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llvm / llvm-project / llvm / 49a8cd29ed54c64b3b1fd80612508262a4a7b519 / . / lib / Target / AArch64 / GISel / 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 "AArch64GlobalISelUtils.h"
#include "AArch64InstrInfo.h"
#include "AArch64MachineFunctionInfo.h"
#include "AArch64RegisterBankInfo.h"
#include "AArch64RegisterInfo.h"
#include "AArch64Subtarget.h"
#include "AArch64TargetMachine.h"
#include "AArch64GlobalISelUtils.h"
#include "MCTargetDesc/AArch64AddressingModes.h"
#include "MCTargetDesc/AArch64MCTargetDesc.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/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/CodeGen/TargetOpcodes.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/IntrinsicsAArch64.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#define DEBUG_TYPE "aarch64-isel"
using namespace llvm;
using namespace MIPatternMatch;
using namespace AArch64GISelUtils;
namespace llvm {
class BlockFrequencyInfo;
class ProfileSummaryInfo;
}
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, ProfileSummaryInfo *PSI,
BlockFrequencyInfo *BFI) override {
InstructionSelector::setupMF(MF, KB, CoverageInfo, PSI, BFI);
// 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);
MFReturnAddr = Register();
processPHIs(MF);
}
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.
// Returns true if the instruction was modified.
bool preISelLower(MachineInstr &I);
// An early selection function that runs before the selectImpl() call.
bool earlySelect(MachineInstr &I) const;
// Do some preprocessing of G_PHIs before we begin selection.
void processPHIs(MachineFunction &MF);
bool earlySelectSHL(MachineInstr &I, MachineRegisterInfo &MRI) const;
/// Eliminate same-sized cross-bank copies into stores before selectImpl().
bool contractCrossBankCopyIntoStore(MachineInstr &I,
MachineRegisterInfo &MRI);
bool convertPtrAddToAdd(MachineInstr &I, MachineRegisterInfo &MRI);
bool selectVaStartAAPCS(MachineInstr &I, MachineFunction &MF,
MachineRegisterInfo &MRI) const;
bool selectVaStartDarwin(MachineInstr &I, MachineFunction &MF,
MachineRegisterInfo &MRI) const;
///@{
/// Helper functions for selectCompareBranch.
bool selectCompareBranchFedByFCmp(MachineInstr &I, MachineInstr &FCmp,
MachineIRBuilder &MIB) const;
bool selectCompareBranchFedByICmp(MachineInstr &I, MachineInstr &ICmp,
MachineIRBuilder &MIB) const;
bool tryOptCompareBranchFedByICmp(MachineInstr &I, MachineInstr &ICmp,
MachineIRBuilder &MIB) const;
bool tryOptAndIntoCompareBranch(MachineInstr &AndInst, bool Invert,
MachineBasicBlock *DstMBB,
MachineIRBuilder &MIB) const;
///@}
bool selectCompareBranch(MachineInstr &I, MachineFunction &MF,
MachineRegisterInfo &MRI) const;
bool selectVectorAshrLshr(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;
/// Emit a sequence of instructions representing a constant \p CV for a
/// vector register \p Dst. (E.g. a MOV, or a load from a constant pool.)
///
/// \returns the last instruction in the sequence on success, and nullptr
/// otherwise.
MachineInstr *emitConstantVector(Register Dst, Constant *CV,
MachineIRBuilder &MIRBuilder,
MachineRegisterInfo &MRI) const;
bool selectInsertElt(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool tryOptConstantBuildVec(MachineInstr &MI, LLT DstTy,
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);
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;
bool selectReduction(MachineInstr &I, MachineRegisterInfo &MRI) const;
unsigned emitConstantPoolEntry(const Constant *CPVal,
MachineFunction &MF) const;
MachineInstr *emitLoadFromConstantPool(const Constant *CPVal,
MachineIRBuilder &MIRBuilder) const;
// Emit a vector concat operation.
MachineInstr *emitVectorConcat(Optional<Register> Dst, Register Op1,
Register Op2,
MachineIRBuilder &MIRBuilder) const;
// Emit an integer compare between LHS and RHS, which checks for Predicate.
MachineInstr *emitIntegerCompare(MachineOperand &LHS, MachineOperand &RHS,
MachineOperand &Predicate,
MachineIRBuilder &MIRBuilder) const;
/// Emit a floating point comparison between \p LHS and \p RHS.
/// \p Pred if given is the intended predicate to use.
MachineInstr *emitFPCompare(Register LHS, Register RHS,
MachineIRBuilder &MIRBuilder,
Optional<CmpInst::Predicate> = None) const;
MachineInstr *emitInstr(unsigned Opcode,
std::initializer_list<llvm::DstOp> DstOps,
std::initializer_list<llvm::SrcOp> SrcOps,
MachineIRBuilder &MIRBuilder,
const ComplexRendererFns &RenderFns = None) const;
/// Helper function to emit an add or sub instruction.
///
/// \p AddrModeAndSizeToOpcode must contain each of the opcode variants above
/// in a specific order.
///
/// Below is an example of the expected input to \p AddrModeAndSizeToOpcode.
///
/// \code
/// const std::array<std::array<unsigned, 2>, 4> Table {
/// {{AArch64::ADDXri, AArch64::ADDWri},
/// {AArch64::ADDXrs, AArch64::ADDWrs},
/// {AArch64::ADDXrr, AArch64::ADDWrr},
/// {AArch64::SUBXri, AArch64::SUBWri},
/// {AArch64::ADDXrx, AArch64::ADDWrx}}};
/// \endcode
///
/// Each row in the table corresponds to a different addressing mode. Each
/// column corresponds to a different register size.
///
/// \attention Rows must be structured as follows:
/// - Row 0: The ri opcode variants
/// - Row 1: The rs opcode variants
/// - Row 2: The rr opcode variants
/// - Row 3: The ri opcode variants for negative immediates
/// - Row 4: The rx opcode variants
///
/// \attention Columns must be structured as follows:
/// - Column 0: The 64-bit opcode variants
/// - Column 1: The 32-bit opcode variants
///
/// \p Dst is the destination register of the binop to emit.
/// \p LHS is the left-hand operand of the binop to emit.
/// \p RHS is the right-hand operand of the binop to emit.
MachineInstr *emitAddSub(
const std::array<std::array<unsigned, 2>, 5> &AddrModeAndSizeToOpcode,
Register Dst, MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitADD(Register DefReg, MachineOperand &LHS,
MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitADDS(Register Dst, MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitSUBS(Register Dst, MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitCMN(MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitTST(MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitSelect(Register Dst, Register LHS, Register RHS,
AArch64CC::CondCode CC,
MachineIRBuilder &MIRBuilder) const;
MachineInstr *emitExtractVectorElt(Optional<Register> DstReg,
const RegisterBank &DstRB, LLT ScalarTy,
Register VecReg, unsigned LaneIdx,
MachineIRBuilder &MIRBuilder) const;
/// Emit a CSet for an integer compare.
///
/// \p DefReg and \p SrcReg are expected to be 32-bit scalar registers.
MachineInstr *emitCSetForICMP(Register DefReg, unsigned Pred,
MachineIRBuilder &MIRBuilder,
Register SrcReg = AArch64::WZR) const;
/// Emit a CSet for a FP compare.
///
/// \p Dst is expected to be a 32-bit scalar register.
MachineInstr *emitCSetForFCmp(Register Dst, CmpInst::Predicate Pred,
MachineIRBuilder &MIRBuilder) const;
/// Emit the overflow op for \p Opcode.
///
/// \p Opcode is expected to be an overflow op's opcode, e.g. G_UADDO,
/// G_USUBO, etc.
std::pair<MachineInstr *, AArch64CC::CondCode>
emitOverflowOp(unsigned Opcode, Register Dst, MachineOperand &LHS,
MachineOperand &RHS, MachineIRBuilder &MIRBuilder) const;
/// Emit a TB(N)Z instruction which tests \p Bit in \p TestReg.
/// \p IsNegative is true if the test should be "not zero".
/// This will also optimize the test bit instruction when possible.
MachineInstr *emitTestBit(Register TestReg, uint64_t Bit, bool IsNegative,
MachineBasicBlock *DstMBB,
MachineIRBuilder &MIB) const;
/// Emit a CB(N)Z instruction which branches to \p DestMBB.
MachineInstr *emitCBZ(Register CompareReg, bool IsNegative,
MachineBasicBlock *DestMBB,
MachineIRBuilder &MIB) 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);
}
/// Helper to try to fold in a GISEL_ADD_LOW into an immediate, to be used
/// from complex pattern matchers like selectAddrModeIndexed().
ComplexRendererFns tryFoldAddLowIntoImm(MachineInstr &RootDef, unsigned Size,
MachineRegisterInfo &MRI) const;
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;
/// Move \p Reg to \p RC if \p Reg is not already on \p RC.
///
/// \returns Either \p Reg if no change was necessary, or the new register
/// created by moving \p Reg.
///
/// Note: This uses emitCopy right now.
Register moveScalarRegClass(Register Reg, const TargetRegisterClass &RC,
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;
void renderFPImm16(MachineInstrBuilder &MIB, const MachineInstr &MI,
int OpIdx = -1) const;
void renderFPImm32(MachineInstrBuilder &MIB, const MachineInstr &MI,
int OpIdx = -1) const;
void renderFPImm64(MachineInstrBuilder &MIB, const MachineInstr &MI,
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 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;
// Some cached values used during selection.
// We use LR as a live-in register, and we keep track of it here as it can be
// clobbered by calls.
Register MFReturnAddr;
#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;
}
/// Returns the minimum size the given register bank can hold.
static unsigned getMinSizeForRegBank(const RegisterBank &RB) {
switch (RB.getID()) {
case AArch64::GPRRegBankID:
return 32;
case AArch64::FPRRegBankID:
return 8;
default:
llvm_unreachable("Tried to get minimum size for unknown register bank.");
}
}
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.getSExtValue();
} else
return None;
return Immed;
}
/// 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 SrcReg
/// to \p *To.
///
/// E.g "To = COPY SrcReg:SubReg"
static bool copySubReg(MachineInstr &I, MachineRegisterInfo &MRI,
const RegisterBankInfo &RBI, Register SrcReg,
const TargetRegisterClass *To, unsigned SubReg) {
assert(SrcReg.isValid() && "Expected a valid source register?");
assert(To && "Destination register class cannot be null");
assert(SubReg && "Expected a valid subregister");
MachineIRBuilder MIB(I);
auto SubRegCopy =
MIB.buildInstr(TargetOpcode::COPY, {To}, {}).addReg(SrcReg, 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!");
bool ValidCopy = true;
#ifndef NDEBUG
ValidCopy = KnownValid || isValidCopy(I, DstRegBank, MRI, TRI, RBI);
assert(ValidCopy && "Invalid copy.");
#endif
(void)KnownValid;
return ValidCopy;
};
// Is this a copy? If so, then we may need to insert a subregister copy.
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);
unsigned SubReg;
// If the source bank doesn't support a subregister copy small enough,
// then we first need to copy to the destination bank.
if (getMinSizeForRegBank(SrcRegBank) > DstSize) {
const TargetRegisterClass *DstTempRC =
getMinClassForRegBank(DstRegBank, SrcSize, /* GetAllRegSet */ true);
getSubRegForClass(DstRC, TRI, SubReg);
MachineIRBuilder MIB(I);
auto Copy = MIB.buildCopy({DstTempRC}, {SrcReg});
copySubReg(I, MRI, RBI, Copy.getReg(0), DstRC, SubReg);
} else if (SrcSize > DstSize) {
// If the source register is bigger than the destination we need to
// perform a subregister copy.
const TargetRegisterClass *SubRegRC =
getMinClassForRegBank(SrcRegBank, DstSize, /* GetAllRegSet */ true);
getSubRegForClass(SubRegRC, TRI, SubReg);
copySubReg(I, MRI, RBI, SrcReg, DstRC, SubReg);
} else if (DstSize > SrcSize) {
// If the destination register is bigger than the source we need to do
// a promotion using SUBREG_TO_REG.
const TargetRegisterClass *PromotionRC =
getMinClassForRegBank(SrcRegBank, DstSize, /* GetAllRegSet */ true);
getSubRegForClass(SrcRC, TRI, SubReg);
Register PromoteReg = MRI.createVirtualRegister(PromotionRC);
BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(AArch64::SUBREG_TO_REG), PromoteReg)
.addImm(0)
.addUse(SrcReg)
.addImm(SubReg);
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;
}
MachineInstr *
AArch64InstructionSelector::emitSelect(Register Dst, Register True,
Register False, AArch64CC::CondCode CC,
MachineIRBuilder &MIB) const {
MachineRegisterInfo &MRI = *MIB.getMRI();
assert(RBI.getRegBank(False, MRI, TRI)->getID() ==
RBI.getRegBank(True, MRI, TRI)->getID() &&
"Expected both select operands to have the same regbank?");
LLT Ty = MRI.getType(True);
if (Ty.isVector())
return nullptr;
const unsigned Size = Ty.getSizeInBits();
assert((Size == 32 || Size == 64) &&
"Expected 32 bit or 64 bit select only?");
const bool Is32Bit = Size == 32;
if (RBI.getRegBank(True, MRI, TRI)->getID() != AArch64::GPRRegBankID) {
unsigned Opc = Is32Bit ? AArch64::FCSELSrrr : AArch64::FCSELDrrr;
auto FCSel = MIB.buildInstr(Opc, {Dst}, {True, False}).addImm(CC);
constrainSelectedInstRegOperands(*FCSel, TII, TRI, RBI);
return &*FCSel;
}
// By default, we'll try and emit a CSEL.
unsigned Opc = Is32Bit ? AArch64::CSELWr : AArch64::CSELXr;
bool Optimized = false;
auto TryFoldBinOpIntoSelect = [&Opc, Is32Bit, &CC, &MRI,
&Optimized](Register &Reg, Register &OtherReg,
bool Invert) {
if (Optimized)
return false;
// Attempt to fold:
//
// %sub = G_SUB 0, %x
// %select = G_SELECT cc, %reg, %sub
//
// Into:
// %select = CSNEG %reg, %x, cc
Register MatchReg;
if (mi_match(Reg, MRI, m_Neg(m_Reg(MatchReg)))) {
Opc = Is32Bit ? AArch64::CSNEGWr : AArch64::CSNEGXr;
Reg = MatchReg;
if (Invert) {
CC = AArch64CC::getInvertedCondCode(CC);
std::swap(Reg, OtherReg);
}
return true;
}
// Attempt to fold:
//
// %xor = G_XOR %x, -1
// %select = G_SELECT cc, %reg, %xor
//
// Into:
// %select = CSINV %reg, %x, cc
if (mi_match(Reg, MRI, m_Not(m_Reg(MatchReg)))) {
Opc = Is32Bit ? AArch64::CSINVWr : AArch64::CSINVXr;
Reg = MatchReg;
if (Invert) {
CC = AArch64CC::getInvertedCondCode(CC);
std::swap(Reg, OtherReg);
}
return true;
}
// Attempt to fold:
//
// %add = G_ADD %x, 1
// %select = G_SELECT cc, %reg, %add
//
// Into:
// %select = CSINC %reg, %x, cc
if (mi_match(Reg, MRI,
m_any_of(m_GAdd(m_Reg(MatchReg), m_SpecificICst(1)),
m_GPtrAdd(m_Reg(MatchReg), m_SpecificICst(1))))) {
Opc = Is32Bit ? AArch64::CSINCWr : AArch64::CSINCXr;
Reg = MatchReg;
if (Invert) {
CC = AArch64CC::getInvertedCondCode(CC);
std::swap(Reg, OtherReg);
}
return true;
}
return false;
};
// Helper lambda which tries to use CSINC/CSINV for the instruction when its
// true/false values are constants.
// FIXME: All of these patterns already exist in tablegen. We should be
// able to import these.
auto TryOptSelectCst = [&Opc, &True, &False, &CC, Is32Bit, &MRI,
&Optimized]() {
if (Optimized)
return false;
auto TrueCst = getConstantVRegValWithLookThrough(True, MRI);
auto FalseCst = getConstantVRegValWithLookThrough(False, MRI);
if (!TrueCst && !FalseCst)
return false;
Register ZReg = Is32Bit ? AArch64::WZR : AArch64::XZR;
if (TrueCst && FalseCst) {
int64_t T = TrueCst->Value.getSExtValue();
int64_t F = FalseCst->Value.getSExtValue();
if (T == 0 && F == 1) {
// G_SELECT cc, 0, 1 -> CSINC zreg, zreg, cc
Opc = Is32Bit ? AArch64::CSINCWr : AArch64::CSINCXr;
True = ZReg;
False = ZReg;
return true;
}
if (T == 0 && F == -1) {
// G_SELECT cc 0, -1 -> CSINV zreg, zreg cc
Opc = Is32Bit ? AArch64::CSINVWr : AArch64::CSINVXr;
True = ZReg;
False = ZReg;
return true;
}
}
if (TrueCst) {
int64_t T = TrueCst->Value.getSExtValue();
if (T == 1) {
// G_SELECT cc, 1, f -> CSINC f, zreg, inv_cc
Opc = Is32Bit ? AArch64::CSINCWr : AArch64::CSINCXr;
True = False;
False = ZReg;
CC = AArch64CC::getInvertedCondCode(CC);
return true;
}
if (T == -1) {
// G_SELECT cc, -1, f -> CSINV f, zreg, inv_cc
Opc = Is32Bit ? AArch64::CSINVWr : AArch64::CSINVXr;
True = False;
False = ZReg;
CC = AArch64CC::getInvertedCondCode(CC);
return true;
}
}
if (FalseCst) {
int64_t F = FalseCst->Value.getSExtValue();
if (F == 1) {
// G_SELECT cc, t, 1 -> CSINC t, zreg, cc
Opc = Is32Bit ? AArch64::CSINCWr : AArch64::CSINCXr;
False = ZReg;
return true;
}
if (F == -1) {
// G_SELECT cc, t, -1 -> CSINC t, zreg, cc
Opc = Is32Bit ? AArch64::CSINVWr : AArch64::CSINVXr;
False = ZReg;
return true;
}
}
return false;
};
Optimized |= TryFoldBinOpIntoSelect(False, True, /*Invert = */ false);
Optimized |= TryFoldBinOpIntoSelect(True, False, /*Invert = */ true);
Optimized |= TryOptSelectCst();
auto SelectInst = MIB.buildInstr(Opc, {Dst}, {True, False}).addImm(CC);
constrainSelectedInstRegOperands(*SelectInst, TII, TRI, RBI);
return &*SelectInst;
}
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;
}
}
/// Return a register which can be used as a bit to test in a TB(N)Z.
static Register getTestBitReg(Register Reg, uint64_t &Bit, bool &Invert,
MachineRegisterInfo &MRI) {
assert(Reg.isValid() && "Expected valid register!");
while (MachineInstr *MI = getDefIgnoringCopies(Reg, MRI)) {
unsigned Opc = MI->getOpcode();
if (!MI->getOperand(0).isReg() ||
!MRI.hasOneNonDBGUse(MI->getOperand(0).getReg()))
break;
// (tbz (any_ext x), b) -> (tbz x, b) if we don't use the extended bits.
//
// (tbz (trunc x), b) -> (tbz x, b) is always safe, because the bit number
// on the truncated x is the same as the bit number on x.
if (Opc == TargetOpcode::G_ANYEXT || Opc == TargetOpcode::G_ZEXT ||
Opc == TargetOpcode::G_TRUNC) {
Register NextReg = MI->getOperand(1).getReg();
// Did we find something worth folding?
if (!NextReg.isValid() || !MRI.hasOneNonDBGUse(NextReg))
break;
// NextReg is worth folding. Keep looking.
Reg = NextReg;
continue;
}
// Attempt to find a suitable operation with a constant on one side.
Optional<uint64_t> C;
Register TestReg;
switch (Opc) {
default:
break;
case TargetOpcode::G_AND:
case TargetOpcode::G_XOR: {
TestReg = MI->getOperand(1).getReg();
Register ConstantReg = MI->getOperand(2).getReg();
auto VRegAndVal = getConstantVRegValWithLookThrough(ConstantReg, MRI);
if (!VRegAndVal) {
// AND commutes, check the other side for a constant.
// FIXME: Can we canonicalize the constant so that it's always on the
// same side at some point earlier?
std::swap(ConstantReg, TestReg);
VRegAndVal = getConstantVRegValWithLookThrough(ConstantReg, MRI);
}
if (VRegAndVal)
C = VRegAndVal->Value.getSExtValue();
break;
}
case TargetOpcode::G_ASHR:
case TargetOpcode::G_LSHR:
case TargetOpcode::G_SHL: {
TestReg = MI->getOperand(1).getReg();
auto VRegAndVal =
getConstantVRegValWithLookThrough(MI->getOperand(2).getReg(), MRI);
if (VRegAndVal)
C = VRegAndVal->Value.getSExtValue();
break;
}
}
// Didn't find a constant or viable register. Bail out of the loop.
if (!C || !TestReg.isValid())
break;
// We found a suitable instruction with a constant. Check to see if we can
// walk through the instruction.
Register NextReg;
unsigned TestRegSize = MRI.getType(TestReg).getSizeInBits();
switch (Opc) {
default:
break;
case TargetOpcode::G_AND:
// (tbz (and x, m), b) -> (tbz x, b) when the b-th bit of m is set.
if ((*C >> Bit) & 1)
NextReg = TestReg;
break;
case TargetOpcode::G_SHL:
// (tbz (shl x, c), b) -> (tbz x, b-c) when b-c is positive and fits in
// the type of the register.
if (*C <= Bit && (Bit - *C) < TestRegSize) {
NextReg = TestReg;
Bit = Bit - *C;
}
break;
case TargetOpcode::G_ASHR:
// (tbz (ashr x, c), b) -> (tbz x, b+c) or (tbz x, msb) if b+c is > # bits
// in x
NextReg = TestReg;
Bit = Bit + *C;
if (Bit >= TestRegSize)
Bit = TestRegSize - 1;
break;
case TargetOpcode::G_LSHR:
// (tbz (lshr x, c), b) -> (tbz x, b+c) when b + c is < # bits in x
if ((Bit + *C) < TestRegSize) {
NextReg = TestReg;
Bit = Bit + *C;
}
break;
case TargetOpcode::G_XOR:
// We can walk through a G_XOR by inverting whether we use tbz/tbnz when
// appropriate.
//
// e.g. If x' = xor x, c, and the b-th bit is set in c then
//
// tbz x', b -> tbnz x, b
//
// Because x' only has the b-th bit set if x does not.
if ((*C >> Bit) & 1)
Invert = !Invert;
NextReg = TestReg;
break;
}
// Check if we found anything worth folding.
if (!NextReg.isValid())
return Reg;
Reg = NextReg;
}
return Reg;
}
MachineInstr *AArch64InstructionSelector::emitTestBit(
Register TestReg, uint64_t Bit, bool IsNegative, MachineBasicBlock *DstMBB,
MachineIRBuilder &MIB) const {
assert(TestReg.isValid());
assert(ProduceNonFlagSettingCondBr &&
"Cannot emit TB(N)Z with speculation tracking!");
MachineRegisterInfo &MRI = *MIB.getMRI();
// Attempt to optimize the test bit by walking over instructions.
TestReg = getTestBitReg(TestReg, Bit, IsNegative, MRI);
LLT Ty = MRI.getType(TestReg);
unsigned Size = Ty.getSizeInBits();
assert(!Ty.isVector() && "Expected a scalar!");
assert(Bit < 64 && "Bit is too large!");
// When the test register is a 64-bit register, we have to narrow to make
// TBNZW work.
bool UseWReg = Bit < 32;
unsigned NecessarySize = UseWReg ? 32 : 64;
if (Size != NecessarySize)
TestReg = moveScalarRegClass(
TestReg, UseWReg ? AArch64::GPR32RegClass : AArch64::GPR64RegClass,
MIB);
static const unsigned OpcTable[2][2] = {{AArch64::TBZX, AArch64::TBNZX},
{AArch64::TBZW, AArch64::TBNZW}};
unsigned Opc = OpcTable[UseWReg][IsNegative];
auto TestBitMI =
MIB.buildInstr(Opc).addReg(TestReg).addImm(Bit).addMBB(DstMBB);
constrainSelectedInstRegOperands(*TestBitMI, TII, TRI, RBI);
return &*TestBitMI;
}
bool AArch64InstructionSelector::tryOptAndIntoCompareBranch(
MachineInstr &AndInst, bool Invert, MachineBasicBlock *DstMBB,
MachineIRBuilder &MIB) const {
assert(AndInst.getOpcode() == TargetOpcode::G_AND && "Expected G_AND only?");
// Given something like this:
//
// %x = ...Something...
// %one = G_CONSTANT i64 1
// %zero = G_CONSTANT i64 0
// %and = G_AND %x, %one
// %cmp = G_ICMP intpred(ne), %and, %zero
// %cmp_trunc = G_TRUNC %cmp
// G_BRCOND %cmp_trunc, %bb.3
//
// We want to try and fold the AND into the G_BRCOND and produce either a
// TBNZ (when we have intpred(ne)) or a TBZ (when we have intpred(eq)).
//
// In this case, we'd get
//
// TBNZ %x %bb.3
//
// Check if the AND has a constant on its RHS which we can use as a mask.
// If it's a power of 2, then it's the same as checking a specific bit.
// (e.g, ANDing with 8 == ANDing with 000...100 == testing if bit 3 is set)
auto MaybeBit = getConstantVRegValWithLookThrough(
AndInst.getOperand(2).getReg(), *MIB.getMRI());
if (!MaybeBit)
return false;
int32_t Bit = MaybeBit->Value.exactLogBase2();
if (Bit < 0)
return false;
Register TestReg = AndInst.getOperand(1).getReg();
// Emit a TB(N)Z.
emitTestBit(TestReg, Bit, Invert, DstMBB, MIB);
return true;
}
MachineInstr *AArch64InstructionSelector::emitCBZ(Register CompareReg,
bool IsNegative,
MachineBasicBlock *DestMBB,
MachineIRBuilder &MIB) const {
assert(ProduceNonFlagSettingCondBr && "CBZ does not set flags!");
MachineRegisterInfo &MRI = *MIB.getMRI();
assert(RBI.getRegBank(CompareReg, MRI, TRI)->getID() ==
AArch64::GPRRegBankID &&
"Expected GPRs only?");
auto Ty = MRI.getType(CompareReg);
unsigned Width = Ty.getSizeInBits();
assert(!Ty.isVector() && "Expected scalar only?");
assert(Width <= 64 && "Expected width to be at most 64?");
static const unsigned OpcTable[2][2] = {{AArch64::CBZW, AArch64::CBZX},
{AArch64::CBNZW, AArch64::CBNZX}};
unsigned Opc = OpcTable[IsNegative][Width == 64];
auto BranchMI = MIB.buildInstr(Opc, {}, {CompareReg}).addMBB(DestMBB);
constrainSelectedInstRegOperands(*BranchMI, TII, TRI, RBI);
return &*BranchMI;
}
bool AArch64InstructionSelector::selectCompareBranchFedByFCmp(
MachineInstr &I, MachineInstr &FCmp, MachineIRBuilder &MIB) const {
assert(FCmp.getOpcode() == TargetOpcode::G_FCMP);
assert(I.getOpcode() == TargetOpcode::G_BRCOND);
// Unfortunately, the mapping of LLVM FP CC's onto AArch64 CC's isn't
// totally clean. Some of them require two branches to implement.
auto Pred = (CmpInst::Predicate)FCmp.getOperand(1).getPredicate();
emitFPCompare(FCmp.getOperand(2).getReg(), FCmp.getOperand(3).getReg(), MIB,
Pred);
AArch64CC::CondCode CC1, CC2;
changeFCMPPredToAArch64CC(static_cast<CmpInst::Predicate>(Pred), CC1, CC2);
MachineBasicBlock *DestMBB = I.getOperand(1).getMBB();
MIB.buildInstr(AArch64::Bcc, {}, {}).addImm(CC1).addMBB(DestMBB);
if (CC2 != AArch64CC::AL)
MIB.buildInstr(AArch64::Bcc, {}, {}).addImm(CC2).addMBB(DestMBB);
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::tryOptCompareBranchFedByICmp(
MachineInstr &I, MachineInstr &ICmp, MachineIRBuilder &MIB) const {
assert(ICmp.getOpcode() == TargetOpcode::G_ICMP);
assert(I.getOpcode() == TargetOpcode::G_BRCOND);
// Attempt to optimize the G_BRCOND + G_ICMP into a TB(N)Z/CB(N)Z.
//
// 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.
if (!ProduceNonFlagSettingCondBr)
return false;
MachineRegisterInfo &MRI = *MIB.getMRI();
MachineBasicBlock *DestMBB = I.getOperand(1).getMBB();
auto Pred =
static_cast<CmpInst::Predicate>(ICmp.getOperand(1).getPredicate());
Register LHS = ICmp.getOperand(2).getReg();
Register RHS = ICmp.getOperand(3).getReg();
// We're allowed to emit a TB(N)Z/CB(N)Z. Try to do that.
auto VRegAndVal = getConstantVRegValWithLookThrough(RHS, MRI);
MachineInstr *AndInst = getOpcodeDef(TargetOpcode::G_AND, LHS, MRI);
// When we can emit a TB(N)Z, prefer that.
//
// Handle non-commutative condition codes first.
// Note that we don't want to do this when we have a G_AND because it can
// become a tst. The tst will make the test bit in the TB(N)Z redundant.
if (VRegAndVal && !AndInst) {
int64_t C = VRegAndVal->Value.getSExtValue();
// When we have a greater-than comparison, we can just test if the msb is
// zero.
if (C == -1 && Pred == CmpInst::ICMP_SGT) {
uint64_t Bit = MRI.getType(LHS).getSizeInBits() - 1;
emitTestBit(LHS, Bit, /*IsNegative = */ false, DestMBB, MIB);
I.eraseFromParent();
return true;
}
// When we have a less than comparison, we can just test if the msb is not
// zero.
if (C == 0 && Pred == CmpInst::ICMP_SLT) {
uint64_t Bit = MRI.getType(LHS).getSizeInBits() - 1;
emitTestBit(LHS, Bit, /*IsNegative = */ true, DestMBB, MIB);
I.eraseFromParent();
return true;
}
}
// Attempt to handle commutative condition codes. Right now, that's only
// eq/ne.
if (ICmpInst::isEquality(Pred)) {
if (!VRegAndVal) {
std::swap(RHS, LHS);
VRegAndVal = getConstantVRegValWithLookThrough(RHS, MRI);
AndInst = getOpcodeDef(TargetOpcode::G_AND, LHS, MRI);
}
if (VRegAndVal && VRegAndVal->Value == 0) {
// If there's a G_AND feeding into this branch, try to fold it away by
// emitting a TB(N)Z instead.
//
// Note: If we have LT, then it *is* possible to fold, but it wouldn't be
// beneficial. When we have an AND and LT, we need a TST/ANDS, so folding
// would be redundant.
if (AndInst &&
tryOptAndIntoCompareBranch(
*AndInst, /*Invert = */ Pred == CmpInst::ICMP_NE, DestMBB, MIB)) {
I.eraseFromParent();
return true;
}
// Otherwise, try to emit a CB(N)Z instead.
auto LHSTy = MRI.getType(LHS);
if (!LHSTy.isVector() && LHSTy.getSizeInBits() <= 64) {
emitCBZ(LHS, /*IsNegative = */ Pred == CmpInst::ICMP_NE, DestMBB, MIB);
I.eraseFromParent();
return true;
}
}
}
return false;
}
bool AArch64InstructionSelector::selectCompareBranchFedByICmp(
MachineInstr &I, MachineInstr &ICmp, MachineIRBuilder &MIB) const {
assert(ICmp.getOpcode() == TargetOpcode::G_ICMP);
assert(I.getOpcode() == TargetOpcode::G_BRCOND);
if (tryOptCompareBranchFedByICmp(I, ICmp, MIB))
return true;
// Couldn't optimize. Emit a compare + a Bcc.
MachineBasicBlock *DestMBB = I.getOperand(1).getMBB();
auto PredOp = ICmp.getOperand(1);
emitIntegerCompare(ICmp.getOperand(2), ICmp.getOperand(3), PredOp, MIB);
const AArch64CC::CondCode CC = changeICMPPredToAArch64CC(
static_cast<CmpInst::Predicate>(PredOp.getPredicate()));
MIB.buildInstr(AArch64::Bcc, {}, {}).addImm(CC).addMBB(DestMBB);
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectCompareBranch(
MachineInstr &I, MachineFunction &MF, MachineRegisterInfo &MRI) const {
Register CondReg = I.getOperand(0).getReg();
MachineInstr *CCMI = MRI.getVRegDef(CondReg);
if (CCMI->getOpcode() == TargetOpcode::G_TRUNC) {
CondReg = CCMI->getOperand(1).getReg();
CCMI = MRI.getVRegDef(CondReg);
}
// Try to select the G_BRCOND using whatever is feeding the condition if
// possible.
MachineIRBuilder MIB(I);
unsigned CCMIOpc = CCMI->getOpcode();
if (CCMIOpc == TargetOpcode::G_FCMP)
return selectCompareBranchFedByFCmp(I, *CCMI, MIB);
if (CCMIOpc == TargetOpcode::G_ICMP)
return selectCompareBranchFedByICmp(I, *CCMI, MIB);
// 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.
if (ProduceNonFlagSettingCondBr) {
emitTestBit(CondReg, /*Bit = */ 0, /*IsNegative = */ true,
I.getOperand(1).getMBB(), MIB);
I.eraseFromParent();
return true;
}
// Can't emit TB(N)Z/CB(N)Z. Emit a tst + bcc instead.
auto TstMI =
MIB.buildInstr(AArch64::ANDSWri, {LLT::scalar(32)}, {CondReg}).addImm(1);
constrainSelectedInstRegOperands(*TstMI, TII, TRI, RBI);
auto Bcc = MIB.buildInstr(AArch64::Bcc)
.addImm(AArch64CC::EQ)
.addMBB(I.getOperand(1).getMBB());
I.eraseFromParent();
return constrainSelectedInstRegOperands(*Bcc, TII, TRI, RBI);
}
/// 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");
return getAArch64VectorSplatScalar(*OpMI, MRI);
}
/// 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 if (Ty == LLT::vector(4, 16)) {
Opc = ImmVal ? AArch64::SHLv4i16_shift : AArch64::USHLv4i16;
} else if (Ty == LLT::vector(8, 16)) {
Opc = ImmVal ? AArch64::SHLv8i16_shift : AArch64::USHLv8i16;
} else if (Ty == LLT::vector(16, 8)) {
Opc = ImmVal ? AArch64::SHLv16i8_shift : AArch64::USHLv16i8;
} else if (Ty == LLT::vector(8, 8)) {
Opc = ImmVal ? AArch64::SHLv8i8_shift : AArch64::USHLv8i8;
} 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::selectVectorAshrLshr(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_ASHR ||
I.getOpcode() == TargetOpcode::G_LSHR);
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;
bool IsASHR = I.getOpcode() == TargetOpcode::G_ASHR;
// We expect the immediate case to be lowered in the PostLegalCombiner to
// AArch64ISD::VASHR or AArch64ISD::VLSHR equivalents.
// 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 =
getRegClassForTypeOnBank(Ty, RBI.getRegBank(AArch64::FPRRegBankID), RBI);
if (Ty == LLT::vector(2, 64)) {
Opc = IsASHR ? AArch64::SSHLv2i64 : AArch64::USHLv2i64;
NegOpc = AArch64::NEGv2i64;
} else if (Ty == LLT::vector(4, 32)) {
Opc = IsASHR ? AArch64::SSHLv4i32 : AArch64::USHLv4i32;
NegOpc = AArch64::NEGv4i32;
} else if (Ty == LLT::vector(2, 32)) {
Opc = IsASHR ? AArch64::SSHLv2i32 : AArch64::USHLv2i32;
NegOpc = AArch64::NEGv2i32;
} else if (Ty == LLT::vector(4, 16)) {
Opc = IsASHR ? AArch64::SSHLv4i16 : AArch64::USHLv4i16;
NegOpc = AArch64::NEGv4i16;
} else if (Ty == LLT::vector(8, 16)) {
Opc = IsASHR ? AArch64::SSHLv8i16 : AArch64::USHLv8i16;
NegOpc = AArch64::NEGv8i16;
} else if (Ty == LLT::vector(16, 8)) {
Opc = IsASHR ? AArch64::SSHLv16i8 : AArch64::USHLv16i8;
NegOpc = AArch64::NEGv16i8;
} else if (Ty == LLT::vector(8, 8)) {
Opc = IsASHR ? AArch64::SSHLv8i8 : AArch64::USHLv8i8;
NegOpc = AArch64::NEGv8i8;
} 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());
}
bool AArch64InstructionSelector::preISelLower(MachineInstr &I) {
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 false;
assert(!ShiftTy.isVector() && "unexpected vector shift ty");
if (SrcTy.getSizeInBits() != 32 || ShiftTy.getSizeInBits() != 64)
return false;
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 true;
}
case TargetOpcode::G_STORE: {
bool Changed = contractCrossBankCopyIntoStore(I, MRI);
MachineOperand &SrcOp = I.getOperand(0);
if (MRI.getType(SrcOp.getReg()).isPointer()) {
// Allow matching with imported patterns for stores of pointers. Unlike
// G_LOAD/G_PTR_ADD, we may not have selected all users. So, emit a copy
// and constrain.
MachineIRBuilder MIB(I);
auto Copy = MIB.buildCopy(LLT::scalar(64), SrcOp);
Register NewSrc = Copy.getReg(0);
SrcOp.setReg(NewSrc);
RBI.constrainGenericRegister(NewSrc, AArch64::GPR64RegClass, MRI);
Changed = true;
}
return Changed;
}
case TargetOpcode::G_PTR_ADD:
return convertPtrAddToAdd(I, MRI);
case TargetOpcode::G_LOAD: {
// For scalar loads of pointers, we try to convert the dest type from p0
// to s64 so that our imported patterns can match. Like with the G_PTR_ADD
// conversion, this should be ok because all users should have been
// selected already, so the type doesn't matter for them.
Register DstReg = I.getOperand(0).getReg();
const LLT DstTy = MRI.getType(DstReg);
if (!DstTy.isPointer())
return false;
MRI.setType(DstReg, LLT::scalar(64));
return true;
}
case AArch64::G_DUP: {
// Convert the type from p0 to s64 to help selection.
LLT DstTy = MRI.getType(I.getOperand(0).getReg());
if (!DstTy.getElementType().isPointer())
return false;
MachineIRBuilder MIB(I);
auto NewSrc = MIB.buildCopy(LLT::scalar(64), I.getOperand(1).getReg());
MRI.setType(I.getOperand(0).getReg(),
DstTy.changeElementType(LLT::scalar(64)));
MRI.setRegClass(NewSrc.getReg(0), &AArch64::GPR64RegClass);
I.getOperand(1).setReg(NewSrc.getReg(0));
return true;
}
case TargetOpcode::G_UITOFP:
case TargetOpcode::G_SITOFP: {
// If both source and destination regbanks are FPR, then convert the opcode
// to G_SITOF so that the importer can select it to an fpr variant.
// Otherwise, it ends up matching an fpr/gpr variant and adding a cross-bank
// copy.
Register SrcReg = I.getOperand(1).getReg();
LLT SrcTy = MRI.getType(SrcReg);
LLT DstTy = MRI.getType(I.getOperand(0).getReg());
if (SrcTy.isVector() || SrcTy.getSizeInBits() != DstTy.getSizeInBits())
return false;
if (RBI.getRegBank(SrcReg, MRI, TRI)->getID() == AArch64::FPRRegBankID) {
if (I.getOpcode() == TargetOpcode::G_SITOFP)
I.setDesc(TII.get(AArch64::G_SITOF));
else
I.setDesc(TII.get(AArch64::G_UITOF));
return true;
}
return false;
}
default:
return false;
}
}
/// This lowering tries to look for G_PTR_ADD instructions and then converts
/// them to a standard G_ADD with a COPY on the source.
///
/// The motivation behind this is to expose the add semantics to the imported
/// tablegen patterns. We shouldn't need to check for uses being loads/stores,
/// because the selector works bottom up, uses before defs. By the time we
/// end up trying to select a G_PTR_ADD, we should have already attempted to
/// fold this into addressing modes and were therefore unsuccessful.
bool AArch64InstructionSelector::convertPtrAddToAdd(
MachineInstr &I, MachineRegisterInfo &MRI) {
assert(I.getOpcode() == TargetOpcode::G_PTR_ADD && "Expected G_PTR_ADD");
Register DstReg = I.getOperand(0).getReg();
Register AddOp1Reg = I.getOperand(1).getReg();
const LLT PtrTy = MRI.getType(DstReg);
if (PtrTy.getAddressSpace() != 0)
return false;
MachineIRBuilder MIB(I);
const LLT CastPtrTy = PtrTy.isVector() ? LLT::vector(2, 64) : LLT::scalar(64);
auto PtrToInt = MIB.buildPtrToInt(CastPtrTy, AddOp1Reg);
// Set regbanks on the registers.
if (PtrTy.isVector())
MRI.setRegBank(PtrToInt.getReg(0), RBI.getRegBank(AArch64::FPRRegBankID));
else
MRI.setRegBank(PtrToInt.getReg(0), RBI.getRegBank(AArch64::GPRRegBankID));
// Now turn the %dst(p0) = G_PTR_ADD %base, off into:
// %dst(intty) = G_ADD %intbase, off
I.setDesc(TII.get(TargetOpcode::G_ADD));
MRI.setType(DstReg, CastPtrTy);
I.getOperand(1).setReg(PtrToInt.getReg(0));
if (!select(*PtrToInt)) {
LLVM_DEBUG(dbgs() << "Failed to select G_PTRTOINT in convertPtrAddToAdd");
return false;
}
// Also take the opportunity here to try to do some optimization.
// Try to convert this into a G_SUB if the offset is a 0-x negate idiom.
Register NegatedReg;
if (!mi_match(I.getOperand(2).getReg(), MRI, m_Neg(m_Reg(NegatedReg))))
return true;
I.getOperand(2).setReg(NegatedReg);
I.setDesc(TII.get(TargetOpcode::G_SUB));
return true;
}
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);
}
bool AArch64InstructionSelector::contractCrossBankCopyIntoStore(
MachineInstr &I, MachineRegisterInfo &MRI) {
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.
Register DefDstReg = getSrcRegIgnoringCopies(I.getOperand(0).getReg(), MRI);
if (!DefDstReg.isValid())
return false;
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 false;
// Are the source and dst types the same size?
if (DefDstTy.getSizeInBits() != StoreSrcTy.getSizeInBits())
return false;
if (RBI.getRegBank(StoreSrcReg, MRI, TRI) ==
RBI.getRegBank(DefDstReg, MRI, TRI))
return false;
// We have a cross-bank copy, which is entering a store. Let's fold it.
I.getOperand(0).setReg(DefDstReg);
return true;
}
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 AArch64::G_DUP: {
// Before selecting a DUP instruction, check if it is better selected as a
// MOV or load from a constant pool.
Register Src = I.getOperand(1).getReg();
auto ValAndVReg = getConstantVRegValWithLookThrough(Src, MRI);
if (!ValAndVReg)
return false;
LLVMContext &Ctx = MF.getFunction().getContext();
Register Dst = I.getOperand(0).getReg();
auto *CV = ConstantDataVector::getSplat(
MRI.getType(Dst).getNumElements(),
ConstantInt::get(Type::getIntNTy(Ctx, MRI.getType(Src).getSizeInBits()),
ValAndVReg->Value));
MachineIRBuilder MIRBuilder(I);
if (!emitConstantVector(Dst, CV, MIRBuilder, MRI))
return false;
I.eraseFromParent();
return true;
}
case TargetOpcode::G_BR: {
// If the branch jumps to the fallthrough block, don't bother emitting it.
// Only do this for -O0 for a good code size improvement, because when
// optimizations are enabled we want to leave this choice to
// MachineBlockPlacement.
bool EnableOpt = MF.getTarget().getOptLevel() != CodeGenOpt::None;
if (EnableOpt || !MBB.isLayoutSuccessor(I.getOperand(0).getMBB()))
return false;
I.eraseFromParent();
return true;
}
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.getSizeInBits() == 64) {
I.getOperand(1).ChangeToRegister(AArch64::XZR, false);
RBI.constrainGenericRegister(DefReg, AArch64::GPR64RegClass, MRI);
} else if (Ty.getSizeInBits() == 32) {
I.getOperand(1).ChangeToRegister(AArch64::WZR, false);
RBI.constrainGenericRegister(DefReg, AArch64::GPR32RegClass, MRI);
} else
return false;
I.setDesc(TII.get(TargetOpcode::COPY));
return true;
}
case TargetOpcode::G_ADD: {
// Check if this is being fed by a G_ICMP on either side.
//
// (cmp pred, x, y) + z
//
// In the above case, when the cmp is true, we increment z by 1. So, we can
// fold the add into the cset for the cmp by using cinc.
//
// FIXME: This would probably be a lot nicer in PostLegalizerLowering.
Register X = I.getOperand(1).getReg();
// Only handle scalars. Scalar G_ICMP is only legal for s32, so bail out
// early if we see it.
LLT Ty = MRI.getType(X);
if (Ty.isVector() || Ty.getSizeInBits() != 32)
return false;
Register CmpReg = I.getOperand(2).getReg();
MachineInstr *Cmp = getOpcodeDef(TargetOpcode::G_ICMP, CmpReg, MRI);
if (!Cmp) {
std::swap(X, CmpReg);
Cmp = getOpcodeDef(TargetOpcode::G_ICMP, CmpReg, MRI);
if (!Cmp)
return false;
}
MachineIRBuilder MIRBuilder(I);
auto Pred =
static_cast<CmpInst::Predicate>(Cmp->getOperand(1).getPredicate());
emitIntegerCompare(Cmp->getOperand(2), Cmp->getOperand(3),
Cmp->getOperand(1), MIRBuilder);
emitCSetForICMP(I.getOperand(0).getReg(), Pred, MIRBuilder, X);
I.eraseFromParent();
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();
const AArch64Subtarget *Subtarget =
&static_cast<const AArch64Subtarget &>(MF.getSubtarget());
if (Subtarget->requiresStrictAlign()) {
// We don't support this feature yet.
LLVM_DEBUG(dbgs() << "AArch64 GISel does not support strict-align yet\n");
return false;
}
unsigned Opcode = I.getOpcode();
// G_PHI requires same handling as PHI
if (!I.isPreISelOpcode() || 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.
if (preISelLower(I)) {
Opcode = I.getOpcode(); // The opcode may have been modified, refresh it.
}
// 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_SBFX:
case TargetOpcode::G_UBFX: {
static const unsigned OpcTable[2][2] = {
{AArch64::UBFMWri, AArch64::UBFMXri},
{AArch64::SBFMWri, AArch64::SBFMXri}};
bool IsSigned = Opcode == TargetOpcode::G_SBFX;
unsigned Size = Ty.getSizeInBits();
unsigned Opc = OpcTable[IsSigned][Size == 64];
auto Cst1 =
getConstantVRegValWithLookThrough(I.getOperand(2).getReg(), MRI);
assert(Cst1 && "Should have gotten a constant for src 1?");
auto Cst2 =
getConstantVRegValWithLookThrough(I.getOperand(3).getReg(), MRI);
assert(Cst2 && "Should have gotten a constant for src 2?");
auto LSB = Cst1->Value.getZExtValue();
auto Width = Cst2->Value.getZExtValue();
MachineIRBuilder MIB(I);
auto BitfieldInst =
MIB.buildInstr(Opc, {I.getOperand(0)}, {I.getOperand(1)})
.addImm(LSB)
.addImm(Width);
I.eraseFromParent();
return constrainSelectedInstRegOperands(*BitfieldInst, TII, TRI, RBI);
}
case TargetOpcode::G_BRCOND:
return selectCompareBranch(I, MF, MRI);
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 AArch64::G_ADD_LOW: {
// This op may have been separated from it's ADRP companion by the localizer
// or some other code motion pass. Given that many CPUs will try to
// macro fuse these operations anyway, select this into a MOVaddr pseudo
// which will later be expanded into an ADRP+ADD pair after scheduling.
MachineInstr *BaseMI = MRI.getVRegDef(I.getOperand(1).getReg());
if (BaseMI->getOpcode() != AArch64::ADRP) {
I.setDesc(TII.get(AArch64::ADDXri));
I.addOperand(MachineOperand::CreateImm(0));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
assert(TM.getCodeModel() == CodeModel::Small &&
"Expected small code model");
MachineIRBuilder MIB(I);
auto Op1 = BaseMI->getOperand(1);
auto Op2 = I.getOperand(2);
auto MovAddr = MIB.buildInstr(AArch64::MOVaddr, {I.getOperand(0)}, {})
.addGlobalAddress(Op1.getGlobal(), Op1.getOffset(),
Op1.getTargetFlags())
.addGlobalAddress(Op2.getGlobal(), Op2.getOffset(),
Op2.getTargetFlags());
I.eraseFromParent();
return constrainSelectedInstRegOperands(*MovAddr, TII, TRI, RBI);
}
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 s128 = LLT::scalar(128);
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 && Ty != s128) {
LLVM_DEBUG(dbgs() << "Unable to materialize FP " << Ty
<< " constant, expected: " << s32 << " or " << s64
<< " or " << s128 << '\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.
// 0.0 is not covered by tablegen for FP128. So we will handle this
// scenario in the code here.
if (DefSize != 128 && I.getOperand(1).getFPImm()->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
: (DefSize == 64 ? AArch64::FPR64RegClass
: AArch64::FPR128RegClass);
// For 64b values, emit a constant pool load instead.
// For s32, use a cp load if we have optsize/minsize.
if (DefSize == 64 || DefSize == 128 ||
(DefSize == 32 && shouldOptForSize(&MF))) {
auto *FPImm = I.getOperand(1).getFPImm();
MachineIRBuilder MIB(I);
auto *LoadMI = emitLoadFromConstantPool(FPImm, MIB);
if (!LoadMI) {
LLVM_DEBUG(dbgs() << "Failed to load double constant pool entry\n");
return false;
}
MIB.buildCopy({DefReg}, {LoadMI->getOperand(0).getReg()});
I.eraseFromParent();
return RBI.constrainGenericRegister(DefReg, FPRRC, MRI);
}
// 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();
uint64_t MemSizeInBytes = MemOp.getSize();
if (MemOp.isAtomic()) {
// For now we just support s8 acquire loads to be able to compile stack
// protector code.
if (MemOp.getOrdering() == AtomicOrdering::Acquire &&
MemSizeInBytes == 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 = MemSizeInBytes * 8;
#ifndef NDEBUG
const Register PtrReg = I.getOperand(1).getReg();
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);
// Helper lambda for partially selecting I. Either returns the original
// instruction with an updated opcode, or a new instruction.
auto SelectLoadStoreAddressingMode = [&]() -> MachineInstr * {
bool IsStore = I.getOpcode() == TargetOpcode::G_STORE;
const unsigned NewOpc =
selectLoadStoreUIOp(I.getOpcode(), RB.getID(), MemSizeInBits);
if (NewOpc == I.getOpcode())
return nullptr;
// Check if we can fold anything into the addressing mode.
auto AddrModeFns =
selectAddrModeIndexed(I.getOperand(1), MemSizeInBytes);
if (!AddrModeFns) {
// Can't fold anything. Use the original instruction.
I.setDesc(TII.get(NewOpc));
I.addOperand(MachineOperand::CreateImm(0));
return &I;
}
// Folded something. Create a new instruction and return it.
auto NewInst = MIB.buildInstr(NewOpc, {}, {}, I.getFlags());
IsStore ? NewInst.addUse(ValReg) : NewInst.addDef(ValReg);
NewInst.cloneMemRefs(I);
for (auto &Fn : *AddrModeFns)
Fn(NewInst);
I.eraseFromParent();
return &*NewInst;
};
MachineInstr *LoadStore = SelectLoadStoreAddressingMode();
if (!LoadStore)
return false;
// If we're storing a 0, use WZR/XZR.
if (Opcode == TargetOpcode::G_STORE) {
auto CVal = getConstantVRegValWithLookThrough(
LoadStore->getOperand(0).getReg(), MRI, /*LookThroughInstrs = */ true,
/*HandleFConstants = */ false);
if (CVal && CVal->Value == 0) {
switch (LoadStore->getOpcode()) {
case AArch64::STRWui:
case AArch64::STRHHui:
case AArch64::STRBBui:
LoadStore->getOperand(0).setReg(AArch64::WZR);
break;
case AArch64::STRXui:
LoadStore->getOperand(0).setReg(AArch64::XZR);
break;
}
}
}
if (IsZExtLoad) {
// The zextload from a smaller type to i32 should be handled by the
// importer.
if (MRI.getType(LoadStore->getOperand(0).getReg()).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 = LoadStore->getOperand(0).getReg();
LoadStore->getOperand(0).setReg(LdReg);
MIB.setInsertPt(MIB.getMBB(), std::next(LoadStore->getIterator()));
MIB.buildInstr(AArch64::SUBREG_TO_REG, {DstReg}, {})
.addImm(0)
.addUse(LdReg)
.addImm(AArch64::sub_32);
constrainSelectedInstRegOperands(*LoadStore, TII, TRI, RBI);
return RBI.constrainGenericRegister(DstReg, AArch64::GPR64allRegClass,
MRI);
}
return constrainSelectedInstRegOperands(*LoadStore, 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_LSHR:
case TargetOpcode::G_ASHR:
if (MRI.getType(I.getOperand(0).getReg()).isVector())
return selectVectorAshrLshr(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_FADD:
case TargetOpcode::G_FSUB:
case TargetOpcode::G_FMUL:
case TargetOpcode::G_FDIV:
case TargetOpcode::G_OR: {
// 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_SADDO:
case TargetOpcode::G_UADDO:
case TargetOpcode::G_SSUBO:
case TargetOpcode::G_USUBO: {
// Emit the operation and get the correct condition code.
MachineIRBuilder MIRBuilder(I);
auto OpAndCC = emitOverflowOp(Opcode, I.getOperand(0).getReg(),
I.getOperand(2), I.getOperand(3), MIRBuilder);
// Now, put the overflow result in the register given by the first operand
// to the overflow op. 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.
Register ZReg = AArch64::WZR;
auto CsetMI = MIRBuilder
.buildInstr(AArch64::CSINCWr, {I.getOperand(1).getReg()},
{ZReg, ZReg})
.addImm(getInvertedCondCode(OpAndCC.second));
constrainSelectedInstRegOperands(*CsetMI, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
case TargetOpcode::G_PTRMASK: {
Register MaskReg = I.getOperand(2).getReg();
Optional<int64_t> MaskVal = getConstantVRegSExtVal(MaskReg, MRI);
// TODO: Implement arbitrary cases
if (!MaskVal || !isShiftedMask_64(*MaskVal))
return false;
uint64_t Mask = *MaskVal;
I.setDesc(TII.get(AArch64::ANDXri));
I.getOperand(2).ChangeToImmediate(
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;
}
// We might have a vector G_PTRTOINT, in which case just emit a COPY.
if (Opcode == TargetOpcode::G_PTRTOINT) {
assert(DstTy.isVector() && "Expected an FPR ptrtoint to be a vector");
I.setDesc(TII.get(TargetOpcode::COPY));
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_INREG:
case TargetOpcode::G_SEXT: {
unsigned Opcode = I.getOpcode();
const bool IsSigned = Opcode != TargetOpcode::G_ZEXT;
const Register DefReg = I.getOperand(0).getReg();
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();
// SEXT_INREG has the same src reg size as dst, the size of the value to be
// extended is encoded in the imm.
if (Opcode == TargetOpcode::G_SEXT_INREG)
SrcSize = I.getOperand(2).getImm();
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);
bool IsGPR =
RBI.getRegBank(SrcReg, MRI, TRI)->getID() == AArch64::GPRRegBankID;
if (LoadMI && IsGPR) {
const MachineMemOperand *MemOp = *LoadMI->memoperands_begin();
unsigned BytesLoaded = MemOp->getSize();
if (BytesLoaded < 4 && SrcTy.getSizeInBytes() == BytesLoaded)
return selectCopy(I, TII, MRI, TRI, RBI);
}
// If we are zero extending from 32 bits to 64 bits, it's possible that
// the instruction implicitly does the zero extend for us. In that case,
// we can just emit a SUBREG_TO_REG.
if (IsGPR && SrcSize == 32 && DstSize == 64) {
// Unlike with the G_LOAD case, we don't want to look through copies
// here.
MachineInstr *Def = MRI.getVRegDef(SrcReg);
if (Def && isDef32(*Def)) {
MIB.buildInstr(AArch64::SUBREG_TO_REG, {DefReg}, {})
.addImm(0)
.addUse(SrcReg)
.addImm(AArch64::sub_32);
if (!RBI.constrainGenericRegister(DefReg, AArch64::GPR64RegClass,
MRI)) {
LLVM_DEBUG(dbgs() << "Failed to constrain G_ZEXT destination\n");
return false;
}
if (!RBI.constrainGenericRegister(SrcReg, AArch64::GPR32RegClass,
MRI)) {
LLVM_DEBUG(dbgs() << "Failed to constrain G_ZEXT source\n");
return false;
}
I.eraseFromParent();
return true;
}
}
}
if (DstSize == 64) {
if (Opcode != TargetOpcode::G_SEXT_INREG) {
// 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;
}
SrcReg = MIB.buildInstr(AArch64::SUBREG_TO_REG,
{&AArch64::GPR64RegClass}, {})
.addImm(0)
.addUse(SrcReg)
.addImm(AArch64::sub_32)
.getReg(0);
}
ExtI = MIB.buildInstr(IsSigned ? AArch64::SBFMXri : AArch64::UBFMXri,
{DefReg}, {SrcReg})
.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_FREEZE:
return selectCopy(I, TII, MRI, TRI, RBI);
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;
// Make sure to use an unused vreg instead of wzr, so that the peephole
// optimizations will be able to optimize these.
MachineIRBuilder MIB(I);
Register DeadVReg = MRI.createVirtualRegister(&AArch64::GPR32RegClass);
auto TstMI = MIB.buildInstr(AArch64::ANDSWri, {DeadVReg}, {CondReg})
.addImm(AArch64_AM::encodeLogicalImmediate(1, 32));
constrainSelectedInstRegOperands(*TstMI, TII, TRI, RBI);
if (!emitSelect(I.getOperand(0).getReg(), TReg, FReg, AArch64CC::NE, MIB))
return false;
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);
auto Pred = static_cast<CmpInst::Predicate>(I.getOperand(1).getPredicate());
emitIntegerCompare(I.getOperand(2), I.getOperand(3), I.getOperand(1),
MIRBuilder);
emitCSetForICMP(I.getOperand(0).getReg(), Pred, MIRBuilder);
I.eraseFromParent();
return true;
}
case TargetOpcode::G_FCMP: {
MachineIRBuilder MIRBuilder(I);
CmpInst::Predicate Pred =
static_cast<CmpInst::Predicate>(I.getOperand(1).getPredicate());
if (!emitFPCompare(I.getOperand(2).getReg(), I.getOperand(3).getReg(),
MIRBuilder, Pred) ||
!emitCSetForFCmp(I.getOperand(0).getReg(), Pred, MIRBuilder))
return false;
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 AArch64::G_DUP: {
// When the scalar of G_DUP is an s8/s16 gpr, they can't be selected by
// imported patterns. Do it manually here. Avoiding generating s16 gpr is
// difficult because at RBS we may end up pessimizing the fpr case if we
// decided to add an anyextend to fix this. Manual selection is the most
// robust solution for now.
if (RBI.getRegBank(I.getOperand(1).getReg(), MRI, TRI)->getID() !=
AArch64::GPRRegBankID)
return false; // We expect the fpr regbank case to be imported.
LLT VecTy = MRI.getType(I.getOperand(0).getReg());
if (VecTy == LLT::vector(8, 8))
I.setDesc(TII.get(AArch64::DUPv8i8gpr));
else if (VecTy == LLT::vector(16, 8))
I.setDesc(TII.get(AArch64::DUPv16i8gpr));
else if (VecTy == LLT::vector(4, 16))
I.setDesc(TII.get(AArch64::DUPv4i16gpr));
else if (VecTy == LLT::vector(8, 16))
I.setDesc(TII.get(AArch64::DUPv8i16gpr));
else
return false;
return constrainSelectedInstRegOperands(I, 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);
case TargetOpcode::G_VECREDUCE_FADD:
case TargetOpcode::G_VECREDUCE_ADD:
return selectReduction(I, MRI);
}
return false;
}
bool AArch64InstructionSelector::selectReduction(
MachineInstr &I, MachineRegisterInfo &MRI) const {
Register VecReg = I.getOperand(1).getReg();
LLT VecTy = MRI.getType(VecReg);
if (I.getOpcode() == TargetOpcode::G_VECREDUCE_ADD) {
// For <2 x i32> ADDPv2i32 generates an FPR64 value, so we need to emit
// a subregister copy afterwards.
if (VecTy == LLT::vector(2, 32)) {
MachineIRBuilder MIB(I);
Register DstReg = I.getOperand(0).getReg();
auto AddP = MIB.buildInstr(AArch64::ADDPv2i32, {&AArch64::FPR64RegClass},
{VecReg, VecReg});
auto Copy = MIB.buildInstr(TargetOpcode::COPY, {DstReg}, {})
.addReg(AddP.getReg(0), 0, AArch64::ssub)
.getReg(0);
RBI.constrainGenericRegister(Copy, AArch64::FPR32RegClass, MRI);
I.eraseFromParent();
return constrainSelectedInstRegOperands(*AddP, TII, TRI, RBI);
}
unsigned Opc = 0;
if (VecTy == LLT::vector(16, 8))
Opc = AArch64::ADDVv16i8v;
else if (VecTy == LLT::vector(8, 16))
Opc = AArch64::ADDVv8i16v;
else if (VecTy == LLT::vector(4, 32))
Opc = AArch64::ADDVv4i32v;
else if (VecTy == LLT::vector(2, 64))
Opc = AArch64::ADDPv2i64p;
else {
LLVM_DEBUG(dbgs() << "Unhandled type for add reduction");
return false;
}
I.setDesc(TII.get(Opc));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
if (I.getOpcode() == TargetOpcode::G_VECREDUCE_FADD) {
unsigned Opc = 0;
if (VecTy == LLT::vector(2, 32))
Opc = AArch64::FADDPv2i32p;
else if (VecTy == LLT::vector(2, 64))
Opc = AArch64::FADDPv2i64p;
else {
LLVM_DEBUG(dbgs() << "Unhandled type for fadd reduction");
return false;
}
I.setDesc(TII.get(Opc));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
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);
MF->getInfo<AArch64FunctionInfo>()->setJumpTableEntryInfo(JTI, 4, nullptr);
auto JumpTableInst = MIB.buildInstr(AArch64::JumpTableDest32,
{TargetReg, ScratchReg}, {JTAddr, Index})
.addJumpTableIndex(JTI);
// Build the indirect branch.
MIB.buildInstr(AArch64::BR, {}, {TargetReg});
I.eraseFromParent();
return constrainSelectedInstRegOperands(*JumpTableInst, TII, TRI, RBI);
}
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);
auto LoadGOT =
MIB.buildInstr(AArch64::LOADgot, {&AArch64::GPR64commonRegClass}, {})
.addGlobalAddress(&GV, 0, AArch64II::MO_TLS);
auto Load = MIB.buildInstr(AArch64::LDRXui, {&AArch64::GPR64commonRegClass},
{LoadGOT.getReg(0)})
.addImm(0);
MIB.buildCopy(Register(AArch64::X0), LoadGOT.getReg(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(getBLRCallOpcode(MF), {}, {Load})
.addUse(AArch64::X0, RegState::Implicit)
.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.isVector() && "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.getSExtValue();
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(const Constant *CPVal,
MachineFunction &MF) const {
Type *CPTy = CPVal->getType();
Align Alignment = MF.getDataLayout().getPrefTypeAlign(CPTy);
MachineConstantPool *MCP = MF.getConstantPool();
return MCP->getConstantPoolIndex(CPVal, Alignment);
}
MachineInstr *AArch64InstructionSelector::emitLoadFromConstantPool(
const 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;
case 4:
LoadMI =
&*MIRBuilder
.buildInstr(AArch64::LDRSui, {&AArch64::FPR32RegClass}, {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 == 16) {
Opc = AArch64::INSvi16gpr;
SubregIdx = AArch64::ssub;
} else 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::emitInstr(
unsigned Opcode, std::initializer_list<llvm::DstOp> DstOps,
std::initializer_list<llvm::SrcOp> SrcOps, MachineIRBuilder &MIRBuilder,
const ComplexRendererFns &RenderFns) const {
assert(Opcode && "Expected an opcode?");
assert(!isPreISelGenericOpcode(Opcode) &&
"Function should only be used to produce selected instructions!");
auto MI = MIRBuilder.buildInstr(Opcode, DstOps, SrcOps);
if (RenderFns)
for (auto &Fn : *RenderFns)
Fn(MI);
constrainSelectedInstRegOperands(*MI, TII, TRI, RBI);
return &*MI;
}
MachineInstr *AArch64InstructionSelector::emitAddSub(
const std::array<std::array<unsigned, 2>, 5> &AddrModeAndSizeToOpcode,
Register Dst, MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const {
MachineRegisterInfo &MRI = MIRBuilder.getMF().getRegInfo();
assert(LHS.isReg() && RHS.isReg() && "Expected register operands?");
auto Ty = MRI.getType(LHS.getReg());
assert(!Ty.isVector() && "Expected a scalar or pointer?");
unsigned Size = Ty.getSizeInBits();
assert((Size == 32 || Size == 64) && "Expected a 32-bit or 64-bit type only");
bool Is32Bit = Size == 32;
// INSTRri form with positive arithmetic immediate.
if (auto Fns = selectArithImmed(RHS))
return emitInstr(AddrModeAndSizeToOpcode[0][Is32Bit], {Dst}, {LHS},
MIRBuilder, Fns);
// INSTRri form with negative arithmetic immediate.
if (auto Fns = selectNegArithImmed(RHS))
return emitInstr(AddrModeAndSizeToOpcode[3][Is32Bit], {Dst}, {LHS},
MIRBuilder, Fns);
// INSTRrx form.
if (auto Fns = selectArithExtendedRegister(RHS))
return emitInstr(AddrModeAndSizeToOpcode[4][Is32Bit], {Dst}, {LHS},
MIRBuilder, Fns);
// INSTRrs form.
if (auto Fns = selectShiftedRegister(RHS))
return emitInstr(AddrModeAndSizeToOpcode[1][Is32Bit], {Dst}, {LHS},
MIRBuilder, Fns);
return emitInstr(AddrModeAndSizeToOpcode[2][Is32Bit], {Dst}, {LHS, RHS},
MIRBuilder);
}
MachineInstr *
AArch64InstructionSelector::emitADD(Register DefReg, MachineOperand &LHS,
MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const {
const std::array<std::array<unsigned, 2>, 5> OpcTable{
{{AArch64::ADDXri, AArch64::ADDWri},
{AArch64::ADDXrs, AArch64::ADDWrs},
{AArch64::ADDXrr, AArch64::ADDWrr},
{AArch64::SUBXri, AArch64::SUBWri},
{AArch64::ADDXrx, AArch64::ADDWrx}}};
return emitAddSub(OpcTable, DefReg, LHS, RHS, MIRBuilder);
}
MachineInstr *
AArch64InstructionSelector::emitADDS(Register Dst, MachineOperand &LHS,
MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const {
const std::array<std::array<unsigned, 2>, 5> OpcTable{
{{AArch64::ADDSXri, AArch64::ADDSWri},
{AArch64::ADDSXrs, AArch64::ADDSWrs},
{AArch64::ADDSXrr, AArch64::ADDSWrr},
{AArch64::SUBSXri, AArch64::SUBSWri},
{AArch64::ADDSXrx, AArch64::ADDSWrx}}};
return emitAddSub(OpcTable, Dst, LHS, RHS, MIRBuilder);
}
MachineInstr *
AArch64InstructionSelector::emitSUBS(Register Dst, MachineOperand &LHS,
MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const {
const std::array<std::array<unsigned, 2>, 5> OpcTable{
{{AArch64::SUBSXri, AArch64::SUBSWri},
{AArch64::SUBSXrs, AArch64::SUBSWrs},
{AArch64::SUBSXrr, AArch64::SUBSWrr},
{AArch64::ADDSXri, AArch64::ADDSWri},
{AArch64::SUBSXrx, AArch64::SUBSWrx}}};
return emitAddSub(OpcTable, Dst, LHS, RHS, MIRBuilder);
}
MachineInstr *
AArch64InstructionSelector::emitCMN(MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const {
MachineRegisterInfo &MRI = MIRBuilder.getMF().getRegInfo();
bool Is32Bit = (MRI.getType(LHS.getReg()).getSizeInBits() == 32);
auto RC = Is32Bit ? &AArch64::GPR32RegClass : &AArch64::GPR64RegClass;
return emitADDS(MRI.createVirtualRegister(RC), LHS, RHS, MIRBuilder);
}
MachineInstr *
AArch64InstructionSelector::emitTST(MachineOperand &LHS, MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const {
assert(LHS.isReg() && RHS.isReg() && "Expected register operands?");
MachineRegisterInfo &MRI = MIRBuilder.getMF().getRegInfo();
LLT Ty = MRI.getType(LHS.getReg());
unsigned RegSize = Ty.getSizeInBits();
bool Is32Bit = (RegSize == 32);
const unsigned OpcTable[3][2] = {{AArch64::ANDSXri, AArch64::ANDSWri},
{AArch64::ANDSXrs, AArch64::ANDSWrs},
{AArch64::ANDSXrr, AArch64::ANDSWrr}};
// ANDS needs a logical immediate for its immediate form. Check if we can
// fold one in.
if (auto ValAndVReg = getConstantVRegValWithLookThrough(RHS.getReg(), MRI)) {
int64_t Imm = ValAndVReg->Value.getSExtValue();
if (AArch64_AM::isLogicalImmediate(Imm, RegSize)) {
auto TstMI = MIRBuilder.buildInstr(OpcTable[0][Is32Bit], {Ty}, {LHS});
TstMI.addImm(AArch64_AM::encodeLogicalImmediate(Imm, RegSize));
constrainSelectedInstRegOperands(*TstMI, TII, TRI, RBI);
return &*TstMI;
}
}
if (auto Fns = selectLogicalShiftedRegister(RHS))
return emitInstr(OpcTable[1][Is32Bit], {Ty}, {LHS}, MIRBuilder, Fns);
return emitInstr(OpcTable[2][Is32Bit], {Ty}, {LHS, RHS}, MIRBuilder);
}
MachineInstr *AArch64InstructionSelector::emitIntegerCompare(
MachineOperand &LHS, MachineOperand &RHS, MachineOperand &Predicate,
MachineIRBuilder &MIRBuilder) const {
assert(LHS.isReg() && RHS.isReg() && "Expected LHS and RHS to be registers!");
assert(Predicate.isPredicate() && "Expected predicate?");
MachineRegisterInfo &MRI = MIRBuilder.getMF().getRegInfo();
LLT CmpTy = MRI.getType(LHS.getReg());
assert(!CmpTy.isVector() && "Expected scalar or pointer");
unsigned Size = CmpTy.getSizeInBits();
(void)Size;
assert((Size == 32 || Size == 64) && "Expected a 32-bit or 64-bit LHS/RHS?");
// Fold the compare into a cmn or tst if possible.
if (auto FoldCmp = tryFoldIntegerCompare(LHS, RHS, Predicate, MIRBuilder))
return FoldCmp;
auto Dst = MRI.cloneVirtualRegister(LHS.getReg());
return emitSUBS(Dst, LHS, RHS, MIRBuilder);
}
MachineInstr *AArch64InstructionSelector::emitCSetForFCmp(
Register Dst, CmpInst::Predicate Pred, MachineIRBuilder &MIRBuilder) const {
MachineRegisterInfo &MRI = *MIRBuilder.getMRI();
#ifndef NDEBUG
LLT Ty = MRI.getType(Dst);
assert(!Ty.isVector() && Ty.getSizeInBits() == 32 &&
"Expected a 32-bit scalar register?");
#endif
const Register ZeroReg = AArch64::WZR;
auto EmitCSet = [&](Register CsetDst, AArch64CC::CondCode CC) {
auto CSet =
MIRBuilder.buildInstr(AArch64::CSINCWr, {CsetDst}, {ZeroReg, ZeroReg})
.addImm(getInvertedCondCode(CC));
constrainSelectedInstRegOperands(*CSet, TII, TRI, RBI);
return &*CSet;
};
AArch64CC::CondCode CC1, CC2;
changeFCMPPredToAArch64CC(Pred, CC1, CC2);
if (CC2 == AArch64CC::AL)
return EmitCSet(Dst, CC1);
const TargetRegisterClass *RC = &AArch64::GPR32RegClass;
Register Def1Reg = MRI.createVirtualRegister(RC);
Register Def2Reg = MRI.createVirtualRegister(RC);
EmitCSet(Def1Reg, CC1);
EmitCSet(Def2Reg, CC2);
auto OrMI = MIRBuilder.buildInstr(AArch64::ORRWrr, {Dst}, {Def1Reg, Def2Reg});
constrainSelectedInstRegOperands(*OrMI, TII, TRI, RBI);
return &*OrMI;
}
MachineInstr *
AArch64InstructionSelector::emitFPCompare(Register LHS, Register RHS,
MachineIRBuilder &MIRBuilder,
Optional<CmpInst::Predicate> Pred) const {
MachineRegisterInfo &MRI = *MIRBuilder.getMRI();
LLT Ty = MRI.getType(LHS);
if (Ty.isVector())
return nullptr;
unsigned OpSize = Ty.getSizeInBits();
if (OpSize != 32 && OpSize != 64)
return nullptr;
// If this is a compare against +0.0, then we don't have
// to explicitly materialize a constant.
const ConstantFP *FPImm = getConstantFPVRegVal(RHS, MRI);
bool ShouldUseImm = FPImm && (FPImm->isZero() && !FPImm->isNegative());
auto IsEqualityPred = [](CmpInst::Predicate P) {
return P == CmpInst::FCMP_OEQ || P == CmpInst::FCMP_ONE ||
P == CmpInst::FCMP_UEQ || P == CmpInst::FCMP_UNE;
};
if (!ShouldUseImm && Pred && IsEqualityPred(*Pred)) {
// Try commutating the operands.
const ConstantFP *LHSImm = getConstantFPVRegVal(LHS, MRI);
if (LHSImm && (LHSImm->isZero() && !LHSImm->isNegative())) {
ShouldUseImm = true;
std::swap(LHS, RHS);
}
}
unsigned CmpOpcTbl[2][2] = {{AArch64::FCMPSrr, AArch64::FCMPDrr},
{AArch64::FCMPSri, AArch64::FCMPDri}};
unsigned CmpOpc = CmpOpcTbl[ShouldUseImm][OpSize == 64];
// 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 = MIRBuilder.buildInstr(CmpOpc).addUse(LHS);
if (!ShouldUseImm)
CmpMI.addUse(RHS);
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::emitCSetForICMP(Register DefReg, unsigned Pred,
MachineIRBuilder &MIRBuilder,
Register SrcReg) 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}, {SrcReg, SrcReg})
.addImm(InvCC);
constrainSelectedInstRegOperands(*I, TII, TRI, RBI);
return &*I;
}
std::pair<MachineInstr *, AArch64CC::CondCode>
AArch64InstructionSelector::emitOverflowOp(unsigned Opcode, Register Dst,
MachineOperand &LHS,
MachineOperand &RHS,
MachineIRBuilder &MIRBuilder) const {
switch (Opcode) {
default:
llvm_unreachable("Unexpected opcode!");
case TargetOpcode::G_SADDO:
return std::make_pair(emitADDS(Dst, LHS, RHS, MIRBuilder), AArch64CC::VS);
case TargetOpcode::G_UADDO:
return std::make_pair(emitADDS(Dst, LHS, RHS, MIRBuilder), AArch64CC::HS);
case TargetOpcode::G_SSUBO:
return std::make_pair(emitSUBS(Dst, LHS, RHS, MIRBuilder), AArch64CC::VS);
case TargetOpcode::G_USUBO:
return std::make_pair(emitSUBS(Dst, LHS, RHS, MIRBuilder), AArch64CC::LO);
}
}
bool AArch64InstructionSelector::tryOptSelect(MachineInstr &I) const {
MachineIRBuilder MIB(I);
MachineRegisterInfo &MRI = *MIB.getMRI();
// 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.
Register CondDefReg = CondDef->getOperand(0).getReg();
if (!MRI.hasOneNonDBGUse(CondDefReg)) {
// Unless it's another select.
for (const MachineInstr &UI : MRI.use_nodbg_instructions(CondDefReg)) {
if (CondDef == &UI)
continue;
if (UI.getOpcode() != TargetOpcode::G_SELECT)
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) {
auto Pred =
static_cast<CmpInst::Predicate>(CondDef->getOperand(1).getPredicate());
CondCode = changeICMPPredToAArch64CC(Pred);
emitIntegerCompare(CondDef->getOperand(2), CondDef->getOperand(3),
CondDef->getOperand(1), MIB);
} else {
// Get the condition code for the select.
auto Pred =
static_cast<CmpInst::Predicate>(CondDef->getOperand(1).getPredicate());
AArch64CC::CondCode CondCode2;
changeFCMPPredToAArch64CC(Pred, 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;
if (!emitFPCompare(CondDef->getOperand(2).getReg(),
CondDef->getOperand(3).getReg(), MIB)) {
LLVM_DEBUG(dbgs() << "Couldn't emit compare for select!\n");
return false;
}
}
// Emit the select.
emitSelect(I.getOperand(0).getReg(), I.getOperand(2).getReg(),
I.getOperand(3).getReg(), CondCode, MIB);
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
// 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);
auto P = static_cast<CmpInst::Predicate>(Predicate.getPredicate());
// Given this:
//
// x = G_SUB 0, y
// G_ICMP x, z
//
// Produce this:
//
// cmn y, z
if (isCMN(LHSDef, P, MRI))
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, P, MRI))
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 (!CmpInst::isUnsigned(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),
LHSDef->getOperand(2), MIRBuilder);
}
return nullptr;
}
bool AArch64InstructionSelector::selectShuffleVector(
MachineInstr &I, MachineRegisterInfo &MRI) const {
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)},
{RegSeq, IndexLoad->getOperand(0)});
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.getSExtValue();
// 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;
}
MachineInstr *
AArch64InstructionSelector::emitConstantVector(Register Dst, Constant *CV,
MachineIRBuilder &MIRBuilder,
MachineRegisterInfo &MRI) const {
LLT DstTy = MRI.getType(Dst);
unsigned DstSize = DstTy.getSizeInBits();
if (CV->isNullValue()) {
if (DstSize == 128) {
auto Mov =
MIRBuilder.buildInstr(AArch64::MOVIv2d_ns, {Dst}, {}).addImm(0);
constrainSelectedInstRegOperands(*Mov, TII, TRI, RBI);
return &*Mov;
}
if (DstSize == 64) {
auto Mov =
MIRBuilder
.buildInstr(AArch64::MOVIv2d_ns, {&AArch64::FPR128RegClass}, {})
.addImm(0);
auto Copy = MIRBuilder.buildInstr(TargetOpcode::COPY, {Dst}, {})
.addReg(Mov.getReg(0), 0, AArch64::dsub);
RBI.constrainGenericRegister(Dst, AArch64::FPR64RegClass, MRI);
return &*Copy;
}
}
auto *CPLoad = emitLoadFromConstantPool(CV, MIRBuilder);
if (!CPLoad) {
LLVM_DEBUG(dbgs() << "Could not generate cp load for constant vector!");
return nullptr;
}
auto Copy = MIRBuilder.buildCopy(Dst, CPLoad->getOperand(0));
RBI.constrainGenericRegister(
Dst, *MRI.getRegClass(CPLoad->getOperand(0).getReg()), MRI);
return &*Copy;
}
bool AArch64InstructionSelector::tryOptConstantBuildVec(
MachineInstr &I, LLT DstTy, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_BUILD_VECTOR);
unsigned DstSize = DstTy.getSizeInBits();
assert(DstSize <= 128 && "Unexpected build_vec type!");
if (DstSize < 32)
return false;
// Check if we're building a constant vector, in which case we want to
// generate a constant pool load instead of a vector insert sequence.
SmallVector<Constant *, 16> Csts;
for (unsigned Idx = 1; Idx < I.getNumOperands(); ++Idx) {
// Try to find G_CONSTANT or G_FCONSTANT
auto *OpMI =
getOpcodeDef(TargetOpcode::G_CONSTANT, I.getOperand(Idx).getReg(), MRI);
if (OpMI)
Csts.emplace_back(
const_cast<ConstantInt *>(OpMI->getOperand(1).getCImm()));
else if ((OpMI = getOpcodeDef(TargetOpcode::G_FCONSTANT,
I.getOperand(Idx).getReg(), MRI)))
Csts.emplace_back(
const_cast<ConstantFP *>(OpMI->getOperand(1).getFPImm()));
else
return false;
}
Constant *CV = ConstantVector::get(Csts);
MachineIRBuilder MIB(I);
if (!emitConstantVector(I.getOperand(0).getReg(), CV, MIB, MRI))
return false;
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 (tryOptConstantBuildVec(I, DstTy, MRI))
return true;
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:
MIRBuilder.buildInstr(AArch64::BRK, {}, {}).addImm(0xF000);
break;
case Intrinsic::ubsantrap:
MIRBuilder.buildInstr(AArch64::BRK, {}, {})
.addImm(I.getOperand(1).getImm() | ('U' << 8));
break;
}
I.eraseFromParent();
return true;
}
bool AArch64InstructionSelector::selectIntrinsic(MachineInstr &I,
MachineRegisterInfo &MRI) {
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;
}
case Intrinsic::frameaddress:
case Intrinsic::returnaddress: {
MachineFunction &MF = *I.getParent()->getParent();
MachineFrameInfo &MFI = MF.getFrameInfo();
unsigned Depth = I.getOperand(2).getImm();
Register DstReg = I.getOperand(0).getReg();
RBI.constrainGenericRegister(DstReg, AArch64::GPR64RegClass, MRI);
if (Depth == 0 && IntrinID == Intrinsic::returnaddress) {
if (!MFReturnAddr) {
// Insert the copy from LR/X30 into the entry block, before it can be
// clobbered by anything.
MFI.setReturnAddressIsTaken(true);
MFReturnAddr = getFunctionLiveInPhysReg(MF, TII, AArch64::LR,
AArch64::GPR64RegClass);
}
if (STI.hasPAuth()) {
MIRBuilder.buildInstr(AArch64::XPACI, {DstReg}, {MFReturnAddr});
} else {
MIRBuilder.buildCopy({Register(AArch64::LR)}, {MFReturnAddr});
MIRBuilder.buildInstr(AArch64::XPACLRI);
MIRBuilder.buildCopy({DstReg}, {Register(AArch64::LR)});
}
I.eraseFromParent();
return true;
}
MFI.setFrameAddressIsTaken(true);
Register FrameAddr(AArch64::FP);
while (Depth--) {
Register NextFrame = MRI.createVirtualRegister(&AArch64::GPR64spRegClass);
auto Ldr =
MIRBuilder.buildInstr(AArch64::LDRXui, {NextFrame}, {FrameAddr})
.addImm(0);
constrainSelectedInstRegOperands(*Ldr, TII, TRI, RBI);
FrameAddr = NextFrame;
}
if (IntrinID == Intrinsic::frameaddress)
MIRBuilder.buildCopy({DstReg}, {FrameAddr});
else {
MFI.setReturnAddressIsTaken(true);
if (STI.hasPAuth()) {
Register TmpReg = MRI.createVirtualRegister(&AArch64::GPR64RegClass);
MIRBuilder.buildInstr(AArch64::LDRXui, {TmpReg}, {FrameAddr}).addImm(1);
MIRBuilder.buildInstr(AArch64::XPACI, {DstReg}, {TmpReg});
} else {
MIRBuilder.buildInstr(AArch64::LDRXui, {Register(AArch64::LR)}, {FrameAddr}).addImm(1);
MIRBuilder.buildInstr(AArch64::XPACLRI);
MIRBuilder.buildCopy({DstReg}, {Register(AArch64::LR)});
}
}
I.eraseFromParent();
return true;
}
}
return false;
}
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.hasOneNonDBGUse(DefReg) ||
MI.getParent()->getParent()->getFunction().hasOptSize())
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_nodbg_instructions(DefReg),
[](MachineInstr &Use) { return Use.mayLoadOrStore(); });
}
static bool isSignExtendShiftType(AArch64_AM::ShiftExtendType Type) {
switch (Type) {
case AArch64_AM::SXTB:
case AArch64_AM::SXTH:
case AArch64_AM::SXTW:
return true;
default:
return false;
}
}
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();
bool LookedThroughZExt = false;
if (OffsetOpc != TargetOpcode::G_SHL && OffsetOpc != TargetOpcode::G_MUL) {
// Try to look through a ZEXT.
if (OffsetOpc != TargetOpcode::G_ZEXT || !WantsExt)
return None;
OffsetInst = MRI.getVRegDef(OffsetInst->getOperand(1).getReg());
OffsetOpc = OffsetInst->getOpcode();
LookedThroughZExt = true;
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.getSExtValue();
// 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, unless we looked through a
// G_ZEXT earlier.
if (!LookedThroughZExt) {
MachineInstr *ExtInst = getDefIgnoringCopies(OffsetReg, MRI);
auto Ext = getExtendTypeForInst(*ExtInst, MRI, true);
if (Ext == AArch64_AM::InvalidShiftExtend)
return None;
SignExtend = isSignExtendShiftType(Ext) ? 1 : 0;
// We only support SXTW for signed extension here.
if (SignExtend && Ext != AArch64_AM::SXTW)
return None;
OffsetReg = ExtInst->getOperand(1).getReg();
}
// Need a 32-bit wide register here.
MachineIRBuilder MIB(*MRI.getVRegDef(Root.getReg()));
OffsetReg = moveScalarRegClass(OffsetReg, AArch64::GPR32RegClass, 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.hasOneNonDBGUse(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 (!Root.isReg())
return None;
MachineInstr *PtrAdd =
getOpcodeDef(TargetOpcode::G_PTR_ADD, Root.getReg(), MRI);
if (!PtrAdd)
return None;
// Check for an immediates which cannot be encoded in the [base + imm]
// addressing mode, and can't be encoded in an add/sub. If this happens, we'll
// end up with code like:
//
// mov x0, wide
// add x1 base, x0
// ldr x2, [x1, x0]
//
// In this situation, we can use the [base, xreg] addressing mode to save an
// add/sub:
//
// mov x0, wide
// ldr x2, [base, x0]
auto ValAndVReg =
getConstantVRegValWithLookThrough(PtrAdd->getOperand(2).getReg(), MRI);
if (ValAndVReg) {
unsigned Scale = Log2_32(SizeInBytes);
int64_t ImmOff = ValAndVReg->Value.getSExtValue();
// Skip immediates that can be selected in the load/store addresing
// mode.
if (ImmOff % SizeInBytes == 0 && ImmOff >= 0 &&
ImmOff < (0x1000 << Scale))
return None;
// Helper lambda to decide whether or not it is preferable to emit an add.
auto isPreferredADD = [](int64_t ImmOff) {
// Constants in [0x0, 0xfff] can be encoded in an add.
if ((ImmOff & 0xfffffffffffff000LL) == 0x0LL)
return true;
// Can it be encoded in an add lsl #12?
if ((ImmOff & 0xffffffffff000fffLL) != 0x0LL)
return false;
// It can be encoded in an add lsl #12, but we may not want to. If it is
// possible to select this as a single movz, then prefer that. A single
// movz is faster than an add with a shift.
return (ImmOff & 0xffffffffff00ffffLL) != 0x0LL &&
(ImmOff & 0xffffffffffff0fffLL) != 0x0LL;
};
// If the immediate can be encoded in a single add/sub, then bail out.
if (isPreferredADD(ImmOff) || isPreferredADD(-ImmOff))
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 = moveScalarRegClass(OffsetInst->getOperand(1).getReg(),
AArch64::GPR32RegClass, 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;
}
InstructionSelector::ComplexRendererFns
AArch64InstructionSelector::tryFoldAddLowIntoImm(MachineInstr &RootDef,
unsigned Size,
MachineRegisterInfo &MRI) const {
if (RootDef.getOpcode() != AArch64::G_ADD_LOW)
return None;
MachineInstr &Adrp = *MRI.getVRegDef(RootDef.getOperand(1).getReg());
if (Adrp.getOpcode() != AArch64::ADRP)
return None;
// TODO: add heuristics like isWorthFoldingADDlow() from SelectionDAG.
auto Offset = Adrp.getOperand(1).getOffset();
if (Offset % Size != 0)
return None;
auto GV = Adrp.getOperand(1).getGlobal();
if (GV->isThreadLocal())
return None;
auto &MF = *RootDef.getParent()->getParent();
if (GV->getPointerAlignment(MF.getDataLayout()) < Size)
return None;
unsigned OpFlags = STI.ClassifyGlobalReference(GV, MF.getTarget());
MachineIRBuilder MIRBuilder(RootDef);
Register AdrpReg = Adrp.getOperand(0).getReg();
return {{[=](MachineInstrBuilder &MIB) { MIB.addUse(AdrpReg); },
[=](MachineInstrBuilder &MIB) {
MIB.addGlobalAddress(GV, Offset,
OpFlags | AArch64II::MO_PAGEOFF |
AArch64II::MO_NC);
}}};
}
/// 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 {
MachineFunction &MF = *Root.getParent()->getParent()->getParent();
MachineRegisterInfo &MRI = MF.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); },
}};
}
CodeModel::Model CM = MF.getTarget().getCodeModel();
// Check if we can fold in the ADD of small code model ADRP + ADD address.
if (CM == CodeModel::Small) {
auto OpFns = tryFoldAddLowIntoImm(*RootDef, Size, MRI);
if (OpFns)
return OpFns;
}
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;
if (Opc == TargetOpcode::G_SEXT)
Size = MRI.getType(MI.getOperand(1).getReg()).getSizeInBits();
else
Size = MI.getOperand(2).getImm();
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::moveScalarRegClass(
Register Reg, const TargetRegisterClass &RC, MachineIRBuilder &MIB) const {
MachineRegisterInfo &MRI = *MIB.getMRI();
auto Ty = MRI.getType(Reg);
assert(!Ty.isVector() && "Expected scalars only!");
if (Ty.getSizeInBits() == TRI.getRegSizeInBits(RC))
return Reg;
// Create a copy and immediately select it.
// FIXME: We should have an emitCopy function?
auto Copy = MIB.buildCopy({&RC}, {Reg});
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 = moveScalarRegClass(ExtReg, AArch64::GPR32RegClass, 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 =
getConstantVRegSExtVal(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);
}
void AArch64InstructionSelector::renderFPImm16(MachineInstrBuilder &MIB,
const MachineInstr &MI,
int OpIdx) const {
assert(MI.getOpcode() == TargetOpcode::G_FCONSTANT && OpIdx == -1 &&
"Expected G_FCONSTANT");
MIB.addImm(
AArch64_AM::getFP16Imm(MI.getOperand(1).getFPImm()->getValueAPF()));
}
void AArch64InstructionSelector::renderFPImm32(MachineInstrBuilder &MIB,
const MachineInstr &MI,
int OpIdx) const {
assert(MI.getOpcode() == TargetOpcode::G_FCONSTANT && OpIdx == -1 &&
"Expected G_FCONSTANT");
MIB.addImm(
AArch64_AM::getFP32Imm(MI.getOperand(1).getFPImm()->getValueAPF()));
}
void AArch64InstructionSelector::renderFPImm64(MachineInstrBuilder &MIB,
const MachineInstr &MI,
int OpIdx) const {
assert(MI.getOpcode() == TargetOpcode::G_FCONSTANT && OpIdx == -1 &&
"Expected G_FCONSTANT");
MIB.addImm(
AArch64_AM::getFP64Imm(MI.getOperand(1).getFPImm()->getValueAPF()));
}
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;
}
}
// Perform fixups on the given PHI instruction's operands to force them all
// to be the same as the destination regbank.
static void fixupPHIOpBanks(MachineInstr &MI, MachineRegisterInfo &MRI,
const AArch64RegisterBankInfo &RBI) {
assert(MI.getOpcode() == TargetOpcode::G_PHI && "Expected a G_PHI");
Register DstReg = MI.getOperand(0).getReg();
const RegisterBank *DstRB = MRI.getRegBankOrNull(DstReg);
assert(DstRB && "Expected PHI dst to have regbank assigned");
MachineIRBuilder MIB(MI);
// Go through each operand and ensure it has the same regbank.
for (unsigned OpIdx = 1; OpIdx < MI.getNumOperands(); ++OpIdx) {
MachineOperand &MO = MI.getOperand(OpIdx);
if (!MO.isReg())
continue;
Register OpReg = MO.getReg();
const RegisterBank *RB = MRI.getRegBankOrNull(OpReg);
if (RB != DstRB) {
// Insert a cross-bank copy.
auto *OpDef = MRI.getVRegDef(OpReg);
const LLT &Ty = MRI.getType(OpReg);
MIB.setInsertPt(*OpDef->getParent(), std::next(OpDef->getIterator()));
auto Copy = MIB.buildCopy(Ty, OpReg);
MRI.setRegBank(Copy.getReg(0), *DstRB);
MO.setReg(Copy.getReg(0));
}
}
}
void AArch64InstructionSelector::processPHIs(MachineFunction &MF) {
// We're looking for PHIs, build a list so we don't invalidate iterators.
MachineRegisterInfo &MRI = MF.getRegInfo();
SmallVector<MachineInstr *, 32> Phis;
for (auto &BB : MF) {
for (auto &MI : BB) {
if (MI.getOpcode() == TargetOpcode::G_PHI)
Phis.emplace_back(&MI);
}
}
for (auto *MI : Phis) {
// We need to do some work here if the operand types are < 16 bit and they
// are split across fpr/gpr banks. Since all types <32b on gpr
// end up being assigned gpr32 regclasses, we can end up with PHIs here
// which try to select between a gpr32 and an fpr16. Ideally RBS shouldn't
// be selecting heterogenous regbanks for operands if possible, but we
// still need to be able to deal with it here.
//
// To fix this, if we have a gpr-bank operand < 32b in size and at least
// one other operand is on the fpr bank, then we add cross-bank copies
// to homogenize the operand banks. For simplicity the bank that we choose
// to settle on is whatever bank the def operand has. For example:
//
// %endbb:
// %dst:gpr(s16) = G_PHI %in1:gpr(s16), %bb1, %in2:fpr(s16), %bb2
// =>
// %bb2:
// ...
// %in2_copy:gpr(s16) = COPY %in2:fpr(s16)
// ...
// %endbb:
// %dst:gpr(s16) = G_PHI %in1:gpr(s16), %bb1, %in2_copy:gpr(s16), %bb2
bool HasGPROp = false, HasFPROp = false;
for (unsigned OpIdx = 1; OpIdx < MI->getNumOperands(); ++OpIdx) {
const auto &MO = MI->getOperand(OpIdx);
if (!MO.isReg())
continue;
const LLT &Ty = MRI.getType(MO.getReg());
if (!Ty.isValid() || !Ty.isScalar())
break;
if (Ty.getSizeInBits() >= 32)
break;
const RegisterBank *RB = MRI.getRegBankOrNull(MO.getReg());
// If for some reason we don't have a regbank yet. Don't try anything.
if (!RB)
break;
if (RB->getID() == AArch64::GPRRegBankID)
HasGPROp = true;
else
HasFPROp = true;
}
// We have heterogenous regbanks, need to fixup.
if (HasGPROp && HasFPROp)
fixupPHIOpBanks(*MI, MRI, RBI);
}
}
namespace llvm {
InstructionSelector *
createAArch64InstructionSelector(const AArch64TargetMachine &TM,
AArch64Subtarget &Subtarget,
AArch64RegisterBankInfo &RBI) {
return new AArch64InstructionSelector(TM, Subtarget, RBI);
}
}