| //===-- SystemZRegisterInfo.cpp - SystemZ register information ------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "SystemZRegisterInfo.h" |
| #include "SystemZInstrInfo.h" |
| #include "SystemZSubtarget.h" |
| #include "llvm/CodeGen/LiveIntervals.h" |
| #include "llvm/ADT/SmallSet.h" |
| #include "llvm/CodeGen/MachineInstrBuilder.h" |
| #include "llvm/CodeGen/MachineRegisterInfo.h" |
| #include "llvm/CodeGen/TargetFrameLowering.h" |
| #include "llvm/CodeGen/VirtRegMap.h" |
| |
| using namespace llvm; |
| |
| #define GET_REGINFO_TARGET_DESC |
| #include "SystemZGenRegisterInfo.inc" |
| |
| SystemZRegisterInfo::SystemZRegisterInfo() |
| : SystemZGenRegisterInfo(SystemZ::R14D) {} |
| |
| // Given that MO is a GRX32 operand, return either GR32 or GRH32 if MO |
| // somehow belongs in it. Otherwise, return GRX32. |
| static const TargetRegisterClass *getRC32(MachineOperand &MO, |
| const VirtRegMap *VRM, |
| const MachineRegisterInfo *MRI) { |
| const TargetRegisterClass *RC = MRI->getRegClass(MO.getReg()); |
| |
| if (SystemZ::GR32BitRegClass.hasSubClassEq(RC) || |
| MO.getSubReg() == SystemZ::subreg_l32 || |
| MO.getSubReg() == SystemZ::subreg_hl32) |
| return &SystemZ::GR32BitRegClass; |
| if (SystemZ::GRH32BitRegClass.hasSubClassEq(RC) || |
| MO.getSubReg() == SystemZ::subreg_h32 || |
| MO.getSubReg() == SystemZ::subreg_hh32) |
| return &SystemZ::GRH32BitRegClass; |
| |
| if (VRM && VRM->hasPhys(MO.getReg())) { |
| Register PhysReg = VRM->getPhys(MO.getReg()); |
| if (SystemZ::GR32BitRegClass.contains(PhysReg)) |
| return &SystemZ::GR32BitRegClass; |
| assert (SystemZ::GRH32BitRegClass.contains(PhysReg) && |
| "Phys reg not in GR32 or GRH32?"); |
| return &SystemZ::GRH32BitRegClass; |
| } |
| |
| assert (RC == &SystemZ::GRX32BitRegClass); |
| return RC; |
| } |
| |
| // Pass the registers of RC as hints while making sure that if any of these |
| // registers are copy hints (and therefore already in Hints), hint them |
| // first. |
| static void addHints(ArrayRef<MCPhysReg> Order, |
| SmallVectorImpl<MCPhysReg> &Hints, |
| const TargetRegisterClass *RC, |
| const MachineRegisterInfo *MRI) { |
| SmallSet<unsigned, 4> CopyHints; |
| CopyHints.insert(Hints.begin(), Hints.end()); |
| Hints.clear(); |
| for (MCPhysReg Reg : Order) |
| if (CopyHints.count(Reg) && |
| RC->contains(Reg) && !MRI->isReserved(Reg)) |
| Hints.push_back(Reg); |
| for (MCPhysReg Reg : Order) |
| if (!CopyHints.count(Reg) && |
| RC->contains(Reg) && !MRI->isReserved(Reg)) |
| Hints.push_back(Reg); |
| } |
| |
| bool |
| SystemZRegisterInfo::getRegAllocationHints(unsigned VirtReg, |
| ArrayRef<MCPhysReg> Order, |
| SmallVectorImpl<MCPhysReg> &Hints, |
| const MachineFunction &MF, |
| const VirtRegMap *VRM, |
| const LiveRegMatrix *Matrix) const { |
| const MachineRegisterInfo *MRI = &MF.getRegInfo(); |
| const SystemZSubtarget &Subtarget = MF.getSubtarget<SystemZSubtarget>(); |
| const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo(); |
| |
| bool BaseImplRetVal = TargetRegisterInfo::getRegAllocationHints( |
| VirtReg, Order, Hints, MF, VRM, Matrix); |
| |
| if (VRM != nullptr) { |
| // Add any two address hints after any copy hints. |
| SmallSet<unsigned, 4> TwoAddrHints; |
| for (auto &Use : MRI->reg_nodbg_instructions(VirtReg)) |
| if (SystemZ::getTwoOperandOpcode(Use.getOpcode()) != -1) { |
| const MachineOperand *VRRegMO = nullptr; |
| const MachineOperand *OtherMO = nullptr; |
| const MachineOperand *CommuMO = nullptr; |
| if (VirtReg == Use.getOperand(0).getReg()) { |
| VRRegMO = &Use.getOperand(0); |
| OtherMO = &Use.getOperand(1); |
| if (Use.isCommutable()) |
| CommuMO = &Use.getOperand(2); |
| } else if (VirtReg == Use.getOperand(1).getReg()) { |
| VRRegMO = &Use.getOperand(1); |
| OtherMO = &Use.getOperand(0); |
| } else if (VirtReg == Use.getOperand(2).getReg() && |
| Use.isCommutable()) { |
| VRRegMO = &Use.getOperand(2); |
| OtherMO = &Use.getOperand(0); |
| } else |
| continue; |
| |
| auto tryAddHint = [&](const MachineOperand *MO) -> void { |
| Register Reg = MO->getReg(); |
| Register PhysReg = |
| Register::isPhysicalRegister(Reg) ? Reg : VRM->getPhys(Reg); |
| if (PhysReg) { |
| if (MO->getSubReg()) |
| PhysReg = getSubReg(PhysReg, MO->getSubReg()); |
| if (VRRegMO->getSubReg()) |
| PhysReg = getMatchingSuperReg(PhysReg, VRRegMO->getSubReg(), |
| MRI->getRegClass(VirtReg)); |
| if (!MRI->isReserved(PhysReg) && !is_contained(Hints, PhysReg)) |
| TwoAddrHints.insert(PhysReg); |
| } |
| }; |
| tryAddHint(OtherMO); |
| if (CommuMO) |
| tryAddHint(CommuMO); |
| } |
| for (MCPhysReg OrderReg : Order) |
| if (TwoAddrHints.count(OrderReg)) |
| Hints.push_back(OrderReg); |
| } |
| |
| if (MRI->getRegClass(VirtReg) == &SystemZ::GRX32BitRegClass) { |
| SmallVector<unsigned, 8> Worklist; |
| SmallSet<unsigned, 4> DoneRegs; |
| Worklist.push_back(VirtReg); |
| while (Worklist.size()) { |
| unsigned Reg = Worklist.pop_back_val(); |
| if (!DoneRegs.insert(Reg).second) |
| continue; |
| |
| for (auto &Use : MRI->reg_instructions(Reg)) { |
| // For LOCRMux, see if the other operand is already a high or low |
| // register, and in that case give the corresponding hints for |
| // VirtReg. LOCR instructions need both operands in either high or |
| // low parts. Same handling for SELRMux. |
| if (Use.getOpcode() == SystemZ::LOCRMux || |
| Use.getOpcode() == SystemZ::SELRMux) { |
| MachineOperand &TrueMO = Use.getOperand(1); |
| MachineOperand &FalseMO = Use.getOperand(2); |
| const TargetRegisterClass *RC = |
| TRI->getCommonSubClass(getRC32(FalseMO, VRM, MRI), |
| getRC32(TrueMO, VRM, MRI)); |
| if (Use.getOpcode() == SystemZ::SELRMux) |
| RC = TRI->getCommonSubClass(RC, |
| getRC32(Use.getOperand(0), VRM, MRI)); |
| if (RC && RC != &SystemZ::GRX32BitRegClass) { |
| addHints(Order, Hints, RC, MRI); |
| // Return true to make these hints the only regs available to |
| // RA. This may mean extra spilling but since the alternative is |
| // a jump sequence expansion of the LOCRMux, it is preferred. |
| return true; |
| } |
| |
| // Add the other operand of the LOCRMux to the worklist. |
| Register OtherReg = |
| (TrueMO.getReg() == Reg ? FalseMO.getReg() : TrueMO.getReg()); |
| if (MRI->getRegClass(OtherReg) == &SystemZ::GRX32BitRegClass) |
| Worklist.push_back(OtherReg); |
| } // end LOCRMux |
| else if (Use.getOpcode() == SystemZ::CHIMux || |
| Use.getOpcode() == SystemZ::CFIMux) { |
| if (Use.getOperand(1).getImm() == 0) { |
| bool OnlyLMuxes = true; |
| for (MachineInstr &DefMI : MRI->def_instructions(VirtReg)) |
| if (DefMI.getOpcode() != SystemZ::LMux) |
| OnlyLMuxes = false; |
| if (OnlyLMuxes) { |
| addHints(Order, Hints, &SystemZ::GR32BitRegClass, MRI); |
| // Return false to make these hints preferred but not obligatory. |
| return false; |
| } |
| } |
| } // end CHIMux / CFIMux |
| } |
| } |
| } |
| |
| return BaseImplRetVal; |
| } |
| |
| const MCPhysReg * |
| SystemZRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const { |
| const SystemZSubtarget &Subtarget = MF->getSubtarget<SystemZSubtarget>(); |
| if (MF->getFunction().getCallingConv() == CallingConv::GHC) |
| return CSR_SystemZ_NoRegs_SaveList; |
| if (MF->getFunction().getCallingConv() == CallingConv::AnyReg) |
| return Subtarget.hasVector()? CSR_SystemZ_AllRegs_Vector_SaveList |
| : CSR_SystemZ_AllRegs_SaveList; |
| if (MF->getSubtarget().getTargetLowering()->supportSwiftError() && |
| MF->getFunction().getAttributes().hasAttrSomewhere( |
| Attribute::SwiftError)) |
| return CSR_SystemZ_SwiftError_SaveList; |
| return CSR_SystemZ_SaveList; |
| } |
| |
| const uint32_t * |
| SystemZRegisterInfo::getCallPreservedMask(const MachineFunction &MF, |
| CallingConv::ID CC) const { |
| const SystemZSubtarget &Subtarget = MF.getSubtarget<SystemZSubtarget>(); |
| if (CC == CallingConv::GHC) |
| return CSR_SystemZ_NoRegs_RegMask; |
| if (CC == CallingConv::AnyReg) |
| return Subtarget.hasVector()? CSR_SystemZ_AllRegs_Vector_RegMask |
| : CSR_SystemZ_AllRegs_RegMask; |
| if (MF.getSubtarget().getTargetLowering()->supportSwiftError() && |
| MF.getFunction().getAttributes().hasAttrSomewhere( |
| Attribute::SwiftError)) |
| return CSR_SystemZ_SwiftError_RegMask; |
| return CSR_SystemZ_RegMask; |
| } |
| |
| BitVector |
| SystemZRegisterInfo::getReservedRegs(const MachineFunction &MF) const { |
| BitVector Reserved(getNumRegs()); |
| const SystemZFrameLowering *TFI = getFrameLowering(MF); |
| |
| if (TFI->hasFP(MF)) { |
| // R11D is the frame pointer. Reserve all aliases. |
| Reserved.set(SystemZ::R11D); |
| Reserved.set(SystemZ::R11L); |
| Reserved.set(SystemZ::R11H); |
| Reserved.set(SystemZ::R10Q); |
| } |
| |
| // R15D is the stack pointer. Reserve all aliases. |
| Reserved.set(SystemZ::R15D); |
| Reserved.set(SystemZ::R15L); |
| Reserved.set(SystemZ::R15H); |
| Reserved.set(SystemZ::R14Q); |
| |
| // A0 and A1 hold the thread pointer. |
| Reserved.set(SystemZ::A0); |
| Reserved.set(SystemZ::A1); |
| |
| // FPC is the floating-point control register. |
| Reserved.set(SystemZ::FPC); |
| |
| return Reserved; |
| } |
| |
| void |
| SystemZRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator MI, |
| int SPAdj, unsigned FIOperandNum, |
| RegScavenger *RS) const { |
| assert(SPAdj == 0 && "Outgoing arguments should be part of the frame"); |
| |
| MachineBasicBlock &MBB = *MI->getParent(); |
| MachineFunction &MF = *MBB.getParent(); |
| auto *TII = |
| static_cast<const SystemZInstrInfo *>(MF.getSubtarget().getInstrInfo()); |
| const SystemZFrameLowering *TFI = getFrameLowering(MF); |
| DebugLoc DL = MI->getDebugLoc(); |
| |
| // Decompose the frame index into a base and offset. |
| int FrameIndex = MI->getOperand(FIOperandNum).getIndex(); |
| unsigned BasePtr; |
| int64_t Offset = (TFI->getFrameIndexReference(MF, FrameIndex, BasePtr) + |
| MI->getOperand(FIOperandNum + 1).getImm()); |
| |
| // Special handling of dbg_value instructions. |
| if (MI->isDebugValue()) { |
| MI->getOperand(FIOperandNum).ChangeToRegister(BasePtr, /*isDef*/ false); |
| MI->getOperand(FIOperandNum + 1).ChangeToImmediate(Offset); |
| return; |
| } |
| |
| // See if the offset is in range, or if an equivalent instruction that |
| // accepts the offset exists. |
| unsigned Opcode = MI->getOpcode(); |
| unsigned OpcodeForOffset = TII->getOpcodeForOffset(Opcode, Offset); |
| if (OpcodeForOffset) { |
| if (OpcodeForOffset == SystemZ::LE && |
| MF.getSubtarget<SystemZSubtarget>().hasVector()) { |
| // If LE is ok for offset, use LDE instead on z13. |
| OpcodeForOffset = SystemZ::LDE32; |
| } |
| MI->getOperand(FIOperandNum).ChangeToRegister(BasePtr, false); |
| } |
| else { |
| // Create an anchor point that is in range. Start at 0xffff so that |
| // can use LLILH to load the immediate. |
| int64_t OldOffset = Offset; |
| int64_t Mask = 0xffff; |
| do { |
| Offset = OldOffset & Mask; |
| OpcodeForOffset = TII->getOpcodeForOffset(Opcode, Offset); |
| Mask >>= 1; |
| assert(Mask && "One offset must be OK"); |
| } while (!OpcodeForOffset); |
| |
| Register ScratchReg = |
| MF.getRegInfo().createVirtualRegister(&SystemZ::ADDR64BitRegClass); |
| int64_t HighOffset = OldOffset - Offset; |
| |
| if (MI->getDesc().TSFlags & SystemZII::HasIndex |
| && MI->getOperand(FIOperandNum + 2).getReg() == 0) { |
| // Load the offset into the scratch register and use it as an index. |
| // The scratch register then dies here. |
| TII->loadImmediate(MBB, MI, ScratchReg, HighOffset); |
| MI->getOperand(FIOperandNum).ChangeToRegister(BasePtr, false); |
| MI->getOperand(FIOperandNum + 2).ChangeToRegister(ScratchReg, |
| false, false, true); |
| } else { |
| // Load the anchor address into a scratch register. |
| unsigned LAOpcode = TII->getOpcodeForOffset(SystemZ::LA, HighOffset); |
| if (LAOpcode) |
| BuildMI(MBB, MI, DL, TII->get(LAOpcode),ScratchReg) |
| .addReg(BasePtr).addImm(HighOffset).addReg(0); |
| else { |
| // Load the high offset into the scratch register and use it as |
| // an index. |
| TII->loadImmediate(MBB, MI, ScratchReg, HighOffset); |
| BuildMI(MBB, MI, DL, TII->get(SystemZ::AGR),ScratchReg) |
| .addReg(ScratchReg, RegState::Kill).addReg(BasePtr); |
| } |
| |
| // Use the scratch register as the base. It then dies here. |
| MI->getOperand(FIOperandNum).ChangeToRegister(ScratchReg, |
| false, false, true); |
| } |
| } |
| MI->setDesc(TII->get(OpcodeForOffset)); |
| MI->getOperand(FIOperandNum + 1).ChangeToImmediate(Offset); |
| } |
| |
| bool SystemZRegisterInfo::shouldCoalesce(MachineInstr *MI, |
| const TargetRegisterClass *SrcRC, |
| unsigned SubReg, |
| const TargetRegisterClass *DstRC, |
| unsigned DstSubReg, |
| const TargetRegisterClass *NewRC, |
| LiveIntervals &LIS) const { |
| assert (MI->isCopy() && "Only expecting COPY instructions"); |
| |
| // Coalesce anything which is not a COPY involving a subreg to/from GR128. |
| if (!(NewRC->hasSuperClassEq(&SystemZ::GR128BitRegClass) && |
| (getRegSizeInBits(*SrcRC) <= 64 || getRegSizeInBits(*DstRC) <= 64))) |
| return true; |
| |
| // Allow coalescing of a GR128 subreg COPY only if the live ranges are small |
| // and local to one MBB with not too much interferring registers. Otherwise |
| // regalloc may run out of registers. |
| |
| unsigned WideOpNo = (getRegSizeInBits(*SrcRC) == 128 ? 1 : 0); |
| Register GR128Reg = MI->getOperand(WideOpNo).getReg(); |
| Register GRNarReg = MI->getOperand((WideOpNo == 1) ? 0 : 1).getReg(); |
| LiveInterval &IntGR128 = LIS.getInterval(GR128Reg); |
| LiveInterval &IntGRNar = LIS.getInterval(GRNarReg); |
| |
| // Check that the two virtual registers are local to MBB. |
| MachineBasicBlock *MBB = MI->getParent(); |
| MachineInstr *FirstMI_GR128 = |
| LIS.getInstructionFromIndex(IntGR128.beginIndex()); |
| MachineInstr *FirstMI_GRNar = |
| LIS.getInstructionFromIndex(IntGRNar.beginIndex()); |
| MachineInstr *LastMI_GR128 = LIS.getInstructionFromIndex(IntGR128.endIndex()); |
| MachineInstr *LastMI_GRNar = LIS.getInstructionFromIndex(IntGRNar.endIndex()); |
| if ((!FirstMI_GR128 || FirstMI_GR128->getParent() != MBB) || |
| (!FirstMI_GRNar || FirstMI_GRNar->getParent() != MBB) || |
| (!LastMI_GR128 || LastMI_GR128->getParent() != MBB) || |
| (!LastMI_GRNar || LastMI_GRNar->getParent() != MBB)) |
| return false; |
| |
| MachineBasicBlock::iterator MII = nullptr, MEE = nullptr; |
| if (WideOpNo == 1) { |
| MII = FirstMI_GR128; |
| MEE = LastMI_GRNar; |
| } else { |
| MII = FirstMI_GRNar; |
| MEE = LastMI_GR128; |
| } |
| |
| // Check if coalescing seems safe by finding the set of clobbered physreg |
| // pairs in the region. |
| BitVector PhysClobbered(getNumRegs()); |
| MEE++; |
| for (; MII != MEE; ++MII) { |
| for (const MachineOperand &MO : MII->operands()) |
| if (MO.isReg() && Register::isPhysicalRegister(MO.getReg())) { |
| for (MCSuperRegIterator SI(MO.getReg(), this, true/*IncludeSelf*/); |
| SI.isValid(); ++SI) |
| if (NewRC->contains(*SI)) { |
| PhysClobbered.set(*SI); |
| break; |
| } |
| } |
| } |
| |
| // Demand an arbitrary margin of free regs. |
| unsigned const DemandedFreeGR128 = 3; |
| if (PhysClobbered.count() > (NewRC->getNumRegs() - DemandedFreeGR128)) |
| return false; |
| |
| return true; |
| } |
| |
| Register |
| SystemZRegisterInfo::getFrameRegister(const MachineFunction &MF) const { |
| const SystemZFrameLowering *TFI = getFrameLowering(MF); |
| return TFI->hasFP(MF) ? SystemZ::R11D : SystemZ::R15D; |
| } |
| |
| const TargetRegisterClass * |
| SystemZRegisterInfo::getCrossCopyRegClass(const TargetRegisterClass *RC) const { |
| if (RC == &SystemZ::CCRRegClass) |
| return &SystemZ::GR32BitRegClass; |
| return RC; |
| } |
| |
