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llvm-project/llvm/lib/Target/Lanai/LanaiInstrInfo.cpp

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//===-- 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/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.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, int &CmpMask,
int &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, int 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, int /*CmpMask*/,
int 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 (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
SE = MBB->succ_end();
SI != SE; ++SI)
if ((*SI)->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 (unsigned i = 1, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
// 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;
}
}
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