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llvm-mirror/lib/Target/AVR/AVRRelaxMemOperations.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

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3.9 KiB
C++

//===-- AVRRelaxMemOperations.cpp - Relax out of range loads/stores -------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains a pass which relaxes out of range memory operations into
// equivalent operations which handle bigger addresses.
//
//===----------------------------------------------------------------------===//
#include "AVR.h"
#include "AVRInstrInfo.h"
#include "AVRTargetMachine.h"
#include "MCTargetDesc/AVRMCTargetDesc.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
using namespace llvm;
#define AVR_RELAX_MEM_OPS_NAME "AVR memory operation relaxation pass"
namespace {
class AVRRelaxMem : public MachineFunctionPass {
public:
static char ID;
AVRRelaxMem() : MachineFunctionPass(ID) {
initializeAVRRelaxMemPass(*PassRegistry::getPassRegistry());
}
bool runOnMachineFunction(MachineFunction &MF) override;
StringRef getPassName() const override { return AVR_RELAX_MEM_OPS_NAME; }
private:
typedef MachineBasicBlock Block;
typedef Block::iterator BlockIt;
const TargetInstrInfo *TII;
template <unsigned OP> bool relax(Block &MBB, BlockIt MBBI);
bool runOnBasicBlock(Block &MBB);
bool runOnInstruction(Block &MBB, BlockIt MBBI);
MachineInstrBuilder buildMI(Block &MBB, BlockIt MBBI, unsigned Opcode) {
return BuildMI(MBB, MBBI, MBBI->getDebugLoc(), TII->get(Opcode));
}
};
char AVRRelaxMem::ID = 0;
bool AVRRelaxMem::runOnMachineFunction(MachineFunction &MF) {
bool Modified = false;
const AVRSubtarget &STI = MF.getSubtarget<AVRSubtarget>();
TII = STI.getInstrInfo();
for (Block &MBB : MF) {
bool BlockModified = runOnBasicBlock(MBB);
Modified |= BlockModified;
}
return Modified;
}
bool AVRRelaxMem::runOnBasicBlock(Block &MBB) {
bool Modified = false;
BlockIt MBBI = MBB.begin(), E = MBB.end();
while (MBBI != E) {
BlockIt NMBBI = std::next(MBBI);
Modified |= runOnInstruction(MBB, MBBI);
MBBI = NMBBI;
}
return Modified;
}
template <>
bool AVRRelaxMem::relax<AVR::STDWPtrQRr>(Block &MBB, BlockIt MBBI) {
MachineInstr &MI = *MBBI;
MachineOperand &Ptr = MI.getOperand(0);
MachineOperand &Src = MI.getOperand(2);
int64_t Imm = MI.getOperand(1).getImm();
// We can definitely optimise this better.
if (Imm > 63) {
// Push the previous state of the pointer register.
// This instruction must preserve the value.
buildMI(MBB, MBBI, AVR::PUSHWRr)
.addReg(Ptr.getReg());
// Add the immediate to the pointer register.
buildMI(MBB, MBBI, AVR::SBCIWRdK)
.addReg(Ptr.getReg(), RegState::Define)
.addReg(Ptr.getReg())
.addImm(-Imm);
// Store the value in the source register to the address
// pointed to by the pointer register.
buildMI(MBB, MBBI, AVR::STWPtrRr)
.addReg(Ptr.getReg())
.addReg(Src.getReg(), getKillRegState(Src.isKill()));
// Pop the original state of the pointer register.
buildMI(MBB, MBBI, AVR::POPWRd)
.addReg(Ptr.getReg(), getKillRegState(Ptr.isKill()));
MI.removeFromParent();
}
return false;
}
bool AVRRelaxMem::runOnInstruction(Block &MBB, BlockIt MBBI) {
MachineInstr &MI = *MBBI;
int Opcode = MBBI->getOpcode();
#define RELAX(Op) \
case Op: \
return relax<Op>(MBB, MI)
switch (Opcode) {
RELAX(AVR::STDWPtrQRr);
}
#undef RELAX
return false;
}
} // end of anonymous namespace
INITIALIZE_PASS(AVRRelaxMem, "avr-relax-mem",
AVR_RELAX_MEM_OPS_NAME, false, false)
namespace llvm {
FunctionPass *createAVRRelaxMemPass() { return new AVRRelaxMem(); }
} // end of namespace llvm