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https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123399 91177308-0d34-0410-b5e6-96231b3b80d8
224 lines
7.6 KiB
C++
224 lines
7.6 KiB
C++
//======-- MSP430FrameLowering.cpp - MSP430 Frame Information -------=========//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// 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 MSP430 implementation of TargetFrameLowering class.
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//
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//===----------------------------------------------------------------------===//
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#include "MSP430FrameLowering.h"
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#include "MSP430InstrInfo.h"
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#include "MSP430MachineFunctionInfo.h"
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#include "llvm/Function.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Support/CommandLine.h"
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using namespace llvm;
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bool MSP430FrameLowering::hasFP(const MachineFunction &MF) const {
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const MachineFrameInfo *MFI = MF.getFrameInfo();
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return (DisableFramePointerElim(MF) ||
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MF.getFrameInfo()->hasVarSizedObjects() ||
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MFI->isFrameAddressTaken());
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}
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bool MSP430FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
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return !MF.getFrameInfo()->hasVarSizedObjects();
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}
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void MSP430FrameLowering::emitPrologue(MachineFunction &MF) const {
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MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
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MachineFrameInfo *MFI = MF.getFrameInfo();
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MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>();
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const MSP430InstrInfo &TII =
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*static_cast<const MSP430InstrInfo*>(MF.getTarget().getInstrInfo());
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MachineBasicBlock::iterator MBBI = MBB.begin();
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DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
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// Get the number of bytes to allocate from the FrameInfo.
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uint64_t StackSize = MFI->getStackSize();
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uint64_t NumBytes = 0;
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if (hasFP(MF)) {
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// Calculate required stack adjustment
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uint64_t FrameSize = StackSize - 2;
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NumBytes = FrameSize - MSP430FI->getCalleeSavedFrameSize();
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// Get the offset of the stack slot for the EBP register... which is
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// guaranteed to be the last slot by processFunctionBeforeFrameFinalized.
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// Update the frame offset adjustment.
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MFI->setOffsetAdjustment(-NumBytes);
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// Save FPW into the appropriate stack slot...
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BuildMI(MBB, MBBI, DL, TII.get(MSP430::PUSH16r))
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.addReg(MSP430::FPW, RegState::Kill);
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// Update FPW with the new base value...
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BuildMI(MBB, MBBI, DL, TII.get(MSP430::MOV16rr), MSP430::FPW)
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.addReg(MSP430::SPW);
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// Mark the FramePtr as live-in in every block except the entry.
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for (MachineFunction::iterator I = llvm::next(MF.begin()), E = MF.end();
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I != E; ++I)
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I->addLiveIn(MSP430::FPW);
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} else
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NumBytes = StackSize - MSP430FI->getCalleeSavedFrameSize();
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// Skip the callee-saved push instructions.
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while (MBBI != MBB.end() && (MBBI->getOpcode() == MSP430::PUSH16r))
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++MBBI;
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if (MBBI != MBB.end())
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DL = MBBI->getDebugLoc();
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if (NumBytes) { // adjust stack pointer: SPW -= numbytes
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// If there is an SUB16ri of SPW immediately before this instruction, merge
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// the two.
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//NumBytes -= mergeSPUpdates(MBB, MBBI, true);
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// If there is an ADD16ri or SUB16ri of SPW immediately after this
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// instruction, merge the two instructions.
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// mergeSPUpdatesDown(MBB, MBBI, &NumBytes);
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if (NumBytes) {
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MachineInstr *MI =
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BuildMI(MBB, MBBI, DL, TII.get(MSP430::SUB16ri), MSP430::SPW)
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.addReg(MSP430::SPW).addImm(NumBytes);
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// The SRW implicit def is dead.
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MI->getOperand(3).setIsDead();
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}
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}
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}
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void MSP430FrameLowering::emitEpilogue(MachineFunction &MF,
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MachineBasicBlock &MBB) const {
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const MachineFrameInfo *MFI = MF.getFrameInfo();
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MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>();
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const MSP430InstrInfo &TII =
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*static_cast<const MSP430InstrInfo*>(MF.getTarget().getInstrInfo());
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MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
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unsigned RetOpcode = MBBI->getOpcode();
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DebugLoc DL = MBBI->getDebugLoc();
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switch (RetOpcode) {
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case MSP430::RET:
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case MSP430::RETI: break; // These are ok
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default:
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llvm_unreachable("Can only insert epilog into returning blocks");
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}
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// Get the number of bytes to allocate from the FrameInfo
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uint64_t StackSize = MFI->getStackSize();
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unsigned CSSize = MSP430FI->getCalleeSavedFrameSize();
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uint64_t NumBytes = 0;
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if (hasFP(MF)) {
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// Calculate required stack adjustment
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uint64_t FrameSize = StackSize - 2;
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NumBytes = FrameSize - CSSize;
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// pop FPW.
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BuildMI(MBB, MBBI, DL, TII.get(MSP430::POP16r), MSP430::FPW);
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} else
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NumBytes = StackSize - CSSize;
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// Skip the callee-saved pop instructions.
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while (MBBI != MBB.begin()) {
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MachineBasicBlock::iterator PI = prior(MBBI);
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unsigned Opc = PI->getOpcode();
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if (Opc != MSP430::POP16r && !PI->getDesc().isTerminator())
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break;
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--MBBI;
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}
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DL = MBBI->getDebugLoc();
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// If there is an ADD16ri or SUB16ri of SPW immediately before this
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// instruction, merge the two instructions.
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//if (NumBytes || MFI->hasVarSizedObjects())
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// mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);
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if (MFI->hasVarSizedObjects()) {
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BuildMI(MBB, MBBI, DL,
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TII.get(MSP430::MOV16rr), MSP430::SPW).addReg(MSP430::FPW);
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if (CSSize) {
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MachineInstr *MI =
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BuildMI(MBB, MBBI, DL,
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TII.get(MSP430::SUB16ri), MSP430::SPW)
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.addReg(MSP430::SPW).addImm(CSSize);
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// The SRW implicit def is dead.
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MI->getOperand(3).setIsDead();
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}
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} else {
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// adjust stack pointer back: SPW += numbytes
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if (NumBytes) {
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MachineInstr *MI =
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BuildMI(MBB, MBBI, DL, TII.get(MSP430::ADD16ri), MSP430::SPW)
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.addReg(MSP430::SPW).addImm(NumBytes);
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// The SRW implicit def is dead.
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MI->getOperand(3).setIsDead();
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}
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}
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}
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// FIXME: Can we eleminate these in favour of generic code?
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bool
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MSP430FrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MI,
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const std::vector<CalleeSavedInfo> &CSI,
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const TargetRegisterInfo *TRI) const {
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if (CSI.empty())
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return false;
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DebugLoc DL;
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if (MI != MBB.end()) DL = MI->getDebugLoc();
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MachineFunction &MF = *MBB.getParent();
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const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
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MSP430MachineFunctionInfo *MFI = MF.getInfo<MSP430MachineFunctionInfo>();
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MFI->setCalleeSavedFrameSize(CSI.size() * 2);
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for (unsigned i = CSI.size(); i != 0; --i) {
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unsigned Reg = CSI[i-1].getReg();
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// Add the callee-saved register as live-in. It's killed at the spill.
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MBB.addLiveIn(Reg);
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BuildMI(MBB, MI, DL, TII.get(MSP430::PUSH16r))
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.addReg(Reg, RegState::Kill);
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}
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return true;
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}
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bool
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MSP430FrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MI,
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const std::vector<CalleeSavedInfo> &CSI,
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const TargetRegisterInfo *TRI) const {
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if (CSI.empty())
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return false;
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DebugLoc DL;
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if (MI != MBB.end()) DL = MI->getDebugLoc();
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MachineFunction &MF = *MBB.getParent();
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const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
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for (unsigned i = 0, e = CSI.size(); i != e; ++i)
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BuildMI(MBB, MI, DL, TII.get(MSP430::POP16r), CSI[i].getReg());
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return true;
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}
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