unsigned SIRegisterInfo::getNumReservedSGPRs(const SISubtarget &ST,
                                             const SIMachineFunctionInfo &MFI) const {
  if (MFI.hasFlatScratchInit()) {
    if (ST.getGeneration() >= AMDGPUSubtarget::VOLCANIC_ISLANDS)
      return 6; // FLAT_SCRATCH, XNACK, VCC (in that order)

    if (ST.getGeneration() == AMDGPUSubtarget::SEA_ISLANDS)
      return 4; // FLAT_SCRATCH, VCC (in that order)
  }

  if (ST.isXNACKEnabled())
    return 4; // XNACK, VCC (in that order)

  return 2; // VCC.
}

bool GCNRegPressure::less(const SISubtarget &ST,
                          const GCNRegPressure& O,
                          unsigned MaxOccupancy) const {
  const auto SGPROcc = std::min(MaxOccupancy,
                                ST.getOccupancyWithNumSGPRs(getSGPRNum()));
  const auto VGPROcc = std::min(MaxOccupancy,
                                ST.getOccupancyWithNumVGPRs(getVGPRNum()));
  const auto OtherSGPROcc = std::min(MaxOccupancy,
                                ST.getOccupancyWithNumSGPRs(O.getSGPRNum()));
  const auto OtherVGPROcc = std::min(MaxOccupancy,
                                ST.getOccupancyWithNumVGPRs(O.getVGPRNum()));

  const auto Occ = std::min(SGPROcc, VGPROcc);
  const auto OtherOcc = std::min(OtherSGPROcc, OtherVGPROcc);
  if (Occ != OtherOcc)
    return Occ > OtherOcc;

  bool SGPRImportant = SGPROcc < VGPROcc;
  const bool OtherSGPRImportant = OtherSGPROcc < OtherVGPROcc;

  // if both pressures disagree on what is more important compare vgprs
  if (SGPRImportant != OtherSGPRImportant) {
    SGPRImportant = false;
  }

  // compare large regs pressure
  bool SGPRFirst = SGPRImportant;
  for (int I = 2; I > 0; --I, SGPRFirst = !SGPRFirst) {
    if (SGPRFirst) {
      auto SW = getSGPRTuplesWeight();
      auto OtherSW = O.getSGPRTuplesWeight();
      if (SW != OtherSW)
        return SW < OtherSW;
    } else {
      auto VW = getVGPRTuplesWeight();
      auto OtherVW = O.getVGPRTuplesWeight();
      if (VW != OtherVW)
        return VW < OtherVW;
    }
  }
  return SGPRImportant ? (getSGPRNum() < O.getSGPRNum()):
                         (getVGPRNum() < O.getVGPRNum());
}

static unsigned getNumExtraSGPRs(const SISubtarget &ST,
                                 bool VCCUsed,
                                 bool FlatScrUsed) {
  unsigned ExtraSGPRs = 0;
  if (VCCUsed)
    ExtraSGPRs = 2;

  if (ST.getGeneration() < SISubtarget::VOLCANIC_ISLANDS) {
    if (FlatScrUsed)
      ExtraSGPRs = 4;
  } else {
    if (ST.isXNACKEnabled())
      ExtraSGPRs = 4;

    if (FlatScrUsed)
      ExtraSGPRs = 6;
  }

  return ExtraSGPRs;
}

unsigned SIRegisterInfo::getNumSGPRsAllowed(const SISubtarget &ST,
                                            unsigned WaveCount) const {
  if (ST.getGeneration() >= SISubtarget::VOLCANIC_ISLANDS) {
    switch (WaveCount) {
      case 10: return 80;
      case 9:  return 80;
      case 8:  return 96;
      default: return 102;
    }
  } else {
    switch(WaveCount) {
      case 10: return 48;
      case 9:  return 56;
      case 8:  return 64;
      case 7:  return 72;
      case 6:  return 80;
      case 5:  return 96;
      default: return 103;
    }
  }
}

unsigned SIRegisterInfo::getMinNumSGPRs(const SISubtarget &ST,
                                        unsigned WavesPerEU) const {
  if (ST.getGeneration() >= AMDGPUSubtarget::VOLCANIC_ISLANDS) {
    switch (WavesPerEU) {
      case 0:  return 0;
      case 10: return 0;
      case 9:  return 0;
      case 8:  return 81;
      default: return 97;
    }
  } else {
    switch (WavesPerEU) {
      case 0:  return 0;
      case 10: return 0;
      case 9:  return 49;
      case 8:  return 57;
      case 7:  return 65;
      case 6:  return 73;
      case 5:  return 81;
      default: return 97;
    }
  }
}

unsigned SIRegisterInfo::getMaxNumSGPRs(const SISubtarget &ST,
                                        unsigned WavesPerEU) const {
  if (ST.getGeneration() >= AMDGPUSubtarget::VOLCANIC_ISLANDS) {
    switch (WavesPerEU) {
      case 0:  return 80;
      case 10: return 80;
      case 9:  return 80;
      case 8:  return 96;
      default: return getNumAddressableSGPRs(ST);
    }
  } else {
    switch (WavesPerEU) {
      case 0:  return 48;
      case 10: return 48;
      case 9:  return 56;
      case 8:  return 64;
      case 7:  return 72;
      case 6:  return 80;
      case 5:  return 96;
      default: return getNumAddressableSGPRs(ST);
    }
  }
}

unsigned SIRegisterInfo::getNumReservedSGPRs(const SISubtarget &ST) const {
  if (ST.getGeneration() >= AMDGPUSubtarget::VOLCANIC_ISLANDS)
    return 6; // VCC, FLAT_SCRATCH, XNACK.
  return 2; // VCC.
}

unsigned SIRegisterInfo::getNumAddressableSGPRs(const SISubtarget &ST) const {
  if (ST.getGeneration() >= AMDGPUSubtarget::VOLCANIC_ISLANDS)
    return 102;
  return 104;
}

unsigned SIRegisterInfo::getTotalNumSGPRs(const SISubtarget &ST) const {
  if (ST.getGeneration() >= AMDGPUSubtarget::VOLCANIC_ISLANDS)
    return 800;
  return 512;
}

unsigned SIRegisterInfo::getNumDebuggerReservedVGPRs(
  const SISubtarget &ST) const {
  if (ST.debuggerReserveRegs())
    return 4;
  return 0;
}