Add some advice

llvm-svn: 29324

5 files changed, 1230 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/LowerAllocations.cpp b/llvm/lib/Transforms/Utils/LowerAllocations.cpp
new file mode 100644
index 00000000000..eab64681e57
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/LowerAllocations.cpp
@@ -0,0 +1,206 @@
+//===- LowerAllocations.cpp - Reduce malloc & free insts to calls ---------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+//
+// The LowerAllocations transformation is a target-dependent tranformation
+// because it depends on the size of data types and alignment constraints.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
+#include "llvm/Module.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/Constants.h"
+#include "llvm/Pass.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Support/Visibility.h"
+using namespace llvm;
+
+namespace {
+  Statistic<> NumLowered("lowerallocs", "Number of allocations lowered");
+
+  /// LowerAllocations - Turn malloc and free instructions into %malloc and
+  /// %free calls.
+  ///
+  class VISIBILITY_HIDDEN LowerAllocations : public BasicBlockPass {
+    Function *MallocFunc;   // Functions in the module we are processing
+    Function *FreeFunc;     // Initialized by doInitialization
+    bool LowerMallocArgToInteger;
+  public:
+    LowerAllocations(bool LowerToInt = false)
+      : MallocFunc(0), FreeFunc(0), LowerMallocArgToInteger(LowerToInt) {}
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addRequired<TargetData>();
+      AU.setPreservesCFG();
+
+      // This is a cluster of orthogonal Transforms:	
+      AU.addPreserved<UnifyFunctionExitNodes>();
+      AU.addPreservedID(PromoteMemoryToRegisterID);
+      AU.addPreservedID(LowerSelectID);
+      AU.addPreservedID(LowerSwitchID);
+      AU.addPreservedID(LowerInvokePassID);
+    }
+
+    /// doPassInitialization - For the lower allocations pass, this ensures that
+    /// a module contains a declaration for a malloc and a free function.
+    ///
+    bool doInitialization(Module &M);
+
+    virtual bool doInitialization(Function &F) {
+      return BasicBlockPass::doInitialization(F);
+    }
+
+    /// runOnBasicBlock - This method does the actual work of converting
+    /// instructions over, assuming that the pass has already been initialized.
+    ///
+    bool runOnBasicBlock(BasicBlock &BB);
+  };
+
+  RegisterOpt<LowerAllocations>
+  X("lowerallocs", "Lower allocations from instructions to calls");
+}
+
+// Publically exposed interface to pass...
+const PassInfo *llvm::LowerAllocationsID = X.getPassInfo();
+// createLowerAllocationsPass - Interface to this file...
+FunctionPass *llvm::createLowerAllocationsPass(bool LowerMallocArgToInteger) {
+  return new LowerAllocations(LowerMallocArgToInteger);
+}
+
+
+// doInitialization - For the lower allocations pass, this ensures that a
+// module contains a declaration for a malloc and a free function.
+//
+// This function is always successful.
+//
+bool LowerAllocations::doInitialization(Module &M) {
+  const Type *SBPTy = PointerType::get(Type::SByteTy);
+  MallocFunc = M.getNamedFunction("malloc");
+  FreeFunc   = M.getNamedFunction("free");
+
+  if (MallocFunc == 0) {
+    // Prototype malloc as "void* malloc(...)", because we don't know in
+    // doInitialization whether size_t is int or long.
+    FunctionType *FT = FunctionType::get(SBPTy,std::vector<const Type*>(),true);
+    MallocFunc = M.getOrInsertFunction("malloc", FT);
+  }
+  if (FreeFunc == 0)
+    FreeFunc = M.getOrInsertFunction("free"  , Type::VoidTy, SBPTy, (Type *)0);
+
+  return true;
+}
+
+// runOnBasicBlock - This method does the actual work of converting
+// instructions over, assuming that the pass has already been initialized.
+//
+bool LowerAllocations::runOnBasicBlock(BasicBlock &BB) {
+  bool Changed = false;
+  assert(MallocFunc && FreeFunc && "Pass not initialized!");
+
+  BasicBlock::InstListType &BBIL = BB.getInstList();
+
+  const TargetData &TD = getAnalysis<TargetData>();
+  const Type *IntPtrTy = TD.getIntPtrType();
+
+  // Loop over all of the instructions, looking for malloc or free instructions
+  for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I) {
+    if (MallocInst *MI = dyn_cast<MallocInst>(I)) {
+      const Type *AllocTy = MI->getType()->getElementType();
+
+      // malloc(type) becomes sbyte *malloc(size)
+      Value *MallocArg;
+      if (LowerMallocArgToInteger)
+        MallocArg = ConstantUInt::get(Type::ULongTy, TD.getTypeSize(AllocTy));
+      else
+        MallocArg = ConstantExpr::getSizeOf(AllocTy);
+      MallocArg = ConstantExpr::getCast(cast<Constant>(MallocArg), IntPtrTy);
+
+      if (MI->isArrayAllocation()) {
+        if (isa<ConstantInt>(MallocArg) &&
+            cast<ConstantInt>(MallocArg)->getRawValue() == 1) {
+          MallocArg = MI->getOperand(0);         // Operand * 1 = Operand
+        } else if (Constant *CO = dyn_cast<Constant>(MI->getOperand(0))) {
+          CO = ConstantExpr::getCast(CO, IntPtrTy);
+          MallocArg = ConstantExpr::getMul(CO, cast<Constant>(MallocArg));
+        } else {
+          Value *Scale = MI->getOperand(0);
+          if (Scale->getType() != IntPtrTy)
+            Scale = new CastInst(Scale, IntPtrTy, "", I);
+
+          // Multiply it by the array size if necessary...
+          MallocArg = BinaryOperator::create(Instruction::Mul, Scale,
+                                             MallocArg, "", I);
+        }
+      }
+
+      const FunctionType *MallocFTy = MallocFunc->getFunctionType();
+      std::vector<Value*> MallocArgs;
+
+      if (MallocFTy->getNumParams() > 0 || MallocFTy->isVarArg()) {
+        if (MallocFTy->isVarArg()) {
+          if (MallocArg->getType() != IntPtrTy)
+            MallocArg = new CastInst(MallocArg, IntPtrTy, "", I);
+        } else if (MallocFTy->getNumParams() > 0 &&
+                   MallocFTy->getParamType(0) != Type::UIntTy)
+          MallocArg = new CastInst(MallocArg, MallocFTy->getParamType(0), "",I);
+        MallocArgs.push_back(MallocArg);
+      }
+
+      // If malloc is prototyped to take extra arguments, pass nulls.
+      for (unsigned i = 1; i < MallocFTy->getNumParams(); ++i)
+       MallocArgs.push_back(Constant::getNullValue(MallocFTy->getParamType(i)));
+
+      // Create the call to Malloc...
+      CallInst *MCall = new CallInst(MallocFunc, MallocArgs, "", I);
+      MCall->setTailCall();
+
+      // Create a cast instruction to convert to the right type...
+      Value *MCast;
+      if (MCall->getType() != Type::VoidTy)
+        MCast = new CastInst(MCall, MI->getType(), "", I);
+      else
+        MCast = Constant::getNullValue(MI->getType());
+
+      // Replace all uses of the old malloc inst with the cast inst
+      MI->replaceAllUsesWith(MCast);
+      I = --BBIL.erase(I);         // remove and delete the malloc instr...
+      Changed = true;
+      ++NumLowered;
+    } else if (FreeInst *FI = dyn_cast<FreeInst>(I)) {
+      const FunctionType *FreeFTy = FreeFunc->getFunctionType();
+      std::vector<Value*> FreeArgs;
+
+      if (FreeFTy->getNumParams() > 0 || FreeFTy->isVarArg()) {
+        Value *MCast = FI->getOperand(0);
+        if (FreeFTy->getNumParams() > 0 &&
+            FreeFTy->getParamType(0) != MCast->getType())
+          MCast = new CastInst(MCast, FreeFTy->getParamType(0), "", I);
+        FreeArgs.push_back(MCast);
+      }
+
+      // If malloc is prototyped to take extra arguments, pass nulls.
+      for (unsigned i = 1; i < FreeFTy->getNumParams(); ++i)
+       FreeArgs.push_back(Constant::getNullValue(FreeFTy->getParamType(i)));
+
+      // Insert a call to the free function...
+      (new CallInst(FreeFunc, FreeArgs, "", I))->setTailCall();
+
+      // Delete the old free instruction
+      I = --BBIL.erase(I);
+      Changed = true;
+      ++NumLowered;
+    }
+  }
+
+  return Changed;
+}
+
diff --git a/llvm/lib/Transforms/Utils/LowerInvoke.cpp b/llvm/lib/Transforms/Utils/LowerInvoke.cpp
new file mode 100644
index 00000000000..b5f652c154c
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/LowerInvoke.cpp
@@ -0,0 +1,592 @@
+//===- LowerInvoke.cpp - Eliminate Invoke & Unwind instructions -----------===//
+//
+//                     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 transformation is designed for use by code generators which do not yet
+// support stack unwinding.  This pass supports two models of exception handling
+// lowering, the 'cheap' support and the 'expensive' support.
+//
+// 'Cheap' exception handling support gives the program the ability to execute
+// any program which does not "throw an exception", by turning 'invoke'
+// instructions into calls and by turning 'unwind' instructions into calls to
+// abort().  If the program does dynamically use the unwind instruction, the
+// program will print a message then abort.
+//
+// 'Expensive' exception handling support gives the full exception handling
+// support to the program at the cost of making the 'invoke' instruction
+// really expensive.  It basically inserts setjmp/longjmp calls to emulate the
+// exception handling as necessary.
+//
+// Because the 'expensive' support slows down programs a lot, and EH is only
+// used for a subset of the programs, it must be specifically enabled by an
+// option.
+//
+// Note that after this pass runs the CFG is not entirely accurate (exceptional
+// control flow edges are not correct anymore) so only very simple things should
+// be done after the lowerinvoke pass has run (like generation of native code).
+// This should not be used as a general purpose "my LLVM-to-LLVM pass doesn't
+// support the invoke instruction yet" lowering pass.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Visibility.h"
+#include <csetjmp>
+using namespace llvm;
+
+namespace {
+  Statistic<> NumInvokes("lowerinvoke", "Number of invokes replaced");
+  Statistic<> NumUnwinds("lowerinvoke", "Number of unwinds replaced");
+  Statistic<> NumSpilled("lowerinvoke",
+                         "Number of registers live across unwind edges");
+  cl::opt<bool> ExpensiveEHSupport("enable-correct-eh-support",
+ cl::desc("Make the -lowerinvoke pass insert expensive, but correct, EH code"));
+
+  class VISIBILITY_HIDDEN LowerInvoke : public FunctionPass {
+    // Used for both models.
+    Function *WriteFn;
+    Function *AbortFn;
+    Value *AbortMessage;
+    unsigned AbortMessageLength;
+
+    // Used for expensive EH support.
+    const Type *JBLinkTy;
+    GlobalVariable *JBListHead;
+    Function *SetJmpFn, *LongJmpFn;
+  public:
+    LowerInvoke(unsigned Size = 200, unsigned Align = 0) : JumpBufSize(Size),
+      JumpBufAlign(Align) {}
+    bool doInitialization(Module &M);
+    bool runOnFunction(Function &F);
+ 
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      // This is a cluster of orthogonal Transforms	
+      AU.addPreservedID(PromoteMemoryToRegisterID);
+      AU.addPreservedID(LowerSelectID);
+      AU.addPreservedID(LowerSwitchID);
+      AU.addPreservedID(LowerAllocationsID);
+    }
+       
+  private:
+    void createAbortMessage();
+    void writeAbortMessage(Instruction *IB);
+    bool insertCheapEHSupport(Function &F);
+    void splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes);
+    void rewriteExpensiveInvoke(InvokeInst *II, unsigned InvokeNo,
+                                AllocaInst *InvokeNum, SwitchInst *CatchSwitch);
+    bool insertExpensiveEHSupport(Function &F);
+    
+    unsigned JumpBufSize;
+    unsigned JumpBufAlign;
+  };
+
+  RegisterOpt<LowerInvoke>
+  X("lowerinvoke", "Lower invoke and unwind, for unwindless code generators");
+}
+
+const PassInfo *llvm::LowerInvokePassID = X.getPassInfo();
+
+// Public Interface To the LowerInvoke pass.
+FunctionPass *llvm::createLowerInvokePass(unsigned JumpBufSize, 
+                                          unsigned JumpBufAlign) { 
+  return new LowerInvoke(JumpBufSize, JumpBufAlign); 
+}
+
+// doInitialization - Make sure that there is a prototype for abort in the
+// current module.
+bool LowerInvoke::doInitialization(Module &M) {
+  const Type *VoidPtrTy = PointerType::get(Type::SByteTy);
+  AbortMessage = 0;
+  if (ExpensiveEHSupport) {
+    // Insert a type for the linked list of jump buffers.
+    const Type *JmpBufTy = ArrayType::get(VoidPtrTy, JumpBufSize);
+
+    { // The type is recursive, so use a type holder.
+      std::vector<const Type*> Elements;
+      Elements.push_back(JmpBufTy);
+      OpaqueType *OT = OpaqueType::get();
+      Elements.push_back(PointerType::get(OT));
+      PATypeHolder JBLType(StructType::get(Elements));
+      OT->refineAbstractTypeTo(JBLType.get());  // Complete the cycle.
+      JBLinkTy = JBLType.get();
+      M.addTypeName("llvm.sjljeh.jmpbufty", JBLinkTy);
+    }
+
+    const Type *PtrJBList = PointerType::get(JBLinkTy);
+
+    // Now that we've done that, insert the jmpbuf list head global, unless it
+    // already exists.
+    if (!(JBListHead = M.getGlobalVariable("llvm.sjljeh.jblist", PtrJBList)))
+      JBListHead = new GlobalVariable(PtrJBList, false,
+                                      GlobalValue::LinkOnceLinkage,
+                                      Constant::getNullValue(PtrJBList),
+                                      "llvm.sjljeh.jblist", &M);
+    SetJmpFn = M.getOrInsertFunction("llvm.setjmp", Type::IntTy,
+                                     PointerType::get(JmpBufTy), (Type *)0);
+    LongJmpFn = M.getOrInsertFunction("llvm.longjmp", Type::VoidTy,
+                                      PointerType::get(JmpBufTy),
+                                      Type::IntTy, (Type *)0);
+  }
+
+  // We need the 'write' and 'abort' functions for both models.
+  AbortFn = M.getOrInsertFunction("abort", Type::VoidTy, (Type *)0);
+
+  // Unfortunately, 'write' can end up being prototyped in several different
+  // ways.  If the user defines a three (or more) operand function named 'write'
+  // we will use their prototype.  We _do not_ want to insert another instance
+  // of a write prototype, because we don't know that the funcresolve pass will
+  // run after us.  If there is a definition of a write function, but it's not
+  // suitable for our uses, we just don't emit write calls.  If there is no
+  // write prototype at all, we just add one.
+  if (Function *WF = M.getNamedFunction("write")) {
+    if (WF->getFunctionType()->getNumParams() > 3 ||
+        WF->getFunctionType()->isVarArg())
+      WriteFn = WF;
+    else
+      WriteFn = 0;
+  } else {
+    WriteFn = M.getOrInsertFunction("write", Type::VoidTy, Type::IntTy,
+                                    VoidPtrTy, Type::IntTy, (Type *)0);
+  }
+  return true;
+}
+
+void LowerInvoke::createAbortMessage() {
+  Module &M = *WriteFn->getParent();
+  if (ExpensiveEHSupport) {
+    // The abort message for expensive EH support tells the user that the
+    // program 'unwound' without an 'invoke' instruction.
+    Constant *Msg =
+      ConstantArray::get("ERROR: Exception thrown, but not caught!\n");
+    AbortMessageLength = Msg->getNumOperands()-1;  // don't include \0
+
+    GlobalVariable *MsgGV = new GlobalVariable(Msg->getType(), true,
+                                               GlobalValue::InternalLinkage,
+                                               Msg, "abortmsg", &M);
+    std::vector<Constant*> GEPIdx(2, Constant::getNullValue(Type::IntTy));
+    AbortMessage = ConstantExpr::getGetElementPtr(MsgGV, GEPIdx);
+  } else {
+    // The abort message for cheap EH support tells the user that EH is not
+    // enabled.
+    Constant *Msg =
+      ConstantArray::get("Exception handler needed, but not enabled.  Recompile"
+                         " program with -enable-correct-eh-support.\n");
+    AbortMessageLength = Msg->getNumOperands()-1;  // don't include \0
+
+    GlobalVariable *MsgGV = new GlobalVariable(Msg->getType(), true,
+                                               GlobalValue::InternalLinkage,
+                                               Msg, "abortmsg", &M);
+    std::vector<Constant*> GEPIdx(2, Constant::getNullValue(Type::IntTy));
+    AbortMessage = ConstantExpr::getGetElementPtr(MsgGV, GEPIdx);
+  }
+}
+
+
+void LowerInvoke::writeAbortMessage(Instruction *IB) {
+  if (WriteFn) {
+    if (AbortMessage == 0) createAbortMessage();
+
+    // These are the arguments we WANT...
+    std::vector<Value*> Args;
+    Args.push_back(ConstantInt::get(Type::IntTy, 2));
+    Args.push_back(AbortMessage);
+    Args.push_back(ConstantInt::get(Type::IntTy, AbortMessageLength));
+
+    // If the actual declaration of write disagrees, insert casts as
+    // appropriate.
+    const FunctionType *FT = WriteFn->getFunctionType();
+    unsigned NumArgs = FT->getNumParams();
+    for (unsigned i = 0; i != 3; ++i)
+      if (i < NumArgs && FT->getParamType(i) != Args[i]->getType())
+        Args[i] = ConstantExpr::getCast(cast<Constant>(Args[i]),
+                                        FT->getParamType(i));
+
+    (new CallInst(WriteFn, Args, "", IB))->setTailCall();
+  }
+}
+
+bool LowerInvoke::insertCheapEHSupport(Function &F) {
+  bool Changed = false;
+  for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
+    if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
+      // Insert a normal call instruction...
+      std::string Name = II->getName(); II->setName("");
+      CallInst *NewCall = new CallInst(II->getCalledValue(),
+                                       std::vector<Value*>(II->op_begin()+3,
+                                                       II->op_end()), Name, II);
+      NewCall->setCallingConv(II->getCallingConv());
+      II->replaceAllUsesWith(NewCall);
+
+      // Insert an unconditional branch to the normal destination.
+      new BranchInst(II->getNormalDest(), II);
+
+      // Remove any PHI node entries from the exception destination.
+      II->getUnwindDest()->removePredecessor(BB);
+
+      // Remove the invoke instruction now.
+      BB->getInstList().erase(II);
+
+      ++NumInvokes; Changed = true;
+    } else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
+      // Insert a new call to write(2, AbortMessage, AbortMessageLength);
+      writeAbortMessage(UI);
+
+      // Insert a call to abort()
+      (new CallInst(AbortFn, std::vector<Value*>(), "", UI))->setTailCall();
+
+      // Insert a return instruction.  This really should be a "barrier", as it
+      // is unreachable.
+      new ReturnInst(F.getReturnType() == Type::VoidTy ? 0 :
+                            Constant::getNullValue(F.getReturnType()), UI);
+
+      // Remove the unwind instruction now.
+      BB->getInstList().erase(UI);
+
+      ++NumUnwinds; Changed = true;
+    }
+  return Changed;
+}
+
+/// rewriteExpensiveInvoke - Insert code and hack the function to replace the
+/// specified invoke instruction with a call.
+void LowerInvoke::rewriteExpensiveInvoke(InvokeInst *II, unsigned InvokeNo,
+                                         AllocaInst *InvokeNum,
+                                         SwitchInst *CatchSwitch) {
+  ConstantUInt *InvokeNoC = ConstantUInt::get(Type::UIntTy, InvokeNo);
+
+  // Insert a store of the invoke num before the invoke and store zero into the
+  // location afterward.
+  new StoreInst(InvokeNoC, InvokeNum, true, II);  // volatile
+  
+  BasicBlock::iterator NI = II->getNormalDest()->begin();
+  while (isa<PHINode>(NI)) ++NI;
+  // nonvolatile.
+  new StoreInst(Constant::getNullValue(Type::UIntTy), InvokeNum, false, NI);
+  
+  // Add a switch case to our unwind block.
+  CatchSwitch->addCase(InvokeNoC, II->getUnwindDest());
+  
+  // Insert a normal call instruction.
+  std::string Name = II->getName(); II->setName("");
+  CallInst *NewCall = new CallInst(II->getCalledValue(),
+                                   std::vector<Value*>(II->op_begin()+3,
+                                                       II->op_end()), Name,
+                                   II);
+  NewCall->setCallingConv(II->getCallingConv());
+  II->replaceAllUsesWith(NewCall);
+  
+  // Replace the invoke with an uncond branch.
+  new BranchInst(II->getNormalDest(), NewCall->getParent());
+  II->eraseFromParent();
+}
+
+/// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until
+/// we reach blocks we've already seen.
+static void MarkBlocksLiveIn(BasicBlock *BB, std::set<BasicBlock*> &LiveBBs) {
+  if (!LiveBBs.insert(BB).second) return; // already been here.
+  
+  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
+    MarkBlocksLiveIn(*PI, LiveBBs);  
+}
+
+// First thing we need to do is scan the whole function for values that are
+// live across unwind edges.  Each value that is live across an unwind edge
+// we spill into a stack location, guaranteeing that there is nothing live
+// across the unwind edge.  This process also splits all critical edges
+// coming out of invoke's.
+void LowerInvoke::
+splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes) {
+  // First step, split all critical edges from invoke instructions.
+  for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
+    InvokeInst *II = Invokes[i];
+    SplitCriticalEdge(II, 0, this);
+    SplitCriticalEdge(II, 1, this);
+    assert(!isa<PHINode>(II->getNormalDest()) &&
+           !isa<PHINode>(II->getUnwindDest()) &&
+           "critical edge splitting left single entry phi nodes?");
+  }
+
+  Function *F = Invokes.back()->getParent()->getParent();
+  
+  // To avoid having to handle incoming arguments specially, we lower each arg
+  // to a copy instruction in the entry block.  This ensure that the argument
+  // value itself cannot be live across the entry block.
+  BasicBlock::iterator AfterAllocaInsertPt = F->begin()->begin();
+  while (isa<AllocaInst>(AfterAllocaInsertPt) &&
+        isa<ConstantInt>(cast<AllocaInst>(AfterAllocaInsertPt)->getArraySize()))
+    ++AfterAllocaInsertPt;
+  for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
+       AI != E; ++AI) {
+    CastInst *NC = new CastInst(AI, AI->getType(), AI->getName()+".tmp",
+                                AfterAllocaInsertPt);
+    AI->replaceAllUsesWith(NC);
+    NC->setOperand(0, AI);
+  }
+  
+  // Finally, scan the code looking for instructions with bad live ranges.
+  for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
+    for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) {
+      // Ignore obvious cases we don't have to handle.  In particular, most
+      // instructions either have no uses or only have a single use inside the
+      // current block.  Ignore them quickly.
+      Instruction *Inst = II;
+      if (Inst->use_empty()) continue;
+      if (Inst->hasOneUse() &&
+          cast<Instruction>(Inst->use_back())->getParent() == BB &&
+          !isa<PHINode>(Inst->use_back())) continue;
+      
+      // If this is an alloca in the entry block, it's not a real register
+      // value.
+      if (AllocaInst *AI = dyn_cast<AllocaInst>(Inst))
+        if (isa<ConstantInt>(AI->getArraySize()) && BB == F->begin())
+          continue;
+      
+      // Avoid iterator invalidation by copying users to a temporary vector.
+      std::vector<Instruction*> Users;
+      for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end();
+           UI != E; ++UI) {
+        Instruction *User = cast<Instruction>(*UI);
+        if (User->getParent() != BB || isa<PHINode>(User))
+          Users.push_back(User);
+      }
+
+      // Scan all of the uses and see if the live range is live across an unwind
+      // edge.  If we find a use live across an invoke edge, create an alloca
+      // and spill the value.
+      AllocaInst *SpillLoc = 0;
+      std::set<InvokeInst*> InvokesWithStoreInserted;
+
+      // Find all of the blocks that this value is live in.
+      std::set<BasicBlock*> LiveBBs;
+      LiveBBs.insert(Inst->getParent());
+      while (!Users.empty()) {
+        Instruction *U = Users.back();
+        Users.pop_back();
+        
+        if (!isa<PHINode>(U)) {
+          MarkBlocksLiveIn(U->getParent(), LiveBBs);
+        } else {
+          // Uses for a PHI node occur in their predecessor block.
+          PHINode *PN = cast<PHINode>(U);
+          for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+            if (PN->getIncomingValue(i) == Inst)
+              MarkBlocksLiveIn(PN->getIncomingBlock(i), LiveBBs);
+        }
+      }
+      
+      // Now that we know all of the blocks that this thing is live in, see if
+      // it includes any of the unwind locations.
+      bool NeedsSpill = false;
+      for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
+        BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest();
+        if (UnwindBlock != BB && LiveBBs.count(UnwindBlock)) {
+          NeedsSpill = true;
+        }
+      }
+
+      // If we decided we need a spill, do it.
+      if (NeedsSpill) {
+        ++NumSpilled;
+        DemoteRegToStack(*Inst, true);
+      }
+    }
+}
+
+bool LowerInvoke::insertExpensiveEHSupport(Function &F) {
+  std::vector<ReturnInst*> Returns;
+  std::vector<UnwindInst*> Unwinds;
+  std::vector<InvokeInst*> Invokes;
+
+  for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
+    if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
+      // Remember all return instructions in case we insert an invoke into this
+      // function.
+      Returns.push_back(RI);
+    } else if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
+      Invokes.push_back(II);
+    } else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
+      Unwinds.push_back(UI);
+    }
+
+  if (Unwinds.empty() && Invokes.empty()) return false;
+
+  NumInvokes += Invokes.size();
+  NumUnwinds += Unwinds.size();
+  
+  // TODO: This is not an optimal way to do this.  In particular, this always
+  // inserts setjmp calls into the entries of functions with invoke instructions
+  // even though there are possibly paths through the function that do not
+  // execute any invokes.  In particular, for functions with early exits, e.g.
+  // the 'addMove' method in hexxagon, it would be nice to not have to do the
+  // setjmp stuff on the early exit path.  This requires a bit of dataflow, but
+  // would not be too hard to do.
+
+  // If we have an invoke instruction, insert a setjmp that dominates all
+  // invokes.  After the setjmp, use a cond branch that goes to the original
+  // code path on zero, and to a designated 'catch' block of nonzero.
+  Value *OldJmpBufPtr = 0;
+  if (!Invokes.empty()) {
+    // First thing we need to do is scan the whole function for values that are
+    // live across unwind edges.  Each value that is live across an unwind edge
+    // we spill into a stack location, guaranteeing that there is nothing live
+    // across the unwind edge.  This process also splits all critical edges
+    // coming out of invoke's.
+    splitLiveRangesLiveAcrossInvokes(Invokes);    
+    
+    BasicBlock *EntryBB = F.begin();
+    
+    // Create an alloca for the incoming jump buffer ptr and the new jump buffer
+    // that needs to be restored on all exits from the function.  This is an
+    // alloca because the value needs to be live across invokes.
+    AllocaInst *JmpBuf = 
+      new AllocaInst(JBLinkTy, 0, JumpBufAlign, "jblink", F.begin()->begin());
+    
+    std::vector<Value*> Idx;
+    Idx.push_back(Constant::getNullValue(Type::IntTy));
+    Idx.push_back(ConstantUInt::get(Type::UIntTy, 1));
+    OldJmpBufPtr = new GetElementPtrInst(JmpBuf, Idx, "OldBuf",
+                                         EntryBB->getTerminator());
+
+    // Copy the JBListHead to the alloca.
+    Value *OldBuf = new LoadInst(JBListHead, "oldjmpbufptr", true,
+                                 EntryBB->getTerminator());
+    new StoreInst(OldBuf, OldJmpBufPtr, true, EntryBB->getTerminator());
+    
+    // Add the new jumpbuf to the list.
+    new StoreInst(JmpBuf, JBListHead, true, EntryBB->getTerminator());
+
+    // Create the catch block.  The catch block is basically a big switch
+    // statement that goes to all of the invoke catch blocks.
+    BasicBlock *CatchBB = new BasicBlock("setjmp.catch", &F);
+    
+    // Create an alloca which keeps track of which invoke is currently
+    // executing.  For normal calls it contains zero.
+    AllocaInst *InvokeNum = new AllocaInst(Type::UIntTy, 0, "invokenum",
+                                           EntryBB->begin());
+    new StoreInst(ConstantInt::get(Type::UIntTy, 0), InvokeNum, true,
+                  EntryBB->getTerminator());
+    
+    // Insert a load in the Catch block, and a switch on its value.  By default,
+    // we go to a block that just does an unwind (which is the correct action
+    // for a standard call).
+    BasicBlock *UnwindBB = new BasicBlock("unwindbb", &F);
+    Unwinds.push_back(new UnwindInst(UnwindBB));
+    
+    Value *CatchLoad = new LoadInst(InvokeNum, "invoke.num", true, CatchBB);
+    SwitchInst *CatchSwitch = 
+      new SwitchInst(CatchLoad, UnwindBB, Invokes.size(), CatchBB);
+
+    // Now that things are set up, insert the setjmp call itself.
+    
+    // Split the entry block to insert the conditional branch for the setjmp.
+    BasicBlock *ContBlock = EntryBB->splitBasicBlock(EntryBB->getTerminator(),
+                                                     "setjmp.cont");
+
+    Idx[1] = ConstantUInt::get(Type::UIntTy, 0);
+    Value *JmpBufPtr = new GetElementPtrInst(JmpBuf, Idx, "TheJmpBuf",
+                                             EntryBB->getTerminator());
+    Value *SJRet = new CallInst(SetJmpFn, JmpBufPtr, "sjret",
+                                EntryBB->getTerminator());
+    
+    // Compare the return value to zero.
+    Value *IsNormal = BinaryOperator::createSetEQ(SJRet,
+                                     Constant::getNullValue(SJRet->getType()),
+                                        "notunwind", EntryBB->getTerminator());
+    // Nuke the uncond branch.
+    EntryBB->getTerminator()->eraseFromParent();
+    
+    // Put in a new condbranch in its place.
+    new BranchInst(ContBlock, CatchBB, IsNormal, EntryBB);
+
+    // At this point, we are all set up, rewrite each invoke instruction.
+    for (unsigned i = 0, e = Invokes.size(); i != e; ++i)
+      rewriteExpensiveInvoke(Invokes[i], i+1, InvokeNum, CatchSwitch);
+  }
+
+  // We know that there is at least one unwind.
+  
+  // Create three new blocks, the block to load the jmpbuf ptr and compare
+  // against null, the block to do the longjmp, and the error block for if it
+  // is null.  Add them at the end of the function because they are not hot.
+  BasicBlock *UnwindHandler = new BasicBlock("dounwind", &F);
+  BasicBlock *UnwindBlock = new BasicBlock("unwind", &F);
+  BasicBlock *TermBlock = new BasicBlock("unwinderror", &F);
+
+  // If this function contains an invoke, restore the old jumpbuf ptr.
+  Value *BufPtr;
+  if (OldJmpBufPtr) {
+    // Before the return, insert a copy from the saved value to the new value.
+    BufPtr = new LoadInst(OldJmpBufPtr, "oldjmpbufptr", UnwindHandler);
+    new StoreInst(BufPtr, JBListHead, UnwindHandler);
+  } else {
+    BufPtr = new LoadInst(JBListHead, "ehlist", UnwindHandler);
+  }
+  
+  // Load the JBList, if it's null, then there was no catch!
+  Value *NotNull = BinaryOperator::createSetNE(BufPtr,
+                                      Constant::getNullValue(BufPtr->getType()),
+                                          "notnull", UnwindHandler);
+  new BranchInst(UnwindBlock, TermBlock, NotNull, UnwindHandler);
+  
+  // Create the block to do the longjmp.
+  // Get a pointer to the jmpbuf and longjmp.
+  std::vector<Value*> Idx;
+  Idx.push_back(Constant::getNullValue(Type::IntTy));
+  Idx.push_back(ConstantUInt::get(Type::UIntTy, 0));
+  Idx[0] = new GetElementPtrInst(BufPtr, Idx, "JmpBuf", UnwindBlock);
+  Idx[1] = ConstantInt::get(Type::IntTy, 1);
+  new CallInst(LongJmpFn, Idx, "", UnwindBlock);
+  new UnreachableInst(UnwindBlock);
+  
+  // Set up the term block ("throw without a catch").
+  new UnreachableInst(TermBlock);
+
+  // Insert a new call to write(2, AbortMessage, AbortMessageLength);
+  writeAbortMessage(TermBlock->getTerminator());
+  
+  // Insert a call to abort()
+  (new CallInst(AbortFn, std::vector<Value*>(), "",
+                TermBlock->getTerminator()))->setTailCall();
+    
+  
+  // Replace all unwinds with a branch to the unwind handler.
+  for (unsigned i = 0, e = Unwinds.size(); i != e; ++i) {
+    new BranchInst(UnwindHandler, Unwinds[i]);
+    Unwinds[i]->eraseFromParent();    
+  } 
+  
+  // Finally, for any returns from this function, if this function contains an
+  // invoke, restore the old jmpbuf pointer to its input value.
+  if (OldJmpBufPtr) {
+    for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
+      ReturnInst *R = Returns[i];
+      
+      // Before the return, insert a copy from the saved value to the new value.
+      Value *OldBuf = new LoadInst(OldJmpBufPtr, "oldjmpbufptr", true, R);
+      new StoreInst(OldBuf, JBListHead, true, R);
+    }
+  }
+  
+  return true;
+}
+
+bool LowerInvoke::runOnFunction(Function &F) {
+  if (ExpensiveEHSupport)
+    return insertExpensiveEHSupport(F);
+  else
+    return insertCheapEHSupport(F);
+}
diff --git a/llvm/lib/Transforms/Utils/LowerSelect.cpp b/llvm/lib/Transforms/Utils/LowerSelect.cpp
new file mode 100644
index 00000000000..464d30d0308
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/LowerSelect.cpp
@@ -0,0 +1,104 @@
+//===- LowerSelect.cpp - Transform select insts to branches ---------------===//
+//
+//                     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 pass lowers select instructions into conditional branches for targets
+// that do not have conditional moves or that have not implemented the select
+// instruction yet.
+//
+// Note that this pass could be improved.  In particular it turns every select
+// instruction into a new conditional branch, even though some common cases have
+// select instructions on the same predicate next to each other.  It would be
+// better to use the same branch for the whole group of selects.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/Pass.h"
+#include "llvm/Type.h"
+#include "llvm/ADT/Statistic.h"
+using namespace llvm;
+
+namespace {
+  Statistic<> NumLowered("lowerselect","Number of select instructions lowered");
+
+  /// LowerSelect - Turn select instructions into conditional branches.
+  ///
+  class LowerSelect : public FunctionPass {
+    bool OnlyFP;   // Only lower FP select instructions?
+  public:
+    LowerSelect(bool onlyfp = false) : OnlyFP(onlyfp) {}
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      // This certainly destroys the CFG.
+      // This is a cluster of orthogonal Transforms:	
+      AU.addPreserved<UnifyFunctionExitNodes>();
+      AU.addPreservedID(PromoteMemoryToRegisterID);
+      AU.addPreservedID(LowerSwitchID);
+      AU.addPreservedID(LowerInvokePassID);
+      AU.addPreservedID(LowerAllocationsID);
+    }
+
+    bool runOnFunction(Function &F);
+  };
+
+  RegisterOpt<LowerSelect>
+  X("lowerselect", "Lower select instructions to branches");
+}
+
+// Publically exposed interface to pass...
+const PassInfo *llvm::LowerSelectID = X.getPassInfo();
+//===----------------------------------------------------------------------===//
+// This pass converts SelectInst instructions into conditional branch and PHI
+// instructions.  If the OnlyFP flag is set to true, then only floating point
+// select instructions are lowered.
+//
+FunctionPass *llvm::createLowerSelectPass(bool OnlyFP) {
+  return new LowerSelect(OnlyFP);
+}
+
+
+bool LowerSelect::runOnFunction(Function &F) {
+  bool Changed = false;
+  for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
+    for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
+      if (SelectInst *SI = dyn_cast<SelectInst>(I))
+        if (!OnlyFP || SI->getType()->isFloatingPoint()) {
+          // Split this basic block in half right before the select instruction.
+          BasicBlock *NewCont =
+            BB->splitBasicBlock(I, BB->getName()+".selectcont");
+
+          // Make the true block, and make it branch to the continue block.
+          BasicBlock *NewTrue = new BasicBlock(BB->getName()+".selecttrue",
+                                               BB->getParent(), NewCont);
+          new BranchInst(NewCont, NewTrue);
+
+          // Make the unconditional branch in the incoming block be a
+          // conditional branch on the select predicate.
+          BB->getInstList().erase(BB->getTerminator());
+          new BranchInst(NewTrue, NewCont, SI->getCondition(), BB);
+
+          // Create a new PHI node in the cont block with the entries we need.
+          std::string Name = SI->getName(); SI->setName("");
+          PHINode *PN = new PHINode(SI->getType(), Name, NewCont->begin());
+          PN->addIncoming(SI->getTrueValue(), NewTrue);
+          PN->addIncoming(SI->getFalseValue(), BB);
+
+          // Use the PHI instead of the select.
+          SI->replaceAllUsesWith(PN);
+          NewCont->getInstList().erase(SI);
+
+          Changed = true;
+          break; // This block is done with.
+        }
+    }
+  return Changed;
+}
diff --git a/llvm/lib/Transforms/Utils/LowerSwitch.cpp b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
new file mode 100644
index 00000000000..396b507bbd1
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
@@ -0,0 +1,237 @@
+//===- LowerSwitch.cpp - Eliminate Switch instructions --------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+//
+// The LowerSwitch transformation rewrites switch statements with a sequence of
+// branches, which allows targets to get away with not implementing the switch
+// statement until it is convenient.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
+#include "llvm/Constants.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/Visibility.h"
+#include "llvm/ADT/Statistic.h"
+#include <algorithm>
+#include <iostream>
+using namespace llvm;
+
+namespace {
+  Statistic<> NumLowered("lowerswitch", "Number of SwitchInst's replaced");
+
+  /// LowerSwitch Pass - Replace all SwitchInst instructions with chained branch
+  /// instructions.  Note that this cannot be a BasicBlock pass because it
+  /// modifies the CFG!
+  class VISIBILITY_HIDDEN LowerSwitch : public FunctionPass {
+  public:
+    virtual bool runOnFunction(Function &F);
+    
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      // This is a cluster of orthogonal Transforms	
+      AU.addPreserved<UnifyFunctionExitNodes>();
+      AU.addPreservedID(PromoteMemoryToRegisterID);
+      AU.addPreservedID(LowerSelectID);
+      AU.addPreservedID(LowerInvokePassID);
+      AU.addPreservedID(LowerAllocationsID);
+    }
+        
+    typedef std::pair<Constant*, BasicBlock*> Case;
+    typedef std::vector<Case>::iterator       CaseItr;
+  private:
+    void processSwitchInst(SwitchInst *SI);
+
+    BasicBlock* switchConvert(CaseItr Begin, CaseItr End, Value* Val,
+                              BasicBlock* OrigBlock, BasicBlock* Default);
+    BasicBlock* newLeafBlock(Case& Leaf, Value* Val,
+                             BasicBlock* OrigBlock, BasicBlock* Default);
+  };
+
+  /// The comparison function for sorting the switch case values in the vector.
+  struct CaseCmp {
+    bool operator () (const LowerSwitch::Case& C1,
+                      const LowerSwitch::Case& C2) {
+      if (const ConstantUInt* U1 = dyn_cast<const ConstantUInt>(C1.first))
+        return U1->getValue() < cast<const ConstantUInt>(C2.first)->getValue();
+
+      const ConstantSInt* S1 = dyn_cast<const ConstantSInt>(C1.first);
+      return S1->getValue() < cast<const ConstantSInt>(C2.first)->getValue();
+    }
+  };
+
+  RegisterOpt<LowerSwitch>
+  X("lowerswitch", "Lower SwitchInst's to branches");
+}
+
+// Publically exposed interface to pass...
+const PassInfo *llvm::LowerSwitchID = X.getPassInfo();
+// createLowerSwitchPass - Interface to this file...
+FunctionPass *llvm::createLowerSwitchPass() {
+  return new LowerSwitch();
+}
+
+bool LowerSwitch::runOnFunction(Function &F) {
+  bool Changed = false;
+
+  for (Function::iterator I = F.begin(), E = F.end(); I != E; ) {
+    BasicBlock *Cur = I++; // Advance over block so we don't traverse new blocks
+
+    if (SwitchInst *SI = dyn_cast<SwitchInst>(Cur->getTerminator())) {
+      Changed = true;
+      processSwitchInst(SI);
+    }
+  }
+
+  return Changed;
+}
+
+// operator<< - Used for debugging purposes.
+//
+std::ostream& operator<<(std::ostream &O,
+                         const std::vector<LowerSwitch::Case> &C) {
+  O << "[";
+
+  for (std::vector<LowerSwitch::Case>::const_iterator B = C.begin(),
+         E = C.end(); B != E; ) {
+    O << *B->first;
+    if (++B != E) O << ", ";
+  }
+
+  return O << "]";
+}
+
+// switchConvert - Convert the switch statement into a binary lookup of
+// the case values. The function recursively builds this tree.
+//
+BasicBlock* LowerSwitch::switchConvert(CaseItr Begin, CaseItr End,
+                                       Value* Val, BasicBlock* OrigBlock,
+                                       BasicBlock* Default)
+{
+  unsigned Size = End - Begin;
+
+  if (Size == 1)
+    return newLeafBlock(*Begin, Val, OrigBlock, Default);
+
+  unsigned Mid = Size / 2;
+  std::vector<Case> LHS(Begin, Begin + Mid);
+  DEBUG(std::cerr << "LHS: " << LHS << "\n");
+  std::vector<Case> RHS(Begin + Mid, End);
+  DEBUG(std::cerr << "RHS: " << RHS << "\n");
+
+  Case& Pivot = *(Begin + Mid);
+  DEBUG(std::cerr << "Pivot ==> "
+                  << (int64_t)cast<ConstantInt>(Pivot.first)->getRawValue()
+                  << "\n");
+
+  BasicBlock* LBranch = switchConvert(LHS.begin(), LHS.end(), Val,
+                                      OrigBlock, Default);
+  BasicBlock* RBranch = switchConvert(RHS.begin(), RHS.end(), Val,
+                                      OrigBlock, Default);
+
+  // Create a new node that checks if the value is < pivot. Go to the
+  // left branch if it is and right branch if not.
+  Function* F = OrigBlock->getParent();
+  BasicBlock* NewNode = new BasicBlock("NodeBlock");
+  F->getBasicBlockList().insert(OrigBlock->getNext(), NewNode);
+
+  SetCondInst* Comp = new SetCondInst(Instruction::SetLT, Val, Pivot.first,
+                                      "Pivot");
+  NewNode->getInstList().push_back(Comp);
+  new BranchInst(LBranch, RBranch, Comp, NewNode);
+  return NewNode;
+}
+
+// newLeafBlock - Create a new leaf block for the binary lookup tree. It
+// checks if the switch's value == the case's value. If not, then it
+// jumps to the default branch. At this point in the tree, the value
+// can't be another valid case value, so the jump to the "default" branch
+// is warranted.
+//
+BasicBlock* LowerSwitch::newLeafBlock(Case& Leaf, Value* Val,
+                                      BasicBlock* OrigBlock,
+                                      BasicBlock* Default)
+{
+  Function* F = OrigBlock->getParent();
+  BasicBlock* NewLeaf = new BasicBlock("LeafBlock");
+  F->getBasicBlockList().insert(OrigBlock->getNext(), NewLeaf);
+
+  // Make the seteq instruction...
+  SetCondInst* Comp = new SetCondInst(Instruction::SetEQ, Val,
+                                      Leaf.first, "SwitchLeaf");
+  NewLeaf->getInstList().push_back(Comp);
+
+  // Make the conditional branch...
+  BasicBlock* Succ = Leaf.second;
+  new BranchInst(Succ, Default, Comp, NewLeaf);
+
+  // If there were any PHI nodes in this successor, rewrite one entry
+  // from OrigBlock to come from NewLeaf.
+  for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) {
+    PHINode* PN = cast<PHINode>(I);
+    int BlockIdx = PN->getBasicBlockIndex(OrigBlock);
+    assert(BlockIdx != -1 && "Switch didn't go to this successor??");
+    PN->setIncomingBlock((unsigned)BlockIdx, NewLeaf);
+  }
+
+  return NewLeaf;
+}
+
+// processSwitchInst - Replace the specified switch instruction with a sequence
+// of chained if-then insts in a balanced binary search.
+//
+void LowerSwitch::processSwitchInst(SwitchInst *SI) {
+  BasicBlock *CurBlock = SI->getParent();
+  BasicBlock *OrigBlock = CurBlock;
+  Function *F = CurBlock->getParent();
+  Value *Val = SI->getOperand(0);  // The value we are switching on...
+  BasicBlock* Default = SI->getDefaultDest();
+
+  // If there is only the default destination, don't bother with the code below.
+  if (SI->getNumOperands() == 2) {
+    new BranchInst(SI->getDefaultDest(), CurBlock);
+    CurBlock->getInstList().erase(SI);
+    return;
+  }
+
+  // Create a new, empty default block so that the new hierarchy of
+  // if-then statements go to this and the PHI nodes are happy.
+  BasicBlock* NewDefault = new BasicBlock("NewDefault");
+  F->getBasicBlockList().insert(Default, NewDefault);
+
+  new BranchInst(Default, NewDefault);
+
+  // If there is an entry in any PHI nodes for the default edge, make sure
+  // to update them as well.
+  for (BasicBlock::iterator I = Default->begin(); isa<PHINode>(I); ++I) {
+    PHINode *PN = cast<PHINode>(I);
+    int BlockIdx = PN->getBasicBlockIndex(OrigBlock);
+    assert(BlockIdx != -1 && "Switch didn't go to this successor??");
+    PN->setIncomingBlock((unsigned)BlockIdx, NewDefault);
+  }
+
+  std::vector<Case> Cases;
+
+  // Expand comparisons for all of the non-default cases...
+  for (unsigned i = 1; i < SI->getNumSuccessors(); ++i)
+    Cases.push_back(Case(SI->getSuccessorValue(i), SI->getSuccessor(i)));
+
+  std::sort(Cases.begin(), Cases.end(), CaseCmp());
+  DEBUG(std::cerr << "Cases: " << Cases << "\n");
+  BasicBlock* SwitchBlock = switchConvert(Cases.begin(), Cases.end(), Val,
+                                          OrigBlock, NewDefault);
+
+  // Branch to our shiny new if-then stuff...
+  new BranchInst(SwitchBlock, OrigBlock);
+
+  // We are now done with the switch instruction, delete it.
+  CurBlock->getInstList().erase(SI);
+}
diff --git a/llvm/lib/Transforms/Utils/Mem2Reg.cpp b/llvm/lib/Transforms/Utils/Mem2Reg.cpp
new file mode 100644
index 00000000000..d1b2c50796e
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/Mem2Reg.cpp
@@ -0,0 +1,91 @@
+//===- Mem2Reg.cpp - The -mem2reg pass, a wrapper around the Utils lib ----===//
+//
+//                     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 pass is a simple pass wrapper around the PromoteMemToReg function call
+// exposed by the Utils library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/PromoteMemToReg.h"
+#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Instructions.h"
+#include "llvm/Function.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/Visibility.h"
+using namespace llvm;
+
+namespace {
+  Statistic<> NumPromoted("mem2reg", "Number of alloca's promoted");
+
+  struct VISIBILITY_HIDDEN PromotePass : public FunctionPass {
+    // runOnFunction - To run this pass, first we calculate the alloca
+    // instructions that are safe for promotion, then we promote each one.
+    //
+    virtual bool runOnFunction(Function &F);
+
+    // getAnalysisUsage - We need dominance frontiers
+    //
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addRequired<DominatorTree>();
+      AU.addRequired<DominanceFrontier>();
+      AU.addRequired<TargetData>();
+      AU.setPreservesCFG();
+      // This is a cluster of orthogonal Transforms	
+      AU.addPreserved<UnifyFunctionExitNodes>();
+      AU.addPreservedID(LowerSelectID);
+      AU.addPreservedID(LowerSwitchID);
+      AU.addPreservedID(LowerInvokePassID);
+      AU.addPreservedID(LowerAllocationsID);
+    }
+  };
+
+  RegisterOpt<PromotePass> X("mem2reg", "Promote Memory to Register");
+}  // end of anonymous namespace
+
+bool PromotePass::runOnFunction(Function &F) {
+  std::vector<AllocaInst*> Allocas;
+  const TargetData &TD = getAnalysis<TargetData>();
+
+  BasicBlock &BB = F.getEntryBlock();  // Get the entry node for the function
+
+  bool Changed  = false;
+
+  DominatorTree     &DT = getAnalysis<DominatorTree>();
+  DominanceFrontier &DF = getAnalysis<DominanceFrontier>();
+
+  while (1) {
+    Allocas.clear();
+
+    // Find allocas that are safe to promote, by looking at all instructions in
+    // the entry node
+    for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I)
+      if (AllocaInst *AI = dyn_cast<AllocaInst>(I))       // Is it an alloca?
+        if (isAllocaPromotable(AI, TD))
+          Allocas.push_back(AI);
+
+    if (Allocas.empty()) break;
+
+    PromoteMemToReg(Allocas, DT, DF, TD);
+    NumPromoted += Allocas.size();
+    Changed = true;
+  }
+
+  return Changed;
+}
+
+// Publically exposed interface to pass...
+const PassInfo *llvm::PromoteMemoryToRegisterID = X.getPassInfo();
+// createPromoteMemoryToRegister - Provide an entry point to create this pass.
+//
+FunctionPass *llvm::createPromoteMemoryToRegisterPass() {
+  return new PromotePass();
+}