/// Generate a predicated version of MI (where the condition is given via
/// PredR and Cond) at the point indicated by Where.
void HexagonExpandCondsets::predicateAt(const MachineOperand &DefOp,
MachineInstr &MI,
MachineBasicBlock::iterator Where,
const MachineOperand &PredOp, bool Cond,
std::set<unsigned> &UpdRegs) {
// The problem with updating live intervals is that we can move one def
// past another def. In particular, this can happen when moving an A2_tfrt
// over an A2_tfrf defining the same register. From the point of view of
// live intervals, these two instructions are two separate definitions,
// and each one starts another live segment. LiveIntervals's "handleMove"
// does not allow such moves, so we need to handle it ourselves. To avoid
// invalidating liveness data while we are using it, the move will be
// implemented in 4 steps: (1) add a clone of the instruction MI at the
// target location, (2) update liveness, (3) delete the old instruction,
// and (4) update liveness again.
MachineBasicBlock &B = *MI.getParent();
DebugLoc DL = Where->getDebugLoc(); // "Where" points to an instruction.
unsigned Opc = MI.getOpcode();
unsigned PredOpc = HII->getCondOpcode(Opc, !Cond);
MachineInstrBuilder MB = BuildMI(B, Where, DL, HII->get(PredOpc));
unsigned Ox = 0, NP = MI.getNumOperands();
// Skip all defs from MI first.
while (Ox < NP) {
MachineOperand &MO = MI.getOperand(Ox);
if (!MO.isReg() || !MO.isDef())
break;
Ox++;
}
// Add the new def, then the predicate register, then the rest of the
// operands.
MB.addReg(DefOp.getReg(), getRegState(DefOp), DefOp.getSubReg());
MB.addReg(PredOp.getReg(), PredOp.isUndef() ? RegState::Undef : 0,
PredOp.getSubReg());
while (Ox < NP) {
MachineOperand &MO = MI.getOperand(Ox);
if (!MO.isReg() || !MO.isImplicit())
MB.add(MO);
Ox++;
}
MachineFunction &MF = *B.getParent();
MachineInstr::mmo_iterator I = MI.memoperands_begin();
unsigned NR = std::distance(I, MI.memoperands_end());
MachineInstr::mmo_iterator MemRefs = MF.allocateMemRefsArray(NR);
for (unsigned i = 0; i < NR; ++i)
MemRefs[i] = *I++;
MB.setMemRefs(MemRefs, MemRefs+NR);
MachineInstr *NewI = MB;
NewI->clearKillInfo();
LIS->InsertMachineInstrInMaps(*NewI);
for (auto &Op : NewI->operands())
if (Op.isReg())
UpdRegs.insert(Op.getReg());
}
void Liveness::resetKills(MachineBasicBlock *B) {
auto CopyLiveIns = [] (MachineBasicBlock *B, BitVector &LV) -> void {
for (auto I = B->livein_begin(), E = B->livein_end(); I != E; ++I)
LV.set(I->PhysReg);
};
BitVector LiveIn(TRI.getNumRegs()), Live(TRI.getNumRegs());
CopyLiveIns(B, LiveIn);
for (auto SI : B->successors())
CopyLiveIns(SI, Live);
for (auto I = B->rbegin(), E = B->rend(); I != E; ++I) {
MachineInstr *MI = &*I;
if (MI->isDebugValue())
continue;
MI->clearKillInfo();
for (auto &Op : MI->operands()) {
// An implicit def of a super-register may not necessarily start a
// live range of it, since an implicit use could be used to keep parts
// of it live. Instead of analyzing the implicit operands, ignore
// implicit defs.
if (!Op.isReg() || !Op.isDef() || Op.isImplicit())
continue;
unsigned R = Op.getReg();
if (!TargetRegisterInfo::isPhysicalRegister(R))
continue;
for (MCSubRegIterator SR(R, &TRI, true); SR.isValid(); ++SR)
Live.reset(*SR);
}
for (auto &Op : MI->operands()) {
if (!Op.isReg() || !Op.isUse())
continue;
unsigned R = Op.getReg();
if (!TargetRegisterInfo::isPhysicalRegister(R))
continue;
bool IsLive = false;
for (MCRegAliasIterator AR(R, &TRI, true); AR.isValid(); ++AR) {
if (!Live[*AR])
continue;
IsLive = true;
break;
}
if (IsLive)
continue;
Op.setIsKill(true);
for (MCSubRegIterator SR(R, &TRI, true); SR.isValid(); ++SR)
Live.set(*SR);
}
}
}
void Liveness::resetKills(MachineBasicBlock *B) {
auto CopyLiveIns = [] (MachineBasicBlock *B, BitVector &LV) -> void {
for (auto I = B->livein_begin(), E = B->livein_end(); I != E; ++I)
LV.set(I->PhysReg);
};
BitVector LiveIn(TRI.getNumRegs()), Live(TRI.getNumRegs());
CopyLiveIns(B, LiveIn);
for (auto SI : B->successors())
CopyLiveIns(SI, Live);
for (auto I = B->rbegin(), E = B->rend(); I != E; ++I) {
MachineInstr *MI = &*I;
if (MI->isDebugValue())
continue;
MI->clearKillInfo();
for (auto &Op : MI->operands()) {
if (!Op.isReg() || !Op.isDef())
continue;
unsigned R = Op.getReg();
if (!TargetRegisterInfo::isPhysicalRegister(R))
continue;
for (MCSubRegIterator SR(R, &TRI, true); SR.isValid(); ++SR)
Live.reset(*SR);
}
for (auto &Op : MI->operands()) {
if (!Op.isReg() || !Op.isUse())
continue;
unsigned R = Op.getReg();
if (!TargetRegisterInfo::isPhysicalRegister(R))
continue;
bool IsLive = false;
for (MCRegAliasIterator AR(R, &TRI, true); AR.isValid(); ++AR) {
if (!Live[*AR])
continue;
IsLive = true;
break;
}
if (IsLive)
continue;
Op.setIsKill(true);
for (MCSubRegIterator SR(R, &TRI, true); SR.isValid(); ++SR)
Live.set(*SR);
}
}
}
/// Generate a conditional transfer, copying the value SrcOp to the
/// destination register DstR:DstSR, and using the predicate register from
/// PredOp. The Cond argument specifies whether the predicate is to be
/// if(PredOp), or if(!PredOp).
MachineInstr *HexagonExpandCondsets::genTfrFor(MachineOperand &SrcOp,
unsigned DstR, unsigned DstSR, const MachineOperand &PredOp, bool Cond) {
MachineInstr *MI = SrcOp.getParent();
MachineBasicBlock &B = *MI->getParent();
MachineBasicBlock::iterator At = MI;
DebugLoc DL = MI->getDebugLoc();
// Don't avoid identity copies here (i.e. if the source and the destination
// are the same registers). It is actually better to generate them here,
// since this would cause the copy to potentially be predicated in the next
// step. The predication will remove such a copy if it is unable to
/// predicate.
unsigned Opc = getCondTfrOpcode(SrcOp, Cond);
MachineInstr *TfrI = BuildMI(B, At, DL, HII->get(Opc))
.addReg(DstR, RegState::Define, DstSR)
.addOperand(PredOp)
.addOperand(SrcOp);
// We don't want any kills yet.
TfrI->clearKillInfo();
DEBUG(dbgs() << "created an initial copy: " << *TfrI);
return TfrI;
}