lib/Target/Alpha/AlphaInstrInfo.cpp

//===- AlphaInstrInfo.cpp - Alpha Instruction Information -------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the Alpha implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//

#include "Alpha.h"
#include "AlphaInstrInfo.h"
#include "AlphaGenInstrInfo.inc"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include <iostream>
using namespace llvm;

AlphaInstrInfo::AlphaInstrInfo()
  : TargetInstrInfo(AlphaInsts, sizeof(AlphaInsts)/sizeof(AlphaInsts[0])) { }


bool AlphaInstrInfo::isMoveInstr(const MachineInstr& MI,
                                 unsigned& sourceReg,
                                 unsigned& destReg) const {
  MachineOpCode oc = MI.getOpcode();
  if (oc == Alpha::BIS    || 
      oc == Alpha::CPYSS  || 
      oc == Alpha::CPYST  ||
      oc == Alpha::CPYSSt || 
      oc == Alpha::CPYSTs) {
    // or r1, r2, r2 
    // cpys(s|t) r1 r2 r2
    assert(MI.getNumOperands() == 3 &&
           MI.getOperand(0).isRegister() &&
           MI.getOperand(1).isRegister() &&
           MI.getOperand(2).isRegister() &&
           "invalid Alpha BIS instruction!");
    if (MI.getOperand(1).getReg() == MI.getOperand(2).getReg()) {
      sourceReg = MI.getOperand(1).getReg();
      destReg = MI.getOperand(0).getReg();
      return true;
    }
  }
  return false;
}

unsigned 
AlphaInstrInfo::isLoadFromStackSlot(MachineInstr *MI, int &FrameIndex) const {
  switch (MI->getOpcode()) {
  case Alpha::LDL:
  case Alpha::LDQ:
  case Alpha::LDBU:
  case Alpha::LDWU:
  case Alpha::LDS:
  case Alpha::LDT:
    if (MI->getOperand(1).isFrameIndex()) {
      FrameIndex = MI->getOperand(1).getFrameIndex();
      return MI->getOperand(0).getReg();
    }
    break;
  }
  return 0;
}

unsigned 
AlphaInstrInfo::isStoreToStackSlot(MachineInstr *MI, int &FrameIndex) const {
  switch (MI->getOpcode()) {
  case Alpha::STL:
  case Alpha::STQ:
  case Alpha::STB:
  case Alpha::STW:
  case Alpha::STS:
  case Alpha::STT:
    if (MI->getOperand(1).isFrameIndex()) {
      FrameIndex = MI->getOperand(1).getFrameIndex();
      return MI->getOperand(0).getReg();
    }
    break;
  }
  return 0;
}

void AlphaInstrInfo::InsertBranch(MachineBasicBlock &MBB,MachineBasicBlock *TBB,
                                  MachineBasicBlock *FBB,
                                  const std::vector<MachineOperand> &Cond)const{
  // Can only insert uncond branches so far.
  assert(Cond.empty() && !FBB && TBB && "Can only handle uncond branches!");
  BuildMI(&MBB, Alpha::BR, 1).addMBB(TBB);
}