstantInt>(C)) {
+    // All destinations are executable!
+    Succs.assign(TI.getNumSuccessors(), true);
+    return;
+  }
+  
+  Succs[SI.findCaseValue(cast<ConstantInt>(C))] = true;
+}
+
+
+/// isEdgeFeasible - Return true if the control flow edge from the 'From'
+/// basic block to the 'To' basic block is currently feasible...
+bool SparseSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
+  SmallVector<bool, 16> SuccFeasible;
+  TerminatorInst *TI = From->getTerminator();
+  getFeasibleSuccessors(*TI, SuccFeasible);
+  
+  for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
+    if (TI->getSuccessor(i) == To && SuccFeasible[i])
+      return true;
+  
+  return false;
+}
+
+void SparseSolver::visitTerminatorInst(TerminatorInst &TI) {
+  SmallVector<bool, 16> SuccFeasible;
+  getFeasibleSuccessors(TI, SuccFeasible);
+  
+  BasicBlock *BB = TI.getParent();
+  
+  // Mark all feasible successors executable...
+  for (unsigned i = 0, e = SuccFeasible.size(); i != e; ++i)
+    if (SuccFeasible[i])
+      markEdgeExecutable(BB, TI.getSuccessor(i));
+}
+
+void SparseSolver::visitPHINode(PHINode &PN) {
+  LatticeVal PNIV = getOrInitValueState(&PN);
+  LatticeVal Overdefined = LatticeFunc->getOverdefinedVal();
+  
+  // If this value is already overdefined (common) just return.
+  if (PNIV == Overdefined || PNIV == LatticeFunc->getUntrackedVal())
+    return;  // Quick exit
+  
+  // Super-extra-high-degree PHI nodes are unlikely to ever be interesting,
+  // and slow us down a lot.  Just mark them overdefined.
+  if (PN.getNumIncomingValues() > 64) {
+    UpdateState(PN, Overdefined);
+    return;
+  }
+  
+  // Look at all of the executable operands of the PHI node.  If any of them
+  // are overdefined, the PHI becomes overdefined as well.  Otherwise, ask the
+  // transfer function to give us the merge of the incoming values.
+  for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
+    // If the edge is not yet known to be feasible, it doesn't impact the PHI.
+    if (!isEdgeFeasible(PN.getIncomingBlock(i), PN.getParent()))
+      continue;
+    
+    // Merge in this value.
+    LatticeVal OpVal = getOrInitValueState(PN.getIncomingValue(i));
+    if (OpVal != PNIV)
+      PNIV = LatticeFunc->MergeValues(PNIV, OpVal);
+    
+    if (PNIV == Overdefined)
+      break;  // Rest of input values don't matter.
+  }
+
+  // Update the PHI with the compute value, which is the merge of the inputs.
+  UpdateState(PN, PNIV);
+}
+
+
+void SparseSolver::visitInst(Instruction &I) {
+  // PHIs are handled by the propagation logic, they are never passed into the
+  // transfer functions.
+  if (PHINode *PN = dyn_cast<PHINode>(&I))
+    return visitPHINode(*PN);
+  
+  // Otherwise, ask the transfer function what the result is.  If this is
+  // something that we care about, remember it.
+  LatticeVal IV = LatticeFunc->ComputeInstructionState(I, *this);
+  if (IV != LatticeFunc->getUntrackedVal())
+    UpdateState(I, IV);
+  
+  if (TerminatorInst *TI = dyn_cast<TerminatorInst>(&I))
+    visitTerminatorInst(*TI);
+}
+
+void SparseSolver::Solve(Function &F) {
+  MarkBlockExecutable(F.begin());
+  
+  // Process the work lists until they are empty!
+  while (!BBWorkList.empty() || !InstWorkList.empty()) {
+    // Process the instruction work list.
+    while (!InstWorkList.empty()) {
+      Instruction *I = InstWorkList.back();
+      InstWorkList.pop_back();
+
+      DOUT << "\nPopped off I-WL: " << *I;
+
+      // "I" got into the work list because it made a transition.  See if any
+      // users are both live and in need of updating.
+      for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+           UI != E; ++UI) {
+        Instruction *U = cast<Instruction>(*UI);
+        if (BBExecutable.count(U->getParent()))   // Inst is executable?
+          visitInst(*U);
+      }
+    }
+
+    // Process the basic block work list.
+    while (!BBWorkList.empty()) {
+      BasicBlock *BB = BBWorkList.back();
+      BBWorkList.pop_back();
+
+      DOUT << "\nPopped off BBWL: " << *BB;
+
+      // Notify all instructions in this basic block that they are newly
+      // executable.
+      for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
+        visitInst(*I);
+    }
+  }
+}
+
+void SparseSolver::Print(Function &F, std::ostream &OS) {
+  OS << "\nFUNCTION: " << F.getNameStr() << "\n";
+  for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+    if (!BBExecutable.count(BB))
+      OS << "INFEASIBLE: ";
+    OS << "\t";
+    if (BB->hasName())
+      OS << BB->getNameStr() << ":\n";
+    else
+      OS << "; anon bb\n";
+    for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
+      LatticeFunc->PrintValue(getLatticeState(I), OS);
+      OS << *I;
+    }
+    
+    OS << "\n";
+  }
+}
+