llvm-6502/lib/Target/Mips/Mips16InstrInfo.cpp
Reed Kotler 6b9d461780 For Mips 16, add the optimization where the 16 bit form of addiu sp can be used
if the offset fits in 11 bits. This makes use of the fact that the abi
requires sp to be 8 byte aligned so the actual offset can fit in 8
bits. It will be shifted left and sign extended before being actually used.
The assembler or direct object emitter will shift right the 11 bit
signed field by 3 bits. We don't need to deal with that here.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175073 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-13 20:28:27 +00:00

415 lines
15 KiB
C++

//===-- Mips16InstrInfo.cpp - Mips16 Instruction Information --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the Mips16 implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "Mips16InstrInfo.h"
#include "InstPrinter/MipsInstPrinter.h"
#include "MipsMachineFunction.h"
#include "MipsTargetMachine.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
static cl::opt<bool> NeverUseSaveRestore(
"mips16-never-use-save-restore",
cl::init(false),
cl::desc("For testing ability to adjust stack pointer "
"without save/restore instruction"),
cl::Hidden);
Mips16InstrInfo::Mips16InstrInfo(MipsTargetMachine &tm)
: MipsInstrInfo(tm, Mips::BimmX16),
RI(*tm.getSubtargetImpl(), *this) {}
const MipsRegisterInfo &Mips16InstrInfo::getRegisterInfo() const {
return RI;
}
/// isLoadFromStackSlot - If the specified machine instruction is a direct
/// load from a stack slot, return the virtual or physical register number of
/// the destination along with the FrameIndex of the loaded stack slot. If
/// not, return 0. This predicate must return 0 if the instruction has
/// any side effects other than loading from the stack slot.
unsigned Mips16InstrInfo::
isLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const
{
return 0;
}
/// isStoreToStackSlot - If the specified machine instruction is a direct
/// store to a stack slot, return the virtual or physical register number of
/// the source reg along with the FrameIndex of the loaded stack slot. If
/// not, return 0. This predicate must return 0 if the instruction has
/// any side effects other than storing to the stack slot.
unsigned Mips16InstrInfo::
isStoreToStackSlot(const MachineInstr *MI, int &FrameIndex) const
{
return 0;
}
void Mips16InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I, DebugLoc DL,
unsigned DestReg, unsigned SrcReg,
bool KillSrc) const {
unsigned Opc = 0;
if (Mips::CPU16RegsRegClass.contains(DestReg) &&
Mips::CPURegsRegClass.contains(SrcReg))
Opc = Mips::MoveR3216;
else if (Mips::CPURegsRegClass.contains(DestReg) &&
Mips::CPU16RegsRegClass.contains(SrcReg))
Opc = Mips::Move32R16;
else if ((SrcReg == Mips::HI) &&
(Mips::CPU16RegsRegClass.contains(DestReg)))
Opc = Mips::Mfhi16, SrcReg = 0;
else if ((SrcReg == Mips::LO) &&
(Mips::CPU16RegsRegClass.contains(DestReg)))
Opc = Mips::Mflo16, SrcReg = 0;
assert(Opc && "Cannot copy registers");
MachineInstrBuilder MIB = BuildMI(MBB, I, DL, get(Opc));
if (DestReg)
MIB.addReg(DestReg, RegState::Define);
if (SrcReg)
MIB.addReg(SrcReg, getKillRegState(KillSrc));
}
void Mips16InstrInfo::
storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned SrcReg, bool isKill, int FI,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const {
DebugLoc DL;
if (I != MBB.end()) DL = I->getDebugLoc();
MachineMemOperand *MMO = GetMemOperand(MBB, FI, MachineMemOperand::MOStore);
unsigned Opc = 0;
if (Mips::CPU16RegsRegClass.hasSubClassEq(RC))
Opc = Mips::SwRxSpImmX16;
assert(Opc && "Register class not handled!");
BuildMI(MBB, I, DL, get(Opc)).addReg(SrcReg, getKillRegState(isKill))
.addFrameIndex(FI).addImm(0).addMemOperand(MMO);
}
void Mips16InstrInfo::
loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned DestReg, int FI,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const {
DebugLoc DL;
if (I != MBB.end()) DL = I->getDebugLoc();
MachineMemOperand *MMO = GetMemOperand(MBB, FI, MachineMemOperand::MOLoad);
unsigned Opc = 0;
if (Mips::CPU16RegsRegClass.hasSubClassEq(RC))
Opc = Mips::LwRxSpImmX16;
assert(Opc && "Register class not handled!");
BuildMI(MBB, I, DL, get(Opc), DestReg).addFrameIndex(FI).addImm(0)
.addMemOperand(MMO);
}
bool Mips16InstrInfo::expandPostRAPseudo(MachineBasicBlock::iterator MI) const {
MachineBasicBlock &MBB = *MI->getParent();
switch(MI->getDesc().getOpcode()) {
default:
return false;
case Mips::RetRA16:
ExpandRetRA16(MBB, MI, Mips::JrcRa16);
break;
}
MBB.erase(MI);
return true;
}
/// GetOppositeBranchOpc - Return the inverse of the specified
/// opcode, e.g. turning BEQ to BNE.
unsigned Mips16InstrInfo::GetOppositeBranchOpc(unsigned Opc) const {
switch (Opc) {
default: llvm_unreachable("Illegal opcode!");
case Mips::BeqzRxImmX16: return Mips::BnezRxImmX16;
case Mips::BnezRxImmX16: return Mips::BeqzRxImmX16;
case Mips::BteqzT8CmpX16: return Mips::BtnezT8CmpX16;
case Mips::BteqzT8SltX16: return Mips::BtnezT8SltX16;
case Mips::BteqzT8SltiX16: return Mips::BtnezT8SltiX16;
case Mips::BtnezX16: return Mips::BteqzX16;
case Mips::BtnezT8CmpiX16: return Mips::BteqzT8CmpiX16;
case Mips::BtnezT8SltuX16: return Mips::BteqzT8SltuX16;
case Mips::BtnezT8SltiuX16: return Mips::BteqzT8SltiuX16;
case Mips::BteqzX16: return Mips::BtnezX16;
case Mips::BteqzT8CmpiX16: return Mips::BtnezT8CmpiX16;
case Mips::BteqzT8SltuX16: return Mips::BtnezT8SltuX16;
case Mips::BteqzT8SltiuX16: return Mips::BtnezT8SltiuX16;
case Mips::BtnezT8CmpX16: return Mips::BteqzT8CmpX16;
case Mips::BtnezT8SltX16: return Mips::BteqzT8SltX16;
case Mips::BtnezT8SltiX16: return Mips::BteqzT8SltiX16;
}
assert(false && "Implement this function.");
return 0;
}
// Adjust SP by FrameSize bytes. Save RA, S0, S1
void Mips16InstrInfo::makeFrame(unsigned SP, int64_t FrameSize,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
if (!NeverUseSaveRestore) {
if (isUInt<11>(FrameSize))
BuildMI(MBB, I, DL, get(Mips::SaveRaF16)).addImm(FrameSize);
else {
int Base = 2040; // should create template function like isUInt that
// returns largest possible n bit unsigned integer
int64_t Remainder = FrameSize - Base;
BuildMI(MBB, I, DL, get(Mips::SaveRaF16)). addImm(Base);
if (isInt<16>(-Remainder))
BuildAddiuSpImm(MBB, I, DL, -Remainder);
else
adjustStackPtrBig(SP, -Remainder, MBB, I, Mips::V0, Mips::V1);
}
}
else {
//
// sw ra, -4[sp]
// sw s1, -8[sp]
// sw s0, -12[sp]
MachineInstrBuilder MIB1 = BuildMI(MBB, I, DL, get(Mips::SwRxSpImmX16),
Mips::RA);
MIB1.addReg(Mips::SP);
MIB1.addImm(-4);
MachineInstrBuilder MIB2 = BuildMI(MBB, I, DL, get(Mips::SwRxSpImmX16),
Mips::S1);
MIB2.addReg(Mips::SP);
MIB2.addImm(-8);
MachineInstrBuilder MIB3 = BuildMI(MBB, I, DL, get(Mips::SwRxSpImmX16),
Mips::S0);
MIB3.addReg(Mips::SP);
MIB3.addImm(-12);
adjustStackPtrBig(SP, -FrameSize, MBB, I, Mips::V0, Mips::V1);
}
}
// Adjust SP by FrameSize bytes. Restore RA, S0, S1
void Mips16InstrInfo::restoreFrame(unsigned SP, int64_t FrameSize,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
if (!NeverUseSaveRestore) {
if (isUInt<11>(FrameSize))
BuildMI(MBB, I, DL, get(Mips::RestoreRaF16)).addImm(FrameSize);
else {
int Base = 2040; // should create template function like isUInt that
// returns largest possible n bit unsigned integer
int64_t Remainder = FrameSize - Base;
if (isInt<16>(Remainder))
BuildAddiuSpImm(MBB, I, DL, Remainder);
else
adjustStackPtrBig(SP, Remainder, MBB, I, Mips::A0, Mips::A1);
BuildMI(MBB, I, DL, get(Mips::RestoreRaF16)). addImm(Base);
}
}
else {
adjustStackPtrBig(SP, FrameSize, MBB, I, Mips::A0, Mips::A1);
// lw ra, -4[sp]
// lw s1, -8[sp]
// lw s0, -12[sp]
MachineInstrBuilder MIB1 = BuildMI(MBB, I, DL, get(Mips::LwRxSpImmX16),
Mips::A0);
MIB1.addReg(Mips::SP);
MIB1.addImm(-4);
MachineInstrBuilder MIB0 = BuildMI(MBB, I, DL, get(Mips::Move32R16),
Mips::RA);
MIB0.addReg(Mips::A0);
MachineInstrBuilder MIB2 = BuildMI(MBB, I, DL, get(Mips::LwRxSpImmX16),
Mips::S1);
MIB2.addReg(Mips::SP);
MIB2.addImm(-8);
MachineInstrBuilder MIB3 = BuildMI(MBB, I, DL, get(Mips::LwRxSpImmX16),
Mips::S0);
MIB3.addReg(Mips::SP);
MIB3.addImm(-12);
}
}
// Adjust SP by Amount bytes where bytes can be up to 32bit number.
// This can only be called at times that we know that there is at least one free
// register.
// This is clearly safe at prologue and epilogue.
//
void Mips16InstrInfo::adjustStackPtrBig(unsigned SP, int64_t Amount,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned Reg1, unsigned Reg2) const {
DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
// MachineRegisterInfo &RegInfo = MBB.getParent()->getRegInfo();
// unsigned Reg1 = RegInfo.createVirtualRegister(&Mips::CPU16RegsRegClass);
// unsigned Reg2 = RegInfo.createVirtualRegister(&Mips::CPU16RegsRegClass);
//
// li reg1, constant
// move reg2, sp
// add reg1, reg1, reg2
// move sp, reg1
//
//
MachineInstrBuilder MIB1 = BuildMI(MBB, I, DL, get(Mips::LwConstant32), Reg1);
MIB1.addImm(Amount);
MachineInstrBuilder MIB2 = BuildMI(MBB, I, DL, get(Mips::MoveR3216), Reg2);
MIB2.addReg(Mips::SP, RegState::Kill);
MachineInstrBuilder MIB3 = BuildMI(MBB, I, DL, get(Mips::AdduRxRyRz16), Reg1);
MIB3.addReg(Reg1);
MIB3.addReg(Reg2, RegState::Kill);
MachineInstrBuilder MIB4 = BuildMI(MBB, I, DL, get(Mips::Move32R16),
Mips::SP);
MIB4.addReg(Reg1, RegState::Kill);
}
void Mips16InstrInfo::adjustStackPtrBigUnrestricted(unsigned SP, int64_t Amount,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
assert(false && "adjust stack pointer amount exceeded");
}
/// Adjust SP by Amount bytes.
void Mips16InstrInfo::adjustStackPtr(unsigned SP, int64_t Amount,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
if (isInt<16>(Amount)) // need to change to addiu sp, ....and isInt<16>
BuildAddiuSpImm(MBB, I, DL, Amount);
else
adjustStackPtrBigUnrestricted(SP, Amount, MBB, I);
}
/// This function generates the sequence of instructions needed to get the
/// result of adding register REG and immediate IMM.
unsigned
Mips16InstrInfo::loadImmediate(unsigned FrameReg,
int64_t Imm, MachineBasicBlock &MBB,
MachineBasicBlock::iterator II, DebugLoc DL,
unsigned &NewImm) const {
//
// given original instruction is:
// Instr rx, T[offset] where offset is too big.
//
// lo = offset & 0xFFFF
// hi = ((offset >> 16) + (lo >> 15)) & 0xFFFF;
//
// let T = temporary register
// li T, hi
// shl T, 16
// add T, Rx, T
//
RegScavenger rs;
int32_t lo = Imm & 0xFFFF;
int32_t hi = ((Imm >> 16) + (lo >> 15)) & 0xFFFF;
NewImm = lo;
unsigned Reg =0;
unsigned SpReg = 0;
rs.enterBasicBlock(&MBB);
rs.forward(II);
//
// we use T0 for the first register, if we need to save something away.
// we use T1 for the second register, if we need to save something away.
//
unsigned FirstRegSaved =0, SecondRegSaved=0;
unsigned FirstRegSavedTo = 0, SecondRegSavedTo = 0;
Reg = rs.FindUnusedReg(&Mips::CPU16RegsRegClass);
if (Reg == 0) {
FirstRegSaved = Reg = Mips::V0;
FirstRegSavedTo = Mips::T0;
copyPhysReg(MBB, II, DL, FirstRegSavedTo, FirstRegSaved, true);
}
else
rs.setUsed(Reg);
BuildMI(MBB, II, DL, get(Mips::LiRxImmX16), Reg).addImm(hi);
BuildMI(MBB, II, DL, get(Mips::SllX16), Reg).addReg(Reg).
addImm(16);
if (FrameReg == Mips::SP) {
SpReg = rs.FindUnusedReg(&Mips::CPU16RegsRegClass);
if (SpReg == 0) {
if (Reg != Mips::V1) {
SecondRegSaved = SpReg = Mips::V1;
SecondRegSavedTo = Mips::T1;
}
else {
SecondRegSaved = SpReg = Mips::V0;
SecondRegSavedTo = Mips::T0;
}
copyPhysReg(MBB, II, DL, SecondRegSavedTo, SecondRegSaved, true);
}
else
rs.setUsed(SpReg);
copyPhysReg(MBB, II, DL, SpReg, Mips::SP, false);
BuildMI(MBB, II, DL, get(Mips:: AdduRxRyRz16), Reg).addReg(SpReg)
.addReg(Reg);
}
else
BuildMI(MBB, II, DL, get(Mips:: AdduRxRyRz16), Reg).addReg(FrameReg)
.addReg(Reg, RegState::Kill);
if (FirstRegSaved || SecondRegSaved) {
II = llvm::next(II);
if (FirstRegSaved)
copyPhysReg(MBB, II, DL, FirstRegSaved, FirstRegSavedTo, true);
if (SecondRegSaved)
copyPhysReg(MBB, II, DL, SecondRegSaved, SecondRegSavedTo, true);
}
return Reg;
}
unsigned Mips16InstrInfo::GetAnalyzableBrOpc(unsigned Opc) const {
return (Opc == Mips::BeqzRxImmX16 || Opc == Mips::BimmX16 ||
Opc == Mips::BnezRxImmX16 || Opc == Mips::BteqzX16 ||
Opc == Mips::BteqzT8CmpX16 || Opc == Mips::BteqzT8CmpiX16 ||
Opc == Mips::BteqzT8SltX16 || Opc == Mips::BteqzT8SltuX16 ||
Opc == Mips::BteqzT8SltiX16 || Opc == Mips::BteqzT8SltiuX16 ||
Opc == Mips::BtnezX16 || Opc == Mips::BtnezT8CmpX16 ||
Opc == Mips::BtnezT8CmpiX16 || Opc == Mips::BtnezT8SltX16 ||
Opc == Mips::BtnezT8SltuX16 || Opc == Mips::BtnezT8SltiX16 ||
Opc == Mips::BtnezT8SltiuX16 ) ? Opc : 0;
}
void Mips16InstrInfo::ExpandRetRA16(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned Opc) const {
BuildMI(MBB, I, I->getDebugLoc(), get(Opc));
}
void Mips16InstrInfo::BuildAddiuSpImm(
MachineBasicBlock &MBB,
MachineBasicBlock::iterator II, DebugLoc DL, int64_t Imm) const {
if (validSpImm8(Imm))
BuildMI(MBB, II, DL, get(Mips::AddiuSpImm16)).addImm(Imm);
else
BuildMI(MBB, II, DL, get(Mips::AddiuSpImmX16)).addImm(Imm);
}
const MipsInstrInfo *llvm::createMips16InstrInfo(MipsTargetMachine &TM) {
return new Mips16InstrInfo(TM);
}