llvm-6502/lib/Target/Mips/MipsInstrInfo.cpp
Dan Gohman 9911405183 Convert Alpha and Mips to use a MachineFunctionInfo subclass to
carry GlobalBaseReg, and GlobalRetAddr too in Alpha's case. This
eliminates the need for them to search through the
MachineRegisterInfo livein list in order to identify these
virtual registers. EmitLiveInCopies is now the only user of the
virtual register portion of MachineRegisterInfo's livein data.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72802 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-03 20:30:14 +00:00

653 lines
22 KiB
C++

//===- MipsInstrInfo.cpp - Mips Instruction Information ---------*- C++ -*-===//
//
// 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 Mips implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "MipsInstrInfo.h"
#include "MipsTargetMachine.h"
#include "MipsMachineFunction.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "MipsGenInstrInfo.inc"
using namespace llvm;
MipsInstrInfo::MipsInstrInfo(MipsTargetMachine &tm)
: TargetInstrInfoImpl(MipsInsts, array_lengthof(MipsInsts)),
TM(tm), RI(*TM.getSubtargetImpl(), *this) {}
static bool isZeroImm(const MachineOperand &op) {
return op.isImm() && op.getImm() == 0;
}
/// Return true if the instruction is a register to register move and
/// leave the source and dest operands in the passed parameters.
bool MipsInstrInfo::
isMoveInstr(const MachineInstr &MI, unsigned &SrcReg, unsigned &DstReg,
unsigned &SrcSubIdx, unsigned &DstSubIdx) const
{
SrcSubIdx = DstSubIdx = 0; // No sub-registers.
// addu $dst, $src, $zero || addu $dst, $zero, $src
// or $dst, $src, $zero || or $dst, $zero, $src
if ((MI.getOpcode() == Mips::ADDu) || (MI.getOpcode() == Mips::OR)) {
if (MI.getOperand(1).getReg() == Mips::ZERO) {
DstReg = MI.getOperand(0).getReg();
SrcReg = MI.getOperand(2).getReg();
return true;
} else if (MI.getOperand(2).getReg() == Mips::ZERO) {
DstReg = MI.getOperand(0).getReg();
SrcReg = MI.getOperand(1).getReg();
return true;
}
}
// mov $fpDst, $fpSrc
// mfc $gpDst, $fpSrc
// mtc $fpDst, $gpSrc
if (MI.getOpcode() == Mips::FMOV_S32 ||
MI.getOpcode() == Mips::FMOV_D32 ||
MI.getOpcode() == Mips::MFC1 ||
MI.getOpcode() == Mips::MTC1 ||
MI.getOpcode() == Mips::MOVCCRToCCR) {
DstReg = MI.getOperand(0).getReg();
SrcReg = MI.getOperand(1).getReg();
return true;
}
// addiu $dst, $src, 0
if (MI.getOpcode() == Mips::ADDiu) {
if ((MI.getOperand(1).isReg()) && (isZeroImm(MI.getOperand(2)))) {
DstReg = MI.getOperand(0).getReg();
SrcReg = MI.getOperand(1).getReg();
return true;
}
}
return false;
}
/// 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 MipsInstrInfo::
isLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const
{
if ((MI->getOpcode() == Mips::LW) || (MI->getOpcode() == Mips::LWC1) ||
(MI->getOpcode() == Mips::LDC1)) {
if ((MI->getOperand(2).isFI()) && // is a stack slot
(MI->getOperand(1).isImm()) && // the imm is zero
(isZeroImm(MI->getOperand(1)))) {
FrameIndex = MI->getOperand(2).getIndex();
return MI->getOperand(0).getReg();
}
}
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 MipsInstrInfo::
isStoreToStackSlot(const MachineInstr *MI, int &FrameIndex) const
{
if ((MI->getOpcode() == Mips::SW) || (MI->getOpcode() == Mips::SWC1) ||
(MI->getOpcode() == Mips::SDC1)) {
if ((MI->getOperand(2).isFI()) && // is a stack slot
(MI->getOperand(1).isImm()) && // the imm is zero
(isZeroImm(MI->getOperand(1)))) {
FrameIndex = MI->getOperand(2).getIndex();
return MI->getOperand(0).getReg();
}
}
return 0;
}
/// insertNoop - If data hazard condition is found insert the target nop
/// instruction.
void MipsInstrInfo::
insertNoop(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI) const
{
DebugLoc DL = DebugLoc::getUnknownLoc();
if (MI != MBB.end()) DL = MI->getDebugLoc();
BuildMI(MBB, MI, DL, get(Mips::NOP));
}
bool MipsInstrInfo::
copyRegToReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned DestReg, unsigned SrcReg,
const TargetRegisterClass *DestRC,
const TargetRegisterClass *SrcRC) const {
DebugLoc DL = DebugLoc::getUnknownLoc();
if (I != MBB.end()) DL = I->getDebugLoc();
if (DestRC != SrcRC) {
// Copy to/from FCR31 condition register
if ((DestRC == Mips::CPURegsRegisterClass) &&
(SrcRC == Mips::CCRRegisterClass))
BuildMI(MBB, I, DL, get(Mips::CFC1), DestReg).addReg(SrcReg);
else if ((DestRC == Mips::CCRRegisterClass) &&
(SrcRC == Mips::CPURegsRegisterClass))
BuildMI(MBB, I, DL, get(Mips::CTC1), DestReg).addReg(SrcReg);
// Moves between coprocessors and cpu
else if ((DestRC == Mips::CPURegsRegisterClass) &&
(SrcRC == Mips::FGR32RegisterClass))
BuildMI(MBB, I, DL, get(Mips::MFC1), DestReg).addReg(SrcReg);
else if ((DestRC == Mips::FGR32RegisterClass) &&
(SrcRC == Mips::CPURegsRegisterClass))
BuildMI(MBB, I, DL, get(Mips::MTC1), DestReg).addReg(SrcReg);
// Move from/to Hi/Lo registers
else if ((DestRC == Mips::HILORegisterClass) &&
(SrcRC == Mips::CPURegsRegisterClass)) {
unsigned Opc = (DestReg == Mips::HI) ? Mips::MTHI : Mips::MTLO;
BuildMI(MBB, I, DL, get(Opc), DestReg);
} else if ((SrcRC == Mips::HILORegisterClass) &&
(DestRC == Mips::CPURegsRegisterClass)) {
unsigned Opc = (SrcReg == Mips::HI) ? Mips::MFHI : Mips::MFLO;
BuildMI(MBB, I, DL, get(Opc), DestReg);
// Can't copy this register
} else
return false;
return true;
}
if (DestRC == Mips::CPURegsRegisterClass)
BuildMI(MBB, I, DL, get(Mips::ADDu), DestReg).addReg(Mips::ZERO)
.addReg(SrcReg);
else if (DestRC == Mips::FGR32RegisterClass)
BuildMI(MBB, I, DL, get(Mips::FMOV_S32), DestReg).addReg(SrcReg);
else if (DestRC == Mips::AFGR64RegisterClass)
BuildMI(MBB, I, DL, get(Mips::FMOV_D32), DestReg).addReg(SrcReg);
else if (DestRC == Mips::CCRRegisterClass)
BuildMI(MBB, I, DL, get(Mips::MOVCCRToCCR), DestReg).addReg(SrcReg);
else
// Can't copy this register
return false;
return true;
}
void MipsInstrInfo::
storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned SrcReg, bool isKill, int FI,
const TargetRegisterClass *RC) const {
unsigned Opc;
DebugLoc DL = DebugLoc::getUnknownLoc();
if (I != MBB.end()) DL = I->getDebugLoc();
if (RC == Mips::CPURegsRegisterClass)
Opc = Mips::SW;
else if (RC == Mips::FGR32RegisterClass)
Opc = Mips::SWC1;
else {
assert(RC == Mips::AFGR64RegisterClass);
Opc = Mips::SDC1;
}
BuildMI(MBB, I, DL, get(Opc)).addReg(SrcReg, getKillRegState(isKill))
.addImm(0).addFrameIndex(FI);
}
void MipsInstrInfo::storeRegToAddr(MachineFunction &MF, unsigned SrcReg,
bool isKill, SmallVectorImpl<MachineOperand> &Addr,
const TargetRegisterClass *RC, SmallVectorImpl<MachineInstr*> &NewMIs) const
{
unsigned Opc;
if (RC == Mips::CPURegsRegisterClass)
Opc = Mips::SW;
else if (RC == Mips::FGR32RegisterClass)
Opc = Mips::SWC1;
else {
assert(RC == Mips::AFGR64RegisterClass);
Opc = Mips::SDC1;
}
DebugLoc DL = DebugLoc::getUnknownLoc();
MachineInstrBuilder MIB = BuildMI(MF, DL, get(Opc))
.addReg(SrcReg, getKillRegState(isKill));
for (unsigned i = 0, e = Addr.size(); i != e; ++i)
MIB.addOperand(Addr[i]);
NewMIs.push_back(MIB);
return;
}
void MipsInstrInfo::
loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned DestReg, int FI,
const TargetRegisterClass *RC) const
{
unsigned Opc;
if (RC == Mips::CPURegsRegisterClass)
Opc = Mips::LW;
else if (RC == Mips::FGR32RegisterClass)
Opc = Mips::LWC1;
else {
assert(RC == Mips::AFGR64RegisterClass);
Opc = Mips::LDC1;
}
DebugLoc DL = DebugLoc::getUnknownLoc();
if (I != MBB.end()) DL = I->getDebugLoc();
BuildMI(MBB, I, DL, get(Opc), DestReg).addImm(0).addFrameIndex(FI);
}
void MipsInstrInfo::loadRegFromAddr(MachineFunction &MF, unsigned DestReg,
SmallVectorImpl<MachineOperand> &Addr,
const TargetRegisterClass *RC,
SmallVectorImpl<MachineInstr*> &NewMIs) const {
unsigned Opc;
if (RC == Mips::CPURegsRegisterClass)
Opc = Mips::LW;
else if (RC == Mips::FGR32RegisterClass)
Opc = Mips::LWC1;
else {
assert(RC == Mips::AFGR64RegisterClass);
Opc = Mips::LDC1;
}
DebugLoc DL = DebugLoc::getUnknownLoc();
MachineInstrBuilder MIB = BuildMI(MF, DL, get(Opc), DestReg);
for (unsigned i = 0, e = Addr.size(); i != e; ++i)
MIB.addOperand(Addr[i]);
NewMIs.push_back(MIB);
return;
}
MachineInstr *MipsInstrInfo::
foldMemoryOperandImpl(MachineFunction &MF,
MachineInstr* MI,
const SmallVectorImpl<unsigned> &Ops, int FI) const
{
if (Ops.size() != 1) return NULL;
MachineInstr *NewMI = NULL;
switch (MI->getOpcode()) {
case Mips::ADDu:
if ((MI->getOperand(0).isReg()) &&
(MI->getOperand(1).isReg()) &&
(MI->getOperand(1).getReg() == Mips::ZERO) &&
(MI->getOperand(2).isReg())) {
if (Ops[0] == 0) { // COPY -> STORE
unsigned SrcReg = MI->getOperand(2).getReg();
bool isKill = MI->getOperand(2).isKill();
NewMI = BuildMI(MF, MI->getDebugLoc(), get(Mips::SW))
.addReg(SrcReg, getKillRegState(isKill))
.addImm(0).addFrameIndex(FI);
} else { // COPY -> LOAD
unsigned DstReg = MI->getOperand(0).getReg();
bool isDead = MI->getOperand(0).isDead();
NewMI = BuildMI(MF, MI->getDebugLoc(), get(Mips::LW))
.addReg(DstReg, RegState::Define | getDeadRegState(isDead))
.addImm(0).addFrameIndex(FI);
}
}
break;
case Mips::FMOV_S32:
case Mips::FMOV_D32:
if ((MI->getOperand(0).isReg()) &&
(MI->getOperand(1).isReg())) {
const TargetRegisterClass
*RC = RI.getRegClass(MI->getOperand(0).getReg());
unsigned StoreOpc, LoadOpc;
if (RC == Mips::FGR32RegisterClass) {
LoadOpc = Mips::LWC1; StoreOpc = Mips::SWC1;
} else {
assert(RC == Mips::AFGR64RegisterClass);
LoadOpc = Mips::LDC1; StoreOpc = Mips::SDC1;
}
if (Ops[0] == 0) { // COPY -> STORE
unsigned SrcReg = MI->getOperand(1).getReg();
bool isKill = MI->getOperand(1).isKill();
NewMI = BuildMI(MF, MI->getDebugLoc(), get(StoreOpc))
.addReg(SrcReg, getKillRegState(isKill))
.addImm(0).addFrameIndex(FI) ;
} else { // COPY -> LOAD
unsigned DstReg = MI->getOperand(0).getReg();
bool isDead = MI->getOperand(0).isDead();
NewMI = BuildMI(MF, MI->getDebugLoc(), get(LoadOpc))
.addReg(DstReg, RegState::Define | getDeadRegState(isDead))
.addImm(0).addFrameIndex(FI);
}
}
break;
}
return NewMI;
}
//===----------------------------------------------------------------------===//
// Branch Analysis
//===----------------------------------------------------------------------===//
/// GetCondFromBranchOpc - Return the Mips CC that matches
/// the correspondent Branch instruction opcode.
static Mips::CondCode GetCondFromBranchOpc(unsigned BrOpc)
{
switch (BrOpc) {
default: return Mips::COND_INVALID;
case Mips::BEQ : return Mips::COND_E;
case Mips::BNE : return Mips::COND_NE;
case Mips::BGTZ : return Mips::COND_GZ;
case Mips::BGEZ : return Mips::COND_GEZ;
case Mips::BLTZ : return Mips::COND_LZ;
case Mips::BLEZ : return Mips::COND_LEZ;
// We dont do fp branch analysis yet!
case Mips::BC1T :
case Mips::BC1F : return Mips::COND_INVALID;
}
}
/// GetCondBranchFromCond - Return the Branch instruction
/// opcode that matches the cc.
unsigned Mips::GetCondBranchFromCond(Mips::CondCode CC)
{
switch (CC) {
default: assert(0 && "Illegal condition code!");
case Mips::COND_E : return Mips::BEQ;
case Mips::COND_NE : return Mips::BNE;
case Mips::COND_GZ : return Mips::BGTZ;
case Mips::COND_GEZ : return Mips::BGEZ;
case Mips::COND_LZ : return Mips::BLTZ;
case Mips::COND_LEZ : return Mips::BLEZ;
case Mips::FCOND_F:
case Mips::FCOND_UN:
case Mips::FCOND_EQ:
case Mips::FCOND_UEQ:
case Mips::FCOND_OLT:
case Mips::FCOND_ULT:
case Mips::FCOND_OLE:
case Mips::FCOND_ULE:
case Mips::FCOND_SF:
case Mips::FCOND_NGLE:
case Mips::FCOND_SEQ:
case Mips::FCOND_NGL:
case Mips::FCOND_LT:
case Mips::FCOND_NGE:
case Mips::FCOND_LE:
case Mips::FCOND_NGT: return Mips::BC1T;
case Mips::FCOND_T:
case Mips::FCOND_OR:
case Mips::FCOND_NEQ:
case Mips::FCOND_OGL:
case Mips::FCOND_UGE:
case Mips::FCOND_OGE:
case Mips::FCOND_UGT:
case Mips::FCOND_OGT:
case Mips::FCOND_ST:
case Mips::FCOND_GLE:
case Mips::FCOND_SNE:
case Mips::FCOND_GL:
case Mips::FCOND_NLT:
case Mips::FCOND_GE:
case Mips::FCOND_NLE:
case Mips::FCOND_GT: return Mips::BC1F;
}
}
/// GetOppositeBranchCondition - Return the inverse of the specified
/// condition, e.g. turning COND_E to COND_NE.
Mips::CondCode Mips::GetOppositeBranchCondition(Mips::CondCode CC)
{
switch (CC) {
default: assert(0 && "Illegal condition code!");
case Mips::COND_E : return Mips::COND_NE;
case Mips::COND_NE : return Mips::COND_E;
case Mips::COND_GZ : return Mips::COND_LEZ;
case Mips::COND_GEZ : return Mips::COND_LZ;
case Mips::COND_LZ : return Mips::COND_GEZ;
case Mips::COND_LEZ : return Mips::COND_GZ;
case Mips::FCOND_F : return Mips::FCOND_T;
case Mips::FCOND_UN : return Mips::FCOND_OR;
case Mips::FCOND_EQ : return Mips::FCOND_NEQ;
case Mips::FCOND_UEQ: return Mips::FCOND_OGL;
case Mips::FCOND_OLT: return Mips::FCOND_UGE;
case Mips::FCOND_ULT: return Mips::FCOND_OGE;
case Mips::FCOND_OLE: return Mips::FCOND_UGT;
case Mips::FCOND_ULE: return Mips::FCOND_OGT;
case Mips::FCOND_SF: return Mips::FCOND_ST;
case Mips::FCOND_NGLE:return Mips::FCOND_GLE;
case Mips::FCOND_SEQ: return Mips::FCOND_SNE;
case Mips::FCOND_NGL: return Mips::FCOND_GL;
case Mips::FCOND_LT: return Mips::FCOND_NLT;
case Mips::FCOND_NGE: return Mips::FCOND_GE;
case Mips::FCOND_LE: return Mips::FCOND_NLE;
case Mips::FCOND_NGT: return Mips::FCOND_GT;
}
}
bool MipsInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,
MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify) const
{
// If the block has no terminators, it just falls into the block after it.
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin() || !isUnpredicatedTerminator(--I))
return false;
// Get the last instruction in the block.
MachineInstr *LastInst = I;
// If there is only one terminator instruction, process it.
unsigned LastOpc = LastInst->getOpcode();
if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
if (!LastInst->getDesc().isBranch())
return true;
// Unconditional branch
if (LastOpc == Mips::J) {
TBB = LastInst->getOperand(0).getMBB();
return false;
}
Mips::CondCode BranchCode = GetCondFromBranchOpc(LastInst->getOpcode());
if (BranchCode == Mips::COND_INVALID)
return true; // Can't handle indirect branch.
// Conditional branch
// Block ends with fall-through condbranch.
if (LastOpc != Mips::COND_INVALID) {
int LastNumOp = LastInst->getNumOperands();
TBB = LastInst->getOperand(LastNumOp-1).getMBB();
Cond.push_back(MachineOperand::CreateImm(BranchCode));
for (int i=0; i<LastNumOp-1; i++) {
Cond.push_back(LastInst->getOperand(i));
}
return false;
}
}
// Get the instruction before it if it is a terminator.
MachineInstr *SecondLastInst = I;
// If there are three terminators, we don't know what sort of block this is.
if (SecondLastInst && I != MBB.begin() && isUnpredicatedTerminator(--I))
return true;
// If the block ends with Mips::J and a Mips::BNE/Mips::BEQ, handle it.
unsigned SecondLastOpc = SecondLastInst->getOpcode();
Mips::CondCode BranchCode = GetCondFromBranchOpc(SecondLastOpc);
if (BranchCode != Mips::COND_INVALID && LastOpc == Mips::J) {
int SecondNumOp = SecondLastInst->getNumOperands();
TBB = SecondLastInst->getOperand(SecondNumOp-1).getMBB();
Cond.push_back(MachineOperand::CreateImm(BranchCode));
for (int i=0; i<SecondNumOp-1; i++) {
Cond.push_back(SecondLastInst->getOperand(i));
}
FBB = LastInst->getOperand(0).getMBB();
return false;
}
// If the block ends with two unconditional branches, handle it. The last
// one is not executed, so remove it.
if ((SecondLastOpc == Mips::J) && (LastOpc == Mips::J)) {
TBB = SecondLastInst->getOperand(0).getMBB();
I = LastInst;
if (AllowModify)
I->eraseFromParent();
return false;
}
// Otherwise, can't handle this.
return true;
}
unsigned MipsInstrInfo::
InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond) const {
// FIXME this should probably have a DebugLoc argument
DebugLoc dl = DebugLoc::getUnknownLoc();
// Shouldn't be a fall through.
assert(TBB && "InsertBranch must not be told to insert a fallthrough");
assert((Cond.size() == 3 || Cond.size() == 2 || Cond.size() == 0) &&
"Mips branch conditions can have two|three components!");
if (FBB == 0) { // One way branch.
if (Cond.empty()) {
// Unconditional branch?
BuildMI(&MBB, dl, get(Mips::J)).addMBB(TBB);
} else {
// Conditional branch.
unsigned Opc = GetCondBranchFromCond((Mips::CondCode)Cond[0].getImm());
const TargetInstrDesc &TID = get(Opc);
if (TID.getNumOperands() == 3)
BuildMI(&MBB, dl, TID).addReg(Cond[1].getReg())
.addReg(Cond[2].getReg())
.addMBB(TBB);
else
BuildMI(&MBB, dl, TID).addReg(Cond[1].getReg())
.addMBB(TBB);
}
return 1;
}
// Two-way Conditional branch.
unsigned Opc = GetCondBranchFromCond((Mips::CondCode)Cond[0].getImm());
const TargetInstrDesc &TID = get(Opc);
if (TID.getNumOperands() == 3)
BuildMI(&MBB, dl, TID).addReg(Cond[1].getReg()).addReg(Cond[2].getReg())
.addMBB(TBB);
else
BuildMI(&MBB, dl, TID).addReg(Cond[1].getReg()).addMBB(TBB);
BuildMI(&MBB, dl, get(Mips::J)).addMBB(FBB);
return 2;
}
unsigned MipsInstrInfo::
RemoveBranch(MachineBasicBlock &MBB) const
{
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin()) return 0;
--I;
if (I->getOpcode() != Mips::J &&
GetCondFromBranchOpc(I->getOpcode()) == Mips::COND_INVALID)
return 0;
// Remove the branch.
I->eraseFromParent();
I = MBB.end();
if (I == MBB.begin()) return 1;
--I;
if (GetCondFromBranchOpc(I->getOpcode()) == Mips::COND_INVALID)
return 1;
// Remove the branch.
I->eraseFromParent();
return 2;
}
/// BlockHasNoFallThrough - Analyze if MachineBasicBlock does not
/// fall-through into its successor block.
bool MipsInstrInfo::
BlockHasNoFallThrough(const MachineBasicBlock &MBB) const
{
if (MBB.empty()) return false;
switch (MBB.back().getOpcode()) {
case Mips::RET: // Return.
case Mips::JR: // Indirect branch.
case Mips::J: // Uncond branch.
return true;
default: return false;
}
}
/// ReverseBranchCondition - Return the inverse opcode of the
/// specified Branch instruction.
bool MipsInstrInfo::
ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const
{
assert( (Cond.size() == 3 || Cond.size() == 2) &&
"Invalid Mips branch condition!");
Cond[0].setImm(GetOppositeBranchCondition((Mips::CondCode)Cond[0].getImm()));
return false;
}
/// getGlobalBaseReg - Return a virtual register initialized with the
/// the global base register value. Output instructions required to
/// initialize the register in the function entry block, if necessary.
///
unsigned MipsInstrInfo::getGlobalBaseReg(MachineFunction *MF) const {
MipsFunctionInfo *MipsFI = MF->getInfo<MipsFunctionInfo>();
unsigned GlobalBaseReg = MipsFI->getGlobalBaseReg();
if (GlobalBaseReg != 0)
return GlobalBaseReg;
// Insert the set of GlobalBaseReg into the first MBB of the function
MachineBasicBlock &FirstMBB = MF->front();
MachineBasicBlock::iterator MBBI = FirstMBB.begin();
MachineRegisterInfo &RegInfo = MF->getRegInfo();
const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
GlobalBaseReg = RegInfo.createVirtualRegister(Mips::CPURegsRegisterClass);
bool Ok = TII->copyRegToReg(FirstMBB, MBBI, GlobalBaseReg, Mips::GP,
Mips::CPURegsRegisterClass,
Mips::CPURegsRegisterClass);
assert(Ok && "Couldn't assign to global base register!");
RegInfo.addLiveIn(Mips::GP);
MipsFI->setGlobalBaseReg(GlobalBaseReg);
return GlobalBaseReg;
}