static void createDeadDef(SlotIndexes &Indexes, VNInfo::Allocator &Alloc,
LiveRange &LR, const MachineOperand &MO) {
const MachineInstr &MI = *MO.getParent();
SlotIndex DefIdx =
Indexes.getInstructionIndex(MI).getRegSlot(MO.isEarlyClobber());
// Create the def in LR. This may find an existing def.
LR.createDeadDef(DefIdx, Alloc);
}
/// computeLiveInRegUnits - Precompute the live ranges of any register units
/// that are live-in to an ABI block somewhere. Register values can appear
/// without a corresponding def when entering the entry block or a landing pad.
///
void LiveIntervals::computeLiveInRegUnits() {
RegUnitRanges.resize(TRI->getNumRegUnits());
DEBUG(dbgs() << "Computing live-in reg-units in ABI blocks.\n");
// Keep track of the live range sets allocated.
SmallVector<unsigned, 8> NewRanges;
// Check all basic blocks for live-ins.
for (MachineFunction::const_iterator MFI = MF->begin(), MFE = MF->end();
MFI != MFE; ++MFI) {
const MachineBasicBlock *MBB = MFI;
// We only care about ABI blocks: Entry + landing pads.
if ((MFI != MF->begin() && !MBB->isLandingPad()) || MBB->livein_empty())
continue;
// Create phi-defs at Begin for all live-in registers.
SlotIndex Begin = Indexes->getMBBStartIdx(MBB);
DEBUG(dbgs() << Begin << "\tBB#" << MBB->getNumber());
for (MachineBasicBlock::livein_iterator LII = MBB->livein_begin(),
LIE = MBB->livein_end(); LII != LIE; ++LII) {
for (MCRegUnitIterator Units(*LII, TRI); Units.isValid(); ++Units) {
unsigned Unit = *Units;
LiveRange *LR = RegUnitRanges[Unit];
if (!LR) {
LR = RegUnitRanges[Unit] = new LiveRange();
NewRanges.push_back(Unit);
}
VNInfo *VNI = LR->createDeadDef(Begin, getVNInfoAllocator());
(void)VNI;
DEBUG(dbgs() << ' ' << PrintRegUnit(Unit, TRI) << '#' << VNI->id);
}
}
DEBUG(dbgs() << '\n');
}
DEBUG(dbgs() << "Created " << NewRanges.size() << " new intervals.\n");
// Compute the 'normal' part of the ranges.
for (unsigned i = 0, e = NewRanges.size(); i != e; ++i) {
unsigned Unit = NewRanges[i];
computeRegUnitRange(*RegUnitRanges[Unit], Unit);
}
}
void LiveRangeCalc::createDeadDefs(LiveRange &LR, unsigned Reg) {
assert(MRI && Indexes && "call reset() first");
// Visit all def operands. If the same instruction has multiple defs of Reg,
// LR.createDeadDef() will deduplicate.
for (MachineOperand &MO : MRI->def_operands(Reg)) {
const MachineInstr *MI = MO.getParent();
// Find the corresponding slot index.
SlotIndex Idx;
if (MI->isPHI())
// PHI defs begin at the basic block start index.
Idx = Indexes->getMBBStartIdx(MI->getParent());
else
// Instructions are either normal 'r', or early clobber 'e'.
Idx = Indexes->getInstructionIndex(MI)
.getRegSlot(MO.isEarlyClobber());
// Create the def in LR. This may find an existing def.
LR.createDeadDef(Idx, *Alloc);
}
}