//===-- SIInstrInfo.cpp - SI Instruction Information  ---------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file
/// \brief SI Implementation of TargetInstrInfo.
//
//===----------------------------------------------------------------------===//


#include "SIInstrInfo.h"
#include "AMDGPUTargetMachine.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/MC/MCInstrDesc.h"
#include <stdio.h>

using namespace llvm;

SIInstrInfo::SIInstrInfo(AMDGPUTargetMachine &tm)
  : AMDGPUInstrInfo(tm),
    RI(tm, *this)
    { }

const SIRegisterInfo &SIInstrInfo::getRegisterInfo() const {
  return RI;
}

void
SIInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
                         MachineBasicBlock::iterator MI, DebugLoc DL,
                         unsigned DestReg, unsigned SrcReg,
                         bool KillSrc) const {

  // If we are trying to copy to or from SCC, there is a bug somewhere else in
  // the backend.  While it may be theoretically possible to do this, it should
  // never be necessary.
  assert(DestReg != AMDGPU::SCC && SrcReg != AMDGPU::SCC);

  const int16_t Sub0_15[] = {
    AMDGPU::sub0, AMDGPU::sub1, AMDGPU::sub2, AMDGPU::sub3,
    AMDGPU::sub4, AMDGPU::sub5, AMDGPU::sub6, AMDGPU::sub7,
    AMDGPU::sub8, AMDGPU::sub9, AMDGPU::sub10, AMDGPU::sub11,
    AMDGPU::sub12, AMDGPU::sub13, AMDGPU::sub14, AMDGPU::sub15, 0
  };

  const int16_t Sub0_7[] = {
    AMDGPU::sub0, AMDGPU::sub1, AMDGPU::sub2, AMDGPU::sub3,
    AMDGPU::sub4, AMDGPU::sub5, AMDGPU::sub6, AMDGPU::sub7, 0
  };

  const int16_t Sub0_3[] = {
    AMDGPU::sub0, AMDGPU::sub1, AMDGPU::sub2, AMDGPU::sub3, 0
  };

  const int16_t Sub0_2[] = {
    AMDGPU::sub0, AMDGPU::sub1, AMDGPU::sub2, 0
  };

  const int16_t Sub0_1[] = {
    AMDGPU::sub0, AMDGPU::sub1, 0
  };

  unsigned Opcode;
  const int16_t *SubIndices;

  if (AMDGPU::M0 == DestReg) {
    // Check if M0 isn't already set to this value
    for (MachineBasicBlock::reverse_iterator E = MBB.rend(),
      I = MachineBasicBlock::reverse_iterator(MI); I != E; ++I) {

      if (!I->definesRegister(AMDGPU::M0))
        continue;

      unsigned Opc = I->getOpcode();
      if (Opc != TargetOpcode::COPY && Opc != AMDGPU::S_MOV_B32)
        break;

      if (!I->readsRegister(SrcReg))
        break;

      // The copy isn't necessary
      return;
    }
  }

  if (AMDGPU::SReg_32RegClass.contains(DestReg)) {
    assert(AMDGPU::SReg_32RegClass.contains(SrcReg));
    BuildMI(MBB, MI, DL, get(AMDGPU::S_MOV_B32), DestReg)
            .addReg(SrcReg, getKillRegState(KillSrc));
    return;

  } else if (AMDGPU::SReg_64RegClass.contains(DestReg)) {
    assert(AMDGPU::SReg_64RegClass.contains(SrcReg));
    BuildMI(MBB, MI, DL, get(AMDGPU::S_MOV_B64), DestReg)
            .addReg(SrcReg, getKillRegState(KillSrc));
    return;

  } else if (AMDGPU::SReg_128RegClass.contains(DestReg)) {
    assert(AMDGPU::SReg_128RegClass.contains(SrcReg));
    Opcode = AMDGPU::S_MOV_B32;
    SubIndices = Sub0_3;

  } else if (AMDGPU::SReg_256RegClass.contains(DestReg)) {
    assert(AMDGPU::SReg_256RegClass.contains(SrcReg));
    Opcode = AMDGPU::S_MOV_B32;
    SubIndices = Sub0_7;

  } else if (AMDGPU::SReg_512RegClass.contains(DestReg)) {
    assert(AMDGPU::SReg_512RegClass.contains(SrcReg));
    Opcode = AMDGPU::S_MOV_B32;
    SubIndices = Sub0_15;

  } else if (AMDGPU::VReg_32RegClass.contains(DestReg)) {
    assert(AMDGPU::VReg_32RegClass.contains(SrcReg) ||
	   AMDGPU::SReg_32RegClass.contains(SrcReg));
    BuildMI(MBB, MI, DL, get(AMDGPU::V_MOV_B32_e32), DestReg)
            .addReg(SrcReg, getKillRegState(KillSrc));
    return;

  } else if (AMDGPU::VReg_64RegClass.contains(DestReg)) {
    assert(AMDGPU::VReg_64RegClass.contains(SrcReg) ||
	   AMDGPU::SReg_64RegClass.contains(SrcReg));
    Opcode = AMDGPU::V_MOV_B32_e32;
    SubIndices = Sub0_1;

  } else if (AMDGPU::VReg_96RegClass.contains(DestReg)) {
    assert(AMDGPU::VReg_96RegClass.contains(SrcReg));
    Opcode = AMDGPU::V_MOV_B32_e32;
    SubIndices = Sub0_2;

  } else if (AMDGPU::VReg_128RegClass.contains(DestReg)) {
    assert(AMDGPU::VReg_128RegClass.contains(SrcReg) ||
	   AMDGPU::SReg_128RegClass.contains(SrcReg));
    Opcode = AMDGPU::V_MOV_B32_e32;
    SubIndices = Sub0_3;

  } else if (AMDGPU::VReg_256RegClass.contains(DestReg)) {
    assert(AMDGPU::VReg_256RegClass.contains(SrcReg) ||
	   AMDGPU::SReg_256RegClass.contains(SrcReg));
    Opcode = AMDGPU::V_MOV_B32_e32;
    SubIndices = Sub0_7;

  } else if (AMDGPU::VReg_512RegClass.contains(DestReg)) {
    assert(AMDGPU::VReg_512RegClass.contains(SrcReg) ||
	   AMDGPU::SReg_512RegClass.contains(SrcReg));
    Opcode = AMDGPU::V_MOV_B32_e32;
    SubIndices = Sub0_15;

  } else {
    llvm_unreachable("Can't copy register!");
  }

  while (unsigned SubIdx = *SubIndices++) {
    MachineInstrBuilder Builder = BuildMI(MBB, MI, DL,
      get(Opcode), RI.getSubReg(DestReg, SubIdx));

    Builder.addReg(RI.getSubReg(SrcReg, SubIdx), getKillRegState(KillSrc));

    if (*SubIndices)
      Builder.addReg(DestReg, RegState::Define | RegState::Implicit);
  }
}

unsigned SIInstrInfo::commuteOpcode(unsigned Opcode) const {

  int NewOpc;

  // Try to map original to commuted opcode
  if ((NewOpc = AMDGPU::getCommuteRev(Opcode)) != -1)
    return NewOpc;

  // Try to map commuted to original opcode
  if ((NewOpc = AMDGPU::getCommuteOrig(Opcode)) != -1)
    return NewOpc;

  return Opcode;
}

MachineInstr *SIInstrInfo::commuteInstruction(MachineInstr *MI,
                                              bool NewMI) const {

  if (MI->getNumOperands() < 3 || !MI->getOperand(1).isReg() ||
      !MI->getOperand(2).isReg())
    return 0;

  MI = TargetInstrInfo::commuteInstruction(MI, NewMI);

  if (MI)
    MI->setDesc(get(commuteOpcode(MI->getOpcode())));

  return MI;
}

MachineInstr * SIInstrInfo::getMovImmInstr(MachineFunction *MF, unsigned DstReg,
                                           int64_t Imm) const {
  MachineInstr * MI = MF->CreateMachineInstr(get(AMDGPU::V_MOV_B32_e32), DebugLoc());
  MachineInstrBuilder MIB(*MF, MI);
  MIB.addReg(DstReg, RegState::Define);
  MIB.addImm(Imm);

  return MI;

}

bool SIInstrInfo::isMov(unsigned Opcode) const {
  switch(Opcode) {
  default: return false;
  case AMDGPU::S_MOV_B32:
  case AMDGPU::S_MOV_B64:
  case AMDGPU::V_MOV_B32_e32:
  case AMDGPU::V_MOV_B32_e64:
    return true;
  }
}

bool
SIInstrInfo::isSafeToMoveRegClassDefs(const TargetRegisterClass *RC) const {
  return RC != &AMDGPU::EXECRegRegClass;
}

//===----------------------------------------------------------------------===//
// Indirect addressing callbacks
//===----------------------------------------------------------------------===//

unsigned SIInstrInfo::calculateIndirectAddress(unsigned RegIndex,
                                                 unsigned Channel) const {
  assert(Channel == 0);
  return RegIndex;
}


int SIInstrInfo::getIndirectIndexBegin(const MachineFunction &MF) const {
  llvm_unreachable("Unimplemented");
}

int SIInstrInfo::getIndirectIndexEnd(const MachineFunction &MF) const {
  llvm_unreachable("Unimplemented");
}

const TargetRegisterClass *SIInstrInfo::getIndirectAddrStoreRegClass(
                                                     unsigned SourceReg) const {
  llvm_unreachable("Unimplemented");
}

const TargetRegisterClass *SIInstrInfo::getIndirectAddrLoadRegClass() const {
  llvm_unreachable("Unimplemented");
}

MachineInstrBuilder SIInstrInfo::buildIndirectWrite(
                                   MachineBasicBlock *MBB,
                                   MachineBasicBlock::iterator I,
                                   unsigned ValueReg,
                                   unsigned Address, unsigned OffsetReg) const {
  llvm_unreachable("Unimplemented");
}

MachineInstrBuilder SIInstrInfo::buildIndirectRead(
                                   MachineBasicBlock *MBB,
                                   MachineBasicBlock::iterator I,
                                   unsigned ValueReg,
                                   unsigned Address, unsigned OffsetReg) const {
  llvm_unreachable("Unimplemented");
}

const TargetRegisterClass *SIInstrInfo::getSuperIndirectRegClass() const {
  llvm_unreachable("Unimplemented");
}