| //===-- LanaiInstrInfo.cpp - Lanai Instruction Information ------*- C++ -*-===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains the Lanai implementation of the TargetInstrInfo class. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "LanaiInstrInfo.h" |
| #include "LanaiAluCode.h" |
| #include "LanaiCondCode.h" |
| #include "MCTargetDesc/LanaiBaseInfo.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/CodeGen/MachineFunctionPass.h" |
| #include "llvm/CodeGen/MachineInstrBuilder.h" |
| #include "llvm/CodeGen/MachineRegisterInfo.h" |
| #include "llvm/MC/TargetRegistry.h" |
| #include "llvm/Support/ErrorHandling.h" |
| |
| using namespace llvm; |
| |
| #define GET_INSTRINFO_CTOR_DTOR |
| #include "LanaiGenInstrInfo.inc" |
| |
| LanaiInstrInfo::LanaiInstrInfo() |
| : LanaiGenInstrInfo(Lanai::ADJCALLSTACKDOWN, Lanai::ADJCALLSTACKUP), |
| RegisterInfo() {} |
| |
| void LanaiInstrInfo::copyPhysReg(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator Position, |
| const DebugLoc &DL, |
| MCRegister DestinationRegister, |
| MCRegister SourceRegister, |
| bool KillSource) const { |
| if (!Lanai::GPRRegClass.contains(DestinationRegister, SourceRegister)) { |
| llvm_unreachable("Impossible reg-to-reg copy"); |
| } |
| |
| BuildMI(MBB, Position, DL, get(Lanai::OR_I_LO), DestinationRegister) |
| .addReg(SourceRegister, getKillRegState(KillSource)) |
| .addImm(0); |
| } |
| |
| void LanaiInstrInfo::storeRegToStackSlot( |
| MachineBasicBlock &MBB, MachineBasicBlock::iterator Position, |
| Register SourceRegister, bool IsKill, int FrameIndex, |
| const TargetRegisterClass *RegisterClass, |
| const TargetRegisterInfo * /*RegisterInfo*/) const { |
| DebugLoc DL; |
| if (Position != MBB.end()) { |
| DL = Position->getDebugLoc(); |
| } |
| |
| if (!Lanai::GPRRegClass.hasSubClassEq(RegisterClass)) { |
| llvm_unreachable("Can't store this register to stack slot"); |
| } |
| BuildMI(MBB, Position, DL, get(Lanai::SW_RI)) |
| .addReg(SourceRegister, getKillRegState(IsKill)) |
| .addFrameIndex(FrameIndex) |
| .addImm(0) |
| .addImm(LPAC::ADD); |
| } |
| |
| void LanaiInstrInfo::loadRegFromStackSlot( |
| MachineBasicBlock &MBB, MachineBasicBlock::iterator Position, |
| Register DestinationRegister, int FrameIndex, |
| const TargetRegisterClass *RegisterClass, |
| const TargetRegisterInfo * /*RegisterInfo*/) const { |
| DebugLoc DL; |
| if (Position != MBB.end()) { |
| DL = Position->getDebugLoc(); |
| } |
| |
| if (!Lanai::GPRRegClass.hasSubClassEq(RegisterClass)) { |
| llvm_unreachable("Can't load this register from stack slot"); |
| } |
| BuildMI(MBB, Position, DL, get(Lanai::LDW_RI), DestinationRegister) |
| .addFrameIndex(FrameIndex) |
| .addImm(0) |
| .addImm(LPAC::ADD); |
| } |
| |
| bool LanaiInstrInfo::areMemAccessesTriviallyDisjoint( |
| const MachineInstr &MIa, const MachineInstr &MIb) const { |
| assert(MIa.mayLoadOrStore() && "MIa must be a load or store."); |
| assert(MIb.mayLoadOrStore() && "MIb must be a load or store."); |
| |
| if (MIa.hasUnmodeledSideEffects() || MIb.hasUnmodeledSideEffects() || |
| MIa.hasOrderedMemoryRef() || MIb.hasOrderedMemoryRef()) |
| return false; |
| |
| // Retrieve the base register, offset from the base register and width. Width |
| // is the size of memory that is being loaded/stored (e.g. 1, 2, 4). If |
| // base registers are identical, and the offset of a lower memory access + |
| // the width doesn't overlap the offset of a higher memory access, |
| // then the memory accesses are different. |
| const TargetRegisterInfo *TRI = &getRegisterInfo(); |
| const MachineOperand *BaseOpA = nullptr, *BaseOpB = nullptr; |
| int64_t OffsetA = 0, OffsetB = 0; |
| unsigned int WidthA = 0, WidthB = 0; |
| if (getMemOperandWithOffsetWidth(MIa, BaseOpA, OffsetA, WidthA, TRI) && |
| getMemOperandWithOffsetWidth(MIb, BaseOpB, OffsetB, WidthB, TRI)) { |
| if (BaseOpA->isIdenticalTo(*BaseOpB)) { |
| int LowOffset = std::min(OffsetA, OffsetB); |
| int HighOffset = std::max(OffsetA, OffsetB); |
| int LowWidth = (LowOffset == OffsetA) ? WidthA : WidthB; |
| if (LowOffset + LowWidth <= HighOffset) |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| bool LanaiInstrInfo::expandPostRAPseudo(MachineInstr & /*MI*/) const { |
| return false; |
| } |
| |
| static LPCC::CondCode getOppositeCondition(LPCC::CondCode CC) { |
| switch (CC) { |
| case LPCC::ICC_T: // true |
| return LPCC::ICC_F; |
| case LPCC::ICC_F: // false |
| return LPCC::ICC_T; |
| case LPCC::ICC_HI: // high |
| return LPCC::ICC_LS; |
| case LPCC::ICC_LS: // low or same |
| return LPCC::ICC_HI; |
| case LPCC::ICC_CC: // carry cleared |
| return LPCC::ICC_CS; |
| case LPCC::ICC_CS: // carry set |
| return LPCC::ICC_CC; |
| case LPCC::ICC_NE: // not equal |
| return LPCC::ICC_EQ; |
| case LPCC::ICC_EQ: // equal |
| return LPCC::ICC_NE; |
| case LPCC::ICC_VC: // oVerflow cleared |
| return LPCC::ICC_VS; |
| case LPCC::ICC_VS: // oVerflow set |
| return LPCC::ICC_VC; |
| case LPCC::ICC_PL: // plus (note: 0 is "minus" too here) |
| return LPCC::ICC_MI; |
| case LPCC::ICC_MI: // minus |
| return LPCC::ICC_PL; |
| case LPCC::ICC_GE: // greater than or equal |
| return LPCC::ICC_LT; |
| case LPCC::ICC_LT: // less than |
| return LPCC::ICC_GE; |
| case LPCC::ICC_GT: // greater than |
| return LPCC::ICC_LE; |
| case LPCC::ICC_LE: // less than or equal |
| return LPCC::ICC_GT; |
| default: |
| llvm_unreachable("Invalid condtional code"); |
| } |
| } |
| |
| std::pair<unsigned, unsigned> |
| LanaiInstrInfo::decomposeMachineOperandsTargetFlags(unsigned TF) const { |
| return std::make_pair(TF, 0u); |
| } |
| |
| ArrayRef<std::pair<unsigned, const char *>> |
| LanaiInstrInfo::getSerializableDirectMachineOperandTargetFlags() const { |
| using namespace LanaiII; |
| static const std::pair<unsigned, const char *> TargetFlags[] = { |
| {MO_ABS_HI, "lanai-hi"}, |
| {MO_ABS_LO, "lanai-lo"}, |
| {MO_NO_FLAG, "lanai-nf"}}; |
| return makeArrayRef(TargetFlags); |
| } |
| |
| bool LanaiInstrInfo::analyzeCompare(const MachineInstr &MI, Register &SrcReg, |
| Register &SrcReg2, int64_t &CmpMask, |
| int64_t &CmpValue) const { |
| switch (MI.getOpcode()) { |
| default: |
| break; |
| case Lanai::SFSUB_F_RI_LO: |
| case Lanai::SFSUB_F_RI_HI: |
| SrcReg = MI.getOperand(0).getReg(); |
| SrcReg2 = Register(); |
| CmpMask = ~0; |
| CmpValue = MI.getOperand(1).getImm(); |
| return true; |
| case Lanai::SFSUB_F_RR: |
| SrcReg = MI.getOperand(0).getReg(); |
| SrcReg2 = MI.getOperand(1).getReg(); |
| CmpMask = ~0; |
| CmpValue = 0; |
| return true; |
| } |
| |
| return false; |
| } |
| |
| // isRedundantFlagInstr - check whether the first instruction, whose only |
| // purpose is to update flags, can be made redundant. |
| // * SFSUB_F_RR can be made redundant by SUB_RI if the operands are the same. |
| // * SFSUB_F_RI can be made redundant by SUB_I if the operands are the same. |
| inline static bool isRedundantFlagInstr(MachineInstr *CmpI, unsigned SrcReg, |
| unsigned SrcReg2, int64_t ImmValue, |
| MachineInstr *OI) { |
| if (CmpI->getOpcode() == Lanai::SFSUB_F_RR && |
| OI->getOpcode() == Lanai::SUB_R && |
| ((OI->getOperand(1).getReg() == SrcReg && |
| OI->getOperand(2).getReg() == SrcReg2) || |
| (OI->getOperand(1).getReg() == SrcReg2 && |
| OI->getOperand(2).getReg() == SrcReg))) |
| return true; |
| |
| if (((CmpI->getOpcode() == Lanai::SFSUB_F_RI_LO && |
| OI->getOpcode() == Lanai::SUB_I_LO) || |
| (CmpI->getOpcode() == Lanai::SFSUB_F_RI_HI && |
| OI->getOpcode() == Lanai::SUB_I_HI)) && |
| OI->getOperand(1).getReg() == SrcReg && |
| OI->getOperand(2).getImm() == ImmValue) |
| return true; |
| return false; |
| } |
| |
| inline static unsigned flagSettingOpcodeVariant(unsigned OldOpcode) { |
| switch (OldOpcode) { |
| case Lanai::ADD_I_HI: |
| return Lanai::ADD_F_I_HI; |
| case Lanai::ADD_I_LO: |
| return Lanai::ADD_F_I_LO; |
| case Lanai::ADD_R: |
| return Lanai::ADD_F_R; |
| case Lanai::ADDC_I_HI: |
| return Lanai::ADDC_F_I_HI; |
| case Lanai::ADDC_I_LO: |
| return Lanai::ADDC_F_I_LO; |
| case Lanai::ADDC_R: |
| return Lanai::ADDC_F_R; |
| case Lanai::AND_I_HI: |
| return Lanai::AND_F_I_HI; |
| case Lanai::AND_I_LO: |
| return Lanai::AND_F_I_LO; |
| case Lanai::AND_R: |
| return Lanai::AND_F_R; |
| case Lanai::OR_I_HI: |
| return Lanai::OR_F_I_HI; |
| case Lanai::OR_I_LO: |
| return Lanai::OR_F_I_LO; |
| case Lanai::OR_R: |
| return Lanai::OR_F_R; |
| case Lanai::SL_I: |
| return Lanai::SL_F_I; |
| case Lanai::SRL_R: |
| return Lanai::SRL_F_R; |
| case Lanai::SA_I: |
| return Lanai::SA_F_I; |
| case Lanai::SRA_R: |
| return Lanai::SRA_F_R; |
| case Lanai::SUB_I_HI: |
| return Lanai::SUB_F_I_HI; |
| case Lanai::SUB_I_LO: |
| return Lanai::SUB_F_I_LO; |
| case Lanai::SUB_R: |
| return Lanai::SUB_F_R; |
| case Lanai::SUBB_I_HI: |
| return Lanai::SUBB_F_I_HI; |
| case Lanai::SUBB_I_LO: |
| return Lanai::SUBB_F_I_LO; |
| case Lanai::SUBB_R: |
| return Lanai::SUBB_F_R; |
| case Lanai::XOR_I_HI: |
| return Lanai::XOR_F_I_HI; |
| case Lanai::XOR_I_LO: |
| return Lanai::XOR_F_I_LO; |
| case Lanai::XOR_R: |
| return Lanai::XOR_F_R; |
| default: |
| return Lanai::NOP; |
| } |
| } |
| |
| bool LanaiInstrInfo::optimizeCompareInstr( |
| MachineInstr &CmpInstr, Register SrcReg, Register SrcReg2, |
| int64_t /*CmpMask*/, int64_t CmpValue, |
| const MachineRegisterInfo *MRI) const { |
| // Get the unique definition of SrcReg. |
| MachineInstr *MI = MRI->getUniqueVRegDef(SrcReg); |
| if (!MI) |
| return false; |
| |
| // Get ready to iterate backward from CmpInstr. |
| MachineBasicBlock::iterator I = CmpInstr, E = MI, |
| B = CmpInstr.getParent()->begin(); |
| |
| // Early exit if CmpInstr is at the beginning of the BB. |
| if (I == B) |
| return false; |
| |
| // There are two possible candidates which can be changed to set SR: |
| // One is MI, the other is a SUB instruction. |
| // * For SFSUB_F_RR(r1,r2), we are looking for SUB(r1,r2) or SUB(r2,r1). |
| // * For SFSUB_F_RI(r1, CmpValue), we are looking for SUB(r1, CmpValue). |
| MachineInstr *Sub = nullptr; |
| if (SrcReg2 != 0) |
| // MI is not a candidate to transform into a flag setting instruction. |
| MI = nullptr; |
| else if (MI->getParent() != CmpInstr.getParent() || CmpValue != 0) { |
| // Conservatively refuse to convert an instruction which isn't in the same |
| // BB as the comparison. Don't return if SFSUB_F_RI and CmpValue != 0 as Sub |
| // may still be a candidate. |
| if (CmpInstr.getOpcode() == Lanai::SFSUB_F_RI_LO) |
| MI = nullptr; |
| else |
| return false; |
| } |
| |
| // Check that SR isn't set between the comparison instruction and the |
| // instruction we want to change while searching for Sub. |
| const TargetRegisterInfo *TRI = &getRegisterInfo(); |
| for (--I; I != E; --I) { |
| const MachineInstr &Instr = *I; |
| |
| if (Instr.modifiesRegister(Lanai::SR, TRI) || |
| Instr.readsRegister(Lanai::SR, TRI)) |
| // This instruction modifies or uses SR after the one we want to change. |
| // We can't do this transformation. |
| return false; |
| |
| // Check whether CmpInstr can be made redundant by the current instruction. |
| if (isRedundantFlagInstr(&CmpInstr, SrcReg, SrcReg2, CmpValue, &*I)) { |
| Sub = &*I; |
| break; |
| } |
| |
| // Don't search outside the containing basic block. |
| if (I == B) |
| return false; |
| } |
| |
| // Return false if no candidates exist. |
| if (!MI && !Sub) |
| return false; |
| |
| // The single candidate is called MI. |
| if (!MI) |
| MI = Sub; |
| |
| if (flagSettingOpcodeVariant(MI->getOpcode()) != Lanai::NOP) { |
| bool isSafe = false; |
| |
| SmallVector<std::pair<MachineOperand *, LPCC::CondCode>, 4> |
| OperandsToUpdate; |
| I = CmpInstr; |
| E = CmpInstr.getParent()->end(); |
| while (!isSafe && ++I != E) { |
| const MachineInstr &Instr = *I; |
| for (unsigned IO = 0, EO = Instr.getNumOperands(); !isSafe && IO != EO; |
| ++IO) { |
| const MachineOperand &MO = Instr.getOperand(IO); |
| if (MO.isRegMask() && MO.clobbersPhysReg(Lanai::SR)) { |
| isSafe = true; |
| break; |
| } |
| if (!MO.isReg() || MO.getReg() != Lanai::SR) |
| continue; |
| if (MO.isDef()) { |
| isSafe = true; |
| break; |
| } |
| // Condition code is after the operand before SR. |
| LPCC::CondCode CC; |
| CC = (LPCC::CondCode)Instr.getOperand(IO - 1).getImm(); |
| |
| if (Sub) { |
| LPCC::CondCode NewCC = getOppositeCondition(CC); |
| if (NewCC == LPCC::ICC_T) |
| return false; |
| // If we have SUB(r1, r2) and CMP(r2, r1), the condition code based on |
| // CMP needs to be updated to be based on SUB. Push the condition |
| // code operands to OperandsToUpdate. If it is safe to remove |
| // CmpInstr, the condition code of these operands will be modified. |
| if (SrcReg2 != 0 && Sub->getOperand(1).getReg() == SrcReg2 && |
| Sub->getOperand(2).getReg() == SrcReg) { |
| OperandsToUpdate.push_back( |
| std::make_pair(&((*I).getOperand(IO - 1)), NewCC)); |
| } |
| } else { |
| // No Sub, so this is x = <op> y, z; cmp x, 0. |
| switch (CC) { |
| case LPCC::ICC_EQ: // Z |
| case LPCC::ICC_NE: // Z |
| case LPCC::ICC_MI: // N |
| case LPCC::ICC_PL: // N |
| case LPCC::ICC_F: // none |
| case LPCC::ICC_T: // none |
| // SR can be used multiple times, we should continue. |
| break; |
| case LPCC::ICC_CS: // C |
| case LPCC::ICC_CC: // C |
| case LPCC::ICC_VS: // V |
| case LPCC::ICC_VC: // V |
| case LPCC::ICC_HI: // C Z |
| case LPCC::ICC_LS: // C Z |
| case LPCC::ICC_GE: // N V |
| case LPCC::ICC_LT: // N V |
| case LPCC::ICC_GT: // Z N V |
| case LPCC::ICC_LE: // Z N V |
| // The instruction uses the V bit or C bit which is not safe. |
| return false; |
| case LPCC::UNKNOWN: |
| return false; |
| } |
| } |
| } |
| } |
| |
| // If SR is not killed nor re-defined, we should check whether it is |
| // live-out. If it is live-out, do not optimize. |
| if (!isSafe) { |
| MachineBasicBlock *MBB = CmpInstr.getParent(); |
| for (const MachineBasicBlock *Succ : MBB->successors()) |
| if (Succ->isLiveIn(Lanai::SR)) |
| return false; |
| } |
| |
| // Toggle the optional operand to SR. |
| MI->setDesc(get(flagSettingOpcodeVariant(MI->getOpcode()))); |
| MI->addRegisterDefined(Lanai::SR); |
| CmpInstr.eraseFromParent(); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| bool LanaiInstrInfo::analyzeSelect(const MachineInstr &MI, |
| SmallVectorImpl<MachineOperand> &Cond, |
| unsigned &TrueOp, unsigned &FalseOp, |
| bool &Optimizable) const { |
| assert(MI.getOpcode() == Lanai::SELECT && "unknown select instruction"); |
| // Select operands: |
| // 0: Def. |
| // 1: True use. |
| // 2: False use. |
| // 3: Condition code. |
| TrueOp = 1; |
| FalseOp = 2; |
| Cond.push_back(MI.getOperand(3)); |
| Optimizable = true; |
| return false; |
| } |
| |
| // Identify instructions that can be folded into a SELECT instruction, and |
| // return the defining instruction. |
| static MachineInstr *canFoldIntoSelect(Register Reg, |
| const MachineRegisterInfo &MRI) { |
| if (!Reg.isVirtual()) |
| return nullptr; |
| if (!MRI.hasOneNonDBGUse(Reg)) |
| return nullptr; |
| MachineInstr *MI = MRI.getVRegDef(Reg); |
| if (!MI) |
| return nullptr; |
| // MI is folded into the SELECT by predicating it. |
| if (!MI->isPredicable()) |
| return nullptr; |
| // Check if MI has any non-dead defs or physreg uses. This also detects |
| // predicated instructions which will be reading SR. |
| for (const MachineOperand &MO : llvm::drop_begin(MI->operands(), 1)) { |
| // Reject frame index operands. |
| if (MO.isFI() || MO.isCPI() || MO.isJTI()) |
| return nullptr; |
| if (!MO.isReg()) |
| continue; |
| // MI can't have any tied operands, that would conflict with predication. |
| if (MO.isTied()) |
| return nullptr; |
| if (Register::isPhysicalRegister(MO.getReg())) |
| return nullptr; |
| if (MO.isDef() && !MO.isDead()) |
| return nullptr; |
| } |
| bool DontMoveAcrossStores = true; |
| if (!MI->isSafeToMove(/*AliasAnalysis=*/nullptr, DontMoveAcrossStores)) |
| return nullptr; |
| return MI; |
| } |
| |
| MachineInstr * |
| LanaiInstrInfo::optimizeSelect(MachineInstr &MI, |
| SmallPtrSetImpl<MachineInstr *> &SeenMIs, |
| bool /*PreferFalse*/) const { |
| assert(MI.getOpcode() == Lanai::SELECT && "unknown select instruction"); |
| MachineRegisterInfo &MRI = MI.getParent()->getParent()->getRegInfo(); |
| MachineInstr *DefMI = canFoldIntoSelect(MI.getOperand(1).getReg(), MRI); |
| bool Invert = !DefMI; |
| if (!DefMI) |
| DefMI = canFoldIntoSelect(MI.getOperand(2).getReg(), MRI); |
| if (!DefMI) |
| return nullptr; |
| |
| // Find new register class to use. |
| MachineOperand FalseReg = MI.getOperand(Invert ? 1 : 2); |
| Register DestReg = MI.getOperand(0).getReg(); |
| const TargetRegisterClass *PreviousClass = MRI.getRegClass(FalseReg.getReg()); |
| if (!MRI.constrainRegClass(DestReg, PreviousClass)) |
| return nullptr; |
| |
| // Create a new predicated version of DefMI. |
| MachineInstrBuilder NewMI = |
| BuildMI(*MI.getParent(), MI, MI.getDebugLoc(), DefMI->getDesc(), DestReg); |
| |
| // Copy all the DefMI operands, excluding its (null) predicate. |
| const MCInstrDesc &DefDesc = DefMI->getDesc(); |
| for (unsigned i = 1, e = DefDesc.getNumOperands(); |
| i != e && !DefDesc.OpInfo[i].isPredicate(); ++i) |
| NewMI.add(DefMI->getOperand(i)); |
| |
| unsigned CondCode = MI.getOperand(3).getImm(); |
| if (Invert) |
| NewMI.addImm(getOppositeCondition(LPCC::CondCode(CondCode))); |
| else |
| NewMI.addImm(CondCode); |
| NewMI.copyImplicitOps(MI); |
| |
| // The output register value when the predicate is false is an implicit |
| // register operand tied to the first def. The tie makes the register |
| // allocator ensure the FalseReg is allocated the same register as operand 0. |
| FalseReg.setImplicit(); |
| NewMI.add(FalseReg); |
| NewMI->tieOperands(0, NewMI->getNumOperands() - 1); |
| |
| // Update SeenMIs set: register newly created MI and erase removed DefMI. |
| SeenMIs.insert(NewMI); |
| SeenMIs.erase(DefMI); |
| |
| // If MI is inside a loop, and DefMI is outside the loop, then kill flags on |
| // DefMI would be invalid when transferred inside the loop. Checking for a |
| // loop is expensive, but at least remove kill flags if they are in different |
| // BBs. |
| if (DefMI->getParent() != MI.getParent()) |
| NewMI->clearKillInfo(); |
| |
| // The caller will erase MI, but not DefMI. |
| DefMI->eraseFromParent(); |
| return NewMI; |
| } |
| |
| // The analyzeBranch function is used to examine conditional instructions and |
| // remove unnecessary instructions. This method is used by BranchFolder and |
| // IfConverter machine function passes to improve the CFG. |
| // - TrueBlock is set to the destination if condition evaluates true (it is the |
| // nullptr if the destination is the fall-through branch); |
| // - FalseBlock is set to the destination if condition evaluates to false (it |
| // is the nullptr if the branch is unconditional); |
| // - condition is populated with machine operands needed to generate the branch |
| // to insert in insertBranch; |
| // Returns: false if branch could successfully be analyzed. |
| bool LanaiInstrInfo::analyzeBranch(MachineBasicBlock &MBB, |
| MachineBasicBlock *&TrueBlock, |
| MachineBasicBlock *&FalseBlock, |
| SmallVectorImpl<MachineOperand> &Condition, |
| bool AllowModify) const { |
| // Iterator to current instruction being considered. |
| MachineBasicBlock::iterator Instruction = MBB.end(); |
| |
| // Start from the bottom of the block and work up, examining the |
| // terminator instructions. |
| while (Instruction != MBB.begin()) { |
| --Instruction; |
| |
| // Skip over debug instructions. |
| if (Instruction->isDebugInstr()) |
| continue; |
| |
| // Working from the bottom, when we see a non-terminator |
| // instruction, we're done. |
| if (!isUnpredicatedTerminator(*Instruction)) |
| break; |
| |
| // A terminator that isn't a branch can't easily be handled |
| // by this analysis. |
| if (!Instruction->isBranch()) |
| return true; |
| |
| // Handle unconditional branches. |
| if (Instruction->getOpcode() == Lanai::BT) { |
| if (!AllowModify) { |
| TrueBlock = Instruction->getOperand(0).getMBB(); |
| continue; |
| } |
| |
| // If the block has any instructions after a branch, delete them. |
| while (std::next(Instruction) != MBB.end()) { |
| std::next(Instruction)->eraseFromParent(); |
| } |
| |
| Condition.clear(); |
| FalseBlock = nullptr; |
| |
| // Delete the jump if it's equivalent to a fall-through. |
| if (MBB.isLayoutSuccessor(Instruction->getOperand(0).getMBB())) { |
| TrueBlock = nullptr; |
| Instruction->eraseFromParent(); |
| Instruction = MBB.end(); |
| continue; |
| } |
| |
| // TrueBlock is used to indicate the unconditional destination. |
| TrueBlock = Instruction->getOperand(0).getMBB(); |
| continue; |
| } |
| |
| // Handle conditional branches |
| unsigned Opcode = Instruction->getOpcode(); |
| if (Opcode != Lanai::BRCC) |
| return true; // Unknown opcode. |
| |
| // Multiple conditional branches are not handled here so only proceed if |
| // there are no conditions enqueued. |
| if (Condition.empty()) { |
| LPCC::CondCode BranchCond = |
| static_cast<LPCC::CondCode>(Instruction->getOperand(1).getImm()); |
| |
| // TrueBlock is the target of the previously seen unconditional branch. |
| FalseBlock = TrueBlock; |
| TrueBlock = Instruction->getOperand(0).getMBB(); |
| Condition.push_back(MachineOperand::CreateImm(BranchCond)); |
| continue; |
| } |
| |
| // Multiple conditional branches are not handled. |
| return true; |
| } |
| |
| // Return false indicating branch successfully analyzed. |
| return false; |
| } |
| |
| // reverseBranchCondition - Reverses the branch condition of the specified |
| // condition list, returning false on success and true if it cannot be |
| // reversed. |
| bool LanaiInstrInfo::reverseBranchCondition( |
| SmallVectorImpl<llvm::MachineOperand> &Condition) const { |
| assert((Condition.size() == 1) && |
| "Lanai branch conditions should have one component."); |
| |
| LPCC::CondCode BranchCond = |
| static_cast<LPCC::CondCode>(Condition[0].getImm()); |
| Condition[0].setImm(getOppositeCondition(BranchCond)); |
| return false; |
| } |
| |
| // Insert the branch with condition specified in condition and given targets |
| // (TrueBlock and FalseBlock). This function returns the number of machine |
| // instructions inserted. |
| unsigned LanaiInstrInfo::insertBranch(MachineBasicBlock &MBB, |
| MachineBasicBlock *TrueBlock, |
| MachineBasicBlock *FalseBlock, |
| ArrayRef<MachineOperand> Condition, |
| const DebugLoc &DL, |
| int *BytesAdded) const { |
| // Shouldn't be a fall through. |
| assert(TrueBlock && "insertBranch must not be told to insert a fallthrough"); |
| assert(!BytesAdded && "code size not handled"); |
| |
| // If condition is empty then an unconditional branch is being inserted. |
| if (Condition.empty()) { |
| assert(!FalseBlock && "Unconditional branch with multiple successors!"); |
| BuildMI(&MBB, DL, get(Lanai::BT)).addMBB(TrueBlock); |
| return 1; |
| } |
| |
| // Else a conditional branch is inserted. |
| assert((Condition.size() == 1) && |
| "Lanai branch conditions should have one component."); |
| unsigned ConditionalCode = Condition[0].getImm(); |
| BuildMI(&MBB, DL, get(Lanai::BRCC)).addMBB(TrueBlock).addImm(ConditionalCode); |
| |
| // If no false block, then false behavior is fall through and no branch needs |
| // to be inserted. |
| if (!FalseBlock) |
| return 1; |
| |
| BuildMI(&MBB, DL, get(Lanai::BT)).addMBB(FalseBlock); |
| return 2; |
| } |
| |
| unsigned LanaiInstrInfo::removeBranch(MachineBasicBlock &MBB, |
| int *BytesRemoved) const { |
| assert(!BytesRemoved && "code size not handled"); |
| |
| MachineBasicBlock::iterator Instruction = MBB.end(); |
| unsigned Count = 0; |
| |
| while (Instruction != MBB.begin()) { |
| --Instruction; |
| if (Instruction->isDebugInstr()) |
| continue; |
| if (Instruction->getOpcode() != Lanai::BT && |
| Instruction->getOpcode() != Lanai::BRCC) { |
| break; |
| } |
| |
| // Remove the branch. |
| Instruction->eraseFromParent(); |
| Instruction = MBB.end(); |
| ++Count; |
| } |
| |
| return Count; |
| } |
| |
| unsigned LanaiInstrInfo::isLoadFromStackSlot(const MachineInstr &MI, |
| int &FrameIndex) const { |
| if (MI.getOpcode() == Lanai::LDW_RI) |
| if (MI.getOperand(1).isFI() && MI.getOperand(2).isImm() && |
| MI.getOperand(2).getImm() == 0) { |
| FrameIndex = MI.getOperand(1).getIndex(); |
| return MI.getOperand(0).getReg(); |
| } |
| return 0; |
| } |
| |
| unsigned LanaiInstrInfo::isLoadFromStackSlotPostFE(const MachineInstr &MI, |
| int &FrameIndex) const { |
| if (MI.getOpcode() == Lanai::LDW_RI) { |
| unsigned Reg; |
| if ((Reg = isLoadFromStackSlot(MI, FrameIndex))) |
| return Reg; |
| // Check for post-frame index elimination operations |
| SmallVector<const MachineMemOperand *, 1> Accesses; |
| if (hasLoadFromStackSlot(MI, Accesses)){ |
| FrameIndex = |
| cast<FixedStackPseudoSourceValue>(Accesses.front()->getPseudoValue()) |
| ->getFrameIndex(); |
| return 1; |
| } |
| } |
| return 0; |
| } |
| |
| unsigned LanaiInstrInfo::isStoreToStackSlot(const MachineInstr &MI, |
| int &FrameIndex) const { |
| if (MI.getOpcode() == Lanai::SW_RI) |
| if (MI.getOperand(0).isFI() && MI.getOperand(1).isImm() && |
| MI.getOperand(1).getImm() == 0) { |
| FrameIndex = MI.getOperand(0).getIndex(); |
| return MI.getOperand(2).getReg(); |
| } |
| return 0; |
| } |
| |
| bool LanaiInstrInfo::getMemOperandWithOffsetWidth( |
| const MachineInstr &LdSt, const MachineOperand *&BaseOp, int64_t &Offset, |
| unsigned &Width, const TargetRegisterInfo * /*TRI*/) const { |
| // Handle only loads/stores with base register followed by immediate offset |
| // and with add as ALU op. |
| if (LdSt.getNumOperands() != 4) |
| return false; |
| if (!LdSt.getOperand(1).isReg() || !LdSt.getOperand(2).isImm() || |
| !(LdSt.getOperand(3).isImm() && LdSt.getOperand(3).getImm() == LPAC::ADD)) |
| return false; |
| |
| switch (LdSt.getOpcode()) { |
| default: |
| return false; |
| case Lanai::LDW_RI: |
| case Lanai::LDW_RR: |
| case Lanai::SW_RR: |
| case Lanai::SW_RI: |
| Width = 4; |
| break; |
| case Lanai::LDHs_RI: |
| case Lanai::LDHz_RI: |
| case Lanai::STH_RI: |
| Width = 2; |
| break; |
| case Lanai::LDBs_RI: |
| case Lanai::LDBz_RI: |
| case Lanai::STB_RI: |
| Width = 1; |
| break; |
| } |
| |
| BaseOp = &LdSt.getOperand(1); |
| Offset = LdSt.getOperand(2).getImm(); |
| |
| if (!BaseOp->isReg()) |
| return false; |
| |
| return true; |
| } |
| |
| bool LanaiInstrInfo::getMemOperandsWithOffsetWidth( |
| const MachineInstr &LdSt, SmallVectorImpl<const MachineOperand *> &BaseOps, |
| int64_t &Offset, bool &OffsetIsScalable, unsigned &Width, |
| const TargetRegisterInfo *TRI) const { |
| switch (LdSt.getOpcode()) { |
| default: |
| return false; |
| case Lanai::LDW_RI: |
| case Lanai::LDW_RR: |
| case Lanai::SW_RR: |
| case Lanai::SW_RI: |
| case Lanai::LDHs_RI: |
| case Lanai::LDHz_RI: |
| case Lanai::STH_RI: |
| case Lanai::LDBs_RI: |
| case Lanai::LDBz_RI: |
| const MachineOperand *BaseOp; |
| OffsetIsScalable = false; |
| if (!getMemOperandWithOffsetWidth(LdSt, BaseOp, Offset, Width, TRI)) |
| return false; |
| BaseOps.push_back(BaseOp); |
| return true; |
| } |
| } |
