Beispiel #1
0
/// Return the corresponding compact (no delay slot) form of a branch.
unsigned MipsInstrInfo::getEquivalentCompactForm(
    const MachineBasicBlock::iterator I) const {
  unsigned Opcode = I->getOpcode();
  bool canUseShortMicroMipsCTI = false;

  if (Subtarget.inMicroMipsMode()) {
    switch (Opcode) {
    case Mips::BNE:
    case Mips::BNE_MM:
    case Mips::BEQ:
    case Mips::BEQ_MM:
    // microMIPS has NE,EQ branches that do not have delay slots provided one
    // of the operands is zero.
      if (I->getOperand(1).getReg() == Subtarget.getABI().GetZeroReg())
        canUseShortMicroMipsCTI = true;
      break;
    // For microMIPS the PseudoReturn and PseudoIndirectBranch are always
    // expanded to JR_MM, so they can be replaced with JRC16_MM.
    case Mips::JR:
    case Mips::PseudoReturn:
    case Mips::PseudoIndirectBranch:
      canUseShortMicroMipsCTI = true;
      break;
    }
  }

  // MIPSR6 forbids both operands being the zero register.
  if (Subtarget.hasMips32r6() && (I->getNumOperands() > 1) &&
      (I->getOperand(0).isReg() &&
       (I->getOperand(0).getReg() == Mips::ZERO ||
        I->getOperand(0).getReg() == Mips::ZERO_64)) &&
      (I->getOperand(1).isReg() &&
       (I->getOperand(1).getReg() == Mips::ZERO ||
        I->getOperand(1).getReg() == Mips::ZERO_64)))
    return 0;

  if (Subtarget.hasMips32r6() || canUseShortMicroMipsCTI) {
    switch (Opcode) {
    case Mips::B:
      return Mips::BC;
    case Mips::BAL:
      return Mips::BALC;
    case Mips::BEQ:
    case Mips::BEQ_MM:
      if (canUseShortMicroMipsCTI)
        return Mips::BEQZC_MM;
      else if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
        return 0;
      return Mips::BEQC;
    case Mips::BNE:
    case Mips::BNE_MM:
      if (canUseShortMicroMipsCTI)
        return Mips::BNEZC_MM;
      else if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
        return 0;
      return Mips::BNEC;
    case Mips::BGE:
      if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
        return 0;
      return Mips::BGEC;
    case Mips::BGEU:
      if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
        return 0;
      return Mips::BGEUC;
    case Mips::BGEZ:
      return Mips::BGEZC;
    case Mips::BGTZ:
      return Mips::BGTZC;
    case Mips::BLEZ:
      return Mips::BLEZC;
    case Mips::BLT:
      if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
        return 0;
      return Mips::BLTC;
    case Mips::BLTU:
      if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
        return 0;
      return Mips::BLTUC;
    case Mips::BLTZ:
      return Mips::BLTZC;
    case Mips::BEQ64:
      if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
        return 0;
      return Mips::BEQC64;
    case Mips::BNE64:
      if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
        return 0;
      return Mips::BNEC64;
    case Mips::BGTZ64:
      return Mips::BGTZC64;
    case Mips::BGEZ64:
      return Mips::BGEZC64;
    case Mips::BLTZ64:
      return Mips::BLTZC64;
    case Mips::BLEZ64:
      return Mips::BLEZC64;
    // For MIPSR6, the instruction 'jic' can be used for these cases. Some
    // tools will accept 'jrc reg' as an alias for 'jic 0, $reg'.
    case Mips::JR:
    case Mips::PseudoIndirectBranchR6:
    case Mips::PseudoReturn:
    case Mips::TAILCALLR6REG:
      if (canUseShortMicroMipsCTI)
        return Mips::JRC16_MM;
      return Mips::JIC;
    case Mips::JALRPseudo:
      return Mips::JIALC;
    case Mips::JR64:
    case Mips::PseudoIndirectBranch64R6:
    case Mips::PseudoReturn64:
    case Mips::TAILCALL64R6REG:
      return Mips::JIC64;
    case Mips::JALR64Pseudo:
      return Mips::JIALC64;
    default:
      return 0;
    }
  }

  return 0;
}
bool MipsSEInstrInfo::expandPostRAPseudo(MachineBasicBlock::iterator MI) const {
  MachineBasicBlock &MBB = *MI->getParent();
  bool isMicroMips = Subtarget.inMicroMipsMode();
  unsigned Opc;

  switch(MI->getDesc().getOpcode()) {
  default:
    return false;
  case Mips::RetRA:
    expandRetRA(MBB, MI);
    break;
  case Mips::PseudoMFHI:
    Opc = isMicroMips ? Mips::MFHI16_MM : Mips::MFHI;
    expandPseudoMFHiLo(MBB, MI, Opc);
    break;
  case Mips::PseudoMFLO:
    Opc = isMicroMips ? Mips::MFLO16_MM : Mips::MFLO;
    expandPseudoMFHiLo(MBB, MI, Opc);
    break;
  case Mips::PseudoMFHI64:
    expandPseudoMFHiLo(MBB, MI, Mips::MFHI64);
    break;
  case Mips::PseudoMFLO64:
    expandPseudoMFHiLo(MBB, MI, Mips::MFLO64);
    break;
  case Mips::PseudoMTLOHI:
    expandPseudoMTLoHi(MBB, MI, Mips::MTLO, Mips::MTHI, false);
    break;
  case Mips::PseudoMTLOHI64:
    expandPseudoMTLoHi(MBB, MI, Mips::MTLO64, Mips::MTHI64, false);
    break;
  case Mips::PseudoMTLOHI_DSP:
    expandPseudoMTLoHi(MBB, MI, Mips::MTLO_DSP, Mips::MTHI_DSP, true);
    break;
  case Mips::PseudoCVT_S_W:
    expandCvtFPInt(MBB, MI, Mips::CVT_S_W, Mips::MTC1, false);
    break;
  case Mips::PseudoCVT_D32_W:
    expandCvtFPInt(MBB, MI, Mips::CVT_D32_W, Mips::MTC1, false);
    break;
  case Mips::PseudoCVT_S_L:
    expandCvtFPInt(MBB, MI, Mips::CVT_S_L, Mips::DMTC1, true);
    break;
  case Mips::PseudoCVT_D64_W:
    expandCvtFPInt(MBB, MI, Mips::CVT_D64_W, Mips::MTC1, true);
    break;
  case Mips::PseudoCVT_D64_L:
    expandCvtFPInt(MBB, MI, Mips::CVT_D64_L, Mips::DMTC1, true);
    break;
  case Mips::BuildPairF64:
    expandBuildPairF64(MBB, MI, false);
    break;
  case Mips::BuildPairF64_64:
    expandBuildPairF64(MBB, MI, true);
    break;
  case Mips::ExtractElementF64:
    expandExtractElementF64(MBB, MI, false);
    break;
  case Mips::ExtractElementF64_64:
    expandExtractElementF64(MBB, MI, true);
    break;
  case Mips::MIPSeh_return32:
  case Mips::MIPSeh_return64:
    expandEhReturn(MBB, MI);
    break;
  }

  MBB.erase(MI);
  return true;
}
Beispiel #3
0
bool
AArch64InstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB,
                                MachineBasicBlock *&FBB,
                                SmallVectorImpl<MachineOperand> &Cond,
                                bool AllowModify) const {
  // If the block has no terminators, it just falls into the block after it.
  MachineBasicBlock::iterator I = MBB.end();
  if (I == MBB.begin())
    return false;
  --I;
  while (I->isDebugValue()) {
    if (I == MBB.begin())
      return false;
    --I;
  }
  if (!isUnpredicatedTerminator(I))
    return false;

  // Get the last instruction in the block.
  MachineInstr *LastInst = I;

  // If there is only one terminator instruction, process it.
  unsigned LastOpc = LastInst->getOpcode();
  if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
    if (LastOpc == AArch64::Bimm) {
      TBB = LastInst->getOperand(0).getMBB();
      return false;
    }
    if (isCondBranch(LastOpc)) {
      classifyCondBranch(LastInst, TBB, Cond);
      return false;
    }
    return true;  // Can't handle indirect branch.
  }

  // Get the instruction before it if it is a terminator.
  MachineInstr *SecondLastInst = I;
  unsigned SecondLastOpc = SecondLastInst->getOpcode();

  // If AllowModify is true and the block ends with two or more unconditional
  // branches, delete all but the first unconditional branch.
  if (AllowModify && LastOpc == AArch64::Bimm) {
    while (SecondLastOpc == AArch64::Bimm) {
      LastInst->eraseFromParent();
      LastInst = SecondLastInst;
      LastOpc = LastInst->getOpcode();
      if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
        // Return now the only terminator is an unconditional branch.
        TBB = LastInst->getOperand(0).getMBB();
        return false;
      } else {
        SecondLastInst = I;
        SecondLastOpc = SecondLastInst->getOpcode();
      }
    }
  }

  // If there are three terminators, we don't know what sort of block this is.
  if (SecondLastInst && I != MBB.begin() && isUnpredicatedTerminator(--I))
    return true;

  // If the block ends with a B and a Bcc, handle it.
  if (LastOpc == AArch64::Bimm) {
    if (SecondLastOpc == AArch64::Bcc) {
      TBB =  SecondLastInst->getOperand(1).getMBB();
      Cond.push_back(MachineOperand::CreateImm(AArch64::Bcc));
      Cond.push_back(SecondLastInst->getOperand(0));
      FBB = LastInst->getOperand(0).getMBB();
      return false;
    } else if (isCondBranch(SecondLastOpc)) {
      classifyCondBranch(SecondLastInst, TBB, Cond);
      FBB = LastInst->getOperand(0).getMBB();
      return false;
    }
  }

  // If the block ends with two unconditional branches, handle it.  The second
  // one is not executed, so remove it.
  if (SecondLastOpc == AArch64::Bimm && LastOpc == AArch64::Bimm) {
    TBB = SecondLastInst->getOperand(0).getMBB();
    I = LastInst;
    if (AllowModify)
      I->eraseFromParent();
    return false;
  }

  // Otherwise, can't handle this.
  return true;
}
bool SparcInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,
                                   MachineBasicBlock *&TBB,
                                   MachineBasicBlock *&FBB,
                                   SmallVectorImpl<MachineOperand> &Cond,
                                   bool AllowModify) const
{

  MachineBasicBlock::iterator I = MBB.end();
  MachineBasicBlock::iterator UnCondBrIter = MBB.end();
  while (I != MBB.begin()) {
    --I;

    if (I->isDebugValue())
      continue;

    //When we see a non-terminator, we are done
    if (!isUnpredicatedTerminator(I))
      break;

    //Terminator is not a branch
    if (!I->getDesc().isBranch())
      return true;

    //Handle Unconditional branches
    if (I->getOpcode() == SP::BA) {
      UnCondBrIter = I;

      if (!AllowModify) {
        TBB = I->getOperand(0).getMBB();
        continue;
      }

      while (llvm::next(I) != MBB.end())
        llvm::next(I)->eraseFromParent();

      Cond.clear();
      FBB = 0;

      if (MBB.isLayoutSuccessor(I->getOperand(0).getMBB())) {
        TBB = 0;
        I->eraseFromParent();
        I = MBB.end();
        UnCondBrIter = MBB.end();
        continue;
      }

      TBB = I->getOperand(0).getMBB();
      continue;
    }

    unsigned Opcode = I->getOpcode();
    if (Opcode != SP::BCOND && Opcode != SP::FBCOND)
      return true; //Unknown Opcode

    SPCC::CondCodes BranchCode = (SPCC::CondCodes)I->getOperand(1).getImm();

    if (Cond.empty()) {
      MachineBasicBlock *TargetBB = I->getOperand(0).getMBB();
      if (AllowModify && UnCondBrIter != MBB.end() &&
          MBB.isLayoutSuccessor(TargetBB)) {

        //Transform the code
        //
        //    brCC L1
        //    ba L2
        // L1:
        //    ..
        // L2:
        //
        // into
        //
        //   brnCC L2
        // L1:
        //   ...
        // L2:
        //
        BranchCode = GetOppositeBranchCondition(BranchCode);
        MachineBasicBlock::iterator OldInst = I;
        BuildMI(MBB, UnCondBrIter, MBB.findDebugLoc(I), get(Opcode))
          .addMBB(UnCondBrIter->getOperand(0).getMBB()).addImm(BranchCode);
        BuildMI(MBB, UnCondBrIter, MBB.findDebugLoc(I), get(SP::BA))
          .addMBB(TargetBB);
        MBB.addSuccessor(TargetBB);
        OldInst->eraseFromParent();
        UnCondBrIter->eraseFromParent();

        UnCondBrIter = MBB.end();
        I = MBB.end();
        continue;
      }
      FBB = TBB;
      TBB = I->getOperand(0).getMBB();
      Cond.push_back(MachineOperand::CreateImm(BranchCode));
      continue;
    }
    //FIXME: Handle subsequent conditional branches
    //For now, we can't handle multiple conditional branches
    return true;
  }
  return false;
}
Beispiel #5
0
unsigned LembergInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
	
  MachineBasicBlock::iterator I = MBB.end();
  if (I == MBB.begin()) return 0;
  --I;
  if (I->getOpcode() != Lemberg::JUMP &&
	  I->getOpcode() != Lemberg::JUMPtrue &&
	  I->getOpcode() != Lemberg::JUMPfalse &&
	  I->getOpcode() != Lemberg::JUMPpred &&
	  I->getOpcode() != Lemberg::JUMPeqz &&
	  I->getOpcode() != Lemberg::JUMPnez &&
	  I->getOpcode() != Lemberg::JUMPltz &&
	  I->getOpcode() != Lemberg::JUMPgez &&
	  I->getOpcode() != Lemberg::JUMPgtz &&
	  I->getOpcode() != Lemberg::JUMPlez)
    return 0;

  // Remove the branch.
  I->eraseFromParent();

  I = MBB.end();

  if (I == MBB.begin()) return 1;
  --I;
  if (I->getOpcode() != Lemberg::JUMPtrue &&
	  I->getOpcode() != Lemberg::JUMPfalse &&
	  I->getOpcode() != Lemberg::JUMPpred &&
	  I->getOpcode() != Lemberg::JUMPeqz &&
	  I->getOpcode() != Lemberg::JUMPnez &&
	  I->getOpcode() != Lemberg::JUMPltz &&
	  I->getOpcode() != Lemberg::JUMPgez &&
	  I->getOpcode() != Lemberg::JUMPgtz &&
	  I->getOpcode() != Lemberg::JUMPlez)
    return 1;

  // Remove the branch.
  I->eraseFromParent();
  return 2;
}
Beispiel #6
0
MachineBasicBlock::iterator
Filler::findDelayInstr(MachineBasicBlock &MBB,
                       MachineBasicBlock::iterator slot)
{
  SmallSet<unsigned, 32> RegDefs;
  SmallSet<unsigned, 32> RegUses;
  bool sawLoad = false;
  bool sawStore = false;

  if (slot == MBB.begin())
    return MBB.end();

  if (slot->getOpcode() == SP::RET || slot->getOpcode() == SP::TLS_CALL)
    return MBB.end();

  if (slot->getOpcode() == SP::RETL) {
    MachineBasicBlock::iterator J = slot;
    --J;

    if (J->getOpcode() == SP::RESTORErr
        || J->getOpcode() == SP::RESTOREri) {
      // change retl to ret.
      slot->setDesc(TM.getInstrInfo()->get(SP::RET));
      return J;
    }
  }

  // Call's delay filler can def some of call's uses.
  if (slot->isCall())
    insertCallDefsUses(slot, RegDefs, RegUses);
  else
    insertDefsUses(slot, RegDefs, RegUses);

  bool done = false;

  MachineBasicBlock::iterator I = slot;

  while (!done) {
    done = (I == MBB.begin());

    if (!done)
      --I;

    // skip debug value
    if (I->isDebugValue())
      continue;

    if (I->hasUnmodeledSideEffects() || I->isInlineAsm() || I->isPosition() ||
        I->hasDelaySlot() || I->isBundledWithSucc())
      break;

    if (delayHasHazard(I, sawLoad, sawStore, RegDefs, RegUses)) {
      insertDefsUses(I, RegDefs, RegUses);
      continue;
    }

    return I;
  }
  return MBB.end();
}
bool PatmosDelaySlotKiller::killDelaySlots(MachineBasicBlock &MBB) {
  bool Changed = false;

  DEBUG( dbgs() << "Killing slots in BB#" << MBB.getNumber()
                << " (" << MBB.getFullName() << ")\n" );

  // consider the basic block from top to bottom
  for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I) {
    // Control-flow instructions ("proper" delay slots)
    if (I->hasDelaySlot()) {
      assert( ( I->isCall() || I->isReturn() || I->isBranch() )
              && "Unexpected instruction with delay slot.");

      MachineBasicBlock::instr_iterator MI = *I;
      if (I->isBundle()) { ++MI; }

      unsigned Opcode = MI->getOpcode();

      if (Opcode == Patmos::BR ||
          Opcode == Patmos::BRu ||
          Opcode == Patmos::BRR ||
          Opcode == Patmos::BRRu ||
          Opcode == Patmos::BRT ||
          Opcode == Patmos::BRTu ||
          Opcode == Patmos::BRCF ||
          Opcode == Patmos::BRCFu ||
          Opcode == Patmos::BRCFR ||
          Opcode == Patmos::BRCFRu ||
          Opcode == Patmos::BRCFT ||
          Opcode == Patmos::BRCFTu ||
          Opcode == Patmos::CALL ||
          Opcode == Patmos::CALLR ||
          Opcode == Patmos::RET ||
          Opcode == Patmos::XRET) {

        bool onlyNops = true;
        unsigned maxCount = TM.getSubtargetImpl()->getDelaySlotCycles(&*I);
        unsigned count = 0;
        for (MachineBasicBlock::iterator K = llvm::next(I), E = MBB.end();
             K != E && count < maxCount; ++K, ++count) {
          if (K->getOpcode() != Patmos::NOP) {
            onlyNops = false;
          }
        }
        if (onlyNops) {
          unsigned NewOpcode = 0;
          switch(Opcode) {
          case Patmos::BR:     NewOpcode = Patmos::BRND; break;
          case Patmos::BRu:    NewOpcode = Patmos::BRNDu; break;
          case Patmos::BRR:    NewOpcode = Patmos::BRRND; break;
          case Patmos::BRRu:   NewOpcode = Patmos::BRRNDu; break;
          case Patmos::BRT:    NewOpcode = Patmos::BRTND; break;
          case Patmos::BRTu:   NewOpcode = Patmos::BRTNDu; break;
          case Patmos::BRCF:   NewOpcode = Patmos::BRCFND; break;
          case Patmos::BRCFu:  NewOpcode = Patmos::BRCFNDu; break;
          case Patmos::BRCFR:  NewOpcode = Patmos::BRCFRND; break;
          case Patmos::BRCFRu: NewOpcode = Patmos::BRCFRNDu; break;
          case Patmos::BRCFT:  NewOpcode = Patmos::BRCFTND; break;
          case Patmos::BRCFTu: NewOpcode = Patmos::BRCFTNDu; break;
          case Patmos::CALL:   NewOpcode = Patmos::CALLND; break;
          case Patmos::CALLR:  NewOpcode = Patmos::CALLRND; break;
          case Patmos::RET:    NewOpcode = Patmos::RETND; break;
          case Patmos::XRET:   NewOpcode = Patmos::XRETND; break;
          }
          const MCInstrDesc &nonDelayed = TII->get(NewOpcode);
          MI->setDesc(nonDelayed);

          unsigned killCount = 0;
          MachineBasicBlock::iterator K = llvm::next(I);
          for (MachineBasicBlock::iterator E = MBB.end();
               K != E && killCount < count; ++K, ++killCount) {
            KilledSlots++;
          }
          MBB.erase(llvm::next(I), K);
        }
      }
      Changed = true; // pass result
    }
  }
  return Changed;
}
Beispiel #8
0
/// runOnMachineFunction - Reduce two-address instructions to two operands.
///
bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
  DEBUG(errs() << "Machine Function\n");
  const TargetMachine &TM = MF.getTarget();
  MRI = &MF.getRegInfo();
  TII = TM.getInstrInfo();
  TRI = TM.getRegisterInfo();
  LV = getAnalysisIfAvailable<LiveVariables>();
  AA = &getAnalysis<AliasAnalysis>();

  bool MadeChange = false;

  DEBUG(errs() << "********** REWRITING TWO-ADDR INSTRS **********\n");
  DEBUG(errs() << "********** Function: " 
        << MF.getFunction()->getName() << '\n');

  // ReMatRegs - Keep track of the registers whose def's are remat'ed.
  BitVector ReMatRegs;
  ReMatRegs.resize(MRI->getLastVirtReg()+1);

  typedef DenseMap<unsigned, SmallVector<std::pair<unsigned, unsigned>, 4> >
    TiedOperandMap;
  TiedOperandMap TiedOperands(4);

  SmallPtrSet<MachineInstr*, 8> Processed;
  for (MachineFunction::iterator mbbi = MF.begin(), mbbe = MF.end();
       mbbi != mbbe; ++mbbi) {
    unsigned Dist = 0;
    DistanceMap.clear();
    SrcRegMap.clear();
    DstRegMap.clear();
    Processed.clear();
    for (MachineBasicBlock::iterator mi = mbbi->begin(), me = mbbi->end();
         mi != me; ) {
      MachineBasicBlock::iterator nmi = next(mi);
      const TargetInstrDesc &TID = mi->getDesc();
      bool FirstTied = true;

      DistanceMap.insert(std::make_pair(mi, ++Dist));

      ProcessCopy(&*mi, &*mbbi, Processed);

      // First scan through all the tied register uses in this instruction
      // and record a list of pairs of tied operands for each register.
      unsigned NumOps = (mi->getOpcode() == TargetInstrInfo::INLINEASM)
        ? mi->getNumOperands() : TID.getNumOperands();
      for (unsigned SrcIdx = 0; SrcIdx < NumOps; ++SrcIdx) {
        unsigned DstIdx = 0;
        if (!mi->isRegTiedToDefOperand(SrcIdx, &DstIdx))
          continue;

        if (FirstTied) {
          FirstTied = false;
          ++NumTwoAddressInstrs;
          DEBUG(errs() << '\t' << *mi);
        }

        assert(mi->getOperand(SrcIdx).isReg() &&
               mi->getOperand(SrcIdx).getReg() &&
               mi->getOperand(SrcIdx).isUse() &&
               "two address instruction invalid");

        unsigned regB = mi->getOperand(SrcIdx).getReg();
        TiedOperandMap::iterator OI = TiedOperands.find(regB);
        if (OI == TiedOperands.end()) {
          SmallVector<std::pair<unsigned, unsigned>, 4> TiedPair;
          OI = TiedOperands.insert(std::make_pair(regB, TiedPair)).first;
        }
        OI->second.push_back(std::make_pair(SrcIdx, DstIdx));
      }

      // Now iterate over the information collected above.
      for (TiedOperandMap::iterator OI = TiedOperands.begin(),
             OE = TiedOperands.end(); OI != OE; ++OI) {
        SmallVector<std::pair<unsigned, unsigned>, 4> &TiedPairs = OI->second;

        // If the instruction has a single pair of tied operands, try some
        // transformations that may either eliminate the tied operands or
        // improve the opportunities for coalescing away the register copy.
        if (TiedOperands.size() == 1 && TiedPairs.size() == 1) {
          unsigned SrcIdx = TiedPairs[0].first;
          unsigned DstIdx = TiedPairs[0].second;

          // If the registers are already equal, nothing needs to be done.
          if (mi->getOperand(SrcIdx).getReg() ==
              mi->getOperand(DstIdx).getReg())
            break; // Done with this instruction.

          if (TryInstructionTransform(mi, nmi, mbbi, SrcIdx, DstIdx, Dist))
            break; // The tied operands have been eliminated.
        }

        bool RemovedKillFlag = false;
        bool AllUsesCopied = true;
        unsigned LastCopiedReg = 0;
        unsigned regB = OI->first;
        for (unsigned tpi = 0, tpe = TiedPairs.size(); tpi != tpe; ++tpi) {
          unsigned SrcIdx = TiedPairs[tpi].first;
          unsigned DstIdx = TiedPairs[tpi].second;
          unsigned regA = mi->getOperand(DstIdx).getReg();
          // Grab regB from the instruction because it may have changed if the
          // instruction was commuted.
          regB = mi->getOperand(SrcIdx).getReg();

          if (regA == regB) {
            // The register is tied to multiple destinations (or else we would
            // not have continued this far), but this use of the register
            // already matches the tied destination.  Leave it.
            AllUsesCopied = false;
            continue;
          }
          LastCopiedReg = regA;

          assert(TargetRegisterInfo::isVirtualRegister(regB) &&
                 "cannot make instruction into two-address form");

#ifndef NDEBUG
          // First, verify that we don't have a use of "a" in the instruction
          // (a = b + a for example) because our transformation will not
          // work. This should never occur because we are in SSA form.
          for (unsigned i = 0; i != mi->getNumOperands(); ++i)
            assert(i == DstIdx ||
                   !mi->getOperand(i).isReg() ||
                   mi->getOperand(i).getReg() != regA);
#endif

          // Emit a copy or rematerialize the definition.
          const TargetRegisterClass *rc = MRI->getRegClass(regB);
          MachineInstr *DefMI = MRI->getVRegDef(regB);
          // If it's safe and profitable, remat the definition instead of
          // copying it.
          if (DefMI &&
              DefMI->getDesc().isAsCheapAsAMove() &&
              DefMI->isSafeToReMat(TII, regB, AA) &&
              isProfitableToReMat(regB, rc, mi, DefMI, mbbi, Dist)){
            DEBUG(errs() << "2addr: REMATTING : " << *DefMI << "\n");
            unsigned regASubIdx = mi->getOperand(DstIdx).getSubReg();
            TII->reMaterialize(*mbbi, mi, regA, regASubIdx, DefMI, TRI);
            ReMatRegs.set(regB);
            ++NumReMats;
          } else {
            bool Emitted = TII->copyRegToReg(*mbbi, mi, regA, regB, rc, rc);
            (void)Emitted;
            assert(Emitted && "Unable to issue a copy instruction!\n");
          }

          MachineBasicBlock::iterator prevMI = prior(mi);
          // Update DistanceMap.
          DistanceMap.insert(std::make_pair(prevMI, Dist));
          DistanceMap[mi] = ++Dist;

          DEBUG(errs() << "\t\tprepend:\t" << *prevMI);

          MachineOperand &MO = mi->getOperand(SrcIdx);
          assert(MO.isReg() && MO.getReg() == regB && MO.isUse() &&
                 "inconsistent operand info for 2-reg pass");
          if (MO.isKill()) {
            MO.setIsKill(false);
            RemovedKillFlag = true;
          }
          MO.setReg(regA);
        }

        if (AllUsesCopied) {
          // Replace other (un-tied) uses of regB with LastCopiedReg.
          for (unsigned i = 0, e = mi->getNumOperands(); i != e; ++i) {
            MachineOperand &MO = mi->getOperand(i);
            if (MO.isReg() && MO.getReg() == regB && MO.isUse()) {
              if (MO.isKill()) {
                MO.setIsKill(false);
                RemovedKillFlag = true;
              }
              MO.setReg(LastCopiedReg);
            }
          }

          // Update live variables for regB.
          if (RemovedKillFlag && LV && LV->getVarInfo(regB).removeKill(mi))
            LV->addVirtualRegisterKilled(regB, prior(mi));

        } else if (RemovedKillFlag) {
          // Some tied uses of regB matched their destination registers, so
          // regB is still used in this instruction, but a kill flag was
          // removed from a different tied use of regB, so now we need to add
          // a kill flag to one of the remaining uses of regB.
          for (unsigned i = 0, e = mi->getNumOperands(); i != e; ++i) {
            MachineOperand &MO = mi->getOperand(i);
            if (MO.isReg() && MO.getReg() == regB && MO.isUse()) {
              MO.setIsKill(true);
              break;
            }
          }
        }
          
        MadeChange = true;

        DEBUG(errs() << "\t\trewrite to:\t" << *mi);
      }

      // Clear TiedOperands here instead of at the top of the loop
      // since most instructions do not have tied operands.
      TiedOperands.clear();
      mi = nmi;
    }
  }

  // Some remat'ed instructions are dead.
  int VReg = ReMatRegs.find_first();
  while (VReg != -1) {
    if (MRI->use_empty(VReg)) {
      MachineInstr *DefMI = MRI->getVRegDef(VReg);
      DefMI->eraseFromParent();
    }
    VReg = ReMatRegs.find_next(VReg);
  }

  return MadeChange;
}
void MipsSEFrameLowering::emitPrologue(MachineFunction &MF) const {
  MachineBasicBlock &MBB   = MF.front();
  MachineFrameInfo *MFI    = MF.getFrameInfo();
  const MipsRegisterInfo *RegInfo =
    static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
  const MipsSEInstrInfo &TII =
    *static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
  MachineBasicBlock::iterator MBBI = MBB.begin();
  DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
  unsigned SP = STI.isABI_N64() ? Mips::SP_64 : Mips::SP;
  unsigned FP = STI.isABI_N64() ? Mips::FP_64 : Mips::FP;
  unsigned ZERO = STI.isABI_N64() ? Mips::ZERO_64 : Mips::ZERO;
  unsigned ADDu = STI.isABI_N64() ? Mips::DADDu : Mips::ADDu;

  // First, compute final stack size.
  uint64_t StackSize = MFI->getStackSize();

  // No need to allocate space on the stack.
  if (StackSize == 0 && !MFI->adjustsStack()) return;

  MachineModuleInfo &MMI = MF.getMMI();
  std::vector<MachineMove> &Moves = MMI.getFrameMoves();
  MachineLocation DstML, SrcML;

  // Adjust stack.
  TII.adjustStackPtr(SP, -StackSize, MBB, MBBI);

  // emit ".cfi_def_cfa_offset StackSize"
  MCSymbol *AdjustSPLabel = MMI.getContext().CreateTempSymbol();
  BuildMI(MBB, MBBI, dl,
          TII.get(TargetOpcode::PROLOG_LABEL)).addSym(AdjustSPLabel);
  DstML = MachineLocation(MachineLocation::VirtualFP);
  SrcML = MachineLocation(MachineLocation::VirtualFP, -StackSize);
  Moves.push_back(MachineMove(AdjustSPLabel, DstML, SrcML));

  const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();

  if (CSI.size()) {
    // Find the instruction past the last instruction that saves a callee-saved
    // register to the stack.
    for (unsigned i = 0; i < CSI.size(); ++i)
      ++MBBI;

    // Iterate over list of callee-saved registers and emit .cfi_offset
    // directives.
    MCSymbol *CSLabel = MMI.getContext().CreateTempSymbol();
    BuildMI(MBB, MBBI, dl,
            TII.get(TargetOpcode::PROLOG_LABEL)).addSym(CSLabel);

    for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
           E = CSI.end(); I != E; ++I) {
      int64_t Offset = MFI->getObjectOffset(I->getFrameIdx());
      unsigned Reg = I->getReg();

      // If Reg is a double precision register, emit two cfa_offsets,
      // one for each of the paired single precision registers.
      if (Mips::AFGR64RegClass.contains(Reg)) {
        MachineLocation DstML0(MachineLocation::VirtualFP, Offset);
        MachineLocation DstML1(MachineLocation::VirtualFP, Offset + 4);
        MachineLocation SrcML0(RegInfo->getSubReg(Reg, Mips::sub_fpeven));
        MachineLocation SrcML1(RegInfo->getSubReg(Reg, Mips::sub_fpodd));

        if (!STI.isLittle())
          std::swap(SrcML0, SrcML1);

        Moves.push_back(MachineMove(CSLabel, DstML0, SrcML0));
        Moves.push_back(MachineMove(CSLabel, DstML1, SrcML1));
      } else {
        // Reg is either in CPURegs or FGR32.
        DstML = MachineLocation(MachineLocation::VirtualFP, Offset);
        SrcML = MachineLocation(Reg);
        Moves.push_back(MachineMove(CSLabel, DstML, SrcML));
      }
    }
  }

  // if framepointer enabled, set it to point to the stack pointer.
  if (hasFP(MF)) {
    // Insert instruction "move $fp, $sp" at this location.
    BuildMI(MBB, MBBI, dl, TII.get(ADDu), FP).addReg(SP).addReg(ZERO);

    // emit ".cfi_def_cfa_register $fp"
    MCSymbol *SetFPLabel = MMI.getContext().CreateTempSymbol();
    BuildMI(MBB, MBBI, dl,
            TII.get(TargetOpcode::PROLOG_LABEL)).addSym(SetFPLabel);
    DstML = MachineLocation(FP);
    SrcML = MachineLocation(MachineLocation::VirtualFP);
    Moves.push_back(MachineMove(SetFPLabel, DstML, SrcML));
  }
}
void MSP430FrameLowering::emitPrologue(MachineFunction &MF) const {
    MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
    MachineFrameInfo *MFI = MF.getFrameInfo();
    MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>();
    const MSP430InstrInfo &TII =
        *static_cast<const MSP430InstrInfo*>(MF.getTarget().getInstrInfo());

    MachineBasicBlock::iterator MBBI = MBB.begin();
    DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();

    // Get the number of bytes to allocate from the FrameInfo.
    uint64_t StackSize = MFI->getStackSize();

    uint64_t NumBytes = 0;
    if (hasFP(MF)) {
        // Calculate required stack adjustment
        uint64_t FrameSize = StackSize - 2;
        NumBytes = FrameSize - MSP430FI->getCalleeSavedFrameSize();

        // Get the offset of the stack slot for the EBP register... which is
        // guaranteed to be the last slot by processFunctionBeforeFrameFinalized.
        // Update the frame offset adjustment.
        MFI->setOffsetAdjustment(-NumBytes);

        // Save FPW into the appropriate stack slot...
        BuildMI(MBB, MBBI, DL, TII.get(MSP430::PUSH16r))
        .addReg(MSP430::FPW, RegState::Kill);

        // Update FPW with the new base value...
        BuildMI(MBB, MBBI, DL, TII.get(MSP430::MOV16rr), MSP430::FPW)
        .addReg(MSP430::SPW);

        // Mark the FramePtr as live-in in every block except the entry.
        for (MachineFunction::iterator I = llvm::next(MF.begin()), E = MF.end();
                I != E; ++I)
            I->addLiveIn(MSP430::FPW);

    } else
        NumBytes = StackSize - MSP430FI->getCalleeSavedFrameSize();

    // Skip the callee-saved push instructions.
    while (MBBI != MBB.end() && (MBBI->getOpcode() == MSP430::PUSH16r))
        ++MBBI;

    if (MBBI != MBB.end())
        DL = MBBI->getDebugLoc();

    if (NumBytes) { // adjust stack pointer: SPW -= numbytes
        // If there is an SUB16ri of SPW immediately before this instruction, merge
        // the two.
        //NumBytes -= mergeSPUpdates(MBB, MBBI, true);
        // If there is an ADD16ri or SUB16ri of SPW immediately after this
        // instruction, merge the two instructions.
        // mergeSPUpdatesDown(MBB, MBBI, &NumBytes);

        if (NumBytes) {
            MachineInstr *MI =
                BuildMI(MBB, MBBI, DL, TII.get(MSP430::SUB16ri), MSP430::SPW)
                .addReg(MSP430::SPW).addImm(NumBytes);
            // The SRW implicit def is dead.
            MI->getOperand(3).setIsDead();
        }
    }
}
Beispiel #11
0
/// TryInstructionTransform - For the case where an instruction has a single
/// pair of tied register operands, attempt some transformations that may
/// either eliminate the tied operands or improve the opportunities for
/// coalescing away the register copy.  Returns true if the tied operands
/// are eliminated altogether.
bool TwoAddressInstructionPass::
TryInstructionTransform(MachineBasicBlock::iterator &mi,
                        MachineBasicBlock::iterator &nmi,
                        MachineFunction::iterator &mbbi,
                        unsigned SrcIdx, unsigned DstIdx, unsigned Dist) {
  const TargetInstrDesc &TID = mi->getDesc();
  unsigned regA = mi->getOperand(DstIdx).getReg();
  unsigned regB = mi->getOperand(SrcIdx).getReg();

  assert(TargetRegisterInfo::isVirtualRegister(regB) &&
         "cannot make instruction into two-address form");

  // If regA is dead and the instruction can be deleted, just delete
  // it so it doesn't clobber regB.
  bool regBKilled = isKilled(*mi, regB, MRI, TII);
  if (!regBKilled && mi->getOperand(DstIdx).isDead() &&
      DeleteUnusedInstr(mi, nmi, mbbi, Dist)) {
    ++NumDeletes;
    return true; // Done with this instruction.
  }

  // Check if it is profitable to commute the operands.
  unsigned SrcOp1, SrcOp2;
  unsigned regC = 0;
  unsigned regCIdx = ~0U;
  bool TryCommute = false;
  bool AggressiveCommute = false;
  if (TID.isCommutable() && mi->getNumOperands() >= 3 &&
      TII->findCommutedOpIndices(mi, SrcOp1, SrcOp2)) {
    if (SrcIdx == SrcOp1)
      regCIdx = SrcOp2;
    else if (SrcIdx == SrcOp2)
      regCIdx = SrcOp1;

    if (regCIdx != ~0U) {
      regC = mi->getOperand(regCIdx).getReg();
      if (!regBKilled && isKilled(*mi, regC, MRI, TII))
        // If C dies but B does not, swap the B and C operands.
        // This makes the live ranges of A and C joinable.
        TryCommute = true;
      else if (isProfitableToCommute(regB, regC, mi, mbbi, Dist)) {
        TryCommute = true;
        AggressiveCommute = true;
      }
    }
  }

  // If it's profitable to commute, try to do so.
  if (TryCommute && CommuteInstruction(mi, mbbi, regB, regC, Dist)) {
    ++NumCommuted;
    if (AggressiveCommute)
      ++NumAggrCommuted;
    return false;
  }

  if (TID.isConvertibleTo3Addr()) {
    // This instruction is potentially convertible to a true
    // three-address instruction.  Check if it is profitable.
    if (!regBKilled || isProfitableToConv3Addr(regA)) {
      // Try to convert it.
      if (ConvertInstTo3Addr(mi, nmi, mbbi, regB, Dist)) {
        ++NumConvertedTo3Addr;
        return true; // Done with this instruction.
      }
    }
  }
  return false;
}
void MSP430FrameLowering::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
                              MachineBasicBlock::iterator I) const {
    const MSP430InstrInfo &TII =
        *static_cast<const MSP430InstrInfo*>(MF.getTarget().getInstrInfo());
    unsigned StackAlign = getStackAlignment();

    if (!hasReservedCallFrame(MF)) {
        // If the stack pointer can be changed after prologue, turn the
        // adjcallstackup instruction into a 'sub SPW, <amt>' and the
        // adjcallstackdown instruction into 'add SPW, <amt>'
        // TODO: consider using push / pop instead of sub + store / add
        MachineInstr *Old = I;
        uint64_t Amount = Old->getOperand(0).getImm();
        if (Amount != 0) {
            // We need to keep the stack aligned properly.  To do this, we round the
            // amount of space needed for the outgoing arguments up to the next
            // alignment boundary.
            Amount = (Amount+StackAlign-1)/StackAlign*StackAlign;

            MachineInstr *New = 0;
            if (Old->getOpcode() == TII.getCallFrameSetupOpcode()) {
                New = BuildMI(MF, Old->getDebugLoc(),
                              TII.get(MSP430::SUB16ri), MSP430::SPW)
                      .addReg(MSP430::SPW).addImm(Amount);
            } else {
                assert(Old->getOpcode() == TII.getCallFrameDestroyOpcode());
                // factor out the amount the callee already popped.
                uint64_t CalleeAmt = Old->getOperand(1).getImm();
                Amount -= CalleeAmt;
                if (Amount)
                    New = BuildMI(MF, Old->getDebugLoc(),
                                  TII.get(MSP430::ADD16ri), MSP430::SPW)
                          .addReg(MSP430::SPW).addImm(Amount);
            }

            if (New) {
                // The SRW implicit def is dead.
                New->getOperand(3).setIsDead();

                // Replace the pseudo instruction with a new instruction...
                MBB.insert(I, New);
            }
        }
    } else if (I->getOpcode() == TII.getCallFrameDestroyOpcode()) {
        // If we are performing frame pointer elimination and if the callee pops
        // something off the stack pointer, add it back.
        if (uint64_t CalleeAmt = I->getOperand(1).getImm()) {
            MachineInstr *Old = I;
            MachineInstr *New =
                BuildMI(MF, Old->getDebugLoc(), TII.get(MSP430::SUB16ri),
                        MSP430::SPW).addReg(MSP430::SPW).addImm(CalleeAmt);
            // The SRW implicit def is dead.
            New->getOperand(3).setIsDead();

            MBB.insert(I, New);
        }
    }

    MBB.erase(I);
}
void MSP430FrameLowering::emitEpilogue(MachineFunction &MF,
                                       MachineBasicBlock &MBB) const {
    const MachineFrameInfo *MFI = MF.getFrameInfo();
    MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>();
    const MSP430InstrInfo &TII =
        *static_cast<const MSP430InstrInfo*>(MF.getTarget().getInstrInfo());

    MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
    unsigned RetOpcode = MBBI->getOpcode();
    DebugLoc DL = MBBI->getDebugLoc();

    switch (RetOpcode) {
    case MSP430::RET:
    case MSP430::RETI:
        break;  // These are ok
    default:
        llvm_unreachable("Can only insert epilog into returning blocks");
    }

    // Get the number of bytes to allocate from the FrameInfo
    uint64_t StackSize = MFI->getStackSize();
    unsigned CSSize = MSP430FI->getCalleeSavedFrameSize();
    uint64_t NumBytes = 0;

    if (hasFP(MF)) {
        // Calculate required stack adjustment
        uint64_t FrameSize = StackSize - 2;
        NumBytes = FrameSize - CSSize;

        // pop FPW.
        BuildMI(MBB, MBBI, DL, TII.get(MSP430::POP16r), MSP430::FPW);
    } else
        NumBytes = StackSize - CSSize;

    // Skip the callee-saved pop instructions.
    while (MBBI != MBB.begin()) {
        MachineBasicBlock::iterator PI = prior(MBBI);
        unsigned Opc = PI->getOpcode();
        if (Opc != MSP430::POP16r && !PI->isTerminator())
            break;
        --MBBI;
    }

    DL = MBBI->getDebugLoc();

    // If there is an ADD16ri or SUB16ri of SPW immediately before this
    // instruction, merge the two instructions.
    //if (NumBytes || MFI->hasVarSizedObjects())
    //  mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);

    if (MFI->hasVarSizedObjects()) {
        BuildMI(MBB, MBBI, DL,
                TII.get(MSP430::MOV16rr), MSP430::SPW).addReg(MSP430::FPW);
        if (CSSize) {
            MachineInstr *MI =
                BuildMI(MBB, MBBI, DL,
                        TII.get(MSP430::SUB16ri), MSP430::SPW)
                .addReg(MSP430::SPW).addImm(CSSize);
            // The SRW implicit def is dead.
            MI->getOperand(3).setIsDead();
        }
    } else {
        // adjust stack pointer back: SPW += numbytes
        if (NumBytes) {
            MachineInstr *MI =
                BuildMI(MBB, MBBI, DL, TII.get(MSP430::ADD16ri), MSP430::SPW)
                .addReg(MSP430::SPW).addImm(NumBytes);
            // The SRW implicit def is dead.
            MI->getOperand(3).setIsDead();
        }
    }
}
Beispiel #14
0
MachineInstrBuilder
MipsInstrInfo::genInstrWithNewOpc(unsigned NewOpc,
                                  MachineBasicBlock::iterator I) const {
  MachineInstrBuilder MIB;

  // Certain branches have two forms: e.g beq $1, $zero, dest vs beqz $1, dest
  // Pick the zero form of the branch for readable assembly and for greater
  // branch distance in non-microMIPS mode.
  // Additional MIPSR6 does not permit the use of register $zero for compact
  // branches.
  // FIXME: Certain atomic sequences on mips64 generate 32bit references to
  // Mips::ZERO, which is incorrect. This test should be updated to use
  // Subtarget.getABI().GetZeroReg() when those atomic sequences and others
  // are fixed.
  int ZeroOperandPosition = -1;
  bool BranchWithZeroOperand = false;
  if (I->isBranch() && !I->isPseudo()) {
    auto TRI = I->getParent()->getParent()->getSubtarget().getRegisterInfo();
    ZeroOperandPosition = I->findRegisterUseOperandIdx(Mips::ZERO, false, TRI);
    BranchWithZeroOperand = ZeroOperandPosition != -1;
  }

  if (BranchWithZeroOperand) {
    switch (NewOpc) {
    case Mips::BEQC:
      NewOpc = Mips::BEQZC;
      break;
    case Mips::BNEC:
      NewOpc = Mips::BNEZC;
      break;
    case Mips::BGEC:
      NewOpc = Mips::BGEZC;
      break;
    case Mips::BLTC:
      NewOpc = Mips::BLTZC;
      break;
    case Mips::BEQC64:
      NewOpc = Mips::BEQZC64;
      break;
    case Mips::BNEC64:
      NewOpc = Mips::BNEZC64;
      break;
    }
  }

  MIB = BuildMI(*I->getParent(), I, I->getDebugLoc(), get(NewOpc));

  // For MIPSR6 JI*C requires an immediate 0 as an operand, JIALC(64) an
  // immediate 0 as an operand and requires the removal of it's implicit-def %ra
  // implicit operand as copying the implicit operations of the instructio we're
  // looking at will give us the correct flags.
  if (NewOpc == Mips::JIC || NewOpc == Mips::JIALC || NewOpc == Mips::JIC64 ||
      NewOpc == Mips::JIALC64) {

    if (NewOpc == Mips::JIALC || NewOpc == Mips::JIALC64)
      MIB->RemoveOperand(0);

    for (unsigned J = 0, E = I->getDesc().getNumOperands(); J < E; ++J) {
      MIB.add(I->getOperand(J));
    }

    MIB.addImm(0);

  } else {
    for (unsigned J = 0, E = I->getDesc().getNumOperands(); J < E; ++J) {
      if (BranchWithZeroOperand && (unsigned)ZeroOperandPosition == J)
        continue;

      MIB.add(I->getOperand(J));
    }
  }

  MIB.copyImplicitOps(*I);

  MIB.setMemRefs(I->memoperands_begin(), I->memoperands_end());
  return MIB;
}
Beispiel #15
0
void MipsSEInstrInfo::
loadRegFromStack(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
                 unsigned DestReg, int FI, const TargetRegisterClass *RC,
                 const TargetRegisterInfo *TRI, int64_t Offset) const {
  DebugLoc DL;
  if (I != MBB.end()) DL = I->getDebugLoc();
  MachineMemOperand *MMO = GetMemOperand(MBB, FI, MachineMemOperand::MOLoad);
  unsigned Opc = 0;

  const Function *Func = MBB.getParent()->getFunction();
  bool ReqIndirectLoad = Func->hasFnAttribute("interrupt") &&
                         (DestReg == Mips::LO0 || DestReg == Mips::LO0_64 ||
                          DestReg == Mips::HI0 || DestReg == Mips::HI0_64);

  if (Mips::GPR32RegClass.hasSubClassEq(RC))
    Opc = Mips::LW;
  else if (Mips::GPR64RegClass.hasSubClassEq(RC))
    Opc = Mips::LD;
  else if (Mips::ACC64RegClass.hasSubClassEq(RC))
    Opc = Mips::LOAD_ACC64;
  else if (Mips::ACC64DSPRegClass.hasSubClassEq(RC))
    Opc = Mips::LOAD_ACC64DSP;
  else if (Mips::ACC128RegClass.hasSubClassEq(RC))
    Opc = Mips::LOAD_ACC128;
  else if (Mips::DSPCCRegClass.hasSubClassEq(RC))
    Opc = Mips::LOAD_CCOND_DSP;
  else if (Mips::FGR32RegClass.hasSubClassEq(RC))
    Opc = Mips::LWC1;
  else if (Mips::AFGR64RegClass.hasSubClassEq(RC))
    Opc = Mips::LDC1;
  else if (Mips::FGR64RegClass.hasSubClassEq(RC))
    Opc = Mips::LDC164;
  else if (TRI->isTypeLegalForClass(*RC, MVT::v16i8))
    Opc = Mips::LD_B;
  else if (TRI->isTypeLegalForClass(*RC, MVT::v8i16) ||
           TRI->isTypeLegalForClass(*RC, MVT::v8f16))
    Opc = Mips::LD_H;
  else if (TRI->isTypeLegalForClass(*RC, MVT::v4i32) ||
           TRI->isTypeLegalForClass(*RC, MVT::v4f32))
    Opc = Mips::LD_W;
  else if (TRI->isTypeLegalForClass(*RC, MVT::v2i64) ||
           TRI->isTypeLegalForClass(*RC, MVT::v2f64))
    Opc = Mips::LD_D;
  else if (Mips::HI32RegClass.hasSubClassEq(RC))
    Opc = Mips::LW;
  else if (Mips::HI64RegClass.hasSubClassEq(RC))
    Opc = Mips::LD;
  else if (Mips::LO32RegClass.hasSubClassEq(RC))
    Opc = Mips::LW;
  else if (Mips::LO64RegClass.hasSubClassEq(RC))
    Opc = Mips::LD;

  assert(Opc && "Register class not handled!");

  if (!ReqIndirectLoad)
    BuildMI(MBB, I, DL, get(Opc), DestReg)
        .addFrameIndex(FI)
        .addImm(Offset)
        .addMemOperand(MMO);
  else {
    // Load HI/LO through K0. Notably the DestReg is encoded into the
    // instruction itself.
    unsigned Reg = Mips::K0;
    unsigned LdOp = Mips::MTLO;
    if (DestReg == Mips::HI0)
      LdOp = Mips::MTHI;

    if (Subtarget.getABI().ArePtrs64bit()) {
      Reg = Mips::K0_64;
      if (DestReg == Mips::HI0_64)
        LdOp = Mips::MTHI64;
      else
        LdOp = Mips::MTLO64;
    }

    BuildMI(MBB, I, DL, get(Opc), Reg)
        .addFrameIndex(FI)
        .addImm(Offset)
        .addMemOperand(MMO);
    BuildMI(MBB, I, DL, get(LdOp)).addReg(Reg);
  }
}
Beispiel #16
0
bool GCMachineCodeFixup::runOnMachineFunction(MachineFunction &MF) {
  // Quick exit for functions that do not use GC.
  if (!MF.getFunction()->hasGC())
    return false;

  const TargetMachine &TM = MF.getTarget();
  const TargetInstrInfo *TII = TM.getInstrInfo();
  GCModuleInfo &GMI = getAnalysis<GCModuleInfo>();
  GCFunctionInfo &GCFI = GMI.getFunctionInfo(*MF.getFunction());

  for (MachineFunction::iterator MBBI = MF.begin(),
                                 MBBE = MF.end(); MBBI != MBBE; ++MBBI) {
    for (MachineBasicBlock::iterator MII = MBBI->begin(),
                                     MIE = MBBI->end(); MII != MIE;) {
      if (!MII->isGCRegRoot() || !MII->getOperand(0).isReg()) {
        ++MII;
        continue;
      }

      // Trace the register back to its location at the site of the call (either
      // a physical reg or a frame index).
      bool TracingReg = true;
      unsigned TracedReg = MII->getOperand(0).getReg();
      int FrameIndex;

      MachineBasicBlock::iterator PrevII = MII;
      for (--PrevII;; --PrevII) {
        if (PrevII->isGCRegRoot() && PrevII->getOperand(0).isReg())
          break;
        if (PrevII->isCall())
          break;

        int FI;

        // Trace back through register reloads.
        unsigned Reg =
          TM.getInstrInfo()->isLoadFromStackSlotPostFE(&*PrevII, FI);
        if (Reg) {
          // This is a reload. If we're tracing this register, start tracing the
          // frame index instead.
          if (TracingReg && TracedReg == Reg) {
            TracingReg = false;
            FrameIndex = FI;
          }
          continue;
        }

        // Trace back through spills.
        if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&*PrevII, FI))
          continue;

        // Trace back through register-to-register copies.
        if (PrevII->isCopy()) {
          if (TracingReg && TracedReg == PrevII->getOperand(0).getReg())
            TracedReg = PrevII->getOperand(1).getReg();
          continue;
        }

        // Trace back through non-register GC_REG_ROOT instructions.
        if (PrevII->isGCRegRoot() && !PrevII->getOperand(0).isReg())
          continue;

        DEBUG(dbgs() << "Bad instruction: " << *PrevII);
        llvm_unreachable("GC_REG_ROOT found in an unexpected location!");
      }

      // Now we've reached either a call or another GC_REG_ROOT instruction.
      // Move the GC_REG_ROOT instruction we're considering to the right place,
      // and rewrite it if necessary.
      //
      // Also, tell the GCFunctionInfo about the frame index, since this is
      // our only chance -- the frame indices will be deleted by the time
      // GCMachineCodeAnalysis runs.
      ++PrevII;
      unsigned RootIndex = MII->getOperand(1).getImm();
      MachineInstr *NewMI;
      if (TracingReg) {
        MachineInstrBuilder MIB = BuildMI(MF, MII->getDebugLoc(),
                                          TII->get(TargetOpcode::GC_REG_ROOT));
        MIB.addReg(TracedReg).addImm(RootIndex);
        NewMI = MIB;
      } else {
        NewMI = TII->emitFrameIndexGCRegRoot(MF, FrameIndex, RootIndex,
                                             MII->getDebugLoc());
        GCFI.spillRegRoot(RootIndex, FrameIndex);
      }

      MBBI->insert(PrevII, NewMI);

      MachineBasicBlock::iterator NextII = MII;
      ++NextII;
      MII->eraseFromParent();
      MII = NextII;
    }
  }

  return true;
}
Beispiel #17
0
void MipsSEInstrInfo::expandERet(MachineBasicBlock &MBB,
                                 MachineBasicBlock::iterator I) const {
  BuildMI(MBB, I, I->getDebugLoc(), get(Mips::ERET));
}
void PEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
                              int &SPAdj) {
  assert(Fn.getSubtarget().getRegisterInfo() &&
         "getRegisterInfo() must be implemented!");
  const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
  const TargetRegisterInfo &TRI = *Fn.getSubtarget().getRegisterInfo();
  const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
  unsigned FrameSetupOpcode = TII.getCallFrameSetupOpcode();
  unsigned FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();

  if (RS && !FrameIndexVirtualScavenging) RS->enterBasicBlock(*BB);

  bool InsideCallSequence = false;

  for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {

    if (I->getOpcode() == FrameSetupOpcode ||
        I->getOpcode() == FrameDestroyOpcode) {
      InsideCallSequence = (I->getOpcode() == FrameSetupOpcode);
      SPAdj += TII.getSPAdjust(I);

      I = TFI->eliminateCallFramePseudoInstr(Fn, *BB, I);
      continue;
    }

    MachineInstr *MI = I;
    bool DoIncr = true;
    for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
      if (!MI->getOperand(i).isFI())
        continue;

      // Frame indices in debug values are encoded in a target independent
      // way with simply the frame index and offset rather than any
      // target-specific addressing mode.
      if (MI->isDebugValue()) {
        assert(i == 0 && "Frame indices can only appear as the first "
                         "operand of a DBG_VALUE machine instruction");
        unsigned Reg;
        MachineOperand &Offset = MI->getOperand(1);
        Offset.setImm(Offset.getImm() +
                      TFI->getFrameIndexReference(
                          Fn, MI->getOperand(0).getIndex(), Reg));
        MI->getOperand(0).ChangeToRegister(Reg, false /*isDef*/);
        continue;
      }

      // TODO: This code should be commoned with the code for
      // PATCHPOINT. There's no good reason for the difference in
      // implementation other than historical accident.  The only
      // remaining difference is the unconditional use of the stack
      // pointer as the base register.
      if (MI->getOpcode() == TargetOpcode::STATEPOINT) {
        assert((!MI->isDebugValue() || i == 0) &&
               "Frame indicies can only appear as the first operand of a "
               "DBG_VALUE machine instruction");
        unsigned Reg;
        MachineOperand &Offset = MI->getOperand(i + 1);
        const unsigned refOffset =
          TFI->getFrameIndexReferenceFromSP(Fn, MI->getOperand(i).getIndex(),
                                            Reg);

        Offset.setImm(Offset.getImm() + refOffset);
        MI->getOperand(i).ChangeToRegister(Reg, false /*isDef*/);
        continue;
      }

      // Some instructions (e.g. inline asm instructions) can have
      // multiple frame indices and/or cause eliminateFrameIndex
      // to insert more than one instruction. We need the register
      // scavenger to go through all of these instructions so that
      // it can update its register information. We keep the
      // iterator at the point before insertion so that we can
      // revisit them in full.
      bool AtBeginning = (I == BB->begin());
      if (!AtBeginning) --I;

      // If this instruction has a FrameIndex operand, we need to
      // use that target machine register info object to eliminate
      // it.
      TRI.eliminateFrameIndex(MI, SPAdj, i,
                              FrameIndexVirtualScavenging ?  nullptr : RS);

      // Reset the iterator if we were at the beginning of the BB.
      if (AtBeginning) {
        I = BB->begin();
        DoIncr = false;
      }

      MI = nullptr;
      break;
    }

    // If we are looking at a call sequence, we need to keep track of
    // the SP adjustment made by each instruction in the sequence.
    // This includes both the frame setup/destroy pseudos (handled above),
    // as well as other instructions that have side effects w.r.t the SP.
    // Note that this must come after eliminateFrameIndex, because 
    // if I itself referred to a frame index, we shouldn't count its own
    // adjustment.
    if (MI && InsideCallSequence)
      SPAdj += TII.getSPAdjust(MI);

    if (DoIncr && I != BB->end()) ++I;

    // Update register states.
    if (RS && !FrameIndexVirtualScavenging && MI) RS->forward(MI);
  }
}
Beispiel #19
0
static bool combineRestoreOR(MachineBasicBlock::iterator RestoreMI,
                             MachineBasicBlock::iterator OrMI,
                             const TargetInstrInfo *TII)
{
  // Before:  or  <op0>, <op1>, %i[0-7]
  //          restore %g0, %g0, %i[0-7]
  //    and <op0> or <op1> is zero,
  //
  // After :  restore <op0>, <op1>, %o[0-7]

  unsigned reg = OrMI->getOperand(0).getReg();
  if (reg < SP::I0 || reg > SP::I7)
    return false;

  // check whether it is a copy.
  if (OrMI->getOpcode() == SP::ORrr
      && OrMI->getOperand(1).getReg() != SP::G0
      && OrMI->getOperand(2).getReg() != SP::G0)
    return false;

  if (OrMI->getOpcode() == SP::ORri
      && OrMI->getOperand(1).getReg() != SP::G0
      && (!OrMI->getOperand(2).isImm() || OrMI->getOperand(2).getImm() != 0))
    return false;

  // Erase RESTORE.
  RestoreMI->eraseFromParent();

  // Change OR to RESTORE.
  OrMI->setDesc(TII->get((OrMI->getOpcode() == SP::ORrr)
                         ? SP::RESTORErr
                         : SP::RESTOREri));

  // Map the destination register.
  OrMI->getOperand(0).setReg(reg - SP::I0 + SP::O0);

  return true;
}
Beispiel #20
0
/// AnalyzeBranch - Analyze the branching code at the end of MBB, returning
/// true if it cannot be understood (e.g. it's a switch dispatch or isn't
/// implemented for a target).  Upon success, this returns false and returns
/// with the following information in various cases:
///
/// 1. If this block ends with no branches (it just falls through to its succ)
///    just return false, leaving TBB/FBB null.
/// 2. If this block ends with only an unconditional branch, it sets TBB to be
///    the destination block.
/// 3. If this block ends with an conditional branch and it falls through to
///    an successor block, it sets TBB to be the branch destination block and a
///    list of operands that evaluate the condition. These
///    operands can be passed to other TargetInstrInfo methods to create new
///    branches.
/// 4. If this block ends with an conditional branch and an unconditional
///    block, it returns the 'true' destination in TBB, the 'false' destination
///    in FBB, and a list of operands that evaluate the condition. These
///    operands can be passed to other TargetInstrInfo methods to create new
///    branches.
///
/// Note that RemoveBranch and InsertBranch must be implemented to support
/// cases where this method returns success.
///
bool
XCoreInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
                              MachineBasicBlock *&FBB,
                              SmallVectorImpl<MachineOperand> &Cond,
                              bool AllowModify) const {
  // If the block has no terminators, it just falls into the block after it.
  MachineBasicBlock::iterator I = MBB.end();
  if (I == MBB.begin())
    return false;
  --I;
  while (I->isDebugValue()) {
    if (I == MBB.begin())
      return false;
    --I;
  }
  if (!isUnpredicatedTerminator(I))
    return false;

  // Get the last instruction in the block.
  MachineInstr *LastInst = I;
  
  // If there is only one terminator instruction, process it.
  if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
    if (IsBRU(LastInst->getOpcode())) {
      TBB = LastInst->getOperand(0).getMBB();
      return false;
    }
    
    XCore::CondCode BranchCode = GetCondFromBranchOpc(LastInst->getOpcode());
    if (BranchCode == XCore::COND_INVALID)
      return true;  // Can't handle indirect branch.
    
    // Conditional branch
    // Block ends with fall-through condbranch.

    TBB = LastInst->getOperand(1).getMBB();
    Cond.push_back(MachineOperand::CreateImm(BranchCode));
    Cond.push_back(LastInst->getOperand(0));
    return false;
  }
  
  // Get the instruction before it if it's a terminator.
  MachineInstr *SecondLastInst = I;

  // If there are three terminators, we don't know what sort of block this is.
  if (SecondLastInst && I != MBB.begin() &&
      isUnpredicatedTerminator(--I))
    return true;
  
  unsigned SecondLastOpc    = SecondLastInst->getOpcode();
  XCore::CondCode BranchCode = GetCondFromBranchOpc(SecondLastOpc);
  
  // If the block ends with conditional branch followed by unconditional,
  // handle it.
  if (BranchCode != XCore::COND_INVALID
    && IsBRU(LastInst->getOpcode())) {

    TBB = SecondLastInst->getOperand(1).getMBB();
    Cond.push_back(MachineOperand::CreateImm(BranchCode));
    Cond.push_back(SecondLastInst->getOperand(0));

    FBB = LastInst->getOperand(0).getMBB();
    return false;
  }
  
  // If the block ends with two unconditional branches, handle it.  The second
  // one is not executed, so remove it.
  if (IsBRU(SecondLastInst->getOpcode()) && 
      IsBRU(LastInst->getOpcode())) {
    TBB = SecondLastInst->getOperand(0).getMBB();
    I = LastInst;
    if (AllowModify)
      I->eraseFromParent();
    return false;
  }

  // Likewise if it ends with a branch table followed by an unconditional branch.
  if (IsBR_JT(SecondLastInst->getOpcode()) && IsBRU(LastInst->getOpcode())) {
    I = LastInst;
    if (AllowModify)
      I->eraseFromParent();
    return true;
  }

  // Otherwise, can't handle this.
  return true;
}
void MipsSEFrameLowering::emitPrologue(MachineFunction &MF,
                                       MachineBasicBlock &MBB) const {
  assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported");
  MachineFrameInfo *MFI    = MF.getFrameInfo();
  MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();

  const MipsSEInstrInfo &TII =
      *static_cast<const MipsSEInstrInfo *>(STI.getInstrInfo());
  const MipsRegisterInfo &RegInfo =
      *static_cast<const MipsRegisterInfo *>(STI.getRegisterInfo());

  MachineBasicBlock::iterator MBBI = MBB.begin();
  DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
  MipsABIInfo ABI = STI.getABI();
  unsigned SP = ABI.GetStackPtr();
  unsigned FP = ABI.GetFramePtr();
  unsigned ZERO = ABI.GetNullPtr();
  unsigned ADDu = ABI.GetPtrAdduOp();
  unsigned ADDiu = ABI.GetPtrAddiuOp();
  unsigned AND = ABI.IsN64() ? Mips::AND64 : Mips::AND;

  const TargetRegisterClass *RC = ABI.ArePtrs64bit() ?
        &Mips::GPR64RegClass : &Mips::GPR32RegClass;

  // First, compute final stack size.
  uint64_t StackSize = MFI->getStackSize();

  // No need to allocate space on the stack.
  if (StackSize == 0 && !MFI->adjustsStack()) return;

  MachineModuleInfo &MMI = MF.getMMI();
  const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo();
  MachineLocation DstML, SrcML;

  // Adjust stack.
  TII.adjustStackPtr(SP, -StackSize, MBB, MBBI);

  // emit ".cfi_def_cfa_offset StackSize"
  unsigned CFIIndex = MMI.addFrameInst(
      MCCFIInstruction::createDefCfaOffset(nullptr, -StackSize));
  BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
      .addCFIIndex(CFIIndex);

  const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();

  if (CSI.size()) {
    // Find the instruction past the last instruction that saves a callee-saved
    // register to the stack.
    for (unsigned i = 0; i < CSI.size(); ++i)
      ++MBBI;

    // Iterate over list of callee-saved registers and emit .cfi_offset
    // directives.
    for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
           E = CSI.end(); I != E; ++I) {
      int64_t Offset = MFI->getObjectOffset(I->getFrameIdx());
      unsigned Reg = I->getReg();

      // If Reg is a double precision register, emit two cfa_offsets,
      // one for each of the paired single precision registers.
      if (Mips::AFGR64RegClass.contains(Reg)) {
        unsigned Reg0 =
            MRI->getDwarfRegNum(RegInfo.getSubReg(Reg, Mips::sub_lo), true);
        unsigned Reg1 =
            MRI->getDwarfRegNum(RegInfo.getSubReg(Reg, Mips::sub_hi), true);

        if (!STI.isLittle())
          std::swap(Reg0, Reg1);

        unsigned CFIIndex = MMI.addFrameInst(
            MCCFIInstruction::createOffset(nullptr, Reg0, Offset));
        BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
            .addCFIIndex(CFIIndex);

        CFIIndex = MMI.addFrameInst(
            MCCFIInstruction::createOffset(nullptr, Reg1, Offset + 4));
        BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
            .addCFIIndex(CFIIndex);
      } else if (Mips::FGR64RegClass.contains(Reg)) {
        unsigned Reg0 = MRI->getDwarfRegNum(Reg, true);
        unsigned Reg1 = MRI->getDwarfRegNum(Reg, true) + 1;

        if (!STI.isLittle())
          std::swap(Reg0, Reg1);

        unsigned CFIIndex = MMI.addFrameInst(
          MCCFIInstruction::createOffset(nullptr, Reg0, Offset));
        BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
            .addCFIIndex(CFIIndex);

        CFIIndex = MMI.addFrameInst(
          MCCFIInstruction::createOffset(nullptr, Reg1, Offset + 4));
        BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
            .addCFIIndex(CFIIndex);
      } else {
        // Reg is either in GPR32 or FGR32.
        unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset(
            nullptr, MRI->getDwarfRegNum(Reg, 1), Offset));
        BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
            .addCFIIndex(CFIIndex);
      }
    }
  }

  if (MipsFI->callsEhReturn()) {
    // Insert instructions that spill eh data registers.
    for (int I = 0; I < 4; ++I) {
      if (!MBB.isLiveIn(ABI.GetEhDataReg(I)))
        MBB.addLiveIn(ABI.GetEhDataReg(I));
      TII.storeRegToStackSlot(MBB, MBBI, ABI.GetEhDataReg(I), false,
                              MipsFI->getEhDataRegFI(I), RC, &RegInfo);
    }

    // Emit .cfi_offset directives for eh data registers.
    for (int I = 0; I < 4; ++I) {
      int64_t Offset = MFI->getObjectOffset(MipsFI->getEhDataRegFI(I));
      unsigned Reg = MRI->getDwarfRegNum(ABI.GetEhDataReg(I), true);
      unsigned CFIIndex = MMI.addFrameInst(
          MCCFIInstruction::createOffset(nullptr, Reg, Offset));
      BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
          .addCFIIndex(CFIIndex);
    }
  }

  // if framepointer enabled, set it to point to the stack pointer.
  if (hasFP(MF)) {
    // Insert instruction "move $fp, $sp" at this location.
    BuildMI(MBB, MBBI, dl, TII.get(ADDu), FP).addReg(SP).addReg(ZERO)
      .setMIFlag(MachineInstr::FrameSetup);

    // emit ".cfi_def_cfa_register $fp"
    unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createDefCfaRegister(
        nullptr, MRI->getDwarfRegNum(FP, true)));
    BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
        .addCFIIndex(CFIIndex);

    if (RegInfo.needsStackRealignment(MF)) {
      // addiu $Reg, $zero, -MaxAlignment
      // andi $sp, $sp, $Reg
      unsigned VR = MF.getRegInfo().createVirtualRegister(RC);
      assert(isInt<16>(MFI->getMaxAlignment()) &&
             "Function's alignment size requirement is not supported.");
      int MaxAlign = - (signed) MFI->getMaxAlignment();

      BuildMI(MBB, MBBI, dl, TII.get(ADDiu), VR).addReg(ZERO) .addImm(MaxAlign);
      BuildMI(MBB, MBBI, dl, TII.get(AND), SP).addReg(SP).addReg(VR);

      if (hasBP(MF)) {
        // move $s7, $sp
        unsigned BP = STI.isABI_N64() ? Mips::S7_64 : Mips::S7;
        BuildMI(MBB, MBBI, dl, TII.get(ADDu), BP)
          .addReg(SP)
          .addReg(ZERO);
      }
    }
  }
}
Beispiel #22
0
/// converToHardwareLoop - check if the loop is a candidate for
/// converting to a hardware loop.  If so, then perform the
/// transformation.
///
/// This function works on innermost loops first.  A loop can
/// be converted if it is a counting loop; either a register
/// value or an immediate.
///
/// The code makes several assumptions about the representation
/// of the loop in llvm.
bool HexagonHardwareLoops::convertToHardwareLoop(MachineLoop *L) {
  bool Changed = false;
  // Process nested loops first.
  for (MachineLoop::iterator I = L->begin(), E = L->end(); I != E; ++I) {
    Changed |= convertToHardwareLoop(*I);
  }
  // If a nested loop has been converted, then we can't convert this loop.
  if (Changed) {
    return Changed;
  }
  // Are we able to determine the trip count for the loop?
  CountValue *TripCount = getTripCount(L);
  if (TripCount == 0) {
    return false;
  }
  // Does the loop contain any invalid instructions?
  if (containsInvalidInstruction(L)) {
    return false;
  }
  MachineBasicBlock *Preheader = L->getLoopPreheader();
  // No preheader means there's not place for the loop instr.
  if (Preheader == 0) {
    return false;
  }
  MachineBasicBlock::iterator InsertPos = Preheader->getFirstTerminator();

  MachineBasicBlock *LastMBB = L->getExitingBlock();
  // Don't generate hw loop if the loop has more than one exit.
  if (LastMBB == 0) {
    return false;
  }
  MachineBasicBlock::iterator LastI = LastMBB->getFirstTerminator();

  // Determine the loop start.
  MachineBasicBlock *LoopStart = L->getTopBlock();
  if (L->getLoopLatch() != LastMBB) {
    // When the exit and latch are not the same, use the latch block as the
    // start.
    // The loop start address is used only after the 1st iteration, and the loop
    // latch may contains instrs. that need to be executed after the 1st iter.
    LoopStart = L->getLoopLatch();
    // Make sure the latch is a successor of the exit, otherwise it won't work.
    if (!LastMBB->isSuccessor(LoopStart)) {
      return false;
    }
  }

  // Convert the loop to a hardware loop
  DEBUG(dbgs() << "Change to hardware loop at "; L->dump());

  if (TripCount->isReg()) {
    // Create a copy of the loop count register.
    MachineFunction *MF = LastMBB->getParent();
    const TargetRegisterClass *RC =
      MF->getRegInfo().getRegClass(TripCount->getReg());
    unsigned CountReg = MF->getRegInfo().createVirtualRegister(RC);
    BuildMI(*Preheader, InsertPos, InsertPos->getDebugLoc(),
            TII->get(TargetOpcode::COPY), CountReg).addReg(TripCount->getReg());
    if (TripCount->isNeg()) {
      unsigned CountReg1 = CountReg;
      CountReg = MF->getRegInfo().createVirtualRegister(RC);
      BuildMI(*Preheader, InsertPos, InsertPos->getDebugLoc(),
              TII->get(Hexagon::NEG), CountReg).addReg(CountReg1);
    }

    // Add the Loop instruction to the begining of the loop.
    BuildMI(*Preheader, InsertPos, InsertPos->getDebugLoc(),
            TII->get(Hexagon::LOOP0_r)).addMBB(LoopStart).addReg(CountReg);
  } else {
    assert(TripCount->isImm() && "Expecting immedate vaule for trip count");
    // Add the Loop immediate instruction to the beginning of the loop.
    int64_t CountImm = TripCount->getImm();
    BuildMI(*Preheader, InsertPos, InsertPos->getDebugLoc(),
            TII->get(Hexagon::LOOP0_i)).addMBB(LoopStart).addImm(CountImm);
  }

  // Make sure the loop start always has a reference in the CFG.  We need to
  // create a BlockAddress operand to get this mechanism to work both the
  // MachineBasicBlock and BasicBlock objects need the flag set.
  LoopStart->setHasAddressTaken();
  // This line is needed to set the hasAddressTaken flag on the BasicBlock
  // object
  BlockAddress::get(const_cast<BasicBlock *>(LoopStart->getBasicBlock()));

  // Replace the loop branch with an endloop instruction.
  DebugLoc dl = LastI->getDebugLoc();
  BuildMI(*LastMBB, LastI, dl, TII->get(Hexagon::ENDLOOP0)).addMBB(LoopStart);

  // The loop ends with either:
  //  - a conditional branch followed by an unconditional branch, or
  //  - a conditional branch to the loop start.
  if (LastI->getOpcode() == Hexagon::JMP_c ||
      LastI->getOpcode() == Hexagon::JMP_cNot) {
    // delete one and change/add an uncond. branch to out of the loop
    MachineBasicBlock *BranchTarget = LastI->getOperand(1).getMBB();
    LastI = LastMBB->erase(LastI);
    if (!L->contains(BranchTarget)) {
      if (LastI != LastMBB->end()) {
        TII->RemoveBranch(*LastMBB);
      }
      SmallVector<MachineOperand, 0> Cond;
      TII->InsertBranch(*LastMBB, BranchTarget, 0, Cond, dl);
    }
  } else {
    // Conditional branch to loop start; just delete it.
    LastMBB->erase(LastI);
  }
  delete TripCount;

  ++NumHWLoops;
  return true;
}
Beispiel #23
0
// Branch analysis.
bool
LembergInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,
								MachineBasicBlock *&TBB,
                                MachineBasicBlock *&FBB,
                                SmallVectorImpl<MachineOperand> &Cond,
                                bool AllowModify) const {

	// If the block has no terminators, it just falls into the block after it.
	MachineBasicBlock::iterator I = MBB.end();
	if (I == MBB.begin() || !isUnpredicatedTerminator(--I))
		return false;

	// Get the last instruction in the block.
	MachineInstr *LastInst = I;

	// If there is only one terminator instruction, process it.
	unsigned LastOpc = LastInst->getOpcode();
	if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
		if (LastOpc == Lemberg::JUMP) {
			TBB = LastInst->getOperand(0).getMBB();
			return false;
		}
		if (LastOpc == Lemberg::JUMPtrue) {
			TBB = LastInst->getOperand(1).getMBB();
			Cond.push_back(LastInst->getOperand(0));
			Cond.push_back(MachineOperand::CreateImm(LembergCC::TRUE));
			return false;
		}
		if (LastOpc == Lemberg::JUMPfalse) {
			TBB = LastInst->getOperand(1).getMBB();
			Cond.push_back(LastInst->getOperand(0));
			Cond.push_back(MachineOperand::CreateImm(LembergCC::FALSE));
			return false;
		}
		if (LastOpc == Lemberg::JUMPpred) {
			TBB = LastInst->getOperand(2).getMBB();
			Cond.push_back(LastInst->getOperand(1));
			Cond.push_back(LastInst->getOperand(0));
			return false;
		}
		if (LastOpc == Lemberg::JUMPeqz
			|| LastOpc == Lemberg::JUMPnez
			|| LastOpc == Lemberg::JUMPltz
			|| LastOpc == Lemberg::JUMPgez
			|| LastOpc == Lemberg::JUMPgtz
			|| LastOpc == Lemberg::JUMPlez) {
		  TBB = LastInst->getOperand(1).getMBB();
		  LembergCC::CondCode Code;
		  switch (LastOpc) {
		  case Lemberg::JUMPeqz: Code = LembergCC::EQZ; break;
		  case Lemberg::JUMPnez: Code = LembergCC::NEZ; break;
		  case Lemberg::JUMPltz: Code = LembergCC::LTZ; break;
		  case Lemberg::JUMPgez: Code = LembergCC::GEZ; break;
		  case Lemberg::JUMPgtz: Code = LembergCC::GTZ; break;
		  case Lemberg::JUMPlez: Code = LembergCC::LEZ; break;
		  }
		  Cond.push_back(LastInst->getOperand(0));
		  Cond.push_back(MachineOperand::CreateImm(Code));
		  return false;
		}

		return true;  // Can't handle indirect branch.
	}

	// Get the instruction before it if it's a terminator.
	MachineInstr *SecondLastInst = I;
	
	// If there are three terminators, we don't know what sort of block this is.
	if (SecondLastInst && I != MBB.begin() &&
		isUnpredicatedTerminator(--I)) {
		return true;
	}

	// If the block ends with JUMP, JUMPtrue, JUMPfalse, or JUMPpred, handle it.
	if (LastInst->getOpcode() == Lemberg::JUMP) {
		if (SecondLastInst->getOpcode() == Lemberg::JUMPtrue) {
			TBB =  SecondLastInst->getOperand(1).getMBB();
			Cond.push_back(SecondLastInst->getOperand(0));
			Cond.push_back(MachineOperand::CreateImm(LembergCC::TRUE));
			FBB = LastInst->getOperand(0).getMBB();
			return false;
		}
		if (SecondLastInst->getOpcode() == Lemberg::JUMPfalse) {
			TBB =  SecondLastInst->getOperand(1).getMBB();
			Cond.push_back(SecondLastInst->getOperand(0));
			Cond.push_back(MachineOperand::CreateImm(LembergCC::FALSE));
			FBB = LastInst->getOperand(0).getMBB();
			return false;
		}
		if (SecondLastInst->getOpcode() == Lemberg::JUMPpred) {
			TBB = SecondLastInst->getOperand(2).getMBB();
			Cond.push_back(SecondLastInst->getOperand(1));
			Cond.push_back(SecondLastInst->getOperand(0));
			FBB = LastInst->getOperand(0).getMBB();
			return false;
		}
		if (SecondLastInst->getOpcode() == Lemberg::JUMPeqz
			|| SecondLastInst->getOpcode() == Lemberg::JUMPnez
			|| SecondLastInst->getOpcode() == Lemberg::JUMPltz
			|| SecondLastInst->getOpcode() == Lemberg::JUMPgez
			|| SecondLastInst->getOpcode() == Lemberg::JUMPgtz
			|| SecondLastInst->getOpcode() == Lemberg::JUMPlez) {
		  TBB = SecondLastInst->getOperand(1).getMBB();
		  LembergCC::CondCode Code;
		  switch (SecondLastInst->getOpcode()) {
		  case Lemberg::JUMPeqz: Code = LembergCC::EQZ; break;
		  case Lemberg::JUMPnez: Code = LembergCC::NEZ; break;
		  case Lemberg::JUMPltz: Code = LembergCC::LTZ; break;
		  case Lemberg::JUMPgez: Code = LembergCC::GEZ; break;
		  case Lemberg::JUMPgtz: Code = LembergCC::GTZ; break;
		  case Lemberg::JUMPlez: Code = LembergCC::LEZ; break;
		  }
		  Cond.push_back(SecondLastInst->getOperand(0));
		  Cond.push_back(MachineOperand::CreateImm(Code));
		  FBB = LastInst->getOperand(0).getMBB();
		  return false;
		}
	}

	// If the block ends with two JUMPs, handle it. The second one is
	// not executed, so remove it.
	if (SecondLastInst->getOpcode() == Lemberg::JUMP && 
		LastInst->getOpcode() == Lemberg::JUMP) {
		TBB = SecondLastInst->getOperand(0).getMBB();
		I = LastInst;
		if (AllowModify)
			I->eraseFromParent();
		return false;
	}

	// Otherwise, can't handle this.
	return true;
}
MachineBasicBlock::iterator
AArch64LoadStoreOpt::mergePairedInsns(MachineBasicBlock::iterator I,
                                      MachineBasicBlock::iterator Paired,
                                      const LdStPairFlags &Flags) {
  MachineBasicBlock::iterator NextI = I;
  ++NextI;
  // If NextI is the second of the two instructions to be merged, we need
  // to skip one further. Either way we merge will invalidate the iterator,
  // and we don't need to scan the new instruction, as it's a pairwise
  // instruction, which we're not considering for further action anyway.
  if (NextI == Paired)
    ++NextI;

  int SExtIdx = Flags.getSExtIdx();
  unsigned Opc =
      SExtIdx == -1 ? I->getOpcode() : getMatchingNonSExtOpcode(I->getOpcode());
  bool IsUnscaled = isUnscaledLdSt(Opc);
  int OffsetStride = IsUnscaled ? getMemScale(I) : 1;

  bool MergeForward = Flags.getMergeForward();
  unsigned NewOpc = getMatchingPairOpcode(Opc);
  // Insert our new paired instruction after whichever of the paired
  // instructions MergeForward indicates.
  MachineBasicBlock::iterator InsertionPoint = MergeForward ? Paired : I;
  // Also based on MergeForward is from where we copy the base register operand
  // so we get the flags compatible with the input code.
  const MachineOperand &BaseRegOp =
      MergeForward ? getLdStBaseOp(Paired) : getLdStBaseOp(I);

  // Which register is Rt and which is Rt2 depends on the offset order.
  MachineInstr *RtMI, *Rt2MI;
  if (getLdStOffsetOp(I).getImm() ==
      getLdStOffsetOp(Paired).getImm() + OffsetStride) {
    RtMI = Paired;
    Rt2MI = I;
    // Here we swapped the assumption made for SExtIdx.
    // I.e., we turn ldp I, Paired into ldp Paired, I.
    // Update the index accordingly.
    if (SExtIdx != -1)
      SExtIdx = (SExtIdx + 1) % 2;
  } else {
    RtMI = I;
    Rt2MI = Paired;
  }

  int OffsetImm = getLdStOffsetOp(RtMI).getImm();

  if (isSmallTypeLdMerge(Opc)) {
    // Change the scaled offset from small to large type.
    if (!IsUnscaled)
      OffsetImm /= 2;
    MachineInstr *RtNewDest = MergeForward ? I : Paired;
    // Construct the new load instruction.
    // FIXME: currently we support only halfword unsigned load. We need to
    // handle byte type, signed, and store instructions as well.
    MachineInstr *NewMemMI, *BitExtMI1, *BitExtMI2;
    NewMemMI = BuildMI(*I->getParent(), I, I->getDebugLoc(), TII->get(NewOpc))
                   .addOperand(getLdStRegOp(RtNewDest))
                   .addOperand(BaseRegOp)
                   .addImm(OffsetImm);

    // Copy MachineMemOperands from the original loads.
    concatenateMemOperands(NewMemMI, I, Paired);

    DEBUG(
        dbgs()
        << "Creating the new load and extract. Replacing instructions:\n    ");
    DEBUG(I->print(dbgs()));
    DEBUG(dbgs() << "    ");
    DEBUG(Paired->print(dbgs()));
    DEBUG(dbgs() << "  with instructions:\n    ");
    DEBUG((NewMemMI)->print(dbgs()));

    MachineInstr *ExtDestMI = MergeForward ? Paired : I;
    if (ExtDestMI == Rt2MI) {
      // Create the bitfield extract for high half.
      BitExtMI1 = BuildMI(*I->getParent(), InsertionPoint, I->getDebugLoc(),
                          TII->get(AArch64::UBFMWri))
                      .addOperand(getLdStRegOp(Rt2MI))
                      .addReg(getLdStRegOp(RtNewDest).getReg())
                      .addImm(16)
                      .addImm(31);
      // Create the bitfield extract for low half.
      BitExtMI2 = BuildMI(*I->getParent(), InsertionPoint, I->getDebugLoc(),
                          TII->get(AArch64::ANDWri))
                      .addOperand(getLdStRegOp(RtMI))
                      .addReg(getLdStRegOp(RtNewDest).getReg())
                      .addImm(15);
    } else {
      // Create the bitfield extract for low half.
      BitExtMI1 = BuildMI(*I->getParent(), InsertionPoint, I->getDebugLoc(),
                          TII->get(AArch64::ANDWri))
                      .addOperand(getLdStRegOp(RtMI))
                      .addReg(getLdStRegOp(RtNewDest).getReg())
                      .addImm(15);
      // Create the bitfield extract for high half.
      BitExtMI2 = BuildMI(*I->getParent(), InsertionPoint, I->getDebugLoc(),
                          TII->get(AArch64::UBFMWri))
                      .addOperand(getLdStRegOp(Rt2MI))
                      .addReg(getLdStRegOp(RtNewDest).getReg())
                      .addImm(16)
                      .addImm(31);
    }
    DEBUG(dbgs() << "    ");
    DEBUG((BitExtMI1)->print(dbgs()));
    DEBUG(dbgs() << "    ");
    DEBUG((BitExtMI2)->print(dbgs()));
    DEBUG(dbgs() << "\n");

    // Erase the old instructions.
    I->eraseFromParent();
    Paired->eraseFromParent();
    return NextI;
  }

  // Handle Unscaled
  if (IsUnscaled)
    OffsetImm /= OffsetStride;

  // Construct the new instruction.
  MachineInstrBuilder MIB = BuildMI(*I->getParent(), InsertionPoint,
                                    I->getDebugLoc(), TII->get(NewOpc))
                                .addOperand(getLdStRegOp(RtMI))
                                .addOperand(getLdStRegOp(Rt2MI))
                                .addOperand(BaseRegOp)
                                .addImm(OffsetImm);
  (void)MIB;

  // FIXME: Do we need/want to copy the mem operands from the source
  //        instructions? Probably. What uses them after this?

  DEBUG(dbgs() << "Creating pair load/store. Replacing instructions:\n    ");
  DEBUG(I->print(dbgs()));
  DEBUG(dbgs() << "    ");
  DEBUG(Paired->print(dbgs()));
  DEBUG(dbgs() << "  with instruction:\n    ");

  if (SExtIdx != -1) {
    // Generate the sign extension for the proper result of the ldp.
    // I.e., with X1, that would be:
    // %W1<def> = KILL %W1, %X1<imp-def>
    // %X1<def> = SBFMXri %X1<kill>, 0, 31
    MachineOperand &DstMO = MIB->getOperand(SExtIdx);
    // Right now, DstMO has the extended register, since it comes from an
    // extended opcode.
    unsigned DstRegX = DstMO.getReg();
    // Get the W variant of that register.
    unsigned DstRegW = TRI->getSubReg(DstRegX, AArch64::sub_32);
    // Update the result of LDP to use the W instead of the X variant.
    DstMO.setReg(DstRegW);
    DEBUG(((MachineInstr *)MIB)->print(dbgs()));
    DEBUG(dbgs() << "\n");
    // Make the machine verifier happy by providing a definition for
    // the X register.
    // Insert this definition right after the generated LDP, i.e., before
    // InsertionPoint.
    MachineInstrBuilder MIBKill =
        BuildMI(*I->getParent(), InsertionPoint, I->getDebugLoc(),
                TII->get(TargetOpcode::KILL), DstRegW)
            .addReg(DstRegW)
            .addReg(DstRegX, RegState::Define);
    MIBKill->getOperand(2).setImplicit();
    // Create the sign extension.
    MachineInstrBuilder MIBSXTW =
        BuildMI(*I->getParent(), InsertionPoint, I->getDebugLoc(),
                TII->get(AArch64::SBFMXri), DstRegX)
            .addReg(DstRegX)
            .addImm(0)
            .addImm(31);
    (void)MIBSXTW;
    DEBUG(dbgs() << "  Extend operand:\n    ");
    DEBUG(((MachineInstr *)MIBSXTW)->print(dbgs()));
    DEBUG(dbgs() << "\n");
  } else {
    DEBUG(((MachineInstr *)MIB)->print(dbgs()));
    DEBUG(dbgs() << "\n");
  }

  // Erase the old instructions.
  I->eraseFromParent();
  Paired->eraseFromParent();

  return NextI;
}
Beispiel #25
0
/// SinkInstruction - Determine whether it is safe to sink the specified machine
/// instruction out of its current block into a successor.
bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) {
    // Don't sink insert_subreg, subreg_to_reg, reg_sequence. These are meant to
    // be close to the source to make it easier to coalesce.
    if (AvoidsSinking(MI, MRI))
        return false;

    // Check if it's safe to move the instruction.
    if (!MI->isSafeToMove(TII, AA, SawStore))
        return false;

    // FIXME: This should include support for sinking instructions within the
    // block they are currently in to shorten the live ranges.  We often get
    // instructions sunk into the top of a large block, but it would be better to
    // also sink them down before their first use in the block.  This xform has to
    // be careful not to *increase* register pressure though, e.g. sinking
    // "x = y + z" down if it kills y and z would increase the live ranges of y
    // and z and only shrink the live range of x.

    bool BreakPHIEdge = false;
    MachineBasicBlock *ParentBlock = MI->getParent();
    MachineBasicBlock *SuccToSinkTo = FindSuccToSinkTo(MI, ParentBlock, BreakPHIEdge);

    // If there are no outputs, it must have side-effects.
    if (!SuccToSinkTo)
        return false;


    // If the instruction to move defines a dead physical register which is live
    // when leaving the basic block, don't move it because it could turn into a
    // "zombie" define of that preg. E.g., EFLAGS. (<rdar://problem/8030636>)
    for (unsigned I = 0, E = MI->getNumOperands(); I != E; ++I) {
        const MachineOperand &MO = MI->getOperand(I);
        if (!MO.isReg()) continue;
        unsigned Reg = MO.getReg();
        if (Reg == 0 || !TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
        if (SuccToSinkTo->isLiveIn(Reg))
            return false;
    }

    DEBUG(dbgs() << "Sink instr " << *MI << "\tinto block " << *SuccToSinkTo);

    // If the block has multiple predecessors, this is a critical edge.
    // Decide if we can sink along it or need to break the edge.
    if (SuccToSinkTo->pred_size() > 1) {
        // We cannot sink a load across a critical edge - there may be stores in
        // other code paths.
        bool TryBreak = false;
        bool store = true;
        if (!MI->isSafeToMove(TII, AA, store)) {
            DEBUG(dbgs() << " *** NOTE: Won't sink load along critical edge.\n");
            TryBreak = true;
        }

        // We don't want to sink across a critical edge if we don't dominate the
        // successor. We could be introducing calculations to new code paths.
        if (!TryBreak && !DT->dominates(ParentBlock, SuccToSinkTo)) {
            DEBUG(dbgs() << " *** NOTE: Critical edge found\n");
            TryBreak = true;
        }

        // Don't sink instructions into a loop.
        if (!TryBreak && LI->isLoopHeader(SuccToSinkTo)) {
            DEBUG(dbgs() << " *** NOTE: Loop header found\n");
            TryBreak = true;
        }

        // Otherwise we are OK with sinking along a critical edge.
        if (!TryBreak)
            DEBUG(dbgs() << "Sinking along critical edge.\n");
        else {
            // Mark this edge as to be split.
            // If the edge can actually be split, the next iteration of the main loop
            // will sink MI in the newly created block.
            bool Status =
                PostponeSplitCriticalEdge(MI, ParentBlock, SuccToSinkTo, BreakPHIEdge);
            if (!Status)
                DEBUG(dbgs() << " *** PUNTING: Not legal or profitable to "
                      "break critical edge\n");
            // The instruction will not be sunk this time.
            return false;
        }
    }

    if (BreakPHIEdge) {
        // BreakPHIEdge is true if all the uses are in the successor MBB being
        // sunken into and they are all PHI nodes. In this case, machine-sink must
        // break the critical edge first.
        bool Status = PostponeSplitCriticalEdge(MI, ParentBlock,
                                                SuccToSinkTo, BreakPHIEdge);
        if (!Status)
            DEBUG(dbgs() << " *** PUNTING: Not legal or profitable to "
                  "break critical edge\n");
        // The instruction will not be sunk this time.
        return false;
    }

    // Determine where to insert into. Skip phi nodes.
    MachineBasicBlock::iterator InsertPos = SuccToSinkTo->begin();
    while (InsertPos != SuccToSinkTo->end() && InsertPos->isPHI())
        ++InsertPos;

    // collect matching debug values.
    SmallVector<MachineInstr *, 2> DbgValuesToSink;
    collectDebugValues(MI, DbgValuesToSink);

    // Move the instruction.
    SuccToSinkTo->splice(InsertPos, ParentBlock, MI,
                         ++MachineBasicBlock::iterator(MI));

    // Move debug values.
    for (SmallVectorImpl<MachineInstr *>::iterator DBI = DbgValuesToSink.begin(),
            DBE = DbgValuesToSink.end(); DBI != DBE; ++DBI) {
        MachineInstr *DbgMI = *DBI;
        SuccToSinkTo->splice(InsertPos, ParentBlock,  DbgMI,
                             ++MachineBasicBlock::iterator(DbgMI));
    }

    // Conservatively, clear any kill flags, since it's possible that they are no
    // longer correct.
    MI->clearKillInfo();

    return true;
}
/// findMatchingInsn - Scan the instructions looking for a load/store that can
/// be combined with the current instruction into a load/store pair.
MachineBasicBlock::iterator
AArch64LoadStoreOpt::findMatchingInsn(MachineBasicBlock::iterator I,
                                      LdStPairFlags &Flags, unsigned Limit) {
  MachineBasicBlock::iterator E = I->getParent()->end();
  MachineBasicBlock::iterator MBBI = I;
  MachineInstr *FirstMI = I;
  ++MBBI;

  unsigned Opc = FirstMI->getOpcode();
  bool MayLoad = FirstMI->mayLoad();
  bool IsUnscaled = isUnscaledLdSt(FirstMI);
  unsigned Reg = getLdStRegOp(FirstMI).getReg();
  unsigned BaseReg = getLdStBaseOp(FirstMI).getReg();
  int Offset = getLdStOffsetOp(FirstMI).getImm();

  // Early exit if the first instruction modifies the base register.
  // e.g., ldr x0, [x0]
  if (FirstMI->modifiesRegister(BaseReg, TRI))
    return E;

  // Early exit if the offset if not possible to match. (6 bits of positive
  // range, plus allow an extra one in case we find a later insn that matches
  // with Offset-1)
  int OffsetStride = IsUnscaled ? getMemScale(FirstMI) : 1;
  if (!isSmallTypeLdMerge(Opc) &&
      !inBoundsForPair(IsUnscaled, Offset, OffsetStride))
    return E;

  // Track which registers have been modified and used between the first insn
  // (inclusive) and the second insn.
  BitVector ModifiedRegs, UsedRegs;
  ModifiedRegs.resize(TRI->getNumRegs());
  UsedRegs.resize(TRI->getNumRegs());

  // Remember any instructions that read/write memory between FirstMI and MI.
  SmallVector<MachineInstr *, 4> MemInsns;

  for (unsigned Count = 0; MBBI != E && Count < Limit; ++MBBI) {
    MachineInstr *MI = MBBI;
    // Skip DBG_VALUE instructions. Otherwise debug info can affect the
    // optimization by changing how far we scan.
    if (MI->isDebugValue())
      continue;

    // Now that we know this is a real instruction, count it.
    ++Count;

    bool CanMergeOpc = Opc == MI->getOpcode();
    Flags.setSExtIdx(-1);
    if (!CanMergeOpc) {
      bool IsValidLdStrOpc;
      unsigned NonSExtOpc = getMatchingNonSExtOpcode(Opc, &IsValidLdStrOpc);
      assert(IsValidLdStrOpc &&
             "Given Opc should be a Load or Store with an immediate");
      // Opc will be the first instruction in the pair.
      Flags.setSExtIdx(NonSExtOpc == (unsigned)Opc ? 1 : 0);
      CanMergeOpc = NonSExtOpc == getMatchingNonSExtOpcode(MI->getOpcode());
    }

    if (CanMergeOpc && getLdStOffsetOp(MI).isImm()) {
      assert(MI->mayLoadOrStore() && "Expected memory operation.");
      // If we've found another instruction with the same opcode, check to see
      // if the base and offset are compatible with our starting instruction.
      // These instructions all have scaled immediate operands, so we just
      // check for +1/-1. Make sure to check the new instruction offset is
      // actually an immediate and not a symbolic reference destined for
      // a relocation.
      //
      // Pairwise instructions have a 7-bit signed offset field. Single insns
      // have a 12-bit unsigned offset field. To be a valid combine, the
      // final offset must be in range.
      unsigned MIBaseReg = getLdStBaseOp(MI).getReg();
      int MIOffset = getLdStOffsetOp(MI).getImm();
      if (BaseReg == MIBaseReg && ((Offset == MIOffset + OffsetStride) ||
                                   (Offset + OffsetStride == MIOffset))) {
        int MinOffset = Offset < MIOffset ? Offset : MIOffset;
        // If this is a volatile load/store that otherwise matched, stop looking
        // as something is going on that we don't have enough information to
        // safely transform. Similarly, stop if we see a hint to avoid pairs.
        if (MI->hasOrderedMemoryRef() || TII->isLdStPairSuppressed(MI))
          return E;
        // If the resultant immediate offset of merging these instructions
        // is out of range for a pairwise instruction, bail and keep looking.
        bool MIIsUnscaled = isUnscaledLdSt(MI);
        bool IsSmallTypeLd = isSmallTypeLdMerge(MI->getOpcode());
        if (!IsSmallTypeLd &&
            !inBoundsForPair(MIIsUnscaled, MinOffset, OffsetStride)) {
          trackRegDefsUses(MI, ModifiedRegs, UsedRegs, TRI);
          MemInsns.push_back(MI);
          continue;
        }

        if (IsSmallTypeLd) {
          // If the alignment requirements of the larger type scaled load
          // instruction can't express the scaled offset of the smaller type
          // input, bail and keep looking.
          if (!IsUnscaled && alignTo(MinOffset, 2) != MinOffset) {
            trackRegDefsUses(MI, ModifiedRegs, UsedRegs, TRI);
            MemInsns.push_back(MI);
            continue;
          }
        } else {
          // If the alignment requirements of the paired (scaled) instruction
          // can't express the offset of the unscaled input, bail and keep
          // looking.
          if (IsUnscaled && (alignTo(MinOffset, OffsetStride) != MinOffset)) {
            trackRegDefsUses(MI, ModifiedRegs, UsedRegs, TRI);
            MemInsns.push_back(MI);
            continue;
          }
        }
        // If the destination register of the loads is the same register, bail
        // and keep looking. A load-pair instruction with both destination
        // registers the same is UNPREDICTABLE and will result in an exception.
        if (MayLoad && Reg == getLdStRegOp(MI).getReg()) {
          trackRegDefsUses(MI, ModifiedRegs, UsedRegs, TRI);
          MemInsns.push_back(MI);
          continue;
        }

        // If the Rt of the second instruction was not modified or used between
        // the two instructions and none of the instructions between the second
        // and first alias with the second, we can combine the second into the
        // first.
        if (!ModifiedRegs[getLdStRegOp(MI).getReg()] &&
            !(MI->mayLoad() && UsedRegs[getLdStRegOp(MI).getReg()]) &&
            !mayAlias(MI, MemInsns, TII)) {
          Flags.setMergeForward(false);
          return MBBI;
        }

        // Likewise, if the Rt of the first instruction is not modified or used
        // between the two instructions and none of the instructions between the
        // first and the second alias with the first, we can combine the first
        // into the second.
        if (!ModifiedRegs[getLdStRegOp(FirstMI).getReg()] &&
            !(MayLoad && UsedRegs[getLdStRegOp(FirstMI).getReg()]) &&
            !mayAlias(FirstMI, MemInsns, TII)) {
          Flags.setMergeForward(true);
          return MBBI;
        }
        // Unable to combine these instructions due to interference in between.
        // Keep looking.
      }
    }

    // If the instruction wasn't a matching load or store.  Stop searching if we
    // encounter a call instruction that might modify memory.
    if (MI->isCall())
      return E;

    // Update modified / uses register lists.
    trackRegDefsUses(MI, ModifiedRegs, UsedRegs, TRI);

    // Otherwise, if the base register is modified, we have no match, so
    // return early.
    if (ModifiedRegs[BaseReg])
      return E;

    // Update list of instructions that read/write memory.
    if (MI->mayLoadOrStore())
      MemInsns.push_back(MI);
  }
  return E;
}
void MipsSEInstrInfo::expandPseudoMFHiLo(MachineBasicBlock &MBB,
                                         MachineBasicBlock::iterator I,
                                         unsigned NewOpc) const {
  BuildMI(MBB, I, I->getDebugLoc(), get(NewOpc), I->getOperand(0).getReg());
}
MachineBasicBlock::iterator
AArch64LoadStoreOpt::mergeUpdateInsn(MachineBasicBlock::iterator I,
                                     MachineBasicBlock::iterator Update,
                                     bool IsPreIdx) {
  assert((Update->getOpcode() == AArch64::ADDXri ||
          Update->getOpcode() == AArch64::SUBXri) &&
         "Unexpected base register update instruction to merge!");
  MachineBasicBlock::iterator NextI = I;
  // Return the instruction following the merged instruction, which is
  // the instruction following our unmerged load. Unless that's the add/sub
  // instruction we're merging, in which case it's the one after that.
  if (++NextI == Update)
    ++NextI;

  int Value = Update->getOperand(2).getImm();
  assert(AArch64_AM::getShiftValue(Update->getOperand(3).getImm()) == 0 &&
         "Can't merge 1 << 12 offset into pre-/post-indexed load / store");
  if (Update->getOpcode() == AArch64::SUBXri)
    Value = -Value;

  unsigned NewOpc = IsPreIdx ? getPreIndexedOpcode(I->getOpcode())
                             : getPostIndexedOpcode(I->getOpcode());
  MachineInstrBuilder MIB;
  if (!isPairedLdSt(I)) {
    // Non-paired instruction.
    MIB = BuildMI(*I->getParent(), I, I->getDebugLoc(), TII->get(NewOpc))
              .addOperand(getLdStRegOp(Update))
              .addOperand(getLdStRegOp(I))
              .addOperand(getLdStBaseOp(I))
              .addImm(Value);
  } else {
    // Paired instruction.
    int Scale = getMemScale(I);
    MIB = BuildMI(*I->getParent(), I, I->getDebugLoc(), TII->get(NewOpc))
              .addOperand(getLdStRegOp(Update))
              .addOperand(getLdStRegOp(I, 0))
              .addOperand(getLdStRegOp(I, 1))
              .addOperand(getLdStBaseOp(I))
              .addImm(Value / Scale);
  }
  (void)MIB;

  if (IsPreIdx)
    DEBUG(dbgs() << "Creating pre-indexed load/store.");
  else
    DEBUG(dbgs() << "Creating post-indexed load/store.");
  DEBUG(dbgs() << "    Replacing instructions:\n    ");
  DEBUG(I->print(dbgs()));
  DEBUG(dbgs() << "    ");
  DEBUG(Update->print(dbgs()));
  DEBUG(dbgs() << "  with instruction:\n    ");
  DEBUG(((MachineInstr *)MIB)->print(dbgs()));
  DEBUG(dbgs() << "\n");

  // Erase the old instructions for the block.
  I->eraseFromParent();
  Update->eraseFromParent();

  return NextI;
}
bool Thumb2ITBlockPass::InsertITInstructions(MachineBasicBlock &MBB) {
  bool Modified = false;

  SmallSet<unsigned, 4> Defs;
  SmallSet<unsigned, 4> Uses;
  MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end();
  while (MBBI != E) {
    MachineInstr *MI = &*MBBI;
    DebugLoc dl = MI->getDebugLoc();
    unsigned PredReg = 0;
    ARMCC::CondCodes CC = getITInstrPredicate(*MI, PredReg);
    if (CC == ARMCC::AL) {
      ++MBBI;
      continue;
    }

    Defs.clear();
    Uses.clear();
    TrackDefUses(MI, Defs, Uses, TRI);

    // Insert an IT instruction.
    MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII->get(ARM::t2IT))
      .addImm(CC);

    // Add implicit use of ITSTATE to IT block instructions.
    MI->addOperand(MachineOperand::CreateReg(ARM::ITSTATE, false/*ifDef*/,
                                             true/*isImp*/, false/*isKill*/));

    MachineInstr *LastITMI = MI;
    MachineBasicBlock::iterator InsertPos = MIB.getInstr();
    ++MBBI;

    // Form IT block.
    ARMCC::CondCodes OCC = ARMCC::getOppositeCondition(CC);
    unsigned Mask = 0, Pos = 3;

    // v8 IT blocks are limited to one conditional op unless -arm-no-restrict-it
    // is set: skip the loop
    if (!restrictIT) {
      // Branches, including tricky ones like LDM_RET, need to end an IT
      // block so check the instruction we just put in the block.
      for (; MBBI != E && Pos &&
             (!MI->isBranch() && !MI->isReturn()) ; ++MBBI) {
        if (MBBI->isDebugValue())
          continue;

        MachineInstr *NMI = &*MBBI;
        MI = NMI;

        unsigned NPredReg = 0;
        ARMCC::CondCodes NCC = getITInstrPredicate(*NMI, NPredReg);
        if (NCC == CC || NCC == OCC) {
          Mask |= (NCC & 1) << Pos;
          // Add implicit use of ITSTATE.
          NMI->addOperand(MachineOperand::CreateReg(ARM::ITSTATE, false/*ifDef*/,
                                                 true/*isImp*/, false/*isKill*/));
          LastITMI = NMI;
        } else {
          if (NCC == ARMCC::AL &&
              MoveCopyOutOfITBlock(NMI, CC, OCC, Defs, Uses)) {
            --MBBI;
            MBB.remove(NMI);
            MBB.insert(InsertPos, NMI);
            ClearKillFlags(MI, Uses);
            ++NumMovedInsts;
            continue;
          }
          break;
        }
        TrackDefUses(NMI, Defs, Uses, TRI);
        --Pos;
      }
    }

    // Finalize IT mask.
    Mask |= (1 << Pos);
    // Tag along (firstcond[0] << 4) with the mask.
    Mask |= (CC & 1) << 4;
    MIB.addImm(Mask);

    // Last instruction in IT block kills ITSTATE.
    LastITMI->findRegisterUseOperand(ARM::ITSTATE)->setIsKill();

    // Finalize the bundle.
    finalizeBundle(MBB, InsertPos.getInstrIterator(),
                   ++LastITMI->getIterator());

    Modified = true;
    ++NumITs;
  }

  return Modified;
}
Beispiel #30
0
bool SILoadStoreOptimizer::findMatchingInst(CombineInfo &CI) {
  MachineBasicBlock *MBB = CI.I->getParent();
  MachineBasicBlock::iterator E = MBB->end();
  MachineBasicBlock::iterator MBBI = CI.I;

  const unsigned Opc = CI.I->getOpcode();
  const InstClassEnum InstClass = getInstClass(Opc);

  if (InstClass == UNKNOWN) {
    return false;
  }

  const unsigned Regs = getRegs(Opc);

  unsigned AddrOpName[5] = {0};
  int AddrIdx[5];
  const MachineOperand *AddrReg[5];
  unsigned NumAddresses = 0;

  if (Regs & ADDR) {
    AddrOpName[NumAddresses++] = AMDGPU::OpName::addr;
  }

  if (Regs & SBASE) {
    AddrOpName[NumAddresses++] = AMDGPU::OpName::sbase;
  }

  if (Regs & SRSRC) {
    AddrOpName[NumAddresses++] = AMDGPU::OpName::srsrc;
  }

  if (Regs & SOFFSET) {
    AddrOpName[NumAddresses++] = AMDGPU::OpName::soffset;
  }

  if (Regs & VADDR) {
    AddrOpName[NumAddresses++] = AMDGPU::OpName::vaddr;
  }

  for (unsigned i = 0; i < NumAddresses; i++) {
    AddrIdx[i] = AMDGPU::getNamedOperandIdx(CI.I->getOpcode(), AddrOpName[i]);
    AddrReg[i] = &CI.I->getOperand(AddrIdx[i]);

    // We only ever merge operations with the same base address register, so
    // don't bother scanning forward if there are no other uses.
    if (AddrReg[i]->isReg() &&
        (TargetRegisterInfo::isPhysicalRegister(AddrReg[i]->getReg()) ||
         MRI->hasOneNonDBGUse(AddrReg[i]->getReg())))
      return false;
  }

  ++MBBI;

  DenseSet<unsigned> RegDefsToMove;
  DenseSet<unsigned> PhysRegUsesToMove;
  addDefsUsesToList(*CI.I, RegDefsToMove, PhysRegUsesToMove);

  for (; MBBI != E; ++MBBI) {
    const bool IsDS = (InstClass == DS_READ) || (InstClass == DS_WRITE);

    if ((getInstClass(MBBI->getOpcode()) != InstClass) ||
        (IsDS && (MBBI->getOpcode() != Opc))) {
      // This is not a matching DS instruction, but we can keep looking as
      // long as one of these conditions are met:
      // 1. It is safe to move I down past MBBI.
      // 2. It is safe to move MBBI down past the instruction that I will
      //    be merged into.

      if (MBBI->hasUnmodeledSideEffects()) {
        // We can't re-order this instruction with respect to other memory
        // operations, so we fail both conditions mentioned above.
        return false;
      }

      if (MBBI->mayLoadOrStore() &&
          (!memAccessesCanBeReordered(*CI.I, *MBBI, AA) ||
           !canMoveInstsAcrossMemOp(*MBBI, CI.InstsToMove, AA))) {
        // We fail condition #1, but we may still be able to satisfy condition
        // #2.  Add this instruction to the move list and then we will check
        // if condition #2 holds once we have selected the matching instruction.
        CI.InstsToMove.push_back(&*MBBI);
        addDefsUsesToList(*MBBI, RegDefsToMove, PhysRegUsesToMove);
        continue;
      }

      // When we match I with another DS instruction we will be moving I down
      // to the location of the matched instruction any uses of I will need to
      // be moved down as well.
      addToListsIfDependent(*MBBI, RegDefsToMove, PhysRegUsesToMove,
                            CI.InstsToMove);
      continue;
    }

    // Don't merge volatiles.
    if (MBBI->hasOrderedMemoryRef())
      return false;

    // Handle a case like
    //   DS_WRITE_B32 addr, v, idx0
    //   w = DS_READ_B32 addr, idx0
    //   DS_WRITE_B32 addr, f(w), idx1
    // where the DS_READ_B32 ends up in InstsToMove and therefore prevents
    // merging of the two writes.
    if (addToListsIfDependent(*MBBI, RegDefsToMove, PhysRegUsesToMove,
                              CI.InstsToMove))
      continue;

    bool Match = true;
    for (unsigned i = 0; i < NumAddresses; i++) {
      const MachineOperand &AddrRegNext = MBBI->getOperand(AddrIdx[i]);

      if (AddrReg[i]->isImm() || AddrRegNext.isImm()) {
        if (AddrReg[i]->isImm() != AddrRegNext.isImm() ||
            AddrReg[i]->getImm() != AddrRegNext.getImm()) {
          Match = false;
          break;
        }
        continue;
      }

      // Check same base pointer. Be careful of subregisters, which can occur
      // with vectors of pointers.
      if (AddrReg[i]->getReg() != AddrRegNext.getReg() ||
          AddrReg[i]->getSubReg() != AddrRegNext.getSubReg()) {
        Match = false;
        break;
      }
    }

    if (Match) {
      int OffsetIdx =
          AMDGPU::getNamedOperandIdx(CI.I->getOpcode(), AMDGPU::OpName::offset);
      CI.Offset0 = CI.I->getOperand(OffsetIdx).getImm();
      CI.Width0 = getOpcodeWidth(*CI.I);
      CI.Offset1 = MBBI->getOperand(OffsetIdx).getImm();
      CI.Width1 = getOpcodeWidth(*MBBI);
      CI.Paired = MBBI;

      if ((CI.InstClass == DS_READ) || (CI.InstClass == DS_WRITE)) {
        CI.Offset0 &= 0xffff;
        CI.Offset1 &= 0xffff;
      } else {
        CI.GLC0 = TII->getNamedOperand(*CI.I, AMDGPU::OpName::glc)->getImm();
        CI.GLC1 = TII->getNamedOperand(*MBBI, AMDGPU::OpName::glc)->getImm();
        if (CI.InstClass != S_BUFFER_LOAD_IMM) {
          CI.SLC0 = TII->getNamedOperand(*CI.I, AMDGPU::OpName::slc)->getImm();
          CI.SLC1 = TII->getNamedOperand(*MBBI, AMDGPU::OpName::slc)->getImm();
        }
      }

      // Check both offsets fit in the reduced range.
      // We also need to go through the list of instructions that we plan to
      // move and make sure they are all safe to move down past the merged
      // instruction.
      if (widthsFit(*STM, CI) && offsetsCanBeCombined(CI))
        if (canMoveInstsAcrossMemOp(*MBBI, CI.InstsToMove, AA))
          return true;
    }

    // We've found a load/store that we couldn't merge for some reason.
    // We could potentially keep looking, but we'd need to make sure that
    // it was safe to move I and also all the instruction in InstsToMove
    // down past this instruction.
    // check if we can move I across MBBI and if we can move all I's users
    if (!memAccessesCanBeReordered(*CI.I, *MBBI, AA) ||
        !canMoveInstsAcrossMemOp(*MBBI, CI.InstsToMove, AA))
      break;
  }
  return false;
}