SIMachineFunctionInfo::SIMachineFunctionInfo(const MachineFunction &MF)
: AMDGPUMachineFunction(MF),
PSInputAddr(0),
- SpillTracker(),
NumUserSGPRs(0) { }
-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);
-}
/// \brief Returns a register that is not used at any point in the function.
/// If all registers are used, then this function will return
// AMDGPU::NoRegister.
bool hasLane() { return Lane != -1;}
};
- struct RegSpillTracker {
- private:
- unsigned CurrentLane;
- std::map<unsigned, SpilledReg> SpilledRegisters;
- public:
- unsigned LaneVGPR;
- RegSpillTracker() : CurrentLane(0), SpilledRegisters(), LaneVGPR(0) { }
- /// \p NumRegs The number of consecutive registers what need to be spilled.
- /// This function will ensure that all registers are stored in
- /// the same VGPR.
- /// \returns The lane to be used for storing the first register.
- unsigned reserveLanes(MachineRegisterInfo &MRI, MachineFunction *MF,
- unsigned NumRegs = 1);
- void addSpilledReg(unsigned FrameIndex, unsigned Reg, int Lane = -1);
- const SpilledReg& getSpilledReg(unsigned FrameIndex);
- bool programSpillsRegisters() { return !SpilledRegisters.empty(); }
- };
-
// SIMachineFunctionInfo definition
SIMachineFunctionInfo(const MachineFunction &MF);
SpilledReg getSpilledReg(MachineFunction *MF, unsigned FrameIndex,
unsigned SubIdx);
unsigned PSInputAddr;
- struct RegSpillTracker SpillTracker;
unsigned NumUserSGPRs;
std::map<unsigned, unsigned> LaneVGPRs;
};