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swiftshader / SwiftShader / refs/heads/llvm10-clean / . / third_party / llvm-10.0 / llvm / lib / Target / AArch64 / AArch64InstructionSelector.cpp
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//===- AArch64InstructionSelector.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
/// AArch64.
/// \todo This should be generated by TableGen.
//===----------------------------------------------------------------------===//
#include "AArch64InstrInfo.h"
#include "AArch64MachineFunctionInfo.h"
#include "AArch64RegisterBankInfo.h"
#include "AArch64RegisterInfo.h"
#include "AArch64Subtarget.h"
#include "AArch64TargetMachine.h"
#include "MCTargetDesc/AArch64AddressingModes.h"
#include "llvm/ADT/Optional.h"
#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
#include "llvm/CodeGen/GlobalISel/InstructionSelectorImpl.h"
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
#include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
#include "llvm/CodeGen/GlobalISel/Utils.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/IntrinsicsAArch64.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#define DEBUG_TYPE "aarch64-isel"
using namespace llvm;
namespace {
#define GET_GLOBALISEL_PREDICATE_BITSET
#include "AArch64GenGlobalISel.inc"
#undef GET_GLOBALISEL_PREDICATE_BITSET
class AArch64InstructionSelector : public InstructionSelector {
public:
AArch64InstructionSelector(const AArch64TargetMachine &TM,
const AArch64Subtarget &STI,
const AArch64RegisterBankInfo &RBI);
bool select(MachineInstr &I) override;
static const char *getName() { return DEBUG_TYPE; }
void setupMF(MachineFunction &MF, GISelKnownBits &KB,
CodeGenCoverage &CoverageInfo) override {
InstructionSelector::setupMF(MF, KB, CoverageInfo);
// hasFnAttribute() is expensive to call on every BRCOND selection, so
// cache it here for each run of the selector.
ProduceNonFlagSettingCondBr =
!MF.getFunction().hasFnAttribute(Attribute::SpeculativeLoadHardening);
}
private:
/// tblgen-erated 'select' implementation, used as the initial selector for
/// the patterns that don't require complex C++.
bool selectImpl(MachineInstr &I, CodeGenCoverage &CoverageInfo) const;
// A lowering phase that runs before any selection attempts.
void preISelLower(MachineInstr &I) const;
// An early selection function that runs before the selectImpl() call.
bool earlySelect(MachineInstr &I) const;
bool earlySelectSHL(MachineInstr &I, MachineRegisterInfo &MRI) const;
/// Eliminate same-sized cross-bank copies into stores before selectImpl().
void contractCrossBankCopyIntoStore(MachineInstr &I,
MachineRegisterInfo &MRI) const;
bool selectVaStartAAPCS(MachineInstr &I, MachineFunction &MF,
MachineRegisterInfo &MRI) const;
bool selectVaStartDarwin(MachineInstr &I, MachineFunction &MF,
MachineRegisterInfo &MRI) const;
bool selectCompareBranch(MachineInstr &I, MachineFunction &MF,
MachineRegisterInfo &MRI) const;
bool selectVectorASHR(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectVectorSHL(MachineInstr &I, MachineRegisterInfo &MRI) const;
// Helper to generate an equivalent of scalar_to_vector into a new register,
// returned via 'Dst'.
MachineInstr *emitScalarToVector(unsigned EltSize,
const TargetRegisterClass *DstRC,
Register Scalar,
MachineIRBuilder &MIRBuilder) const;
/// Emit a lane insert into \p DstReg, or a new vector register if None is
/// provided.
///
/// The lane inserted into is defined by \p LaneIdx. The vector source
/// register is given by \p SrcReg. The register containing the element is
/// given by \p EltReg.
MachineInstr *emitLaneInsert(Optional<Register> DstReg, Register SrcReg,
Register EltReg, unsigned LaneIdx,
const RegisterBank &RB,
MachineIRBuilder &MIRBuilder) const;
bool selectInsertElt(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectBuildVector(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectMergeValues(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectUnmergeValues(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectShuffleVector(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectExtractElt(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectConcatVectors(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectSplitVectorUnmerge(MachineInstr &I,
MachineRegisterInfo &MRI) const;
bool selectIntrinsicWithSideEffects(MachineInstr &I,
MachineRegisterInfo &MRI) const;
bool selectIntrinsic(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectVectorICmp(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectIntrinsicTrunc(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectIntrinsicRound(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectJumpTable(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectBrJT(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectTLSGlobalValue(MachineInstr &I, MachineRegisterInfo &MRI) const;
unsigned emitConstantPoolEntry(Constant *CPVal, MachineFunction &MF) const;
MachineInstr *emitLoadFromConstantPool(Constant *CPVal,
MachineIRBuilder &MIRBuilder) const;
// Emit a vector concat operation.
MachineInstr *emitVectorConcat(Optional<Register> Dst, Register Op1,
Register Op2,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitIntegerCompare(MachineOperand &LHS, MachineOperand &RHS,
MachineOperand &Predicate,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitADD(Register DefReg, MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitCMN(MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitTST(const Register &LHS, const Register &RHS,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitExtractVectorElt(Optional<Register> DstReg,
const RegisterBank &DstRB, LLT ScalarTy,
Register VecReg, unsigned LaneIdx,
MachineIRBuilder &MIRBuilder) const;
/// Helper function for selecting G_FCONSTANT. If the G_FCONSTANT can be
/// materialized using a FMOV instruction, then update MI and return it.
/// Otherwise, do nothing and return a nullptr.
MachineInstr *emitFMovForFConstant(MachineInstr &MI,
MachineRegisterInfo &MRI) const;
/// Emit a CSet for a compare.
MachineInstr *emitCSetForICMP(Register DefReg, unsigned Pred,
MachineIRBuilder &MIRBuilder) const;
// Equivalent to the i32shift_a and friends from AArch64InstrInfo.td.
// We use these manually instead of using the importer since it doesn't
// support SDNodeXForm.
ComplexRendererFns selectShiftA_32(const MachineOperand &Root) const;
ComplexRendererFns selectShiftB_32(const MachineOperand &Root) const;
ComplexRendererFns selectShiftA_64(const MachineOperand &Root) const;
ComplexRendererFns selectShiftB_64(const MachineOperand &Root) const;
ComplexRendererFns select12BitValueWithLeftShift(uint64_t Immed) const;
ComplexRendererFns selectArithImmed(MachineOperand &Root) const;
ComplexRendererFns selectNegArithImmed(MachineOperand &Root) const;
ComplexRendererFns selectAddrModeUnscaled(MachineOperand &Root,
unsigned Size) const;
ComplexRendererFns selectAddrModeUnscaled8(MachineOperand &Root) const {
return selectAddrModeUnscaled(Root, 1);
}
ComplexRendererFns selectAddrModeUnscaled16(MachineOperand &Root) const {
return selectAddrModeUnscaled(Root, 2);
}
ComplexRendererFns selectAddrModeUnscaled32(MachineOperand &Root) const {
return selectAddrModeUnscaled(Root, 4);
}
ComplexRendererFns selectAddrModeUnscaled64(MachineOperand &Root) const {
return selectAddrModeUnscaled(Root, 8);
}
ComplexRendererFns selectAddrModeUnscaled128(MachineOperand &Root) const {
return selectAddrModeUnscaled(Root, 16);
}
ComplexRendererFns selectAddrModeIndexed(MachineOperand &Root,
unsigned Size) const;
template <int Width>
ComplexRendererFns selectAddrModeIndexed(MachineOperand &Root) const {
return selectAddrModeIndexed(Root, Width / 8);
}
bool isWorthFoldingIntoExtendedReg(MachineInstr &MI,
const MachineRegisterInfo &MRI) const;
ComplexRendererFns
selectAddrModeShiftedExtendXReg(MachineOperand &Root,
unsigned SizeInBytes) const;
/// Returns a \p ComplexRendererFns which contains a base, offset, and whether
/// or not a shift + extend should be folded into an addressing mode. Returns
/// None when this is not profitable or possible.
ComplexRendererFns
selectExtendedSHL(MachineOperand &Root, MachineOperand &Base,
MachineOperand &Offset, unsigned SizeInBytes,
bool WantsExt) const;
ComplexRendererFns selectAddrModeRegisterOffset(MachineOperand &Root) const;
ComplexRendererFns selectAddrModeXRO(MachineOperand &Root,
unsigned SizeInBytes) const;
template <int Width>
ComplexRendererFns selectAddrModeXRO(MachineOperand &Root) const {
return selectAddrModeXRO(Root, Width / 8);
}
ComplexRendererFns selectAddrModeWRO(MachineOperand &Root,
unsigned SizeInBytes) const;
template <int Width>
ComplexRendererFns selectAddrModeWRO(MachineOperand &Root) const {
return selectAddrModeWRO(Root, Width / 8);
}
ComplexRendererFns selectShiftedRegister(MachineOperand &Root) const;
ComplexRendererFns selectArithShiftedRegister(MachineOperand &Root) const {
return selectShiftedRegister(Root);
}
ComplexRendererFns selectLogicalShiftedRegister(MachineOperand &Root) const {
// TODO: selectShiftedRegister should allow for rotates on logical shifts.
// For now, make them the same. The only difference between the two is that
// logical shifts are allowed to fold in rotates. Otherwise, these are
// functionally the same.
return selectShiftedRegister(Root);
}
/// Given an extend instruction, determine the correct shift-extend type for
/// that instruction.
///
/// If the instruction is going to be used in a load or store, pass
/// \p IsLoadStore = true.
AArch64_AM::ShiftExtendType
getExtendTypeForInst(MachineInstr &MI, MachineRegisterInfo &MRI,
bool IsLoadStore = false) const;
/// Instructions that accept extend modifiers like UXTW expect the register
/// being extended to be a GPR32. Narrow ExtReg to a 32-bit register using a
/// subregister copy if necessary. Return either ExtReg, or the result of the
/// new copy.
Register narrowExtendRegIfNeeded(Register ExtReg,
MachineIRBuilder &MIB) const;
ComplexRendererFns selectArithExtendedRegister(MachineOperand &Root) const;
void renderTruncImm(MachineInstrBuilder &MIB, const MachineInstr &MI,
int OpIdx = -1) const;
void renderLogicalImm32(MachineInstrBuilder &MIB, const MachineInstr &I,
int OpIdx = -1) const;
void renderLogicalImm64(MachineInstrBuilder &MIB, const MachineInstr &I,
int OpIdx = -1) const;
// Materialize a GlobalValue or BlockAddress using a movz+movk sequence.
void materializeLargeCMVal(MachineInstr &I, const Value *V,
unsigned OpFlags) const;
// Optimization methods.
bool tryOptVectorShuffle(MachineInstr &I) const;
bool tryOptVectorDup(MachineInstr &MI) const;
bool tryOptSelect(MachineInstr &MI) const;
MachineInstr *tryFoldIntegerCompare(MachineOperand &LHS, MachineOperand &RHS,
MachineOperand &Predicate,
MachineIRBuilder &MIRBuilder) const;
/// Return true if \p MI is a load or store of \p NumBytes bytes.
bool isLoadStoreOfNumBytes(const MachineInstr &MI, unsigned NumBytes) const;
/// Returns true if \p MI is guaranteed to have the high-half of a 64-bit
/// register zeroed out. In other words, the result of MI has been explicitly
/// zero extended.
bool isDef32(const MachineInstr &MI) const;
const AArch64TargetMachine &TM;
const AArch64Subtarget &STI;
const AArch64InstrInfo &TII;
const AArch64RegisterInfo &TRI;
const AArch64RegisterBankInfo &RBI;
bool ProduceNonFlagSettingCondBr = false;
#define GET_GLOBALISEL_PREDICATES_DECL
#include "AArch64GenGlobalISel.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 "AArch64GenGlobalISel.inc"
#undef GET_GLOBALISEL_TEMPORARIES_DECL
};
} // end anonymous namespace
#define GET_GLOBALISEL_IMPL
#include "AArch64GenGlobalISel.inc"
#undef GET_GLOBALISEL_IMPL
AArch64InstructionSelector::AArch64InstructionSelector(
const AArch64TargetMachine &TM, const AArch64Subtarget &STI,
const AArch64RegisterBankInfo &RBI)
: InstructionSelector(), TM(TM), STI(STI), TII(*STI.getInstrInfo()),
TRI(*STI.getRegisterInfo()), RBI(RBI),
#define GET_GLOBALISEL_PREDICATES_INIT
#include "AArch64GenGlobalISel.inc"
#undef GET_GLOBALISEL_PREDICATES_INIT
#define GET_GLOBALISEL_TEMPORARIES_INIT
#include "AArch64GenGlobalISel.inc"
#undef GET_GLOBALISEL_TEMPORARIES_INIT
{
}
// FIXME: This should be target-independent, inferred from the types declared
// for each class in the bank.
static const TargetRegisterClass *
getRegClassForTypeOnBank(LLT Ty, const RegisterBank &RB,
const RegisterBankInfo &RBI,
bool GetAllRegSet = false) {
if (RB.getID() == AArch64::GPRRegBankID) {
if (Ty.getSizeInBits() <= 32)
return GetAllRegSet ? &AArch64::GPR32allRegClass
: &AArch64::GPR32RegClass;
if (Ty.getSizeInBits() == 64)
return GetAllRegSet ? &AArch64::GPR64allRegClass
: &AArch64::GPR64RegClass;
return nullptr;
}
if (RB.getID() == AArch64::FPRRegBankID) {
if (Ty.getSizeInBits() <= 16)
return &AArch64::FPR16RegClass;
if (Ty.getSizeInBits() == 32)
return &AArch64::FPR32RegClass;
if (Ty.getSizeInBits() == 64)
return &AArch64::FPR64RegClass;
if (Ty.getSizeInBits() == 128)
return &AArch64::FPR128RegClass;
return nullptr;
}
return nullptr;
}
/// Given a register bank, and size in bits, return the smallest register class
/// that can represent that combination.
static const TargetRegisterClass *
getMinClassForRegBank(const RegisterBank &RB, unsigned SizeInBits,
bool GetAllRegSet = false) {
unsigned RegBankID = RB.getID();
if (RegBankID == AArch64::GPRRegBankID) {
if (SizeInBits <= 32)
return GetAllRegSet ? &AArch64::GPR32allRegClass
: &AArch64::GPR32RegClass;
if (SizeInBits == 64)
return GetAllRegSet ? &AArch64::GPR64allRegClass
: &AArch64::GPR64RegClass;
}
if (RegBankID == AArch64::FPRRegBankID) {
switch (SizeInBits) {
default:
return nullptr;
case 8:
return &AArch64::FPR8RegClass;
case 16:
return &AArch64::FPR16RegClass;
case 32:
return &AArch64::FPR32RegClass;
case 64:
return &AArch64::FPR64RegClass;
case 128:
return &AArch64::FPR128RegClass;
}
}
return nullptr;
}
/// Returns the correct subregister to use for a given register class.
static bool getSubRegForClass(const TargetRegisterClass *RC,
const TargetRegisterInfo &TRI, unsigned &SubReg) {
switch (TRI.getRegSizeInBits(*RC)) {
case 8:
SubReg = AArch64::bsub;
break;
case 16:
SubReg = AArch64::hsub;
break;
case 32:
if (RC != &AArch64::FPR32RegClass)
SubReg = AArch64::sub_32;
else
SubReg = AArch64::ssub;
break;
case 64:
SubReg = AArch64::dsub;
break;
default:
LLVM_DEBUG(
dbgs() << "Couldn't find appropriate subregister for register class.");
return false;
}
return true;
}
/// Check whether \p I is a currently unsupported binary operation:
/// - it has an unsized type
/// - an operand is not a vreg
/// - all operands are not in the same bank
/// These are checks that should someday live in the verifier, but right now,
/// these are mostly limitations of the aarch64 selector.
static bool unsupportedBinOp(const MachineInstr &I,
const AArch64RegisterBankInfo &RBI,
const MachineRegisterInfo &MRI,
const AArch64RegisterInfo &TRI) {
LLT Ty = MRI.getType(I.getOperand(0).getReg());
if (!Ty.isValid()) {
LLVM_DEBUG(dbgs() << "Generic binop register should be typed\n");
return true;
}
const RegisterBank *PrevOpBank = nullptr;
for (auto &MO : I.operands()) {
// FIXME: Support non-register operands.
if (!MO.isReg()) {
LLVM_DEBUG(dbgs() << "Generic inst non-reg operands are unsupported\n");
return true;
}
// FIXME: Can generic operations have physical registers operands? If
// so, this will need to be taught about that, and we'll need to get the
// bank out of the minimal class for the register.
// Either way, this needs to be documented (and possibly verified).
if (!Register::isVirtualRegister(MO.getReg())) {
LLVM_DEBUG(dbgs() << "Generic inst has physical register operand\n");
return true;
}
const RegisterBank *OpBank = RBI.getRegBank(MO.getReg(), MRI, TRI);
if (!OpBank) {
LLVM_DEBUG(dbgs() << "Generic register has no bank or class\n");
return true;
}
if (PrevOpBank && OpBank != PrevOpBank) {
LLVM_DEBUG(dbgs() << "Generic inst operands have different banks\n");
return true;
}
PrevOpBank = OpBank;
}
return false;
}
/// Select the AArch64 opcode for the basic binary operation \p GenericOpc
/// (such as G_OR or G_SDIV), appropriate for the register bank \p RegBankID
/// and of size \p OpSize.
/// \returns \p GenericOpc if the combination is unsupported.
static unsigned selectBinaryOp(unsigned GenericOpc, unsigned RegBankID,
unsigned OpSize) {
switch (RegBankID) {
case AArch64::GPRRegBankID:
if (OpSize == 32) {
switch (GenericOpc) {
case TargetOpcode::G_SHL:
return AArch64::LSLVWr;
case TargetOpcode::G_LSHR:
return AArch64::LSRVWr;
case TargetOpcode::G_ASHR:
return AArch64::ASRVWr;
default:
return GenericOpc;
}
} else if (OpSize == 64) {
switch (GenericOpc) {
case TargetOpcode::G_PTR_ADD:
return AArch64::ADDXrr;
case TargetOpcode::G_SHL:
return AArch64::LSLVXr;
case TargetOpcode::G_LSHR:
return AArch64::LSRVXr;
case TargetOpcode::G_ASHR:
return AArch64::ASRVXr;
default:
return GenericOpc;
}
}
break;
case AArch64::FPRRegBankID:
switch (OpSize) {
case 32:
switch (GenericOpc) {
case TargetOpcode::G_FADD:
return AArch64::FADDSrr;
case TargetOpcode::G_FSUB:
return AArch64::FSUBSrr;
case TargetOpcode::G_FMUL:
return AArch64::FMULSrr;
case TargetOpcode::G_FDIV:
return AArch64::FDIVSrr;
default:
return GenericOpc;
}
case 64:
switch (GenericOpc) {
case TargetOpcode::G_FADD:
return AArch64::FADDDrr;
case TargetOpcode::G_FSUB:
return AArch64::FSUBDrr;
case TargetOpcode::G_FMUL:
return AArch64::FMULDrr;
case TargetOpcode::G_FDIV:
return AArch64::FDIVDrr;
case TargetOpcode::G_OR:
return AArch64::ORRv8i8;
default:
return GenericOpc;
}
}
break;
}
return GenericOpc;
}
/// Select the AArch64 opcode for the G_LOAD or G_STORE operation \p GenericOpc,
/// appropriate for the (value) register bank \p RegBankID and of memory access
/// size \p OpSize. This returns the variant with the base+unsigned-immediate
/// addressing mode (e.g., LDRXui).
/// \returns \p GenericOpc if the combination is unsupported.
static unsigned selectLoadStoreUIOp(unsigned GenericOpc, unsigned RegBankID,
unsigned OpSize) {
const bool isStore = GenericOpc == TargetOpcode::G_STORE;
switch (RegBankID) {
case AArch64::GPRRegBankID:
switch (OpSize) {
case 8:
return isStore ? AArch64::STRBBui : AArch64::LDRBBui;
case 16:
return isStore ? AArch64::STRHHui : AArch64::LDRHHui;
case 32:
return isStore ? AArch64::STRWui : AArch64::LDRWui;
case 64:
return isStore ? AArch64::STRXui : AArch64::LDRXui;
}
break;
case AArch64::FPRRegBankID:
switch (OpSize) {
case 8:
return isStore ? AArch64::STRBui : AArch64::LDRBui;
case 16:
return isStore ? AArch64::STRHui : AArch64::LDRHui;
case 32:
return isStore ? AArch64::STRSui : AArch64::LDRSui;
case 64:
return isStore ? AArch64::STRDui : AArch64::LDRDui;
}
break;
}
return GenericOpc;
}
#ifndef NDEBUG
/// Helper function that verifies that we have a valid copy at the end of
/// selectCopy. Verifies that the source and dest have the expected sizes and
/// then returns true.
static bool isValidCopy(const MachineInstr &I, const RegisterBank &DstBank,
const MachineRegisterInfo &MRI,
const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) {
const Register DstReg = I.getOperand(0).getReg();
const Register SrcReg = I.getOperand(1).getReg();
const unsigned DstSize = RBI.getSizeInBits(DstReg, MRI, TRI);
const unsigned SrcSize = RBI.getSizeInBits(SrcReg, MRI, TRI);
// Make sure the size of the source and dest line up.
assert(
(DstSize == SrcSize ||
// Copies are a mean to setup initial types, the number of
// bits may not exactly match.
(Register::isPhysicalRegister(SrcReg) && DstSize <= SrcSize) ||
// Copies are a mean to copy bits around, as long as we are
// on the same register class, that's fine. Otherwise, that
// means we need some SUBREG_TO_REG or AND & co.
(((DstSize + 31) / 32 == (SrcSize + 31) / 32) && DstSize > SrcSize)) &&
"Copy with different width?!");
// Check the size of the destination.
assert((DstSize <= 64 || DstBank.getID() == AArch64::FPRRegBankID) &&
"GPRs cannot get more than 64-bit width values");
return true;
}
#endif
/// Helper function for selectCopy. Inserts a subregister copy from
/// \p *From to \p *To, linking it up to \p I.
///
/// e.g, given I = "Dst = COPY SrcReg", we'll transform that into
///
/// CopyReg (From class) = COPY SrcReg
/// SubRegCopy (To class) = COPY CopyReg:SubReg
/// Dst = COPY SubRegCopy
static bool selectSubregisterCopy(MachineInstr &I, MachineRegisterInfo &MRI,
const RegisterBankInfo &RBI, Register SrcReg,
const TargetRegisterClass *From,
const TargetRegisterClass *To,
unsigned SubReg) {
MachineIRBuilder MIB(I);
auto Copy = MIB.buildCopy({From}, {SrcReg});
auto SubRegCopy = MIB.buildInstr(TargetOpcode::COPY, {To}, {})
.addReg(Copy.getReg(0), 0, SubReg);
MachineOperand &RegOp = I.getOperand(1);
RegOp.setReg(SubRegCopy.getReg(0));
// It's possible that the destination register won't be constrained. Make
// sure that happens.
if (!Register::isPhysicalRegister(I.getOperand(0).getReg()))
RBI.constrainGenericRegister(I.getOperand(0).getReg(), *To, MRI);
return true;
}
/// Helper function to get the source and destination register classes for a
/// copy. Returns a std::pair containing the source register class for the
/// copy, and the destination register class for the copy. If a register class
/// cannot be determined, then it will be nullptr.
static std::pair<const TargetRegisterClass *, const TargetRegisterClass *>
getRegClassesForCopy(MachineInstr &I, const TargetInstrInfo &TII,
MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) {
Register DstReg = I.getOperand(0).getReg();
Register SrcReg = I.getOperand(1).getReg();
const RegisterBank &DstRegBank = *RBI.getRegBank(DstReg, MRI, TRI);
const RegisterBank &SrcRegBank = *RBI.getRegBank(SrcReg, MRI, TRI);
unsigned DstSize = RBI.getSizeInBits(DstReg, MRI, TRI);
unsigned SrcSize = RBI.getSizeInBits(SrcReg, MRI, TRI);
// Special casing for cross-bank copies of s1s. We can technically represent
// a 1-bit value with any size of register. The minimum size for a GPR is 32
// bits. So, we need to put the FPR on 32 bits as well.
//
// FIXME: I'm not sure if this case holds true outside of copies. If it does,
// then we can pull it into the helpers that get the appropriate class for a
// register bank. Or make a new helper that carries along some constraint
// information.
if (SrcRegBank != DstRegBank && (DstSize == 1 && SrcSize == 1))
SrcSize = DstSize = 32;
return {getMinClassForRegBank(SrcRegBank, SrcSize, true),
getMinClassForRegBank(DstRegBank, DstSize, true)};
}
static bool selectCopy(MachineInstr &I, const TargetInstrInfo &TII,
MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) {
Register DstReg = I.getOperand(0).getReg();
Register SrcReg = I.getOperand(1).getReg();
const RegisterBank &DstRegBank = *RBI.getRegBank(DstReg, MRI, TRI);
const RegisterBank &SrcRegBank = *RBI.getRegBank(SrcReg, MRI, TRI);
// Find the correct register classes for the source and destination registers.
const TargetRegisterClass *SrcRC;
const TargetRegisterClass *DstRC;
std::tie(SrcRC, DstRC) = getRegClassesForCopy(I, TII, MRI, TRI, RBI);
if (!DstRC) {
LLVM_DEBUG(dbgs() << "Unexpected dest size "
<< RBI.getSizeInBits(DstReg, MRI, TRI) << '\n');
return false;
}
// A couple helpers below, for making sure that the copy we produce is valid.
// Set to true if we insert a SUBREG_TO_REG. If we do this, then we don't want
// to verify that the src and dst are the same size, since that's handled by
// the SUBREG_TO_REG.
bool KnownValid = false;
// Returns true, or asserts if something we don't expect happens. Instead of
// returning true, we return isValidCopy() to ensure that we verify the
// result.
auto CheckCopy = [&]() {
// If we have a bitcast or something, we can't have physical registers.
assert((I.isCopy() ||
(!Register::isPhysicalRegister(I.getOperand(0).getReg()) &&
!Register::isPhysicalRegister(I.getOperand(1).getReg()))) &&
"No phys reg on generic operator!");
assert(KnownValid || isValidCopy(I, DstRegBank, MRI, TRI, RBI));
(void)KnownValid;
return true;
};
// Is this a copy? If so, then we may need to insert a subregister copy, or
// a SUBREG_TO_REG.
if (I.isCopy()) {
// Yes. Check if there's anything to fix up.
if (!SrcRC) {
LLVM_DEBUG(dbgs() << "Couldn't determine source register class\n");
return false;
}
unsigned SrcSize = TRI.getRegSizeInBits(*SrcRC);
unsigned DstSize = TRI.getRegSizeInBits(*DstRC);
// If we're doing a cross-bank copy on different-sized registers, we need
// to do a bit more work.
if (SrcSize > DstSize) {
// We're doing a cross-bank copy into a smaller register. We need a
// subregister copy. First, get a register class that's on the same bank
// as the destination, but the same size as the source.
const TargetRegisterClass *SubregRC =
getMinClassForRegBank(DstRegBank, SrcSize, true);
assert(SubregRC && "Didn't get a register class for subreg?");
// Get the appropriate subregister for the destination.
unsigned SubReg = 0;
if (!getSubRegForClass(DstRC, TRI, SubReg)) {
LLVM_DEBUG(dbgs() << "Couldn't determine subregister for copy.\n");
return false;
}
// Now, insert a subregister copy using the new register class.
selectSubregisterCopy(I, MRI, RBI, SrcReg, SubregRC, DstRC, SubReg);
return CheckCopy();
}
// Is this a cross-bank copy?
if (DstRegBank.getID() != SrcRegBank.getID()) {
if (DstRegBank.getID() == AArch64::GPRRegBankID && DstSize == 32 &&
SrcSize == 16) {
// Special case for FPR16 to GPR32.
// FIXME: This can probably be generalized like the above case.
Register PromoteReg =
MRI.createVirtualRegister(&AArch64::FPR32RegClass);
BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(AArch64::SUBREG_TO_REG), PromoteReg)
.addImm(0)
.addUse(SrcReg)
.addImm(AArch64::hsub);
MachineOperand &RegOp = I.getOperand(1);
RegOp.setReg(PromoteReg);
// Promise that the copy is implicitly validated by the SUBREG_TO_REG.
KnownValid = true;
}
}
// If the destination is a physical register, then there's nothing to
// change, so we're done.
if (Register::isPhysicalRegister(DstReg))
return CheckCopy();
}
// No need to constrain SrcReg. It will get constrained when we hit another
// of its use or its defs. Copies do not have constraints.
if (!RBI.constrainGenericRegister(DstReg, *DstRC, MRI)) {
LLVM_DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())
<< " operand\n");
return false;
}
I.setDesc(TII.get(AArch64::COPY));
return CheckCopy();
}
static unsigned selectFPConvOpc(unsigned GenericOpc, LLT DstTy, LLT SrcTy) {
if (!DstTy.isScalar() || !SrcTy.isScalar())
return GenericOpc;
const unsigned DstSize = DstTy.getSizeInBits();
const unsigned SrcSize = SrcTy.getSizeInBits();
switch (DstSize) {
case 32:
switch (SrcSize) {
case 32:
switch (GenericOpc) {
case TargetOpcode::G_SITOFP:
return AArch64::SCVTFUWSri;
case TargetOpcode::G_UITOFP:
return AArch64::UCVTFUWSri;
case TargetOpcode::G_FPTOSI:
return AArch64::FCVTZSUWSr;
case TargetOpcode::G_FPTOUI:
return AArch64::FCVTZUUWSr;
default:
return GenericOpc;
}
case 64:
switch (GenericOpc) {
case TargetOpcode::G_SITOFP:
return AArch64::SCVTFUXSri;
case TargetOpcode::G_UITOFP:
return AArch64::UCVTFUXSri;
case TargetOpcode::G_FPTOSI:
return AArch64::FCVTZSUWDr;
case TargetOpcode::G_FPTOUI:
return AArch64::FCVTZUUWDr;
default:
return GenericOpc;
}
default:
return GenericOpc;
}
case 64:
switch (SrcSize) {
case 32:
switch (GenericOpc) {
case TargetOpcode::G_SITOFP:
return AArch64::SCVTFUWDri;
case TargetOpcode::G_UITOFP:
return AArch64::UCVTFUWDri;
case TargetOpcode::G_FPTOSI:
return AArch64::FCVTZSUXSr;
case TargetOpcode::G_FPTOUI:
return AArch64::FCVTZUUXSr;
default:
return GenericOpc;
}
case 64:
switch (GenericOpc) {
case TargetOpcode::G_SITOFP:
return AArch64::SCVTFUXDri;
case TargetOpcode::G_UITOFP:
return AArch64::UCVTFUXDri;
case TargetOpcode::G_FPTOSI:
return AArch64::FCVTZSUXDr;
case TargetOpcode::G_FPTOUI:
return AArch64::FCVTZUUXDr;
default:
return GenericOpc;
}
default:
return GenericOpc;
}
default:
return GenericOpc;
};
return GenericOpc;
}
static unsigned selectSelectOpc(MachineInstr &I, MachineRegisterInfo &MRI,
const RegisterBankInfo &RBI) {
const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
bool IsFP = (RBI.getRegBank(I.getOperand(0).getReg(), MRI, TRI)->getID() !=
AArch64::GPRRegBankID);
LLT Ty = MRI.getType(I.getOperand(0).getReg());
if (Ty == LLT::scalar(32))
return IsFP ? AArch64::FCSELSrrr : AArch64::CSELWr;
else if (Ty == LLT::scalar(64) || Ty == LLT::pointer(0, 64))
return IsFP ? AArch64::FCSELDrrr : AArch64::CSELXr;
return 0;
}
/// Helper function to select the opcode for a G_FCMP.
static unsigned selectFCMPOpc(MachineInstr &I, MachineRegisterInfo &MRI) {
// If this is a compare against +0.0, then we don't have to explicitly
// materialize a constant.
const ConstantFP *FPImm = getConstantFPVRegVal(I.getOperand(3).getReg(), MRI);
bool ShouldUseImm = FPImm && (FPImm->isZero() && !FPImm->isNegative());
unsigned OpSize = MRI.getType(I.getOperand(2).getReg()).getSizeInBits();
if (OpSize != 32 && OpSize != 64)
return 0;
unsigned CmpOpcTbl[2][2] = {{AArch64::FCMPSrr, AArch64::FCMPDrr},
{AArch64::FCMPSri, AArch64::FCMPDri}};
return CmpOpcTbl[ShouldUseImm][OpSize == 64];
}
/// Returns true if \p P is an unsigned integer comparison predicate.
static bool isUnsignedICMPPred(const CmpInst::Predicate P) {
switch (P) {
default:
return false;
case CmpInst::ICMP_UGT:
case CmpInst::ICMP_UGE:
case CmpInst::ICMP_ULT:
case CmpInst::ICMP_ULE:
return true;
}
}
static AArch64CC::CondCode changeICMPPredToAArch64CC(CmpInst::Predicate P) {
switch (P) {
default:
llvm_unreachable("Unknown condition code!");
case CmpInst::ICMP_NE:
return AArch64CC::NE;
case CmpInst::ICMP_EQ:
return AArch64CC::EQ;
case CmpInst::ICMP_SGT:
return AArch64CC::GT;
case CmpInst::ICMP_SGE:
return AArch64CC::GE;
case CmpInst::ICMP_SLT:
return AArch64CC::LT;
case CmpInst::ICMP_SLE:
return AArch64CC::LE;
case CmpInst::ICMP_UGT:
return AArch64CC::HI;
case CmpInst::ICMP_UGE:
return AArch64CC::HS;
case CmpInst::ICMP_ULT:
return AArch64CC::LO;
case CmpInst::ICMP_ULE:
return AArch64CC::LS;
}
}
static void changeFCMPPredToAArch64CC(CmpInst::Predicate P,
AArch64CC::CondCode &CondCode,
AArch64CC::CondCode &CondCode2) {
CondCode2 = AArch64CC::AL;
switch (P) {
default:
llvm_unreachable("Unknown FP condition!");
case CmpInst::FCMP_OEQ:
CondCode = AArch64CC::EQ;
break;
case CmpInst::FCMP_OGT:
CondCode = AArch64CC::GT;
break;
case CmpInst::FCMP_OGE:
CondCode = AArch64CC::GE;
break;
case CmpInst::FCMP_OLT:
CondCode = AArch64CC::MI;
break;
case CmpInst::FCMP_OLE:
CondCode = AArch64CC::LS;
break;
case CmpInst::FCMP_ONE:
CondCode = AArch64CC::MI;
CondCode2 = AArch64CC::GT;
break;
case CmpInst::FCMP_ORD:
CondCode = AArch64CC::VC;
break;
case CmpInst::FCMP_UNO:
CondCode = AArch64CC::VS;
break;
case CmpInst::FCMP_UEQ:
CondCode = AArch64CC::EQ;
CondCode2 = AArch64CC::VS;
break;
case CmpInst::FCMP_UGT:
CondCode = AArch64CC::HI;
break;
case CmpInst::FCMP_UGE:
CondCode = AArch64CC::PL;
break;
case CmpInst::FCMP_ULT:
CondCode = AArch64CC::LT;
break;
case CmpInst::FCMP_ULE:
CondCode = AArch64CC::LE;
break;
case CmpInst::FCMP_UNE:
CondCode = AArch64CC::NE;
break;
}
}
bool AArch64InstructionSelector::selectCompareBranch(
MachineInstr &I, MachineFunction &MF, MachineRegisterInfo &MRI) const {
const Register CondReg = I.getOperand(0).getReg();
MachineBasicBlock *DestMBB = I.getOperand(1).getMBB();
MachineInstr *CCMI = MRI.getVRegDef(CondReg);
if (CCMI->getOpcode() == TargetOpcode::G_TRUNC)
CCMI = MRI.getVRegDef(CCMI->getOperand(1).getReg());
if (CCMI->getOpcode() != TargetOpcode::G_ICMP)
return false;
Register LHS = CCMI->getOperand(2).getReg();
Register RHS = CCMI->getOperand(3).getReg();
auto VRegAndVal = getConstantVRegValWithLookThrough(RHS, MRI);
if (!VRegAndVal)
std::swap(RHS, LHS);
VRegAndVal = getConstantVRegValWithLookThrough(RHS, MRI);
if (!VRegAndVal || VRegAndVal->Value != 0) {
MachineIRBuilder MIB(I);
// If we can't select a CBZ then emit a cmp + Bcc.
if (!emitIntegerCompare(CCMI->getOperand(2), CCMI->getOperand(3),
CCMI->getOperand(1), MIB))
return false;
const AArch64CC::CondCode CC = changeICMPPredToAArch64CC(
(CmpInst::Predicate)CCMI->getOperand(1).getPredicate());
MIB.buildInstr(AArch64::Bcc, {}, {}).addImm(CC).addMBB(DestMBB);
I.eraseFromParent();
return true;
}
const RegisterBank &RB = *RBI.getRegBank(LHS, MRI, TRI);
if (RB.getID() != AArch64::GPRRegBankID)
return false;
const auto Pred = (CmpInst::Predicate)CCMI->getOperand(1).getPredicate();
if (Pred != CmpInst::ICMP_NE && Pred != CmpInst::ICMP_EQ)
return false;
const unsigned CmpWidth = MRI.getType(LHS).getSizeInBits();
unsigned CBOpc = 0;
if (CmpWidth <= 32)
CBOpc = (Pred == CmpInst::ICMP_EQ ? AArch64::CBZW : AArch64::CBNZW);
else if (CmpWidth == 64)
CBOpc = (Pred == CmpInst::ICMP_EQ ? AArch64::CBZX : AArch64::CBNZX);
else
return false;
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(CBOpc))
.addUse(LHS)
.addMBB(DestMBB)
.constrainAllUses(TII, TRI, RBI);
I.eraseFromParent();
return true;
}
/// Returns the element immediate value of a vector shift operand if found.
/// This needs to detect a splat-like operation, e.g. a G_BUILD_VECTOR.
static Optional<int64_t> getVectorShiftImm(Register Reg,
MachineRegisterInfo &MRI) {
assert(MRI.getType(Reg).isVector() && "Expected a *vector* shift operand");
MachineInstr *OpMI = MRI.getVRegDef(Reg);
assert(OpMI && "Expected to find a vreg def for vector shift operand");
if (OpMI->getOpcode() != TargetOpcode::G_BUILD_VECTOR)
return None;
// Check all operands are identical immediates.
int64_t ImmVal = 0;
for (unsigned Idx = 1; Idx < OpMI->getNumOperands(); ++Idx) {
auto VRegAndVal = getConstantVRegValWithLookThrough(OpMI->getOperand(Idx).getReg(), MRI);
if (!VRegAndVal)
return None;
if (Idx == 1)
ImmVal = VRegAndVal->Value;
if (ImmVal != VRegAndVal->Value)
return None;
}
return ImmVal;
}
/// Matches and returns the shift immediate value for a SHL instruction given
/// a shift operand.
static Optional<int64_t> getVectorSHLImm(LLT SrcTy, Register Reg, MachineRegisterInfo &MRI) {
Optional<int64_t> ShiftImm = getVectorShiftImm(Reg, MRI);
if (!ShiftImm)
return None;
// Check the immediate is in range for a SHL.
int64_t Imm = *ShiftImm;
if (Imm < 0)
return None;
switch (SrcTy.getElementType().getSizeInBits()) {
default:
LLVM_DEBUG(dbgs() << "Unhandled element type for vector shift");
return None;
case 8:
if (Imm > 7)
return None;
break;
case 16:
if (Imm > 15)
return None;
break;
case 32:
if (Imm > 31)
return None;
break;
case 64:
if (Imm > 63)
return None;
break;
}
return Imm;
}
bool AArch64InstructionSelector::selectVectorSHL(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_SHL);
Register DstReg = I.getOperand(0).getReg();
const LLT Ty = MRI.getType(DstReg);
Register Src1Reg = I.getOperand(1).getReg();
Register Src2Reg = I.getOperand(2).getReg();
if (!Ty.isVector())
return false;
// Check if we have a vector of constants on RHS that we can select as the
// immediate form.
Optional<int64_t> ImmVal = getVectorSHLImm(Ty, Src2Reg, MRI);
unsigned Opc = 0;
if (Ty == LLT::vector(2, 64)) {
Opc = ImmVal ? AArch64::SHLv2i64_shift : AArch64::USHLv2i64;
} else if (Ty == LLT::vector(4, 32)) {
Opc = ImmVal ? AArch64::SHLv4i32_shift : AArch64::USHLv4i32;
} else if (Ty == LLT::vector(2, 32)) {
Opc = ImmVal ? AArch64::SHLv2i32_shift : AArch64::USHLv2i32;
} else {
LLVM_DEBUG(dbgs() << "Unhandled G_SHL type");
return false;
}
MachineIRBuilder MIB(I);
auto Shl = MIB.buildInstr(Opc, {DstReg}, {Src1Reg});
if (ImmVal)
Shl.addImm(*ImmVal);
else
Shl.addUse(Src2Reg);
constrainSelectedInstRegOperands(*Shl, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectVectorASHR(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_ASHR);
Register DstReg = I.getOperand(0).getReg();
const LLT Ty = MRI.getType(DstReg);
Register Src1Reg = I.getOperand(1).getReg();
Register Src2Reg = I.getOperand(2).getReg();
if (!Ty.isVector())
return false;
// There is not a shift right register instruction, but the shift left
// register instruction takes a signed value, where negative numbers specify a
// right shift.
unsigned Opc = 0;
unsigned NegOpc = 0;
const TargetRegisterClass *RC = nullptr;
if (Ty == LLT::vector(2, 64)) {
Opc = AArch64::SSHLv2i64;
NegOpc = AArch64::NEGv2i64;
RC = &AArch64::FPR128RegClass;
} else if (Ty == LLT::vector(4, 32)) {
Opc = AArch64::SSHLv4i32;
NegOpc = AArch64::NEGv4i32;
RC = &AArch64::FPR128RegClass;
} else if (Ty == LLT::vector(2, 32)) {
Opc = AArch64::SSHLv2i32;
NegOpc = AArch64::NEGv2i32;
RC = &AArch64::FPR64RegClass;
} else {
LLVM_DEBUG(dbgs() << "Unhandled G_ASHR type");
return false;
}
MachineIRBuilder MIB(I);
auto Neg = MIB.buildInstr(NegOpc, {RC}, {Src2Reg});
constrainSelectedInstRegOperands(*Neg, TII, TRI, RBI);
auto SShl = MIB.buildInstr(Opc, {DstReg}, {Src1Reg, Neg});
constrainSelectedInstRegOperands(*SShl, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectVaStartAAPCS(
MachineInstr &I, MachineFunction &MF, MachineRegisterInfo &MRI) const {
return false;
}
bool AArch64InstructionSelector::selectVaStartDarwin(
MachineInstr &I, MachineFunction &MF, MachineRegisterInfo &MRI) const {
AArch64FunctionInfo *FuncInfo = MF.getInfo<AArch64FunctionInfo>();
Register ListReg = I.getOperand(0).getReg();
Register ArgsAddrReg = MRI.createVirtualRegister(&AArch64::GPR64RegClass);
auto MIB =
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(AArch64::ADDXri))
.addDef(ArgsAddrReg)
.addFrameIndex(FuncInfo->getVarArgsStackIndex())
.addImm(0)
.addImm(0);
constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);
MIB = BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(AArch64::STRXui))
.addUse(ArgsAddrReg)
.addUse(ListReg)
.addImm(0)
.addMemOperand(*I.memoperands_begin());
constrainSelectedInstRegOperands(*MIB, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
void AArch64InstructionSelector::materializeLargeCMVal(
MachineInstr &I, const Value *V, unsigned OpFlags) const {
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
MachineIRBuilder MIB(I);
auto MovZ = MIB.buildInstr(AArch64::MOVZXi, {&AArch64::GPR64RegClass}, {});
MovZ->addOperand(MF, I.getOperand(1));
MovZ->getOperand(1).setTargetFlags(OpFlags | AArch64II::MO_G0 |
AArch64II::MO_NC);
MovZ->addOperand(MF, MachineOperand::CreateImm(0));
constrainSelectedInstRegOperands(*MovZ, TII, TRI, RBI);
auto BuildMovK = [&](Register SrcReg, unsigned char Flags, unsigned Offset,
Register ForceDstReg) {
Register DstReg = ForceDstReg
? ForceDstReg
: MRI.createVirtualRegister(&AArch64::GPR64RegClass);
auto MovI = MIB.buildInstr(AArch64::MOVKXi).addDef(DstReg).addUse(SrcReg);
if (auto *GV = dyn_cast<GlobalValue>(V)) {
MovI->addOperand(MF, MachineOperand::CreateGA(
GV, MovZ->getOperand(1).getOffset(), Flags));
} else {
MovI->addOperand(
MF, MachineOperand::CreateBA(cast<BlockAddress>(V),
MovZ->getOperand(1).getOffset(), Flags));
}
MovI->addOperand(MF, MachineOperand::CreateImm(Offset));
constrainSelectedInstRegOperands(*MovI, TII, TRI, RBI);
return DstReg;
};
Register DstReg = BuildMovK(MovZ.getReg(0),
AArch64II::MO_G1 | AArch64II::MO_NC, 16, 0);
DstReg = BuildMovK(DstReg, AArch64II::MO_G2 | AArch64II::MO_NC, 32, 0);
BuildMovK(DstReg, AArch64II::MO_G3, 48, I.getOperand(0).getReg());
return;
}
void AArch64InstructionSelector::preISelLower(MachineInstr &I) const {
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
switch (I.getOpcode()) {
case TargetOpcode::G_SHL:
case TargetOpcode::G_ASHR:
case TargetOpcode::G_LSHR: {
// These shifts are legalized to have 64 bit shift amounts because we want
// to take advantage of the existing imported selection patterns that assume
// the immediates are s64s. However, if the shifted type is 32 bits and for
// some reason we receive input GMIR that has an s64 shift amount that's not
// a G_CONSTANT, insert a truncate so that we can still select the s32
// register-register variant.
Register SrcReg = I.getOperand(1).getReg();
Register ShiftReg = I.getOperand(2).getReg();
const LLT ShiftTy = MRI.getType(ShiftReg);
const LLT SrcTy = MRI.getType(SrcReg);
if (SrcTy.isVector())
return;
assert(!ShiftTy.isVector() && "unexpected vector shift ty");
if (SrcTy.getSizeInBits() != 32 || ShiftTy.getSizeInBits() != 64)
return;
auto *AmtMI = MRI.getVRegDef(ShiftReg);
assert(AmtMI && "could not find a vreg definition for shift amount");
if (AmtMI->getOpcode() != TargetOpcode::G_CONSTANT) {
// Insert a subregister copy to implement a 64->32 trunc
MachineIRBuilder MIB(I);
auto Trunc = MIB.buildInstr(TargetOpcode::COPY, {SrcTy}, {})
.addReg(ShiftReg, 0, AArch64::sub_32);
MRI.setRegBank(Trunc.getReg(0), RBI.getRegBank(AArch64::GPRRegBankID));
I.getOperand(2).setReg(Trunc.getReg(0));
}
return;
}
case TargetOpcode::G_STORE:
contractCrossBankCopyIntoStore(I, MRI);
return;
default:
return;
}
}
bool AArch64InstructionSelector::earlySelectSHL(
MachineInstr &I, MachineRegisterInfo &MRI) const {
// We try to match the immediate variant of LSL, which is actually an alias
// for a special case of UBFM. Otherwise, we fall back to the imported
// selector which will match the register variant.
assert(I.getOpcode() == TargetOpcode::G_SHL && "unexpected op");
const auto &MO = I.getOperand(2);
auto VRegAndVal = getConstantVRegVal(MO.getReg(), MRI);
if (!VRegAndVal)
return false;
const LLT DstTy = MRI.getType(I.getOperand(0).getReg());
if (DstTy.isVector())
return false;
bool Is64Bit = DstTy.getSizeInBits() == 64;
auto Imm1Fn = Is64Bit ? selectShiftA_64(MO) : selectShiftA_32(MO);
auto Imm2Fn = Is64Bit ? selectShiftB_64(MO) : selectShiftB_32(MO);
MachineIRBuilder MIB(I);
if (!Imm1Fn || !Imm2Fn)
return false;
auto NewI =
MIB.buildInstr(Is64Bit ? AArch64::UBFMXri : AArch64::UBFMWri,
{I.getOperand(0).getReg()}, {I.getOperand(1).getReg()});
for (auto &RenderFn : *Imm1Fn)
RenderFn(NewI);
for (auto &RenderFn : *Imm2Fn)
RenderFn(NewI);
I.eraseFromParent();
return constrainSelectedInstRegOperands(*NewI, TII, TRI, RBI);
}
void AArch64InstructionSelector::contractCrossBankCopyIntoStore(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_STORE && "Expected G_STORE");
// If we're storing a scalar, it doesn't matter what register bank that
// scalar is on. All that matters is the size.
//
// So, if we see something like this (with a 32-bit scalar as an example):
//
// %x:gpr(s32) = ... something ...
// %y:fpr(s32) = COPY %x:gpr(s32)
// G_STORE %y:fpr(s32)
//
// We can fix this up into something like this:
//
// G_STORE %x:gpr(s32)
//
// And then continue the selection process normally.
MachineInstr *Def = getDefIgnoringCopies(I.getOperand(0).getReg(), MRI);
if (!Def)
return;
Register DefDstReg = Def->getOperand(0).getReg();
LLT DefDstTy = MRI.getType(DefDstReg);
Register StoreSrcReg = I.getOperand(0).getReg();
LLT StoreSrcTy = MRI.getType(StoreSrcReg);
// If we get something strange like a physical register, then we shouldn't
// go any further.
if (!DefDstTy.isValid())
return;
// Are the source and dst types the same size?
if (DefDstTy.getSizeInBits() != StoreSrcTy.getSizeInBits())
return;
if (RBI.getRegBank(StoreSrcReg, MRI, TRI) ==
RBI.getRegBank(DefDstReg, MRI, TRI))
return;
// We have a cross-bank copy, which is entering a store. Let's fold it.
I.getOperand(0).setReg(DefDstReg);
}
bool AArch64InstructionSelector::earlySelect(MachineInstr &I) const {
assert(I.getParent() && "Instruction should be in a basic block!");
assert(I.getParent()->getParent() && "Instruction should be in a function!");
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
switch (I.getOpcode()) {
case TargetOpcode::G_SHL:
return earlySelectSHL(I, MRI);
case TargetOpcode::G_CONSTANT: {
bool IsZero = false;
if (I.getOperand(1).isCImm())
IsZero = I.getOperand(1).getCImm()->getZExtValue() == 0;
else if (I.getOperand(1).isImm())
IsZero = I.getOperand(1).getImm() == 0;
if (!IsZero)
return false;
Register DefReg = I.getOperand(0).getReg();
LLT Ty = MRI.getType(DefReg);
if (Ty != LLT::scalar(64) && Ty != LLT::scalar(32))
return false;
if (Ty == LLT::scalar(64)) {
I.getOperand(1).ChangeToRegister(AArch64::XZR, false);
RBI.constrainGenericRegister(DefReg, AArch64::GPR64RegClass, MRI);
} else {
I.getOperand(1).ChangeToRegister(AArch64::WZR, false);
RBI.constrainGenericRegister(DefReg, AArch64::GPR32RegClass, MRI);
}
I.setDesc(TII.get(TargetOpcode::COPY));
return true;
}
default:
return false;
}
}
bool AArch64InstructionSelector::select(MachineInstr &I) {
assert(I.getParent() && "Instruction should be in a basic block!");
assert(I.getParent()->getParent() && "Instruction should be in a function!");
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
unsigned Opcode = I.getOpcode();
// G_PHI requires same handling as PHI
if (!isPreISelGenericOpcode(Opcode) || Opcode == TargetOpcode::G_PHI) {
// Certain non-generic instructions also need some special handling.
if (Opcode == TargetOpcode::LOAD_STACK_GUARD)
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
if (Opcode == TargetOpcode::PHI || Opcode == TargetOpcode::G_PHI) {
const Register DefReg = I.getOperand(0).getReg();
const LLT DefTy = MRI.getType(DefReg);
const RegClassOrRegBank &RegClassOrBank =
MRI.getRegClassOrRegBank(DefReg);
const TargetRegisterClass *DefRC
= RegClassOrBank.dyn_cast<const TargetRegisterClass *>();
if (!DefRC) {
if (!DefTy.isValid()) {
LLVM_DEBUG(dbgs() << "PHI operand has no type, not a gvreg?\n");
return false;
}
const RegisterBank &RB = *RegClassOrBank.get<const RegisterBank *>();
DefRC = getRegClassForTypeOnBank(DefTy, RB, RBI);
if (!DefRC) {
LLVM_DEBUG(dbgs() << "PHI operand has unexpected size/bank\n");
return false;
}
}
I.setDesc(TII.get(TargetOpcode::PHI));
return RBI.constrainGenericRegister(DefReg, *DefRC, MRI);
}
if (I.isCopy())
return selectCopy(I, TII, MRI, TRI, RBI);
return true;
}
if (I.getNumOperands() != I.getNumExplicitOperands()) {
LLVM_DEBUG(
dbgs() << "Generic instruction has unexpected implicit operands\n");
return false;
}
// Try to do some lowering before we start instruction selecting. These
// lowerings are purely transformations on the input G_MIR and so selection
// must continue after any modification of the instruction.
preISelLower(I);
// There may be patterns where the importer can't deal with them optimally,
// but does select it to a suboptimal sequence so our custom C++ selection
// code later never has a chance to work on it. Therefore, we have an early
// selection attempt here to give priority to certain selection routines
// over the imported ones.
if (earlySelect(I))
return true;
if (selectImpl(I, *CoverageInfo))
return true;
LLT Ty =
I.getOperand(0).isReg() ? MRI.getType(I.getOperand(0).getReg()) : LLT{};
MachineIRBuilder MIB(I);
switch (Opcode) {
case TargetOpcode::G_BRCOND: {
if (Ty.getSizeInBits() > 32) {
// We shouldn't need this on AArch64, but it would be implemented as an
// EXTRACT_SUBREG followed by a TBNZW because TBNZX has no encoding if the
// bit being tested is < 32.
LLVM_DEBUG(dbgs() << "G_BRCOND has type: " << Ty
<< ", expected at most 32-bits");
return false;
}
const Register CondReg = I.getOperand(0).getReg();
MachineBasicBlock *DestMBB = I.getOperand(1).getMBB();
// Speculation tracking/SLH assumes that optimized TB(N)Z/CB(N)Z
// instructions will not be produced, as they are conditional branch
// instructions that do not set flags.
bool ProduceNonFlagSettingCondBr =
!MF.getFunction().hasFnAttribute(Attribute::SpeculativeLoadHardening);
if (ProduceNonFlagSettingCondBr && selectCompareBranch(I, MF, MRI))
return true;
if (ProduceNonFlagSettingCondBr) {
auto MIB = BuildMI(MBB, I, I.getDebugLoc(), TII.get(AArch64::TBNZW))
.addUse(CondReg)
.addImm(/*bit offset=*/0)
.addMBB(DestMBB);
I.eraseFromParent();
return constrainSelectedInstRegOperands(*MIB.getInstr(), TII, TRI, RBI);
} else {
auto CMP = BuildMI(MBB, I, I.getDebugLoc(), TII.get(AArch64::ANDSWri))
.addDef(AArch64::WZR)
.addUse(CondReg)
.addImm(1);
constrainSelectedInstRegOperands(*CMP.getInstr(), TII, TRI, RBI);
auto Bcc =
BuildMI(MBB, I, I.getDebugLoc(), TII.get(AArch64::Bcc))
.addImm(AArch64CC::EQ)
.addMBB(DestMBB);
I.eraseFromParent();
return constrainSelectedInstRegOperands(*Bcc.getInstr(), TII, TRI, RBI);
}
}
case TargetOpcode::G_BRINDIRECT: {
I.setDesc(TII.get(AArch64::BR));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
case TargetOpcode::G_BRJT:
return selectBrJT(I, MRI);
case TargetOpcode::G_BSWAP: {
// Handle vector types for G_BSWAP directly.
Register DstReg = I.getOperand(0).getReg();
LLT DstTy = MRI.getType(DstReg);
// We should only get vector types here; everything else is handled by the
// importer right now.
if (!DstTy.isVector() || DstTy.getSizeInBits() > 128) {
LLVM_DEBUG(dbgs() << "Dst type for G_BSWAP currently unsupported.\n");
return false;
}
// Only handle 4 and 2 element vectors for now.
// TODO: 16-bit elements.
unsigned NumElts = DstTy.getNumElements();
if (NumElts != 4 && NumElts != 2) {
LLVM_DEBUG(dbgs() << "Unsupported number of elements for G_BSWAP.\n");
return false;
}
// Choose the correct opcode for the supported types. Right now, that's
// v2s32, v4s32, and v2s64.
unsigned Opc = 0;
unsigned EltSize = DstTy.getElementType().getSizeInBits();
if (EltSize == 32)
Opc = (DstTy.getNumElements() == 2) ? AArch64::REV32v8i8
: AArch64::REV32v16i8;
else if (EltSize == 64)
Opc = AArch64::REV64v16i8;
// We should always get something by the time we get here...
assert(Opc != 0 && "Didn't get an opcode for G_BSWAP?");
I.setDesc(TII.get(Opc));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
case TargetOpcode::G_FCONSTANT:
case TargetOpcode::G_CONSTANT: {
const bool isFP = Opcode == TargetOpcode::G_FCONSTANT;
const LLT s8 = LLT::scalar(8);
const LLT s16 = LLT::scalar(16);
const LLT s32 = LLT::scalar(32);
const LLT s64 = LLT::scalar(64);
const LLT p0 = LLT::pointer(0, 64);
const Register DefReg = I.getOperand(0).getReg();
const LLT DefTy = MRI.getType(DefReg);
const unsigned DefSize = DefTy.getSizeInBits();
const RegisterBank &RB = *RBI.getRegBank(DefReg, MRI, TRI);
// FIXME: Redundant check, but even less readable when factored out.
if (isFP) {
if (Ty != s32 && Ty != s64) {
LLVM_DEBUG(dbgs() << "Unable to materialize FP " << Ty
<< " constant, expected: " << s32 << " or " << s64
<< '\n');
return false;
}
if (RB.getID() != AArch64::FPRRegBankID) {
LLVM_DEBUG(dbgs() << "Unable to materialize FP " << Ty
<< " constant on bank: " << RB
<< ", expected: FPR\n");
return false;
}
// The case when we have 0.0 is covered by tablegen. Reject it here so we
// can be sure tablegen works correctly and isn't rescued by this code.
if (I.getOperand(1).getFPImm()->getValueAPF().isExactlyValue(0.0))
return false;
} else {
// s32 and s64 are covered by tablegen.
if (Ty != p0 && Ty != s8 && Ty != s16) {
LLVM_DEBUG(dbgs() << "Unable to materialize integer " << Ty
<< " constant, expected: " << s32 << ", " << s64
<< ", or " << p0 << '\n');
return false;
}
if (RB.getID() != AArch64::GPRRegBankID) {
LLVM_DEBUG(dbgs() << "Unable to materialize integer " << Ty
<< " constant on bank: " << RB
<< ", expected: GPR\n");
return false;
}
}
// We allow G_CONSTANT of types < 32b.
const unsigned MovOpc =
DefSize == 64 ? AArch64::MOVi64imm : AArch64::MOVi32imm;
if (isFP) {
// Either emit a FMOV, or emit a copy to emit a normal mov.
const TargetRegisterClass &GPRRC =
DefSize == 32 ? AArch64::GPR32RegClass : AArch64::GPR64RegClass;
const TargetRegisterClass &FPRRC =
DefSize == 32 ? AArch64::FPR32RegClass : AArch64::FPR64RegClass;
// Can we use a FMOV instruction to represent the immediate?
if (emitFMovForFConstant(I, MRI))
return true;
// Nope. Emit a copy and use a normal mov instead.
const Register DefGPRReg = MRI.createVirtualRegister(&GPRRC);
MachineOperand &RegOp = I.getOperand(0);
RegOp.setReg(DefGPRReg);
MIB.setInsertPt(MIB.getMBB(), std::next(I.getIterator()));
MIB.buildCopy({DefReg}, {DefGPRReg});
if (!RBI.constrainGenericRegister(DefReg, FPRRC, MRI)) {
LLVM_DEBUG(dbgs() << "Failed to constrain G_FCONSTANT def operand\n");
return false;
}
MachineOperand &ImmOp = I.getOperand(1);
// FIXME: Is going through int64_t always correct?
ImmOp.ChangeToImmediate(
ImmOp.getFPImm()->getValueAPF().bitcastToAPInt().getZExtValue());
} else if (I.getOperand(1).isCImm()) {
uint64_t Val = I.getOperand(1).getCImm()->getZExtValue();
I.getOperand(1).ChangeToImmediate(Val);
} else if (I.getOperand(1).isImm()) {
uint64_t Val = I.getOperand(1).getImm();
I.getOperand(1).ChangeToImmediate(Val);
}
I.setDesc(TII.get(MovOpc));
constrainSelectedInstRegOperands(I, TII, TRI, RBI);
return true;
}
case TargetOpcode::G_EXTRACT: {
Register DstReg = I.getOperand(0).getReg();
Register SrcReg = I.getOperand(1).getReg();
LLT SrcTy = MRI.getType(SrcReg);
LLT DstTy = MRI.getType(DstReg);
(void)DstTy;
unsigned SrcSize = SrcTy.getSizeInBits();
if (SrcTy.getSizeInBits() > 64) {
// This should be an extract of an s128, which is like a vector extract.
if (SrcTy.getSizeInBits() != 128)
return false;
// Only support extracting 64 bits from an s128 at the moment.
if (DstTy.getSizeInBits() != 64)
return false;
const RegisterBank &SrcRB = *RBI.getRegBank(SrcReg, MRI, TRI);
const RegisterBank &DstRB = *RBI.getRegBank(DstReg, MRI, TRI);
// Check we have the right regbank always.
assert(SrcRB.getID() == AArch64::FPRRegBankID &&
DstRB.getID() == AArch64::FPRRegBankID &&
"Wrong extract regbank!");
(void)SrcRB;
// Emit the same code as a vector extract.
// Offset must be a multiple of 64.
unsigned Offset = I.getOperand(2).getImm();
if (Offset % 64 != 0)
return false;
unsigned LaneIdx = Offset / 64;
MachineIRBuilder MIB(I);
MachineInstr *Extract = emitExtractVectorElt(
DstReg, DstRB, LLT::scalar(64), SrcReg, LaneIdx, MIB);
if (!Extract)
return false;
I.eraseFromParent();
return true;
}
I.setDesc(TII.get(SrcSize == 64 ? AArch64::UBFMXri : AArch64::UBFMWri));
MachineInstrBuilder(MF, I).addImm(I.getOperand(2).getImm() +
Ty.getSizeInBits() - 1);
if (SrcSize < 64) {
assert(SrcSize == 32 && DstTy.getSizeInBits() == 16 &&
"unexpected G_EXTRACT types");
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
DstReg = MRI.createGenericVirtualRegister(LLT::scalar(64));
MIB.setInsertPt(MIB.getMBB(), std::next(I.getIterator()));
MIB.buildInstr(TargetOpcode::COPY, {I.getOperand(0).getReg()}, {})
.addReg(DstReg, 0, AArch64::sub_32);
RBI.constrainGenericRegister(I.getOperand(0).getReg(),
AArch64::GPR32RegClass, MRI);
I.getOperand(0).setReg(DstReg);
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
case TargetOpcode::G_INSERT: {
LLT SrcTy = MRI.getType(I.getOperand(2).getReg());
LLT DstTy = MRI.getType(I.getOperand(0).getReg());
unsigned DstSize = DstTy.getSizeInBits();
// Larger inserts are vectors, same-size ones should be something else by
// now (split up or turned into COPYs).
if (Ty.getSizeInBits() > 64 || SrcTy.getSizeInBits() > 32)
return false;
I.setDesc(TII.get(DstSize == 64 ? AArch64::BFMXri : AArch64::BFMWri));
unsigned LSB = I.getOperand(3).getImm();
unsigned Width = MRI.getType(I.getOperand(2).getReg()).getSizeInBits();
I.getOperand(3).setImm((DstSize - LSB) % DstSize);
MachineInstrBuilder(MF, I).addImm(Width - 1);
if (DstSize < 64) {
assert(DstSize == 32 && SrcTy.getSizeInBits() == 16 &&
"unexpected G_INSERT types");
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
Register SrcReg = MRI.createGenericVirtualRegister(LLT::scalar(64));
BuildMI(MBB, I.getIterator(), I.getDebugLoc(),
TII.get(AArch64::SUBREG_TO_REG))
.addDef(SrcReg)
.addImm(0)
.addUse(I.getOperand(2).getReg())
.addImm(AArch64::sub_32);
RBI.constrainGenericRegister(I.getOperand(2).getReg(),
AArch64::GPR32RegClass, MRI);
I.getOperand(2).setReg(SrcReg);
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
case TargetOpcode::G_FRAME_INDEX: {
// allocas and G_FRAME_INDEX are only supported in addrspace(0).
if (Ty != LLT::pointer(0, 64)) {
LLVM_DEBUG(dbgs() << "G_FRAME_INDEX pointer has type: " << Ty
<< ", expected: " << LLT::pointer(0, 64) << '\n');
return false;
}
I.setDesc(TII.get(AArch64::ADDXri));
// MOs for a #0 shifted immediate.
I.addOperand(MachineOperand::CreateImm(0));
I.addOperand(MachineOperand::CreateImm(0));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
case TargetOpcode::G_GLOBAL_VALUE: {
auto GV = I.getOperand(1).getGlobal();
if (GV->isThreadLocal())
return selectTLSGlobalValue(I, MRI);
unsigned OpFlags = STI.ClassifyGlobalReference(GV, TM);
if (OpFlags & AArch64II::MO_GOT) {
I.setDesc(TII.get(AArch64::LOADgot));
I.getOperand(1).setTargetFlags(OpFlags);
} else if (TM.getCodeModel() == CodeModel::Large) {
// Materialize the global using movz/movk instructions.
materializeLargeCMVal(I, GV, OpFlags);
I.eraseFromParent();
return true;
} else if (TM.getCodeModel() == CodeModel::Tiny) {
I.setDesc(TII.get(AArch64::ADR));
I.getOperand(1).setTargetFlags(OpFlags);
} else {
I.setDesc(TII.get(AArch64::MOVaddr));
I.getOperand(1).setTargetFlags(OpFlags | AArch64II::MO_PAGE);
MachineInstrBuilder MIB(MF, I);
MIB.addGlobalAddress(GV, I.getOperand(1).getOffset(),
OpFlags | AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
}
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
case TargetOpcode::G_ZEXTLOAD:
case TargetOpcode::G_LOAD:
case TargetOpcode::G_STORE: {
bool IsZExtLoad = I.getOpcode() == TargetOpcode::G_ZEXTLOAD;
MachineIRBuilder MIB(I);
LLT PtrTy = MRI.getType(I.getOperand(1).getReg());
if (PtrTy != LLT::pointer(0, 64)) {
LLVM_DEBUG(dbgs() << "Load/Store pointer has type: " << PtrTy
<< ", expected: " << LLT::pointer(0, 64) << '\n');
return false;
}
auto &MemOp = **I.memoperands_begin();
if (MemOp.isAtomic()) {
// For now we just support s8 acquire loads to be able to compile stack
// protector code.
if (MemOp.getOrdering() == AtomicOrdering::Acquire &&
MemOp.getSize() == 1) {
I.setDesc(TII.get(AArch64::LDARB));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
LLVM_DEBUG(dbgs() << "Atomic load/store not fully supported yet\n");
return false;
}
unsigned MemSizeInBits = MemOp.getSize() * 8;
const Register PtrReg = I.getOperand(1).getReg();
#ifndef NDEBUG
const RegisterBank &PtrRB = *RBI.getRegBank(PtrReg, MRI, TRI);
// Sanity-check the pointer register.
assert(PtrRB.getID() == AArch64::GPRRegBankID &&
"Load/Store pointer operand isn't a GPR");
assert(MRI.getType(PtrReg).isPointer() &&
"Load/Store pointer operand isn't a pointer");
#endif
const Register ValReg = I.getOperand(0).getReg();
const RegisterBank &RB = *RBI.getRegBank(ValReg, MRI, TRI);
const unsigned NewOpc =
selectLoadStoreUIOp(I.getOpcode(), RB.getID(), MemSizeInBits);
if (NewOpc == I.getOpcode())
return false;
I.setDesc(TII.get(NewOpc));
uint64_t Offset = 0;
auto *PtrMI = MRI.getVRegDef(PtrReg);
// Try to fold a GEP into our unsigned immediate addressing mode.
if (PtrMI->getOpcode() == TargetOpcode::G_PTR_ADD) {
if (auto COff = getConstantVRegVal(PtrMI->getOperand(2).getReg(), MRI)) {
int64_t Imm = *COff;
const unsigned Size = MemSizeInBits / 8;
const unsigned Scale = Log2_32(Size);
if ((Imm & (Size - 1)) == 0 && Imm >= 0 && Imm < (0x1000 << Scale)) {
Register Ptr2Reg = PtrMI->getOperand(1).getReg();
I.getOperand(1).setReg(Ptr2Reg);
PtrMI = MRI.getVRegDef(Ptr2Reg);
Offset = Imm / Size;
}
}
}
// If we haven't folded anything into our addressing mode yet, try to fold
// a frame index into the base+offset.
if (!Offset && PtrMI->getOpcode() == TargetOpcode::G_FRAME_INDEX)
I.getOperand(1).ChangeToFrameIndex(PtrMI->getOperand(1).getIndex());
I.addOperand(MachineOperand::CreateImm(Offset));
// If we're storing a 0, use WZR/XZR.
if (auto CVal = getConstantVRegVal(ValReg, MRI)) {
if (*CVal == 0 && Opcode == TargetOpcode::G_STORE) {
if (I.getOpcode() == AArch64::STRWui)
I.getOperand(0).setReg(AArch64::WZR);
else if (I.getOpcode() == AArch64::STRXui)
I.getOperand(0).setReg(AArch64::XZR);
}
}
if (IsZExtLoad) {
// The zextload from a smaller type to i32 should be handled by the importer.
if (MRI.getType(ValReg).getSizeInBits() != 64)
return false;
// If we have a ZEXTLOAD then change the load's type to be a narrower reg
//and zero_extend with SUBREG_TO_REG.
Register LdReg = MRI.createVirtualRegister(&AArch64::GPR32RegClass);
Register DstReg = I.getOperand(0).getReg();
I.getOperand(0).setReg(LdReg);
MIB.setInsertPt(MIB.getMBB(), std::next(I.getIterator()));
MIB.buildInstr(AArch64::SUBREG_TO_REG, {DstReg}, {})
.addImm(0)
.addUse(LdReg)
.addImm(AArch64::sub_32);
constrainSelectedInstRegOperands(I, TII, TRI, RBI);
return RBI.constrainGenericRegister(DstReg, AArch64::GPR64allRegClass,
MRI);
}
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
case TargetOpcode::G_SMULH:
case TargetOpcode::G_UMULH: {
// Reject the various things we don't support yet.
if (unsupportedBinOp(I, RBI, MRI, TRI))
return false;
const Register DefReg = I.getOperand(0).getReg();
const RegisterBank &RB = *RBI.getRegBank(DefReg, MRI, TRI);
if (RB.getID() != AArch64::GPRRegBankID) {
LLVM_DEBUG(dbgs() << "G_[SU]MULH on bank: " << RB << ", expected: GPR\n");
return false;
}
if (Ty != LLT::scalar(64)) {
LLVM_DEBUG(dbgs() << "G_[SU]MULH has type: " << Ty
<< ", expected: " << LLT::scalar(64) << '\n');
return false;
}
unsigned NewOpc = I.getOpcode() == TargetOpcode::G_SMULH ? AArch64::SMULHrr
: AArch64::UMULHrr;
I.setDesc(TII.get(NewOpc));
// Now that we selected an opcode, we need to constrain the register
// operands to use appropriate classes.
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
case TargetOpcode::G_FADD:
case TargetOpcode::G_FSUB:
case TargetOpcode::G_FMUL:
case TargetOpcode::G_FDIV:
case TargetOpcode::G_ASHR:
if (MRI.getType(I.getOperand(0).getReg()).isVector())
return selectVectorASHR(I, MRI);
LLVM_FALLTHROUGH;
case TargetOpcode::G_SHL:
if (Opcode == TargetOpcode::G_SHL &&
MRI.getType(I.getOperand(0).getReg()).isVector())
return selectVectorSHL(I, MRI);
LLVM_FALLTHROUGH;
case TargetOpcode::G_OR:
case TargetOpcode::G_LSHR: {
// Reject the various things we don't support yet.
if (unsupportedBinOp(I, RBI, MRI, TRI))
return false;
const unsigned OpSize = Ty.getSizeInBits();
const Register DefReg = I.getOperand(0).getReg();
const RegisterBank &RB = *RBI.getRegBank(DefReg, MRI, TRI);
const unsigned NewOpc = selectBinaryOp(I.getOpcode(), RB.getID(), OpSize);
if (NewOpc == I.getOpcode())
return false;
I.setDesc(TII.get(NewOpc));
// FIXME: Should the type be always reset in setDesc?
// Now that we selected an opcode, we need to constrain the register
// operands to use appropriate classes.
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
case TargetOpcode::G_PTR_ADD: {
MachineIRBuilder MIRBuilder(I);
emitADD(I.getOperand(0).getReg(), I.getOperand(1), I.getOperand(2),
MIRBuilder);
I.eraseFromParent();
return true;
}
case TargetOpcode::G_UADDO: {
// TODO: Support other types.
unsigned OpSize = Ty.getSizeInBits();
if (OpSize != 32 && OpSize != 64) {
LLVM_DEBUG(
dbgs()
<< "G_UADDO currently only supported for 32 and 64 b types.\n");
return false;
}
// TODO: Support vectors.
if (Ty.isVector()) {
LLVM_DEBUG(dbgs() << "G_UADDO currently only supported for scalars.\n");
return false;
}
// Add and set the set condition flag.
unsigned AddsOpc = OpSize == 32 ? AArch64::ADDSWrr : AArch64::ADDSXrr;
MachineIRBuilder MIRBuilder(I);
auto AddsMI = MIRBuilder.buildInstr(
AddsOpc, {I.getOperand(0).getReg()},
{I.getOperand(2).getReg(), I.getOperand(3).getReg()});
constrainSelectedInstRegOperands(*AddsMI, TII, TRI, RBI);
// Now, put the overflow result in the register given by the first operand
// to the G_UADDO. CSINC increments the result when the predicate is false,
// so to get the increment when it's true, we need to use the inverse. In
// this case, we want to increment when carry is set.
auto CsetMI = MIRBuilder
.buildInstr(AArch64::CSINCWr, {I.getOperand(1).getReg()},
{Register(AArch64::WZR), Register(AArch64::WZR)})
.addImm(getInvertedCondCode(AArch64CC::HS));
constrainSelectedInstRegOperands(*CsetMI, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
case TargetOpcode::G_PTR_MASK: {
uint64_t Align = I.getOperand(2).getImm();
if (Align >= 64 || Align == 0)
return false;
uint64_t Mask = ~((1ULL << Align) - 1);
I.setDesc(TII.get(AArch64::ANDXri));
I.getOperand(2).setImm(AArch64_AM::encodeLogicalImmediate(Mask, 64));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
case TargetOpcode::G_PTRTOINT:
case TargetOpcode::G_TRUNC: {
const LLT DstTy = MRI.getType(I.getOperand(0).getReg());
const LLT SrcTy = MRI.getType(I.getOperand(1).getReg());
const Register DstReg = I.getOperand(0).getReg();
const Register SrcReg = I.getOperand(1).getReg();
const RegisterBank &DstRB = *RBI.getRegBank(DstReg, MRI, TRI);
const RegisterBank &SrcRB = *RBI.getRegBank(SrcReg, MRI, TRI);
if (DstRB.getID() != SrcRB.getID()) {
LLVM_DEBUG(
dbgs() << "G_TRUNC/G_PTRTOINT input/output on different banks\n");
return false;
}
if (DstRB.getID() == AArch64::GPRRegBankID) {
const TargetRegisterClass *DstRC =
getRegClassForTypeOnBank(DstTy, DstRB, RBI);
if (!DstRC)
return false;
const TargetRegisterClass *SrcRC =
getRegClassForTypeOnBank(SrcTy, SrcRB, RBI);
if (!SrcRC)
return false;
if (!RBI.constrainGenericRegister(SrcReg, *SrcRC, MRI) ||
!RBI.constrainGenericRegister(DstReg, *DstRC, MRI)) {
LLVM_DEBUG(dbgs() << "Failed to constrain G_TRUNC/G_PTRTOINT\n");
return false;
}
if (DstRC == SrcRC) {
// Nothing to be done
} else if (Opcode == TargetOpcode::G_TRUNC && DstTy == LLT::scalar(32) &&
SrcTy == LLT::scalar(64)) {
llvm_unreachable("TableGen can import this case");
return false;
} else if (DstRC == &AArch64::GPR32RegClass &&
SrcRC == &AArch64::GPR64RegClass) {
I.getOperand(1).setSubReg(AArch64::sub_32);
} else {
LLVM_DEBUG(
dbgs() << "Unhandled mismatched classes in G_TRUNC/G_PTRTOINT\n");
return false;
}
I.setDesc(TII.get(TargetOpcode::COPY));
return true;
} else if (DstRB.getID() == AArch64::FPRRegBankID) {
if (DstTy == LLT::vector(4, 16) && SrcTy == LLT::vector(4, 32)) {
I.setDesc(TII.get(AArch64::XTNv4i16));
constrainSelectedInstRegOperands(I, TII, TRI, RBI);
return true;
}
if (!SrcTy.isVector() && SrcTy.getSizeInBits() == 128) {
MachineIRBuilder MIB(I);
MachineInstr *Extract = emitExtractVectorElt(
DstReg, DstRB, LLT::scalar(DstTy.getSizeInBits()), SrcReg, 0, MIB);
if (!Extract)
return false;
I.eraseFromParent();
return true;
}
}
return false;
}
case TargetOpcode::G_ANYEXT: {
const Register DstReg = I.getOperand(0).getReg();
const Register SrcReg = I.getOperand(1).getReg();
const RegisterBank &RBDst = *RBI.getRegBank(DstReg, MRI, TRI);
if (RBDst.getID() != AArch64::GPRRegBankID) {
LLVM_DEBUG(dbgs() << "G_ANYEXT on bank: " << RBDst
<< ", expected: GPR\n");
return false;
}
const RegisterBank &RBSrc = *RBI.getRegBank(SrcReg, MRI, TRI);
if (RBSrc.getID() != AArch64::GPRRegBankID) {
LLVM_DEBUG(dbgs() << "G_ANYEXT on bank: " << RBSrc
<< ", expected: GPR\n");
return false;
}
const unsigned DstSize = MRI.getType(DstReg).getSizeInBits();
if (DstSize == 0) {
LLVM_DEBUG(dbgs() << "G_ANYEXT operand has no size, not a gvreg?\n");
return false;
}
if (DstSize != 64 && DstSize > 32) {
LLVM_DEBUG(dbgs() << "G_ANYEXT to size: " << DstSize
<< ", expected: 32 or 64\n");
return false;
}
// At this point G_ANYEXT is just like a plain COPY, but we need
// to explicitly form the 64-bit value if any.
if (DstSize > 32) {
Register ExtSrc = MRI.createVirtualRegister(&AArch64::GPR64allRegClass);
BuildMI(MBB, I, I.getDebugLoc(), TII.get(AArch64::SUBREG_TO_REG))
.addDef(ExtSrc)
.addImm(0)
.addUse(SrcReg)
.addImm(AArch64::sub_32);
I.getOperand(1).setReg(ExtSrc);
}
return selectCopy(I, TII, MRI, TRI, RBI);
}
case TargetOpcode::G_ZEXT:
case TargetOpcode::G_SEXT: {
unsigned Opcode = I.getOpcode();
const bool IsSigned = Opcode == TargetOpcode::G_SEXT;
const Register DefReg = I.getOperand(0).getReg();
const Register SrcReg = I.getOperand(1).getReg();
const LLT DstTy = MRI.getType(DefReg);
const LLT SrcTy = MRI.getType(SrcReg);
unsigned DstSize = DstTy.getSizeInBits();
unsigned SrcSize = SrcTy.getSizeInBits();
if (DstTy.isVector())
return false; // Should be handled by imported patterns.
assert((*RBI.getRegBank(DefReg, MRI, TRI)).getID() ==
AArch64::GPRRegBankID &&
"Unexpected ext regbank");
MachineIRBuilder MIB(I);
MachineInstr *ExtI;
// First check if we're extending the result of a load which has a dest type
// smaller than 32 bits, then this zext is redundant. GPR32 is the smallest
// GPR register on AArch64 and all loads which are smaller automatically
// zero-extend the upper bits. E.g.
// %v(s8) = G_LOAD %p, :: (load 1)
// %v2(s32) = G_ZEXT %v(s8)
if (!IsSigned) {
auto *LoadMI = getOpcodeDef(TargetOpcode::G_LOAD, SrcReg, MRI);
if (LoadMI &&
RBI.getRegBank(SrcReg, MRI, TRI)->getID() == AArch64::GPRRegBankID) {
const MachineMemOperand *MemOp = *LoadMI->memoperands_begin();
unsigned BytesLoaded = MemOp->getSize();
if (BytesLoaded < 4 && SrcTy.getSizeInBytes() == BytesLoaded)
return selectCopy(I, TII, MRI, TRI, RBI);
}
}
if (DstSize == 64) {
// FIXME: Can we avoid manually doing this?
if (!RBI.constrainGenericRegister(SrcReg, AArch64::GPR32RegClass, MRI)) {
LLVM_DEBUG(dbgs() << "Failed to constrain " << TII.getName(Opcode)
<< " operand\n");
return false;
}
auto SubregToReg =
MIB.buildInstr(AArch64::SUBREG_TO_REG, {&AArch64::GPR64RegClass}, {})
.addImm(0)
.addUse(SrcReg)
.addImm(AArch64::sub_32);
ExtI = MIB.buildInstr(IsSigned ? AArch64::SBFMXri : AArch64::UBFMXri,
{DefReg}, {SubregToReg})
.addImm(0)
.addImm(SrcSize - 1);
} else if (DstSize <= 32) {
ExtI = MIB.buildInstr(IsSigned ? AArch64::SBFMWri : AArch64::UBFMWri,
{DefReg}, {SrcReg})
.addImm(0)
.addImm(SrcSize - 1);
} else {
return false;
}
constrainSelectedInstRegOperands(*ExtI, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
case TargetOpcode::G_SITOFP:
case TargetOpcode::G_UITOFP:
case TargetOpcode::G_FPTOSI:
case TargetOpcode::G_FPTOUI: {
const LLT DstTy = MRI.getType(I.getOperand(0).getReg()),
SrcTy = MRI.getType(I.getOperand(1).getReg());
const unsigned NewOpc = selectFPConvOpc(Opcode, DstTy, SrcTy);
if (NewOpc == Opcode)
return false;
I.setDesc(TII.get(NewOpc));
constrainSelectedInstRegOperands(I, TII, TRI, RBI);
return true;
}
case TargetOpcode::G_INTTOPTR:
// The importer is currently unable to import pointer types since they
// didn't exist in SelectionDAG.
return selectCopy(I, TII, MRI, TRI, RBI);
case TargetOpcode::G_BITCAST:
// Imported SelectionDAG rules can handle every bitcast except those that
// bitcast from a type to the same type. Ideally, these shouldn't occur
// but we might not run an optimizer that deletes them. The other exception
// is bitcasts involving pointer types, as SelectionDAG has no knowledge
// of them.
return selectCopy(I, TII, MRI, TRI, RBI);
case TargetOpcode::G_SELECT: {
if (MRI.getType(I.getOperand(1).getReg()) != LLT::scalar(1)) {
LLVM_DEBUG(dbgs() << "G_SELECT cond has type: " << Ty
<< ", expected: " << LLT::scalar(1) << '\n');
return false;
}
const Register CondReg = I.getOperand(1).getReg();
const Register TReg = I.getOperand(2).getReg();
const Register FReg = I.getOperand(3).getReg();
if (tryOptSelect(I))
return true;
Register CSelOpc = selectSelectOpc(I, MRI, RBI);
MachineInstr &TstMI =
*BuildMI(MBB, I, I.getDebugLoc(), TII.get(AArch64::ANDSWri))
.addDef(AArch64::WZR)
.addUse(CondReg)
.addImm(AArch64_AM::encodeLogicalImmediate(1, 32));
MachineInstr &CSelMI = *BuildMI(MBB, I, I.getDebugLoc(), TII.get(CSelOpc))
.addDef(I.getOperand(0).getReg())
.addUse(TReg)
.addUse(FReg)
.addImm(AArch64CC::NE);
constrainSelectedInstRegOperands(TstMI, TII, TRI, RBI);
constrainSelectedInstRegOperands(CSelMI, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
case TargetOpcode::G_ICMP: {
if (Ty.isVector())
return selectVectorICmp(I, MRI);
if (Ty != LLT::scalar(32)) {
LLVM_DEBUG(dbgs() << "G_ICMP result has type: " << Ty
<< ", expected: " << LLT::scalar(32) << '\n');
return false;
}
MachineIRBuilder MIRBuilder(I);
if (!emitIntegerCompare(I.getOperand(2), I.getOperand(3), I.getOperand(1),
MIRBuilder))
return false;
emitCSetForICMP(I.getOperand(0).getReg(), I.getOperand(1).getPredicate(),
MIRBuilder);
I.eraseFromParent();
return true;
}
case TargetOpcode::G_FCMP: {
if (Ty != LLT::scalar(32)) {
LLVM_DEBUG(dbgs() << "G_FCMP result has type: " << Ty
<< ", expected: " << LLT::scalar(32) << '\n');
return false;
}
unsigned CmpOpc = selectFCMPOpc(I, MRI);
if (!CmpOpc)
return false;
// FIXME: regbank
AArch64CC::CondCode CC1, CC2;
changeFCMPPredToAArch64CC(
(CmpInst::Predicate)I.getOperand(1).getPredicate(), CC1, CC2);
// Partially build the compare. Decide if we need to add a use for the
// third operand based off whether or not we're comparing against 0.0.
auto CmpMI = BuildMI(MBB, I, I.getDebugLoc(), TII.get(CmpOpc))
.addUse(I.getOperand(2).getReg());
// If we don't have an immediate compare, then we need to add a use of the
// register which wasn't used for the immediate.
// Note that the immediate will always be the last operand.
if (CmpOpc != AArch64::FCMPSri && CmpOpc != AArch64::FCMPDri)
CmpMI = CmpMI.addUse(I.getOperand(3).getReg());
const Register DefReg = I.getOperand(0).getReg();
Register Def1Reg = DefReg;
if (CC2 != AArch64CC::AL)
Def1Reg = MRI.createVirtualRegister(&AArch64::GPR32RegClass);
MachineInstr &CSetMI =
*BuildMI(MBB, I, I.getDebugLoc(), TII.get(AArch64::CSINCWr))
.addDef(Def1Reg)
.addUse(AArch64::WZR)
.addUse(AArch64::WZR)
.addImm(getInvertedCondCode(CC1));
if (CC2 != AArch64CC::AL) {
Register Def2Reg = MRI.createVirtualRegister(&AArch64::GPR32RegClass);
MachineInstr &CSet2MI =
*BuildMI(MBB, I, I.getDebugLoc(), TII.get(AArch64::CSINCWr))
.addDef(Def2Reg)
.addUse(AArch64::WZR)
.addUse(AArch64::WZR)
.addImm(getInvertedCondCode(CC2));
MachineInstr &OrMI =
*BuildMI(MBB, I, I.getDebugLoc(), TII.get(AArch64::ORRWrr))
.addDef(DefReg)
.addUse(Def1Reg)
.addUse(Def2Reg);
constrainSelectedInstRegOperands(OrMI, TII, TRI, RBI);
constrainSelectedInstRegOperands(CSet2MI, TII, TRI, RBI);
}
constrainSelectedInstRegOperands(*CmpMI, TII, TRI, RBI);
constrainSelectedInstRegOperands(CSetMI, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
case TargetOpcode::G_VASTART:
return STI.isTargetDarwin() ? selectVaStartDarwin(I, MF, MRI)
: selectVaStartAAPCS(I, MF, MRI);
case TargetOpcode::G_INTRINSIC:
return selectIntrinsic(I, MRI);
case TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS:
return selectIntrinsicWithSideEffects(I, MRI);
case TargetOpcode::G_IMPLICIT_DEF: {
I.setDesc(TII.get(TargetOpcode::IMPLICIT_DEF));
const LLT DstTy = MRI.getType(I.getOperand(0).getReg());
const Register DstReg = I.getOperand(0).getReg();
const RegisterBank &DstRB = *RBI.getRegBank(DstReg, MRI, TRI);
const TargetRegisterClass *DstRC =
getRegClassForTypeOnBank(DstTy, DstRB, RBI);
RBI.constrainGenericRegister(DstReg, *DstRC, MRI);
return true;
}
case TargetOpcode::G_BLOCK_ADDR: {
if (TM.getCodeModel() == CodeModel::Large) {
materializeLargeCMVal(I, I.getOperand(1).getBlockAddress(), 0);
I.eraseFromParent();
return true;
} else {
I.setDesc(TII.get(AArch64::MOVaddrBA));
auto MovMI = BuildMI(MBB, I, I.getDebugLoc(), TII.get(AArch64::MOVaddrBA),
I.getOperand(0).getReg())
.addBlockAddress(I.getOperand(1).getBlockAddress(),
/* Offset */ 0, AArch64II::MO_PAGE)
.addBlockAddress(
I.getOperand(1).getBlockAddress(), /* Offset */ 0,
AArch64II::MO_NC | AArch64II::MO_PAGEOFF);
I.eraseFromParent();
return constrainSelectedInstRegOperands(*MovMI, TII, TRI, RBI);
}
}
case TargetOpcode::G_INTRINSIC_TRUNC:
return selectIntrinsicTrunc(I, MRI);
case TargetOpcode::G_INTRINSIC_ROUND:
return selectIntrinsicRound(I, MRI);
case TargetOpcode::G_BUILD_VECTOR:
return selectBuildVector(I, MRI);
case TargetOpcode::G_MERGE_VALUES:
return selectMergeValues(I, MRI);
case TargetOpcode::G_UNMERGE_VALUES:
return selectUnmergeValues(I, MRI);
case TargetOpcode::G_SHUFFLE_VECTOR:
return selectShuffleVector(I, MRI);
case TargetOpcode::G_EXTRACT_VECTOR_ELT:
return selectExtractElt(I, MRI);
case TargetOpcode::G_INSERT_VECTOR_ELT:
return selectInsertElt(I, MRI);
case TargetOpcode::G_CONCAT_VECTORS:
return selectConcatVectors(I, MRI);
case TargetOpcode::G_JUMP_TABLE:
return selectJumpTable(I, MRI);
}
return false;
}
bool AArch64InstructionSelector::selectBrJT(MachineInstr &I,
MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_BRJT && "Expected G_BRJT");
Register JTAddr = I.getOperand(0).getReg();
unsigned JTI = I.getOperand(1).getIndex();
Register Index = I.getOperand(2).getReg();
MachineIRBuilder MIB(I);
Register TargetReg = MRI.createVirtualRegister(&AArch64::GPR64RegClass);
Register ScratchReg = MRI.createVirtualRegister(&AArch64::GPR64spRegClass);
MIB.buildInstr(AArch64::JumpTableDest32, {TargetReg, ScratchReg},
{JTAddr, Index})
.addJumpTableIndex(JTI);
// Build the indirect branch.
MIB.buildInstr(AArch64::BR, {}, {TargetReg});
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectJumpTable(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_JUMP_TABLE && "Expected jump table");
assert(I.getOperand(1).isJTI() && "Jump table op should have a JTI!");
Register DstReg = I.getOperand(0).getReg();
unsigned JTI = I.getOperand(1).getIndex();
// We generate a MOVaddrJT which will get expanded to an ADRP + ADD later.
MachineIRBuilder MIB(I);
auto MovMI =
MIB.buildInstr(AArch64::MOVaddrJT, {DstReg}, {})
.addJumpTableIndex(JTI, AArch64II::MO_PAGE)
.addJumpTableIndex(JTI, AArch64II::MO_NC | AArch64II::MO_PAGEOFF);
I.eraseFromParent();
return constrainSelectedInstRegOperands(*MovMI, TII, TRI, RBI);
}
bool AArch64InstructionSelector::selectTLSGlobalValue(
MachineInstr &I, MachineRegisterInfo &MRI) const {
if (!STI.isTargetMachO())
return false;
MachineFunction &MF = *I.getParent()->getParent();
MF.getFrameInfo().setAdjustsStack(true);
const GlobalValue &GV = *I.getOperand(1).getGlobal();
MachineIRBuilder MIB(I);
MIB.buildInstr(AArch64::LOADgot, {AArch64::X0}, {})
.addGlobalAddress(&GV, 0, AArch64II::MO_TLS);
auto Load = MIB.buildInstr(AArch64::LDRXui, {&AArch64::GPR64commonRegClass},
{Register(AArch64::X0)})
.addImm(0);
// TLS calls preserve all registers except those that absolutely must be
// trashed: X0 (it takes an argument), LR (it's a call) and NZCV (let's not be
// silly).
MIB.buildInstr(AArch64::BLR, {}, {Load})
.addDef(AArch64::X0, RegState::Implicit)
.addRegMask(TRI.getTLSCallPreservedMask());
MIB.buildCopy(I.getOperand(0).getReg(), Register(AArch64::X0));
RBI.constrainGenericRegister(I.getOperand(0).getReg(), AArch64::GPR64RegClass,
MRI);
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectIntrinsicTrunc(
MachineInstr &I, MachineRegisterInfo &MRI) const {
const LLT SrcTy = MRI.getType(I.getOperand(0).getReg());
// Select the correct opcode.
unsigned Opc = 0;
if (!SrcTy.isVector()) {
switch (SrcTy.getSizeInBits()) {
default:
case 16:
Opc = AArch64::FRINTZHr;
break;
case 32:
Opc = AArch64::FRINTZSr;
break;
case 64:
Opc = AArch64::FRINTZDr;
break;
}
} else {
unsigned NumElts = SrcTy.getNumElements();
switch (SrcTy.getElementType().getSizeInBits()) {
default:
break;
case 16:
if (NumElts == 4)
Opc = AArch64::FRINTZv4f16;
else if (NumElts == 8)
Opc = AArch64::FRINTZv8f16;
break;
case 32:
if (NumElts == 2)
Opc = AArch64::FRINTZv2f32;
else if (NumElts == 4)
Opc = AArch64::FRINTZv4f32;
break;
case 64:
if (NumElts == 2)
Opc = AArch64::FRINTZv2f64;
break;
}
}
if (!Opc) {
// Didn't get an opcode above, bail.
LLVM_DEBUG(dbgs() << "Unsupported type for G_INTRINSIC_TRUNC!\n");
return false;
}
// Legalization would have set us up perfectly for this; we just need to
// set the opcode and move on.
I.setDesc(TII.get(Opc));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
bool AArch64InstructionSelector::selectIntrinsicRound(
MachineInstr &I, MachineRegisterInfo &MRI) const {
const LLT SrcTy = MRI.getType(I.getOperand(0).getReg());
// Select the correct opcode.
unsigned Opc = 0;
if (!SrcTy.isVector()) {
switch (SrcTy.getSizeInBits()) {
default:
case 16:
Opc = AArch64::FRINTAHr;
break;
case 32:
Opc = AArch64::FRINTASr;
break;
case 64:
Opc = AArch64::FRINTADr;
break;
}
} else {
unsigned NumElts = SrcTy.getNumElements();
switch (SrcTy.getElementType().getSizeInBits()) {
default:
break;
case 16:
if (NumElts == 4)
Opc = AArch64::FRINTAv4f16;
else if (NumElts == 8)
Opc = AArch64::FRINTAv8f16;
break;
case 32:
if (NumElts == 2)
Opc = AArch64::FRINTAv2f32;
else if (NumElts == 4)
Opc = AArch64::FRINTAv4f32;
break;
case 64:
if (NumElts == 2)
Opc = AArch64::FRINTAv2f64;
break;
}
}
if (!Opc) {
// Didn't get an opcode above, bail.
LLVM_DEBUG(dbgs() << "Unsupported type for G_INTRINSIC_ROUND!\n");
return false;
}
// Legalization would have set us up perfectly for this; we just need to
// set the opcode and move on.
I.setDesc(TII.get(Opc));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
bool AArch64InstructionSelector::selectVectorICmp(
MachineInstr &I, MachineRegisterInfo &MRI) const {
Register DstReg = I.getOperand(0).getReg();
LLT DstTy = MRI.getType(DstReg);
Register SrcReg = I.getOperand(2).getReg();
Register Src2Reg = I.getOperand(3).getReg();
LLT SrcTy = MRI.getType(SrcReg);
unsigned SrcEltSize = SrcTy.getElementType().getSizeInBits();
unsigned NumElts = DstTy.getNumElements();
// First index is element size, 0 == 8b, 1 == 16b, 2 == 32b, 3 == 64b
// Second index is num elts, 0 == v2, 1 == v4, 2 == v8, 3 == v16
// Third index is cc opcode:
// 0 == eq
// 1 == ugt
// 2 == uge
// 3 == ult
// 4 == ule
// 5 == sgt
// 6 == sge
// 7 == slt
// 8 == sle
// ne is done by negating 'eq' result.
// This table below assumes that for some comparisons the operands will be
// commuted.
// ult op == commute + ugt op
// ule op == commute + uge op
// slt op == commute + sgt op
// sle op == commute + sge op
unsigned PredIdx = 0;
bool SwapOperands = false;
CmpInst::Predicate Pred = (CmpInst::Predicate)I.getOperand(1).getPredicate();
switch (Pred) {
case CmpInst::ICMP_NE:
case CmpInst::ICMP_EQ:
PredIdx = 0;
break;
case CmpInst::ICMP_UGT:
PredIdx = 1;
break;
case CmpInst::ICMP_UGE:
PredIdx = 2;
break;
case CmpInst::ICMP_ULT:
PredIdx = 3;
SwapOperands = true;
break;
case CmpInst::ICMP_ULE:
PredIdx = 4;
SwapOperands = true;
break;
case CmpInst::ICMP_SGT:
PredIdx = 5;
break;
case CmpInst::ICMP_SGE:
PredIdx = 6;
break;
case CmpInst::ICMP_SLT:
PredIdx = 7;
SwapOperands = true;
break;
case CmpInst::ICMP_SLE:
PredIdx = 8;
SwapOperands = true;
break;
default:
llvm_unreachable("Unhandled icmp predicate");
return false;
}
// This table obviously should be tablegen'd when we have our GISel native
// tablegen selector.
static const unsigned OpcTable[4][4][9] = {
{
{0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */},
{0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */},
{AArch64::CMEQv8i8, AArch64::CMHIv8i8, AArch64::CMHSv8i8,
AArch64::CMHIv8i8, AArch64::CMHSv8i8, AArch64::CMGTv8i8,
AArch64::CMGEv8i8, AArch64::CMGTv8i8, AArch64::CMGEv8i8},
{AArch64::CMEQv16i8, AArch64::CMHIv16i8, AArch64::CMHSv16i8,
AArch64::CMHIv16i8, AArch64::CMHSv16i8, AArch64::CMGTv16i8,
AArch64::CMGEv16i8, AArch64::CMGTv16i8, AArch64::CMGEv16i8}
},
{
{0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */},
{AArch64::CMEQv4i16, AArch64::CMHIv4i16, AArch64::CMHSv4i16,
AArch64::CMHIv4i16, AArch64::CMHSv4i16, AArch64::CMGTv4i16,
AArch64::CMGEv4i16, AArch64::CMGTv4i16, AArch64::CMGEv4i16},
{AArch64::CMEQv8i16, AArch64::CMHIv8i16, AArch64::CMHSv8i16,
AArch64::CMHIv8i16, AArch64::CMHSv8i16, AArch64::CMGTv8i16,
AArch64::CMGEv8i16, AArch64::CMGTv8i16, AArch64::CMGEv8i16},
{0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */}
},
{
{AArch64::CMEQv2i32, AArch64::CMHIv2i32, AArch64::CMHSv2i32,
AArch64::CMHIv2i32, AArch64::CMHSv2i32, AArch64::CMGTv2i32,
AArch64::CMGEv2i32, AArch64::CMGTv2i32, AArch64::CMGEv2i32},
{AArch64::CMEQv4i32, AArch64::CMHIv4i32, AArch64::CMHSv4i32,
AArch64::CMHIv4i32, AArch64::CMHSv4i32, AArch64::CMGTv4i32,
AArch64::CMGEv4i32, AArch64::CMGTv4i32, AArch64::CMGEv4i32},
{0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */},
{0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */}
},
{
{AArch64::CMEQv2i64, AArch64::CMHIv2i64, AArch64::CMHSv2i64,
AArch64::CMHIv2i64, AArch64::CMHSv2i64, AArch64::CMGTv2i64,
AArch64::CMGEv2i64, AArch64::CMGTv2i64, AArch64::CMGEv2i64},
{0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */},
{0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */},
{0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */, 0 /* invalid */, 0 /* invalid */, 0 /* invalid */,
0 /* invalid */}
},
};
unsigned EltIdx = Log2_32(SrcEltSize / 8);
unsigned NumEltsIdx = Log2_32(NumElts / 2);
unsigned Opc = OpcTable[EltIdx][NumEltsIdx][PredIdx];
if (!Opc) {
LLVM_DEBUG(dbgs() << "Could not map G_ICMP to cmp opcode");
return false;
}
const RegisterBank &VecRB = *RBI.getRegBank(SrcReg, MRI, TRI);
const TargetRegisterClass *SrcRC =
getRegClassForTypeOnBank(SrcTy, VecRB, RBI, true);
if (!SrcRC) {
LLVM_DEBUG(dbgs() << "Could not determine source register class.\n");
return false;
}
unsigned NotOpc = Pred == ICmpInst::ICMP_NE ? AArch64::NOTv8i8 : 0;
if (SrcTy.getSizeInBits() == 128)
NotOpc = NotOpc ? AArch64::NOTv16i8 : 0;
if (SwapOperands)
std::swap(SrcReg, Src2Reg);
MachineIRBuilder MIB(I);
auto Cmp = MIB.buildInstr(Opc, {SrcRC}, {SrcReg, Src2Reg});
constrainSelectedInstRegOperands(*Cmp, TII, TRI, RBI);
// Invert if we had a 'ne' cc.
if (NotOpc) {
Cmp = MIB.buildInstr(NotOpc, {DstReg}, {Cmp});
constrainSelectedInstRegOperands(*Cmp, TII, TRI, RBI);
} else {
MIB.buildCopy(DstReg, Cmp.getReg(0));
}
RBI.constrainGenericRegister(DstReg, *SrcRC, MRI);
I.eraseFromParent();
return true;
}
MachineInstr *AArch64InstructionSelector::emitScalarToVector(
unsigned EltSize, const TargetRegisterClass *DstRC, Register Scalar,
MachineIRBuilder &MIRBuilder) const {
auto Undef = MIRBuilder.buildInstr(TargetOpcode::IMPLICIT_DEF, {DstRC}, {});
auto BuildFn = [&](unsigned SubregIndex) {
auto Ins =
MIRBuilder
.buildInstr(TargetOpcode::INSERT_SUBREG, {DstRC}, {Undef, Scalar})
.addImm(SubregIndex);
constrainSelectedInstRegOperands(*Undef, TII, TRI, RBI);
constrainSelectedInstRegOperands(*Ins, TII, TRI, RBI);
return &*Ins;
};
switch (EltSize) {
case 16:
return BuildFn(AArch64::hsub);
case 32:
return BuildFn(AArch64::ssub);
case 64:
return BuildFn(AArch64::dsub);
default:
return nullptr;
}
}
bool AArch64InstructionSelector::selectMergeValues(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_MERGE_VALUES && "unexpected opcode");
const LLT DstTy = MRI.getType(I.getOperand(0).getReg());
const LLT SrcTy = MRI.getType(I.getOperand(1).getReg());
assert(!DstTy.isVector() && !SrcTy.isVector() && "invalid merge operation");
const RegisterBank &RB = *RBI.getRegBank(I.getOperand(1).getReg(), MRI, TRI);
if (I.getNumOperands() != 3)
return false;
// Merging 2 s64s into an s128.
if (DstTy == LLT::scalar(128)) {
if (SrcTy.getSizeInBits() != 64)
return false;
MachineIRBuilder MIB(I);
Register DstReg = I.getOperand(0).getReg();
Register Src1Reg = I.getOperand(1).getReg();
Register Src2Reg = I.getOperand(2).getReg();
auto Tmp = MIB.buildInstr(TargetOpcode::IMPLICIT_DEF, {DstTy}, {});
MachineInstr *InsMI =
emitLaneInsert(None, Tmp.getReg(0), Src1Reg, /* LaneIdx */ 0, RB, MIB);
if (!InsMI)
return false;
MachineInstr *Ins2MI = emitLaneInsert(DstReg, InsMI->getOperand(0).getReg(),
Src2Reg, /* LaneIdx */ 1, RB, MIB);
if (!Ins2MI)
return false;
constrainSelectedInstRegOperands(*InsMI, TII, TRI, RBI);
constrainSelectedInstRegOperands(*Ins2MI, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
if (RB.getID() != AArch64::GPRRegBankID)
return false;
if (DstTy.getSizeInBits() != 64 || SrcTy.getSizeInBits() != 32)
return false;
auto *DstRC = &AArch64::GPR64RegClass;
Register SubToRegDef = MRI.createVirtualRegister(DstRC);
MachineInstr &SubRegMI = *BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(TargetOpcode::SUBREG_TO_REG))
.addDef(SubToRegDef)
.addImm(0)
.addUse(I.getOperand(1).getReg())
.addImm(AArch64::sub_32);
Register SubToRegDef2 = MRI.createVirtualRegister(DstRC);
// Need to anyext the second scalar before we can use bfm
MachineInstr &SubRegMI2 = *BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(TargetOpcode::SUBREG_TO_REG))
.addDef(SubToRegDef2)
.addImm(0)
.addUse(I.getOperand(2).getReg())
.addImm(AArch64::sub_32);
MachineInstr &BFM =
*BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(AArch64::BFMXri))
.addDef(I.getOperand(0).getReg())
.addUse(SubToRegDef)
.addUse(SubToRegDef2)
.addImm(32)
.addImm(31);
constrainSelectedInstRegOperands(SubRegMI, TII, TRI, RBI);
constrainSelectedInstRegOperands(SubRegMI2, TII, TRI, RBI);
constrainSelectedInstRegOperands(BFM, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
static bool getLaneCopyOpcode(unsigned &CopyOpc, unsigned &ExtractSubReg,
const unsigned EltSize) {
// Choose a lane copy opcode and subregister based off of the size of the
// vector's elements.
switch (EltSize) {
case 16:
CopyOpc = AArch64::CPYi16;
ExtractSubReg = AArch64::hsub;
break;
case 32:
CopyOpc = AArch64::CPYi32;
ExtractSubReg = AArch64::ssub;
break;
case 64:
CopyOpc = AArch64::CPYi64;
ExtractSubReg = AArch64::dsub;
break;
default:
// Unknown size, bail out.
LLVM_DEBUG(dbgs() << "Elt size '" << EltSize << "' unsupported.\n");
return false;
}
return true;
}
MachineInstr *AArch64InstructionSelector::emitExtractVectorElt(
Optional<Register> DstReg, const RegisterBank &DstRB, LLT ScalarTy,
Register VecReg, unsigned LaneIdx, MachineIRBuilder &MIRBuilder) const {
MachineRegisterInfo &MRI = *MIRBuilder.getMRI();
unsigned CopyOpc = 0;
unsigned ExtractSubReg = 0;
if (!getLaneCopyOpcode(CopyOpc, ExtractSubReg, ScalarTy.getSizeInBits())) {
LLVM_DEBUG(
dbgs() << "Couldn't determine lane copy opcode for instruction.\n");
return nullptr;
}
const TargetRegisterClass *DstRC =
getRegClassForTypeOnBank(ScalarTy, DstRB, RBI, true);
if (!DstRC) {
LLVM_DEBUG(dbgs() << "Could not determine destination register class.\n");
return nullptr;
}
const RegisterBank &VecRB = *RBI.getRegBank(VecReg, MRI, TRI);
const LLT &VecTy = MRI.getType(VecReg);
const TargetRegisterClass *VecRC =
getRegClassForTypeOnBank(VecTy, VecRB, RBI, true);
if (!VecRC) {
LLVM_DEBUG(dbgs() << "Could not determine source register class.\n");
return nullptr;
}
// The register that we're going to copy into.
Register InsertReg = VecReg;
if (!DstReg)
DstReg = MRI.createVirtualRegister(DstRC);
// If the lane index is 0, we just use a subregister COPY.
if (LaneIdx == 0) {
auto Copy = MIRBuilder.buildInstr(TargetOpcode::COPY, {*DstReg}, {})
.addReg(VecReg, 0, ExtractSubReg);
RBI.constrainGenericRegister(*DstReg, *DstRC, MRI);
return &*Copy;
}
// Lane copies require 128-bit wide registers. If we're dealing with an
// unpacked vector, then we need to move up to that width. Insert an implicit
// def and a subregister insert to get us there.
if (VecTy.getSizeInBits() != 128) {
MachineInstr *ScalarToVector = emitScalarToVector(
VecTy.getSizeInBits(), &AArch64::FPR128RegClass, VecReg, MIRBuilder);
if (!ScalarToVector)
return nullptr;
InsertReg = ScalarToVector->getOperand(0).getReg();
}
MachineInstr *LaneCopyMI =
MIRBuilder.buildInstr(CopyOpc, {*DstReg}, {InsertReg}).addImm(LaneIdx);
constrainSelectedInstRegOperands(*LaneCopyMI, TII, TRI, RBI);
// Make sure that we actually constrain the initial copy.
RBI.constrainGenericRegister(*DstReg, *DstRC, MRI);
return LaneCopyMI;
}
bool AArch64InstructionSelector::selectExtractElt(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_EXTRACT_VECTOR_ELT &&
"unexpected opcode!");
Register DstReg = I.getOperand(0).getReg();
const LLT NarrowTy = MRI.getType(DstReg);
const Register SrcReg = I.getOperand(1).getReg();
const LLT WideTy = MRI.getType(SrcReg);
(void)WideTy;
assert(WideTy.getSizeInBits() >= NarrowTy.getSizeInBits() &&
"source register size too small!");
assert(NarrowTy.isScalar() && "cannot extract vector into vector!");
// Need the lane index to determine the correct copy opcode.
MachineOperand &LaneIdxOp = I.getOperand(2);
assert(LaneIdxOp.isReg() && "Lane index operand was not a register?");
if (RBI.getRegBank(DstReg, MRI, TRI)->getID() != AArch64::FPRRegBankID) {
LLVM_DEBUG(dbgs() << "Cannot extract into GPR.\n");
return false;
}
// Find the index to extract from.
auto VRegAndVal = getConstantVRegValWithLookThrough(LaneIdxOp.getReg(), MRI);
if (!VRegAndVal)
return false;
unsigned LaneIdx = VRegAndVal->Value;
MachineIRBuilder MIRBuilder(I);
const RegisterBank &DstRB = *RBI.getRegBank(DstReg, MRI, TRI);
MachineInstr *Extract = emitExtractVectorElt(DstReg, DstRB, NarrowTy, SrcReg,
LaneIdx, MIRBuilder);
if (!Extract)
return false;
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectSplitVectorUnmerge(
MachineInstr &I, MachineRegisterInfo &MRI) const {
unsigned NumElts = I.getNumOperands() - 1;
Register SrcReg = I.getOperand(NumElts).getReg();
const LLT NarrowTy = MRI.getType(I.getOperand(0).getReg());
const LLT SrcTy = MRI.getType(SrcReg);
assert(NarrowTy.isVector() && "Expected an unmerge into vectors");
if (SrcTy.getSizeInBits() > 128) {
LLVM_DEBUG(dbgs() << "Unexpected vector type for vec split unmerge");
return false;
}
MachineIRBuilder MIB(I);
// We implement a split vector operation by treating the sub-vectors as
// scalars and extracting them.
const RegisterBank &DstRB =
*RBI.getRegBank(I.getOperand(0).getReg(), MRI, TRI);
for (unsigned OpIdx = 0; OpIdx < NumElts; ++OpIdx) {
Register Dst = I.getOperand(OpIdx).getReg();
MachineInstr *Extract =
emitExtractVectorElt(Dst, DstRB, NarrowTy, SrcReg, OpIdx, MIB);
if (!Extract)
return false;
}
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectUnmergeValues(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_UNMERGE_VALUES &&
"unexpected opcode");
// TODO: Handle unmerging into GPRs and from scalars to scalars.
if (RBI.getRegBank(I.getOperand(0).getReg(), MRI, TRI)->getID() !=
AArch64::FPRRegBankID ||
RBI.getRegBank(I.getOperand(1).getReg(), MRI, TRI)->getID() !=
AArch64::FPRRegBankID) {
LLVM_DEBUG(dbgs() << "Unmerging vector-to-gpr and scalar-to-scalar "
"currently unsupported.\n");
return false;
}
// The last operand is the vector source register, and every other operand is
// a register to unpack into.
unsigned NumElts = I.getNumOperands() - 1;
Register SrcReg = I.getOperand(NumElts).getReg();
const LLT NarrowTy = MRI.getType(I.getOperand(0).getReg());
const LLT WideTy = MRI.getType(SrcReg);
(void)WideTy;
assert((WideTy.isVector() || WideTy.getSizeInBits() == 128) &&
"can only unmerge from vector or s128 types!");
assert(WideTy.getSizeInBits() > NarrowTy.getSizeInBits() &&
"source register size too small!");
if (!NarrowTy.isScalar())
return selectSplitVectorUnmerge(I, MRI);
MachineIRBuilder MIB(I);
// Choose a lane copy opcode and subregister based off of the size of the
// vector's elements.
unsigned CopyOpc = 0;
unsigned ExtractSubReg = 0;
if (!getLaneCopyOpcode(CopyOpc, ExtractSubReg, NarrowTy.getSizeInBits()))
return false;
// Set up for the lane copies.
MachineBasicBlock &MBB = *I.getParent();
// Stores the registers we'll be copying from.
SmallVector<Register, 4> InsertRegs;
// We'll use the first register twice, so we only need NumElts-1 registers.
unsigned NumInsertRegs = NumElts - 1;
// If our elements fit into exactly 128 bits, then we can copy from the source
// directly. Otherwise, we need to do a bit of setup with some subregister
// inserts.
if (NarrowTy.getSizeInBits() * NumElts == 128) {
InsertRegs = SmallVector<Register, 4>(NumInsertRegs, SrcReg);
} else {
// No. We have to perform subregister inserts. For each insert, create an
// implicit def and a subregister insert, and save the register we create.
for (unsigned Idx = 0; Idx < NumInsertRegs; ++Idx) {
Register ImpDefReg = MRI.createVirtualRegister(&AArch64::FPR128RegClass);
MachineInstr &ImpDefMI =
*BuildMI(MBB, I, I.getDebugLoc(), TII.get(TargetOpcode::IMPLICIT_DEF),
ImpDefReg);
// Now, create the subregister insert from SrcReg.
Register InsertReg = MRI.createVirtualRegister(&AArch64::FPR128RegClass);
MachineInstr &InsMI =
*BuildMI(MBB, I, I.getDebugLoc(),
TII.get(TargetOpcode::INSERT_SUBREG), InsertReg)
.addUse(ImpDefReg)
.addUse(SrcReg)
.addImm(AArch64::dsub);
constrainSelectedInstRegOperands(ImpDefMI, TII, TRI, RBI);
constrainSelectedInstRegOperands(InsMI, TII, TRI, RBI);
// Save the register so that we can copy from it after.
InsertRegs.push_back(InsertReg);
}
}
// Now that we've created any necessary subregister inserts, we can
// create the copies.
//
// Perform the first copy separately as a subregister copy.
Register CopyTo = I.getOperand(0).getReg();
auto FirstCopy = MIB.buildInstr(TargetOpcode::COPY, {CopyTo}, {})
.addReg(InsertRegs[0], 0, ExtractSubReg);
constrainSelectedInstRegOperands(*FirstCopy, TII, TRI, RBI);
// Now, perform the remaining copies as vector lane copies.
unsigned LaneIdx = 1;
for (Register InsReg : InsertRegs) {
Register CopyTo = I.getOperand(LaneIdx).getReg();
MachineInstr &CopyInst =
*BuildMI(MBB, I, I.getDebugLoc(), TII.get(CopyOpc), CopyTo)
.addUse(InsReg)
.addImm(LaneIdx);
constrainSelectedInstRegOperands(CopyInst, TII, TRI, RBI);
++LaneIdx;
}
// Separately constrain the first copy's destination. Because of the
// limitation in constrainOperandRegClass, we can't guarantee that this will
// actually be constrained. So, do it ourselves using the second operand.
const TargetRegisterClass *RC =
MRI.getRegClassOrNull(I.getOperand(1).getReg());
if (!RC) {
LLVM_DEBUG(dbgs() << "Couldn't constrain copy destination.\n");
return false;
}
RBI.constrainGenericRegister(CopyTo, *RC, MRI);
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectConcatVectors(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_CONCAT_VECTORS &&
"Unexpected opcode");
Register Dst = I.getOperand(0).getReg();
Register Op1 = I.getOperand(1).getReg();
Register Op2 = I.getOperand(2).getReg();
MachineIRBuilder MIRBuilder(I);
MachineInstr *ConcatMI = emitVectorConcat(Dst, Op1, Op2, MIRBuilder);
if (!ConcatMI)
return false;
I.eraseFromParent();
return true;
}
unsigned
AArch64InstructionSelector::emitConstantPoolEntry(Constant *CPVal,
MachineFunction &MF) const {
Type *CPTy = CPVal->getType();
unsigned Align = MF.getDataLayout().getPrefTypeAlignment(CPTy);
if (Align == 0)
Align = MF.getDataLayout().getTypeAllocSize(CPTy);
MachineConstantPool *MCP = MF.getConstantPool();
return MCP->getConstantPoolIndex(CPVal, Align);
}
MachineInstr *AArch64InstructionSelector::emitLoadFromConstantPool(
Constant *CPVal, MachineIRBuilder &MIRBuilder) const {
unsigned CPIdx = emitConstantPoolEntry(CPVal, MIRBuilder.getMF());
auto Adrp =
MIRBuilder.buildInstr(AArch64::ADRP, {&AArch64::GPR64RegClass}, {})
.addConstantPoolIndex(CPIdx, 0, AArch64II::MO_PAGE);
MachineInstr *LoadMI = nullptr;
switch (MIRBuilder.getDataLayout().getTypeStoreSize(CPVal->getType())) {
case 16:
LoadMI =
&*MIRBuilder
.buildInstr(AArch64::LDRQui, {&AArch64::FPR128RegClass}, {Adrp})
.addConstantPoolIndex(CPIdx, 0,
AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
break;
case 8:
LoadMI = &*MIRBuilder
.buildInstr(AArch64::LDRDui, {&AArch64::FPR64RegClass}, {Adrp})
.addConstantPoolIndex(
CPIdx, 0, AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
break;
default:
LLVM_DEBUG(dbgs() << "Could not load from constant pool of type "
<< *CPVal->getType());
return nullptr;
}
constrainSelectedInstRegOperands(*Adrp, TII, TRI, RBI);
constrainSelectedInstRegOperands(*LoadMI, TII, TRI, RBI);
return LoadMI;
}
/// Return an <Opcode, SubregIndex> pair to do an vector elt insert of a given
/// size and RB.
static std::pair<unsigned, unsigned>
getInsertVecEltOpInfo(const RegisterBank &RB, unsigned EltSize) {
unsigned Opc, SubregIdx;
if (RB.getID() == AArch64::GPRRegBankID) {
if (EltSize == 32) {
Opc = AArch64::INSvi32gpr;
SubregIdx = AArch64::ssub;
} else if (EltSize == 64) {
Opc = AArch64::INSvi64gpr;
SubregIdx = AArch64::dsub;
} else {
llvm_unreachable("invalid elt size!");
}
} else {
if (EltSize == 8) {
Opc = AArch64::INSvi8lane;
SubregIdx = AArch64::bsub;
} else if (EltSize == 16) {
Opc = AArch64::INSvi16lane;
SubregIdx = AArch64::hsub;
} else if (EltSize == 32) {
Opc = AArch64::INSvi32lane;
SubregIdx = AArch64::ssub;
} else if (EltSize == 64) {
Opc = AArch64::INSvi64lane;
SubregIdx = AArch64::dsub;
} else {
llvm_unreachable("invalid elt size!");
}
}
return std::make_pair(Opc, SubregIdx);
}
MachineInstr *
AArch64InstructionSelector::emitADD(Register DefReg, MachineOperand &LHS,
MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const {
assert(LHS.isReg() && RHS.isReg() && "Expected LHS and RHS to be registers!");
MachineRegisterInfo &MRI = MIRBuilder.getMF().getRegInfo();
static const unsigned OpcTable[2][2]{{AArch64::ADDXrr, AArch64::ADDXri},
{AArch64::ADDWrr, AArch64::ADDWri}};
bool Is32Bit = MRI.getType(LHS.getReg()).getSizeInBits() == 32;
auto ImmFns = selectArithImmed(RHS);
unsigned Opc = OpcTable[Is32Bit][ImmFns.hasValue()];
auto AddMI = MIRBuilder.buildInstr(Opc, {DefReg}, {LHS.getReg()});
// If we matched a valid constant immediate, add those operands.
if (ImmFns) {
for (auto &RenderFn : *ImmFns)
RenderFn(AddMI);
} else {
AddMI.addUse(RHS.getReg());
}
constrainSelectedInstRegOperands(*AddMI, TII, TRI, RBI);
return &*AddMI;
}
MachineInstr *
AArch64InstructionSelector::emitCMN(MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const {
assert(LHS.isReg() && RHS.isReg() && "Expected LHS and RHS to be registers!");
MachineRegisterInfo &MRI = MIRBuilder.getMF().getRegInfo();
static const unsigned OpcTable[2][2]{{AArch64::ADDSXrr, AArch64::ADDSXri},
{AArch64::ADDSWrr, AArch64::ADDSWri}};
bool Is32Bit = (MRI.getType(LHS.getReg()).getSizeInBits() == 32);
auto ImmFns = selectArithImmed(RHS);
unsigned Opc = OpcTable[Is32Bit][ImmFns.hasValue()];
Register ZReg = Is32Bit ? AArch64::WZR : AArch64::XZR;
auto CmpMI = MIRBuilder.buildInstr(Opc, {ZReg}, {LHS.getReg()});
// If we matched a valid constant immediate, add those operands.
if (ImmFns) {
for (auto &RenderFn : *ImmFns)
RenderFn(CmpMI);
} else {
CmpMI.addUse(RHS.getReg());
}
constrainSelectedInstRegOperands(*CmpMI, TII, TRI, RBI);
return &*CmpMI;
}
MachineInstr *
AArch64InstructionSelector::emitTST(const Register &LHS, const Register &RHS,
MachineIRBuilder &MIRBuilder) const {
MachineRegisterInfo &MRI = MIRBuilder.getMF().getRegInfo();
unsigned RegSize = MRI.getType(LHS).getSizeInBits();
bool Is32Bit = (RegSize == 32);
static const unsigned OpcTable[2][2]{{AArch64::ANDSXrr, AArch64::ANDSXri},
{AArch64::ANDSWrr, AArch64::ANDSWri}};
Register ZReg = Is32Bit ? AArch64::WZR : AArch64::XZR;
// We might be able to fold in an immediate into the TST. We need to make sure
// it's a logical immediate though, since ANDS requires that.
auto ValAndVReg = getConstantVRegValWithLookThrough(RHS, MRI);
bool IsImmForm = ValAndVReg.hasValue() &&
AArch64_AM::isLogicalImmediate(ValAndVReg->Value, RegSize);
unsigned Opc = OpcTable[Is32Bit][IsImmForm];
auto TstMI = MIRBuilder.buildInstr(Opc, {ZReg}, {LHS});
if (IsImmForm)
TstMI.addImm(
AArch64_AM::encodeLogicalImmediate(ValAndVReg->Value, RegSize));
else
TstMI.addUse(RHS);
constrainSelectedInstRegOperands(*TstMI, TII, TRI, RBI);
return &*TstMI;
}
MachineInstr *AArch64InstructionSelector::emitIntegerCompare(
MachineOperand &LHS, MachineOperand &RHS, MachineOperand &Predicate,
MachineIRBuilder &MIRBuilder) const {
assert(LHS.isReg() && RHS.isReg() && "Expected LHS and RHS to be registers!");
MachineRegisterInfo &MRI = MIRBuilder.getMF().getRegInfo();
// Fold the compare if possible.
MachineInstr *FoldCmp =
tryFoldIntegerCompare(LHS, RHS, Predicate, MIRBuilder);
if (FoldCmp)
return FoldCmp;
// Can't fold into a CMN. Just emit a normal compare.
unsigned CmpOpc = 0;
Register ZReg;
LLT CmpTy = MRI.getType(LHS.getReg());
assert((CmpTy.isScalar() || CmpTy.isPointer()) &&
"Expected scalar or pointer");
if (CmpTy == LLT::scalar(32)) {
CmpOpc = AArch64::SUBSWrr;
ZReg = AArch64::WZR;
} else if (CmpTy == LLT::scalar(64) || CmpTy.isPointer()) {
CmpOpc = AArch64::SUBSXrr;
ZReg = AArch64::XZR;
} else {
return nullptr;
}
// Try to match immediate forms.
auto ImmFns = selectArithImmed(RHS);
if (ImmFns)
CmpOpc = CmpOpc == AArch64::SUBSWrr ? AArch64::SUBSWri : AArch64::SUBSXri;
auto CmpMI = MIRBuilder.buildInstr(CmpOpc).addDef(ZReg).addUse(LHS.getReg());
// If we matched a valid constant immediate, add those operands.
if (ImmFns) {
for (auto &RenderFn : *ImmFns)
RenderFn(CmpMI);
} else {
CmpMI.addUse(RHS.getReg());
}
// Make sure that we can constrain the compare that we emitted.
constrainSelectedInstRegOperands(*CmpMI, TII, TRI, RBI);
return &*CmpMI;
}
MachineInstr *AArch64InstructionSelector::emitVectorConcat(
Optional<Register> Dst, Register Op1, Register Op2,
MachineIRBuilder &MIRBuilder) const {
// We implement a vector concat by:
// 1. Use scalar_to_vector to insert the lower vector into the larger dest
// 2. Insert the upper vector into the destination's upper element
// TODO: some of this code is common with G_BUILD_VECTOR handling.
MachineRegisterInfo &MRI = MIRBuilder.getMF().getRegInfo();
const LLT Op1Ty = MRI.getType(Op1);
const LLT Op2Ty = MRI.getType(Op2);
if (Op1Ty != Op2Ty) {
LLVM_DEBUG(dbgs() << "Could not do vector concat of differing vector tys");
return nullptr;
}
assert(Op1Ty.isVector() && "Expected a vector for vector concat");
if (Op1Ty.getSizeInBits() >= 128) {
LLVM_DEBUG(dbgs() << "Vector concat not supported for full size vectors");
return nullptr;
}
// At the moment we just support 64 bit vector concats.
if (Op1Ty.getSizeInBits() != 64) {
LLVM_DEBUG(dbgs() << "Vector concat supported for 64b vectors");
return nullptr;
}
const LLT ScalarTy = LLT::scalar(Op1Ty.getSizeInBits());
const RegisterBank &FPRBank = *RBI.getRegBank(Op1, MRI, TRI);
const TargetRegisterClass *DstRC =
getMinClassForRegBank(FPRBank, Op1Ty.getSizeInBits() * 2);
MachineInstr *WidenedOp1 =
emitScalarToVector(ScalarTy.getSizeInBits(), DstRC, Op1, MIRBuilder);
MachineInstr *WidenedOp2 =
emitScalarToVector(ScalarTy.getSizeInBits(), DstRC, Op2, MIRBuilder);
if (!WidenedOp1 || !WidenedOp2) {
LLVM_DEBUG(dbgs() << "Could not emit a vector from scalar value");
return nullptr;
}
// Now do the insert of the upper element.
unsigned InsertOpc, InsSubRegIdx;
std::tie(InsertOpc, InsSubRegIdx) =
getInsertVecEltOpInfo(FPRBank, ScalarTy.getSizeInBits());
if (!Dst)
Dst = MRI.createVirtualRegister(DstRC);
auto InsElt =
MIRBuilder
.buildInstr(InsertOpc, {*Dst}, {WidenedOp1->getOperand(0).getReg()})
.addImm(1) /* Lane index */
.addUse(WidenedOp2->getOperand(0).getReg())
.addImm(0);
constrainSelectedInstRegOperands(*InsElt, TII, TRI, RBI);
return &*InsElt;
}
MachineInstr *AArch64InstructionSelector::emitFMovForFConstant(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_FCONSTANT &&
"Expected a G_FCONSTANT!");
MachineOperand &ImmOp = I.getOperand(1);
unsigned DefSize = MRI.getType(I.getOperand(0).getReg()).getSizeInBits();
// Only handle 32 and 64 bit defs for now.
if (DefSize != 32 && DefSize != 64)
return nullptr;
// Don't handle null values using FMOV.
if (ImmOp.getFPImm()->isNullValue())
return nullptr;
// Get the immediate representation for the FMOV.
const APFloat &ImmValAPF = ImmOp.getFPImm()->getValueAPF();
int Imm = DefSize == 32 ? AArch64_AM::getFP32Imm(ImmValAPF)
: AArch64_AM::getFP64Imm(ImmValAPF);
// If this is -1, it means the immediate can't be represented as the requested
// floating point value. Bail.
if (Imm == -1)
return nullptr;
// Update MI to represent the new FMOV instruction, constrain it, and return.
ImmOp.ChangeToImmediate(Imm);
unsigned MovOpc = DefSize == 32 ? AArch64::FMOVSi : AArch64::FMOVDi;
I.setDesc(TII.get(MovOpc));
constrainSelectedInstRegOperands(I, TII, TRI, RBI);
return &I;
}
MachineInstr *
AArch64InstructionSelector::emitCSetForICMP(Register DefReg, unsigned Pred,
MachineIRBuilder &MIRBuilder) const {
// CSINC increments the result when the predicate is false. Invert it.
const AArch64CC::CondCode InvCC = changeICMPPredToAArch64CC(
CmpInst::getInversePredicate((CmpInst::Predicate)Pred));
auto I =
MIRBuilder
.buildInstr(AArch64::CSINCWr, {DefReg}, {Register(AArch64::WZR), Register(AArch64::WZR)})
.addImm(InvCC);
constrainSelectedInstRegOperands(*I, TII, TRI, RBI);
return &*I;
}
bool AArch64InstructionSelector::tryOptSelect(MachineInstr &I) const {
MachineIRBuilder MIB(I);
MachineRegisterInfo &MRI = *MIB.getMRI();
const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
// We want to recognize this pattern:
//
// $z = G_FCMP pred, $x, $y
// ...
// $w = G_SELECT $z, $a, $b
//
// Where the value of $z is *only* ever used by the G_SELECT (possibly with
// some copies/truncs in between.)
//
// If we see this, then we can emit something like this:
//
// fcmp $x, $y
// fcsel $w, $a, $b, pred
//
// Rather than emitting both of the rather long sequences in the standard
// G_FCMP/G_SELECT select methods.
// First, check if the condition is defined by a compare.
MachineInstr *CondDef = MRI.getVRegDef(I.getOperand(1).getReg());
while (CondDef) {
// We can only fold if all of the defs have one use.
if (!MRI.hasOneUse(CondDef->getOperand(0).getReg()))
return false;
// We can skip over G_TRUNC since the condition is 1-bit.
// Truncating/extending can have no impact on the value.
unsigned Opc = CondDef->getOpcode();
if (Opc != TargetOpcode::COPY && Opc != TargetOpcode::G_TRUNC)
break;
// Can't see past copies from physregs.
if (Opc == TargetOpcode::COPY &&
Register::isPhysicalRegister(CondDef->getOperand(1).getReg()))
return false;
CondDef = MRI.getVRegDef(CondDef->getOperand(1).getReg());
}
// Is the condition defined by a compare?
if (!CondDef)
return false;
unsigned CondOpc = CondDef->getOpcode();
if (CondOpc != TargetOpcode::G_ICMP && CondOpc != TargetOpcode::G_FCMP)
return false;
AArch64CC::CondCode CondCode;
if (CondOpc == TargetOpcode::G_ICMP) {
CondCode = changeICMPPredToAArch64CC(
(CmpInst::Predicate)CondDef->getOperand(1).getPredicate());
if (!emitIntegerCompare(CondDef->getOperand(2), CondDef->getOperand(3),
CondDef->getOperand(1), MIB)) {
LLVM_DEBUG(dbgs() << "Couldn't emit compare for select!\n");
return false;
}
} else {
// Get the condition code for the select.
AArch64CC::CondCode CondCode2;
changeFCMPPredToAArch64CC(
(CmpInst::Predicate)CondDef->getOperand(1).getPredicate(), CondCode,
CondCode2);
// changeFCMPPredToAArch64CC sets CondCode2 to AL when we require two
// instructions to emit the comparison.
// TODO: Handle FCMP_UEQ and FCMP_ONE. After that, this check will be
// unnecessary.
if (CondCode2 != AArch64CC::AL)
return false;
// Make sure we'll be able to select the compare.
unsigned CmpOpc = selectFCMPOpc(*CondDef, MRI);
if (!CmpOpc)
return false;
// Emit a new compare.
auto Cmp = MIB.buildInstr(CmpOpc, {}, {CondDef->getOperand(2).getReg()});
if (CmpOpc != AArch64::FCMPSri && CmpOpc != AArch64::FCMPDri)
Cmp.addUse(CondDef->getOperand(3).getReg());
constrainSelectedInstRegOperands(*Cmp, TII, TRI, RBI);
}
// Emit the select.
unsigned CSelOpc = selectSelectOpc(I, MRI, RBI);
auto CSel =
MIB.buildInstr(CSelOpc, {I.getOperand(0).getReg()},
{I.getOperand(2).getReg(), I.getOperand(3).getReg()})
.addImm(CondCode);
constrainSelectedInstRegOperands(*CSel, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
MachineInstr *AArch64InstructionSelector::tryFoldIntegerCompare(
MachineOperand &LHS, MachineOperand &RHS, MachineOperand &Predicate,
MachineIRBuilder &MIRBuilder) const {
assert(LHS.isReg() && RHS.isReg() && Predicate.isPredicate() &&
"Unexpected MachineOperand");
MachineRegisterInfo &MRI = *MIRBuilder.getMRI();
// We want to find this sort of thing:
// x = G_SUB 0, y
// G_ICMP z, x
//
// In this case, we can fold the G_SUB into the G_ICMP using a CMN instead.
// e.g:
//
// cmn z, y
// Helper lambda to detect the subtract followed by the compare.
// Takes in the def of the LHS or RHS, and checks if it's a subtract from 0.
auto IsCMN = [&](MachineInstr *DefMI, const AArch64CC::CondCode &CC) {
if (!DefMI || DefMI->getOpcode() != TargetOpcode::G_SUB)
return false;
// Need to make sure NZCV is the same at the end of the transformation.
if (CC != AArch64CC::EQ && CC != AArch64CC::NE)
return false;
// We want to match against SUBs.
if (DefMI->getOpcode() != TargetOpcode::G_SUB)
return false;
// Make sure that we're getting
// x = G_SUB 0, y
auto ValAndVReg =
getConstantVRegValWithLookThrough(DefMI->getOperand(1).getReg(), MRI);
if (!ValAndVReg || ValAndVReg->Value != 0)
return false;
// This can safely be represented as a CMN.
return true;
};
// Check if the RHS or LHS of the G_ICMP is defined by a SUB
MachineInstr *LHSDef = getDefIgnoringCopies(LHS.getReg(), MRI);
MachineInstr *RHSDef = getDefIgnoringCopies(RHS.getReg(), MRI);
CmpInst::Predicate P = (CmpInst::Predicate)Predicate.getPredicate();
const AArch64CC::CondCode CC = changeICMPPredToAArch64CC(P);
// Given this:
//
// x = G_SUB 0, y
// G_ICMP x, z
//
// Produce this:
//
// cmn y, z
if (IsCMN(LHSDef, CC))
return emitCMN(LHSDef->getOperand(2), RHS, MIRBuilder);
// Same idea here, but with the RHS of the compare instead:
//
// Given this:
//
// x = G_SUB 0, y
// G_ICMP z, x
//
// Produce this:
//
// cmn z, y
if (IsCMN(RHSDef, CC))
return emitCMN(LHS, RHSDef->getOperand(2), MIRBuilder);
// Given this:
//
// z = G_AND x, y
// G_ICMP z, 0
//
// Produce this if the compare is signed:
//
// tst x, y
if (!isUnsignedICMPPred(P) && LHSDef &&
LHSDef->getOpcode() == TargetOpcode::G_AND) {
// Make sure that the RHS is 0.
auto ValAndVReg = getConstantVRegValWithLookThrough(RHS.getReg(), MRI);
if (!ValAndVReg || ValAndVReg->Value != 0)
return nullptr;
return emitTST(LHSDef->getOperand(1).getReg(),
LHSDef->getOperand(2).getReg(), MIRBuilder);
}
return nullptr;
}
bool AArch64InstructionSelector::tryOptVectorDup(MachineInstr &I) const {
// Try to match a vector splat operation into a dup instruction.
// We're looking for this pattern:
// %scalar:gpr(s64) = COPY $x0
// %undef:fpr(<2 x s64>) = G_IMPLICIT_DEF
// %cst0:gpr(s32) = G_CONSTANT i32 0
// %zerovec:fpr(<2 x s32>) = G_BUILD_VECTOR %cst0(s32), %cst0(s32)
// %ins:fpr(<2 x s64>) = G_INSERT_VECTOR_ELT %undef, %scalar(s64), %cst0(s32)
// %splat:fpr(<2 x s64>) = G_SHUFFLE_VECTOR %ins(<2 x s64>), %undef,
// %zerovec(<2 x s32>)
//
// ...into:
// %splat = DUP %scalar
// We use the regbank of the scalar to determine which kind of dup to use.
MachineIRBuilder MIB(I);
MachineRegisterInfo &MRI = *MIB.getMRI();
const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
using namespace TargetOpcode;
using namespace MIPatternMatch;
// Begin matching the insert.
auto *InsMI =
getOpcodeDef(G_INSERT_VECTOR_ELT, I.getOperand(1).getReg(), MRI);
if (!InsMI)
return false;
// Match the undef vector operand.
auto *UndefMI =
getOpcodeDef(G_IMPLICIT_DEF, InsMI->getOperand(1).getReg(), MRI);
if (!UndefMI)
return false;
// Match the scalar being splatted.
Register ScalarReg = InsMI->getOperand(2).getReg();
const RegisterBank *ScalarRB = RBI.getRegBank(ScalarReg, MRI, TRI);
// Match the index constant 0.
int64_t Index = 0;
if (!mi_match(InsMI->getOperand(3).getReg(), MRI, m_ICst(Index)) || Index)
return false;
// The shuffle's second operand doesn't matter if the mask is all zero.
ArrayRef<int> Mask = I.getOperand(3).getShuffleMask();
if (!all_of(Mask, [](int Elem) { return Elem == 0; }))
return false;
// We're done, now find out what kind of splat we need.
LLT VecTy = MRI.getType(I.getOperand(0).getReg());
LLT EltTy = VecTy.getElementType();
if (EltTy.getSizeInBits() < 32) {
LLVM_DEBUG(dbgs() << "Could not optimize splat pattern < 32b elts yet");
return false;
}
bool IsFP = ScalarRB->getID() == AArch64::FPRRegBankID;
unsigned Opc = 0;
if (IsFP) {
switch (EltTy.getSizeInBits()) {
case 32:
if (VecTy.getNumElements() == 2) {
Opc = AArch64::DUPv2i32lane;
} else {
Opc = AArch64::DUPv4i32lane;
assert(VecTy.getNumElements() == 4);
}
break;
case 64:
assert(VecTy.getNumElements() == 2 && "Unexpected num elts");
Opc = AArch64::DUPv2i64lane;
break;
}
} else {
switch (EltTy.getSizeInBits()) {
case 32:
if (VecTy.getNumElements() == 2) {
Opc = AArch64::DUPv2i32gpr;
} else {
Opc = AArch64::DUPv4i32gpr;
assert(VecTy.getNumElements() == 4);
}
break;
case 64:
assert(VecTy.getNumElements() == 2 && "Unexpected num elts");
Opc = AArch64::DUPv2i64gpr;
break;
}
}
assert(Opc && "Did not compute an opcode for a dup");
// For FP splats, we need to widen the scalar reg via undef too.
if (IsFP) {
MachineInstr *Widen = emitScalarToVector(
EltTy.getSizeInBits(), &AArch64::FPR128RegClass, ScalarReg, MIB);
if (!Widen)
return false;
ScalarReg = Widen->getOperand(0).getReg();
}
auto Dup = MIB.buildInstr(Opc, {I.getOperand(0).getReg()}, {ScalarReg});
if (IsFP)
Dup.addImm(0);
constrainSelectedInstRegOperands(*Dup, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::tryOptVectorShuffle(MachineInstr &I) const {
if (TM.getOptLevel() == CodeGenOpt::None)
return false;
if (tryOptVectorDup(I))
return true;
return false;
}
bool AArch64InstructionSelector::selectShuffleVector(
MachineInstr &I, MachineRegisterInfo &MRI) const {
if (tryOptVectorShuffle(I))
return true;
const LLT DstTy = MRI.getType(I.getOperand(0).getReg());
Register Src1Reg = I.getOperand(1).getReg();
const LLT Src1Ty = MRI.getType(Src1Reg);
Register Src2Reg = I.getOperand(2).getReg();
const LLT Src2Ty = MRI.getType(Src2Reg);
ArrayRef<int> Mask = I.getOperand(3).getShuffleMask();
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
LLVMContext &Ctx = MF.getFunction().getContext();
// G_SHUFFLE_VECTOR is weird in that the source operands can be scalars, if
// it's originated from a <1 x T> type. Those should have been lowered into
// G_BUILD_VECTOR earlier.
if (!Src1Ty.isVector() || !Src2Ty.isVector()) {
LLVM_DEBUG(dbgs() << "Could not select a \"scalar\" G_SHUFFLE_VECTOR\n");
return false;
}
unsigned BytesPerElt = DstTy.getElementType().getSizeInBits() / 8;
SmallVector<Constant *, 64> CstIdxs;
for (int Val : Mask) {
// For now, any undef indexes we'll just assume to be 0. This should be
// optimized in future, e.g. to select DUP etc.
Val = Val < 0 ? 0 : Val;
for (unsigned Byte = 0; Byte < BytesPerElt; ++Byte) {
unsigned Offset = Byte + Val * BytesPerElt;
CstIdxs.emplace_back(ConstantInt::get(Type::getInt8Ty(Ctx), Offset));
}
}
MachineIRBuilder MIRBuilder(I);
// Use a constant pool to load the index vector for TBL.
Constant *CPVal = ConstantVector::get(CstIdxs);
MachineInstr *IndexLoad = emitLoadFromConstantPool(CPVal, MIRBuilder);
if (!IndexLoad) {
LLVM_DEBUG(dbgs() << "Could not load from a constant pool");
return false;
}
if (DstTy.getSizeInBits() != 128) {
assert(DstTy.getSizeInBits() == 64 && "Unexpected shuffle result ty");
// This case can be done with TBL1.
MachineInstr *Concat = emitVectorConcat(None, Src1Reg, Src2Reg, MIRBuilder);
if (!Concat) {
LLVM_DEBUG(dbgs() << "Could not do vector concat for tbl1");
return false;
}
// The constant pool load will be 64 bits, so need to convert to FPR128 reg.
IndexLoad =
emitScalarToVector(64, &AArch64::FPR128RegClass,
IndexLoad->getOperand(0).getReg(), MIRBuilder);
auto TBL1 = MIRBuilder.buildInstr(
AArch64::TBLv16i8One, {&AArch64::FPR128RegClass},
{Concat->getOperand(0).getReg(), IndexLoad->getOperand(0).getReg()});
constrainSelectedInstRegOperands(*TBL1, TII, TRI, RBI);
auto Copy =
MIRBuilder
.buildInstr(TargetOpcode::COPY, {I.getOperand(0).getReg()}, {})
.addReg(TBL1.getReg(0), 0, AArch64::dsub);
RBI.constrainGenericRegister(Copy.getReg(0), AArch64::FPR64RegClass, MRI);
I.eraseFromParent();
return true;
}
// For TBL2 we need to emit a REG_SEQUENCE to tie together two consecutive
// Q registers for regalloc.
auto RegSeq = MIRBuilder
.buildInstr(TargetOpcode::REG_SEQUENCE,
{&AArch64::QQRegClass}, {Src1Reg})
.addImm(AArch64::qsub0)
.addUse(Src2Reg)
.addImm(AArch64::qsub1);
auto TBL2 =
MIRBuilder.buildInstr(AArch64::TBLv16i8Two, {I.getOperand(0).getReg()},
{RegSeq, IndexLoad->getOperand(0).getReg()});
constrainSelectedInstRegOperands(*RegSeq, TII, TRI, RBI);
constrainSelectedInstRegOperands(*TBL2, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
MachineInstr *AArch64InstructionSelector::emitLaneInsert(
Optional<Register> DstReg, Register SrcReg, Register EltReg,
unsigned LaneIdx, const RegisterBank &RB,
MachineIRBuilder &MIRBuilder) const {
MachineInstr *InsElt = nullptr;
const TargetRegisterClass *DstRC = &AArch64::FPR128RegClass;
MachineRegisterInfo &MRI = *MIRBuilder.getMRI();
// Create a register to define with the insert if one wasn't passed in.
if (!DstReg)
DstReg = MRI.createVirtualRegister(DstRC);
unsigned EltSize = MRI.getType(EltReg).getSizeInBits();
unsigned Opc = getInsertVecEltOpInfo(RB, EltSize).first;
if (RB.getID() == AArch64::FPRRegBankID) {
auto InsSub = emitScalarToVector(EltSize, DstRC, EltReg, MIRBuilder);
InsElt = MIRBuilder.buildInstr(Opc, {*DstReg}, {SrcReg})
.addImm(LaneIdx)
.addUse(InsSub->getOperand(0).getReg())
.addImm(0);
} else {
InsElt = MIRBuilder.buildInstr(Opc, {*DstReg}, {SrcReg})
.addImm(LaneIdx)
.addUse(EltReg);
}
constrainSelectedInstRegOperands(*InsElt, TII, TRI, RBI);
return InsElt;
}
bool AArch64InstructionSelector::selectInsertElt(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_INSERT_VECTOR_ELT);
// Get information on the destination.
Register DstReg = I.getOperand(0).getReg();
const LLT DstTy = MRI.getType(DstReg);
unsigned VecSize = DstTy.getSizeInBits();
// Get information on the element we want to insert into the destination.
Register EltReg = I.getOperand(2).getReg();
const LLT EltTy = MRI.getType(EltReg);
unsigned EltSize = EltTy.getSizeInBits();
if (EltSize < 16 || EltSize > 64)
return false; // Don't support all element types yet.
// Find the definition of the index. Bail out if it's not defined by a
// G_CONSTANT.
Register IdxReg = I.getOperand(3).getReg();
auto VRegAndVal = getConstantVRegValWithLookThrough(IdxReg, MRI);
if (!VRegAndVal)
return false;
unsigned LaneIdx = VRegAndVal->Value;
// Perform the lane insert.
Register SrcReg = I.getOperand(1).getReg();
const RegisterBank &EltRB = *RBI.getRegBank(EltReg, MRI, TRI);
MachineIRBuilder MIRBuilder(I);
if (VecSize < 128) {
// If the vector we're inserting into is smaller than 128 bits, widen it
// to 128 to do the insert.
MachineInstr *ScalarToVec = emitScalarToVector(
VecSize, &AArch64::FPR128RegClass, SrcReg, MIRBuilder);
if (!ScalarToVec)
return false;
SrcReg = ScalarToVec->getOperand(0).getReg();
}
// Create an insert into a new FPR128 register.
// Note that if our vector is already 128 bits, we end up emitting an extra
// register.
MachineInstr *InsMI =
emitLaneInsert(None, SrcReg, EltReg, LaneIdx, EltRB, MIRBuilder);
if (VecSize < 128) {
// If we had to widen to perform the insert, then we have to demote back to
// the original size to get the result we want.
Register DemoteVec = InsMI->getOperand(0).getReg();
const TargetRegisterClass *RC =
getMinClassForRegBank(*RBI.getRegBank(DemoteVec, MRI, TRI), VecSize);
if (RC != &AArch64::FPR32RegClass && RC != &AArch64::FPR64RegClass) {
LLVM_DEBUG(dbgs() << "Unsupported register class!\n");
return false;
}
unsigned SubReg = 0;
if (!getSubRegForClass(RC, TRI, SubReg))
return false;
if (SubReg != AArch64::ssub && SubReg != AArch64::dsub) {
LLVM_DEBUG(dbgs() << "Unsupported destination size! (" << VecSize
<< "\n");
return false;
}
MIRBuilder.buildInstr(TargetOpcode::COPY, {DstReg}, {})
.addReg(DemoteVec, 0, SubReg);
RBI.constrainGenericRegister(DstReg, *RC, MRI);
} else {
// No widening needed.
InsMI->getOperand(0).setReg(DstReg);
constrainSelectedInstRegOperands(*InsMI, TII, TRI, RBI);
}
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectBuildVector(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_BUILD_VECTOR);
// Until we port more of the optimized selections, for now just use a vector
// insert sequence.
const LLT DstTy = MRI.getType(I.getOperand(0).getReg());
const LLT EltTy = MRI.getType(I.getOperand(1).getReg());
unsigned EltSize = EltTy.getSizeInBits();
if (EltSize < 16 || EltSize > 64)
return false; // Don't support all element types yet.
const RegisterBank &RB = *RBI.getRegBank(I.getOperand(1).getReg(), MRI, TRI);
MachineIRBuilder MIRBuilder(I);
const TargetRegisterClass *DstRC = &AArch64::FPR128RegClass;
MachineInstr *ScalarToVec =
emitScalarToVector(DstTy.getElementType().getSizeInBits(), DstRC,
I.getOperand(1).getReg(), MIRBuilder);
if (!ScalarToVec)
return false;
Register DstVec = ScalarToVec->getOperand(0).getReg();
unsigned DstSize = DstTy.getSizeInBits();
// Keep track of the last MI we inserted. Later on, we might be able to save
// a copy using it.
MachineInstr *PrevMI = nullptr;
for (unsigned i = 2, e = DstSize / EltSize + 1; i < e; ++i) {
// Note that if we don't do a subregister copy, we can end up making an
// extra register.
PrevMI = &*emitLaneInsert(None, DstVec, I.getOperand(i).getReg(), i - 1, RB,
MIRBuilder);
DstVec = PrevMI->getOperand(0).getReg();
}
// If DstTy's size in bits is less than 128, then emit a subregister copy
// from DstVec to the last register we've defined.
if (DstSize < 128) {
// Force this to be FPR using the destination vector.
const TargetRegisterClass *RC =
getMinClassForRegBank(*RBI.getRegBank(DstVec, MRI, TRI), DstSize);
if (!RC)
return false;
if (RC != &AArch64::FPR32RegClass && RC != &AArch64::FPR64RegClass) {
LLVM_DEBUG(dbgs() << "Unsupported register class!\n");
return false;
}
unsigned SubReg = 0;
if (!getSubRegForClass(RC, TRI, SubReg))
return false;
if (SubReg != AArch64::ssub && SubReg != AArch64::dsub) {
LLVM_DEBUG(dbgs() << "Unsupported destination size! (" << DstSize
<< "\n");
return false;
}
Register Reg = MRI.createVirtualRegister(RC);
Register DstReg = I.getOperand(0).getReg();
MIRBuilder.buildInstr(TargetOpcode::COPY, {DstReg}, {})
.addReg(DstVec, 0, SubReg);
MachineOperand &RegOp = I.getOperand(1);
RegOp.setReg(Reg);
RBI.constrainGenericRegister(DstReg, *RC, MRI);
} else {
// We don't need a subregister copy. Save a copy by re-using the
// destination register on the final insert.
assert(PrevMI && "PrevMI was null?");
PrevMI->getOperand(0).setReg(I.getOperand(0).getReg());
constrainSelectedInstRegOperands(*PrevMI, TII, TRI, RBI);
}
I.eraseFromParent();
return true;
}
/// Helper function to find an intrinsic ID on an a MachineInstr. Returns the
/// ID if it exists, and 0 otherwise.
static unsigned findIntrinsicID(MachineInstr &I) {
auto IntrinOp = find_if(I.operands(), [&](const MachineOperand &Op) {
return Op.isIntrinsicID();
});
if (IntrinOp == I.operands_end())
return 0;
return IntrinOp->getIntrinsicID();
}
bool AArch64InstructionSelector::selectIntrinsicWithSideEffects(
MachineInstr &I, MachineRegisterInfo &MRI) const {
// Find the intrinsic ID.
unsigned IntrinID = findIntrinsicID(I);
if (!IntrinID)
return false;
MachineIRBuilder MIRBuilder(I);
// Select the instruction.
switch (IntrinID) {
default:
return false;
case Intrinsic::trap:
MIRBuilder.buildInstr(AArch64::BRK, {}, {}).addImm(1);
break;
case Intrinsic::debugtrap:
if (!STI.isTargetWindows())
return false;
MIRBuilder.buildInstr(AArch64::BRK, {}, {}).addImm(0xF000);
break;
}
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectIntrinsic(
MachineInstr &I, MachineRegisterInfo &MRI) const {
unsigned IntrinID = findIntrinsicID(I);
if (!IntrinID)
return false;
MachineIRBuilder MIRBuilder(I);
switch (IntrinID) {
default:
break;
case Intrinsic::aarch64_crypto_sha1h:
Register DstReg = I.getOperand(0).getReg();
Register SrcReg = I.getOperand(2).getReg();
// FIXME: Should this be an assert?
if (MRI.getType(DstReg).getSizeInBits() != 32 ||
MRI.getType(SrcReg).getSizeInBits() != 32)
return false;
// The operation has to happen on FPRs. Set up some new FPR registers for
// the source and destination if they are on GPRs.
if (RBI.getRegBank(SrcReg, MRI, TRI)->getID() != AArch64::FPRRegBankID) {
SrcReg = MRI.createVirtualRegister(&AArch64::FPR32RegClass);
MIRBuilder.buildCopy({SrcReg}, {I.getOperand(2)});
// Make sure the copy ends up getting constrained properly.
RBI.constrainGenericRegister(I.getOperand(2).getReg(),
AArch64::GPR32RegClass, MRI);
}
if (RBI.getRegBank(DstReg, MRI, TRI)->getID() != AArch64::FPRRegBankID)
DstReg = MRI.createVirtualRegister(&AArch64::FPR32RegClass);
// Actually insert the instruction.
auto SHA1Inst = MIRBuilder.buildInstr(AArch64::SHA1Hrr, {DstReg}, {SrcReg});
constrainSelectedInstRegOperands(*SHA1Inst, TII, TRI, RBI);
// Did we create a new register for the destination?
if (DstReg != I.getOperand(0).getReg()) {
// Yep. Copy the result of the instruction back into the original
// destination.
MIRBuilder.buildCopy({I.getOperand(0)}, {DstReg});
RBI.constrainGenericRegister(I.getOperand(0).getReg(),
AArch64::GPR32RegClass, MRI);
}
I.eraseFromParent();
return true;
}
return false;
}
static Optional<uint64_t> getImmedFromMO(const MachineOperand &Root) {
auto &MI = *Root.getParent();
auto &MBB = *MI.getParent();
auto &MF = *MBB.getParent();
auto &MRI = MF.getRegInfo();
uint64_t Immed;
if (Root.isImm())
Immed = Root.getImm();
else if (Root.isCImm())
Immed = Root.getCImm()->getZExtValue();
else if (Root.isReg()) {
auto ValAndVReg =
getConstantVRegValWithLookThrough(Root.getReg(), MRI, true);
if (!ValAndVReg)
return None;
Immed = ValAndVReg->Value;
} else
return None;
return Immed;
}
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectShiftA_32(const MachineOperand &Root) const {
auto MaybeImmed = getImmedFromMO(Root);
if (MaybeImmed == None || *MaybeImmed > 31)
return None;
uint64_t Enc = (32 - *MaybeImmed) & 0x1f;
return {{[=](MachineInstrBuilder &MIB) { MIB.addImm(Enc); }}};
}
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectShiftB_32(const MachineOperand &Root) const {
auto MaybeImmed = getImmedFromMO(Root);
if (MaybeImmed == None || *MaybeImmed > 31)
return None;
uint64_t Enc = 31 - *MaybeImmed;
return {{[=](MachineInstrBuilder &MIB) { MIB.addImm(Enc); }}};
}
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectShiftA_64(const MachineOperand &Root) const {
auto MaybeImmed = getImmedFromMO(Root);
if (MaybeImmed == None || *MaybeImmed > 63)
return None;
uint64_t Enc = (64 - *MaybeImmed) & 0x3f;
return {{[=](MachineInstrBuilder &MIB) { MIB.addImm(Enc); }}};
}
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectShiftB_64(const MachineOperand &Root) const {
auto MaybeImmed = getImmedFromMO(Root);
if (MaybeImmed == None || *MaybeImmed > 63)
return None;
uint64_t Enc = 63 - *MaybeImmed;
return {{[=](MachineInstrBuilder &MIB) { MIB.addImm(Enc); }}};
}
/// Helper to select an immediate value that can be represented as a 12-bit
/// value shifted left by either 0 or 12. If it is possible to do so, return
/// the immediate and shift value. If not, return None.
///
/// Used by selectArithImmed and selectNegArithImmed.
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::select12BitValueWithLeftShift(
uint64_t Immed) const {
unsigned ShiftAmt;
if (Immed >> 12 == 0) {
ShiftAmt = 0;
} else if ((Immed & 0xfff) == 0 && Immed >> 24 == 0) {
ShiftAmt = 12;
Immed = Immed >> 12;
} else
return None;
unsigned ShVal = AArch64_AM::getShifterImm(AArch64_AM::LSL, ShiftAmt);
return {{
[=](MachineInstrBuilder &MIB) { MIB.addImm(Immed); },
[=](MachineInstrBuilder &MIB) { MIB.addImm(ShVal); },
}};
}
/// SelectArithImmed - Select an immediate value that can be represented as
/// a 12-bit value shifted left by either 0 or 12. If so, return true with
/// Val set to the 12-bit value and Shift set to the shifter operand.
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectArithImmed(MachineOperand &Root) const {
// This function is called from the addsub_shifted_imm ComplexPattern,
// which lists [imm] as the list of opcode it's interested in, however
// we still need to check whether the operand is actually an immediate
// here because the ComplexPattern opcode list is only used in
// root-level opcode matching.
auto MaybeImmed = getImmedFromMO(Root);
if (MaybeImmed == None)
return None;
return select12BitValueWithLeftShift(*MaybeImmed);
}
/// SelectNegArithImmed - As above, but negates the value before trying to
/// select it.
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectNegArithImmed(MachineOperand &Root) const {
// We need a register here, because we need to know if we have a 64 or 32
// bit immediate.
if (!Root.isReg())
return None;
auto MaybeImmed = getImmedFromMO(Root);
if (MaybeImmed == None)
return None;
uint64_t Immed = *MaybeImmed;
// This negation is almost always valid, but "cmp wN, #0" and "cmn wN, #0"
// have the opposite effect on the C flag, so this pattern mustn't match under
// those circumstances.
if (Immed == 0)
return None;
// Check if we're dealing with a 32-bit type on the root or a 64-bit type on
// the root.
MachineRegisterInfo &MRI = Root.getParent()->getMF()->getRegInfo();
if (MRI.getType(Root.getReg()).getSizeInBits() == 32)
Immed = ~((uint32_t)Immed) + 1;
else
Immed = ~Immed + 1ULL;
if (Immed & 0xFFFFFFFFFF000000ULL)
return None;
Immed &= 0xFFFFFFULL;
return select12BitValueWithLeftShift(Immed);
}
/// Return true if it is worth folding MI into an extended register. That is,
/// if it's safe to pull it into the addressing mode of a load or store as a
/// shift.
bool AArch64InstructionSelector::isWorthFoldingIntoExtendedReg(
MachineInstr &MI, const MachineRegisterInfo &MRI) const {
// Always fold if there is one use, or if we're optimizing for size.
Register DefReg = MI.getOperand(0).getReg();
if (MRI.hasOneUse(DefReg) ||
MI.getParent()->getParent()->getFunction().hasMinSize())
return true;
// It's better to avoid folding and recomputing shifts when we don't have a
// fastpath.
if (!STI.hasLSLFast())
return false;
// We have a fastpath, so folding a shift in and potentially computing it
// many times may be beneficial. Check if this is only used in memory ops.
// If it is, then we should fold.
return all_of(MRI.use_instructions(DefReg),
[](MachineInstr &Use) { return Use.mayLoadOrStore(); });
}
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectExtendedSHL(
MachineOperand &Root, MachineOperand &Base, MachineOperand &Offset,
unsigned SizeInBytes, bool WantsExt) const {
assert(Base.isReg() && "Expected base to be a register operand");
assert(Offset.isReg() && "Expected offset to be a register operand");
MachineRegisterInfo &MRI = Root.getParent()->getMF()->getRegInfo();
MachineInstr *OffsetInst = MRI.getVRegDef(Offset.getReg());
if (!OffsetInst)
return None;
unsigned OffsetOpc = OffsetInst->getOpcode();
if (OffsetOpc != TargetOpcode::G_SHL && OffsetOpc != TargetOpcode::G_MUL)
return None;
// Make sure that the memory op is a valid size.
int64_t LegalShiftVal = Log2_32(SizeInBytes);
if (LegalShiftVal == 0)
return None;
if (!isWorthFoldingIntoExtendedReg(*OffsetInst, MRI))
return None;
// Now, try to find the specific G_CONSTANT. Start by assuming that the
// register we will offset is the LHS, and the register containing the
// constant is the RHS.
Register OffsetReg = OffsetInst->getOperand(1).getReg();
Register ConstantReg = OffsetInst->getOperand(2).getReg();
auto ValAndVReg = getConstantVRegValWithLookThrough(ConstantReg, MRI);
if (!ValAndVReg) {
// We didn't get a constant on the RHS. If the opcode is a shift, then
// we're done.
if (OffsetOpc == TargetOpcode::G_SHL)
return None;
// If we have a G_MUL, we can use either register. Try looking at the RHS.
std::swap(OffsetReg, ConstantReg);
ValAndVReg = getConstantVRegValWithLookThrough(ConstantReg, MRI);
if (!ValAndVReg)
return None;
}
// The value must fit into 3 bits, and must be positive. Make sure that is
// true.
int64_t ImmVal = ValAndVReg->Value;
// Since we're going to pull this into a shift, the constant value must be
// a power of 2. If we got a multiply, then we need to check this.
if (OffsetOpc == TargetOpcode::G_MUL) {
if (!isPowerOf2_32(ImmVal))
return None;
// Got a power of 2. So, the amount we'll shift is the log base-2 of that.
ImmVal = Log2_32(ImmVal);
}
if ((ImmVal & 0x7) != ImmVal)
return None;
// We are only allowed to shift by LegalShiftVal. This shift value is built
// into the instruction, so we can't just use whatever we want.
if (ImmVal != LegalShiftVal)
return None;
unsigned SignExtend = 0;
if (WantsExt) {
// Check if the offset is defined by an extend.
MachineInstr *ExtInst = getDefIgnoringCopies(OffsetReg, MRI);
auto Ext = getExtendTypeForInst(*ExtInst, MRI, true);
if (Ext == AArch64_AM::InvalidShiftExtend)
return None;
SignExtend = Ext == AArch64_AM::SXTW;
// Need a 32-bit wide register here.
MachineIRBuilder MIB(*MRI.getVRegDef(Root.getReg()));
OffsetReg = ExtInst->getOperand(1).getReg();
OffsetReg = narrowExtendRegIfNeeded(OffsetReg, MIB);
}
// We can use the LHS of the GEP as the base, and the LHS of the shift as an
// offset. Signify that we are shifting by setting the shift flag to 1.
return {{[=](MachineInstrBuilder &MIB) { MIB.addUse(Base.getReg()); },
[=](MachineInstrBuilder &MIB) { MIB.addUse(OffsetReg); },
[=](MachineInstrBuilder &MIB) {
// Need to add both immediates here to make sure that they are both
// added to the instruction.
MIB.addImm(SignExtend);
MIB.addImm(1);
}}};
}
/// This is used for computing addresses like this:
///
/// ldr x1, [x2, x3, lsl #3]
///
/// Where x2 is the base register, and x3 is an offset register. The shift-left
/// is a constant value specific to this load instruction. That is, we'll never
/// see anything other than a 3 here (which corresponds to the size of the
/// element being loaded.)
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectAddrModeShiftedExtendXReg(
MachineOperand &Root, unsigned SizeInBytes) const {
if (!Root.isReg())
return None;
MachineRegisterInfo &MRI = Root.getParent()->getMF()->getRegInfo();
// We want to find something like this:
//
// val = G_CONSTANT LegalShiftVal
// shift = G_SHL off_reg val
// ptr = G_PTR_ADD base_reg shift
// x = G_LOAD ptr
//
// And fold it into this addressing mode:
//
// ldr x, [base_reg, off_reg, lsl #LegalShiftVal]
// Check if we can find the G_PTR_ADD.
MachineInstr *PtrAdd =
getOpcodeDef(TargetOpcode::G_PTR_ADD, Root.getReg(), MRI);
if (!PtrAdd || !isWorthFoldingIntoExtendedReg(*PtrAdd, MRI))
return None;
// Now, try to match an opcode which will match our specific offset.
// We want a G_SHL or a G_MUL.
MachineInstr *OffsetInst =
getDefIgnoringCopies(PtrAdd->getOperand(2).getReg(), MRI);
return selectExtendedSHL(Root, PtrAdd->getOperand(1),
OffsetInst->getOperand(0), SizeInBytes,
/*WantsExt=*/false);
}
/// This is used for computing addresses like this:
///
/// ldr x1, [x2, x3]
///
/// Where x2 is the base register, and x3 is an offset register.
///
/// When possible (or profitable) to fold a G_PTR_ADD into the address calculation,
/// this will do so. Otherwise, it will return None.
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectAddrModeRegisterOffset(
MachineOperand &Root) const {
MachineRegisterInfo &MRI = Root.getParent()->getMF()->getRegInfo();
// We need a GEP.
MachineInstr *Gep = MRI.getVRegDef(Root.getReg());
if (!Gep || Gep->getOpcode() != TargetOpcode::G_PTR_ADD)
return None;
// If this is used more than once, let's not bother folding.
// TODO: Check if they are memory ops. If they are, then we can still fold
// without having to recompute anything.
if (!MRI.hasOneUse(Gep->getOperand(0).getReg()))
return None;
// Base is the GEP's LHS, offset is its RHS.
return {{[=](MachineInstrBuilder &MIB) {
MIB.addUse(Gep->getOperand(1).getReg());
},
[=](MachineInstrBuilder &MIB) {
MIB.addUse(Gep->getOperand(2).getReg());
},
[=](MachineInstrBuilder &MIB) {
// Need to add both immediates here to make sure that they are both
// added to the instruction.
MIB.addImm(0);
MIB.addImm(0);
}}};
}
/// This is intended to be equivalent to selectAddrModeXRO in
/// AArch64ISelDAGtoDAG. It's used for selecting X register offset loads.
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectAddrModeXRO(MachineOperand &Root,
unsigned SizeInBytes) const {
MachineRegisterInfo &MRI = Root.getParent()->getMF()->getRegInfo();
// If we have a constant offset, then we probably don't want to match a
// register offset.
if (isBaseWithConstantOffset(Root, MRI))
return None;
// Try to fold shifts into the addressing mode.
auto AddrModeFns = selectAddrModeShiftedExtendXReg(Root, SizeInBytes);
if (AddrModeFns)
return AddrModeFns;
// If that doesn't work, see if it's possible to fold in registers from
// a GEP.
return selectAddrModeRegisterOffset(Root);
}
/// This is used for computing addresses like this:
///
/// ldr x0, [xBase, wOffset, sxtw #LegalShiftVal]
///
/// Where we have a 64-bit base register, a 32-bit offset register, and an
/// extend (which may or may not be signed).
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectAddrModeWRO(MachineOperand &Root,
unsigned SizeInBytes) const {
MachineRegisterInfo &MRI = Root.getParent()->getMF()->getRegInfo();
MachineInstr *PtrAdd =
getOpcodeDef(TargetOpcode::G_PTR_ADD, Root.getReg(), MRI);
if (!PtrAdd || !isWorthFoldingIntoExtendedReg(*PtrAdd, MRI))
return None;
MachineOperand &LHS = PtrAdd->getOperand(1);
MachineOperand &RHS = PtrAdd->getOperand(2);
MachineInstr *OffsetInst = getDefIgnoringCopies(RHS.getReg(), MRI);
// The first case is the same as selectAddrModeXRO, except we need an extend.
// In this case, we try to find a shift and extend, and fold them into the
// addressing mode.
//
// E.g.
//
// off_reg = G_Z/S/ANYEXT ext_reg
// val = G_CONSTANT LegalShiftVal
// shift = G_SHL off_reg val
// ptr = G_PTR_ADD base_reg shift
// x = G_LOAD ptr
//
// In this case we can get a load like this:
//
// ldr x0, [base_reg, ext_reg, sxtw #LegalShiftVal]
auto ExtendedShl = selectExtendedSHL(Root, LHS, OffsetInst->getOperand(0),
SizeInBytes, /*WantsExt=*/true);
if (ExtendedShl)
return ExtendedShl;
// There was no shift. We can try and fold a G_Z/S/ANYEXT in alone though.
//
// e.g.
// ldr something, [base_reg, ext_reg, sxtw]
if (!isWorthFoldingIntoExtendedReg(*OffsetInst, MRI))
return None;
// Check if this is an extend. We'll get an extend type if it is.
AArch64_AM::ShiftExtendType Ext =
getExtendTypeForInst(*OffsetInst, MRI, /*IsLoadStore=*/true);
if (Ext == AArch64_AM::InvalidShiftExtend)
return None;
// Need a 32-bit wide register.
MachineIRBuilder MIB(*PtrAdd);
Register ExtReg =
narrowExtendRegIfNeeded(OffsetInst->getOperand(1).getReg(), MIB);
unsigned SignExtend = Ext == AArch64_AM::SXTW;
// Base is LHS, offset is ExtReg.
return {{[=](MachineInstrBuilder &MIB) { MIB.addUse(LHS.getReg()); },
[=](MachineInstrBuilder &MIB) { MIB.addUse(ExtReg); },
[=](MachineInstrBuilder &MIB) {
MIB.addImm(SignExtend);
MIB.addImm(0);
}}};
}
/// Select a "register plus unscaled signed 9-bit immediate" address. This
/// should only match when there is an offset that is not valid for a scaled
/// immediate addressing mode. The "Size" argument is the size in bytes of the
/// memory reference, which is needed here to know what is valid for a scaled
/// immediate.
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectAddrModeUnscaled(MachineOperand &Root,
unsigned Size) const {
MachineRegisterInfo &MRI =
Root.getParent()->getParent()->getParent()->getRegInfo();
if (!Root.isReg())
return None;
if (!isBaseWithConstantOffset(Root, MRI))
return None;
MachineInstr *RootDef = MRI.getVRegDef(Root.getReg());
if (!RootDef)
return None;
MachineOperand &OffImm = RootDef->getOperand(2);
if (!OffImm.isReg())
return None;
MachineInstr *RHS = MRI.getVRegDef(OffImm.getReg());
if (!RHS || RHS->getOpcode() != TargetOpcode::G_CONSTANT)
return None;
int64_t RHSC;
MachineOperand &RHSOp1 = RHS->getOperand(1);
if (!RHSOp1.isCImm() || RHSOp1.getCImm()->getBitWidth() > 64)
return None;
RHSC = RHSOp1.getCImm()->getSExtValue();
// If the offset is valid as a scaled immediate, don't match here.
if ((RHSC & (Size - 1)) == 0 && RHSC >= 0 && RHSC < (0x1000 << Log2_32(Size)))
return None;
if (RHSC >= -256 && RHSC < 256) {
MachineOperand &Base = RootDef->getOperand(1);
return {{
[=](MachineInstrBuilder &MIB) { MIB.add(Base); },
[=](MachineInstrBuilder &MIB) { MIB.addImm(RHSC); },
}};
}
return None;
}
/// Select a "register plus scaled unsigned 12-bit immediate" address. The
/// "Size" argument is the size in bytes of the memory reference, which
/// determines the scale.
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectAddrModeIndexed(MachineOperand &Root,
unsigned Size) const {
MachineRegisterInfo &MRI =
Root.getParent()->getParent()->getParent()->getRegInfo();
if (!Root.isReg())
return None;
MachineInstr *RootDef = MRI.getVRegDef(Root.getReg());
if (!RootDef)
return None;
if (RootDef->getOpcode() == TargetOpcode::G_FRAME_INDEX) {
return {{
[=](MachineInstrBuilder &MIB) { MIB.add(RootDef->getOperand(1)); },
[=](MachineInstrBuilder &MIB) { MIB.addImm(0); },
}};
}
if (isBaseWithConstantOffset(Root, MRI)) {
MachineOperand &LHS = RootDef->getOperand(1);
MachineOperand &RHS = RootDef->getOperand(2);
MachineInstr *LHSDef = MRI.getVRegDef(LHS.getReg());
MachineInstr *RHSDef = MRI.getVRegDef(RHS.getReg());
if (LHSDef && RHSDef) {
int64_t RHSC = (int64_t)RHSDef->getOperand(1).getCImm()->getZExtValue();
unsigned Scale = Log2_32(Size);
if ((RHSC & (Size - 1)) == 0 && RHSC >= 0 && RHSC < (0x1000 << Scale)) {
if (LHSDef->getOpcode() == TargetOpcode::G_FRAME_INDEX)
return {{
[=](MachineInstrBuilder &MIB) { MIB.add(LHSDef->getOperand(1)); },
[=](MachineInstrBuilder &MIB) { MIB.addImm(RHSC >> Scale); },
}};
return {{
[=](MachineInstrBuilder &MIB) { MIB.add(LHS); },
[=](MachineInstrBuilder &MIB) { MIB.addImm(RHSC >> Scale); },
}};
}
}
}
// Before falling back to our general case, check if the unscaled
// instructions can handle this. If so, that's preferable.
if (selectAddrModeUnscaled(Root, Size).hasValue())
return None;
return {{
[=](MachineInstrBuilder &MIB) { MIB.add(Root); },
[=](MachineInstrBuilder &MIB) { MIB.addImm(0); },
}};
}
/// Given a shift instruction, return the correct shift type for that
/// instruction.
static AArch64_AM::ShiftExtendType getShiftTypeForInst(MachineInstr &MI) {
// TODO: Handle AArch64_AM::ROR
switch (MI.getOpcode()) {
default:
return AArch64_AM::InvalidShiftExtend;
case TargetOpcode::G_SHL:
return AArch64_AM::LSL;
case TargetOpcode::G_LSHR:
return AArch64_AM::LSR;
case TargetOpcode::G_ASHR:
return AArch64_AM::ASR;
}
}
/// Select a "shifted register" operand. If the value is not shifted, set the
/// shift operand to a default value of "lsl 0".
///
/// TODO: Allow shifted register to be rotated in logical instructions.
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectShiftedRegister(MachineOperand &Root) const {
if (!Root.isReg())
return None;
MachineRegisterInfo &MRI =
Root.getParent()->getParent()->getParent()->getRegInfo();
// Check if the operand is defined by an instruction which corresponds to
// a ShiftExtendType. E.g. a G_SHL, G_LSHR, etc.
//
// TODO: Handle AArch64_AM::ROR for logical instructions.
MachineInstr *ShiftInst = MRI.getVRegDef(Root.getReg());
if (!ShiftInst)
return None;
AArch64_AM::ShiftExtendType ShType = getShiftTypeForInst(*ShiftInst);
if (ShType == AArch64_AM::InvalidShiftExtend)
return None;
if (!isWorthFoldingIntoExtendedReg(*ShiftInst, MRI))
return None;
// Need an immediate on the RHS.
MachineOperand &ShiftRHS = ShiftInst->getOperand(2);
auto Immed = getImmedFromMO(ShiftRHS);
if (!Immed)
return None;
// We have something that we can fold. Fold in the shift's LHS and RHS into
// the instruction.
MachineOperand &ShiftLHS = ShiftInst->getOperand(1);
Register ShiftReg = ShiftLHS.getReg();
unsigned NumBits = MRI.getType(ShiftReg).getSizeInBits();
unsigned Val = *Immed & (NumBits - 1);
unsigned ShiftVal = AArch64_AM::getShifterImm(ShType, Val);
return {{[=](MachineInstrBuilder &MIB) { MIB.addUse(ShiftReg); },
[=](MachineInstrBuilder &MIB) { MIB.addImm(ShiftVal); }}};
}
AArch64_AM::ShiftExtendType AArch64InstructionSelector::getExtendTypeForInst(
MachineInstr &MI, MachineRegisterInfo &MRI, bool IsLoadStore) const {
unsigned Opc = MI.getOpcode();
// Handle explicit extend instructions first.
if (Opc == TargetOpcode::G_SEXT || Opc == TargetOpcode::G_SEXT_INREG) {
unsigned Size = MRI.getType(MI.getOperand(1).getReg()).getSizeInBits();
assert(Size != 64 && "Extend from 64 bits?");
switch (Size) {
case 8:
return AArch64_AM::SXTB;
case 16:
return AArch64_AM::SXTH;
case 32:
return AArch64_AM::SXTW;
default:
return AArch64_AM::InvalidShiftExtend;
}
}
if (Opc == TargetOpcode::G_ZEXT || Opc == TargetOpcode::G_ANYEXT) {
unsigned Size = MRI.getType(MI.getOperand(1).getReg()).getSizeInBits();
assert(Size != 64 && "Extend from 64 bits?");
switch (Size) {
case 8:
return AArch64_AM::UXTB;
case 16:
return AArch64_AM::UXTH;
case 32:
return AArch64_AM::UXTW;
default:
return AArch64_AM::InvalidShiftExtend;
}
}
// Don't have an explicit extend. Try to handle a G_AND with a constant mask
// on the RHS.
if (Opc != TargetOpcode::G_AND)
return AArch64_AM::InvalidShiftExtend;
Optional<uint64_t> MaybeAndMask = getImmedFromMO(MI.getOperand(2));
if (!MaybeAndMask)
return AArch64_AM::InvalidShiftExtend;
uint64_t AndMask = *MaybeAndMask;
switch (AndMask) {
default:
return AArch64_AM::InvalidShiftExtend;
case 0xFF:
return !IsLoadStore ? AArch64_AM::UXTB : AArch64_AM::InvalidShiftExtend;
case 0xFFFF:
return !IsLoadStore ? AArch64_AM::UXTH : AArch64_AM::InvalidShiftExtend;
case 0xFFFFFFFF:
return AArch64_AM::UXTW;
}
}
Register AArch64InstructionSelector::narrowExtendRegIfNeeded(
Register ExtReg, MachineIRBuilder &MIB) const {
MachineRegisterInfo &MRI = *MIB.getMRI();
if (MRI.getType(ExtReg).getSizeInBits() == 32)
return ExtReg;
// Insert a copy to move ExtReg to GPR32.
Register NarrowReg = MRI.createVirtualRegister(&AArch64::GPR32RegClass);
auto Copy = MIB.buildCopy({NarrowReg}, {ExtReg});
// Select the copy into a subregister copy.
selectCopy(*Copy, TII, MRI, TRI, RBI);
return Copy.getReg(0);
}
/// Select an "extended register" operand. This operand folds in an extend
/// followed by an optional left shift.
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::selectArithExtendedRegister(
MachineOperand &Root) const {
if (!Root.isReg())
return None;
MachineRegisterInfo &MRI =
Root.getParent()->getParent()->getParent()->getRegInfo();
uint64_t ShiftVal = 0;
Register ExtReg;
AArch64_AM::ShiftExtendType Ext;
MachineInstr *RootDef = getDefIgnoringCopies(Root.getReg(), MRI);
if (!RootDef)
return None;
if (!isWorthFoldingIntoExtendedReg(*RootDef, MRI))
return None;
// Check if we can fold a shift and an extend.
if (RootDef->getOpcode() == TargetOpcode::G_SHL) {
// Look for a constant on the RHS of the shift.
MachineOperand &RHS = RootDef->getOperand(2);
Optional<uint64_t> MaybeShiftVal = getImmedFromMO(RHS);
if (!MaybeShiftVal)
return None;
ShiftVal = *MaybeShiftVal;
if (ShiftVal > 4)
return None;
// Look for a valid extend instruction on the LHS of the shift.
MachineOperand &LHS = RootDef->getOperand(1);
MachineInstr *ExtDef = getDefIgnoringCopies(LHS.getReg(), MRI);
if (!ExtDef)
return None;
Ext = getExtendTypeForInst(*ExtDef, MRI);
if (Ext == AArch64_AM::InvalidShiftExtend)
return None;
ExtReg = ExtDef->getOperand(1).getReg();
} else {
// Didn't get a shift. Try just folding an extend.
Ext = getExtendTypeForInst(*RootDef, MRI);
if (Ext == AArch64_AM::InvalidShiftExtend)
return None;
ExtReg = RootDef->getOperand(1).getReg();
// If we have a 32 bit instruction which zeroes out the high half of a
// register, we get an implicit zero extend for free. Check if we have one.
// FIXME: We actually emit the extend right now even though we don't have
// to.
if (Ext == AArch64_AM::UXTW && MRI.getType(ExtReg).getSizeInBits() == 32) {
MachineInstr *ExtInst = MRI.getVRegDef(ExtReg);
if (ExtInst && isDef32(*ExtInst))
return None;
}
}
// We require a GPR32 here. Narrow the ExtReg if needed using a subregister
// copy.
MachineIRBuilder MIB(*RootDef);
ExtReg = narrowExtendRegIfNeeded(ExtReg, MIB);
return {{[=](MachineInstrBuilder &MIB) { MIB.addUse(ExtReg); },
[=](MachineInstrBuilder &MIB) {
MIB.addImm(getArithExtendImm(Ext, ShiftVal));
}}};
}
void AArch64InstructionSelector::renderTruncImm(MachineInstrBuilder &MIB,
const MachineInstr &MI,
int OpIdx) const {
const MachineRegisterInfo &MRI = MI.getParent()->getParent()->getRegInfo();
assert(MI.getOpcode() == TargetOpcode::G_CONSTANT && OpIdx == -1 &&
"Expected G_CONSTANT");
Optional<int64_t> CstVal = getConstantVRegVal(MI.getOperand(0).getReg(), MRI);
assert(CstVal && "Expected constant value");
MIB.addImm(CstVal.getValue());
}
void AArch64InstructionSelector::renderLogicalImm32(
MachineInstrBuilder &MIB, const MachineInstr &I, int OpIdx) const {
assert(I.getOpcode() == TargetOpcode::G_CONSTANT && OpIdx == -1 &&
"Expected G_CONSTANT");
uint64_t CstVal = I.getOperand(1).getCImm()->getZExtValue();
uint64_t Enc = AArch64_AM::encodeLogicalImmediate(CstVal, 32);
MIB.addImm(Enc);
}
void AArch64InstructionSelector::renderLogicalImm64(
MachineInstrBuilder &MIB, const MachineInstr &I, int OpIdx) const {
assert(I.getOpcode() == TargetOpcode::G_CONSTANT && OpIdx == -1 &&
"Expected G_CONSTANT");
uint64_t CstVal = I.getOperand(1).getCImm()->getZExtValue();
uint64_t Enc = AArch64_AM::encodeLogicalImmediate(CstVal, 64);
MIB.addImm(Enc);
}
bool AArch64InstructionSelector::isLoadStoreOfNumBytes(
const MachineInstr &MI, unsigned NumBytes) const {
if (!MI.mayLoadOrStore())
return false;
assert(MI.hasOneMemOperand() &&
"Expected load/store to have only one mem op!");
return (*MI.memoperands_begin())->getSize() == NumBytes;
}
bool AArch64InstructionSelector::isDef32(const MachineInstr &MI) const {
const MachineRegisterInfo &MRI = MI.getParent()->getParent()->getRegInfo();
if (MRI.getType(MI.getOperand(0).getReg()).getSizeInBits() != 32)
return false;
// Only return true if we know the operation will zero-out the high half of
// the 64-bit register. Truncates can be subregister copies, which don't
// zero out the high bits. Copies and other copy-like instructions can be
// fed by truncates, or could be lowered as subregister copies.
switch (MI.getOpcode()) {
default:
return true;
case TargetOpcode::COPY:
case TargetOpcode::G_BITCAST:
case TargetOpcode::G_TRUNC:
case TargetOpcode::G_PHI:
return false;
}
}
namespace llvm {
InstructionSelector *
createAArch64InstructionSelector(const AArch64TargetMachine &TM,
AArch64Subtarget &Subtarget,
AArch64RegisterBankInfo &RBI) {
return new AArch64InstructionSelector(TM, Subtarget, RBI);
}
}