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llvm-mirror/lib/Target/X86/X86InstructionSelector.cpp
Alexander Ivchenko 4661c1b4e5 [GlobalIsel][X86] Support for G_SDIV instruction 
Reviewed By: igorb

Differential Revision: https://reviews.llvm.org/D44430

llvm-svn: 327520
2018-03-14 15:41:11 +00:00

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54 KiB
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//===- X86InstructionSelector.cpp -----------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements the targeting of the InstructionSelector class for
/// X86.
/// \todo This should be generated by TableGen.
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/X86BaseInfo.h"
#include "X86InstrBuilder.h"
#include "X86InstrInfo.h"
#include "X86RegisterBankInfo.h"
#include "X86RegisterInfo.h"
#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
#include "llvm/CodeGen/GlobalISel/InstructionSelectorImpl.h"
#include "llvm/CodeGen/GlobalISel/RegisterBank.h"
#include "llvm/CodeGen/GlobalISel/Utils.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetOpcodes.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/Support/AtomicOrdering.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/LowLevelTypeImpl.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdint>
#include <tuple>
#define DEBUG_TYPE "X86-isel"
using namespace llvm;
namespace {
#define GET_GLOBALISEL_PREDICATE_BITSET
#include "X86GenGlobalISel.inc"
#undef GET_GLOBALISEL_PREDICATE_BITSET
class X86InstructionSelector : public InstructionSelector {
public:
X86InstructionSelector(const X86TargetMachine &TM, const X86Subtarget &STI,
const X86RegisterBankInfo &RBI);
bool select(MachineInstr &I, CodeGenCoverage &CoverageInfo) const override;
static const char *getName() { return DEBUG_TYPE; }
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;
// TODO: remove after supported by Tablegen-erated instruction selection.
unsigned getLoadStoreOp(const LLT &Ty, const RegisterBank &RB, unsigned Opc,
uint64_t Alignment) const;
bool selectLoadStoreOp(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectFrameIndexOrGep(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectGlobalValue(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectConstant(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectTruncOrPtrToInt(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectZext(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectAnyext(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectCmp(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectUadde(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectCopy(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectUnmergeValues(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF,
CodeGenCoverage &CoverageInfo) const;
bool selectMergeValues(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF,
CodeGenCoverage &CoverageInfo) const;
bool selectInsert(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectExtract(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectCondBranch(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectTurnIntoCOPY(MachineInstr &I, MachineRegisterInfo &MRI,
const unsigned DstReg,
const TargetRegisterClass *DstRC,
const unsigned SrcReg,
const TargetRegisterClass *SrcRC) const;
bool materializeFP(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectImplicitDefOrPHI(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectShift(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectSDiv(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
// emit insert subreg instruction and insert it before MachineInstr &I
bool emitInsertSubreg(unsigned DstReg, unsigned SrcReg, MachineInstr &I,
MachineRegisterInfo &MRI, MachineFunction &MF) const;
// emit extract subreg instruction and insert it before MachineInstr &I
bool emitExtractSubreg(unsigned DstReg, unsigned SrcReg, MachineInstr &I,
MachineRegisterInfo &MRI, MachineFunction &MF) const;
const TargetRegisterClass *getRegClass(LLT Ty, const RegisterBank &RB) const;
const TargetRegisterClass *getRegClass(LLT Ty, unsigned Reg,
MachineRegisterInfo &MRI) const;
const X86TargetMachine &TM;
const X86Subtarget &STI;
const X86InstrInfo &TII;
const X86RegisterInfo &TRI;
const X86RegisterBankInfo &RBI;
#define GET_GLOBALISEL_PREDICATES_DECL
#include "X86GenGlobalISel.inc"
#undef GET_GLOBALISEL_PREDICATES_DECL
#define GET_GLOBALISEL_TEMPORARIES_DECL
#include "X86GenGlobalISel.inc"
#undef GET_GLOBALISEL_TEMPORARIES_DECL
};
} // end anonymous namespace
#define GET_GLOBALISEL_IMPL
#include "X86GenGlobalISel.inc"
#undef GET_GLOBALISEL_IMPL
X86InstructionSelector::X86InstructionSelector(const X86TargetMachine &TM,
const X86Subtarget &STI,
const X86RegisterBankInfo &RBI)
: InstructionSelector(), TM(TM), STI(STI), TII(*STI.getInstrInfo()),
TRI(*STI.getRegisterInfo()), RBI(RBI),
#define GET_GLOBALISEL_PREDICATES_INIT
#include "X86GenGlobalISel.inc"
#undef GET_GLOBALISEL_PREDICATES_INIT
#define GET_GLOBALISEL_TEMPORARIES_INIT
#include "X86GenGlobalISel.inc"
#undef GET_GLOBALISEL_TEMPORARIES_INIT
{
}
// FIXME: This should be target-independent, inferred from the types declared
// for each class in the bank.
const TargetRegisterClass *
X86InstructionSelector::getRegClass(LLT Ty, const RegisterBank &RB) const {
if (RB.getID() == X86::GPRRegBankID) {
if (Ty.getSizeInBits() <= 8)
return &X86::GR8RegClass;
if (Ty.getSizeInBits() == 16)
return &X86::GR16RegClass;
if (Ty.getSizeInBits() == 32)
return &X86::GR32RegClass;
if (Ty.getSizeInBits() == 64)
return &X86::GR64RegClass;
}
if (RB.getID() == X86::VECRRegBankID) {
if (Ty.getSizeInBits() == 32)
return STI.hasAVX512() ? &X86::FR32XRegClass : &X86::FR32RegClass;
if (Ty.getSizeInBits() == 64)
return STI.hasAVX512() ? &X86::FR64XRegClass : &X86::FR64RegClass;
if (Ty.getSizeInBits() == 128)
return STI.hasAVX512() ? &X86::VR128XRegClass : &X86::VR128RegClass;
if (Ty.getSizeInBits() == 256)
return STI.hasAVX512() ? &X86::VR256XRegClass : &X86::VR256RegClass;
if (Ty.getSizeInBits() == 512)
return &X86::VR512RegClass;
}
llvm_unreachable("Unknown RegBank!");
}
const TargetRegisterClass *
X86InstructionSelector::getRegClass(LLT Ty, unsigned Reg,
MachineRegisterInfo &MRI) const {
const RegisterBank &RegBank = *RBI.getRegBank(Reg, MRI, TRI);
return getRegClass(Ty, RegBank);
}
static unsigned getSubRegIndex(const TargetRegisterClass *RC) {
unsigned SubIdx = X86::NoSubRegister;
if (RC == &X86::GR32RegClass) {
SubIdx = X86::sub_32bit;
} else if (RC == &X86::GR16RegClass) {
SubIdx = X86::sub_16bit;
} else if (RC == &X86::GR8RegClass) {
SubIdx = X86::sub_8bit;
}
return SubIdx;
}
static const TargetRegisterClass *getRegClassFromGRPhysReg(unsigned Reg) {
assert(TargetRegisterInfo::isPhysicalRegister(Reg));
if (X86::GR64RegClass.contains(Reg))
return &X86::GR64RegClass;
if (X86::GR32RegClass.contains(Reg))
return &X86::GR32RegClass;
if (X86::GR16RegClass.contains(Reg))
return &X86::GR16RegClass;
if (X86::GR8RegClass.contains(Reg))
return &X86::GR8RegClass;
llvm_unreachable("Unknown RegClass for PhysReg!");
}
// Set X86 Opcode and constrain DestReg.
bool X86InstructionSelector::selectCopy(MachineInstr &I,
MachineRegisterInfo &MRI) const {
unsigned DstReg = I.getOperand(0).getReg();
const unsigned DstSize = RBI.getSizeInBits(DstReg, MRI, TRI);
const RegisterBank &DstRegBank = *RBI.getRegBank(DstReg, MRI, TRI);
unsigned SrcReg = I.getOperand(1).getReg();
const unsigned SrcSize = RBI.getSizeInBits(SrcReg, MRI, TRI);
const RegisterBank &SrcRegBank = *RBI.getRegBank(SrcReg, MRI, TRI);
if (TargetRegisterInfo::isPhysicalRegister(DstReg)) {
assert(I.isCopy() && "Generic operators do not allow physical registers");
if (DstSize > SrcSize && SrcRegBank.getID() == X86::GPRRegBankID &&
DstRegBank.getID() == X86::GPRRegBankID) {
const TargetRegisterClass *SrcRC =
getRegClass(MRI.getType(SrcReg), SrcRegBank);
const TargetRegisterClass *DstRC = getRegClassFromGRPhysReg(DstReg);
if (SrcRC != DstRC) {
// This case can be generated by ABI lowering, performe anyext
unsigned ExtSrc = MRI.createVirtualRegister(DstRC);
BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(TargetOpcode::SUBREG_TO_REG))
.addDef(ExtSrc)
.addImm(0)
.addReg(SrcReg)
.addImm(getSubRegIndex(SrcRC));
I.getOperand(1).setReg(ExtSrc);
}
}
return true;
}
assert((!TargetRegisterInfo::isPhysicalRegister(SrcReg) || I.isCopy()) &&
"No phys reg on generic operators");
assert((DstSize == SrcSize ||
// Copies are a mean to setup initial types, the number of
// bits may not exactly match.
(TargetRegisterInfo::isPhysicalRegister(SrcReg) &&
DstSize <= RBI.getSizeInBits(SrcReg, MRI, TRI))) &&
"Copy with different width?!");
const TargetRegisterClass *DstRC =
getRegClass(MRI.getType(DstReg), DstRegBank);
if (SrcRegBank.getID() == X86::GPRRegBankID &&
DstRegBank.getID() == X86::GPRRegBankID && SrcSize > DstSize &&
TargetRegisterInfo::isPhysicalRegister(SrcReg)) {
// Change the physical register to performe truncate.
const TargetRegisterClass *SrcRC = getRegClassFromGRPhysReg(SrcReg);
if (DstRC != SrcRC) {
I.getOperand(1).setSubReg(getSubRegIndex(DstRC));
I.getOperand(1).substPhysReg(SrcReg, TRI);
}
}
// No need to constrain SrcReg. It will get constrained when
// we hit another of its use or its defs.
// Copies do not have constraints.
const TargetRegisterClass *OldRC = MRI.getRegClassOrNull(DstReg);
if (!OldRC || !DstRC->hasSubClassEq(OldRC)) {
if (!RBI.constrainGenericRegister(DstReg, *DstRC, MRI)) {
DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())
<< " operand\n");
return false;
}
}
I.setDesc(TII.get(X86::COPY));
return true;
}
bool X86InstructionSelector::select(MachineInstr &I,
CodeGenCoverage &CoverageInfo) 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();
unsigned Opcode = I.getOpcode();
if (!isPreISelGenericOpcode(Opcode)) {
// Certain non-generic instructions also need some special handling.
if (Opcode == TargetOpcode::LOAD_STACK_GUARD)
return false;
if (I.isCopy())
return selectCopy(I, MRI);
return true;
}
assert(I.getNumOperands() == I.getNumExplicitOperands() &&
"Generic instruction has unexpected implicit operands\n");
if (selectImpl(I, CoverageInfo))
return true;
DEBUG(dbgs() << " C++ instruction selection: "; I.print(dbgs()));
// TODO: This should be implemented by tblgen.
switch (I.getOpcode()) {
default:
return false;
case TargetOpcode::G_STORE:
case TargetOpcode::G_LOAD:
return selectLoadStoreOp(I, MRI, MF);
case TargetOpcode::G_GEP:
case TargetOpcode::G_FRAME_INDEX:
return selectFrameIndexOrGep(I, MRI, MF);
case TargetOpcode::G_GLOBAL_VALUE:
return selectGlobalValue(I, MRI, MF);
case TargetOpcode::G_CONSTANT:
return selectConstant(I, MRI, MF);
case TargetOpcode::G_FCONSTANT:
return materializeFP(I, MRI, MF);
case TargetOpcode::G_PTRTOINT:
case TargetOpcode::G_TRUNC:
return selectTruncOrPtrToInt(I, MRI, MF);
case TargetOpcode::G_INTTOPTR:
return selectCopy(I, MRI);
case TargetOpcode::G_ZEXT:
return selectZext(I, MRI, MF);
case TargetOpcode::G_ANYEXT:
return selectAnyext(I, MRI, MF);
case TargetOpcode::G_ICMP:
return selectCmp(I, MRI, MF);
case TargetOpcode::G_UADDE:
return selectUadde(I, MRI, MF);
case TargetOpcode::G_UNMERGE_VALUES:
return selectUnmergeValues(I, MRI, MF, CoverageInfo);
case TargetOpcode::G_MERGE_VALUES:
return selectMergeValues(I, MRI, MF, CoverageInfo);
case TargetOpcode::G_EXTRACT:
return selectExtract(I, MRI, MF);
case TargetOpcode::G_INSERT:
return selectInsert(I, MRI, MF);
case TargetOpcode::G_BRCOND:
return selectCondBranch(I, MRI, MF);
case TargetOpcode::G_IMPLICIT_DEF:
case TargetOpcode::G_PHI:
return selectImplicitDefOrPHI(I, MRI);
case TargetOpcode::G_SHL:
case TargetOpcode::G_ASHR:
case TargetOpcode::G_LSHR:
return selectShift(I, MRI, MF);
case TargetOpcode::G_SDIV:
return selectSDiv(I, MRI, MF);
}
return false;
}
unsigned X86InstructionSelector::getLoadStoreOp(const LLT &Ty,
const RegisterBank &RB,
unsigned Opc,
uint64_t Alignment) const {
bool Isload = (Opc == TargetOpcode::G_LOAD);
bool HasAVX = STI.hasAVX();
bool HasAVX512 = STI.hasAVX512();
bool HasVLX = STI.hasVLX();
if (Ty == LLT::scalar(8)) {
if (X86::GPRRegBankID == RB.getID())
return Isload ? X86::MOV8rm : X86::MOV8mr;
} else if (Ty == LLT::scalar(16)) {
if (X86::GPRRegBankID == RB.getID())
return Isload ? X86::MOV16rm : X86::MOV16mr;
} else if (Ty == LLT::scalar(32) || Ty == LLT::pointer(0, 32)) {
if (X86::GPRRegBankID == RB.getID())
return Isload ? X86::MOV32rm : X86::MOV32mr;
if (X86::VECRRegBankID == RB.getID())
return Isload ? (HasAVX512 ? X86::VMOVSSZrm
: HasAVX ? X86::VMOVSSrm : X86::MOVSSrm)
: (HasAVX512 ? X86::VMOVSSZmr
: HasAVX ? X86::VMOVSSmr : X86::MOVSSmr);
} else if (Ty == LLT::scalar(64) || Ty == LLT::pointer(0, 64)) {
if (X86::GPRRegBankID == RB.getID())
return Isload ? X86::MOV64rm : X86::MOV64mr;
if (X86::VECRRegBankID == RB.getID())
return Isload ? (HasAVX512 ? X86::VMOVSDZrm
: HasAVX ? X86::VMOVSDrm : X86::MOVSDrm)
: (HasAVX512 ? X86::VMOVSDZmr
: HasAVX ? X86::VMOVSDmr : X86::MOVSDmr);
} else if (Ty.isVector() && Ty.getSizeInBits() == 128) {
if (Alignment >= 16)
return Isload ? (HasVLX ? X86::VMOVAPSZ128rm
: HasAVX512
? X86::VMOVAPSZ128rm_NOVLX
: HasAVX ? X86::VMOVAPSrm : X86::MOVAPSrm)
: (HasVLX ? X86::VMOVAPSZ128mr
: HasAVX512
? X86::VMOVAPSZ128mr_NOVLX
: HasAVX ? X86::VMOVAPSmr : X86::MOVAPSmr);
else
return Isload ? (HasVLX ? X86::VMOVUPSZ128rm
: HasAVX512
? X86::VMOVUPSZ128rm_NOVLX
: HasAVX ? X86::VMOVUPSrm : X86::MOVUPSrm)
: (HasVLX ? X86::VMOVUPSZ128mr
: HasAVX512
? X86::VMOVUPSZ128mr_NOVLX
: HasAVX ? X86::VMOVUPSmr : X86::MOVUPSmr);
} else if (Ty.isVector() && Ty.getSizeInBits() == 256) {
if (Alignment >= 32)
return Isload ? (HasVLX ? X86::VMOVAPSZ256rm
: HasAVX512 ? X86::VMOVAPSZ256rm_NOVLX
: X86::VMOVAPSYrm)
: (HasVLX ? X86::VMOVAPSZ256mr
: HasAVX512 ? X86::VMOVAPSZ256mr_NOVLX
: X86::VMOVAPSYmr);
else
return Isload ? (HasVLX ? X86::VMOVUPSZ256rm
: HasAVX512 ? X86::VMOVUPSZ256rm_NOVLX
: X86::VMOVUPSYrm)
: (HasVLX ? X86::VMOVUPSZ256mr
: HasAVX512 ? X86::VMOVUPSZ256mr_NOVLX
: X86::VMOVUPSYmr);
} else if (Ty.isVector() && Ty.getSizeInBits() == 512) {
if (Alignment >= 64)
return Isload ? X86::VMOVAPSZrm : X86::VMOVAPSZmr;
else
return Isload ? X86::VMOVUPSZrm : X86::VMOVUPSZmr;
}
return Opc;
}
// Fill in an address from the given instruction.
static void X86SelectAddress(const MachineInstr &I,
const MachineRegisterInfo &MRI,
X86AddressMode &AM) {
assert(I.getOperand(0).isReg() && "unsupported opperand.");
assert(MRI.getType(I.getOperand(0).getReg()).isPointer() &&
"unsupported type.");
if (I.getOpcode() == TargetOpcode::G_GEP) {
if (auto COff = getConstantVRegVal(I.getOperand(2).getReg(), MRI)) {
int64_t Imm = *COff;
if (isInt<32>(Imm)) { // Check for displacement overflow.
AM.Disp = static_cast<int32_t>(Imm);
AM.Base.Reg = I.getOperand(1).getReg();
return;
}
}
} else if (I.getOpcode() == TargetOpcode::G_FRAME_INDEX) {
AM.Base.FrameIndex = I.getOperand(1).getIndex();
AM.BaseType = X86AddressMode::FrameIndexBase;
return;
}
// Default behavior.
AM.Base.Reg = I.getOperand(0).getReg();
}
bool X86InstructionSelector::selectLoadStoreOp(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
unsigned Opc = I.getOpcode();
assert((Opc == TargetOpcode::G_STORE || Opc == TargetOpcode::G_LOAD) &&
"unexpected instruction");
const unsigned DefReg = I.getOperand(0).getReg();
LLT Ty = MRI.getType(DefReg);
const RegisterBank &RB = *RBI.getRegBank(DefReg, MRI, TRI);
auto &MemOp = **I.memoperands_begin();
if (MemOp.getOrdering() != AtomicOrdering::NotAtomic) {
DEBUG(dbgs() << "Atomic load/store not supported yet\n");
return false;
}
unsigned NewOpc = getLoadStoreOp(Ty, RB, Opc, MemOp.getAlignment());
if (NewOpc == Opc)
return false;
X86AddressMode AM;
X86SelectAddress(*MRI.getVRegDef(I.getOperand(1).getReg()), MRI, AM);
I.setDesc(TII.get(NewOpc));
MachineInstrBuilder MIB(MF, I);
if (Opc == TargetOpcode::G_LOAD) {
I.RemoveOperand(1);
addFullAddress(MIB, AM);
} else {
// G_STORE (VAL, Addr), X86Store instruction (Addr, VAL)
I.RemoveOperand(1);
I.RemoveOperand(0);
addFullAddress(MIB, AM).addUse(DefReg);
}
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
static unsigned getLeaOP(LLT Ty, const X86Subtarget &STI) {
if (Ty == LLT::pointer(0, 64))
return X86::LEA64r;
else if (Ty == LLT::pointer(0, 32))
return STI.isTarget64BitILP32() ? X86::LEA64_32r : X86::LEA32r;
else
llvm_unreachable("Can't get LEA opcode. Unsupported type.");
}
bool X86InstructionSelector::selectFrameIndexOrGep(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
unsigned Opc = I.getOpcode();
assert((Opc == TargetOpcode::G_FRAME_INDEX || Opc == TargetOpcode::G_GEP) &&
"unexpected instruction");
const unsigned DefReg = I.getOperand(0).getReg();
LLT Ty = MRI.getType(DefReg);
// Use LEA to calculate frame index and GEP
unsigned NewOpc = getLeaOP(Ty, STI);
I.setDesc(TII.get(NewOpc));
MachineInstrBuilder MIB(MF, I);
if (Opc == TargetOpcode::G_FRAME_INDEX) {
addOffset(MIB, 0);
} else {
MachineOperand &InxOp = I.getOperand(2);
I.addOperand(InxOp); // set IndexReg
InxOp.ChangeToImmediate(1); // set Scale
MIB.addImm(0).addReg(0);
}
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
bool X86InstructionSelector::selectGlobalValue(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_GLOBAL_VALUE) &&
"unexpected instruction");
auto GV = I.getOperand(1).getGlobal();
if (GV->isThreadLocal()) {
return false; // TODO: we don't support TLS yet.
}
// Can't handle alternate code models yet.
if (TM.getCodeModel() != CodeModel::Small)
return false;
X86AddressMode AM;
AM.GV = GV;
AM.GVOpFlags = STI.classifyGlobalReference(GV);
// TODO: The ABI requires an extra load. not supported yet.
if (isGlobalStubReference(AM.GVOpFlags))
return false;
// TODO: This reference is relative to the pic base. not supported yet.
if (isGlobalRelativeToPICBase(AM.GVOpFlags))
return false;
if (STI.isPICStyleRIPRel()) {
// Use rip-relative addressing.
assert(AM.Base.Reg == 0 && AM.IndexReg == 0);
AM.Base.Reg = X86::RIP;
}
const unsigned DefReg = I.getOperand(0).getReg();
LLT Ty = MRI.getType(DefReg);
unsigned NewOpc = getLeaOP(Ty, STI);
I.setDesc(TII.get(NewOpc));
MachineInstrBuilder MIB(MF, I);
I.RemoveOperand(1);
addFullAddress(MIB, AM);
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
bool X86InstructionSelector::selectConstant(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_CONSTANT) &&
"unexpected instruction");
const unsigned DefReg = I.getOperand(0).getReg();
LLT Ty = MRI.getType(DefReg);
if (RBI.getRegBank(DefReg, MRI, TRI)->getID() != X86::GPRRegBankID)
return false;
uint64_t Val = 0;
if (I.getOperand(1).isCImm()) {
Val = I.getOperand(1).getCImm()->getZExtValue();
I.getOperand(1).ChangeToImmediate(Val);
} else if (I.getOperand(1).isImm()) {
Val = I.getOperand(1).getImm();
} else
llvm_unreachable("Unsupported operand type.");
unsigned NewOpc;
switch (Ty.getSizeInBits()) {
case 8:
NewOpc = X86::MOV8ri;
break;
case 16:
NewOpc = X86::MOV16ri;
break;
case 32:
NewOpc = X86::MOV32ri;
break;
case 64:
// TODO: in case isUInt<32>(Val), X86::MOV32ri can be used
if (isInt<32>(Val))
NewOpc = X86::MOV64ri32;
else
NewOpc = X86::MOV64ri;
break;
default:
llvm_unreachable("Can't select G_CONSTANT, unsupported type.");
}
I.setDesc(TII.get(NewOpc));
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
// Helper function for selectTruncOrPtrToInt and selectAnyext.
// Returns true if DstRC lives on a floating register class and
// SrcRC lives on a 128-bit vector class.
static bool canTurnIntoCOPY(const TargetRegisterClass *DstRC,
const TargetRegisterClass *SrcRC) {
return (DstRC == &X86::FR32RegClass || DstRC == &X86::FR32XRegClass ||
DstRC == &X86::FR64RegClass || DstRC == &X86::FR64XRegClass) &&
(SrcRC == &X86::VR128RegClass || SrcRC == &X86::VR128XRegClass);
}
bool X86InstructionSelector::selectTurnIntoCOPY(
MachineInstr &I, MachineRegisterInfo &MRI, const unsigned DstReg,
const TargetRegisterClass *DstRC, const unsigned SrcReg,
const TargetRegisterClass *SrcRC) const {
if (!RBI.constrainGenericRegister(SrcReg, *SrcRC, MRI) ||
!RBI.constrainGenericRegister(DstReg, *DstRC, MRI)) {
DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())
<< " operand\n");
return false;
}
I.setDesc(TII.get(X86::COPY));
return true;
}
bool X86InstructionSelector::selectTruncOrPtrToInt(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_TRUNC ||
I.getOpcode() == TargetOpcode::G_PTRTOINT) &&
"unexpected instruction");
const unsigned DstReg = I.getOperand(0).getReg();
const unsigned SrcReg = I.getOperand(1).getReg();
const LLT DstTy = MRI.getType(DstReg);
const LLT SrcTy = MRI.getType(SrcReg);
const RegisterBank &DstRB = *RBI.getRegBank(DstReg, MRI, TRI);
const RegisterBank &SrcRB = *RBI.getRegBank(SrcReg, MRI, TRI);
if (DstRB.getID() != SrcRB.getID()) {
DEBUG(dbgs() << TII.getName(I.getOpcode())
<< " input/output on different banks\n");
return false;
}
const TargetRegisterClass *DstRC = getRegClass(DstTy, DstRB);
const TargetRegisterClass *SrcRC = getRegClass(SrcTy, SrcRB);
if (!DstRC || !SrcRC)
return false;
// If that's truncation of the value that lives on the vector class and goes
// into the floating class, just replace it with copy, as we are able to
// select it as a regular move.
if (canTurnIntoCOPY(DstRC, SrcRC))
return selectTurnIntoCOPY(I, MRI, DstReg, DstRC, SrcReg, SrcRC);
if (DstRB.getID() != X86::GPRRegBankID)
return false;
unsigned SubIdx;
if (DstRC == SrcRC) {
// Nothing to be done
SubIdx = X86::NoSubRegister;
} else if (DstRC == &X86::GR32RegClass) {
SubIdx = X86::sub_32bit;
} else if (DstRC == &X86::GR16RegClass) {
SubIdx = X86::sub_16bit;
} else if (DstRC == &X86::GR8RegClass) {
SubIdx = X86::sub_8bit;
} else {
return false;
}
SrcRC = TRI.getSubClassWithSubReg(SrcRC, SubIdx);
if (!RBI.constrainGenericRegister(SrcReg, *SrcRC, MRI) ||
!RBI.constrainGenericRegister(DstReg, *DstRC, MRI)) {
DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())
<< "\n");
return false;
}
I.getOperand(1).setSubReg(SubIdx);
I.setDesc(TII.get(X86::COPY));
return true;
}
bool X86InstructionSelector::selectZext(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_ZEXT) && "unexpected instruction");
const unsigned DstReg = I.getOperand(0).getReg();
const unsigned SrcReg = I.getOperand(1).getReg();
const LLT DstTy = MRI.getType(DstReg);
const LLT SrcTy = MRI.getType(SrcReg);
assert(!(SrcTy == LLT::scalar(8) && DstTy == LLT::scalar(32)) &&
"8=>32 Zext is handled by tablegen");
assert(!(SrcTy == LLT::scalar(16) && DstTy == LLT::scalar(32)) &&
"16=>32 Zext is handled by tablegen");
const static struct ZextEntry {
LLT SrcTy;
LLT DstTy;
unsigned MovOp;
bool NeedSubregToReg;
} OpTable[] = {
{LLT::scalar(8), LLT::scalar(16), X86::MOVZX16rr8, false}, // i8 => i16
{LLT::scalar(8), LLT::scalar(64), X86::MOVZX32rr8, true}, // i8 => i64
{LLT::scalar(16), LLT::scalar(64), X86::MOVZX32rr16, true}, // i16 => i64
{LLT::scalar(32), LLT::scalar(64), 0, true} // i32 => i64
};
auto ZextEntryIt =
std::find_if(std::begin(OpTable), std::end(OpTable),
[SrcTy, DstTy](const ZextEntry &El) {
return El.DstTy == DstTy && El.SrcTy == SrcTy;
});
// Here we try to select Zext into a MOVZ and/or SUBREG_TO_REG instruction.
if (ZextEntryIt != std::end(OpTable)) {
const RegisterBank &DstRB = *RBI.getRegBank(DstReg, MRI, TRI);
const RegisterBank &SrcRB = *RBI.getRegBank(SrcReg, MRI, TRI);
const TargetRegisterClass *DstRC = getRegClass(DstTy, DstRB);
const TargetRegisterClass *SrcRC = getRegClass(SrcTy, SrcRB);
if (!RBI.constrainGenericRegister(SrcReg, *SrcRC, MRI) ||
!RBI.constrainGenericRegister(DstReg, *DstRC, MRI)) {
DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())
<< " operand\n");
return false;
}
unsigned TransitRegTo = DstReg;
unsigned TransitRegFrom = SrcReg;
if (ZextEntryIt->MovOp) {
// If we select Zext into MOVZ + SUBREG_TO_REG, we need to have
// a transit register in between: create it here.
if (ZextEntryIt->NeedSubregToReg) {
TransitRegFrom = MRI.createVirtualRegister(
getRegClass(LLT::scalar(32), DstReg, MRI));
TransitRegTo = TransitRegFrom;
}
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(ZextEntryIt->MovOp))
.addDef(TransitRegTo)
.addReg(SrcReg);
}
if (ZextEntryIt->NeedSubregToReg) {
BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(TargetOpcode::SUBREG_TO_REG))
.addDef(DstReg)
.addImm(0)
.addReg(TransitRegFrom)
.addImm(X86::sub_32bit);
}
I.eraseFromParent();
return true;
}
if (SrcTy != LLT::scalar(1))
return false;
unsigned AndOpc;
if (DstTy == LLT::scalar(8))
AndOpc = X86::AND8ri;
else if (DstTy == LLT::scalar(16))
AndOpc = X86::AND16ri8;
else if (DstTy == LLT::scalar(32))
AndOpc = X86::AND32ri8;
else if (DstTy == LLT::scalar(64))
AndOpc = X86::AND64ri8;
else
return false;
unsigned DefReg = SrcReg;
if (DstTy != LLT::scalar(8)) {
DefReg = MRI.createVirtualRegister(getRegClass(DstTy, DstReg, MRI));
BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(TargetOpcode::SUBREG_TO_REG), DefReg)
.addImm(0)
.addReg(SrcReg)
.addImm(X86::sub_8bit);
}
MachineInstr &AndInst =
*BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(AndOpc), DstReg)
.addReg(DefReg)
.addImm(1);
constrainSelectedInstRegOperands(AndInst, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
bool X86InstructionSelector::selectAnyext(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_ANYEXT) && "unexpected instruction");
const unsigned DstReg = I.getOperand(0).getReg();
const unsigned SrcReg = I.getOperand(1).getReg();
const LLT DstTy = MRI.getType(DstReg);
const LLT SrcTy = MRI.getType(SrcReg);
const RegisterBank &DstRB = *RBI.getRegBank(DstReg, MRI, TRI);
const RegisterBank &SrcRB = *RBI.getRegBank(SrcReg, MRI, TRI);
assert(DstRB.getID() == SrcRB.getID() &&
"G_ANYEXT input/output on different banks\n");
assert(DstTy.getSizeInBits() > SrcTy.getSizeInBits() &&
"G_ANYEXT incorrect operand size");
const TargetRegisterClass *DstRC = getRegClass(DstTy, DstRB);
const TargetRegisterClass *SrcRC = getRegClass(SrcTy, SrcRB);
// If that's ANY_EXT of the value that lives on the floating class and goes
// into the vector class, just replace it with copy, as we are able to select
// it as a regular move.
if (canTurnIntoCOPY(SrcRC, DstRC))
return selectTurnIntoCOPY(I, MRI, SrcReg, SrcRC, DstReg, DstRC);
if (DstRB.getID() != X86::GPRRegBankID)
return false;
if (!RBI.constrainGenericRegister(SrcReg, *SrcRC, MRI) ||
!RBI.constrainGenericRegister(DstReg, *DstRC, MRI)) {
DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())
<< " operand\n");
return false;
}
if (SrcRC == DstRC) {
I.setDesc(TII.get(X86::COPY));
return true;
}
BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(TargetOpcode::SUBREG_TO_REG))
.addDef(DstReg)
.addImm(0)
.addReg(SrcReg)
.addImm(getSubRegIndex(SrcRC));
I.eraseFromParent();
return true;
}
bool X86InstructionSelector::selectCmp(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_ICMP) && "unexpected instruction");
X86::CondCode CC;
bool SwapArgs;
std::tie(CC, SwapArgs) = X86::getX86ConditionCode(
(CmpInst::Predicate)I.getOperand(1).getPredicate());
unsigned OpSet = X86::getSETFromCond(CC);
unsigned LHS = I.getOperand(2).getReg();
unsigned RHS = I.getOperand(3).getReg();
if (SwapArgs)
std::swap(LHS, RHS);
unsigned OpCmp;
LLT Ty = MRI.getType(LHS);
switch (Ty.getSizeInBits()) {
default:
return false;
case 8:
OpCmp = X86::CMP8rr;
break;
case 16:
OpCmp = X86::CMP16rr;
break;
case 32:
OpCmp = X86::CMP32rr;
break;
case 64:
OpCmp = X86::CMP64rr;
break;
}
MachineInstr &CmpInst =
*BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(OpCmp))
.addReg(LHS)
.addReg(RHS);
MachineInstr &SetInst = *BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(OpSet), I.getOperand(0).getReg());
constrainSelectedInstRegOperands(CmpInst, TII, TRI, RBI);
constrainSelectedInstRegOperands(SetInst, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
bool X86InstructionSelector::selectUadde(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_UADDE) && "unexpected instruction");
const unsigned DstReg = I.getOperand(0).getReg();
const unsigned CarryOutReg = I.getOperand(1).getReg();
const unsigned Op0Reg = I.getOperand(2).getReg();
const unsigned Op1Reg = I.getOperand(3).getReg();
unsigned CarryInReg = I.getOperand(4).getReg();
const LLT DstTy = MRI.getType(DstReg);
if (DstTy != LLT::scalar(32))
return false;
// find CarryIn def instruction.
MachineInstr *Def = MRI.getVRegDef(CarryInReg);
while (Def->getOpcode() == TargetOpcode::G_TRUNC) {
CarryInReg = Def->getOperand(1).getReg();
Def = MRI.getVRegDef(CarryInReg);
}
unsigned Opcode;
if (Def->getOpcode() == TargetOpcode::G_UADDE) {
// carry set by prev ADD.
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(X86::COPY), X86::EFLAGS)
.addReg(CarryInReg);
if (!RBI.constrainGenericRegister(CarryInReg, X86::GR32RegClass, MRI))
return false;
Opcode = X86::ADC32rr;
} else if (auto val = getConstantVRegVal(CarryInReg, MRI)) {
// carry is constant, support only 0.
if (*val != 0)
return false;
Opcode = X86::ADD32rr;
} else
return false;
MachineInstr &AddInst =
*BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(Opcode), DstReg)
.addReg(Op0Reg)
.addReg(Op1Reg);
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(X86::COPY), CarryOutReg)
.addReg(X86::EFLAGS);
if (!constrainSelectedInstRegOperands(AddInst, TII, TRI, RBI) ||
!RBI.constrainGenericRegister(CarryOutReg, X86::GR32RegClass, MRI))
return false;
I.eraseFromParent();
return true;
}
bool X86InstructionSelector::selectExtract(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_EXTRACT) &&
"unexpected instruction");
const unsigned DstReg = I.getOperand(0).getReg();
const unsigned SrcReg = I.getOperand(1).getReg();
int64_t Index = I.getOperand(2).getImm();
const LLT DstTy = MRI.getType(DstReg);
const LLT SrcTy = MRI.getType(SrcReg);
// Meanwile handle vector type only.
if (!DstTy.isVector())
return false;
if (Index % DstTy.getSizeInBits() != 0)
return false; // Not extract subvector.
if (Index == 0) {
// Replace by extract subreg copy.
if (!emitExtractSubreg(DstReg, SrcReg, I, MRI, MF))
return false;
I.eraseFromParent();
return true;
}
bool HasAVX = STI.hasAVX();
bool HasAVX512 = STI.hasAVX512();
bool HasVLX = STI.hasVLX();
if (SrcTy.getSizeInBits() == 256 && DstTy.getSizeInBits() == 128) {
if (HasVLX)
I.setDesc(TII.get(X86::VEXTRACTF32x4Z256rr));
else if (HasAVX)
I.setDesc(TII.get(X86::VEXTRACTF128rr));
else
return false;
} else if (SrcTy.getSizeInBits() == 512 && HasAVX512) {
if (DstTy.getSizeInBits() == 128)
I.setDesc(TII.get(X86::VEXTRACTF32x4Zrr));
else if (DstTy.getSizeInBits() == 256)
I.setDesc(TII.get(X86::VEXTRACTF64x4Zrr));
else
return false;
} else
return false;
// Convert to X86 VEXTRACT immediate.
Index = Index / DstTy.getSizeInBits();
I.getOperand(2).setImm(Index);
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
bool X86InstructionSelector::emitExtractSubreg(unsigned DstReg, unsigned SrcReg,
MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
const LLT DstTy = MRI.getType(DstReg);
const LLT SrcTy = MRI.getType(SrcReg);
unsigned SubIdx = X86::NoSubRegister;
if (!DstTy.isVector() || !SrcTy.isVector())
return false;
assert(SrcTy.getSizeInBits() > DstTy.getSizeInBits() &&
"Incorrect Src/Dst register size");
if (DstTy.getSizeInBits() == 128)
SubIdx = X86::sub_xmm;
else if (DstTy.getSizeInBits() == 256)
SubIdx = X86::sub_ymm;
else
return false;
const TargetRegisterClass *DstRC = getRegClass(DstTy, DstReg, MRI);
const TargetRegisterClass *SrcRC = getRegClass(SrcTy, SrcReg, MRI);
SrcRC = TRI.getSubClassWithSubReg(SrcRC, SubIdx);
if (!RBI.constrainGenericRegister(SrcReg, *SrcRC, MRI) ||
!RBI.constrainGenericRegister(DstReg, *DstRC, MRI)) {
DEBUG(dbgs() << "Failed to constrain G_TRUNC\n");
return false;
}
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(X86::COPY), DstReg)
.addReg(SrcReg, 0, SubIdx);
return true;
}
bool X86InstructionSelector::emitInsertSubreg(unsigned DstReg, unsigned SrcReg,
MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
const LLT DstTy = MRI.getType(DstReg);
const LLT SrcTy = MRI.getType(SrcReg);
unsigned SubIdx = X86::NoSubRegister;
// TODO: support scalar types
if (!DstTy.isVector() || !SrcTy.isVector())
return false;
assert(SrcTy.getSizeInBits() < DstTy.getSizeInBits() &&
"Incorrect Src/Dst register size");
if (SrcTy.getSizeInBits() == 128)
SubIdx = X86::sub_xmm;
else if (SrcTy.getSizeInBits() == 256)
SubIdx = X86::sub_ymm;
else
return false;
const TargetRegisterClass *SrcRC = getRegClass(SrcTy, SrcReg, MRI);
const TargetRegisterClass *DstRC = getRegClass(DstTy, DstReg, MRI);
if (!RBI.constrainGenericRegister(SrcReg, *SrcRC, MRI) ||
!RBI.constrainGenericRegister(DstReg, *DstRC, MRI)) {
DEBUG(dbgs() << "Failed to constrain INSERT_SUBREG\n");
return false;
}
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(X86::COPY))
.addReg(DstReg, RegState::DefineNoRead, SubIdx)
.addReg(SrcReg);
return true;
}
bool X86InstructionSelector::selectInsert(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_INSERT) && "unexpected instruction");
const unsigned DstReg = I.getOperand(0).getReg();
const unsigned SrcReg = I.getOperand(1).getReg();
const unsigned InsertReg = I.getOperand(2).getReg();
int64_t Index = I.getOperand(3).getImm();
const LLT DstTy = MRI.getType(DstReg);
const LLT InsertRegTy = MRI.getType(InsertReg);
// Meanwile handle vector type only.
if (!DstTy.isVector())
return false;
if (Index % InsertRegTy.getSizeInBits() != 0)
return false; // Not insert subvector.
if (Index == 0 && MRI.getVRegDef(SrcReg)->isImplicitDef()) {
// Replace by subreg copy.
if (!emitInsertSubreg(DstReg, InsertReg, I, MRI, MF))
return false;
I.eraseFromParent();
return true;
}
bool HasAVX = STI.hasAVX();
bool HasAVX512 = STI.hasAVX512();
bool HasVLX = STI.hasVLX();
if (DstTy.getSizeInBits() == 256 && InsertRegTy.getSizeInBits() == 128) {
if (HasVLX)
I.setDesc(TII.get(X86::VINSERTF32x4Z256rr));
else if (HasAVX)
I.setDesc(TII.get(X86::VINSERTF128rr));
else
return false;
} else if (DstTy.getSizeInBits() == 512 && HasAVX512) {
if (InsertRegTy.getSizeInBits() == 128)
I.setDesc(TII.get(X86::VINSERTF32x4Zrr));
else if (InsertRegTy.getSizeInBits() == 256)
I.setDesc(TII.get(X86::VINSERTF64x4Zrr));
else
return false;
} else
return false;
// Convert to X86 VINSERT immediate.
Index = Index / InsertRegTy.getSizeInBits();
I.getOperand(3).setImm(Index);
return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
}
bool X86InstructionSelector::selectUnmergeValues(
MachineInstr &I, MachineRegisterInfo &MRI, MachineFunction &MF,
CodeGenCoverage &CoverageInfo) const {
assert((I.getOpcode() == TargetOpcode::G_UNMERGE_VALUES) &&
"unexpected instruction");
// Split to extracts.
unsigned NumDefs = I.getNumOperands() - 1;
unsigned SrcReg = I.getOperand(NumDefs).getReg();
unsigned DefSize = MRI.getType(I.getOperand(0).getReg()).getSizeInBits();
for (unsigned Idx = 0; Idx < NumDefs; ++Idx) {
MachineInstr &ExtrInst =
*BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(TargetOpcode::G_EXTRACT), I.getOperand(Idx).getReg())
.addReg(SrcReg)
.addImm(Idx * DefSize);
if (!select(ExtrInst, CoverageInfo))
return false;
}
I.eraseFromParent();
return true;
}
bool X86InstructionSelector::selectMergeValues(
MachineInstr &I, MachineRegisterInfo &MRI, MachineFunction &MF,
CodeGenCoverage &CoverageInfo) const {
assert((I.getOpcode() == TargetOpcode::G_MERGE_VALUES) &&
"unexpected instruction");
// Split to inserts.
unsigned DstReg = I.getOperand(0).getReg();
unsigned SrcReg0 = I.getOperand(1).getReg();
const LLT DstTy = MRI.getType(DstReg);
const LLT SrcTy = MRI.getType(SrcReg0);
unsigned SrcSize = SrcTy.getSizeInBits();
const RegisterBank &RegBank = *RBI.getRegBank(DstReg, MRI, TRI);
// For the first src use insertSubReg.
unsigned DefReg = MRI.createGenericVirtualRegister(DstTy);
MRI.setRegBank(DefReg, RegBank);
if (!emitInsertSubreg(DefReg, I.getOperand(1).getReg(), I, MRI, MF))
return false;
for (unsigned Idx = 2; Idx < I.getNumOperands(); ++Idx) {
unsigned Tmp = MRI.createGenericVirtualRegister(DstTy);
MRI.setRegBank(Tmp, RegBank);
MachineInstr &InsertInst = *BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(TargetOpcode::G_INSERT), Tmp)
.addReg(DefReg)
.addReg(I.getOperand(Idx).getReg())
.addImm((Idx - 1) * SrcSize);
DefReg = Tmp;
if (!select(InsertInst, CoverageInfo))
return false;
}
MachineInstr &CopyInst = *BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(TargetOpcode::COPY), DstReg)
.addReg(DefReg);
if (!select(CopyInst, CoverageInfo))
return false;
I.eraseFromParent();
return true;
}
bool X86InstructionSelector::selectCondBranch(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_BRCOND) && "unexpected instruction");
const unsigned CondReg = I.getOperand(0).getReg();
MachineBasicBlock *DestMBB = I.getOperand(1).getMBB();
MachineInstr &TestInst =
*BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(X86::TEST8ri))
.addReg(CondReg)
.addImm(1);
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(X86::JNE_1))
.addMBB(DestMBB);
constrainSelectedInstRegOperands(TestInst, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
bool X86InstructionSelector::materializeFP(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_FCONSTANT) &&
"unexpected instruction");
// Can't handle alternate code models yet.
CodeModel::Model CM = TM.getCodeModel();
if (CM != CodeModel::Small && CM != CodeModel::Large)
return false;
const unsigned DstReg = I.getOperand(0).getReg();
const LLT DstTy = MRI.getType(DstReg);
const RegisterBank &RegBank = *RBI.getRegBank(DstReg, MRI, TRI);
unsigned Align = DstTy.getSizeInBits();
const DebugLoc &DbgLoc = I.getDebugLoc();
unsigned Opc = getLoadStoreOp(DstTy, RegBank, TargetOpcode::G_LOAD, Align);
// Create the load from the constant pool.
const ConstantFP *CFP = I.getOperand(1).getFPImm();
unsigned CPI = MF.getConstantPool()->getConstantPoolIndex(CFP, Align);
MachineInstr *LoadInst = nullptr;
unsigned char OpFlag = STI.classifyLocalReference(nullptr);
if (CM == CodeModel::Large && STI.is64Bit()) {
// Under X86-64 non-small code model, GV (and friends) are 64-bits, so
// they cannot be folded into immediate fields.
unsigned AddrReg = MRI.createVirtualRegister(&X86::GR64RegClass);
BuildMI(*I.getParent(), I, DbgLoc, TII.get(X86::MOV64ri), AddrReg)
.addConstantPoolIndex(CPI, 0, OpFlag);
MachineMemOperand *MMO = MF.getMachineMemOperand(
MachinePointerInfo::getConstantPool(MF), MachineMemOperand::MOLoad,
MF.getDataLayout().getPointerSize(), Align);
LoadInst =
addDirectMem(BuildMI(*I.getParent(), I, DbgLoc, TII.get(Opc), DstReg),
AddrReg)
.addMemOperand(MMO);
} else if (CM == CodeModel::Small || !STI.is64Bit()) {
// Handle the case when globals fit in our immediate field.
// This is true for X86-32 always and X86-64 when in -mcmodel=small mode.
// x86-32 PIC requires a PIC base register for constant pools.
unsigned PICBase = 0;
if (OpFlag == X86II::MO_PIC_BASE_OFFSET || OpFlag == X86II::MO_GOTOFF) {
// PICBase can be allocated by TII.getGlobalBaseReg(&MF).
// In DAGISEL the code that initialize it generated by the CGBR pass.
return false; // TODO support the mode.
} else if (STI.is64Bit() && TM.getCodeModel() == CodeModel::Small)
PICBase = X86::RIP;
LoadInst = addConstantPoolReference(
BuildMI(*I.getParent(), I, DbgLoc, TII.get(Opc), DstReg), CPI, PICBase,
OpFlag);
} else
return false;
constrainSelectedInstRegOperands(*LoadInst, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
bool X86InstructionSelector::selectImplicitDefOrPHI(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert((I.getOpcode() == TargetOpcode::G_IMPLICIT_DEF ||
I.getOpcode() == TargetOpcode::G_PHI) &&
"unexpected instruction");
unsigned DstReg = I.getOperand(0).getReg();
if (!MRI.getRegClassOrNull(DstReg)) {
const LLT DstTy = MRI.getType(DstReg);
const TargetRegisterClass *RC = getRegClass(DstTy, DstReg, MRI);
if (!RBI.constrainGenericRegister(DstReg, *RC, MRI)) {
DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())
<< " operand\n");
return false;
}
}
if (I.getOpcode() == TargetOpcode::G_IMPLICIT_DEF)
I.setDesc(TII.get(X86::IMPLICIT_DEF));
else
I.setDesc(TII.get(X86::PHI));
return true;
}
// Currently GlobalIsel TableGen generates patterns for shift imm and shift 1,
// but with shiftCount i8. In G_LSHR/G_ASHR/G_SHL like LLVM-IR both arguments
// has the same type, so for now only shift i8 can use auto generated
// TableGen patterns.
bool X86InstructionSelector::selectShift(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_SHL ||
I.getOpcode() == TargetOpcode::G_ASHR ||
I.getOpcode() == TargetOpcode::G_LSHR) &&
"unexpected instruction");
unsigned DstReg = I.getOperand(0).getReg();
const LLT DstTy = MRI.getType(DstReg);
const RegisterBank &DstRB = *RBI.getRegBank(DstReg, MRI, TRI);
const static struct ShiftEntry {
unsigned SizeInBits;
unsigned CReg;
unsigned OpLSHR;
unsigned OpASHR;
unsigned OpSHL;
} OpTable[] = {
{8, X86::CL, X86::SHR8rCL, X86::SAR8rCL, X86::SHL8rCL}, // i8
{16, X86::CX, X86::SHR16rCL, X86::SAR16rCL, X86::SHL16rCL}, // i16
{32, X86::ECX, X86::SHR32rCL, X86::SAR32rCL, X86::SHL32rCL}, // i32
{64, X86::RCX, X86::SHR64rCL, X86::SAR64rCL, X86::SHL64rCL} // i64
};
if (DstRB.getID() != X86::GPRRegBankID)
return false;
auto ShiftEntryIt = std::find_if(
std::begin(OpTable), std::end(OpTable), [DstTy](const ShiftEntry &El) {
return El.SizeInBits == DstTy.getSizeInBits();
});
if (ShiftEntryIt == std::end(OpTable))
return false;
unsigned CReg = ShiftEntryIt->CReg;
unsigned Opcode = 0;
switch (I.getOpcode()) {
case TargetOpcode::G_SHL:
Opcode = ShiftEntryIt->OpSHL;
break;
case TargetOpcode::G_ASHR:
Opcode = ShiftEntryIt->OpASHR;
break;
case TargetOpcode::G_LSHR:
Opcode = ShiftEntryIt->OpLSHR;
break;
default:
return false;
}
unsigned Op0Reg = I.getOperand(1).getReg();
unsigned Op1Reg = I.getOperand(2).getReg();
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(TargetOpcode::COPY),
ShiftEntryIt->CReg)
.addReg(Op1Reg);
// The shift instruction uses X86::CL. If we defined a super-register
// of X86::CL, emit a subreg KILL to precisely describe what we're doing here.
if (CReg != X86::CL)
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(TargetOpcode::KILL),
X86::CL)
.addReg(CReg, RegState::Kill);
MachineInstr &ShiftInst =
*BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(Opcode), DstReg)
.addReg(Op0Reg);
constrainSelectedInstRegOperands(ShiftInst, TII, TRI, RBI);
I.eraseFromParent();
return true;
}
bool X86InstructionSelector::selectSDiv(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert(I.getOpcode() == TargetOpcode::G_SDIV && "unexpected instruction");
const unsigned DstReg = I.getOperand(0).getReg();
const unsigned DividentReg = I.getOperand(1).getReg();
const unsigned DiviserReg = I.getOperand(2).getReg();
const LLT RegTy = MRI.getType(DstReg);
assert(RegTy == MRI.getType(DividentReg) &&
RegTy == MRI.getType(DiviserReg) &&
"Arguments and return value types must match");
const RegisterBank &RegRB = *RBI.getRegBank(DstReg, MRI, TRI);
// For the X86 IDIV instruction, in most cases the dividend
// (numerator) must be in a specific register pair highreg:lowreg,
// producing the quotient in lowreg and the remainder in highreg.
// For most data types, to set up the instruction, the dividend is
// copied into lowreg, and lowreg is sign-extended into highreg. The
// exception is i8, where the dividend is defined as a single register rather
// than a register pair, and we therefore directly sign-extend the dividend
// into lowreg, instead of copying, and ignore the highreg.
const static struct SDivEntry {
unsigned SizeInBits;
unsigned QuotientReg;
unsigned DividentRegUpper;
unsigned DividentRegLower;
unsigned OpSignExtend;
unsigned OpCopy;
unsigned OpDiv;
} OpTable[] = {
{8, X86::AL, X86::NoRegister, X86::AX, 0, X86::MOVSX16rr8,
X86::IDIV8r}, // i8
{16, X86::AX, X86::DX, X86::AX, X86::CWD, TargetOpcode::COPY,
X86::IDIV16r}, // i16
{32, X86::EAX, X86::EDX, X86::EAX, X86::CDQ, TargetOpcode::COPY,
X86::IDIV32r}, // i32
{64, X86::RAX, X86::RDX, X86::RAX, X86::CQO, TargetOpcode::COPY,
X86::IDIV64r} // i64
};
if (RegRB.getID() != X86::GPRRegBankID)
return false;
auto SDivEntryIt = std::find_if(
std::begin(OpTable), std::end(OpTable), [RegTy](const SDivEntry &El) {
return El.SizeInBits == RegTy.getSizeInBits();
});
if (SDivEntryIt == std::end(OpTable))
return false;
const TargetRegisterClass *RegRC = getRegClass(RegTy, RegRB);
if (!RBI.constrainGenericRegister(DividentReg, *RegRC, MRI) ||
!RBI.constrainGenericRegister(DiviserReg, *RegRC, MRI) ||
!RBI.constrainGenericRegister(DstReg, *RegRC, MRI)) {
DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())
<< " operand\n");
return false;
}
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(SDivEntryIt->OpCopy),
SDivEntryIt->DividentRegLower)
.addReg(DividentReg);
if (SDivEntryIt->DividentRegUpper != X86::NoRegister)
BuildMI(*I.getParent(), I, I.getDebugLoc(),
TII.get(SDivEntryIt->OpSignExtend));
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(SDivEntryIt->OpDiv))
.addReg(DiviserReg);
BuildMI(*I.getParent(), I, I.getDebugLoc(), TII.get(TargetOpcode::COPY),
DstReg)
.addReg(SDivEntryIt->QuotientReg);
I.eraseFromParent();
return true;
}
InstructionSelector *
llvm::createX86InstructionSelector(const X86TargetMachine &TM,
X86Subtarget &Subtarget,
X86RegisterBankInfo &RBI) {
return new X86InstructionSelector(TM, Subtarget, RBI);
}
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