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diff --git a/contrib/llvm/lib/Transforms/Utils/LCSSA.cpp b/contrib/llvm/lib/Transforms/Utils/LCSSA.cpp
new file mode 100644
index 000000000000..f15e8d59276b
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+++ b/contrib/llvm/lib/Transforms/Utils/LCSSA.cpp
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+//===-- LCSSA.cpp - Convert loops into loop-closed SSA form ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass transforms loops by placing phi nodes at the end of the loops for
+// all values that are live across the loop boundary.  For example, it turns
+// the left into the right code:
+// 
+// for (...)                for (...)
+//   if (c)                   if (c)
+//     X1 = ...                 X1 = ...
+//   else                     else
+//     X2 = ...                 X2 = ...
+//   X3 = phi(X1, X2)         X3 = phi(X1, X2)
+// ... = X3 + 4             X4 = phi(X3)
+//                          ... = X4 + 4
+//
+// This is still valid LLVM; the extra phi nodes are purely redundant, and will
+// be trivially eliminated by InstCombine.  The major benefit of this 
+// transformation is that it makes many other loop optimizations, such as 
+// LoopUnswitching, simpler.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "lcssa"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/PredIteratorCache.h"
+#include "llvm/Transforms/Utils/SSAUpdater.h"
+using namespace llvm;
+
+STATISTIC(NumLCSSA, "Number of live out of a loop variables");
+
+namespace {
+  struct LCSSA : public LoopPass {
+    static char ID; // Pass identification, replacement for typeid
+    LCSSA() : LoopPass(ID) {
+      initializeLCSSAPass(*PassRegistry::getPassRegistry());
+    }
+
+    // Cached analysis information for the current function.
+    DominatorTree *DT;
+    LoopInfo *LI;
+    ScalarEvolution *SE;
+    PredIteratorCache PredCache;
+    Loop *L;
+    
+    virtual bool runOnLoop(Loop *L, LPPassManager &LPM);
+
+    /// This transformation requires natural loop information & requires that
+    /// loop preheaders be inserted into the CFG.  It maintains both of these,
+    /// as well as the CFG.  It also requires dominator information.
+    ///
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesCFG();
+
+      AU.addRequired<DominatorTree>();
+      AU.addRequired<LoopInfo>();
+      AU.addPreservedID(LoopSimplifyID);
+      AU.addPreserved<ScalarEvolution>();
+    }
+  private:
+    bool ProcessInstruction(Instruction *Inst,
+                            const SmallVectorImpl<BasicBlock*> &ExitBlocks);
+    
+    /// verifyAnalysis() - Verify loop nest.
+    virtual void verifyAnalysis() const {
+      // Check the special guarantees that LCSSA makes.
+      assert(L->isLCSSAForm(*DT) && "LCSSA form not preserved!");
+    }
+  };
+}
+  
+char LCSSA::ID = 0;
+INITIALIZE_PASS_BEGIN(LCSSA, "lcssa", "Loop-Closed SSA Form Pass", false, false)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_DEPENDENCY(LoopInfo)
+INITIALIZE_PASS_END(LCSSA, "lcssa", "Loop-Closed SSA Form Pass", false, false)
+
+Pass *llvm::createLCSSAPass() { return new LCSSA(); }
+char &llvm::LCSSAID = LCSSA::ID;
+
+
+/// BlockDominatesAnExit - Return true if the specified block dominates at least
+/// one of the blocks in the specified list.
+static bool BlockDominatesAnExit(BasicBlock *BB,
+                                 const SmallVectorImpl<BasicBlock*> &ExitBlocks,
+                                 DominatorTree *DT) {
+  DomTreeNode *DomNode = DT->getNode(BB);
+  for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i)
+    if (DT->dominates(DomNode, DT->getNode(ExitBlocks[i])))
+      return true;
+
+  return false;
+}
+
+
+/// runOnFunction - Process all loops in the function, inner-most out.
+bool LCSSA::runOnLoop(Loop *TheLoop, LPPassManager &LPM) {
+  L = TheLoop;
+  
+  DT = &getAnalysis<DominatorTree>();
+  LI = &getAnalysis<LoopInfo>();
+  SE = getAnalysisIfAvailable<ScalarEvolution>();
+
+  // Get the set of exiting blocks.
+  SmallVector<BasicBlock*, 8> ExitBlocks;
+  L->getExitBlocks(ExitBlocks);
+  
+  if (ExitBlocks.empty())
+    return false;
+  
+  // Look at all the instructions in the loop, checking to see if they have uses
+  // outside the loop.  If so, rewrite those uses.
+  bool MadeChange = false;
+  
+  for (Loop::block_iterator BBI = L->block_begin(), E = L->block_end();
+       BBI != E; ++BBI) {
+    BasicBlock *BB = *BBI;
+    
+    // For large loops, avoid use-scanning by using dominance information:  In
+    // particular, if a block does not dominate any of the loop exits, then none
+    // of the values defined in the block could be used outside the loop.
+    if (!BlockDominatesAnExit(BB, ExitBlocks, DT))
+      continue;
+    
+    for (BasicBlock::iterator I = BB->begin(), E = BB->end();
+         I != E; ++I) {
+      // Reject two common cases fast: instructions with no uses (like stores)
+      // and instructions with one use that is in the same block as this.
+      if (I->use_empty() ||
+          (I->hasOneUse() && I->use_back()->getParent() == BB &&
+           !isa<PHINode>(I->use_back())))
+        continue;
+      
+      MadeChange |= ProcessInstruction(I, ExitBlocks);
+    }
+  }
+
+  // If we modified the code, remove any caches about the loop from SCEV to
+  // avoid dangling entries.
+  // FIXME: This is a big hammer, can we clear the cache more selectively?
+  if (SE && MadeChange)
+    SE->forgetLoop(L);
+  
+  assert(L->isLCSSAForm(*DT));
+  PredCache.clear();
+
+  return MadeChange;
+}
+
+/// isExitBlock - Return true if the specified block is in the list.
+static bool isExitBlock(BasicBlock *BB,
+                        const SmallVectorImpl<BasicBlock*> &ExitBlocks) {
+  for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i)
+    if (ExitBlocks[i] == BB)
+      return true;
+  return false;
+}
+
+/// ProcessInstruction - Given an instruction in the loop, check to see if it
+/// has any uses that are outside the current loop.  If so, insert LCSSA PHI
+/// nodes and rewrite the uses.
+bool LCSSA::ProcessInstruction(Instruction *Inst,
+                               const SmallVectorImpl<BasicBlock*> &ExitBlocks) {
+  SmallVector<Use*, 16> UsesToRewrite;
+  
+  BasicBlock *InstBB = Inst->getParent();
+  
+  for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end();
+       UI != E; ++UI) {
+    User *U = *UI;
+    BasicBlock *UserBB = cast<Instruction>(U)->getParent();
+    if (PHINode *PN = dyn_cast<PHINode>(U))
+      UserBB = PN->getIncomingBlock(UI);
+    
+    if (InstBB != UserBB && !L->contains(UserBB))
+      UsesToRewrite.push_back(&UI.getUse());
+  }
+
+  // If there are no uses outside the loop, exit with no change.
+  if (UsesToRewrite.empty()) return false;
+  
+  ++NumLCSSA; // We are applying the transformation
+
+  // Invoke instructions are special in that their result value is not available
+  // along their unwind edge. The code below tests to see whether DomBB dominates
+  // the value, so adjust DomBB to the normal destination block, which is
+  // effectively where the value is first usable.
+  BasicBlock *DomBB = Inst->getParent();
+  if (InvokeInst *Inv = dyn_cast<InvokeInst>(Inst))
+    DomBB = Inv->getNormalDest();
+
+  DomTreeNode *DomNode = DT->getNode(DomBB);
+
+  SmallVector<PHINode*, 16> AddedPHIs;
+
+  SSAUpdater SSAUpdate;
+  SSAUpdate.Initialize(Inst->getType(), Inst->getName());
+  
+  // Insert the LCSSA phi's into all of the exit blocks dominated by the
+  // value, and add them to the Phi's map.
+  for (SmallVectorImpl<BasicBlock*>::const_iterator BBI = ExitBlocks.begin(),
+      BBE = ExitBlocks.end(); BBI != BBE; ++BBI) {
+    BasicBlock *ExitBB = *BBI;
+    if (!DT->dominates(DomNode, DT->getNode(ExitBB))) continue;
+    
+    // If we already inserted something for this BB, don't reprocess it.
+    if (SSAUpdate.HasValueForBlock(ExitBB)) continue;
+    
+    PHINode *PN = PHINode::Create(Inst->getType(),
+                                  PredCache.GetNumPreds(ExitBB),
+                                  Inst->getName()+".lcssa",
+                                  ExitBB->begin());
+
+    // Add inputs from inside the loop for this PHI.
+    for (BasicBlock **PI = PredCache.GetPreds(ExitBB); *PI; ++PI) {
+      PN->addIncoming(Inst, *PI);
+
+      // If the exit block has a predecessor not within the loop, arrange for
+      // the incoming value use corresponding to that predecessor to be
+      // rewritten in terms of a different LCSSA PHI.
+      if (!L->contains(*PI))
+        UsesToRewrite.push_back(
+          &PN->getOperandUse(
+            PN->getOperandNumForIncomingValue(PN->getNumIncomingValues()-1)));
+    }
+
+    AddedPHIs.push_back(PN);
+    
+    // Remember that this phi makes the value alive in this block.
+    SSAUpdate.AddAvailableValue(ExitBB, PN);
+  }
+
+  // Rewrite all uses outside the loop in terms of the new PHIs we just
+  // inserted.
+  for (unsigned i = 0, e = UsesToRewrite.size(); i != e; ++i) {
+    // If this use is in an exit block, rewrite to use the newly inserted PHI.
+    // This is required for correctness because SSAUpdate doesn't handle uses in
+    // the same block.  It assumes the PHI we inserted is at the end of the
+    // block.
+    Instruction *User = cast<Instruction>(UsesToRewrite[i]->getUser());
+    BasicBlock *UserBB = User->getParent();
+    if (PHINode *PN = dyn_cast<PHINode>(User))
+      UserBB = PN->getIncomingBlock(*UsesToRewrite[i]);
+
+    if (isa<PHINode>(UserBB->begin()) &&
+        isExitBlock(UserBB, ExitBlocks)) {
+      // Tell the VHs that the uses changed. This updates SCEV's caches.
+      if (UsesToRewrite[i]->get()->hasValueHandle())
+        ValueHandleBase::ValueIsRAUWd(*UsesToRewrite[i], UserBB->begin());
+      UsesToRewrite[i]->set(UserBB->begin());
+      continue;
+    }
+    
+    // Otherwise, do full PHI insertion.
+    SSAUpdate.RewriteUse(*UsesToRewrite[i]);
+  }
+
+  // Remove PHI nodes that did not have any uses rewritten.
+  for (unsigned i = 0, e = AddedPHIs.size(); i != e; ++i) {
+    if (AddedPHIs[i]->use_empty())
+      AddedPHIs[i]->eraseFromParent();
+  }
+  
+  return true;
+}
+