MFC 261991:

Upgrade our copy of llvm/clang to 3.4 release.  This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3.  The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC 262121 (by emaste):

Update lldb for clang/llvm 3.4 import

This commit largely restores the lldb source to the upstream r196259
snapshot with the addition of threaded inferior support and a few bug
fixes.

Specific upstream lldb revisions restored include:
   SVN      git
  181387  779e6ac
  181703  7bef4e2
  182099  b31044e
  182650  f2dcf35
  182683  0d91b80
  183862  15c1774
  183929  99447a6
  184177  0b2934b
  184948  4dc3761
  184954  007e7bc
  186990  eebd175

Sponsored by:	DARPA, AFRL

MFC 262186 (by emaste):

Fix mismerge in r262121

A break statement was lost in the merge.  The error had no functional
impact, but restore it to reduce the diff against upstream.

MFC 262303:

Pull in r197521 from upstream clang trunk (by rdivacky):

  Use the integrated assembler by default on FreeBSD/ppc and ppc64.

Requested by:	jhibbits

MFC 262611:

Pull in r196874 from upstream llvm trunk:

  Fix a crash that occurs when PWD is invalid.

  MCJIT needs to be able to run in hostile environments, even when PWD
  is invalid. There's no need to crash MCJIT in this case.

  The obvious fix is to simply leave MCContext's CompilationDir empty
  when PWD can't be determined. This way, MCJIT clients,
  and other clients that link with LLVM don't need a valid working directory.

  If we do want to guarantee valid CompilationDir, that should be done
  only for clients of getCompilationDir(). This is as simple as checking
  for an empty string.

  The only current use of getCompilationDir is EmitGenDwarfInfo, which
  won't conceivably run with an invalid working dir. However, in the
  purely hypothetically and untestable case that this happens, the
  AT_comp_dir will be omitted from the compilation_unit DIE.

This should help fix assertions occurring with ports-mgmt/tinderbox,
when it is using jails, and sometimes invalidates clang's current
working directory.

Reported by:	decke

MFC 262809:

Pull in r203007 from upstream clang trunk:

  Don't produce an alias between destructors with different calling conventions.

  Fixes pr19007.

(Please note that is an LLVM PR identifier, not a FreeBSD one.)

This should fix Firefox and/or libxul crashes (due to problems with
regparm/stdcall calling conventions) on i386.

Reported by:	multiple users on freebsd-current
PR:		bin/187103

MFC 263048:

Repair recognition of "CC" as an alias for the C++ compiler, since it
was silently broken by upstream for a Windows-specific use-case.

Apparently some versions of CMake still rely on this archaic feature...

Reported by:	rakuco

MFC 263049:

Garbage collect the old way of adding the libstdc++ include directories
in clang's InitHeaderSearch.cpp.  This has been superseded by David
Chisnall's commit in r255321.

Moreover, if libc++ is used, the libstdc++ include directories should
not be in the search path at all.  These directories are now only used
if you pass -stdlib=libstdc++.

1 files changed, 519 insertions, 645 deletions

diff --git a/contrib/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp b/contrib/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp
index 81a54d7..4224ae2 100644
--- a/contrib/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp
+++ b/contrib/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp
@@ -9,767 +9,641 @@
 //
 // This pass identifies loops where we can generate the PPC branch instructions
 // that decrement and test the count register (CTR) (bdnz and friends).
-// This pass is based on the HexagonHardwareLoops pass.
 //
 // The pattern that defines the induction variable can changed depending on
 // prior optimizations.  For example, the IndVarSimplify phase run by 'opt'
 // normalizes induction variables, and the Loop Strength Reduction pass
 // run by 'llc' may also make changes to the induction variable.
-// The pattern detected by this phase is due to running Strength Reduction.
 //
 // Criteria for CTR loops:
 //  - Countable loops (w/ ind. var for a trip count)
-//  - Assumes loops are normalized by IndVarSimplify
 //  - Try inner-most loops first
 //  - No nested CTR loops.
 //  - No function calls in loops.
 //
-//  Note: As with unconverted loops, PPCBranchSelector must be run after this
-//  pass in order to convert long-displacement jumps into jump pairs.
-//
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "ctrloops"
-#include "PPC.h"
-#include "MCTargetDesc/PPCPredicates.h"
-#include "PPCTargetMachine.h"
-#include "llvm/ADT/DenseMap.h"
+
+#include "llvm/Transforms/Scalar.h"
 #include "llvm/ADT/Statistic.h"
-#include "llvm/CodeGen/MachineDominators.h"
-#include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "llvm/CodeGen/MachineLoopInfo.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/CodeGen/RegisterScavenging.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/ScalarEvolutionExpander.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/InlineAsm.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
 #include "llvm/PassSupport.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ValueHandle.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Utils/LoopUtils.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "PPCTargetMachine.h"
+#include "PPC.h"
+
+#ifndef NDEBUG
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#endif
+
 #include <algorithm>
+#include <vector>
 
 using namespace llvm;
 
+#ifndef NDEBUG
+static cl::opt<int> CTRLoopLimit("ppc-max-ctrloop", cl::Hidden, cl::init(-1));
+#endif
+
 STATISTIC(NumCTRLoops, "Number of loops converted to CTR loops");
 
 namespace llvm {
   void initializePPCCTRLoopsPass(PassRegistry&);
+#ifndef NDEBUG
+  void initializePPCCTRLoopsVerifyPass(PassRegistry&);
+#endif
 }
 
 namespace {
-  class CountValue;
-  struct PPCCTRLoops : public MachineFunctionPass {
-    MachineLoopInfo       *MLI;
-    MachineRegisterInfo   *MRI;
-    const TargetInstrInfo *TII;
+  struct PPCCTRLoops : public FunctionPass {
+
+#ifndef NDEBUG
+    static int Counter;
+#endif
 
   public:
-    static char ID;   // Pass identification, replacement for typeid
+    static char ID;
 
-    PPCCTRLoops() : MachineFunctionPass(ID) {
+    PPCCTRLoops() : FunctionPass(ID), TM(0) {
+      initializePPCCTRLoopsPass(*PassRegistry::getPassRegistry());
+    }
+    PPCCTRLoops(PPCTargetMachine &TM) : FunctionPass(ID), TM(&TM) {
       initializePPCCTRLoopsPass(*PassRegistry::getPassRegistry());
     }
 
-    virtual bool runOnMachineFunction(MachineFunction &MF);
-
-    const char *getPassName() const { return "PPC CTR Loops"; }
+    virtual bool runOnFunction(Function &F);
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.setPreservesCFG();
-      AU.addRequired<MachineDominatorTree>();
-      AU.addPreserved<MachineDominatorTree>();
-      AU.addRequired<MachineLoopInfo>();
-      AU.addPreserved<MachineLoopInfo>();
-      MachineFunctionPass::getAnalysisUsage(AU);
+      AU.addRequired<LoopInfo>();
+      AU.addPreserved<LoopInfo>();
+      AU.addRequired<DominatorTree>();
+      AU.addPreserved<DominatorTree>();
+      AU.addRequired<ScalarEvolution>();
     }
 
   private:
-    /// getCanonicalInductionVariable - Check to see if the loop has a canonical
-    /// induction variable.
-    /// Should be defined in MachineLoop. Based upon version in class Loop.
-    void getCanonicalInductionVariable(MachineLoop *L,
-                              SmallVector<MachineInstr *, 4> &IVars,
-                              SmallVector<MachineInstr *, 4> &IOps) const;
-
-    /// getTripCount - Return a loop-invariant LLVM register indicating the
-    /// number of times the loop will be executed.  If the trip-count cannot
-    /// be determined, this return null.
-    CountValue *getTripCount(MachineLoop *L,
-                             SmallVector<MachineInstr *, 2> &OldInsts) const;
-
-    /// isInductionOperation - Return true if the instruction matches the
-    /// pattern for an opertion that defines an induction variable.
-    bool isInductionOperation(const MachineInstr *MI, unsigned IVReg) const;
-
-    /// isInvalidOperation - Return true if the instruction is not valid within
-    /// a CTR loop.
-    bool isInvalidLoopOperation(const MachineInstr *MI) const;
-
-    /// containsInavlidInstruction - Return true if the loop contains an
-    /// instruction that inhibits using the CTR loop.
-    bool containsInvalidInstruction(MachineLoop *L) const;
-
-    /// converToCTRLoop - Given a loop, check if we can convert it to a
-    /// CTR loop.  If so, then perform the conversion and return true.
-    bool convertToCTRLoop(MachineLoop *L);
-
-    /// isDead - Return true if the instruction is now dead.
-    bool isDead(const MachineInstr *MI,
-                SmallVector<MachineInstr *, 1> &DeadPhis) const;
-
-    /// removeIfDead - Remove the instruction if it is now dead.
-    void removeIfDead(MachineInstr *MI);
+    bool mightUseCTR(const Triple &TT, BasicBlock *BB);
+    bool convertToCTRLoop(Loop *L);
+
+  private:
+    PPCTargetMachine *TM;
+    LoopInfo *LI;
+    ScalarEvolution *SE;
+    DataLayout *TD;
+    DominatorTree *DT;
+    const TargetLibraryInfo *LibInfo;
   };
 
   char PPCCTRLoops::ID = 0;
+#ifndef NDEBUG
+  int PPCCTRLoops::Counter = 0;
+#endif
 
-
-  // CountValue class - Abstraction for a trip count of a loop. A
-  // smaller vesrsion of the MachineOperand class without the concerns
-  // of changing the operand representation.
-  class CountValue {
+#ifndef NDEBUG
+  struct PPCCTRLoopsVerify : public MachineFunctionPass {
   public:
-    enum CountValueType {
-      CV_Register,
-      CV_Immediate
-    };
-  private:
-    CountValueType Kind;
-    union Values {
-      unsigned RegNum;
-      int64_t ImmVal;
-      Values(unsigned r) : RegNum(r) {}
-      Values(int64_t i) : ImmVal(i) {}
-    } Contents;
-    bool isNegative;
+    static char ID;
 
-  public:
-    CountValue(unsigned r, bool neg) : Kind(CV_Register), Contents(r),
-                                       isNegative(neg) {}
-    explicit CountValue(int64_t i) : Kind(CV_Immediate), Contents(i),
-                                     isNegative(i < 0) {}
-    CountValueType getType() const { return Kind; }
-    bool isReg() const { return Kind == CV_Register; }
-    bool isImm() const { return Kind == CV_Immediate; }
-    bool isNeg() const { return isNegative; }
-
-    unsigned getReg() const {
-      assert(isReg() && "Wrong CountValue accessor");
-      return Contents.RegNum;
-    }
-    void setReg(unsigned Val) {
-      Contents.RegNum = Val;
-    }
-    int64_t getImm() const {
-      assert(isImm() && "Wrong CountValue accessor");
-      if (isNegative) {
-        return -Contents.ImmVal;
-      }
-      return Contents.ImmVal;
-    }
-    void setImm(int64_t Val) {
-      Contents.ImmVal = Val;
+    PPCCTRLoopsVerify() : MachineFunctionPass(ID) {
+      initializePPCCTRLoopsVerifyPass(*PassRegistry::getPassRegistry());
     }
 
-    void print(raw_ostream &OS, const TargetMachine *TM = 0) const {
-      if (isReg()) { OS << PrintReg(getReg()); }
-      if (isImm()) { OS << getImm(); }
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addRequired<MachineDominatorTree>();
+      MachineFunctionPass::getAnalysisUsage(AU);
     }
+
+    virtual bool runOnMachineFunction(MachineFunction &MF);
+
+  private:
+    MachineDominatorTree *MDT;
   };
+
+  char PPCCTRLoopsVerify::ID = 0;
+#endif // NDEBUG
 } // end anonymous namespace
 
 INITIALIZE_PASS_BEGIN(PPCCTRLoops, "ppc-ctr-loops", "PowerPC CTR Loops",
                       false, false)
-INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
-INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_DEPENDENCY(LoopInfo)
+INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
 INITIALIZE_PASS_END(PPCCTRLoops, "ppc-ctr-loops", "PowerPC CTR Loops",
                     false, false)
 
-/// isCompareEquals - Returns true if the instruction is a compare equals
-/// instruction with an immediate operand.
-static bool isCompareEqualsImm(const MachineInstr *MI, bool &SignedCmp,
-                               bool &Int64Cmp) {
-  if (MI->getOpcode() == PPC::CMPWI) {
-    SignedCmp = true;
-    Int64Cmp = false;
-    return true;
-  } else if (MI->getOpcode() == PPC::CMPDI) {
-    SignedCmp = true;
-    Int64Cmp = true;
-    return true;
-  } else if (MI->getOpcode() == PPC::CMPLWI) {
-    SignedCmp = false;
-    Int64Cmp = false;
-    return true;
-  } else if (MI->getOpcode() == PPC::CMPLDI) {
-    SignedCmp = false;
-    Int64Cmp = true;
-    return true;
-  }
-
-  return false;
+FunctionPass *llvm::createPPCCTRLoops(PPCTargetMachine &TM) {
+  return new PPCCTRLoops(TM);
 }
 
+#ifndef NDEBUG
+INITIALIZE_PASS_BEGIN(PPCCTRLoopsVerify, "ppc-ctr-loops-verify",
+                      "PowerPC CTR Loops Verify", false, false)
+INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
+INITIALIZE_PASS_END(PPCCTRLoopsVerify, "ppc-ctr-loops-verify",
+                    "PowerPC CTR Loops Verify", false, false)
 
-/// createPPCCTRLoops - Factory for creating
-/// the CTR loop phase.
-FunctionPass *llvm::createPPCCTRLoops() {
-  return new PPCCTRLoops();
+FunctionPass *llvm::createPPCCTRLoopsVerify() {
+  return new PPCCTRLoopsVerify();
 }
+#endif // NDEBUG
 
+bool PPCCTRLoops::runOnFunction(Function &F) {
+  LI = &getAnalysis<LoopInfo>();
+  SE = &getAnalysis<ScalarEvolution>();
+  DT = &getAnalysis<DominatorTree>();
+  TD = getAnalysisIfAvailable<DataLayout>();
+  LibInfo = getAnalysisIfAvailable<TargetLibraryInfo>();
 
-bool PPCCTRLoops::runOnMachineFunction(MachineFunction &MF) {
-  DEBUG(dbgs() << "********* PPC CTR Loops *********\n");
-
-  bool Changed = false;
+  bool MadeChange = false;
 
-  // get the loop information
-  MLI = &getAnalysis<MachineLoopInfo>();
-  // get the register information
-  MRI = &MF.getRegInfo();
-  // the target specific instructio info.
-  TII = MF.getTarget().getInstrInfo();
-
-  for (MachineLoopInfo::iterator I = MLI->begin(), E = MLI->end();
+  for (LoopInfo::iterator I = LI->begin(), E = LI->end();
        I != E; ++I) {
-    MachineLoop *L = *I;
-    if (!L->getParentLoop()) {
-      Changed |= convertToCTRLoop(L);
-    }
+    Loop *L = *I;
+    if (!L->getParentLoop())
+      MadeChange |= convertToCTRLoop(L);
   }
 
-  return Changed;
+  return MadeChange;
 }
 
-/// getCanonicalInductionVariable - Check to see if the loop has a canonical
-/// induction variable. We check for a simple recurrence pattern - an
-/// integer recurrence that decrements by one each time through the loop and
-/// ends at zero.  If so, return the phi node that corresponds to it.
-///
-/// Based upon the similar code in LoopInfo except this code is specific to
-/// the machine.
-/// This method assumes that the IndVarSimplify pass has been run by 'opt'.
-///
-void
-PPCCTRLoops::getCanonicalInductionVariable(MachineLoop *L,
-                                  SmallVector<MachineInstr *, 4> &IVars,
-                                  SmallVector<MachineInstr *, 4> &IOps) const {
-  MachineBasicBlock *TopMBB = L->getTopBlock();
-  MachineBasicBlock::pred_iterator PI = TopMBB->pred_begin();
-  assert(PI != TopMBB->pred_end() &&
-         "Loop must have more than one incoming edge!");
-  MachineBasicBlock *Backedge = *PI++;
-  if (PI == TopMBB->pred_end()) return;  // dead loop
-  MachineBasicBlock *Incoming = *PI++;
-  if (PI != TopMBB->pred_end()) return;  // multiple backedges?
-
-  // make sure there is one incoming and one backedge and determine which
-  // is which.
-  if (L->contains(Incoming)) {
-    if (L->contains(Backedge))
-      return;
-    std::swap(Incoming, Backedge);
-  } else if (!L->contains(Backedge))
-    return;
-
-  // Loop over all of the PHI nodes, looking for a canonical induction variable:
-  //   - The PHI node is "reg1 = PHI reg2, BB1, reg3, BB2".
-  //   - The recurrence comes from the backedge.
-  //   - the definition is an induction operatio.n
-  for (MachineBasicBlock::iterator I = TopMBB->begin(), E = TopMBB->end();
-       I != E && I->isPHI(); ++I) {
-    MachineInstr *MPhi = &*I;
-    unsigned DefReg = MPhi->getOperand(0).getReg();
-    for (unsigned i = 1; i != MPhi->getNumOperands(); i += 2) {
-      // Check each operand for the value from the backedge.
-      MachineBasicBlock *MBB = MPhi->getOperand(i+1).getMBB();
-      if (L->contains(MBB)) { // operands comes from the backedge
-        // Check if the definition is an induction operation.
-        MachineInstr *DI = MRI->getVRegDef(MPhi->getOperand(i).getReg());
-        if (isInductionOperation(DI, DefReg)) {
-          IOps.push_back(DI);
-          IVars.push_back(MPhi);
+bool PPCCTRLoops::mightUseCTR(const Triple &TT, BasicBlock *BB) {
+  for (BasicBlock::iterator J = BB->begin(), JE = BB->end();
+       J != JE; ++J) {
+    if (CallInst *CI = dyn_cast<CallInst>(J)) {
+      if (InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledValue())) {
+        // Inline ASM is okay, unless it clobbers the ctr register.
+        InlineAsm::ConstraintInfoVector CIV = IA->ParseConstraints();
+        for (unsigned i = 0, ie = CIV.size(); i < ie; ++i) {
+          InlineAsm::ConstraintInfo &C = CIV[i];
+          if (C.Type != InlineAsm::isInput)
+            for (unsigned j = 0, je = C.Codes.size(); j < je; ++j)
+              if (StringRef(C.Codes[j]).equals_lower("{ctr}"))
+                return true;
         }
-      }
-    }
-  }
-  return;
-}
 
-/// getTripCount - Return a loop-invariant LLVM value indicating the
-/// number of times the loop will be executed.  The trip count can
-/// be either a register or a constant value.  If the trip-count
-/// cannot be determined, this returns null.
-///
-/// We find the trip count from the phi instruction that defines the
-/// induction variable.  We follow the links to the CMP instruction
-/// to get the trip count.
-///
-/// Based upon getTripCount in LoopInfo.
-///
-CountValue *PPCCTRLoops::getTripCount(MachineLoop *L,
-                           SmallVector<MachineInstr *, 2> &OldInsts) const {
-  MachineBasicBlock *LastMBB = L->getExitingBlock();
-  // Don't generate a CTR loop if the loop has more than one exit.
-  if (LastMBB == 0)
-    return 0;
-
-  MachineBasicBlock::iterator LastI = LastMBB->getFirstTerminator();
-  if (LastI->getOpcode() != PPC::BCC)
-    return 0;
-
-  // We need to make sure that this compare is defining the condition
-  // register actually used by the terminating branch.
-
-  unsigned PredReg = LastI->getOperand(1).getReg();
-  DEBUG(dbgs() << "Examining loop with first terminator: " << *LastI);
-
-  unsigned PredCond = LastI->getOperand(0).getImm();
-  if (PredCond != PPC::PRED_EQ && PredCond != PPC::PRED_NE)
-    return 0;
-
-  // Check that the loop has a induction variable.
-  SmallVector<MachineInstr *, 4> IVars, IOps;
-  getCanonicalInductionVariable(L, IVars, IOps);
-  for (unsigned i = 0; i < IVars.size(); ++i) {
-    MachineInstr *IOp = IOps[i];
-    MachineInstr *IV_Inst = IVars[i];
-
-    // Canonical loops will end with a 'cmpwi/cmpdi cr, IV, Imm',
-    //  if Imm is 0, get the count from the PHI opnd
-    //  if Imm is -M, than M is the count
-    //  Otherwise, Imm is the count
-    MachineOperand *IV_Opnd;
-    const MachineOperand *InitialValue;
-    if (!L->contains(IV_Inst->getOperand(2).getMBB())) {
-      InitialValue = &IV_Inst->getOperand(1);
-      IV_Opnd = &IV_Inst->getOperand(3);
-    } else {
-      InitialValue = &IV_Inst->getOperand(3);
-      IV_Opnd = &IV_Inst->getOperand(1);
-    }
+        continue;
+      }
 
-    DEBUG(dbgs() << "Considering:\n");
-    DEBUG(dbgs() << "  induction operation: " << *IOp);
-    DEBUG(dbgs() << "  induction variable: " << *IV_Inst);
-    DEBUG(dbgs() << "  initial value: " << *InitialValue << "\n");
-  
-    // Look for the cmp instruction to determine if we
-    // can get a useful trip count.  The trip count can
-    // be either a register or an immediate.  The location
-    // of the value depends upon the type (reg or imm).
-    for (MachineRegisterInfo::reg_iterator
-         RI = MRI->reg_begin(IV_Opnd->getReg()), RE = MRI->reg_end();
-         RI != RE; ++RI) {
-      IV_Opnd = &RI.getOperand();
-      bool SignedCmp, Int64Cmp;
-      MachineInstr *MI = IV_Opnd->getParent();
-      if (L->contains(MI) && isCompareEqualsImm(MI, SignedCmp, Int64Cmp) &&
-          MI->getOperand(0).getReg() == PredReg) {
-
-        OldInsts.push_back(MI);
-        OldInsts.push_back(IOp);
- 
-        DEBUG(dbgs() << "  compare: " << *MI);
- 
-        const MachineOperand &MO = MI->getOperand(2);
-        assert(MO.isImm() && "IV Cmp Operand should be an immediate");
-
-        int64_t ImmVal;
-        if (SignedCmp)
-          ImmVal = (short) MO.getImm();
-        else
-          ImmVal = MO.getImm();
-  
-        const MachineInstr *IV_DefInstr = MRI->getVRegDef(IV_Opnd->getReg());
-        assert(L->contains(IV_DefInstr->getParent()) &&
-               "IV definition should occurs in loop");
-        int64_t iv_value = (short) IV_DefInstr->getOperand(2).getImm();
-  
-        assert(InitialValue->isReg() && "Expecting register for init value");
-        unsigned InitialValueReg = InitialValue->getReg();
-  
-        MachineInstr *DefInstr = MRI->getVRegDef(InitialValueReg);
-  
-        // Here we need to look for an immediate load (an li or lis/ori pair).
-        if (DefInstr && (DefInstr->getOpcode() == PPC::ORI8 ||
-                         DefInstr->getOpcode() == PPC::ORI)) {
-          int64_t start = DefInstr->getOperand(2).getImm();
-          MachineInstr *DefInstr2 =
-            MRI->getVRegDef(DefInstr->getOperand(1).getReg());
-          if (DefInstr2 && (DefInstr2->getOpcode() == PPC::LIS8 ||
-                            DefInstr2->getOpcode() == PPC::LIS)) {
-            DEBUG(dbgs() << "  initial constant: " << *DefInstr);
-            DEBUG(dbgs() << "  initial constant: " << *DefInstr2);
-
-            start |= int64_t(short(DefInstr2->getOperand(1).getImm())) << 16;
-  
-            int64_t count = ImmVal - start;
-            if ((count % iv_value) != 0) {
-              return 0;
-            }
-
-            OldInsts.push_back(DefInstr);
-            OldInsts.push_back(DefInstr2);
-
-            // count/iv_value, the trip count, should be positive here. If it
-            // is negative, that indicates that the counter will wrap.
-            if (Int64Cmp)
-              return new CountValue(count/iv_value);
+      if (!TM)
+        return true;
+      const TargetLowering *TLI = TM->getTargetLowering();
+
+      if (Function *F = CI->getCalledFunction()) {
+        // Most intrinsics don't become function calls, but some might.
+        // sin, cos, exp and log are always calls.
+        unsigned Opcode;
+        if (F->getIntrinsicID() != Intrinsic::not_intrinsic) {
+          switch (F->getIntrinsicID()) {
+          default: continue;
+
+// VisualStudio defines setjmp as _setjmp
+#if defined(_MSC_VER) && defined(setjmp) && \
+                       !defined(setjmp_undefined_for_msvc)
+#  pragma push_macro("setjmp")
+#  undef setjmp
+#  define setjmp_undefined_for_msvc
+#endif
+
+          case Intrinsic::setjmp:
+
+#if defined(_MSC_VER) && defined(setjmp_undefined_for_msvc)
+ // let's return it to _setjmp state
+#  pragma pop_macro("setjmp")
+#  undef setjmp_undefined_for_msvc
+#endif
+
+          case Intrinsic::longjmp:
+
+          // Exclude eh_sjlj_setjmp; we don't need to exclude eh_sjlj_longjmp
+          // because, although it does clobber the counter register, the
+          // control can't then return to inside the loop unless there is also
+          // an eh_sjlj_setjmp.
+          case Intrinsic::eh_sjlj_setjmp:
+
+          case Intrinsic::memcpy:
+          case Intrinsic::memmove:
+          case Intrinsic::memset:
+          case Intrinsic::powi:
+          case Intrinsic::log:
+          case Intrinsic::log2:
+          case Intrinsic::log10:
+          case Intrinsic::exp:
+          case Intrinsic::exp2:
+          case Intrinsic::pow:
+          case Intrinsic::sin:
+          case Intrinsic::cos:
+            return true;
+          case Intrinsic::copysign:
+            if (CI->getArgOperand(0)->getType()->getScalarType()->
+                isPPC_FP128Ty())
+              return true;
             else
-              return new CountValue(uint32_t(count/iv_value));
-          }
-        } else if (DefInstr && (DefInstr->getOpcode() == PPC::LI8 ||
-                                DefInstr->getOpcode() == PPC::LI)) {
-          DEBUG(dbgs() << "  initial constant: " << *DefInstr);
-
-          int64_t count = ImmVal -
-            int64_t(short(DefInstr->getOperand(1).getImm()));
-          if ((count % iv_value) != 0) {
-            return 0;
+              continue; // ISD::FCOPYSIGN is never a library call.
+          case Intrinsic::sqrt:      Opcode = ISD::FSQRT;      break;
+          case Intrinsic::floor:     Opcode = ISD::FFLOOR;     break;
+          case Intrinsic::ceil:      Opcode = ISD::FCEIL;      break;
+          case Intrinsic::trunc:     Opcode = ISD::FTRUNC;     break;
+          case Intrinsic::rint:      Opcode = ISD::FRINT;      break;
+          case Intrinsic::nearbyint: Opcode = ISD::FNEARBYINT; break;
+          case Intrinsic::round:     Opcode = ISD::FROUND;     break;
           }
+        }
 
-          OldInsts.push_back(DefInstr);
-
-          if (Int64Cmp)
-            return new CountValue(count/iv_value);
-          else
-            return new CountValue(uint32_t(count/iv_value));
-        } else if (iv_value == 1 || iv_value == -1) {
-          // We can't determine a constant starting value.
-          if (ImmVal == 0) {
-            return new CountValue(InitialValueReg, iv_value > 0);
+        // PowerPC does not use [US]DIVREM or other library calls for
+        // operations on regular types which are not otherwise library calls
+        // (i.e. soft float or atomics). If adapting for targets that do,
+        // additional care is required here.
+
+        LibFunc::Func Func;
+        if (!F->hasLocalLinkage() && F->hasName() && LibInfo &&
+            LibInfo->getLibFunc(F->getName(), Func) &&
+            LibInfo->hasOptimizedCodeGen(Func)) {
+          // Non-read-only functions are never treated as intrinsics.
+          if (!CI->onlyReadsMemory())
+            return true;
+
+          // Conversion happens only for FP calls.
+          if (!CI->getArgOperand(0)->getType()->isFloatingPointTy())
+            return true;
+
+          switch (Func) {
+          default: return true;
+          case LibFunc::copysign:
+          case LibFunc::copysignf:
+            continue; // ISD::FCOPYSIGN is never a library call.
+          case LibFunc::copysignl:
+            return true;
+          case LibFunc::fabs:
+          case LibFunc::fabsf:
+          case LibFunc::fabsl:
+            continue; // ISD::FABS is never a library call.
+          case LibFunc::sqrt:
+          case LibFunc::sqrtf:
+          case LibFunc::sqrtl:
+            Opcode = ISD::FSQRT; break;
+          case LibFunc::floor:
+          case LibFunc::floorf:
+          case LibFunc::floorl:
+            Opcode = ISD::FFLOOR; break;
+          case LibFunc::nearbyint:
+          case LibFunc::nearbyintf:
+          case LibFunc::nearbyintl:
+            Opcode = ISD::FNEARBYINT; break;
+          case LibFunc::ceil:
+          case LibFunc::ceilf:
+          case LibFunc::ceill:
+            Opcode = ISD::FCEIL; break;
+          case LibFunc::rint:
+          case LibFunc::rintf:
+          case LibFunc::rintl:
+            Opcode = ISD::FRINT; break;
+          case LibFunc::round:
+          case LibFunc::roundf:
+          case LibFunc::roundl:
+            Opcode = ISD::FROUND; break;
+          case LibFunc::trunc:
+          case LibFunc::truncf:
+          case LibFunc::truncl:
+            Opcode = ISD::FTRUNC; break;
           }
-          // FIXME: handle non-zero end value.
+
+          MVT VTy =
+            TLI->getSimpleValueType(CI->getArgOperand(0)->getType(), true);
+          if (VTy == MVT::Other)
+            return true;
+          
+          if (TLI->isOperationLegalOrCustom(Opcode, VTy))
+            continue;
+          else if (VTy.isVector() &&
+                   TLI->isOperationLegalOrCustom(Opcode, VTy.getScalarType()))
+            continue;
+
+          return true;
         }
-        // FIXME: handle non-unit increments (we might not want to introduce
-        // division but we can handle some 2^n cases with shifts).
-  
       }
-    }
-  }
-  return 0;
-}
-
-/// isInductionOperation - return true if the operation is matches the
-/// pattern that defines an induction variable:
-///    addi iv, c
-///
-bool
-PPCCTRLoops::isInductionOperation(const MachineInstr *MI,
-                                           unsigned IVReg) const {
-  return ((MI->getOpcode() == PPC::ADDI || MI->getOpcode() == PPC::ADDI8) &&
-          MI->getOperand(1).isReg() && // could be a frame index instead
-          MI->getOperand(1).getReg() == IVReg);
-}
 
-/// isInvalidOperation - Return true if the operation is invalid within
-/// CTR loop.
-bool
-PPCCTRLoops::isInvalidLoopOperation(const MachineInstr *MI) const {
-
-  // call is not allowed because the callee may use a CTR loop
-  if (MI->getDesc().isCall()) {
-    return true;
-  }
-  // check if the instruction defines a CTR loop register
-  // (this will also catch nested CTR loops)
-  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
-    const MachineOperand &MO = MI->getOperand(i);
-    if (MO.isReg() && MO.isDef() &&
-        (MO.getReg() == PPC::CTR || MO.getReg() == PPC::CTR8)) {
       return true;
-    }
-  }
-  return false;
-}
+    } else if (isa<BinaryOperator>(J) &&
+               J->getType()->getScalarType()->isPPC_FP128Ty()) {
+      // Most operations on ppc_f128 values become calls.
+      return true;
+    } else if (isa<UIToFPInst>(J) || isa<SIToFPInst>(J) ||
+               isa<FPToUIInst>(J) || isa<FPToSIInst>(J)) {
+      CastInst *CI = cast<CastInst>(J);
+      if (CI->getSrcTy()->getScalarType()->isPPC_FP128Ty() ||
+          CI->getDestTy()->getScalarType()->isPPC_FP128Ty() ||
+          (TT.isArch32Bit() &&
+           (CI->getSrcTy()->getScalarType()->isIntegerTy(64) ||
+            CI->getDestTy()->getScalarType()->isIntegerTy(64))
+          ))
+        return true;
+    } else if (TT.isArch32Bit() &&
+               J->getType()->getScalarType()->isIntegerTy(64) &&
+               (J->getOpcode() == Instruction::UDiv ||
+                J->getOpcode() == Instruction::SDiv ||
+                J->getOpcode() == Instruction::URem ||
+                J->getOpcode() == Instruction::SRem)) {
+      return true;
+    } else if (isa<IndirectBrInst>(J) || isa<InvokeInst>(J)) {
+      // On PowerPC, indirect jumps use the counter register.
+      return true;
+    } else if (SwitchInst *SI = dyn_cast<SwitchInst>(J)) {
+      if (!TM)
+        return true;
+      const TargetLowering *TLI = TM->getTargetLowering();
 
-/// containsInvalidInstruction - Return true if the loop contains
-/// an instruction that inhibits the use of the CTR loop function.
-///
-bool PPCCTRLoops::containsInvalidInstruction(MachineLoop *L) const {
-  const std::vector<MachineBasicBlock*> Blocks = L->getBlocks();
-  for (unsigned i = 0, e = Blocks.size(); i != e; ++i) {
-    MachineBasicBlock *MBB = Blocks[i];
-    for (MachineBasicBlock::iterator
-           MII = MBB->begin(), E = MBB->end(); MII != E; ++MII) {
-      const MachineInstr *MI = &*MII;
-      if (isInvalidLoopOperation(MI)) {
+      if (TLI->supportJumpTables() &&
+          SI->getNumCases()+1 >= (unsigned) TLI->getMinimumJumpTableEntries())
         return true;
-      }
     }
   }
+
   return false;
 }
 
-/// isDead returns true if the instruction is dead
-/// (this was essentially copied from DeadMachineInstructionElim::isDead, but
-/// with special cases for inline asm, physical registers and instructions with
-/// side effects removed)
-bool PPCCTRLoops::isDead(const MachineInstr *MI,
-                         SmallVector<MachineInstr *, 1> &DeadPhis) const {
-  // Examine each operand.
-  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
-    const MachineOperand &MO = MI->getOperand(i);
-    if (MO.isReg() && MO.isDef()) {
-      unsigned Reg = MO.getReg();
-      if (!MRI->use_nodbg_empty(Reg)) {
-        // This instruction has users, but if the only user is the phi node for
-        // the parent block, and the only use of that phi node is this
-        // instruction, then this instruction is dead: both it (and the phi
-        // node) can be removed.
-        MachineRegisterInfo::use_iterator I = MRI->use_begin(Reg);
-        if (llvm::next(I) == MRI->use_end() &&
-            I.getOperand().getParent()->isPHI()) {
-          MachineInstr *OnePhi = I.getOperand().getParent();
-
-          for (unsigned j = 0, f = OnePhi->getNumOperands(); j != f; ++j) {
-            const MachineOperand &OPO = OnePhi->getOperand(j);
-            if (OPO.isReg() && OPO.isDef()) {
-              unsigned OPReg = OPO.getReg();
-
-              MachineRegisterInfo::use_iterator nextJ;
-              for (MachineRegisterInfo::use_iterator J = MRI->use_begin(OPReg),
-                   E = MRI->use_end(); J!=E; J=nextJ) {
-                nextJ = llvm::next(J);
-                MachineOperand& Use = J.getOperand();
-                MachineInstr *UseMI = Use.getParent();
-
-                if (MI != UseMI) {
-                  // The phi node has a user that is not MI, bail...
-                  return false;
-                }
-              }
-            }
-          }
+bool PPCCTRLoops::convertToCTRLoop(Loop *L) {
+  bool MadeChange = false;
 
-          DeadPhis.push_back(OnePhi);
-        } else {
-          // This def has a non-debug use. Don't delete the instruction!
-          return false;
-        }
-      }
-    }
+  Triple TT = Triple(L->getHeader()->getParent()->getParent()->
+                     getTargetTriple());
+  if (!TT.isArch32Bit() && !TT.isArch64Bit())
+    return MadeChange; // Unknown arch. type.
+
+  // Process nested loops first.
+  for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I) {
+    MadeChange |= convertToCTRLoop(*I);
   }
 
-  // If there are no defs with uses, the instruction is dead.
-  return true;
-}
+  // If a nested loop has been converted, then we can't convert this loop.
+  if (MadeChange)
+    return MadeChange;
+
+#ifndef NDEBUG
+  // Stop trying after reaching the limit (if any).
+  int Limit = CTRLoopLimit;
+  if (Limit >= 0) {
+    if (Counter >= CTRLoopLimit)
+      return false;
+    Counter++;
+  }
+#endif
+
+  // We don't want to spill/restore the counter register, and so we don't
+  // want to use the counter register if the loop contains calls.
+  for (Loop::block_iterator I = L->block_begin(), IE = L->block_end();
+       I != IE; ++I)
+    if (mightUseCTR(TT, *I))
+      return MadeChange;
+
+  SmallVector<BasicBlock*, 4> ExitingBlocks;
+  L->getExitingBlocks(ExitingBlocks);
+
+  BasicBlock *CountedExitBlock = 0;
+  const SCEV *ExitCount = 0;
+  BranchInst *CountedExitBranch = 0;
+  for (SmallVectorImpl<BasicBlock *>::iterator I = ExitingBlocks.begin(),
+       IE = ExitingBlocks.end(); I != IE; ++I) {
+    const SCEV *EC = SE->getExitCount(L, *I);
+    DEBUG(dbgs() << "Exit Count for " << *L << " from block " <<
+                    (*I)->getName() << ": " << *EC << "\n");
+    if (isa<SCEVCouldNotCompute>(EC))
+      continue;
+    if (const SCEVConstant *ConstEC = dyn_cast<SCEVConstant>(EC)) {
+      if (ConstEC->getValue()->isZero())
+        continue;
+    } else if (!SE->isLoopInvariant(EC, L))
+      continue;
+
+    if (SE->getTypeSizeInBits(EC->getType()) > (TT.isArch64Bit() ? 64 : 32))
+      continue;
+
+    // We now have a loop-invariant count of loop iterations (which is not the
+    // constant zero) for which we know that this loop will not exit via this
+    // exisiting block.
+
+    // We need to make sure that this block will run on every loop iteration.
+    // For this to be true, we must dominate all blocks with backedges. Such
+    // blocks are in-loop predecessors to the header block.
+    bool NotAlways = false;
+    for (pred_iterator PI = pred_begin(L->getHeader()),
+         PIE = pred_end(L->getHeader()); PI != PIE; ++PI) {
+      if (!L->contains(*PI))
+        continue;
 
-void PPCCTRLoops::removeIfDead(MachineInstr *MI) {
-  // This procedure was essentially copied from DeadMachineInstructionElim
+      if (!DT->dominates(*I, *PI)) {
+        NotAlways = true;
+        break;
+      }
+    }
 
-  SmallVector<MachineInstr *, 1> DeadPhis;
-  if (isDead(MI, DeadPhis)) {
-    DEBUG(dbgs() << "CTR looping will remove: " << *MI);
+    if (NotAlways)
+      continue;
 
-    // It is possible that some DBG_VALUE instructions refer to this
-    // instruction.  Examine each def operand for such references;
-    // if found, mark the DBG_VALUE as undef (but don't delete it).
-    for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
-      const MachineOperand &MO = MI->getOperand(i);
-      if (!MO.isReg() || !MO.isDef())
+    // Make sure this blocks ends with a conditional branch.
+    Instruction *TI = (*I)->getTerminator();
+    if (!TI)
+      continue;
+
+    if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
+      if (!BI->isConditional())
         continue;
-      unsigned Reg = MO.getReg();
-      MachineRegisterInfo::use_iterator nextI;
-      for (MachineRegisterInfo::use_iterator I = MRI->use_begin(Reg),
-           E = MRI->use_end(); I!=E; I=nextI) {
-        nextI = llvm::next(I);  // I is invalidated by the setReg
-        MachineOperand& Use = I.getOperand();
-        MachineInstr *UseMI = Use.getParent();
-        if (UseMI==MI)
-          continue;
-        if (Use.isDebug()) // this might also be a instr -> phi -> instr case
-                           // which can also be removed.
-          UseMI->getOperand(0).setReg(0U);
-      }
-    }
 
-    MI->eraseFromParent();
-    for (unsigned i = 0; i < DeadPhis.size(); ++i) {
-      DeadPhis[i]->eraseFromParent();
-    }
+      CountedExitBranch = BI;
+    } else
+      continue;
+
+    // Note that this block may not be the loop latch block, even if the loop
+    // has a latch block.
+    CountedExitBlock = *I;
+    ExitCount = EC;
+    break;
   }
+
+  if (!CountedExitBlock)
+    return MadeChange;
+
+  BasicBlock *Preheader = L->getLoopPreheader();
+
+  // If we don't have a preheader, then insert one. If we already have a
+  // preheader, then we can use it (except if the preheader contains a use of
+  // the CTR register because some such uses might be reordered by the
+  // selection DAG after the mtctr instruction).
+  if (!Preheader || mightUseCTR(TT, Preheader))
+    Preheader = InsertPreheaderForLoop(L, this);
+  if (!Preheader)
+    return MadeChange;
+
+  DEBUG(dbgs() << "Preheader for exit count: " << Preheader->getName() << "\n");
+
+  // Insert the count into the preheader and replace the condition used by the
+  // selected branch.
+  MadeChange = true;
+
+  SCEVExpander SCEVE(*SE, "loopcnt");
+  LLVMContext &C = SE->getContext();
+  Type *CountType = TT.isArch64Bit() ? Type::getInt64Ty(C) :
+                                       Type::getInt32Ty(C);
+  if (!ExitCount->getType()->isPointerTy() &&
+      ExitCount->getType() != CountType)
+    ExitCount = SE->getZeroExtendExpr(ExitCount, CountType);
+  ExitCount = SE->getAddExpr(ExitCount,
+                             SE->getConstant(CountType, 1)); 
+  Value *ECValue = SCEVE.expandCodeFor(ExitCount, CountType,
+                                       Preheader->getTerminator());
+
+  IRBuilder<> CountBuilder(Preheader->getTerminator());
+  Module *M = Preheader->getParent()->getParent();
+  Value *MTCTRFunc = Intrinsic::getDeclaration(M, Intrinsic::ppc_mtctr,
+                                               CountType);
+  CountBuilder.CreateCall(MTCTRFunc, ECValue);
+
+  IRBuilder<> CondBuilder(CountedExitBranch);
+  Value *DecFunc =
+    Intrinsic::getDeclaration(M, Intrinsic::ppc_is_decremented_ctr_nonzero);
+  Value *NewCond = CondBuilder.CreateCall(DecFunc);
+  Value *OldCond = CountedExitBranch->getCondition();
+  CountedExitBranch->setCondition(NewCond);
+
+  // The false branch must exit the loop.
+  if (!L->contains(CountedExitBranch->getSuccessor(0)))
+    CountedExitBranch->swapSuccessors();
+
+  // The old condition may be dead now, and may have even created a dead PHI
+  // (the original induction variable).
+  RecursivelyDeleteTriviallyDeadInstructions(OldCond);
+  DeleteDeadPHIs(CountedExitBlock);
+
+  ++NumCTRLoops;
+  return MadeChange;
 }
 
-/// converToCTRLoop - check if the loop is a candidate for
-/// converting to a CTR loop.  If so, then perform the
-/// transformation.
-///
-/// This function works on innermost loops first.  A loop can
-/// be converted if it is a counting loop; either a register
-/// value or an immediate.
-///
-/// The code makes several assumptions about the representation
-/// of the loop in llvm.
-bool PPCCTRLoops::convertToCTRLoop(MachineLoop *L) {
-  bool Changed = false;
-  // Process nested loops first.
-  for (MachineLoop::iterator I = L->begin(), E = L->end(); I != E; ++I) {
-    Changed |= convertToCTRLoop(*I);
-  }
-  // If a nested loop has been converted, then we can't convert this loop.
-  if (Changed) {
-    return Changed;
+#ifndef NDEBUG
+static bool clobbersCTR(const MachineInstr *MI) {
+  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+    const MachineOperand &MO = MI->getOperand(i);
+    if (MO.isReg()) {
+      if (MO.isDef() && (MO.getReg() == PPC::CTR || MO.getReg() == PPC::CTR8))
+        return true;
+    } else if (MO.isRegMask()) {
+      if (MO.clobbersPhysReg(PPC::CTR) || MO.clobbersPhysReg(PPC::CTR8))
+        return true;
+    }
   }
 
-  SmallVector<MachineInstr *, 2> OldInsts;
-  // Are we able to determine the trip count for the loop?
-  CountValue *TripCount = getTripCount(L, OldInsts);
-  if (TripCount == 0) {
-    DEBUG(dbgs() << "failed to get trip count!\n");
-    return false;
-  }
+  return false;
+}
 
-  if (TripCount->isImm()) {
-    DEBUG(dbgs() << "constant trip count: " << TripCount->getImm() << "\n");
+static bool verifyCTRBranch(MachineBasicBlock *MBB,
+                            MachineBasicBlock::iterator I) {
+  MachineBasicBlock::iterator BI = I;
+  SmallSet<MachineBasicBlock *, 16>   Visited;
+  SmallVector<MachineBasicBlock *, 8> Preds;
+  bool CheckPreds;
+
+  if (I == MBB->begin()) {
+    Visited.insert(MBB);
+    goto queue_preds;
+  } else
+    --I;
+
+check_block:
+  Visited.insert(MBB);
+  if (I == MBB->end())
+    goto queue_preds;
+
+  CheckPreds = true;
+  for (MachineBasicBlock::iterator IE = MBB->begin();; --I) {
+    unsigned Opc = I->getOpcode();
+    if (Opc == PPC::MTCTRloop || Opc == PPC::MTCTR8loop) {
+      CheckPreds = false;
+      break;
+    }
 
-    // FIXME: We currently can't form 64-bit constants
-    // (including 32-bit unsigned constants)
-    if (!isInt<32>(TripCount->getImm()))
+    if (I != BI && clobbersCTR(I)) {
+      DEBUG(dbgs() << "BB#" << MBB->getNumber() << " (" <<
+                      MBB->getFullName() << ") instruction " << *I <<
+                      " clobbers CTR, invalidating " << "BB#" <<
+                      BI->getParent()->getNumber() << " (" <<
+                      BI->getParent()->getFullName() << ") instruction " <<
+                      *BI << "\n");
       return false;
-  }
+    }
 
-  // Does the loop contain any invalid instructions?
-  if (containsInvalidInstruction(L)) {
-    return false;
+    if (I == IE)
+      break;
   }
-  MachineBasicBlock *Preheader = L->getLoopPreheader();
-  // No preheader means there's not place for the loop instr.
-  if (Preheader == 0) {
-    return false;
-  }
-  MachineBasicBlock::iterator InsertPos = Preheader->getFirstTerminator();
 
-  DebugLoc dl;
-  if (InsertPos != Preheader->end())
-    dl = InsertPos->getDebugLoc();
+  if (!CheckPreds && Preds.empty())
+    return true;
 
-  MachineBasicBlock *LastMBB = L->getExitingBlock();
-  // Don't generate CTR loop if the loop has more than one exit.
-  if (LastMBB == 0) {
-    return false;
-  }
-  MachineBasicBlock::iterator LastI = LastMBB->getFirstTerminator();
-
-  // Determine the loop start.
-  MachineBasicBlock *LoopStart = L->getTopBlock();
-  if (L->getLoopLatch() != LastMBB) {
-    // When the exit and latch are not the same, use the latch block as the
-    // start.
-    // The loop start address is used only after the 1st iteration, and the loop
-    // latch may contains instrs. that need to be executed after the 1st iter.
-    LoopStart = L->getLoopLatch();
-    // Make sure the latch is a successor of the exit, otherwise it won't work.
-    if (!LastMBB->isSuccessor(LoopStart)) {
+  if (CheckPreds) {
+queue_preds:
+    if (MachineFunction::iterator(MBB) == MBB->getParent()->begin()) {
+      DEBUG(dbgs() << "Unable to find a MTCTR instruction for BB#" <<
+                      BI->getParent()->getNumber() << " (" <<
+                      BI->getParent()->getFullName() << ") instruction " <<
+                      *BI << "\n");
       return false;
     }
+
+    for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
+         PIE = MBB->pred_end(); PI != PIE; ++PI)
+      Preds.push_back(*PI);
   }
 
-  // Convert the loop to a CTR loop
-  DEBUG(dbgs() << "Change to CTR loop at "; L->dump());
-
-  MachineFunction *MF = LastMBB->getParent();
-  const PPCSubtarget &Subtarget = MF->getTarget().getSubtarget<PPCSubtarget>();
-  bool isPPC64 = Subtarget.isPPC64();
-
-  const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
-  const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
-  const TargetRegisterClass *RC = isPPC64 ? G8RC : GPRC;
-
-  unsigned CountReg;
-  if (TripCount->isReg()) {
-    // Create a copy of the loop count register.
-    const TargetRegisterClass *SrcRC =
-      MF->getRegInfo().getRegClass(TripCount->getReg());
-    CountReg = MF->getRegInfo().createVirtualRegister(RC);
-    unsigned CopyOp = (isPPC64 && GPRC->hasSubClassEq(SrcRC)) ?
-                        (unsigned) PPC::EXTSW_32_64 :
-                        (unsigned) TargetOpcode::COPY;
-    BuildMI(*Preheader, InsertPos, dl,
-            TII->get(CopyOp), CountReg).addReg(TripCount->getReg());
-    if (TripCount->isNeg()) {
-      unsigned CountReg1 = CountReg;
-      CountReg = MF->getRegInfo().createVirtualRegister(RC);
-      BuildMI(*Preheader, InsertPos, dl,
-              TII->get(isPPC64 ? PPC::NEG8 : PPC::NEG),
-                       CountReg).addReg(CountReg1);
+  do {
+    MBB = Preds.pop_back_val();
+    if (!Visited.count(MBB)) {
+      I = MBB->getLastNonDebugInstr();
+      goto check_block;
     }
-  } else {
-    assert(TripCount->isImm() && "Expecting immedate vaule for trip count");
-    // Put the trip count in a register for transfer into the count register.
-
-    int64_t CountImm = TripCount->getImm();
-    if (TripCount->isNeg())
-      CountImm = -CountImm;
-
-    CountReg = MF->getRegInfo().createVirtualRegister(RC);
-    if (abs64(CountImm) > 0x7FFF) {
-      BuildMI(*Preheader, InsertPos, dl,
-              TII->get(isPPC64 ? PPC::LIS8 : PPC::LIS),
-              CountReg).addImm((CountImm >> 16) & 0xFFFF);
-      unsigned CountReg1 = CountReg;
-      CountReg = MF->getRegInfo().createVirtualRegister(RC);
-      BuildMI(*Preheader, InsertPos, dl,
-              TII->get(isPPC64 ? PPC::ORI8 : PPC::ORI),
-              CountReg).addReg(CountReg1).addImm(CountImm & 0xFFFF);
-    } else {
-      BuildMI(*Preheader, InsertPos, dl,
-              TII->get(isPPC64 ? PPC::LI8 : PPC::LI),
-              CountReg).addImm(CountImm);
-    }
-  }
+  } while (!Preds.empty());
 
-  // Add the mtctr instruction to the beginning of the loop.
-  BuildMI(*Preheader, InsertPos, dl,
-          TII->get(isPPC64 ? PPC::MTCTR8 : PPC::MTCTR)).addReg(CountReg,
-            TripCount->isImm() ? RegState::Kill : 0);
-
-  // Make sure the loop start always has a reference in the CFG.  We need to
-  // create a BlockAddress operand to get this mechanism to work both the
-  // MachineBasicBlock and BasicBlock objects need the flag set.
-  LoopStart->setHasAddressTaken();
-  // This line is needed to set the hasAddressTaken flag on the BasicBlock
-  // object
-  BlockAddress::get(const_cast<BasicBlock *>(LoopStart->getBasicBlock()));
-
-  // Replace the loop branch with a bdnz instruction.
-  dl = LastI->getDebugLoc();
-  const std::vector<MachineBasicBlock*> Blocks = L->getBlocks();
-  for (unsigned i = 0, e = Blocks.size(); i != e; ++i) {
-    MachineBasicBlock *MBB = Blocks[i];
-    if (MBB != Preheader)
-      MBB->addLiveIn(isPPC64 ? PPC::CTR8 : PPC::CTR);
-  }
+  return true;
+}
 
-  // The loop ends with either:
-  //  - a conditional branch followed by an unconditional branch, or
-  //  - a conditional branch to the loop start.
-  assert(LastI->getOpcode() == PPC::BCC &&
-         "loop end must start with a BCC instruction");
-  // Either the BCC branches to the beginning of the loop, or it
-  // branches out of the loop and there is an unconditional branch
-  // to the start of the loop.
-  MachineBasicBlock *BranchTarget = LastI->getOperand(2).getMBB();
-  BuildMI(*LastMBB, LastI, dl,
-        TII->get((BranchTarget == LoopStart) ?
-                 (isPPC64 ? PPC::BDNZ8 : PPC::BDNZ) :
-                 (isPPC64 ? PPC::BDZ8 : PPC::BDZ))).addMBB(BranchTarget);
-
-  // Conditional branch; just delete it.
-  DEBUG(dbgs() << "Removing old branch: " << *LastI);
-  LastMBB->erase(LastI);
-
-  delete TripCount;
-
-  // The induction operation (add) and the comparison (cmpwi) may now be
-  // unneeded. If these are unneeded, then remove them.
-  for (unsigned i = 0; i < OldInsts.size(); ++i)
-    removeIfDead(OldInsts[i]);
+bool PPCCTRLoopsVerify::runOnMachineFunction(MachineFunction &MF) {
+  MDT = &getAnalysis<MachineDominatorTree>();
+
+  // Verify that all bdnz/bdz instructions are dominated by a loop mtctr before
+  // any other instructions that might clobber the ctr register.
+  for (MachineFunction::iterator I = MF.begin(), IE = MF.end();
+       I != IE; ++I) {
+    MachineBasicBlock *MBB = I;
+    if (!MDT->isReachableFromEntry(MBB))
+      continue;
+
+    for (MachineBasicBlock::iterator MII = MBB->getFirstTerminator(),
+      MIIE = MBB->end(); MII != MIIE; ++MII) {
+      unsigned Opc = MII->getOpcode();
+      if (Opc == PPC::BDNZ8 || Opc == PPC::BDNZ ||
+          Opc == PPC::BDZ8  || Opc == PPC::BDZ)
+        if (!verifyCTRBranch(MBB, MII))
+          llvm_unreachable("Invalid PPC CTR loop!");
+    }
+  }
 
-  ++NumCTRLoops;
-  return true;
+  return false;
 }
+#endif // NDEBUG