X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FIfConversion.cpp;h=9dbd6d1241caabd354e4b2fb2c571bc43946ba86;hb=9390cd0e86cb3b79f6836acab2a27b275e5bde9e;hp=fb53377b98ba0959468d0a9fca07bb1f77f003c0;hpb=303595942502f17c087fa28874c2b89117148c45;p=oota-llvm.git

diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index fb53377b98b..9dbd6d1241c 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -21,6 +21,8 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/STLExtras.h"
@@ -56,7 +58,7 @@ STATISTIC(NumIfConvBBs,    "Number of if-converted blocks");
 STATISTIC(NumDupBBs,       "Number of duplicated blocks");
 
 namespace {
-  class IfConverter : public MachineFunctionPass {
+  class VISIBILITY_HIDDEN IfConverter : public MachineFunctionPass {
     enum IfcvtKind {
       ICNotClassfied,  // BB data valid, but not classified.
       ICSimpleFalse,   // Same as ICSimple, but on the false path.
@@ -103,8 +105,8 @@ namespace {
       MachineBasicBlock *BB;
       MachineBasicBlock *TrueBB;
       MachineBasicBlock *FalseBB;
-      std::vector<MachineOperand> BrCond;
-      std::vector<MachineOperand> Predicate;
+      SmallVector<MachineOperand, 4> BrCond;
+      SmallVector<MachineOperand, 4> Predicate;
       BBInfo() : IsDone(false), IsBeingAnalyzed(false),
                  IsAnalyzed(false), IsEnqueued(false), IsBrAnalyzable(false),
                  HasFallThrough(false), IsUnpredicable(false),
@@ -115,7 +117,7 @@ namespace {
     /// IfcvtToken - Record information about pending if-conversions to attemp:
     /// BBI             - Corresponding BBInfo.
     /// Kind            - Type of block. See IfcvtKind.
-    /// NeedSubsumsion  - True if the to be predicated BB has already been
+    /// NeedSubsumption - True if the to-be-predicated BB has already been
     ///                   predicated.
     /// NumDups      - Number of instructions that would be duplicated due
     ///                   to this if-conversion. (For diamonds, the number of
@@ -126,11 +128,11 @@ namespace {
     struct IfcvtToken {
       BBInfo &BBI;
       IfcvtKind Kind;
-      bool NeedSubsumsion;
+      bool NeedSubsumption;
       unsigned NumDups;
       unsigned NumDups2;
       IfcvtToken(BBInfo &b, IfcvtKind k, bool s, unsigned d, unsigned d2 = 0)
-        : BBI(b), Kind(k), NeedSubsumsion(s), NumDups(d), NumDups2(d2) {}
+        : BBI(b), Kind(k), NeedSubsumption(s), NumDups(d), NumDups2(d2) {}
     };
 
     /// Roots - Basic blocks that do not have successors. These are the starting
@@ -144,12 +146,13 @@ namespace {
     const TargetLowering *TLI;
     const TargetInstrInfo *TII;
     bool MadeChange;
+    int FnNum;
   public:
     static char ID;
-    IfConverter() : MachineFunctionPass((intptr_t)&ID) {}
+    IfConverter() : MachineFunctionPass(&ID), FnNum(-1) {}
 
     virtual bool runOnMachineFunction(MachineFunction &MF);
-    virtual const char *getPassName() const { return "If converter"; }
+    virtual const char *getPassName() const { return "If Converter"; }
 
   private:
     bool ReverseBranchCondition(BBInfo &BBI);
@@ -161,7 +164,7 @@ namespace {
     void ScanInstructions(BBInfo &BBI);
     BBInfo &AnalyzeBlock(MachineBasicBlock *BB,
                          std::vector<IfcvtToken*> &Tokens);
-    bool FeasibilityAnalysis(BBInfo &BBI, std::vector<MachineOperand> &Cond,
+    bool FeasibilityAnalysis(BBInfo &BBI, SmallVectorImpl<MachineOperand> &Cond,
                              bool isTriangle = false, bool RevBranch = false);
     bool AnalyzeBlocks(MachineFunction &MF,
                        std::vector<IfcvtToken*> &Tokens);
@@ -173,9 +176,9 @@ namespace {
                           unsigned NumDups1, unsigned NumDups2);
     void PredicateBlock(BBInfo &BBI,
                         MachineBasicBlock::iterator E,
-                        std::vector<MachineOperand> &Cond);
+                        SmallVectorImpl<MachineOperand> &Cond);
     void CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI,
-                               std::vector<MachineOperand> &Cond,
+                               SmallVectorImpl<MachineOperand> &Cond,
                                bool IgnoreBr = false);
     void MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI);
 
@@ -197,10 +200,10 @@ namespace {
       if (Incr1 > Incr2)
         return true;
       else if (Incr1 == Incr2) {
-        // Favors subsumsion.
-        if (C1->NeedSubsumsion == false && C2->NeedSubsumsion == true)
+        // Favors subsumption.
+        if (C1->NeedSubsumption == false && C2->NeedSubsumption == true)
           return true;
-        else if (C1->NeedSubsumsion == C2->NeedSubsumsion) {
+        else if (C1->NeedSubsumption == C2->NeedSubsumption) {
           // Favors diamond over triangle, etc.
           if ((unsigned)C1->Kind < (unsigned)C2->Kind)
             return true;
@@ -215,6 +218,9 @@ namespace {
   char IfConverter::ID = 0;
 }
 
+static RegisterPass<IfConverter>
+X("if-converter", "If Converter");
+
 FunctionPass *llvm::createIfConverterPass() { return new IfConverter(); }
 
 bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
@@ -222,9 +228,8 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
   TII = MF.getTarget().getInstrInfo();
   if (!TII) return false;
 
-  static int FnNum = -1;
-  DOUT << "\nIfcvt: function (" << ++FnNum <<  ") \'"
-       << MF.getFunction()->getName() << "\'";
+  DEBUG(errs() << "\nIfcvt: function (" << ++FnNum <<  ") \'"
+        << MF.getFunction()->getName() << "\'");
 
   if (FnNum < IfCvtFnStart || (IfCvtFnStop != -1 && FnNum > IfCvtFnStop)) {
     DOUT << " skipped\n";
@@ -245,14 +250,18 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
   unsigned NumIfCvts = NumSimple + NumSimpleFalse + NumTriangle +
     NumTriangleRev + NumTriangleFalse + NumTriangleFRev + NumDiamonds;
   while (IfCvtLimit == -1 || (int)NumIfCvts < IfCvtLimit) {
-    // Do an intial analysis for each basic block and finding all the potential
-    // candidates to perform if-convesion.
+    // Do an initial analysis for each basic block and find all the potential
+    // candidates to perform if-conversion.
     bool Change = AnalyzeBlocks(MF, Tokens);
     while (!Tokens.empty()) {
       IfcvtToken *Token = Tokens.back();
       Tokens.pop_back();
       BBInfo &BBI = Token->BBI;
       IfcvtKind Kind = Token->Kind;
+      unsigned NumDups = Token->NumDups;
+      unsigned NumDups2 = Token->NumDups2;
+
+      delete Token;
 
       // If the block has been evicted out of the queue or it has already been
       // marked dead (due to it being predicated), then skip it.
@@ -278,9 +287,10 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
                  : BBI.TrueBB->getNumber()) << ") ";
         RetVal = IfConvertSimple(BBI, Kind);
         DOUT << (RetVal ? "succeeded!" : "failed!") << "\n";
-        if (RetVal)
+        if (RetVal) {
           if (isFalse) NumSimpleFalse++;
           else         NumSimple++;
+        }
        break;
       }
       case ICTriangle:
@@ -319,7 +329,7 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
         DOUT << "Ifcvt (Diamond): BB#" << BBI.BB->getNumber() << " (T:"
              << BBI.TrueBB->getNumber() << ",F:"
              << BBI.FalseBB->getNumber() << ") ";
-        RetVal = IfConvertDiamond(BBI, Kind, Token->NumDups, Token->NumDups2);
+        RetVal = IfConvertDiamond(BBI, Kind, NumDups, NumDups2);
         DOUT << (RetVal ? "succeeded!" : "failed!") << "\n";
         if (RetVal) NumDiamonds++;
         break;
@@ -367,7 +377,7 @@ static MachineBasicBlock *findFalseBlock(MachineBasicBlock *BB,
 }
 
 /// ReverseBranchCondition - Reverse the condition of the end of the block
-/// branchs. Swap block's 'true' and 'false' successors.
+/// branch. Swap block's 'true' and 'false' successors.
 bool IfConverter::ReverseBranchCondition(BBInfo &BBI) {
   if (!TII->ReverseBranchCondition(BBI.BrCond)) {
     TII->RemoveBranch(*BBI.BB);
@@ -429,7 +439,7 @@ bool IfConverter::ValidTriangle(BBInfo &TrueBBI, BBInfo &FalseBBI,
     unsigned Size = TrueBBI.NonPredSize;
     if (TrueBBI.IsBrAnalyzable) {
       if (TrueBBI.TrueBB && TrueBBI.BrCond.empty())
-        // End with an unconditional branch. It will be removed.
+        // Ends with an unconditional branch. It will be removed.
         --Size;
       else {
         MachineBasicBlock *FExit = FalseBranch
@@ -539,13 +549,16 @@ void IfConverter::ScanInstructions(BBInfo &BBI) {
     // fallthrough.
     if (!BBI.FalseBB)
       BBI.FalseBB = findFalseBlock(BBI.BB, BBI.TrueBB);  
-    assert(BBI.FalseBB && "Expected to find the fallthrough block!");
+    if (!BBI.FalseBB) {
+      // Malformed bcc? True and false blocks are the same?
+      BBI.IsUnpredicable = true;
+      return;
+    }
   }
 
   // Then scan all the instructions.
   BBI.NonPredSize = 0;
   BBI.ClobbersPred = false;
-  bool SeenCondBr = false;
   for (MachineBasicBlock::iterator I = BBI.BB->begin(), E = BBI.BB->end();
        I != E; ++I) {
     const TargetInstrDesc &TID = I->getDesc();
@@ -565,16 +578,13 @@ void IfConverter::ScanInstructions(BBInfo &BBI) {
         BBI.IsUnpredicable = true;
         return;
       }
-        
     }
 
     if (BBI.ClobbersPred && !isPredicated) {
       // Predicate modification instruction should end the block (except for
       // already predicated instructions and end of block branches).
       if (isCondBr) {
-        SeenCondBr = true;
-
-        // Conditional branches is not predicable. But it may be eliminated.
+        // A conditional branch is not predicable, but it may be eliminated.
         continue;
       }
 
@@ -600,7 +610,7 @@ void IfConverter::ScanInstructions(BBInfo &BBI) {
 /// FeasibilityAnalysis - Determine if the block is a suitable candidate to be
 /// predicated by the specified predicate.
 bool IfConverter::FeasibilityAnalysis(BBInfo &BBI,
-                                      std::vector<MachineOperand> &Pred,
+                                      SmallVectorImpl<MachineOperand> &Pred,
                                       bool isTriangle, bool RevBranch) {
   // If the block is dead or unpredicable, then it cannot be predicated.
   if (BBI.IsDone || BBI.IsUnpredicable)
@@ -615,9 +625,9 @@ bool IfConverter::FeasibilityAnalysis(BBInfo &BBI,
     if (!isTriangle)
       return false;
 
-    // Test predicate subsumsion.
-    std::vector<MachineOperand> RevPred(Pred);
-    std::vector<MachineOperand> Cond(BBI.BrCond);
+    // Test predicate subsumption.
+    SmallVector<MachineOperand, 4> RevPred(Pred.begin(), Pred.end());
+    SmallVector<MachineOperand, 4> Cond(BBI.BrCond.begin(), BBI.BrCond.end());
     if (RevBranch) {
       if (TII->ReverseBranchCondition(Cond))
         return false;
@@ -645,7 +655,7 @@ IfConverter::BBInfo &IfConverter::AnalyzeBlock(MachineBasicBlock *BB,
 
   ScanInstructions(BBI);
 
-  // Unanalyable or ends with fallthrough or unconditional branch.
+  // Unanalyzable or ends with fallthrough or unconditional branch.
   if (!BBI.IsBrAnalyzable || BBI.BrCond.empty()) {
     BBI.IsBeingAnalyzed = false;
     BBI.IsAnalyzed = true;
@@ -659,6 +669,13 @@ IfConverter::BBInfo &IfConverter::AnalyzeBlock(MachineBasicBlock *BB,
     return BBI;
   }
 
+  // Do not ifcvt if true and false fallthrough blocks are the same.
+  if (!BBI.FalseBB) {
+    BBI.IsBeingAnalyzed = false;
+    BBI.IsAnalyzed = true;
+    return BBI;
+  }
+
   BBInfo &TrueBBI  = AnalyzeBlock(BBI.TrueBB, Tokens);
   BBInfo &FalseBBI = AnalyzeBlock(BBI.FalseBB, Tokens);
 
@@ -668,7 +685,7 @@ IfConverter::BBInfo &IfConverter::AnalyzeBlock(MachineBasicBlock *BB,
     return BBI;
   }
 
-  std::vector<MachineOperand> RevCond(BBI.BrCond);
+  SmallVector<MachineOperand, 4> RevCond(BBI.BrCond.begin(), BBI.BrCond.end());
   bool CanRevCond = !TII->ReverseBranchCondition(RevCond);
 
   unsigned Dups = 0;
@@ -811,7 +828,7 @@ void IfConverter::InvalidatePreds(MachineBasicBlock *BB) {
 ///
 static void InsertUncondBranch(MachineBasicBlock *BB, MachineBasicBlock *ToBB,
                                const TargetInstrInfo *TII) {
-  std::vector<MachineOperand> NoCond;
+  SmallVector<MachineOperand, 0> NoCond;
   TII->InsertBranch(*BB, ToBB, NULL, NoCond);
 }
 
@@ -819,7 +836,7 @@ static void InsertUncondBranch(MachineBasicBlock *BB, MachineBasicBlock *ToBB,
 /// successors.
 void IfConverter::RemoveExtraEdges(BBInfo &BBI) {
   MachineBasicBlock *TBB = NULL, *FBB = NULL;
-  std::vector<MachineOperand> Cond;
+  SmallVector<MachineOperand, 4> Cond;
   if (!TII->AnalyzeBranch(*BBI.BB, TBB, FBB, Cond))
     BBI.BB->CorrectExtraCFGEdges(TBB, FBB, !Cond.empty());
 }
@@ -832,7 +849,7 @@ bool IfConverter::IfConvertSimple(BBInfo &BBI, IfcvtKind Kind) {
   BBInfo *CvtBBI = &TrueBBI;
   BBInfo *NextBBI = &FalseBBI;
 
-  std::vector<MachineOperand> Cond(BBI.BrCond);
+  SmallVector<MachineOperand, 4> Cond(BBI.BrCond.begin(), BBI.BrCond.end());
   if (Kind == ICSimpleFalse)
     std::swap(CvtBBI, NextBBI);
 
@@ -845,11 +862,12 @@ bool IfConverter::IfConvertSimple(BBInfo &BBI, IfcvtKind Kind) {
   }
 
   if (Kind == ICSimpleFalse)
-    TII->ReverseBranchCondition(Cond);
+    if (TII->ReverseBranchCondition(Cond))
+      assert(false && "Unable to reverse branch condition!");
 
   if (CvtBBI->BB->pred_size() > 1) {
     BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB);
-    // Copy instructions in the true block, predicate them add them to
+    // Copy instructions in the true block, predicate them, and add them to
     // the entry block.
     CopyAndPredicateBlock(BBI, *CvtBBI, Cond);
   } else {
@@ -897,7 +915,7 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) {
   BBInfo *CvtBBI = &TrueBBI;
   BBInfo *NextBBI = &FalseBBI;
 
-  std::vector<MachineOperand> Cond(BBI.BrCond);
+  SmallVector<MachineOperand, 4> Cond(BBI.BrCond.begin(), BBI.BrCond.end());
   if (Kind == ICTriangleFalse || Kind == ICTriangleFRev)
     std::swap(CvtBBI, NextBBI);
 
@@ -910,21 +928,23 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) {
   }
 
   if (Kind == ICTriangleFalse || Kind == ICTriangleFRev)
-    TII->ReverseBranchCondition(Cond);
+    if (TII->ReverseBranchCondition(Cond))
+      assert(false && "Unable to reverse branch condition!");
 
   if (Kind == ICTriangleRev || Kind == ICTriangleFRev) {
-    ReverseBranchCondition(*CvtBBI);
-    // BB has been changed, modify its predecessors (except for this
-    // one) so they don't get ifcvt'ed based on bad intel.
-    for (MachineBasicBlock::pred_iterator PI = CvtBBI->BB->pred_begin(),
-           E = CvtBBI->BB->pred_end(); PI != E; ++PI) {
-      MachineBasicBlock *PBB = *PI;
-      if (PBB == BBI.BB)
-        continue;
-      BBInfo &PBBI = BBAnalysis[PBB->getNumber()];
-      if (PBBI.IsEnqueued) {
-        PBBI.IsAnalyzed = false;
-        PBBI.IsEnqueued = false;
+    if (ReverseBranchCondition(*CvtBBI)) {
+      // BB has been changed, modify its predecessors (except for this
+      // one) so they don't get ifcvt'ed based on bad intel.
+      for (MachineBasicBlock::pred_iterator PI = CvtBBI->BB->pred_begin(),
+             E = CvtBBI->BB->pred_end(); PI != E; ++PI) {
+        MachineBasicBlock *PBB = *PI;
+        if (PBB == BBI.BB)
+          continue;
+        BBInfo &PBBI = BBAnalysis[PBB->getNumber()];
+        if (PBBI.IsEnqueued) {
+          PBBI.IsAnalyzed = false;
+          PBBI.IsEnqueued = false;
+        }
       }
     }
   }
@@ -933,16 +953,14 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) {
   bool DupBB = CvtBBI->BB->pred_size() > 1;
   if (DupBB) {
     BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB);
-    // Copy instructions in the true block, predicate them add them to
+    // Copy instructions in the true block, predicate them, and add them to
     // the entry block.
     CopyAndPredicateBlock(BBI, *CvtBBI, Cond, true);
   } else {
     // Predicate the 'true' block after removing its branch.
     CvtBBI->NonPredSize -= TII->RemoveBranch(*CvtBBI->BB);
     PredicateBlock(*CvtBBI, CvtBBI->BB->end(), Cond);
-  }
 
-  if (!DupBB) {
     // Now merge the entry of the triangle with the true block.
     BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB);
     MergeBlocks(BBI, *CvtBBI);
@@ -950,7 +968,8 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) {
 
   // If 'true' block has a 'false' successor, add an exit branch to it.
   if (HasEarlyExit) {
-    std::vector<MachineOperand> RevCond(CvtBBI->BrCond);
+    SmallVector<MachineOperand, 4> RevCond(CvtBBI->BrCond.begin(),
+                                           CvtBBI->BrCond.end());
     if (TII->ReverseBranchCondition(RevCond))
       assert(false && "Unable to reverse branch condition!");
     TII->InsertBranch(*BBI.BB, CvtBBI->FalseBB, NULL, RevCond);
@@ -958,7 +977,7 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) {
   }
 
   // Merge in the 'false' block if the 'false' block has no other
-  // predecessors. Otherwise, add a unconditional branch from to 'false'.
+  // predecessors. Otherwise, add an unconditional branch to 'false'.
   bool FalseBBDead = false;
   bool IterIfcvt = true;
   bool isFallThrough = canFallThroughTo(BBI.BB, NextBBI->BB);
@@ -1000,7 +1019,7 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind,
   BBInfo &TrueBBI  = BBAnalysis[BBI.TrueBB->getNumber()];
   BBInfo &FalseBBI = BBAnalysis[BBI.FalseBB->getNumber()];
   MachineBasicBlock *TailBB = TrueBBI.TrueBB;
-  // True block must fall through or ended with unanalyzable terminator.
+  // True block must fall through or end with an unanalyzable terminator.
   if (!TailBB) {
     if (blockAlwaysFallThrough(TrueBBI))
       TailBB = FalseBBI.TrueBB;
@@ -1022,10 +1041,11 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind,
   // block would clobber the predicate, in that case, do the opposite.
   BBInfo *BBI1 = &TrueBBI;
   BBInfo *BBI2 = &FalseBBI;
-  std::vector<MachineOperand> RevCond(BBI.BrCond);
-  TII->ReverseBranchCondition(RevCond);
-  std::vector<MachineOperand> *Cond1 = &BBI.BrCond;
-  std::vector<MachineOperand> *Cond2 = &RevCond;
+  SmallVector<MachineOperand, 4> RevCond(BBI.BrCond.begin(), BBI.BrCond.end());
+  if (TII->ReverseBranchCondition(RevCond))
+    assert(false && "Unable to reverse branch condition!");
+  SmallVector<MachineOperand, 4> *Cond1 = &BBI.BrCond;
+  SmallVector<MachineOperand, 4> *Cond2 = &RevCond;
 
   // Figure out the more profitable ordering.
   bool DoSwap = false;
@@ -1077,8 +1097,8 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind,
   MergeBlocks(BBI, *BBI1);
   MergeBlocks(BBI, *BBI2);
 
-  // If the if-converted block fallthrough or unconditionally branch into the
-  // tail block, and the tail block does not have other predecessors, then
+  // If the if-converted block falls through or unconditionally branches into
+  // the tail block, and the tail block does not have other predecessors, then
   // fold the tail block in as well. Otherwise, unless it falls through to the
   // tail, add a unconditional branch to it.
   if (TailBB) {
@@ -1107,13 +1127,15 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind,
 /// specified end with the specified condition.
 void IfConverter::PredicateBlock(BBInfo &BBI,
                                  MachineBasicBlock::iterator E,
-                                 std::vector<MachineOperand> &Cond) {
+                                 SmallVectorImpl<MachineOperand> &Cond) {
   for (MachineBasicBlock::iterator I = BBI.BB->begin(); I != E; ++I) {
     if (TII->isPredicated(I))
       continue;
     if (!TII->PredicateInstruction(I, Cond)) {
+#ifndef NDEBUG
       cerr << "Unable to predicate " << *I << "!\n";
-      abort();
+#endif
+      llvm_unreachable(0);
     }
   }
 
@@ -1128,8 +1150,10 @@ void IfConverter::PredicateBlock(BBInfo &BBI,
 /// CopyAndPredicateBlock - Copy and predicate instructions from source BB to
 /// the destination block. Skip end of block branches if IgnoreBr is true.
 void IfConverter::CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI,
-                                        std::vector<MachineOperand> &Cond,
+                                        SmallVectorImpl<MachineOperand> &Cond,
                                         bool IgnoreBr) {
+  MachineFunction &MF = *ToBBI.BB->getParent();
+
   for (MachineBasicBlock::iterator I = FromBBI.BB->begin(),
          E = FromBBI.BB->end(); I != E; ++I) {
     const TargetInstrDesc &TID = I->getDesc();
@@ -1138,14 +1162,16 @@ void IfConverter::CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI,
     if (IgnoreBr && !isPredicated && TID.isBranch())
       break;
 
-    MachineInstr *MI = I->clone();
+    MachineInstr *MI = MF.CloneMachineInstr(I);
     ToBBI.BB->insert(ToBBI.BB->end(), MI);
     ToBBI.NonPredSize++;
 
     if (!isPredicated)
       if (!TII->PredicateInstruction(MI, Cond)) {
-        cerr << "Unable to predicate " << *MI << "!\n";
-        abort();
+#ifndef NDEBUG
+        cerr << "Unable to predicate " << *I << "!\n";
+#endif
+        llvm_unreachable(0);
       }
   }
 
@@ -1159,8 +1185,7 @@ void IfConverter::CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI,
     // Fallthrough edge can't be transferred.
     if (Succ == FallThrough)
       continue;
-    if (!ToBBI.BB->isSuccessor(Succ))
-      ToBBI.BB->addSuccessor(Succ);
+    ToBBI.BB->addSuccessor(Succ);
   }
 
   std::copy(FromBBI.Predicate.begin(), FromBBI.Predicate.end(),
@@ -1200,11 +1225,10 @@ void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI) {
     if (Succ == FallThrough)
       continue;
     FromBBI.BB->removeSuccessor(Succ);
-    if (!ToBBI.BB->isSuccessor(Succ))
-      ToBBI.BB->addSuccessor(Succ);
+    ToBBI.BB->addSuccessor(Succ);
   }
 
-  // Now FromBBI always fall through to the next block!
+  // Now FromBBI always falls through to the next block!
   if (NBB && !FromBBI.BB->isSuccessor(NBB))
     FromBBI.BB->addSuccessor(NBB);