+/// 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;
+}
+