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llvm-project/llvm/lib/Target/ARM/ARMInstructionSelector.cpp

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//===- ARMInstructionSelector.cpp ----------------------------*- 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
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements the targeting of the InstructionSelector class for ARM.
/// \todo This should be generated by TableGen.
//===----------------------------------------------------------------------===//
#include "ARMRegisterBankInfo.h"
#include "ARMSubtarget.h"
#include "ARMTargetMachine.h"
#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
#include "llvm/CodeGen/GlobalISel/InstructionSelectorImpl.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/IntrinsicsARM.h"
#include "llvm/Support/Debug.h"
#define DEBUG_TYPE "arm-isel"
using namespace llvm;
namespace {
#define GET_GLOBALISEL_PREDICATE_BITSET
#include "ARMGenGlobalISel.inc"
#undef GET_GLOBALISEL_PREDICATE_BITSET
class ARMInstructionSelector : public InstructionSelector {
public:
ARMInstructionSelector(const ARMBaseTargetMachine &TM, const ARMSubtarget &STI,
const ARMRegisterBankInfo &RBI);
bool select(MachineInstr &I) override;
static const char *getName() { return DEBUG_TYPE; }
private:
bool selectImpl(MachineInstr &I, CodeGenCoverage &CoverageInfo) const;
struct CmpConstants;
struct InsertInfo;
bool selectCmp(CmpConstants Helper, MachineInstrBuilder &MIB,
MachineRegisterInfo &MRI) const;
// Helper for inserting a comparison sequence that sets \p ResReg to either 1
// if \p LHSReg and \p RHSReg are in the relationship defined by \p Cond, or
// \p PrevRes otherwise. In essence, it computes PrevRes OR (LHS Cond RHS).
bool insertComparison(CmpConstants Helper, InsertInfo I, unsigned ResReg,
ARMCC::CondCodes Cond, unsigned LHSReg, unsigned RHSReg,
unsigned PrevRes) const;
// Set \p DestReg to \p Constant.
void putConstant(InsertInfo I, unsigned DestReg, unsigned Constant) const;
bool selectGlobal(MachineInstrBuilder &MIB, MachineRegisterInfo &MRI) const;
bool selectSelect(MachineInstrBuilder &MIB, MachineRegisterInfo &MRI) const;
bool selectShift(unsigned ShiftOpc, MachineInstrBuilder &MIB) const;
// Check if the types match and both operands have the expected size and
// register bank.
bool validOpRegPair(MachineRegisterInfo &MRI, unsigned LHS, unsigned RHS,
unsigned ExpectedSize, unsigned ExpectedRegBankID) const;
// Check if the register has the expected size and register bank.
bool validReg(MachineRegisterInfo &MRI, unsigned Reg, unsigned ExpectedSize,
unsigned ExpectedRegBankID) const;
const ARMBaseInstrInfo &TII;
const ARMBaseRegisterInfo &TRI;
const ARMBaseTargetMachine &TM;
const ARMRegisterBankInfo &RBI;
const ARMSubtarget &STI;
// FIXME: This is necessary because DAGISel uses "Subtarget->" and GlobalISel
// uses "STI." in the code generated by TableGen. If we want to reuse some of
// the custom C++ predicates written for DAGISel, we need to have both around.
const ARMSubtarget *Subtarget = &STI;
// Store the opcodes that we might need, so we don't have to check what kind
// of subtarget (ARM vs Thumb) we have all the time.
struct OpcodeCache {
unsigned ZEXT16;
unsigned SEXT16;
unsigned ZEXT8;
unsigned SEXT8;
// Used for implementing ZEXT/SEXT from i1
unsigned AND;
unsigned RSB;
unsigned STORE32;
unsigned LOAD32;
unsigned STORE16;
unsigned LOAD16;
unsigned STORE8;
unsigned LOAD8;
unsigned ADDrr;
unsigned ADDri;
// Used for G_ICMP
unsigned CMPrr;
unsigned MOVi;
unsigned MOVCCi;
// Used for G_SELECT
unsigned MOVCCr;
unsigned TSTri;
unsigned Bcc;
// Used for G_GLOBAL_VALUE
unsigned MOVi32imm;
unsigned ConstPoolLoad;
unsigned MOV_ga_pcrel;
unsigned LDRLIT_ga_pcrel;
unsigned LDRLIT_ga_abs;
OpcodeCache(const ARMSubtarget &STI);
} const Opcodes;
// Select the opcode for simple extensions (that translate to a single SXT/UXT
// instruction). Extension operations more complicated than that should not
// invoke this. Returns the original opcode if it doesn't know how to select a
// better one.
unsigned selectSimpleExtOpc(unsigned Opc, unsigned Size) const;
// Select the opcode for simple loads and stores. Returns the original opcode
// if it doesn't know how to select a better one.
unsigned selectLoadStoreOpCode(unsigned Opc, unsigned RegBank,
unsigned Size) const;
void renderVFPF32Imm(MachineInstrBuilder &New, const MachineInstr &Old,
int OpIdx = -1) const;
void renderVFPF64Imm(MachineInstrBuilder &New, const MachineInstr &Old,
int OpIdx = -1) const;
#define GET_GLOBALISEL_PREDICATES_DECL
#include "ARMGenGlobalISel.inc"
#undef GET_GLOBALISEL_PREDICATES_DECL
// We declare the temporaries used by selectImpl() in the class to minimize the
// cost of constructing placeholder values.
#define GET_GLOBALISEL_TEMPORARIES_DECL
#include "ARMGenGlobalISel.inc"
#undef GET_GLOBALISEL_TEMPORARIES_DECL
};
} // end anonymous namespace
namespace llvm {
InstructionSelector *
createARMInstructionSelector(const ARMBaseTargetMachine &TM,
const ARMSubtarget &STI,
const ARMRegisterBankInfo &RBI) {
return new ARMInstructionSelector(TM, STI, RBI);
}
}
#define GET_GLOBALISEL_IMPL
#include "ARMGenGlobalISel.inc"
#undef GET_GLOBALISEL_IMPL
ARMInstructionSelector::ARMInstructionSelector(const ARMBaseTargetMachine &TM,
const ARMSubtarget &STI,
const ARMRegisterBankInfo &RBI)
: InstructionSelector(), TII(*STI.getInstrInfo()),
TRI(*STI.getRegisterInfo()), TM(TM), RBI(RBI), STI(STI), Opcodes(STI),
#define GET_GLOBALISEL_PREDICATES_INIT
#include "ARMGenGlobalISel.inc"
#undef GET_GLOBALISEL_PREDICATES_INIT
#define GET_GLOBALISEL_TEMPORARIES_INIT
#include "ARMGenGlobalISel.inc"
#undef GET_GLOBALISEL_TEMPORARIES_INIT
{
}
static const TargetRegisterClass *guessRegClass(unsigned Reg,
MachineRegisterInfo &MRI,
const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) {
const RegisterBank *RegBank = RBI.getRegBank(Reg, MRI, TRI);
assert(RegBank && "Can't get reg bank for virtual register");
const unsigned Size = MRI.getType(Reg).getSizeInBits();
assert((RegBank->getID() == ARM::GPRRegBankID ||
RegBank->getID() == ARM::FPRRegBankID) &&
"Unsupported reg bank");
if (RegBank->getID() == ARM::FPRRegBankID) {
if (Size == 32)
return &ARM::SPRRegClass;
else if (Size == 64)
return &ARM::DPRRegClass;
else if (Size == 128)
return &ARM::QPRRegClass;
else
llvm_unreachable("Unsupported destination size");
}
return &ARM::GPRRegClass;
}
static bool selectCopy(MachineInstr &I, const TargetInstrInfo &TII,
MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) {
Register DstReg = I.getOperand(0).getReg();
if (Register::isPhysicalRegister(DstReg))
return true;
const TargetRegisterClass *RC = guessRegClass(DstReg, MRI, TRI, RBI);
// No need to constrain SrcReg. It will get constrained when
// we hit another of its uses or its defs.
// Copies do not have constraints.
if (!RBI.constrainGenericRegister(DstReg, *RC, MRI)) {
LLVM_DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())
<< " operand\n");
return false;
}
return true;
}
static bool selectMergeValues(MachineInstrBuilder &MIB,
const ARMBaseInstrInfo &TII,
MachineRegisterInfo &MRI,
const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) {
assert(TII.getSubtarget().hasVFP2Base() && "Can't select merge without VFP");
// We only support G_MERGE_VALUES as a way to stick together two scalar GPRs
// into one DPR.
Register VReg0 = MIB.getReg(0);
(void)VReg0;
assert(MRI.getType(VReg0).getSizeInBits() == 64 &&
RBI.getRegBank(VReg0, MRI, TRI)->getID() == ARM::FPRRegBankID &&
"Unsupported operand for G_MERGE_VALUES");
Register VReg1 = MIB.getReg(1);
(void)VReg1;
assert(MRI.getType(VReg1).getSizeInBits() == 32 &&
RBI.getRegBank(VReg1, MRI, TRI)->getID() == ARM::GPRRegBankID &&
"Unsupported operand for G_MERGE_VALUES");
Register VReg2 = MIB.getReg(2);
(void)VReg2;
assert(MRI.getType(VReg2).getSizeInBits() == 32 &&
RBI.getRegBank(VReg2, MRI, TRI)->getID() == ARM::GPRRegBankID &&
"Unsupported operand for G_MERGE_VALUES");
MIB->setDesc(TII.get(ARM::VMOVDRR));
MIB.add(predOps(ARMCC::AL));
return true;
}
static bool selectUnmergeValues(MachineInstrBuilder &MIB,
const ARMBaseInstrInfo &TII,
MachineRegisterInfo &MRI,
const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) {
assert(TII.getSubtarget().hasVFP2Base() &&
"Can't select unmerge without VFP");
// We only support G_UNMERGE_VALUES as a way to break up one DPR into two
// GPRs.
Register VReg0 = MIB.getReg(0);
(void)VReg0;
assert(MRI.getType(VReg0).getSizeInBits() == 32 &&
RBI.getRegBank(VReg0, MRI, TRI)->getID() == ARM::GPRRegBankID &&
"Unsupported operand for G_UNMERGE_VALUES");
Register VReg1 = MIB.getReg(1);
(void)VReg1;
assert(MRI.getType(VReg1).getSizeInBits() == 32 &&
RBI.getRegBank(VReg1, MRI, TRI)->getID() == ARM::GPRRegBankID &&
"Unsupported operand for G_UNMERGE_VALUES");
Register VReg2 = MIB.getReg(2);
(void)VReg2;
assert(MRI.getType(VReg2).getSizeInBits() == 64 &&
RBI.getRegBank(VReg2, MRI, TRI)->getID() == ARM::FPRRegBankID &&
"Unsupported operand for G_UNMERGE_VALUES");
MIB->setDesc(TII.get(ARM::VMOVRRD));
MIB.add(predOps(ARMCC::AL));
return true;
}
ARMInstructionSelector::OpcodeCache::OpcodeCache(const ARMSubtarget &STI) {
bool isThumb = STI.isThumb();
using namespace TargetOpcode;
#define STORE_OPCODE(VAR, OPC) VAR = isThumb ? ARM::t2##OPC : ARM::OPC
STORE_OPCODE(SEXT16, SXTH);
STORE_OPCODE(ZEXT16, UXTH);
STORE_OPCODE(SEXT8, SXTB);
STORE_OPCODE(ZEXT8, UXTB);
STORE_OPCODE(AND, ANDri);
STORE_OPCODE(RSB, RSBri);
STORE_OPCODE(STORE32, STRi12);
STORE_OPCODE(LOAD32, LDRi12);
// LDRH/STRH are special...
STORE16 = isThumb ? ARM::t2STRHi12 : ARM::STRH;
LOAD16 = isThumb ? ARM::t2LDRHi12 : ARM::LDRH;
STORE_OPCODE(STORE8, STRBi12);
STORE_OPCODE(LOAD8, LDRBi12);
STORE_OPCODE(ADDrr, ADDrr);
STORE_OPCODE(ADDri, ADDri);
STORE_OPCODE(CMPrr, CMPrr);
STORE_OPCODE(MOVi, MOVi);
STORE_OPCODE(MOVCCi, MOVCCi);
STORE_OPCODE(MOVCCr, MOVCCr);
STORE_OPCODE(TSTri, TSTri);
STORE_OPCODE(Bcc, Bcc);
STORE_OPCODE(MOVi32imm, MOVi32imm);
ConstPoolLoad = isThumb ? ARM::t2LDRpci : ARM::LDRi12;
STORE_OPCODE(MOV_ga_pcrel, MOV_ga_pcrel);
LDRLIT_ga_pcrel = isThumb ? ARM::tLDRLIT_ga_pcrel : ARM::LDRLIT_ga_pcrel;
LDRLIT_ga_abs = isThumb ? ARM::tLDRLIT_ga_abs : ARM::LDRLIT_ga_abs;
#undef MAP_OPCODE
}
unsigned ARMInstructionSelector::selectSimpleExtOpc(unsigned Opc,
unsigned Size) const {
using namespace TargetOpcode;
if (Size != 8 && Size != 16)
return Opc;
if (Opc == G_SEXT)
return Size == 8 ? Opcodes.SEXT8 : Opcodes.SEXT16;
if (Opc == G_ZEXT)
return Size == 8 ? Opcodes.ZEXT8 : Opcodes.ZEXT16;
return Opc;
}
unsigned ARMInstructionSelector::selectLoadStoreOpCode(unsigned Opc,
unsigned RegBank,
unsigned Size) const {
bool isStore = Opc == TargetOpcode::G_STORE;
if (RegBank == ARM::GPRRegBankID) {
switch (Size) {
case 1:
case 8:
return isStore ? Opcodes.STORE8 : Opcodes.LOAD8;
case 16:
return isStore ? Opcodes.STORE16 : Opcodes.LOAD16;
case 32:
return isStore ? Opcodes.STORE32 : Opcodes.LOAD32;
default:
return Opc;
}
}
if (RegBank == ARM::FPRRegBankID) {
switch (Size) {
case 32:
return isStore ? ARM::VSTRS : ARM::VLDRS;
case 64:
return isStore ? ARM::VSTRD : ARM::VLDRD;
default:
return Opc;
}
}
return Opc;
}
// When lowering comparisons, we sometimes need to perform two compares instead
// of just one. Get the condition codes for both comparisons. If only one is
// needed, the second member of the pair is ARMCC::AL.
static std::pair<ARMCC::CondCodes, ARMCC::CondCodes>
getComparePreds(CmpInst::Predicate Pred) {
std::pair<ARMCC::CondCodes, ARMCC::CondCodes> Preds = {ARMCC::AL, ARMCC::AL};
switch (Pred) {
case CmpInst::FCMP_ONE:
Preds = {ARMCC::GT, ARMCC::MI};
break;
case CmpInst::FCMP_UEQ:
Preds = {ARMCC::EQ, ARMCC::VS};
break;
case CmpInst::ICMP_EQ:
case CmpInst::FCMP_OEQ:
Preds.first = ARMCC::EQ;
break;
case CmpInst::ICMP_SGT:
case CmpInst::FCMP_OGT:
Preds.first = ARMCC::GT;
break;
case CmpInst::ICMP_SGE:
case CmpInst::FCMP_OGE:
Preds.first = ARMCC::GE;
break;
case CmpInst::ICMP_UGT:
case CmpInst::FCMP_UGT:
Preds.first = ARMCC::HI;
break;
case CmpInst::FCMP_OLT:
Preds.first = ARMCC::MI;
break;
case CmpInst::ICMP_ULE:
case CmpInst::FCMP_OLE:
Preds.first = ARMCC::LS;
break;
case CmpInst::FCMP_ORD:
Preds.first = ARMCC::VC;
break;
case CmpInst::FCMP_UNO:
Preds.first = ARMCC::VS;
break;
case CmpInst::FCMP_UGE:
Preds.first = ARMCC::PL;
break;
case CmpInst::ICMP_SLT:
case CmpInst::FCMP_ULT:
Preds.first = ARMCC::LT;
break;
case CmpInst::ICMP_SLE:
case CmpInst::FCMP_ULE:
Preds.first = ARMCC::LE;
break;
case CmpInst::FCMP_UNE:
case CmpInst::ICMP_NE:
Preds.first = ARMCC::NE;
break;
case CmpInst::ICMP_UGE:
Preds.first = ARMCC::HS;
break;
case CmpInst::ICMP_ULT:
Preds.first = ARMCC::LO;
break;
default:
break;
}
assert(Preds.first != ARMCC::AL && "No comparisons needed?");
return Preds;
}
struct ARMInstructionSelector::CmpConstants {
CmpConstants(unsigned CmpOpcode, unsigned FlagsOpcode, unsigned SelectOpcode,
unsigned OpRegBank, unsigned OpSize)
: ComparisonOpcode(CmpOpcode), ReadFlagsOpcode(FlagsOpcode),
SelectResultOpcode(SelectOpcode), OperandRegBankID(OpRegBank),
OperandSize(OpSize) {}
// The opcode used for performing the comparison.
const unsigned ComparisonOpcode;
// The opcode used for reading the flags set by the comparison. May be
// ARM::INSTRUCTION_LIST_END if we don't need to read the flags.
const unsigned ReadFlagsOpcode;
// The opcode used for materializing the result of the comparison.
const unsigned SelectResultOpcode;
// The assumed register bank ID for the operands.
const unsigned OperandRegBankID;
// The assumed size in bits for the operands.
const unsigned OperandSize;
};
struct ARMInstructionSelector::InsertInfo {
InsertInfo(MachineInstrBuilder &MIB)
: MBB(*MIB->getParent()), InsertBefore(std::next(MIB->getIterator())),
DbgLoc(MIB->getDebugLoc()) {}
MachineBasicBlock &MBB;
const MachineBasicBlock::instr_iterator InsertBefore;
const DebugLoc &DbgLoc;
};
void ARMInstructionSelector::putConstant(InsertInfo I, unsigned DestReg,
unsigned Constant) const {
(void)BuildMI(I.MBB, I.InsertBefore, I.DbgLoc, TII.get(Opcodes.MOVi))
.addDef(DestReg)
.addImm(Constant)
.add(predOps(ARMCC::AL))
.add(condCodeOp());
}
bool ARMInstructionSelector::validOpRegPair(MachineRegisterInfo &MRI,
unsigned LHSReg, unsigned RHSReg,
unsigned ExpectedSize,
unsigned ExpectedRegBankID) const {
return MRI.getType(LHSReg) == MRI.getType(RHSReg) &&
validReg(MRI, LHSReg, ExpectedSize, ExpectedRegBankID) &&
validReg(MRI, RHSReg, ExpectedSize, ExpectedRegBankID);
}
bool ARMInstructionSelector::validReg(MachineRegisterInfo &MRI, unsigned Reg,
unsigned ExpectedSize,
unsigned ExpectedRegBankID) const {
if (MRI.getType(Reg).getSizeInBits() != ExpectedSize) {
LLVM_DEBUG(dbgs() << "Unexpected size for register");
return false;
}
if (RBI.getRegBank(Reg, MRI, TRI)->getID() != ExpectedRegBankID) {
LLVM_DEBUG(dbgs() << "Unexpected register bank for register");
return false;
}
return true;
}
bool ARMInstructionSelector::selectCmp(CmpConstants Helper,
MachineInstrBuilder &MIB,
MachineRegisterInfo &MRI) const {
const InsertInfo I(MIB);
auto ResReg = MIB.getReg(0);
if (!validReg(MRI, ResReg, 1, ARM::GPRRegBankID))
return false;
auto Cond =
static_cast<CmpInst::Predicate>(MIB->getOperand(1).getPredicate());
if (Cond == CmpInst::FCMP_TRUE || Cond == CmpInst::FCMP_FALSE) {
putConstant(I, ResReg, Cond == CmpInst::FCMP_TRUE ? 1 : 0);
MIB->eraseFromParent();
return true;
}
auto LHSReg = MIB.getReg(2);
auto RHSReg = MIB.getReg(3);
if (!validOpRegPair(MRI, LHSReg, RHSReg, Helper.OperandSize,
Helper.OperandRegBankID))
return false;
auto ARMConds = getComparePreds(Cond);
auto ZeroReg = MRI.createVirtualRegister(&ARM::GPRRegClass);
putConstant(I, ZeroReg, 0);
if (ARMConds.second == ARMCC::AL) {
// Simple case, we only need one comparison and we're done.
if (!insertComparison(Helper, I, ResReg, ARMConds.first, LHSReg, RHSReg,
ZeroReg))
return false;
} else {
// Not so simple, we need two successive comparisons.
auto IntermediateRes = MRI.createVirtualRegister(&ARM::GPRRegClass);
if (!insertComparison(Helper, I, IntermediateRes, ARMConds.first, LHSReg,
RHSReg, ZeroReg))
return false;
if (!insertComparison(Helper, I, ResReg, ARMConds.second, LHSReg, RHSReg,
IntermediateRes))
return false;
}
MIB->eraseFromParent();
return true;
}
bool ARMInstructionSelector::insertComparison(CmpConstants Helper, InsertInfo I,
unsigned ResReg,
ARMCC::CondCodes Cond,
unsigned LHSReg, unsigned RHSReg,
unsigned PrevRes) const {
// Perform the comparison.
auto CmpI =
BuildMI(I.MBB, I.InsertBefore, I.DbgLoc, TII.get(Helper.ComparisonOpcode))
.addUse(LHSReg)
.addUse(RHSReg)
.add(predOps(ARMCC::AL));
if (!constrainSelectedInstRegOperands(*CmpI, TII, TRI, RBI))
return false;
// Read the comparison flags (if necessary).
if (Helper.ReadFlagsOpcode != ARM::INSTRUCTION_LIST_END) {
auto ReadI = BuildMI(I.MBB, I.InsertBefore, I.DbgLoc,
TII.get(Helper.ReadFlagsOpcode))
.add(predOps(ARMCC::AL));
if (!constrainSelectedInstRegOperands(*ReadI, TII, TRI, RBI))
return false;
}
// Select either 1 or the previous result based on the value of the flags.
auto Mov1I = BuildMI(I.MBB, I.InsertBefore, I.DbgLoc,
TII.get(Helper.SelectResultOpcode))
.addDef(ResReg)
.addUse(PrevRes)
.addImm(1)
.add(predOps(Cond, ARM::CPSR));
if (!constrainSelectedInstRegOperands(*Mov1I, TII, TRI, RBI))
return false;
return true;
}
bool ARMInstructionSelector::selectGlobal(MachineInstrBuilder &MIB,
MachineRegisterInfo &MRI) const {
if ((STI.isROPI() || STI.isRWPI()) && !STI.isTargetELF()) {
LLVM_DEBUG(dbgs() << "ROPI and RWPI only supported for ELF\n");
return false;
}
auto GV = MIB->getOperand(1).getGlobal();
if (GV->isThreadLocal()) {
LLVM_DEBUG(dbgs() << "TLS variables not supported yet\n");
return false;
}
auto &MBB = *MIB->getParent();
auto &MF = *MBB.getParent();
bool UseMovt = STI.useMovt();
unsigned Size = TM.getPointerSize(0);
const Align Alignment(4);
auto addOpsForConstantPoolLoad = [&MF, Alignment,
Size](MachineInstrBuilder &MIB,
const GlobalValue *GV, bool IsSBREL) {
assert((MIB->getOpcode() == ARM::LDRi12 ||
MIB->getOpcode() == ARM::t2LDRpci) &&
"Unsupported instruction");
auto ConstPool = MF.getConstantPool();
auto CPIndex =
// For SB relative entries we need a target-specific constant pool.
// Otherwise, just use a regular constant pool entry.
IsSBREL
? ConstPool->getConstantPoolIndex(
ARMConstantPoolConstant::Create(GV, ARMCP::SBREL), Alignment)
: ConstPool->getConstantPoolIndex(GV, Alignment);
MIB.addConstantPoolIndex(CPIndex, /*Offset*/ 0, /*TargetFlags*/ 0)
.addMemOperand(MF.getMachineMemOperand(
MachinePointerInfo::getConstantPool(MF), MachineMemOperand::MOLoad,
Size, Alignment));
if (MIB->getOpcode() == ARM::LDRi12)
MIB.addImm(0);
MIB.add(predOps(ARMCC::AL));
};
auto addGOTMemOperand = [this, &MF, Alignment](MachineInstrBuilder &MIB) {
MIB.addMemOperand(MF.getMachineMemOperand(
MachinePointerInfo::getGOT(MF), MachineMemOperand::MOLoad,
TM.getProgramPointerSize(), Alignment));
};
if (TM.isPositionIndependent()) {
bool Indirect = STI.isGVIndirectSymbol(GV);
// For ARM mode, we have different pseudoinstructions for direct accesses
// and indirect accesses, and the ones for indirect accesses include the
// load from GOT. For Thumb mode, we use the same pseudoinstruction for both
// direct and indirect accesses, and we need to manually generate the load
// from GOT.
bool UseOpcodeThatLoads = Indirect && !STI.isThumb();
// FIXME: Taking advantage of MOVT for ELF is pretty involved, so we don't
// support it yet. See PR28229.
unsigned Opc =
UseMovt && !STI.isTargetELF()
? (UseOpcodeThatLoads ? (unsigned)ARM::MOV_ga_pcrel_ldr
: Opcodes.MOV_ga_pcrel)
: (UseOpcodeThatLoads ? (unsigned)ARM::LDRLIT_ga_pcrel_ldr
: Opcodes.LDRLIT_ga_pcrel);
MIB->setDesc(TII.get(Opc));
int TargetFlags = ARMII::MO_NO_FLAG;
if (STI.isTargetDarwin())
TargetFlags |= ARMII::MO_NONLAZY;
if (STI.isGVInGOT(GV))
TargetFlags |= ARMII::MO_GOT;
MIB->getOperand(1).setTargetFlags(TargetFlags);
if (Indirect) {
if (!UseOpcodeThatLoads) {
auto ResultReg = MIB.getReg(0);
auto AddressReg = MRI.createVirtualRegister(&ARM::GPRRegClass);
MIB->getOperand(0).setReg(AddressReg);
auto InsertBefore = std::next(MIB->getIterator());
auto MIBLoad = BuildMI(MBB, InsertBefore, MIB->getDebugLoc(),
TII.get(Opcodes.LOAD32))
.addDef(ResultReg)
.addReg(AddressReg)
.addImm(0)
.add(predOps(ARMCC::AL));
addGOTMemOperand(MIBLoad);
if (!constrainSelectedInstRegOperands(*MIBLoad, TII, TRI, RBI))
return false;
} else {
addGOTMemOperand(MIB);
}
}
return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);
}
bool isReadOnly = STI.getTargetLowering()->isReadOnly(GV);
if (STI.isROPI() && isReadOnly) {
unsigned Opc = UseMovt ? Opcodes.MOV_ga_pcrel : Opcodes.LDRLIT_ga_pcrel;
MIB->setDesc(TII.get(Opc));
return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);
}
if (STI.isRWPI() && !isReadOnly) {
auto Offset = MRI.createVirtualRegister(&ARM::GPRRegClass);
MachineInstrBuilder OffsetMIB;
if (UseMovt) {
OffsetMIB = BuildMI(MBB, *MIB, MIB->getDebugLoc(),
TII.get(Opcodes.MOVi32imm), Offset);
OffsetMIB.addGlobalAddress(GV, /*Offset*/ 0, ARMII::MO_SBREL);
} else {
// Load the offset from the constant pool.
OffsetMIB = BuildMI(MBB, *MIB, MIB->getDebugLoc(),
TII.get(Opcodes.ConstPoolLoad), Offset);
addOpsForConstantPoolLoad(OffsetMIB, GV, /*IsSBREL*/ true);
}
if (!constrainSelectedInstRegOperands(*OffsetMIB, TII, TRI, RBI))
return false;
// Add the offset to the SB register.
MIB->setDesc(TII.get(Opcodes.ADDrr));
MIB->RemoveOperand(1);
MIB.addReg(ARM::R9) // FIXME: don't hardcode R9
.addReg(Offset)
.add(predOps(ARMCC::AL))
.add(condCodeOp());
return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);
}
if (STI.isTargetELF()) {
if (UseMovt) {
MIB->setDesc(TII.get(Opcodes.MOVi32imm));
} else {
// Load the global's address from the constant pool.
MIB->setDesc(TII.get(Opcodes.ConstPoolLoad));
MIB->RemoveOperand(1);
addOpsForConstantPoolLoad(MIB, GV, /*IsSBREL*/ false);
}
} else if (STI.isTargetMachO()) {
if (UseMovt)
MIB->setDesc(TII.get(Opcodes.MOVi32imm));
else
MIB->setDesc(TII.get(Opcodes.LDRLIT_ga_abs));
} else {
LLVM_DEBUG(dbgs() << "Object format not supported yet\n");
return false;
}
return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);
}
bool ARMInstructionSelector::selectSelect(MachineInstrBuilder &MIB,
MachineRegisterInfo &MRI) const {
auto &MBB = *MIB->getParent();
auto InsertBefore = std::next(MIB->getIterator());
auto &DbgLoc = MIB->getDebugLoc();
// Compare the condition to 1.
auto CondReg = MIB.getReg(1);
assert(validReg(MRI, CondReg, 1, ARM::GPRRegBankID) &&
"Unsupported types for select operation");
auto CmpI = BuildMI(MBB, InsertBefore, DbgLoc, TII.get(Opcodes.TSTri))
.addUse(CondReg)
.addImm(1)
.add(predOps(ARMCC::AL));
if (!constrainSelectedInstRegOperands(*CmpI, TII, TRI, RBI))
return false;
// Move a value into the result register based on the result of the
// comparison.
auto ResReg = MIB.getReg(0);
auto TrueReg = MIB.getReg(2);
auto FalseReg = MIB.getReg(3);
assert(validOpRegPair(MRI, ResReg, TrueReg, 32, ARM::GPRRegBankID) &&
validOpRegPair(MRI, TrueReg, FalseReg, 32, ARM::GPRRegBankID) &&
"Unsupported types for select operation");
auto Mov1I = BuildMI(MBB, InsertBefore, DbgLoc, TII.get(Opcodes.MOVCCr))
.addDef(ResReg)
.addUse(TrueReg)
.addUse(FalseReg)
.add(predOps(ARMCC::EQ, ARM::CPSR));
if (!constrainSelectedInstRegOperands(*Mov1I, TII, TRI, RBI))
return false;
MIB->eraseFromParent();
return true;
}
bool ARMInstructionSelector::selectShift(unsigned ShiftOpc,
MachineInstrBuilder &MIB) const {
assert(!STI.isThumb() && "Unsupported subtarget");
MIB->setDesc(TII.get(ARM::MOVsr));
MIB.addImm(ShiftOpc);
MIB.add(predOps(ARMCC::AL)).add(condCodeOp());
return constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);
}
void ARMInstructionSelector::renderVFPF32Imm(
MachineInstrBuilder &NewInstBuilder, const MachineInstr &OldInst,
int OpIdx) const {
assert(OldInst.getOpcode() == TargetOpcode::G_FCONSTANT &&
OpIdx == -1 && "Expected G_FCONSTANT");
APFloat FPImmValue = OldInst.getOperand(1).getFPImm()->getValueAPF();
int FPImmEncoding = ARM_AM::getFP32Imm(FPImmValue);
assert(FPImmEncoding != -1 && "Invalid immediate value");
NewInstBuilder.addImm(FPImmEncoding);
}
void ARMInstructionSelector::renderVFPF64Imm(
MachineInstrBuilder &NewInstBuilder, const MachineInstr &OldInst, int OpIdx) const {
assert(OldInst.getOpcode() == TargetOpcode::G_FCONSTANT &&
OpIdx == -1 && "Expected G_FCONSTANT");
APFloat FPImmValue = OldInst.getOperand(1).getFPImm()->getValueAPF();
int FPImmEncoding = ARM_AM::getFP64Imm(FPImmValue);
assert(FPImmEncoding != -1 && "Invalid immediate value");
NewInstBuilder.addImm(FPImmEncoding);
}
bool ARMInstructionSelector::select(MachineInstr &I) {
assert(I.getParent() && "Instruction should be in a basic block!");
assert(I.getParent()->getParent() && "Instruction should be in a function!");
auto &MBB = *I.getParent();
auto &MF = *MBB.getParent();
auto &MRI = MF.getRegInfo();
if (!isPreISelGenericOpcode(I.getOpcode())) {
if (I.isCopy())
return selectCopy(I, TII, MRI, TRI, RBI);
return true;
}
using namespace TargetOpcode;
if (selectImpl(I, *CoverageInfo))
return true;
MachineInstrBuilder MIB{MF, I};
bool isSExt = false;
switch (I.getOpcode()) {
case G_SEXT:
isSExt = true;
LLVM_FALLTHROUGH;
case G_ZEXT: {
assert(MRI.getType(I.getOperand(0).getReg()).getSizeInBits() <= 32 &&
"Unsupported destination size for extension");
LLT SrcTy = MRI.getType(I.getOperand(1).getReg());
unsigned SrcSize = SrcTy.getSizeInBits();
switch (SrcSize) {
case 1: {
// ZExt boils down to & 0x1; for SExt we also subtract that from 0
I.setDesc(TII.get(Opcodes.AND));
MIB.addImm(1).add(predOps(ARMCC::AL)).add(condCodeOp());
if (isSExt) {
Register SExtResult = I.getOperand(0).getReg();
// Use a new virtual register for the result of the AND
Register AndResult = MRI.createVirtualRegister(&ARM::GPRRegClass);
I.getOperand(0).setReg(AndResult);
auto InsertBefore = std::next(I.getIterator());
auto SubI =
BuildMI(MBB, InsertBefore, I.getDebugLoc(), TII.get(Opcodes.RSB))
.addDef(SExtResult)
.addUse(AndResult)
.addImm(0)
.add(predOps(ARMCC::AL))
.add(condCodeOp());
if (!constrainSelectedInstRegOperands(*SubI, TII, TRI, RBI))
return false;
}
break;
}
case 8:
case 16: {
unsigned NewOpc = selectSimpleExtOpc(I.getOpcode(), SrcSize);
if (NewOpc == I.getOpcode())
return false;
I.setDesc(TII.get(NewOpc));
MIB.addImm(0).add(predOps(ARMCC::AL));
break;
}
default:
LLVM_DEBUG(dbgs() << "Unsupported source size for extension");
return false;
}
break;
}
case G_ANYEXT:
case G_TRUNC: {
// The high bits are undefined, so there's nothing special to do, just
// treat it as a copy.
auto SrcReg = I.getOperand(1).getReg();
auto DstReg = I.getOperand(0).getReg();
const auto &SrcRegBank = *RBI.getRegBank(SrcReg, MRI, TRI);
const auto &DstRegBank = *RBI.getRegBank(DstReg, MRI, TRI);
if (SrcRegBank.getID() == ARM::FPRRegBankID) {
// This should only happen in the obscure case where we have put a 64-bit
// integer into a D register. Get it out of there and keep only the
// interesting part.
assert(I.getOpcode() == G_TRUNC && "Unsupported operand for G_ANYEXT");
assert(DstRegBank.getID() == ARM::GPRRegBankID &&
"Unsupported combination of register banks");
assert(MRI.getType(SrcReg).getSizeInBits() == 64 && "Unsupported size");
assert(MRI.getType(DstReg).getSizeInBits() <= 32 && "Unsupported size");
Register IgnoredBits = MRI.createVirtualRegister(&ARM::GPRRegClass);
auto InsertBefore = std::next(I.getIterator());
auto MovI =
BuildMI(MBB, InsertBefore, I.getDebugLoc(), TII.get(ARM::VMOVRRD))
.addDef(DstReg)
.addDef(IgnoredBits)
.addUse(SrcReg)
.add(predOps(ARMCC::AL));
if (!constrainSelectedInstRegOperands(*MovI, TII, TRI, RBI))
return false;
MIB->eraseFromParent();
return true;
}
if (SrcRegBank.getID() != DstRegBank.getID()) {
LLVM_DEBUG(
dbgs() << "G_TRUNC/G_ANYEXT operands on different register banks\n");
return false;
}
if (SrcRegBank.getID() != ARM::GPRRegBankID) {
LLVM_DEBUG(dbgs() << "G_TRUNC/G_ANYEXT on non-GPR not supported yet\n");
return false;
}
I.setDesc(TII.get(COPY));
return selectCopy(I, TII, MRI, TRI, RBI);
}
case G_CONSTANT: {
if (!MRI.getType(I.getOperand(0).getReg()).isPointer()) {
// Non-pointer constants should be handled by TableGen.
LLVM_DEBUG(dbgs() << "Unsupported constant type\n");
return false;
}
auto &Val = I.getOperand(1);
if (Val.isCImm()) {
if (!Val.getCImm()->isZero()) {
LLVM_DEBUG(dbgs() << "Unsupported pointer constant value\n");
return false;
}
Val.ChangeToImmediate(0);
} else {
assert(Val.isImm() && "Unexpected operand for G_CONSTANT");
if (Val.getImm() != 0) {
LLVM_DEBUG(dbgs() << "Unsupported pointer constant value\n");
return false;
}
}
assert(!STI.isThumb() && "Unsupported subtarget");
I.setDesc(TII.get(ARM::MOVi));
MIB.add(predOps(ARMCC::AL)).add(condCodeOp());
break;
}
case G_FCONSTANT: {
// Load from constant pool
unsigned Size = MRI.getType(I.getOperand(0).getReg()).getSizeInBits() / 8;
Align Alignment(Size);
assert((Size == 4 || Size == 8) && "Unsupported FP constant type");
auto LoadOpcode = Size == 4 ? ARM::VLDRS : ARM::VLDRD;
auto ConstPool = MF.getConstantPool();
auto CPIndex =
ConstPool->getConstantPoolIndex(I.getOperand(1).getFPImm(), Alignment);
MIB->setDesc(TII.get(LoadOpcode));
MIB->RemoveOperand(1);
MIB.addConstantPoolIndex(CPIndex, /*Offset*/ 0, /*TargetFlags*/ 0)
.addMemOperand(
MF.getMachineMemOperand(MachinePointerInfo::getConstantPool(MF),
MachineMemOperand::MOLoad, Size, Alignment))
.addImm(0)
.add(predOps(ARMCC::AL));
break;
}
case G_INTTOPTR:
case G_PTRTOINT: {
auto SrcReg = I.getOperand(1).getReg();
auto DstReg = I.getOperand(0).getReg();
const auto &SrcRegBank = *RBI.getRegBank(SrcReg, MRI, TRI);
const auto &DstRegBank = *RBI.getRegBank(DstReg, MRI, TRI);
if (SrcRegBank.getID() != DstRegBank.getID()) {
LLVM_DEBUG(
dbgs()
<< "G_INTTOPTR/G_PTRTOINT operands on different register banks\n");
return false;
}
if (SrcRegBank.getID() != ARM::GPRRegBankID) {
LLVM_DEBUG(
dbgs() << "G_INTTOPTR/G_PTRTOINT on non-GPR not supported yet\n");
return false;
}
I.setDesc(TII.get(COPY));
return selectCopy(I, TII, MRI, TRI, RBI);
}
case G_SELECT:
return selectSelect(MIB, MRI);
case G_ICMP: {
CmpConstants Helper(Opcodes.CMPrr, ARM::INSTRUCTION_LIST_END,
Opcodes.MOVCCi, ARM::GPRRegBankID, 32);
return selectCmp(Helper, MIB, MRI);
}
case G_FCMP: {
assert(STI.hasVFP2Base() && "Can't select fcmp without VFP");
Register OpReg = I.getOperand(2).getReg();
unsigned Size = MRI.getType(OpReg).getSizeInBits();
if (Size == 64 && !STI.hasFP64()) {
LLVM_DEBUG(dbgs() << "Subtarget only supports single precision");
return false;
}
if (Size != 32 && Size != 64) {
LLVM_DEBUG(dbgs() << "Unsupported size for G_FCMP operand");
return false;
}
CmpConstants Helper(Size == 32 ? ARM::VCMPS : ARM::VCMPD, ARM::FMSTAT,
Opcodes.MOVCCi, ARM::FPRRegBankID, Size);
return selectCmp(Helper, MIB, MRI);
}
case G_LSHR:
return selectShift(ARM_AM::ShiftOpc::lsr, MIB);
case G_ASHR:
return selectShift(ARM_AM::ShiftOpc::asr, MIB);
case G_SHL: {
return selectShift(ARM_AM::ShiftOpc::lsl, MIB);
}
case G_PTR_ADD:
I.setDesc(TII.get(Opcodes.ADDrr));
MIB.add(predOps(ARMCC::AL)).add(condCodeOp());
break;
case G_FRAME_INDEX:
// Add 0 to the given frame index and hope it will eventually be folded into
// the user(s).
I.setDesc(TII.get(Opcodes.ADDri));
MIB.addImm(0).add(predOps(ARMCC::AL)).add(condCodeOp());
break;
case G_GLOBAL_VALUE:
return selectGlobal(MIB, MRI);
case G_STORE:
case G_LOAD: {
const auto &MemOp = **I.memoperands_begin();
if (MemOp.isAtomic()) {
LLVM_DEBUG(dbgs() << "Atomic load/store not supported yet\n");
return false;
}
Register Reg = I.getOperand(0).getReg();
unsigned RegBank = RBI.getRegBank(Reg, MRI, TRI)->getID();
LLT ValTy = MRI.getType(Reg);
const auto ValSize = ValTy.getSizeInBits();
assert((ValSize != 64 || STI.hasVFP2Base()) &&
"Don't know how to load/store 64-bit value without VFP");
const auto NewOpc = selectLoadStoreOpCode(I.getOpcode(), RegBank, ValSize);
if (NewOpc == G_LOAD || NewOpc == G_STORE)
return false;
I.setDesc(TII.get(NewOpc));
if (NewOpc == ARM::LDRH || NewOpc == ARM::STRH)
// LDRH has a funny addressing mode (there's already a FIXME for it).
MIB.addReg(0);
MIB.addImm(0).add(predOps(ARMCC::AL));
break;
}
case G_MERGE_VALUES: {
if (!selectMergeValues(MIB, TII, MRI, TRI, RBI))
return false;
break;
}
case G_UNMERGE_VALUES: {
if (!selectUnmergeValues(MIB, TII, MRI, TRI, RBI))
return false;
break;
}
case G_BRCOND: {
if (!validReg(MRI, I.getOperand(0).getReg(), 1, ARM::GPRRegBankID)) {
LLVM_DEBUG(dbgs() << "Unsupported condition register for G_BRCOND");
return false;
}
// Set the flags.
auto Test =
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(Opcodes.TSTri))
.addReg(I.getOperand(0).getReg())
.addImm(1)
.add(predOps(ARMCC::AL));
if (!constrainSelectedInstRegOperands(*Test, TII, TRI, RBI))
return false;
// Branch conditionally.
auto Branch =
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(Opcodes.Bcc))
.add(I.getOperand(1))
.add(predOps(ARMCC::NE, ARM::CPSR));
if (!constrainSelectedInstRegOperands(*Branch, TII, TRI, RBI))
return false;
I.eraseFromParent();
return true;
}
case G_PHI: {
I.setDesc(TII.get(PHI));
Register DstReg = I.getOperand(0).getReg();
const TargetRegisterClass *RC = guessRegClass(DstReg, MRI, TRI, RBI);
if (!RBI.constrainGenericRegister(DstReg, *RC, MRI)) {
break;
}
return true;
}
default:
return false;
}
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
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