-static unsigned createLaneVGPR(MachineRegisterInfo &MRI, MachineFunction *MF) {
- unsigned VGPR = MRI.createVirtualRegister(&AMDGPU::VReg_32RegClass);
-
- // We need to add this register as live out for the function, in order to
- // have the live range calculated directly.
- //
- // When register spilling begins, we have already calculated the live
- // live intervals for all the registers. Since we are spilling SGPRs to
- // VGPRs, we need to update the Lane VGPR's live interval every time we
- // spill or restore a register.
- //
- // Unfortunately, there is no good way to update the live interval as
- // the TargetInstrInfo callbacks for spilling and restoring don't give
- // us access to the live interval information.
- //
- // We are lucky, though, because the InlineSpiller calls
- // LiveRangeEdit::calculateRegClassAndHint() which iterates through
- // all the new register that have been created when restoring a register
- // and calls LiveIntervals::getInterval(), which creates and computes
- // the live interval for the newly created register. However, once this
- // live intervals is created, it doesn't change and since we usually reuse
- // the Lane VGPR multiple times, this means any uses after the first aren't
- // added to the live interval.
- //
- // To work around this, we add Lane VGPRs to the functions live out list,
- // so that we can guarantee its live range will cover all of its uses.
-
- for (MachineBasicBlock &MBB : *MF) {
- if (MBB.back().getOpcode() == AMDGPU::S_ENDPGM) {
- MBB.back().addOperand(*MF, MachineOperand::CreateReg(VGPR, false, true));
- return VGPR;
- }
- }
-
- LLVMContext &Ctx = MF->getFunction()->getContext();
- Ctx.emitError("Could not find S_ENDPGM instruction.");
-
- return VGPR;
-}
-
-unsigned SIMachineFunctionInfo::RegSpillTracker::reserveLanes(
- MachineRegisterInfo &MRI, MachineFunction *MF, unsigned NumRegs) {
- unsigned StartLane = CurrentLane;
- CurrentLane += NumRegs;
- if (!LaneVGPR) {
- LaneVGPR = createLaneVGPR(MRI, MF);
- } else {
- if (CurrentLane >= MAX_LANES) {
- StartLane = CurrentLane = 0;
- LaneVGPR = createLaneVGPR(MRI, MF);
- }
- }
- return StartLane;
-}
-
-void SIMachineFunctionInfo::RegSpillTracker::addSpilledReg(unsigned FrameIndex,
- unsigned Reg,
- int Lane) {
- SpilledRegisters[FrameIndex] = SpilledReg(Reg, Lane);
-}