Revert r194019 to r194021, "Submit the basic port of the rest of ARM constant islands code to Mips."

It broke -Asserts build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194026 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 12 insertions, 1499 deletions

diff --git a/lib/Target/Mips/Mips16InstrInfo.td b/lib/Target/Mips/Mips16InstrInfo.td
index 9ce0139f42..725a3a76a6 100644
--- a/lib/Target/Mips/Mips16InstrInfo.td
+++ b/lib/Target/Mips/Mips16InstrInfo.td
@@ -60,11 +60,6 @@ class FRI16_ins<bits<5> op, string asmstr,
                 InstrItinClass itin>:
   FRI16_ins_base<op, asmstr, "\t$rx, $imm \t# 16 bit inst", itin>;
 
-class FRI16_TCP_ins<bits<5> _op, string asmstr,
-                    InstrItinClass itin>:
-  FRI16<_op, (outs CPU16Regs:$rx), (ins pcrel16:$imm, i32imm:$size),
-            !strconcat(asmstr, "\t$rx, $imm\t# 16 bit inst"), [], itin>;
-            
 class FRI16R_ins_base<bits<5> op, string asmstr, string asmstr2,
                      InstrItinClass itin>:
   FRI16<op, (outs), (ins CPU16Regs:$rx, simm16:$imm),
@@ -179,7 +174,7 @@ class FEXT_RI16_B_ins<bits<5> _op, string asmstr,
 
 class FEXT_RI16_TCP_ins<bits<5> _op, string asmstr,
                         InstrItinClass itin>:
-  FEXT_RI16<_op, (outs CPU16Regs:$rx), (ins pcrel16:$imm, i32imm:$size),
+  FEXT_RI16<_op, (outs CPU16Regs:$rx), (ins pcrel16:$imm),
             !strconcat(asmstr, "\t$rx, $imm"), [], itin>;
 
 class FEXT_2RI16_ins<bits<5> _op, string asmstr,
@@ -807,8 +802,6 @@ def LwRxSpImmX16: FEXT_RI16_SP_explicit_ins<0b10010, "lw", IILoad>, MayLoad{
   let Uses = [SP];
 }
 
-def LwRxPcTcp16: FRI16_TCP_ins<0b10110, "lw", IILoad>, MayLoad;
-
 def LwRxPcTcpX16: FEXT_RI16_TCP_ins<0b10110, "lw", IILoad>, MayLoad;
 //
 // Format: MOVE r32, rz MIPS16e
@@ -1876,4 +1869,3 @@ let neverHasSideEffects = 1, isNotDuplicable = 1 in
 def CONSTPOOL_ENTRY :
 MipsPseudo16<(outs), (ins cpinst_operand:$instid, cpinst_operand:$cpidx,
                       i32imm:$size), "foo", []>;
-
diff --git a/lib/Target/Mips/MipsConstantIslandPass.cpp b/lib/Target/Mips/MipsConstantIslandPass.cpp
index 8fb4538edf..3209c0c55f 100644
--- a/lib/Target/Mips/MipsConstantIslandPass.cpp
+++ b/lib/Target/Mips/MipsConstantIslandPass.cpp
@@ -27,7 +27,6 @@
 
 #include "Mips.h"
 #include "MCTargetDesc/MipsBaseInfo.h"
-#include "MipsMachineFunction.h"
 #include "MipsTargetMachine.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
@@ -43,197 +42,30 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetRegisterInfo.h"
-#include "llvm/Support/Format.h"
 #include <algorithm>
 
 using namespace llvm;
 
 STATISTIC(NumCPEs,       "Number of constpool entries");
-STATISTIC(NumSplit,      "Number of uncond branches inserted");
-#ifdef IN_PROGRESS
-STATISTIC(NumCBrFixed,   "Number of cond branches fixed");
-#endif
-STATISTIC(NumUBrFixed,   "Number of uncond branches fixed");
 
 // FIXME: This option should be removed once it has received sufficient testing.
 static cl::opt<bool>
 AlignConstantIslands("mips-align-constant-islands", cl::Hidden, cl::init(true),
           cl::desc("Align constant islands in code"));
 
-
-// Rather than do make check tests with huge amounts of code, we force
-// the test to use this amount.
-//
-static cl::opt<int> ConstantIslandsSmallOffset(
-  "mips-constant-islands-small-offset",
-  cl::init(0),
-  cl::desc("Make small offsets be this amount for testing purposes"),
-  cl::Hidden);
-
-/// UnknownPadding - Return the worst case padding that could result from
-/// unknown offset bits.  This does not include alignment padding caused by
-/// known offset bits.
-///
-/// @param LogAlign log2(alignment)
-/// @param KnownBits Number of known low offset bits.
-static inline unsigned UnknownPadding(unsigned LogAlign, unsigned KnownBits) {
-  if (KnownBits < LogAlign)
-    return (1u << LogAlign) - (1u << KnownBits);
-  return 0;
-}
-
 namespace {
-
-
   typedef MachineBasicBlock::iterator Iter;
   typedef MachineBasicBlock::reverse_iterator ReverseIter;
 
-  /// MipsConstantIslands - Due to limited PC-relative displacements, Mips
-  /// requires constant pool entries to be scattered among the instructions
-  /// inside a function.  To do this, it completely ignores the normal LLVM
-  /// constant pool; instead, it places constants wherever it feels like with
-  /// special instructions.
-  ///
-  /// The terminology used in this pass includes:
-  ///   Islands - Clumps of constants placed in the function.
-  ///   Water   - Potential places where an island could be formed.
-  ///   CPE     - A constant pool entry that has been placed somewhere, which
-  ///             tracks a list of users.
-
   class MipsConstantIslands : public MachineFunctionPass {
 
-    /// BasicBlockInfo - Information about the offset and size of a single
-    /// basic block.
-    struct BasicBlockInfo {
-      /// Offset - Distance from the beginning of the function to the beginning
-      /// of this basic block.
-      ///
-      /// Offsets are computed assuming worst case padding before an aligned
-      /// block. This means that subtracting basic block offsets always gives a
-      /// conservative estimate of the real distance which may be smaller.
-      ///
-      /// Because worst case padding is used, the computed offset of an aligned
-      /// block may not actually be aligned.
-      unsigned Offset;
-
-      /// Size - Size of the basic block in bytes.  If the block contains
-      /// inline assembly, this is a worst case estimate.
-      ///
-      /// The size does not include any alignment padding whether from the
-      /// beginning of the block, or from an aligned jump table at the end.
-      unsigned Size;
-
-      /// KnownBits - The number of low bits in Offset that are known to be
-      /// exact.  The remaining bits of Offset are an upper bound.
-      uint8_t KnownBits;
-
-      /// Unalign - When non-zero, the block contains instructions (inline asm)
-      /// of unknown size.  The real size may be smaller than Size bytes by a
-      /// multiple of 1 << Unalign.
-      uint8_t Unalign;
-
-      /// PostAlign - When non-zero, the block terminator contains a .align
-      /// directive, so the end of the block is aligned to 1 << PostAlign
-      /// bytes.
-      uint8_t PostAlign;
-
-      BasicBlockInfo() : Offset(0), Size(0), KnownBits(0), Unalign(0),
-        PostAlign(0) {}
-
-      /// Compute the number of known offset bits internally to this block.
-      /// This number should be used to predict worst case padding when
-      /// splitting the block.
-      unsigned internalKnownBits() const {
-        unsigned Bits = Unalign ? Unalign : KnownBits;
-        // If the block size isn't a multiple of the known bits, assume the
-        // worst case padding.
-        if (Size & ((1u << Bits) - 1))
-          Bits = countTrailingZeros(Size);
-        return Bits;
-      }
-
-      /// Compute the offset immediately following this block.  If LogAlign is
-      /// specified, return the offset the successor block will get if it has
-      /// this alignment.
-      unsigned postOffset(unsigned LogAlign = 0) const {
-        unsigned PO = Offset + Size;
-        return PO;
-      }
-
-      /// Compute the number of known low bits of postOffset.  If this block
-      /// contains inline asm, the number of known bits drops to the
-      /// instruction alignment.  An aligned terminator may increase the number
-      /// of know bits.
-      /// If LogAlign is given, also consider the alignment of the next block.
-      unsigned postKnownBits(unsigned LogAlign = 0) const {
-        return std::max(std::max(unsigned(PostAlign), LogAlign),
-                        internalKnownBits());
-      }
-    };
-
-    std::vector<BasicBlockInfo> BBInfo;
-
-    /// WaterList - A sorted list of basic blocks where islands could be placed
-    /// (i.e. blocks that don't fall through to the following block, due
-    /// to a return, unreachable, or unconditional branch).
-    std::vector<MachineBasicBlock*> WaterList;
-
-    /// NewWaterList - The subset of WaterList that was created since the
-    /// previous iteration by inserting unconditional branches.
-    SmallSet<MachineBasicBlock*, 4> NewWaterList;
-
-    typedef std::vector<MachineBasicBlock*>::iterator water_iterator;
-
-    /// CPUser - One user of a constant pool, keeping the machine instruction
-    /// pointer, the constant pool being referenced, and the max displacement
-    /// allowed from the instruction to the CP.  The HighWaterMark records the
-    /// highest basic block where a new CPEntry can be placed.  To ensure this
-    /// pass terminates, the CP entries are initially placed at the end of the
-    /// function and then move monotonically to lower addresses.  The
-    /// exception to this rule is when the current CP entry for a particular
-    /// CPUser is out of range, but there is another CP entry for the same
-    /// constant value in range.  We want to use the existing in-range CP
-    /// entry, but if it later moves out of range, the search for new water
-    /// should resume where it left off.  The HighWaterMark is used to record
-    /// that point.
-    struct CPUser {
-      MachineInstr *MI;
-      MachineInstr *CPEMI;
-      MachineBasicBlock *HighWaterMark;
-    private:
-      unsigned MaxDisp;
-      unsigned LongFormMaxDisp; // mips16 has 16/32 bit instructions
-                                // with different displacements
-      unsigned LongFormOpcode;
-    public:
-      bool NegOk;
-      bool IsSoImm;
-      bool KnownAlignment;
-      CPUser(MachineInstr *mi, MachineInstr *cpemi, unsigned maxdisp,
-             bool neg, bool soimm, unsigned longformmaxdisp, unsigned longformopcode)
-        : MI(mi), CPEMI(cpemi), MaxDisp(maxdisp), 
-          LongFormMaxDisp(longformmaxdisp), LongFormOpcode(longformopcode),
-          NegOk(neg), IsSoImm(soimm), KnownAlignment(false)  {
-        HighWaterMark = CPEMI->getParent();
-      }
-      /// getMaxDisp - Returns the maximum displacement supported by MI.
-      /// Correct for unknown alignment.
-      /// Conservatively subtract 2 bytes to handle weird alignment effects.
-      unsigned getMaxDisp() const {
-        unsigned xMaxDisp = ConstantIslandsSmallOffset? ConstantIslandsSmallOffset: MaxDisp;
-        return (KnownAlignment ? xMaxDisp : xMaxDisp - 2) - 2;
-      }
-      unsigned getLongFormMaxDisp() const {
-        return (KnownAlignment ? LongFormMaxDisp : LongFormMaxDisp - 2) - 2;
-      }
-      unsigned getLongFormOpcode() const {
-          return LongFormOpcode;
-      }
-    };
-
-    /// CPUsers - Keep track of all of the machine instructions that use various
-    /// constant pools and their max displacement.
-    std::vector<CPUser> CPUsers;
+  const TargetMachine &TM;
+  bool IsPIC;
+  unsigned ABI;
+  const MipsSubtarget *STI;
+  const MipsInstrInfo *TII;
+  MachineFunction *MF;
+  MachineConstantPool *MCP;
 
   /// CPEntry - One per constant pool entry, keeping the machine instruction
   /// pointer, the constpool index, and the number of CPUser's which
@@ -253,55 +85,13 @@ namespace {
   /// put in the vector of the original element, but have distinct CPIs.
   std::vector<std::vector<CPEntry> > CPEntries;
 
-  /// ImmBranch - One per immediate branch, keeping the machine instruction
-  /// pointer, conditional or unconditional, the max displacement,
-  /// and (if isCond is true) the corresponding unconditional branch
-  /// opcode.
-  struct ImmBranch {
-    MachineInstr *MI;
-    unsigned MaxDisp : 31;
-    bool isCond : 1;
-    int UncondBr;
-    ImmBranch(MachineInstr *mi, unsigned maxdisp, bool cond, int ubr)
-      : MI(mi), MaxDisp(maxdisp), isCond(cond), UncondBr(ubr) {}
-  };
-
-  /// ImmBranches - Keep track of all the immediate branch instructions.
-  ///
-  std::vector<ImmBranch> ImmBranches;
-
-  /// HasFarJump - True if any far jump instruction has been emitted during
-  /// the branch fix up pass.
-  bool HasFarJump;
-
-  const TargetMachine &TM;
-  bool IsPIC;
-  unsigned ABI;
-  const MipsSubtarget *STI;
-  const MipsInstrInfo *TII;
-  MipsFunctionInfo *MFI;
-  MachineFunction *MF;
-  MachineConstantPool *MCP;
-
-  unsigned PICLabelUId;
-  bool PrescannedForConstants;
-
-  void initPICLabelUId(unsigned UId) {
-    PICLabelUId = UId;
-  }
-
-
-  unsigned createPICLabelUId() {
-    return PICLabelUId++;
-  }
-
   public:
     static char ID;
     MipsConstantIslands(TargetMachine &tm)
       : MachineFunctionPass(ID), TM(tm),
         IsPIC(TM.getRelocationModel() == Reloc::PIC_),
         ABI(TM.getSubtarget<MipsSubtarget>().getTargetABI()),
-        STI(&TM.getSubtarget<MipsSubtarget>()), MF(0), MCP(0), PrescannedForConstants(false){}
+        STI(&TM.getSubtarget<MipsSubtarget>()), MF(0), MCP(0){}
 
     virtual const char *getPassName() const {
       return "Mips Constant Islands";
@@ -310,49 +100,6 @@ namespace {
     bool runOnMachineFunction(MachineFunction &F);
 
     void doInitialPlacement(std::vector<MachineInstr*> &CPEMIs);
-    CPEntry *findConstPoolEntry(unsigned CPI, const MachineInstr *CPEMI);
-    unsigned getCPELogAlign(const MachineInstr *CPEMI);
-    void initializeFunctionInfo(const std::vector<MachineInstr*> &CPEMIs);
-    unsigned getOffsetOf(MachineInstr *MI) const;
-    unsigned getUserOffset(CPUser&) const;
-    void dumpBBs();
-    void verify();
-
-    bool isOffsetInRange(unsigned UserOffset, unsigned TrialOffset,
-                         unsigned Disp, bool NegativeOK, bool IsSoImm = false);
-    bool isOffsetInRange(unsigned UserOffset, unsigned TrialOffset,
-                         const CPUser &U) {
-      return isOffsetInRange(UserOffset, TrialOffset,
-                             U.getMaxDisp(), U.NegOk, U.IsSoImm);
-    }
-    bool isLongFormOffsetInRange(unsigned UserOffset, unsigned TrialOffset,
-                                const CPUser &U) {
-      return isOffsetInRange(UserOffset, TrialOffset,
-                             U.getLongFormMaxDisp(), U.NegOk, U.IsSoImm);
-    }
-    void computeBlockSize(MachineBasicBlock *MBB);
-    MachineBasicBlock *splitBlockBeforeInstr(MachineInstr *MI);
-    void updateForInsertedWaterBlock(MachineBasicBlock *NewBB);
-    void adjustBBOffsetsAfter(MachineBasicBlock *BB);
-    bool decrementCPEReferenceCount(unsigned CPI, MachineInstr* CPEMI);
-    int findInRangeCPEntry(CPUser& U, unsigned UserOffset);
-    int findLongFormInRangeCPEntry(CPUser& U, unsigned UserOffset);
-    bool findAvailableWater(CPUser&U, unsigned UserOffset,
-                            water_iterator &WaterIter);
-    void createNewWater(unsigned CPUserIndex, unsigned UserOffset,
-                        MachineBasicBlock *&NewMBB);
-    bool handleConstantPoolUser(unsigned CPUserIndex);
-    void removeDeadCPEMI(MachineInstr *CPEMI);
-    bool removeUnusedCPEntries();
-    bool isCPEntryInRange(MachineInstr *MI, unsigned UserOffset,
-                          MachineInstr *CPEMI, unsigned Disp, bool NegOk,
-                          bool DoDump = false);
-    bool isWaterInRange(unsigned UserOffset, MachineBasicBlock *Water,
-                        CPUser &U, unsigned &Growth);
-    bool isBBInRange(MachineInstr *MI, MachineBasicBlock *BB, unsigned Disp);
-    bool fixupImmediateBr(ImmBranch &Br);
-    bool fixupConditionalBr(ImmBranch &Br);
-    bool fixupUnconditionalBr(ImmBranch &Br);
 
     void prescanForConstants();
 
@@ -363,19 +110,6 @@ namespace {
   char MipsConstantIslands::ID = 0;
 } // end of anonymous namespace
 
-/// print block size and offset information - debugging
-void MipsConstantIslands::dumpBBs() {
-  DEBUG({
-    for (unsigned J = 0, E = BBInfo.size(); J !=E; ++J) {
-      const BasicBlockInfo &BBI = BBInfo[J];
-      dbgs() << format("%08x BB#%u\t", BBI.Offset, J)
-             << " kb=" << unsigned(BBI.KnownBits)
-             << " ua=" << unsigned(BBI.Unalign)
-             << " pa=" << unsigned(BBI.PostAlign)
-             << format(" size=%#x\n", BBInfo[J].Size);
-    }
-  });
-}
 /// createMipsLongBranchPass - Returns a pass that converts branches to long
 /// branches.
 FunctionPass *llvm::createMipsConstantIslandPass(MipsTargetMachine &tm) {
@@ -393,15 +127,13 @@ bool MipsConstantIslands::runOnMachineFunction(MachineFunction &mf) {
     return false;
   }
   TII = (const MipsInstrInfo*)MF->getTarget().getInstrInfo();
-  MFI = MF->getInfo<MipsFunctionInfo>();
   DEBUG(dbgs() << "constant island processing " << "\n");
   //
   // will need to make predermination if there is any constants we need to
   // put in constant islands. TBD.
   //
-  if (!PrescannedForConstants) prescanForConstants();
+  prescanForConstants();
 
-  HasFarJump = false;
   // This pass invalidates liveness information when it splits basic blocks.
   MF->getRegInfo().invalidateLiveness();
 
@@ -409,66 +141,13 @@ bool MipsConstantIslands::runOnMachineFunction(MachineFunction &mf) {
   // the numbers agree with the position of the block in the function.
   MF->RenumberBlocks();
 
-  bool MadeChange = false;
-
   // Perform the initial placement of the constant pool entries.  To start with,
   // we put them all at the end of the function.
   std::vector<MachineInstr*> CPEMIs;
   if (!MCP->isEmpty())
     doInitialPlacement(CPEMIs);
 
-  /// The next UID to take is the first unused one.
-  initPICLabelUId(CPEMIs.size());
-
-  // Do the initial scan of the function, building up information about the
-  // sizes of each block, the location of all the water, and finding all of the
-  // constant pool users.
-  initializeFunctionInfo(CPEMIs);
-  CPEMIs.clear();
-  DEBUG(dumpBBs());
-
-  /// Remove dead constant pool entries.
-  MadeChange |= removeUnusedCPEntries();
-
-  // Iteratively place constant pool entries and fix up branches until there
-  // is no change.
-  unsigned NoCPIters = 0, NoBRIters = 0;
-  (void)NoBRIters;
-  while (true) {
-    DEBUG(dbgs() << "Beginning CP iteration #" << NoCPIters << '\n');
-    bool CPChange = false;
-    for (unsigned i = 0, e = CPUsers.size(); i != e; ++i)
-      CPChange |= handleConstantPoolUser(i);
-    if (CPChange && ++NoCPIters > 30)
-      report_fatal_error("Constant Island pass failed to converge!");
-    DEBUG(dumpBBs());
-
-    // Clear NewWaterList now.  If we split a block for branches, it should
-    // appear as "new water" for the next iteration of constant pool placement.
-    NewWaterList.clear();
-
-    DEBUG(dbgs() << "Beginning BR iteration #" << NoBRIters << '\n');
-    bool BRChange = false;
-#ifdef IN_PROGRESS
-    for (unsigned i = 0, e = ImmBranches.size(); i != e; ++i)
-      BRChange |= fixupImmediateBr(ImmBranches[i]);
-    if (BRChange && ++NoBRIters > 30)
-      report_fatal_error("Branch Fix Up pass failed to converge!");
-    DEBUG(dumpBBs());
-#endif
-    if (!CPChange && !BRChange)
-      break;
-    MadeChange = true;
-  }
-
-  DEBUG(dbgs() << '\n'; dumpBBs());
-
-  BBInfo.clear();
-  WaterList.clear();
-  CPUsers.clear();
-  CPEntries.clear();
-  ImmBranches.clear();
-  return MadeChange;
+  return true;
 }
 
 /// doInitialPlacement - Perform the initial placement of the constant pool
@@ -537,1165 +216,9 @@ MipsConstantIslands::doInitialPlacement(std::vector<MachineInstr*> &CPEMIs) {
   DEBUG(BB->dump());
 }
 
-/// BBHasFallthrough - Return true if the specified basic block can fallthrough
-/// into the block immediately after it.
-static bool BBHasFallthrough(MachineBasicBlock *MBB) {
-  // Get the next machine basic block in the function.
-  MachineFunction::iterator MBBI = MBB;
-  // Can't fall off end of function.
-  if (llvm::next(MBBI) == MBB->getParent()->end())
-    return false;
-
-  MachineBasicBlock *NextBB = llvm::next(MBBI);
-  for (MachineBasicBlock::succ_iterator I = MBB->succ_begin(),
-       E = MBB->succ_end(); I != E; ++I)
-    if (*I == NextBB)
-      return true;
-
-  return false;
-}
-
-/// findConstPoolEntry - Given the constpool index and CONSTPOOL_ENTRY MI,
-/// look up the corresponding CPEntry.
-MipsConstantIslands::CPEntry
-*MipsConstantIslands::findConstPoolEntry(unsigned CPI,
-                                        const MachineInstr *CPEMI) {
-  std::vector<CPEntry> &CPEs = CPEntries[CPI];
-  // Number of entries per constpool index should be small, just do a
-  // linear search.
-  for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
-    if (CPEs[i].CPEMI == CPEMI)
-      return &CPEs[i];
-  }
-  return NULL;
-}
-
-/// getCPELogAlign - Returns the required alignment of the constant pool entry
-/// represented by CPEMI.  Alignment is measured in log2(bytes) units.
-unsigned MipsConstantIslands::getCPELogAlign(const MachineInstr *CPEMI) {
-  assert(CPEMI && CPEMI->getOpcode() == Mips::CONSTPOOL_ENTRY);
-
-  // Everything is 4-byte aligned unless AlignConstantIslands is set.
-  if (!AlignConstantIslands)
-    return 2;
-
-  unsigned CPI = CPEMI->getOperand(1).getIndex();
-  assert(CPI < MCP->getConstants().size() && "Invalid constant pool index.");
-  unsigned Align = MCP->getConstants()[CPI].getAlignment();
-  assert(isPowerOf2_32(Align) && "Invalid CPE alignment");
-  return Log2_32(Align);
-}
-
-/// initializeFunctionInfo - Do the initial scan of the function, building up
-/// information about the sizes of each block, the location of all the water,
-/// and finding all of the constant pool users.
-void MipsConstantIslands::
-initializeFunctionInfo(const std::vector<MachineInstr*> &CPEMIs) {
-  BBInfo.clear();
-  BBInfo.resize(MF->getNumBlockIDs());
-
-  // First thing, compute the size of all basic blocks, and see if the function
-  // has any inline assembly in it. If so, we have to be conservative about
-  // alignment assumptions, as we don't know for sure the size of any
-  // instructions in the inline assembly.
-  for (MachineFunction::iterator I = MF->begin(), E = MF->end(); I != E; ++I)
-    computeBlockSize(I);
-
-  // The known bits of the entry block offset are determined by the function
-  // alignment.
-  BBInfo.front().KnownBits = MF->getAlignment();
-
-  // Compute block offsets.
-  adjustBBOffsetsAfter(MF->begin());
-
-  // Now go back through the instructions and build up our data structures.
-  for (MachineFunction::iterator MBBI = MF->begin(), E = MF->end();
-       MBBI != E; ++MBBI) {
-    MachineBasicBlock &MBB = *MBBI;
-
-    // If this block doesn't fall through into the next MBB, then this is
-    // 'water' that a constant pool island could be placed.
-    if (!BBHasFallthrough(&MBB))
-      WaterList.push_back(&MBB);
-    for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end();
-         I != E; ++I) {
-      if (I->isDebugValue())
-        continue;
-
-      int Opc = I->getOpcode();
-      if (I->isBranch()) {
-        bool isCond = false;
-        unsigned Bits = 0;
-        unsigned Scale = 1;
-        int UOpc = Opc;
-
-        switch (Opc) {
-        default:
-          continue;  // Ignore other JT branches
-#ifdef IN_PROGRESS
-        case ARM::t2BR_JT:
-          T2JumpTables.push_back(I);
-          continue;   // Does not get an entry in ImmBranches
-        case ARM::Bcc:
-          isCond = true;
-          UOpc = ARM::B;
-          // Fallthrough
-        case ARM::B:
-          Bits = 24;
-          Scale = 4;
-          break;
-        case ARM::tBcc:
-          isCond = true;
-          UOpc = ARM::tB;
-          Bits = 8;
-          Scale = 2;
-          break;
-        case ARM::tB:
-          Bits = 11;
-          Scale = 2;
-          break;
-        case ARM::t2Bcc:
-          isCond = true;
-          UOpc = ARM::t2B;
-          Bits = 20;
-          Scale = 2;
-          break;
-        case ARM::t2B:
-          Bits = 24;
-          Scale = 2;
-          break;
-#endif
-        }
-        // Record this immediate branch.
-        unsigned MaxOffs = ((1 << (Bits-1))-1) * Scale;
-        ImmBranches.push_back(ImmBranch(I, MaxOffs, isCond, UOpc));
-
-      }
-
-
-      if (Opc == Mips::CONSTPOOL_ENTRY)
-        continue;
-
-
-      // Scan the instructions for constant pool operands.
-      for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op)
-        if (I->getOperand(op).isCPI()) {
-
-          // We found one.  The addressing mode tells us the max displacement
-          // from the PC that this instruction permits.
-
-          // Basic size info comes from the TSFlags field.
-          unsigned Bits = 0;
-          unsigned Scale = 1;
-          bool NegOk = false;
-          bool IsSoImm = false;
-          unsigned LongFormBits = 0;
-          unsigned LongFormScale = 0;
-          unsigned LongFormOpcode = 0;
-          switch (Opc) {
-          default:
-            llvm_unreachable("Unknown addressing mode for CP reference!");
-          case Mips::LwRxPcTcp16:
-            Bits = 8;
-            Scale = 2;
-            LongFormOpcode = Mips::LwRxPcTcpX16;
-            break;
-          case Mips::LwRxPcTcpX16:
-            Bits = 16;
-            Scale = 2;
-            break;
-#ifdef IN_PROGRESS
-          // Taking the address of a CP entry.
-          case ARM::LEApcrel:
-            // This takes a SoImm, which is 8 bit immediate rotated. We'll
-            // pretend the maximum offset is 255 * 4. Since each instruction
-            // 4 byte wide, this is always correct. We'll check for other
-            // displacements that fits in a SoImm as well.
-            Bits = 8;
-            Scale = 4;
-            NegOk = true;
-            IsSoImm = true;
-            break;
-          case ARM::t2LEApcrel:
-            Bits = 12;
-            NegOk = true;
-            break;
-          case ARM::tLEApcrel:
-            Bits = 8;
-            Scale = 4;
-            break;
-
-          case ARM::LDRBi12:
-          case ARM::LDRi12:
-          case ARM::LDRcp:
-          case ARM::t2LDRpci:
-            Bits = 12;  // +-offset_12
-            NegOk = true;
-            break;
-
-          case ARM::tLDRpci:
-            Bits = 8;
-            Scale = 4;  // +(offset_8*4)
-            break;
-
-          case ARM::VLDRD:
-          case ARM::VLDRS:
-            Bits = 8;
-            Scale = 4;  // +-(offset_8*4)
-            NegOk = true;
-            break;
-#endif
-          }
-          // Remember that this is a user of a CP entry.
-          unsigned CPI = I->getOperand(op).getIndex();
-          MachineInstr *CPEMI = CPEMIs[CPI];
-          unsigned MaxOffs = ((1 << Bits)-1) * Scale;
-          unsigned LongFormMaxOffs = ((1 << LongFormBits)-1) * LongFormScale;
-          CPUsers.push_back(CPUser(I, CPEMI, MaxOffs, NegOk, IsSoImm, LongFormMaxOffs,
-                                   LongFormOpcode));
-
-          // Increment corresponding CPEntry reference count.
-          CPEntry *CPE = findConstPoolEntry(CPI, CPEMI);
-          assert(CPE && "Cannot find a corresponding CPEntry!");
-          CPE->RefCount++;
-
-          // Instructions can only use one CP entry, don't bother scanning the
-          // rest of the operands.
-          break;
-
-        }
-
-    }
-  }
-
-}
-
-/// computeBlockSize - Compute the size and some alignment information for MBB.
-/// This function updates BBInfo directly.
-void MipsConstantIslands::computeBlockSize(MachineBasicBlock *MBB) {
-  BasicBlockInfo &BBI = BBInfo[MBB->getNumber()];
-  BBI.Size = 0;
-  BBI.Unalign = 0;
-  BBI.PostAlign = 0;
-
-  for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end(); I != E;
-       ++I)
-    BBI.Size += TII->GetInstSizeInBytes(I);
-
-}
-
-/// getOffsetOf - Return the current offset of the specified machine instruction
-/// from the start of the function.  This offset changes as stuff is moved
-/// around inside the function.
-unsigned MipsConstantIslands::getOffsetOf(MachineInstr *MI) const {
-  MachineBasicBlock *MBB = MI->getParent();
-
-  // The offset is composed of two things: the sum of the sizes of all MBB's
-  // before this instruction's block, and the offset from the start of the block
-  // it is in.
-  unsigned Offset = BBInfo[MBB->getNumber()].Offset;
-
-  // Sum instructions before MI in MBB.
-  for (MachineBasicBlock::iterator I = MBB->begin(); &*I != MI; ++I) {
-    assert(I != MBB->end() && "Didn't find MI in its own basic block?");
-    Offset += TII->GetInstSizeInBytes(I);
-  }
-  return Offset;
-}
-
-/// CompareMBBNumbers - Little predicate function to sort the WaterList by MBB
-/// ID.
-static bool CompareMBBNumbers(const MachineBasicBlock *LHS,
-                              const MachineBasicBlock *RHS) {
-  return LHS->getNumber() < RHS->getNumber();
-}
-
-/// updateForInsertedWaterBlock - When a block is newly inserted into the
-/// machine function, it upsets all of the block numbers.  Renumber the blocks
-/// and update the arrays that parallel this numbering.
-void MipsConstantIslands::updateForInsertedWaterBlock(MachineBasicBlock *NewBB) {
-  // Renumber the MBB's to keep them consecutive.
-  NewBB->getParent()->RenumberBlocks(NewBB);
-
-  // Insert an entry into BBInfo to align it properly with the (newly
-  // renumbered) block numbers.
-  BBInfo.insert(BBInfo.begin() + NewBB->getNumber(), BasicBlockInfo());
-
-  // Next, update WaterList.  Specifically, we need to add NewMBB as having
-  // available water after it.
-  water_iterator IP =
-    std::lower_bound(WaterList.begin(), WaterList.end(), NewBB,
-                     CompareMBBNumbers);
-  WaterList.insert(IP, NewBB);
-}
-
-/// getUserOffset - Compute the offset of U.MI as seen by the hardware
-/// displacement computation.  Update U.KnownAlignment to match its current
-/// basic block location.
-unsigned MipsConstantIslands::getUserOffset(CPUser &U) const {
-  unsigned UserOffset = getOffsetOf(U.MI);
-  const BasicBlockInfo &BBI = BBInfo[U.MI->getParent()->getNumber()];
-  unsigned KnownBits = BBI.internalKnownBits();
-
-  // The value read from PC is offset from the actual instruction address.
-#ifdef IN_PROGRESS
-  UserOffset += (isThumb ? 4 : 8);
-#endif
-
-  // Because of inline assembly, we may not know the alignment (mod 4) of U.MI.
-  // Make sure U.getMaxDisp() returns a constrained range.
-  U.KnownAlignment = (KnownBits >= 2);
-
-  // On Thumb, offsets==2 mod 4 are rounded down by the hardware for
-  // purposes of the displacement computation; compensate for that here.
-  // For unknown alignments, getMaxDisp() constrains the range instead.
-#ifdef IN_PROGRESS
-  if (isThumb && U.KnownAlignment)
-    UserOffset &= ~3u;
-#endif
-
-  return UserOffset;
-}
-
-/// Split the basic block containing MI into two blocks, which are joined by
-/// an unconditional branch.  Update data structures and renumber blocks to
-/// account for this change and returns the newly created block.
-MachineBasicBlock *MipsConstantIslands::splitBlockBeforeInstr(MachineInstr *MI) {
-  MachineBasicBlock *OrigBB = MI->getParent();
-
-  // Create a new MBB for the code after the OrigBB.
-  MachineBasicBlock *NewBB =
-    MF->CreateMachineBasicBlock(OrigBB->getBasicBlock());
-  MachineFunction::iterator MBBI = OrigBB; ++MBBI;
-  MF->insert(MBBI, NewBB);
-
-  // Splice the instructions starting with MI over to NewBB.
-  NewBB->splice(NewBB->end(), OrigBB, MI, OrigBB->end());
-
-  // Add an unconditional branch from OrigBB to NewBB.
-  // Note the new unconditional branch is not being recorded.
-  // There doesn't seem to be meaningful DebugInfo available; this doesn't
-  // correspond to anything in the source.
-  BuildMI(OrigBB, DebugLoc(), TII->get(Mips::BimmX16)).addMBB(NewBB);
-#ifdef IN_PROGRESS
-  unsigned Opc = isThumb ? (isThumb2 ? ARM::t2B : ARM::tB) : ARM::B;
-  if (!isThumb)
-    BuildMI(OrigBB, DebugLoc(), TII->get(Opc)).addMBB(NewBB);
-  else
-    BuildMI(OrigBB, DebugLoc(), TII->get(Opc)).addMBB(NewBB)
-            .addImm(ARMCC::AL).addReg(0);
-#endif
-  ++NumSplit;
-
-  // Update the CFG.  All succs of OrigBB are now succs of NewBB.
-  NewBB->transferSuccessors(OrigBB);
-
-  // OrigBB branches to NewBB.
-  OrigBB->addSuccessor(NewBB);
-
-  // Update internal data structures to account for the newly inserted MBB.
-  // This is almost the same as updateForInsertedWaterBlock, except that
-  // the Water goes after OrigBB, not NewBB.
-  MF->RenumberBlocks(NewBB);
-
-  // Insert an entry into BBInfo to align it properly with the (newly
-  // renumbered) block numbers.
-  BBInfo.insert(BBInfo.begin() + NewBB->getNumber(), BasicBlockInfo());
-
-  // Next, update WaterList.  Specifically, we need to add OrigMBB as having
-  // available water after it (but not if it's already there, which happens
-  // when splitting before a conditional branch that is followed by an
-  // unconditional branch - in that case we want to insert NewBB).
-  water_iterator IP =
-    std::lower_bound(WaterList.begin(), WaterList.end(), OrigBB,
-                     CompareMBBNumbers);
-  MachineBasicBlock* WaterBB = *IP;
-  if (WaterBB == OrigBB)
-    WaterList.insert(llvm::next(IP), NewBB);
-  else
-    WaterList.insert(IP, OrigBB);
-  NewWaterList.insert(OrigBB);
-
-  // Figure out how large the OrigBB is.  As the first half of the original
-  // block, it cannot contain a tablejump.  The size includes
-  // the new jump we added.  (It should be possible to do this without
-  // recounting everything, but it's very confusing, and this is rarely
-  // executed.)
-  computeBlockSize(OrigBB);
-
-  // Figure out how large the NewMBB is.  As the second half of the original
-  // block, it may contain a tablejump.
-  computeBlockSize(NewBB);
-
-  // All BBOffsets following these blocks must be modified.
-  adjustBBOffsetsAfter(OrigBB);
-
-  return NewBB;
-}
-
-#ifndef NDEBUG
-
-
-/// isOffsetInRange - Checks whether UserOffset (the location of a constant pool
-/// reference) is within MaxDisp of TrialOffset (a proposed location of a
-/// constant pool entry).
-/// UserOffset is computed by getUserOffset above to include PC adjustments. If
-/// the mod 4 alignment of UserOffset is not known, the uncertainty must be
-/// subtracted from MaxDisp instead. CPUser::getMaxDisp() does that.
-bool MipsConstantIslands::isOffsetInRange(unsigned UserOffset,
-                                         unsigned TrialOffset, unsigned MaxDisp,
-                                         bool NegativeOK, bool IsSoImm) {
-  if (UserOffset <= TrialOffset) {
-    // User before the Trial.
-    if (TrialOffset - UserOffset <= MaxDisp)
-      return true;
-    // FIXME: Make use full range of soimm values.
-  } else if (NegativeOK) {
-    if (UserOffset - TrialOffset <= MaxDisp)
-      return true;
-    // FIXME: Make use full range of soimm values.
-  }
-  return false;
-}
-
-/// isWaterInRange - Returns true if a CPE placed after the specified
-/// Water (a basic block) will be in range for the specific MI.
-///
-/// Compute how much the function will grow by inserting a CPE after Water.
-bool MipsConstantIslands::isWaterInRange(unsigned UserOffset,
-                                        MachineBasicBlock* Water, CPUser &U,
-                                        unsigned &Growth) {
-  unsigned CPELogAlign = getCPELogAlign(U.CPEMI);
-  unsigned CPEOffset = BBInfo[Water->getNumber()].postOffset(CPELogAlign);
-  unsigned NextBlockOffset, NextBlockAlignment;
-  MachineFunction::const_iterator NextBlock = Water;
-  if (++NextBlock == MF->end()) {
-    NextBlockOffset = BBInfo[Water->getNumber()].postOffset();
-    NextBlockAlignment = 0;
-  } else {
-    NextBlockOffset = BBInfo[NextBlock->getNumber()].Offset;
-    NextBlockAlignment = NextBlock->getAlignment();
-  }
-  unsigned Size = U.CPEMI->getOperand(2).getImm();
-  unsigned CPEEnd = CPEOffset + Size;
-
-  // The CPE may be able to hide in the alignment padding before the next
-  // block. It may also cause more padding to be required if it is more aligned
-  // that the next block.
-  if (CPEEnd > NextBlockOffset) {
-    Growth = CPEEnd - NextBlockOffset;
-    // Compute the padding that would go at the end of the CPE to align the next
-    // block.
-    Growth += OffsetToAlignment(CPEEnd, 1u << NextBlockAlignment);
-
-    // If the CPE is to be inserted before the instruction, that will raise
-    // the offset of the instruction. Also account for unknown alignment padding
-    // in blocks between CPE and the user.
-    if (CPEOffset < UserOffset)
-      UserOffset += Growth + UnknownPadding(MF->getAlignment(), CPELogAlign);
-  } else
-    // CPE fits in existing padding.
-    Growth = 0;
-
-  return isOffsetInRange(UserOffset, CPEOffset, U);
-}
-
-/// isCPEntryInRange - Returns true if the distance between specific MI and
-/// specific ConstPool entry instruction can fit in MI's displacement field.
-bool MipsConstantIslands::isCPEntryInRange(MachineInstr *MI, unsigned UserOffset,
-                                      MachineInstr *CPEMI, unsigned MaxDisp,
-                                      bool NegOk, bool DoDump) {
-  unsigned CPEOffset  = getOffsetOf(CPEMI);
-
-  if (DoDump) {
-    DEBUG({
-      unsigned Block = MI->getParent()->getNumber();
-      const BasicBlockInfo &BBI = BBInfo[Block];
-      dbgs() << "User of CPE#" << CPEMI->getOperand(0).getImm()
-             << " max delta=" << MaxDisp
-             << format(" insn address=%#x", UserOffset)
-             << " in BB#" << Block << ": "
-             << format("%#x-%x\t", BBI.Offset, BBI.postOffset()) << *MI
-             << format("CPE address=%#x offset=%+d: ", CPEOffset,
-                       int(CPEOffset-UserOffset));
-    });
-  }
-
-  return isOffsetInRange(UserOffset, CPEOffset, MaxDisp, NegOk);
-}
-
-/// BBIsJumpedOver - Return true of the specified basic block's only predecessor
-/// unconditionally branches to its only successor.
-static bool BBIsJumpedOver(MachineBasicBlock *MBB) {
-  if (MBB->pred_size() != 1 || MBB->succ_size() != 1)
-    return false;
-
-#ifdef IN_PROGRESS
-  MachineBasicBlock *Succ = *MBB->succ_begin();
-  MachineBasicBlock *Pred = *MBB->pred_begin();
-  MachineInstr *PredMI = &Pred->back();
-  if (PredMI->getOpcode() == ARM::B || PredMI->getOpcode() == ARM::tB
-      || PredMI->getOpcode() == ARM::t2B)
-    return PredMI->getOperand(0).getMBB() == Succ;
-#endif
-  return false;
-}
-#endif // NDEBUG
-
-void MipsConstantIslands::adjustBBOffsetsAfter(MachineBasicBlock *BB) {
-  unsigned BBNum = BB->getNumber();
-  for(unsigned i = BBNum + 1, e = MF->getNumBlockIDs(); i < e; ++i) {
-    // Get the offset and known bits at the end of the layout predecessor.
-    // Include the alignment of the current block.
-    unsigned Offset = BBInfo[i - 1].postOffset();
-    BBInfo[i].Offset = Offset;
-  }
-}
-
-/// decrementCPEReferenceCount - find the constant pool entry with index CPI
-/// and instruction CPEMI, and decrement its refcount.  If the refcount
-/// becomes 0 remove the entry and instruction.  Returns true if we removed
-/// the entry, false if we didn't.
-
-bool MipsConstantIslands::decrementCPEReferenceCount(unsigned CPI,
-                                                    MachineInstr *CPEMI) {
-  // Find the old entry. Eliminate it if it is no longer used.
-  CPEntry *CPE = findConstPoolEntry(CPI, CPEMI);
-  assert(CPE && "Unexpected!");
-  if (--CPE->RefCount == 0) {
-    removeDeadCPEMI(CPEMI);
-    CPE->CPEMI = NULL;
-    --NumCPEs;
-    return true;
-  }
-  return false;
-}
-
-/// LookForCPEntryInRange - see if the currently referenced CPE is in range;
-/// if not, see if an in-range clone of the CPE is in range, and if so,
-/// change the data structures so the user references the clone.  Returns:
-/// 0 = no existing entry found
-/// 1 = entry found, and there were no code insertions or deletions
-/// 2 = entry found, and there were code insertions or deletions
-int MipsConstantIslands::findInRangeCPEntry(CPUser& U, unsigned UserOffset)
-{
-  MachineInstr *UserMI = U.MI;
-  MachineInstr *CPEMI  = U.CPEMI;
-
-  // Check to see if the CPE is already in-range.
-  if (isCPEntryInRange(UserMI, UserOffset, CPEMI, U.getMaxDisp(), U.NegOk,
-                       true)) {
-    DEBUG(dbgs() << "In range\n");
-    return 1;
-  }
-
-  // No.  Look for previously created clones of the CPE that are in range.
-  unsigned CPI = CPEMI->getOperand(1).getIndex();
-  std::vector<CPEntry> &CPEs = CPEntries[CPI];
-  for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
-    // We already tried this one
-    if (CPEs[i].CPEMI == CPEMI)
-      continue;
-    // Removing CPEs can leave empty entries, skip
-    if (CPEs[i].CPEMI == NULL)
-      continue;
-    if (isCPEntryInRange(UserMI, UserOffset, CPEs[i].CPEMI, U.getMaxDisp(),
-                     U.NegOk)) {
-      DEBUG(dbgs() << "Replacing CPE#" << CPI << " with CPE#"
-                   << CPEs[i].CPI << "\n");
-      // Point the CPUser node to the replacement
-      U.CPEMI = CPEs[i].CPEMI;
-      // Change the CPI in the instruction operand to refer to the clone.
-      for (unsigned j = 0, e = UserMI->getNumOperands(); j != e; ++j)
-        if (UserMI->getOperand(j).isCPI()) {
-          UserMI->getOperand(j).setIndex(CPEs[i].CPI);
-          break;
-        }
-      // Adjust the refcount of the clone...
-      CPEs[i].RefCount++;
-      // ...and the original.  If we didn't remove the old entry, none of the
-      // addresses changed, so we don't need another pass.
-      return decrementCPEReferenceCount(CPI, CPEMI) ? 2 : 1;
-    }
-  }
-  return 0;
-}
-
-/// LookForCPEntryInRange - see if the currently referenced CPE is in range;
-/// This version checks if the longer form of the instruction can be used to
-/// to satisfy things.
-/// if not, see if an in-range clone of the CPE is in range, and if so,
-/// change the data structures so the user references the clone.  Returns:
-/// 0 = no existing entry found
-/// 1 = entry found, and there were no code insertions or deletions
-/// 2 = entry found, and there were code insertions or deletions
-int MipsConstantIslands::findLongFormInRangeCPEntry(CPUser& U, unsigned UserOffset)
-{
-  MachineInstr *UserMI = U.MI;
-  MachineInstr *CPEMI  = U.CPEMI;
-
-  // Check to see if the CPE is already in-range.
-  if (isCPEntryInRange(UserMI, UserOffset, CPEMI, U.getLongFormMaxDisp(), U.NegOk,
-                       true)) {
-    DEBUG(dbgs() << "In range\n");
-    UserMI->setDesc(TII->get(U.getLongFormOpcode()));
-    return 2;  // instruction is longer length now
-  }
-
-  // No.  Look for previously created clones of the CPE that are in range.
-  unsigned CPI = CPEMI->getOperand(1).getIndex();
-  std::vector<CPEntry> &CPEs = CPEntries[CPI];
-  for (unsigned i = 0, e = CPEs.size(); i != e; ++i) {
-    // We already tried this one
-    if (CPEs[i].CPEMI == CPEMI)
-      continue;
-    // Removing CPEs can leave empty entries, skip
-    if (CPEs[i].CPEMI == NULL)
-      continue;
-    if (isCPEntryInRange(UserMI, UserOffset, CPEs[i].CPEMI, U.getLongFormMaxDisp(),
-                     U.NegOk)) {
-      DEBUG(dbgs() << "Replacing CPE#" << CPI << " with CPE#"
-                   << CPEs[i].CPI << "\n");
-      // Point the CPUser node to the replacement
-      U.CPEMI = CPEs[i].CPEMI;
-      // Change the CPI in the instruction operand to refer to the clone.
-      for (unsigned j = 0, e = UserMI->getNumOperands(); j != e; ++j)
-        if (UserMI->getOperand(j).isCPI()) {
-          UserMI->getOperand(j).setIndex(CPEs[i].CPI);
-          break;
-        }
-      // Adjust the refcount of the clone...
-      CPEs[i].RefCount++;
-      // ...and the original.  If we didn't remove the old entry, none of the
-      // addresses changed, so we don't need another pass.
-      return decrementCPEReferenceCount(CPI, CPEMI) ? 2 : 1;
-    }
-  }
-  return 0;
-}
-
-/// getUnconditionalBrDisp - Returns the maximum displacement that can fit in
-/// the specific unconditional branch instruction.
-static inline unsigned getUnconditionalBrDisp(int Opc) {
-#ifdef IN_PROGRESS
-  switch (Opc) {
-  case ARM::tB:
-    return ((1<<10)-1)*2;
-  case ARM::t2B:
-    return ((1<<23)-1)*2;
-  default:
-    break;
-  }
-#endif
-  return ((1<<23)-1)*4;
-}
-
-/// findAvailableWater - Look for an existing entry in the WaterList in which
-/// we can place the CPE referenced from U so it's within range of U's MI.
-/// Returns true if found, false if not.  If it returns true, WaterIter
-/// is set to the WaterList entry.  For Thumb, prefer water that will not
-/// introduce padding to water that will.  To ensure that this pass
-/// terminates, the CPE location for a particular CPUser is only allowed to
-/// move to a lower address, so search backward from the end of the list and
-/// prefer the first water that is in range.
-bool MipsConstantIslands::findAvailableWater(CPUser &U, unsigned UserOffset,
-                                      water_iterator &WaterIter) {
-  if (WaterList.empty())
-    return false;
-
-  unsigned BestGrowth = ~0u;
-  for (water_iterator IP = prior(WaterList.end()), B = WaterList.begin();;
-       --IP) {
-    MachineBasicBlock* WaterBB = *IP;
-    // Check if water is in range and is either at a lower address than the
-    // current "high water mark" or a new water block that was created since
-    // the previous iteration by inserting an unconditional branch.  In the
-    // latter case, we want to allow resetting the high water mark back to
-    // this new water since we haven't seen it before.  Inserting branches
-    // should be relatively uncommon and when it does happen, we want to be
-    // sure to take advantage of it for all the CPEs near that block, so that
-    // we don't insert more branches than necessary.
-    unsigned Growth;
-    if (isWaterInRange(UserOffset, WaterBB, U, Growth) &&
-        (WaterBB->getNumber() < U.HighWaterMark->getNumber() ||
-         NewWaterList.count(WaterBB)) && Growth < BestGrowth) {
-      // This is the least amount of required padding seen so far.
-      BestGrowth = Growth;
-      WaterIter = IP;
-      DEBUG(dbgs() << "Found water after BB#" << WaterBB->getNumber()
-                   << " Growth=" << Growth << '\n');
-
-      // Keep looking unless it is perfect.
-      if (BestGrowth == 0)
-        return true;
-    }
-    if (IP == B)
-      break;
-  }
-  return BestGrowth != ~0u;
-}
-
-/// createNewWater - No existing WaterList entry will work for
-/// CPUsers[CPUserIndex], so create a place to put the CPE.  The end of the
-/// block is used if in range, and the conditional branch munged so control
-/// flow is correct.  Otherwise the block is split to create a hole with an
-/// unconditional branch around it.  In either case NewMBB is set to a
-/// block following which the new island can be inserted (the WaterList
-/// is not adjusted).
-void MipsConstantIslands::createNewWater(unsigned CPUserIndex,
-                                        unsigned UserOffset,
-                                        MachineBasicBlock *&NewMBB) {
-  CPUser &U = CPUsers[CPUserIndex];
-  MachineInstr *UserMI = U.MI;
-  MachineInstr *CPEMI  = U.CPEMI;
-  unsigned CPELogAlign = getCPELogAlign(CPEMI);
-  MachineBasicBlock *UserMBB = UserMI->getParent();
-  const BasicBlockInfo &UserBBI = BBInfo[UserMBB->getNumber()];
-
-  // If the block does not end in an unconditional branch already, and if the
-  // end of the block is within range, make new water there.  (The addition
-  // below is for the unconditional branch we will be adding: 4 bytes on ARM +
-  // Thumb2, 2 on Thumb1.
-  if (BBHasFallthrough(UserMBB)) {
-    // Size of branch to insert.
-#ifdef IN_PROGRESS
-    unsigned Delta = isThumb1 ? 2 : 4;
-#else
-    unsigned Delta = 4;
-#endif
-    // Compute the offset where the CPE will begin.
-    unsigned CPEOffset = UserBBI.postOffset(CPELogAlign) + Delta;
-
-    if (isOffsetInRange(UserOffset, CPEOffset, U)) {
-      DEBUG(dbgs() << "Split at end of BB#" << UserMBB->getNumber()
-            << format(", expected CPE offset %#x\n", CPEOffset));
-      NewMBB = llvm::next(MachineFunction::iterator(UserMBB));
-      // Add an unconditional branch from UserMBB to fallthrough block.  Record
-      // it for branch lengthening; this new branch will not get out of range,
-      // but if the preceding conditional branch is out of range, the targets
-      // will be exchanged, and the altered branch may be out of range, so the
-      // machinery has to know about it.
-#ifdef IN_PROGRESS
-      int UncondBr = isThumb ? ((isThumb2) ? ARM::t2B : ARM::tB) : ARM::B;
-      if (!isThumb)
-        BuildMI(UserMBB, DebugLoc(), TII->get(UncondBr)).addMBB(NewMBB);
-      else
-        BuildMI(UserMBB, DebugLoc(), TII->get(UncondBr)).addMBB(NewMBB)
-          .addImm(ARMCC::AL).addReg(0);
-#else
-      int UncondBr = 1;
-#endif
-      unsigned MaxDisp = getUnconditionalBrDisp(UncondBr);
-      ImmBranches.push_back(ImmBranch(&UserMBB->back(),
-                                      MaxDisp, false, UncondBr));
-      BBInfo[UserMBB->getNumber()].Size += Delta;
-      adjustBBOffsetsAfter(UserMBB);
-      return;
-    }
-  }
-
-  // What a big block.  Find a place within the block to split it.  This is a
-  // little tricky on Thumb1 since instructions are 2 bytes and constant pool
-  // entries are 4 bytes: if instruction I references island CPE, and
-  // instruction I+1 references CPE', it will not work well to put CPE as far
-  // forward as possible, since then CPE' cannot immediately follow it (that
-  // location is 2 bytes farther away from I+1 than CPE was from I) and we'd
-  // need to create a new island.  So, we make a first guess, then walk through
-  // the instructions between the one currently being looked at and the
-  // possible insertion point, and make sure any other instructions that
-  // reference CPEs will be able to use the same island area; if not, we back
-  // up the insertion point.
-
-  // Try to split the block so it's fully aligned.  Compute the latest split
-  // point where we can add a 4-byte branch instruction, and then align to
-  // LogAlign which is the largest possible alignment in the function.
-  unsigned LogAlign = MF->getAlignment();
-  assert(LogAlign >= CPELogAlign && "Over-aligned constant pool entry");
-  unsigned KnownBits = UserBBI.internalKnownBits();
-  unsigned UPad = UnknownPadding(LogAlign, KnownBits);
-  unsigned BaseInsertOffset = UserOffset + U.getMaxDisp() - UPad;
-  DEBUG(dbgs() << format("Split in middle of big block before %#x",
-                         BaseInsertOffset));
-
-  // The 4 in the following is for the unconditional branch we'll be inserting
-  // (allows for long branch on Thumb1).  Alignment of the island is handled
-  // inside isOffsetInRange.
-  BaseInsertOffset -= 4;
-
-  DEBUG(dbgs() << format(", adjusted to %#x", BaseInsertOffset)
-               << " la=" << LogAlign
-               << " kb=" << KnownBits
-               << " up=" << UPad << '\n');
-
-  // This could point off the end of the block if we've already got constant
-  // pool entries following this block; only the last one is in the water list.
-  // Back past any possible branches (allow for a conditional and a maximally
-  // long unconditional).
-  if (BaseInsertOffset + 8 >= UserBBI.postOffset()) {
-    BaseInsertOffset = UserBBI.postOffset() - UPad - 8;
-    DEBUG(dbgs() << format("Move inside block: %#x\n", BaseInsertOffset));
-  }
-  unsigned EndInsertOffset = BaseInsertOffset + 4 + UPad +
-    CPEMI->getOperand(2).getImm();
-  MachineBasicBlock::iterator MI = UserMI;
-  ++MI;
-  unsigned CPUIndex = CPUserIndex+1;
-  unsigned NumCPUsers = CPUsers.size();
-  MachineInstr *LastIT = 0;
-  for (unsigned Offset = UserOffset+TII->GetInstSizeInBytes(UserMI);
-       Offset < BaseInsertOffset;
-       Offset += TII->GetInstSizeInBytes(MI),
-       MI = llvm::next(MI)) {
-    assert(MI != UserMBB->end() && "Fell off end of block");
-    if (CPUIndex < NumCPUsers && CPUsers[CPUIndex].MI == MI) {
-      CPUser &U = CPUsers[CPUIndex];
-      if (!isOffsetInRange(Offset, EndInsertOffset, U)) {
-        // Shift intertion point by one unit of alignment so it is within reach.
-        BaseInsertOffset -= 1u << LogAlign;
-        EndInsertOffset  -= 1u << LogAlign;
-      }
-      // This is overly conservative, as we don't account for CPEMIs being
-      // reused within the block, but it doesn't matter much.  Also assume CPEs
-      // are added in order with alignment padding.  We may eventually be able
-      // to pack the aligned CPEs better.
-      EndInsertOffset += U.CPEMI->getOperand(2).getImm();
-      CPUIndex++;
-    }
-#ifdef IN_PROGRESS
-    // Remember the last IT instruction.
-    if (MI->getOpcode() == ARM::t2IT)
-      LastIT = MI;
-#endif
-  }
-
-  --MI;
-
-  // Avoid splitting an IT block.
-  if (LastIT) {
-#ifdef IN_PROGRESS
-    unsigned PredReg = 0;
-    ARMCC::CondCodes CC = getITInstrPredicate(MI, PredReg);
-    if (CC != ARMCC::AL)
-      MI = LastIT;
-#endif
-  }
-  NewMBB = splitBlockBeforeInstr(MI);
-}
-
-/// handleConstantPoolUser - Analyze the specified user, checking to see if it
-/// is out-of-range.  If so, pick up the constant pool value and move it some
-/// place in-range.  Return true if we changed any addresses (thus must run
-/// another pass of branch lengthening), false otherwise.
-bool MipsConstantIslands::handleConstantPoolUser(unsigned CPUserIndex) {
-  CPUser &U = CPUsers[CPUserIndex];
-  MachineInstr *UserMI = U.MI;
-  MachineInstr *CPEMI  = U.CPEMI;
-  unsigned CPI = CPEMI->getOperand(1).getIndex();
-  unsigned Size = CPEMI->getOperand(2).getImm();
-  // Compute this only once, it's expensive.
-  unsigned UserOffset = getUserOffset(U);
-
-  // See if the current entry is within range, or there is a clone of it
-  // in range.
-  int result = findInRangeCPEntry(U, UserOffset);
-  if (result==1) return false;
-  else if (result==2) return true;
-
-
-  // Look for water where we can place this CPE.
-  MachineBasicBlock *NewIsland = MF->CreateMachineBasicBlock();
-  MachineBasicBlock *NewMBB;
-  water_iterator IP;
-  if (findAvailableWater(U, UserOffset, IP)) {
-    DEBUG(dbgs() << "Found water in range\n");
-    MachineBasicBlock *WaterBB = *IP;
-
-    // If the original WaterList entry was "new water" on this iteration,
-    // propagate that to the new island.  This is just keeping NewWaterList
-    // updated to match the WaterList, which will be updated below.
-    if (NewWaterList.erase(WaterBB))
-      NewWaterList.insert(NewIsland);
-
-    // The new CPE goes before the following block (NewMBB).
-    NewMBB = llvm::next(MachineFunction::iterator(WaterBB));
-
-  } else {
-    // No water found.
-    // we first see if a longer form of the instrucion could have reached the constant.
-    // in that case we won't bother to split
-#ifdef IN_PROGRESS
-    result = findLongFormInRangeCPEntry(U, UserOffset);
-#endif
-    DEBUG(dbgs() << "No water found\n");
-    createNewWater(CPUserIndex, UserOffset, NewMBB);
-
-    // splitBlockBeforeInstr adds to WaterList, which is important when it is
-    // called while handling branches so that the water will be seen on the
-    // next iteration for constant pools, but in this context, we don't want
-    // it.  Check for this so it will be removed from the WaterList.
-    // Also remove any entry from NewWaterList.
-    MachineBasicBlock *WaterBB = prior(MachineFunction::iterator(NewMBB));
-    IP = std::find(WaterList.begin(), WaterList.end(), WaterBB);
-    if (IP != WaterList.end())
-      NewWaterList.erase(WaterBB);
-
-    // We are adding new water.  Update NewWaterList.
-    NewWaterList.insert(NewIsland);
-  }
-
-  // Remove the original WaterList entry; we want subsequent insertions in
-  // this vicinity to go after the one we're about to insert.  This
-  // considerably reduces the number of times we have to move the same CPE
-  // more than once and is also important to ensure the algorithm terminates.
-  if (IP != WaterList.end())
-    WaterList.erase(IP);
-
-  // Okay, we know we can put an island before NewMBB now, do it!
-  MF->insert(NewMBB, NewIsland);
-
-  // Update internal data structures to account for the newly inserted MBB.
-  updateForInsertedWaterBlock(NewIsland);
-
-  // Decrement the old entry, and remove it if refcount becomes 0.
-  decrementCPEReferenceCount(CPI, CPEMI);
-
-  // Now that we have an island to add the CPE to, clone the original CPE and
-  // add it to the island.
-  U.HighWaterMark = NewIsland;
-  U.CPEMI = BuildMI(NewIsland, DebugLoc(), TII->get(Mips::CONSTPOOL_ENTRY))
-                .addImm(ID).addConstantPoolIndex(CPI).addImm(Size);
-  CPEntries[CPI].push_back(CPEntry(U.CPEMI, ID, 1));
-  ++NumCPEs;
-
-  // Mark the basic block as aligned as required by the const-pool entry.
-  NewIsland->setAlignment(getCPELogAlign(U.CPEMI));
-
-  // Increase the size of the island block to account for the new entry.
-  BBInfo[NewIsland->getNumber()].Size += Size;
-  adjustBBOffsetsAfter(llvm::prior(MachineFunction::iterator(NewIsland)));
-
-  // No existing clone of this CPE is within range.
-  // We will be generating a new clone.  Get a UID for it.
-  unsigned ID = createPICLabelUId();
-
-  // Finally, change the CPI in the instruction operand to be ID.
-  for (unsigned i = 0, e = UserMI->getNumOperands(); i != e; ++i)
-    if (UserMI->getOperand(i).isCPI()) {
-      UserMI->getOperand(i).setIndex(ID);
-      break;
-    }
-
-  DEBUG(dbgs() << "  Moved CPE to #" << ID << " CPI=" << CPI
-        << format(" offset=%#x\n", BBInfo[NewIsland->getNumber()].Offset));
-
-  return true;
-}
-
-/// removeDeadCPEMI - Remove a dead constant pool entry instruction. Update
-/// sizes and offsets of impacted basic blocks.
-void MipsConstantIslands::removeDeadCPEMI(MachineInstr *CPEMI) {
-  MachineBasicBlock *CPEBB = CPEMI->getParent();
-  unsigned Size = CPEMI->getOperand(2).getImm();
-  CPEMI->eraseFromParent();
-  BBInfo[CPEBB->getNumber()].Size -= Size;
-  // All succeeding offsets have the current size value added in, fix this.
-  if (CPEBB->empty()) {
-    BBInfo[CPEBB->getNumber()].Size = 0;
-
-    // This block no longer needs to be aligned.
-    CPEBB->setAlignment(0);
-  } else
-    // Entries are sorted by descending alignment, so realign from the front.
-    CPEBB->setAlignment(getCPELogAlign(CPEBB->begin()));
-
-  adjustBBOffsetsAfter(CPEBB);
-  // An island has only one predecessor BB and one successor BB. Check if
-  // this BB's predecessor jumps directly to this BB's successor. This
-  // shouldn't happen currently.
-  assert(!BBIsJumpedOver(CPEBB) && "How did this happen?");
-  // FIXME: remove the empty blocks after all the work is done?
-}
-
-/// removeUnusedCPEntries - Remove constant pool entries whose refcounts
-/// are zero.
-bool MipsConstantIslands::removeUnusedCPEntries() {
-  unsigned MadeChange = false;
-  for (unsigned i = 0, e = CPEntries.size(); i != e; ++i) {
-      std::vector<CPEntry> &CPEs = CPEntries[i];
-      for (unsigned j = 0, ee = CPEs.size(); j != ee; ++j) {
-        if (CPEs[j].RefCount == 0 && CPEs[j].CPEMI) {
-          removeDeadCPEMI(CPEs[j].CPEMI);
-          CPEs[j].CPEMI = NULL;
-          MadeChange = true;
-        }
-      }
-  }
-  return MadeChange;
-}
-
-/// isBBInRange - Returns true if the distance between specific MI and
-/// specific BB can fit in MI's displacement field.
-bool MipsConstantIslands::isBBInRange(MachineInstr *MI,MachineBasicBlock *DestBB,
-                                     unsigned MaxDisp) {
-#ifdef IN_PROGRESS
-  unsigned PCAdj      = isThumb ? 4 : 8;
-#else
-  unsigned PCAdj = 4;
-#endif
-  unsigned BrOffset   = getOffsetOf(MI) + PCAdj;
-  unsigned DestOffset = BBInfo[DestBB->getNumber()].Offset;
-
-  DEBUG(dbgs() << "Branch of destination BB#" << DestBB->getNumber()
-               << " from BB#" << MI->getParent()->getNumber()
-               << " max delta=" << MaxDisp
-               << " from " << getOffsetOf(MI) << " to " << DestOffset
-               << " offset " << int(DestOffset-BrOffset) << "\t" << *MI);
-
-  if (BrOffset <= DestOffset) {
-    // Branch before the Dest.
-    if (DestOffset-BrOffset <= MaxDisp)
-      return true;
-  } else {
-    if (BrOffset-DestOffset <= MaxDisp)
-      return true;
-  }
-  return false;
-}
-
-/// fixupImmediateBr - Fix up an immediate branch whose destination is too far
-/// away to fit in its displacement field.
-bool MipsConstantIslands::fixupImmediateBr(ImmBranch &Br) {
-  MachineInstr *MI = Br.MI;
-  MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
-
-  // Check to see if the DestBB is already in-range.
-  if (isBBInRange(MI, DestBB, Br.MaxDisp))
-    return false;
-
-  if (!Br.isCond)
-    return fixupUnconditionalBr(Br);
-  return fixupConditionalBr(Br);
-}
-
-/// fixupUnconditionalBr - Fix up an unconditional branch whose destination is
-/// too far away to fit in its displacement field. If the LR register has been
-/// spilled in the epilogue, then we can use BL to implement a far jump.
-/// Otherwise, add an intermediate branch instruction to a branch.
-bool
-MipsConstantIslands::fixupUnconditionalBr(ImmBranch &Br) {
-  MachineInstr *MI = Br.MI;
-  MachineBasicBlock *MBB = MI->getParent();
-#ifdef IN_PROGRESS
-  if (!isThumb1)
-    llvm_unreachable("fixupUnconditionalBr is Thumb1 only!");
-#endif
-  // Use BL to implement far jump.
-  Br.MaxDisp = (1 << 21) * 2;
-#ifdef IN_PROGRESS
-  MI->setDesc(TII->get(ARM::tBfar));
-#endif
-  BBInfo[MBB->getNumber()].Size += 2;
-  adjustBBOffsetsAfter(MBB);
-  HasFarJump = true;
-  ++NumUBrFixed;
-
-  DEBUG(dbgs() << "  Changed B to long jump " << *MI);
-
-  return true;
-}
-
-/// fixupConditionalBr - Fix up a conditional branch whose destination is too
-/// far away to fit in its displacement field. It is converted to an inverse
-/// conditional branch + an unconditional branch to the destination.
-bool
-MipsConstantIslands::fixupConditionalBr(ImmBranch &Br) {
-#ifdef IN_PROGRESS
-  MachineInstr *MI = Br.MI;
-  MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
-
-  // Add an unconditional branch to the destination and invert the branch
-  // condition to jump over it:
-  // blt L1
-  // =>
-  // bge L2
-  // b   L1
-  // L2:
-  ARMCC::CondCodes CC = (ARMCC::CondCodes)MI->getOperand(1).getImm();
-  CC = ARMCC::getOppositeCondition(CC);
-  unsigned CCReg = MI->getOperand(2).getReg();
-
-  // If the branch is at the end of its MBB and that has a fall-through block,
-  // direct the updated conditional branch to the fall-through block. Otherwise,
-  // split the MBB before the next instruction.
-  MachineBasicBlock *MBB = MI->getParent();
-  MachineInstr *BMI = &MBB->back();
-  bool NeedSplit = (BMI != MI) || !BBHasFallthrough(MBB);
-
-  ++NumCBrFixed;
-  if (BMI != MI) {
-    if (llvm::next(MachineBasicBlock::iterator(MI)) == prior(MBB->end()) &&
-        BMI->getOpcode() == Br.UncondBr) {
-      // Last MI in the BB is an unconditional branch. Can we simply invert the
-      // condition and swap destinations:
-      // beq L1
-      // b   L2
-      // =>
-      // bne L2
-      // b   L1
-      MachineBasicBlock *NewDest = BMI->getOperand(0).getMBB();
-      if (isBBInRange(MI, NewDest, Br.MaxDisp)) {
-        DEBUG(dbgs() << "  Invert Bcc condition and swap its destination with "
-                     << *BMI);
-        BMI->getOperand(0).setMBB(DestBB);
-        MI->getOperand(0).setMBB(NewDest);
-        MI->getOperand(1).setImm(CC);
-        return true;
-      }
-    }
-  }
-
-  if (NeedSplit) {
-    splitBlockBeforeInstr(MI);
-    // No need for the branch to the next block. We're adding an unconditional
-    // branch to the destination.
-    int delta = TII->GetInstSizeInBytes(&MBB->back());
-    BBInfo[MBB->getNumber()].Size -= delta;
-    MBB->back().eraseFromParent();
-    // BBInfo[SplitBB].Offset is wrong temporarily, fixed below
-  }
-  MachineBasicBlock *NextBB = llvm::next(MachineFunction::iterator(MBB));
-
-  DEBUG(dbgs() << "  Insert B to BB#" << DestBB->getNumber()
-               << " also invert condition and change dest. to BB#"
-               << NextBB->getNumber() << "\n");
-
-  // Insert a new conditional branch and a new unconditional branch.
-  // Also update the ImmBranch as well as adding a new entry for the new branch.
-  BuildMI(MBB, DebugLoc(), TII->get(MI->getOpcode()))
-    .addMBB(NextBB).addImm(CC).addReg(CCReg);
-  Br.MI = &MBB->back();
-  BBInfo[MBB->getNumber()].Size += TII->GetInstSizeInBytes(&MBB->back());
-  if (isThumb)
-    BuildMI(MBB, DebugLoc(), TII->get(Br.UncondBr)).addMBB(DestBB)
-            .addImm(ARMCC::AL).addReg(0);
-  else
-    BuildMI(MBB, DebugLoc(), TII->get(Br.UncondBr)).addMBB(DestBB);
-  BBInfo[MBB->getNumber()].Size += TII->GetInstSizeInBytes(&MBB->back());
-  unsigned MaxDisp = getUnconditionalBrDisp(Br.UncondBr);
-  ImmBranches.push_back(ImmBranch(&MBB->back(), MaxDisp, false, Br.UncondBr));
-
-  // Remove the old conditional branch.  It may or may not still be in MBB.
-  BBInfo[MI->getParent()->getNumber()].Size -= TII->GetInstSizeInBytes(MI);
-  MI->eraseFromParent();
-  adjustBBOffsetsAfter(MBB);
-#endif
-  return true;
-}
-
 
 void MipsConstantIslands::prescanForConstants() {
   unsigned int J;
-  PrescannedForConstants = true;
   for (MachineFunction::iterator B =
          MF->begin(), E = MF->end(); B != E; ++B) {
     for (MachineBasicBlock::instr_iterator I =
@@ -1715,11 +238,10 @@ void MipsConstantIslands::prescanForConstants() {
             unsigned index = MCP->getConstantPoolIndex(C, 4);
             I->getOperand(2).ChangeToImmediate(index);
             DEBUG(dbgs() << "constant island constant " << *I << "\n");
-            I->setDesc(TII->get(Mips::LwRxPcTcp16));
+            I->setDesc(TII->get(Mips::LwRxPcTcpX16));
             I->RemoveOperand(1);
             I->RemoveOperand(1);
             I->addOperand(MachineOperand::CreateCPI(index, 0));
-            I->addOperand(MachineOperand::CreateImm(4));
           }
           break;
         }
@@ -1729,4 +251,3 @@ void MipsConstantIslands::prescanForConstants() {
     }
   }
 }
-