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	Patch by Sterling Stein! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41758 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
			268 lines
		
	
	
		
			8.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			268 lines
		
	
	
		
			8.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===- AlphaInstrInfo.cpp - Alpha Instruction Information -------*- C++ -*-===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file was developed by the LLVM research group and is distributed under
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| // the University of Illinois Open Source License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| //
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| // This file contains the Alpha implementation of the TargetInstrInfo class.
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #include "Alpha.h"
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| #include "AlphaInstrInfo.h"
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| #include "AlphaGenInstrInfo.inc"
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| #include "llvm/ADT/STLExtras.h"
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| #include "llvm/CodeGen/MachineInstrBuilder.h"
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| using namespace llvm;
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| 
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| AlphaInstrInfo::AlphaInstrInfo()
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|   : TargetInstrInfo(AlphaInsts, array_lengthof(AlphaInsts)),
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|     RI(*this) { }
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| 
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| 
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| bool AlphaInstrInfo::isMoveInstr(const MachineInstr& MI,
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|                                  unsigned& sourceReg,
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|                                  unsigned& destReg) const {
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|   MachineOpCode oc = MI.getOpcode();
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|   if (oc == Alpha::BISr   || 
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|       oc == Alpha::CPYSS  || 
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|       oc == Alpha::CPYST  ||
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|       oc == Alpha::CPYSSt || 
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|       oc == Alpha::CPYSTs) {
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|     // or r1, r2, r2 
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|     // cpys(s|t) r1 r2 r2
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|     assert(MI.getNumOperands() >= 3 &&
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|            MI.getOperand(0).isRegister() &&
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|            MI.getOperand(1).isRegister() &&
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|            MI.getOperand(2).isRegister() &&
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|            "invalid Alpha BIS instruction!");
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|     if (MI.getOperand(1).getReg() == MI.getOperand(2).getReg()) {
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|       sourceReg = MI.getOperand(1).getReg();
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|       destReg = MI.getOperand(0).getReg();
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|       return true;
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|     }
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|   }
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|   return false;
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| }
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| 
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| unsigned 
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| AlphaInstrInfo::isLoadFromStackSlot(MachineInstr *MI, int &FrameIndex) const {
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|   switch (MI->getOpcode()) {
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|   case Alpha::LDL:
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|   case Alpha::LDQ:
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|   case Alpha::LDBU:
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|   case Alpha::LDWU:
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|   case Alpha::LDS:
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|   case Alpha::LDT:
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|     if (MI->getOperand(1).isFrameIndex()) {
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|       FrameIndex = MI->getOperand(1).getFrameIndex();
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|       return MI->getOperand(0).getReg();
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|     }
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|     break;
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|   }
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|   return 0;
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| }
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| 
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| unsigned 
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| AlphaInstrInfo::isStoreToStackSlot(MachineInstr *MI, int &FrameIndex) const {
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|   switch (MI->getOpcode()) {
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|   case Alpha::STL:
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|   case Alpha::STQ:
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|   case Alpha::STB:
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|   case Alpha::STW:
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|   case Alpha::STS:
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|   case Alpha::STT:
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|     if (MI->getOperand(1).isFrameIndex()) {
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|       FrameIndex = MI->getOperand(1).getFrameIndex();
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|       return MI->getOperand(0).getReg();
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|     }
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|     break;
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|   }
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|   return 0;
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| }
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| 
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| static bool isAlphaIntCondCode(unsigned Opcode) {
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|   switch (Opcode) {
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|   case Alpha::BEQ: 
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|   case Alpha::BNE: 
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|   case Alpha::BGE: 
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|   case Alpha::BGT: 
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|   case Alpha::BLE: 
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|   case Alpha::BLT: 
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|   case Alpha::BLBC: 
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|   case Alpha::BLBS:
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|     return true;
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|   default:
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|     return false;
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|   }
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| }
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| 
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| unsigned AlphaInstrInfo::InsertBranch(MachineBasicBlock &MBB,MachineBasicBlock *TBB,
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|                                   MachineBasicBlock *FBB,
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|                                   const std::vector<MachineOperand> &Cond)const{
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|   assert(TBB && "InsertBranch must not be told to insert a fallthrough");
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|   assert((Cond.size() == 2 || Cond.size() == 0) && 
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|          "Alpha branch conditions have two components!");
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| 
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|   // One-way branch.
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|   if (FBB == 0) {
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|     if (Cond.empty())   // Unconditional branch
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|       BuildMI(&MBB, get(Alpha::BR)).addMBB(TBB);
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|     else                // Conditional branch
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|       if (isAlphaIntCondCode(Cond[0].getImm()))
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|         BuildMI(&MBB, get(Alpha::COND_BRANCH_I))
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|           .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB);
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|       else
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|         BuildMI(&MBB, get(Alpha::COND_BRANCH_F))
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|           .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB);
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|     return 1;
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|   }
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|   
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|   // Two-way Conditional Branch.
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|   if (isAlphaIntCondCode(Cond[0].getImm()))
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|     BuildMI(&MBB, get(Alpha::COND_BRANCH_I))
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|       .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB);
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|   else
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|     BuildMI(&MBB, get(Alpha::COND_BRANCH_F))
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|       .addImm(Cond[0].getImm()).addReg(Cond[1].getReg()).addMBB(TBB);
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|   BuildMI(&MBB, get(Alpha::BR)).addMBB(FBB);
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|   return 2;
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| }
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| 
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| static unsigned AlphaRevCondCode(unsigned Opcode) {
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|   switch (Opcode) {
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|   case Alpha::BEQ: return Alpha::BNE;
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|   case Alpha::BNE: return Alpha::BEQ;
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|   case Alpha::BGE: return Alpha::BLT;
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|   case Alpha::BGT: return Alpha::BLE;
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|   case Alpha::BLE: return Alpha::BGT;
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|   case Alpha::BLT: return Alpha::BGE;
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|   case Alpha::BLBC: return Alpha::BLBS;
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|   case Alpha::BLBS: return Alpha::BLBC;
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|   case Alpha::FBEQ: return Alpha::FBNE;
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|   case Alpha::FBNE: return Alpha::FBEQ;
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|   case Alpha::FBGE: return Alpha::FBLT;
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|   case Alpha::FBGT: return Alpha::FBLE;
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|   case Alpha::FBLE: return Alpha::FBGT;
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|   case Alpha::FBLT: return Alpha::FBGE;
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|   default:
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|     assert(0 && "Unknown opcode");
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|   }
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| }
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| 
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| // Branch analysis.
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| bool AlphaInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB,
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|                                  MachineBasicBlock *&FBB,
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|                                  std::vector<MachineOperand> &Cond) const {
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|   // If the block has no terminators, it just falls into the block after it.
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|   MachineBasicBlock::iterator I = MBB.end();
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|   if (I == MBB.begin() || !isUnpredicatedTerminator(--I))
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|     return false;
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| 
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|   // Get the last instruction in the block.
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|   MachineInstr *LastInst = I;
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|   
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|   // If there is only one terminator instruction, process it.
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|   if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
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|     if (LastInst->getOpcode() == Alpha::BR) {
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|       TBB = LastInst->getOperand(0).getMachineBasicBlock();
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|       return false;
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|     } else if (LastInst->getOpcode() == Alpha::COND_BRANCH_I ||
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|                LastInst->getOpcode() == Alpha::COND_BRANCH_F) {
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|       // Block ends with fall-through condbranch.
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|       TBB = LastInst->getOperand(2).getMachineBasicBlock();
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|       Cond.push_back(LastInst->getOperand(0));
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|       Cond.push_back(LastInst->getOperand(1));
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|       return false;
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|     }
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|     // Otherwise, don't know what this is.
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|     return true;
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|   }
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|   
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|   // Get the instruction before it if it's a terminator.
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|   MachineInstr *SecondLastInst = I;
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| 
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|   // If there are three terminators, we don't know what sort of block this is.
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|   if (SecondLastInst && I != MBB.begin() &&
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|       isUnpredicatedTerminator(--I))
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|     return true;
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|   
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|   // If the block ends with Alpha::BR and Alpha::COND_BRANCH_*, handle it.
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|   if ((SecondLastInst->getOpcode() == Alpha::COND_BRANCH_I ||
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|       SecondLastInst->getOpcode() == Alpha::COND_BRANCH_F) && 
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|       LastInst->getOpcode() == Alpha::BR) {
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|     TBB =  SecondLastInst->getOperand(2).getMachineBasicBlock();
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|     Cond.push_back(SecondLastInst->getOperand(0));
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|     Cond.push_back(SecondLastInst->getOperand(1));
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|     FBB = LastInst->getOperand(0).getMachineBasicBlock();
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|     return false;
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|   }
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|   
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|   // If the block ends with two Alpha::BRs, handle it.  The second one is not
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|   // executed, so remove it.
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|   if (SecondLastInst->getOpcode() == Alpha::BR && 
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|       LastInst->getOpcode() == Alpha::BR) {
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|     TBB = SecondLastInst->getOperand(0).getMachineBasicBlock();
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|     I = LastInst;
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|     I->eraseFromParent();
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|     return false;
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|   }
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| 
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|   // Otherwise, can't handle this.
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|   return true;
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| }
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| 
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| unsigned AlphaInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
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|   MachineBasicBlock::iterator I = MBB.end();
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|   if (I == MBB.begin()) return 0;
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|   --I;
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|   if (I->getOpcode() != Alpha::BR && 
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|       I->getOpcode() != Alpha::COND_BRANCH_I &&
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|       I->getOpcode() != Alpha::COND_BRANCH_F)
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|     return 0;
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|   
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|   // Remove the branch.
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|   I->eraseFromParent();
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|   
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|   I = MBB.end();
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| 
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|   if (I == MBB.begin()) return 1;
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|   --I;
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|   if (I->getOpcode() != Alpha::COND_BRANCH_I && 
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|       I->getOpcode() != Alpha::COND_BRANCH_F)
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|     return 1;
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|   
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|   // Remove the branch.
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|   I->eraseFromParent();
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|   return 2;
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| }
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| 
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| void AlphaInstrInfo::insertNoop(MachineBasicBlock &MBB, 
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|                                 MachineBasicBlock::iterator MI) const {
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|   BuildMI(MBB, MI, get(Alpha::BISr), Alpha::R31).addReg(Alpha::R31)
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|     .addReg(Alpha::R31);
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| }
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| 
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| bool AlphaInstrInfo::BlockHasNoFallThrough(MachineBasicBlock &MBB) const {
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|   if (MBB.empty()) return false;
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|   
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|   switch (MBB.back().getOpcode()) {
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|   case Alpha::RETDAG: // Return.
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|   case Alpha::RETDAGp:
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|   case Alpha::BR:     // Uncond branch.
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|   case Alpha::JMP:  // Indirect branch.
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|     return true;
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|   default: return false;
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|   }
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| }
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| bool AlphaInstrInfo::
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| ReverseBranchCondition(std::vector<MachineOperand> &Cond) const {
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|   assert(Cond.size() == 2 && "Invalid Alpha branch opcode!");
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|   Cond[0].setImm(AlphaRevCondCode(Cond[0].getImm()));
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|   return false;
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| }
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| 
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