MachineInstr *
LanaiInstrInfo::optimizeSelect(MachineInstr &MI,
SmallPtrSetImpl<MachineInstr *> &SeenMIs,
bool PreferFalse) const {
assert(MI.getOpcode() == Lanai::SELECT && "unknown select instruction");
MachineRegisterInfo &MRI = MI.getParent()->getParent()->getRegInfo();
MachineInstr *DefMI = canFoldIntoSelect(MI.getOperand(1).getReg(), MRI, this);
bool Invert = !DefMI;
if (!DefMI)
DefMI = canFoldIntoSelect(MI.getOperand(2).getReg(), MRI, this);
if (!DefMI)
return nullptr;
// Find new register class to use.
MachineOperand FalseReg = MI.getOperand(Invert ? 1 : 2);
unsigned DestReg = MI.getOperand(0).getReg();
const TargetRegisterClass *PreviousClass = MRI.getRegClass(FalseReg.getReg());
if (!MRI.constrainRegClass(DestReg, PreviousClass))
return nullptr;
// Create a new predicated version of DefMI.
MachineInstrBuilder NewMI =
BuildMI(*MI.getParent(), MI, MI.getDebugLoc(), DefMI->getDesc(), DestReg);
// Copy all the DefMI operands, excluding its (null) predicate.
const MCInstrDesc &DefDesc = DefMI->getDesc();
for (unsigned i = 1, e = DefDesc.getNumOperands();
i != e && !DefDesc.OpInfo[i].isPredicate(); ++i)
NewMI.addOperand(DefMI->getOperand(i));
unsigned CondCode = MI.getOperand(3).getImm();
if (Invert)
NewMI.addImm(getOppositeCondition(LPCC::CondCode(CondCode)));
else
NewMI.addImm(CondCode);
NewMI.copyImplicitOps(MI);
// The output register value when the predicate is false is an implicit
// register operand tied to the first def. The tie makes the register
// allocator ensure the FalseReg is allocated the same register as operand 0.
FalseReg.setImplicit();
NewMI.addOperand(FalseReg);
NewMI->tieOperands(0, NewMI->getNumOperands() - 1);
// Update SeenMIs set: register newly created MI and erase removed DefMI.
SeenMIs.insert(NewMI);
SeenMIs.erase(DefMI);
// If MI is inside a loop, and DefMI is outside the loop, then kill flags on
// DefMI would be invalid when transferred inside the loop. Checking for a
// loop is expensive, but at least remove kill flags if they are in different
// BBs.
if (DefMI->getParent() != MI.getParent())
NewMI->clearKillInfo();
// The caller will erase MI, but not DefMI.
DefMI->eraseFromParent();
return NewMI;
}
/// ExpandVLD - Translate VLD pseudo instructions with Q, QQ or QQQQ register
/// operands to real VLD instructions with D register operands.
void ARMExpandPseudo::ExpandVLD(MachineBasicBlock::iterator &MBBI) {
MachineInstr &MI = *MBBI;
MachineBasicBlock &MBB = *MI.getParent();
const NEONLdStTableEntry *TableEntry = LookupNEONLdSt(MI.getOpcode());
assert(TableEntry && TableEntry->IsLoad && "NEONLdStTable lookup failed");
NEONRegSpacing RegSpc = TableEntry->RegSpacing;
unsigned NumRegs = TableEntry->NumRegs;
MachineInstrBuilder MIB = BuildMI(MBB, MBBI, MI.getDebugLoc(),
TII->get(TableEntry->RealOpc));
unsigned OpIdx = 0;
bool DstIsDead = MI.getOperand(OpIdx).isDead();
unsigned DstReg = MI.getOperand(OpIdx++).getReg();
unsigned D0, D1, D2, D3;
GetDSubRegs(DstReg, RegSpc, TRI, D0, D1, D2, D3);
MIB.addReg(D0, RegState::Define | getDeadRegState(DstIsDead))
.addReg(D1, RegState::Define | getDeadRegState(DstIsDead));
if (NumRegs > 2)
MIB.addReg(D2, RegState::Define | getDeadRegState(DstIsDead));
if (NumRegs > 3)
MIB.addReg(D3, RegState::Define | getDeadRegState(DstIsDead));
if (TableEntry->HasWriteBack)
MIB.addOperand(MI.getOperand(OpIdx++));
// Copy the addrmode6 operands.
MIB.addOperand(MI.getOperand(OpIdx++));
MIB.addOperand(MI.getOperand(OpIdx++));
// Copy the am6offset operand.
if (TableEntry->HasWriteBack)
MIB.addOperand(MI.getOperand(OpIdx++));
// For an instruction writing double-spaced subregs, the pseudo instruction
// has an extra operand that is a use of the super-register. Record the
// operand index and skip over it.
unsigned SrcOpIdx = 0;
if (RegSpc == EvenDblSpc || RegSpc == OddDblSpc)
SrcOpIdx = OpIdx++;
// Copy the predicate operands.
MIB.addOperand(MI.getOperand(OpIdx++));
MIB.addOperand(MI.getOperand(OpIdx++));
// Copy the super-register source operand used for double-spaced subregs over
// to the new instruction as an implicit operand.
if (SrcOpIdx != 0) {
MachineOperand MO = MI.getOperand(SrcOpIdx);
MO.setImplicit(true);
MIB.addOperand(MO);
}
// Add an implicit def for the super-register.
MIB.addReg(DstReg, RegState::ImplicitDefine | getDeadRegState(DstIsDead));
TransferImpOps(MI, MIB, MIB);
MI.eraseFromParent();
}
/// ExpandLaneOp - Translate VLD*LN and VST*LN instructions with Q, QQ or QQQQ
/// register operands to real instructions with D register operands.
void ARMExpandPseudo::ExpandLaneOp(MachineBasicBlock::iterator &MBBI) {
MachineInstr &MI = *MBBI;
MachineBasicBlock &MBB = *MI.getParent();
const NEONLdStTableEntry *TableEntry = LookupNEONLdSt(MI.getOpcode());
assert(TableEntry && "NEONLdStTable lookup failed");
NEONRegSpacing RegSpc = TableEntry->RegSpacing;
unsigned NumRegs = TableEntry->NumRegs;
unsigned RegElts = TableEntry->RegElts;
MachineInstrBuilder MIB = BuildMI(MBB, MBBI, MI.getDebugLoc(),
TII->get(TableEntry->RealOpc));
unsigned OpIdx = 0;
// The lane operand is always the 3rd from last operand, before the 2
// predicate operands.
unsigned Lane = MI.getOperand(MI.getDesc().getNumOperands() - 3).getImm();
// Adjust the lane and spacing as needed for Q registers.
assert(RegSpc != OddDblSpc && "unexpected register spacing for VLD/VST-lane");
if (RegSpc == EvenDblSpc && Lane >= RegElts) {
RegSpc = OddDblSpc;
Lane -= RegElts;
}
assert(Lane < RegElts && "out of range lane for VLD/VST-lane");
unsigned D0, D1, D2, D3;
unsigned DstReg = 0;
bool DstIsDead = false;
if (TableEntry->IsLoad) {
DstIsDead = MI.getOperand(OpIdx).isDead();
DstReg = MI.getOperand(OpIdx++).getReg();
GetDSubRegs(DstReg, RegSpc, TRI, D0, D1, D2, D3);
MIB.addReg(D0, RegState::Define | getDeadRegState(DstIsDead))
.addReg(D1, RegState::Define | getDeadRegState(DstIsDead));
if (NumRegs > 2)
MIB.addReg(D2, RegState::Define | getDeadRegState(DstIsDead));
if (NumRegs > 3)
MIB.addReg(D3, RegState::Define | getDeadRegState(DstIsDead));
}
if (TableEntry->HasWriteBack)
MIB.addOperand(MI.getOperand(OpIdx++));
// Copy the addrmode6 operands.
MIB.addOperand(MI.getOperand(OpIdx++));
MIB.addOperand(MI.getOperand(OpIdx++));
// Copy the am6offset operand.
if (TableEntry->HasWriteBack)
MIB.addOperand(MI.getOperand(OpIdx++));
// Grab the super-register source.
MachineOperand MO = MI.getOperand(OpIdx++);
if (!TableEntry->IsLoad)
GetDSubRegs(MO.getReg(), RegSpc, TRI, D0, D1, D2, D3);
// Add the subregs as sources of the new instruction.
unsigned SrcFlags = (getUndefRegState(MO.isUndef()) |
getKillRegState(MO.isKill()));
MIB.addReg(D0, SrcFlags).addReg(D1, SrcFlags);
if (NumRegs > 2)
MIB.addReg(D2, SrcFlags);
if (NumRegs > 3)
MIB.addReg(D3, SrcFlags);
// Add the lane number operand.
MIB.addImm(Lane);
OpIdx += 1;
// Copy the predicate operands.
MIB.addOperand(MI.getOperand(OpIdx++));
MIB.addOperand(MI.getOperand(OpIdx++));
// Copy the super-register source to be an implicit source.
MO.setImplicit(true);
MIB.addOperand(MO);
if (TableEntry->IsLoad)
// Add an implicit def for the super-register.
MIB.addReg(DstReg, RegState::ImplicitDefine | getDeadRegState(DstIsDead));
TransferImpOps(MI, MIB, MIB);
MI.eraseFromParent();
}