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llvm-project/llvm/lib/Target/X86/X86InstructionSelector.cpp
David Blaikie b3bde2ea50 Fix a bunch more layering of CodeGen headers that are in Target 
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).

llvm-svn: 318490
2017-11-17 01:07:10 +00:00

1294 lines
44 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 selectTrunc(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 materializeFP(MachineInstr &I, MachineRegisterInfo &MRI,
MachineFunction &MF) const;
bool selectImplicitDefOrPHI(MachineInstr &I, MachineRegisterInfo &MRI) 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_TRUNC:
return selectTrunc(I, MRI, MF);
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);
}
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);
}
bool X86InstructionSelector::selectTrunc(MachineInstr &I,
MachineRegisterInfo &MRI,
MachineFunction &MF) const {
assert((I.getOpcode() == TargetOpcode::G_TRUNC) && "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() << "G_TRUNC input/output on different banks\n");
return false;
}
if (DstRB.getID() != X86::GPRRegBankID)
return false;
const TargetRegisterClass *DstRC = getRegClass(DstTy, DstRB);
if (!DstRC)
return false;
const TargetRegisterClass *SrcRC = getRegClass(SrcTy, SrcRB);
if (!SrcRC)
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 G_TRUNC\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);
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");
if (DstRB.getID() != X86::GPRRegBankID)
return false;
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;
}
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;
}
InstructionSelector *
llvm::createX86InstructionSelector(const X86TargetMachine &TM,
X86Subtarget &Subtarget,
X86RegisterBankInfo &RBI) {
return new X86InstructionSelector(TM, Subtarget, RBI);
}
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