//===-- SystemZInstrInfo.cpp - SystemZ instruction information ------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the SystemZ implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "SystemZInstrInfo.h"
#include "SystemZInstrBuilder.h"
#include "SystemZTargetMachine.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
using namespace llvm;
#define GET_INSTRINFO_CTOR_DTOR
#define GET_INSTRMAP_INFO
#include "SystemZGenInstrInfo.inc"
// Return a mask with Count low bits set.
static uint64_t allOnes(unsigned int Count) {
return Count == 0 ? 0 : (uint64_t(1) << (Count - 1) << 1) - 1;
}
// Reg should be a 32-bit GPR. Return true if it is a high register rather
// than a low register.
static bool isHighReg(unsigned int Reg) {
if (SystemZ::GRH32BitRegClass.contains(Reg))
return true;
assert(SystemZ::GR32BitRegClass.contains(Reg) && "Invalid GRX32");
return false;
}
// Pin the vtable to this file.
void SystemZInstrInfo::anchor() {}
SystemZInstrInfo::SystemZInstrInfo(SystemZSubtarget &sti)
: SystemZGenInstrInfo(SystemZ::ADJCALLSTACKDOWN, SystemZ::ADJCALLSTACKUP),
RI(), STI(sti) {
}
// MI is a 128-bit load or store. Split it into two 64-bit loads or stores,
// each having the opcode given by NewOpcode.
void SystemZInstrInfo::splitMove(MachineBasicBlock::iterator MI,
unsigned NewOpcode) const {
MachineBasicBlock *MBB = MI->getParent();
MachineFunction &MF = *MBB->getParent();
// Get two load or store instructions. Use the original instruction for one
// of them (arbitrarily the second here) and create a clone for the other.
MachineInstr *EarlierMI = MF.CloneMachineInstr(MI);
MBB->insert(MI, EarlierMI);
// Set up the two 64-bit registers.
MachineOperand &HighRegOp = EarlierMI->getOperand(0);
MachineOperand &LowRegOp = MI->getOperand(0);
HighRegOp.setReg(RI.getSubReg(HighRegOp.getReg(), SystemZ::subreg_h64));
LowRegOp.setReg(RI.getSubReg(LowRegOp.getReg(), SystemZ::subreg_l64));
// The address in the first (high) instruction is already correct.
// Adjust the offset in the second (low) instruction.
MachineOperand &HighOffsetOp = EarlierMI->getOperand(2);
MachineOperand &LowOffsetOp = MI->getOperand(2);
LowOffsetOp.setImm(LowOffsetOp.getImm() + 8);
// Set the opcodes.
unsigned HighOpcode = getOpcodeForOffset(NewOpcode, HighOffsetOp.getImm());
unsigned LowOpcode = getOpcodeForOffset(NewOpcode, LowOffsetOp.getImm());
assert(HighOpcode && LowOpcode && "Both offsets should be in range");
EarlierMI->setDesc(get(HighOpcode));
MI->setDesc(get(LowOpcode));
}
// Split ADJDYNALLOC instruction MI.
void SystemZInstrInfo::splitAdjDynAlloc(MachineBasicBlock::iterator MI) const {
MachineBasicBlock *MBB = MI->getParent();
MachineFunction &MF = *MBB->getParent();
MachineFrameInfo *MFFrame = MF.getFrameInfo();
MachineOperand &OffsetMO = MI->getOperand(2);
uint64_t Offset = (MFFrame->getMaxCallFrameSize() +
SystemZMC::CallFrameSize +
OffsetMO.getImm());
unsigned NewOpcode = getOpcodeForOffset(SystemZ::LA, Offset);
assert(NewOpcode && "No support for huge argument lists yet");
MI->setDesc(get(NewOpcode));
OffsetMO.setImm(Offset);
}
// MI is an RI-style pseudo instruction. Replace it with LowOpcode
// if the first operand is a low GR32 and HighOpcode if the first operand
// is a high GR32. ConvertHigh is true if LowOpcode takes a signed operand
// and HighOpcode takes an unsigned 32-bit operand. In those cases,
// MI has the same kind of operand as LowOpcode, so needs to be converted
// if HighOpcode is used.
void SystemZInstrInfo::expandRIPseudo(MachineInstr *MI, unsigned LowOpcode,
unsigned HighOpcode,
bool ConvertHigh) const {
unsigned Reg = MI->getOperand(0).getReg();
bool IsHigh = isHighReg(Reg);
MI->setDesc(get(IsHigh ? HighOpcode : LowOpcode));
if (IsHigh && ConvertHigh)
MI->getOperand(1).setImm(uint32_t(MI->getOperand(1).getImm()));
}
// MI is a three-operand RIE-style pseudo instruction. Replace it with
// LowOpcode3 if the registers are both low GR32s, otherwise use a move
// followed by HighOpcode or LowOpcode, depending on whether the target
// is a high or low GR32.
void SystemZInstrInfo::expandRIEPseudo(MachineInstr *MI, unsigned LowOpcode,
unsigned LowOpcodeK,
unsigned HighOpcode) const {
unsigned DestReg = MI->getOperand(0).getReg();
unsigned SrcReg = MI->getOperand(1).getReg();
bool DestIsHigh = isHighReg(DestReg);
bool SrcIsHigh = isHighReg(SrcReg);
if (!DestIsHigh && !SrcIsHigh)
MI->setDesc(get(LowOpcodeK));
else {
emitGRX32Move(*MI->getParent(), MI, MI->getDebugLoc(),
DestReg, SrcReg, SystemZ::LR, 32,
MI->getOperand(1).isKill());
MI->setDesc(get(DestIsHigh ? HighOpcode : LowOpcode));
MI->getOperand(1).setReg(DestReg);
}
}
// MI is an RXY-style pseudo instruction. Replace it with LowOpcode
// if the first operand is a low GR32 and HighOpcode if the first operand
// is a high GR32.
void SystemZInstrInfo::expandRXYPseudo(MachineInstr *MI, unsigned LowOpcode,
unsigned HighOpcode) const {
unsigned Reg = MI->getOperand(0).getReg();
unsigned Opcode = getOpcodeForOffset(isHighReg(Reg) ? HighOpcode : LowOpcode,
MI->getOperand(2).getImm());
MI->setDesc(get(Opcode));
}
// MI is an RR-style pseudo instruction that zero-extends the low Size bits
// of one GRX32 into another. Replace it with LowOpcode if both operands
// are low registers, otherwise use RISB[LH]G.
void SystemZInstrInfo::expandZExtPseudo(MachineInstr *MI, unsigned LowOpcode,
unsigned Size) const {
emitGRX32Move(*MI->getParent(), MI, MI->getDebugLoc(),
MI->getOperand(0).getReg(), MI->getOperand(1).getReg(),
LowOpcode, Size, MI->getOperand(1).isKill());
MI->eraseFromParent();
}
// Emit a zero-extending move from 32-bit GPR SrcReg to 32-bit GPR
// DestReg before MBBI in MBB. Use LowLowOpcode when both DestReg and SrcReg
// are low registers, otherwise use RISB[LH]G. Size is the number of bits
// taken from the low end of SrcReg (8 for LLCR, 16 for LLHR and 32 for LR).
// KillSrc is true if this move is the last use of SrcReg.
void SystemZInstrInfo::emitGRX32Move(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
DebugLoc DL, unsigned DestReg,
unsigned SrcReg, unsigned LowLowOpcode,
unsigned Size, bool KillSrc) const {
unsigned Opcode;
bool DestIsHigh = isHighReg(DestReg);
bool SrcIsHigh = isHighReg(SrcReg);
if (DestIsHigh && SrcIsHigh)
Opcode = SystemZ::RISBHH;
else if (DestIsHigh && !SrcIsHigh)
Opcode = SystemZ::RISBHL;
else if (!DestIsHigh && SrcIsHigh)
Opcode = SystemZ::RISBLH;
else {
BuildMI(MBB, MBBI, DL, get(LowLowOpcode), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
return;
}
unsigned Rotate = (DestIsHigh != SrcIsHigh ? 32 : 0);
BuildMI(MBB, MBBI, DL, get(Opcode), DestReg)
.addReg(DestReg, RegState::Undef)
.addReg(SrcReg, getKillRegState(KillSrc))
.addImm(32 - Size).addImm(128 + 31).addImm(Rotate);
}
// If MI is a simple load or store for a frame object, return the register
// it loads or stores and set FrameIndex to the index of the frame object.
// Return 0 otherwise.
//
// Flag is SimpleBDXLoad for loads and SimpleBDXStore for stores.
static int isSimpleMove(const MachineInstr *MI, int &FrameIndex,
unsigned Flag) {
const MCInstrDesc &MCID = MI->getDesc();
if ((MCID.TSFlags & Flag) &&
MI->getOperand(1).isFI() &&
MI->getOperand(2).getImm() == 0 &&
MI->getOperand(3).getReg() == 0) {
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
return 0;
}
unsigned SystemZInstrInfo::isLoadFromStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
return isSimpleMove(MI, FrameIndex, SystemZII::SimpleBDXLoad);
}
unsigned SystemZInstrInfo::isStoreToStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
return isSimpleMove(MI, FrameIndex, SystemZII::SimpleBDXStore);
}
bool SystemZInstrInfo::isStackSlotCopy(const MachineInstr *MI,
int &DestFrameIndex,
int &SrcFrameIndex) const {
// Check for MVC 0(Length,FI1),0(FI2)
const MachineFrameInfo *MFI = MI->getParent()->getParent()->getFrameInfo();
if (MI->getOpcode() != SystemZ::MVC ||
!MI->getOperand(0).isFI() ||
MI->getOperand(1).getImm() != 0 ||
!MI->getOperand(3).isFI() ||
MI->getOperand(4).getImm() != 0)
return false;
// Check that Length covers the full slots.
int64_t Length = MI->getOperand(2).getImm();
unsigned FI1 = MI->getOperand(0).getIndex();
unsigned FI2 = MI->getOperand(3).getIndex();
if (MFI->getObjectSize(FI1) != Length ||
MFI->getObjectSize(FI2) != Length)
return false;
DestFrameIndex = FI1;
SrcFrameIndex = FI2;
return true;
}
bool SystemZInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,
MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify) const {
// Most of the code and comments here are boilerplate.
// Start from the bottom of the block and work up, examining the
// terminator instructions.
MachineBasicBlock::iterator I = MBB.end();
while (I != MBB.begin()) {
--I;
if (I->isDebugValue())
continue;
// Working from the bottom, when we see a non-terminator instruction, we're
// done.
if (!isUnpredicatedTerminator(I))
break;
// A terminator that isn't a branch can't easily be handled by this
// analysis.
if (!I->isBranch())
return true;
// Can't handle indirect branches.
SystemZII::Branch Branch(getBranchInfo(I));
if (!Branch.Target->isMBB())
return true;
// Punt on compound branches.
if (Branch.Type != SystemZII::BranchNormal)
return true;
if (Branch.CCMask == SystemZ::CCMASK_ANY) {
// Handle unconditional branches.
if (!AllowModify) {
TBB = Branch.Target->getMBB();
continue;
}
// If the block has any instructions after a JMP, delete them.
while (std::next(I) != MBB.end())
std::next(I)->eraseFromParent();
Cond.clear();
FBB = nullptr;
// Delete the JMP if it's equivalent to a fall-through.
if (MBB.isLayoutSuccessor(Branch.Target->getMBB())) {
TBB = nullptr;
I->eraseFromParent();
I = MBB.end();
continue;
}
// TBB is used to indicate the unconditinal destination.
TBB = Branch.Target->getMBB();
continue;
}
// Working from the bottom, handle the first conditional branch.
if (Cond.empty()) {
// FIXME: add X86-style branch swap
FBB = TBB;
TBB = Branch.Target->getMBB();
Cond.push_back(MachineOperand::CreateImm(Branch.CCValid));
Cond.push_back(MachineOperand::CreateImm(Branch.CCMask));
continue;
}
// Handle subsequent conditional branches.
assert(Cond.size() == 2 && TBB && "Should have seen a conditional branch");
// Only handle the case where all conditional branches branch to the same
// destination.
if (TBB != Branch.Target->getMBB())
return true;
// If the conditions are the same, we can leave them alone.
unsigned OldCCValid = Cond[0].getImm();
unsigned OldCCMask = Cond[1].getImm();
if (OldCCValid == Branch.CCValid && OldCCMask == Branch.CCMask)
continue;
// FIXME: Try combining conditions like X86 does. Should be easy on Z!
return false;
}
return false;
}
unsigned SystemZInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
// Most of the code and comments here are boilerplate.
MachineBasicBlock::iterator I = MBB.end();
unsigned Count = 0;
while (I != MBB.begin()) {
--I;
if (I->isDebugValue())
continue;
if (!I->isBranch())
break;
if (!getBranchInfo(I).Target->isMBB())
break;
// Remove the branch.
I->eraseFromParent();
I = MBB.end();
++Count;
}
return Count;
}
bool SystemZInstrInfo::
ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const {
assert(Cond.size() == 2 && "Invalid condition");
Cond[1].setImm(Cond[1].getImm() ^ Cond[0].getImm());
return false;
}
unsigned
SystemZInstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond,
DebugLoc DL) const {
// In this function we output 32-bit branches, which should always
// have enough range. They can be shortened and relaxed by later code
// in the pipeline, if desired.
// Shouldn't be a fall through.
assert(TBB && "InsertBranch must not be told to insert a fallthrough");
assert((Cond.size() == 2 || Cond.size() == 0) &&
"SystemZ branch conditions have one component!");
if (Cond.empty()) {
// Unconditional branch?
assert(!FBB && "Unconditional branch with multiple successors!");
BuildMI(&MBB, DL, get(SystemZ::J)).addMBB(TBB);
return 1;
}
// Conditional branch.
unsigned Count = 0;
unsigned CCValid = Cond[0].getImm();
unsigned CCMask = Cond[1].getImm();
BuildMI(&MBB, DL, get(SystemZ::BRC))
.addImm(CCValid).addImm(CCMask).addMBB(TBB);
++Count;
if (FBB) {
// Two-way Conditional branch. Insert the second branch.
BuildMI(&MBB, DL, get(SystemZ::J)).addMBB(FBB);
++Count;
}
return Count;
}
bool SystemZInstrInfo::analyzeCompare(const MachineInstr *MI,
unsigned &SrcReg, unsigned &SrcReg2,
int &Mask, int &Value) const {
assert(MI->isCompare() && "Caller should have checked for a comparison");
if (MI->getNumExplicitOperands() == 2 &&
MI->getOperand(0).isReg() &&
MI->getOperand(1).isImm()) {
SrcReg = MI->getOperand(0).getReg();
SrcReg2 = 0;
Value = MI->getOperand(1).getImm();
Mask = ~0;
return true;
}
return false;
}
// If Reg is a virtual register, return its definition, otherwise return null.
static MachineInstr *getDef(unsigned Reg,
const MachineRegisterInfo *MRI) {
if (TargetRegisterInfo::isPhysicalRegister(Reg))
return nullptr;
return MRI->getUniqueVRegDef(Reg);
}
// Return true if MI is a shift of type Opcode by Imm bits.
static bool isShift(MachineInstr *MI, int Opcode, int64_t Imm) {
return (MI->getOpcode() == Opcode &&
!MI->getOperand(2).getReg() &&
MI->getOperand(3).getImm() == Imm);
}
// If the destination of MI has no uses, delete it as dead.
static void eraseIfDead(MachineInstr *MI, const MachineRegisterInfo *MRI) {
if (MRI->use_nodbg_empty(MI->getOperand(0).getReg()))
MI->eraseFromParent();
}
// Compare compares SrcReg against zero. Check whether SrcReg contains
// the result of an IPM sequence whose input CC survives until Compare,
// and whether Compare is therefore redundant. Delete it and return
// true if so.
static bool removeIPMBasedCompare(MachineInstr *Compare, unsigned SrcReg,
const MachineRegisterInfo *MRI,
const TargetRegisterInfo *TRI) {
MachineInstr *LGFR = nullptr;
MachineInstr *RLL = getDef(SrcReg, MRI);
if (RLL && RLL->getOpcode() == SystemZ::LGFR) {
LGFR = RLL;
RLL = getDef(LGFR->getOperand(1).getReg(), MRI);
}
if (!RLL || !isShift(RLL, SystemZ::RLL, 31))
return false;
MachineInstr *SRL = getDef(RLL->getOperand(1).getReg(), MRI);
if (!SRL || !isShift(SRL, SystemZ::SRL, SystemZ::IPM_CC))
return false;
MachineInstr *IPM = getDef(SRL->getOperand(1).getReg(), MRI);
if (!IPM || IPM->getOpcode() != SystemZ::IPM)
return false;
// Check that there are no assignments to CC between the IPM and Compare,
if (IPM->getParent() != Compare->getParent())
return false;
MachineBasicBlock::iterator MBBI = IPM, MBBE = Compare;
for (++MBBI; MBBI != MBBE; ++MBBI) {
MachineInstr *MI = MBBI;
if (MI->modifiesRegister(SystemZ::CC, TRI))
return false;
}
Compare->eraseFromParent();
if (LGFR)
eraseIfDead(LGFR, MRI);
eraseIfDead(RLL, MRI);
eraseIfDead(SRL, MRI);
eraseIfDead(IPM, MRI);
return true;
}
bool
SystemZInstrInfo::optimizeCompareInstr(MachineInstr *Compare,
unsigned SrcReg, unsigned SrcReg2,
int Mask, int Value,
const MachineRegisterInfo *MRI) const {
assert(!SrcReg2 && "Only optimizing constant comparisons so far");
bool IsLogical = (Compare->getDesc().TSFlags & SystemZII::IsLogical) != 0;
if (Value == 0 &&
!IsLogical &&
removeIPMBasedCompare(Compare, SrcReg, MRI, &RI))
return true;
return false;
}
// If Opcode is a move that has a conditional variant, return that variant,
// otherwise return 0.
static unsigned getConditionalMove(unsigned Opcode) {
switch (Opcode) {
case SystemZ::LR: return SystemZ::LOCR;
case SystemZ::LGR: return SystemZ::LOCGR;
default: return 0;
}
}
bool SystemZInstrInfo::isPredicable(MachineInstr *MI) const {
unsigned Opcode = MI->getOpcode();
if (STI.hasLoadStoreOnCond() &&
getConditionalMove(Opcode))
return true;
return false;
}
bool SystemZInstrInfo::
isProfitableToIfCvt(MachineBasicBlock &MBB,
unsigned NumCycles, unsigned ExtraPredCycles,
const BranchProbability &Probability) const {
// For now only convert single instructions.
return NumCycles == 1;
}
bool SystemZInstrInfo::
isProfitableToIfCvt(MachineBasicBlock &TMBB,
unsigned NumCyclesT, unsigned ExtraPredCyclesT,
MachineBasicBlock &FMBB,
unsigned NumCyclesF, unsigned ExtraPredCyclesF,
const BranchProbability &Probability) const {
// For now avoid converting mutually-exclusive cases.
return false;
}
bool SystemZInstrInfo::
PredicateInstruction(MachineInstr *MI,
const SmallVectorImpl<MachineOperand> &Pred) const {
assert(Pred.size() == 2 && "Invalid condition");
unsigned CCValid = Pred[0].getImm();
unsigned CCMask = Pred[1].getImm();
assert(CCMask > 0 && CCMask < 15 && "Invalid predicate");
unsigned Opcode = MI->getOpcode();
if (STI.hasLoadStoreOnCond()) {
if (unsigned CondOpcode = getConditionalMove(Opcode)) {
MI->setDesc(get(CondOpcode));
MachineInstrBuilder(*MI->getParent()->getParent(), MI)
.addImm(CCValid).addImm(CCMask)
.addReg(SystemZ::CC, RegState::Implicit);
return true;
}
}
return false;
}
void
SystemZInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, DebugLoc DL,
unsigned DestReg, unsigned SrcReg,
bool KillSrc) const {
// Split 128-bit GPR moves into two 64-bit moves. This handles ADDR128 too.
if (SystemZ::GR128BitRegClass.contains(DestReg, SrcReg)) {
copyPhysReg(MBB, MBBI, DL, RI.getSubReg(DestReg, SystemZ::subreg_h64),
RI.getSubReg(SrcReg, SystemZ::subreg_h64), KillSrc);
copyPhysReg(MBB, MBBI, DL, RI.getSubReg(DestReg, SystemZ::subreg_l64),
RI.getSubReg(SrcReg, SystemZ::subreg_l64), KillSrc);
return;
}
if (SystemZ::GRX32BitRegClass.contains(DestReg, SrcReg)) {
emitGRX32Move(MBB, MBBI, DL, DestReg, SrcReg, SystemZ::LR, 32, KillSrc);
return;
}
// Everything else needs only one instruction.
unsigned Opcode;
if (SystemZ::GR64BitRegClass.contains(DestReg, SrcReg))
Opcode = SystemZ::LGR;
else if (SystemZ::FP32BitRegClass.contains(DestReg, SrcReg))
Opcode = SystemZ::LER;
else if (SystemZ::FP64BitRegClass.contains(DestReg, SrcReg))
Opcode = SystemZ::LDR;
else if (SystemZ::FP128BitRegClass.contains(DestReg, SrcReg))
Opcode = SystemZ::LXR;
else
llvm_unreachable("Impossible reg-to-reg copy");
BuildMI(MBB, MBBI, DL, get(Opcode), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
}
void
SystemZInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned SrcReg, bool isKill,
int FrameIdx,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const {
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
// Callers may expect a single instruction, so keep 128-bit moves
// together for now and lower them after register allocation.
unsigned LoadOpcode, StoreOpcode;
getLoadStoreOpcodes(RC, LoadOpcode, StoreOpcode);
addFrameReference(BuildMI(MBB, MBBI, DL, get(StoreOpcode))
.addReg(SrcReg, getKillRegState(isKill)), FrameIdx);
}
void
SystemZInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned DestReg, int FrameIdx,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const {
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
// Callers may expect a single instruction, so keep 128-bit moves
// together for now and lower them after register allocation.
unsigned LoadOpcode, StoreOpcode;
getLoadStoreOpcodes(RC, LoadOpcode, StoreOpcode);
addFrameReference(BuildMI(MBB, MBBI, DL, get(LoadOpcode), DestReg),
FrameIdx);
}
// Return true if MI is a simple load or store with a 12-bit displacement
// and no index. Flag is SimpleBDXLoad for loads and SimpleBDXStore for stores.
static bool isSimpleBD12Move(const MachineInstr *MI, unsigned Flag) {
const MCInstrDesc &MCID = MI->getDesc();
return ((MCID.TSFlags & Flag) &&
isUInt<12>(MI->getOperand(2).getImm()) &&
MI->getOperand(3).getReg() == 0);
}
namespace {
struct LogicOp {
LogicOp() : RegSize(0), ImmLSB(0), ImmSize(0) {}
LogicOp(unsigned regSize, unsigned immLSB, unsigned immSize)
: RegSize(regSize), ImmLSB(immLSB), ImmSize(immSize) {}
explicit operator bool() const { return RegSize; }
unsigned RegSize, ImmLSB, ImmSize;
};
} // end anonymous namespace
static LogicOp interpretAndImmediate(unsigned Opcode) {
switch (Opcode) {
case SystemZ::NILMux: return LogicOp(32, 0, 16);
case SystemZ::NIHMux: return LogicOp(32, 16, 16);
case SystemZ::NILL64: return LogicOp(64, 0, 16);
case SystemZ::NILH64: return LogicOp(64, 16, 16);
case SystemZ::NIHL64: return LogicOp(64, 32, 16);
case SystemZ::NIHH64: return LogicOp(64, 48, 16);
case SystemZ::NIFMux: return LogicOp(32, 0, 32);
case SystemZ::NILF64: return LogicOp(64, 0, 32);
case SystemZ::NIHF64: return LogicOp(64, 32, 32);
default: return LogicOp();
}
}
// Used to return from convertToThreeAddress after replacing two-address
// instruction OldMI with three-address instruction NewMI.
static MachineInstr *finishConvertToThreeAddress(MachineInstr *OldMI,
MachineInstr *NewMI,
LiveVariables *LV) {
if (LV) {
unsigned NumOps = OldMI->getNumOperands();
for (unsigned I = 1; I < NumOps; ++I) {
MachineOperand &Op = OldMI->getOperand(I);
if (Op.isReg() && Op.isKill())
LV->replaceKillInstruction(Op.getReg(), OldMI, NewMI);
}
}
return NewMI;
}
MachineInstr *
SystemZInstrInfo::convertToThreeAddress(MachineFunction::iterator &MFI,
MachineBasicBlock::iterator &MBBI,
LiveVariables *LV) const {
MachineInstr *MI = MBBI;
MachineBasicBlock *MBB = MI->getParent();
MachineRegisterInfo &MRI = MBB->getParent()->getRegInfo();
unsigned Opcode = MI->getOpcode();
unsigned NumOps = MI->getNumOperands();
// Try to convert something like SLL into SLLK, if supported.
// We prefer to keep the two-operand form where possible both
// because it tends to be shorter and because some instructions
// have memory forms that can be used during spilling.
if (STI.hasDistinctOps()) {
MachineOperand &Dest = MI->getOperand(0);
MachineOperand &Src = MI->getOperand(1);
unsigned DestReg = Dest.getReg();
unsigned SrcReg = Src.getReg();
// AHIMux is only really a three-operand instruction when both operands
// are low registers. Try to constrain both operands to be low if
// possible.
if (Opcode == SystemZ::AHIMux &&
TargetRegisterInfo::isVirtualRegister(DestReg) &&
TargetRegisterInfo::isVirtualRegister(SrcReg) &&
MRI.getRegClass(DestReg)->contains(SystemZ::R1L) &&
MRI.getRegClass(SrcReg)->contains(SystemZ::R1L)) {
MRI.constrainRegClass(DestReg, &SystemZ::GR32BitRegClass);
MRI.constrainRegClass(SrcReg, &SystemZ::GR32BitRegClass);
}
int ThreeOperandOpcode = SystemZ::getThreeOperandOpcode(Opcode);
if (ThreeOperandOpcode >= 0) {
MachineInstrBuilder MIB =
BuildMI(*MBB, MBBI, MI->getDebugLoc(), get(ThreeOperandOpcode))
.addOperand(Dest);
// Keep the kill state, but drop the tied flag.
MIB.addReg(Src.getReg(), getKillRegState(Src.isKill()), Src.getSubReg());
// Keep the remaining operands as-is.
for (unsigned I = 2; I < NumOps; ++I)
MIB.addOperand(MI->getOperand(I));
return finishConvertToThreeAddress(MI, MIB, LV);
}
}
// Try to convert an AND into an RISBG-type instruction.
if (LogicOp And = interpretAndImmediate(Opcode)) {
uint64_t Imm = MI->getOperand(2).getImm() << And.ImmLSB;
// AND IMMEDIATE leaves the other bits of the register unchanged.
Imm |= allOnes(And.RegSize) & ~(allOnes(And.ImmSize) << And.ImmLSB);
unsigned Start, End;
if (isRxSBGMask(Imm, And.RegSize, Start, End)) {
unsigned NewOpcode;
if (And.RegSize == 64) {
NewOpcode = SystemZ::RISBG;
// Prefer RISBGN if available, since it does not clobber CC.
if (STI.hasMiscellaneousExtensions())
NewOpcode = SystemZ::RISBGN;
} else {
NewOpcode = SystemZ::RISBMux;
Start &= 31;
End &= 31;
}
MachineOperand &Dest = MI->getOperand(0);
MachineOperand &Src = MI->getOperand(1);
MachineInstrBuilder MIB =
BuildMI(*MBB, MI, MI->getDebugLoc(), get(NewOpcode))
.addOperand(Dest).addReg(0)
.addReg(Src.getReg(), getKillRegState(Src.isKill()), Src.getSubReg())
.addImm(Start).addImm(End + 128).addImm(0);
return finishConvertToThreeAddress(MI, MIB, LV);
}
}
return nullptr;
}
MachineInstr *SystemZInstrInfo::foldMemoryOperandImpl(MachineFunction &MF,
MachineInstr *MI,
ArrayRef<unsigned> Ops,
int FrameIndex) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
unsigned Size = MFI->getObjectSize(FrameIndex);
unsigned Opcode = MI->getOpcode();
if (Ops.size() == 2 && Ops[0] == 0 && Ops[1] == 1) {
if ((Opcode == SystemZ::LA || Opcode == SystemZ::LAY) &&
isInt<8>(MI->getOperand(2).getImm()) &&
!MI->getOperand(3).getReg()) {
// LA(Y) %reg, CONST(%reg) -> AGSI %mem, CONST
return BuildMI(MF, MI->getDebugLoc(), get(SystemZ::AGSI))
.addFrameIndex(FrameIndex).addImm(0)
.addImm(MI->getOperand(2).getImm());
}
return nullptr;
}
// All other cases require a single operand.
if (Ops.size() != 1)
return nullptr;
unsigned OpNum = Ops[0];
assert(Size == MF.getRegInfo()
.getRegClass(MI->getOperand(OpNum).getReg())->getSize() &&
"Invalid size combination");
if ((Opcode == SystemZ::AHI || Opcode == SystemZ::AGHI) &&
OpNum == 0 &&
isInt<8>(MI->getOperand(2).getImm())) {
// A(G)HI %reg, CONST -> A(G)SI %mem, CONST
Opcode = (Opcode == SystemZ::AHI ? SystemZ::ASI : SystemZ::AGSI);
return BuildMI(MF, MI->getDebugLoc(), get(Opcode))
.addFrameIndex(FrameIndex).addImm(0)
.addImm(MI->getOperand(2).getImm());
}
if (Opcode == SystemZ::LGDR || Opcode == SystemZ::LDGR) {
bool Op0IsGPR = (Opcode == SystemZ::LGDR);
bool Op1IsGPR = (Opcode == SystemZ::LDGR);
// If we're spilling the destination of an LDGR or LGDR, store the
// source register instead.
if (OpNum == 0) {
unsigned StoreOpcode = Op1IsGPR ? SystemZ::STG : SystemZ::STD;
return BuildMI(MF, MI->getDebugLoc(), get(StoreOpcode))
.addOperand(MI->getOperand(1)).addFrameIndex(FrameIndex)
.addImm(0).addReg(0);
}
// If we're spilling the source of an LDGR or LGDR, load the
// destination register instead.
if (OpNum == 1) {
unsigned LoadOpcode = Op0IsGPR ? SystemZ::LG : SystemZ::LD;
unsigned Dest = MI->getOperand(0).getReg();
return BuildMI(MF, MI->getDebugLoc(), get(LoadOpcode), Dest)
.addFrameIndex(FrameIndex).addImm(0).addReg(0);
}
}
// Look for cases where the source of a simple store or the destination
// of a simple load is being spilled. Try to use MVC instead.
//
// Although MVC is in practice a fast choice in these cases, it is still
// logically a bytewise copy. This means that we cannot use it if the
// load or store is volatile. We also wouldn't be able to use MVC if
// the two memories partially overlap, but that case cannot occur here,
// because we know that one of the memories is a full frame index.
//
// For performance reasons, we also want to avoid using MVC if the addresses
// might be equal. We don't worry about that case here, because spill slot
// coloring happens later, and because we have special code to remove
// MVCs that turn out to be redundant.
if (OpNum == 0 && MI->hasOneMemOperand()) {
MachineMemOperand *MMO = *MI->memoperands_begin();
if (MMO->getSize() == Size && !MMO->isVolatile()) {
// Handle conversion of loads.
if (isSimpleBD12Move(MI, SystemZII::SimpleBDXLoad)) {
return BuildMI(MF, MI->getDebugLoc(), get(SystemZ::MVC))
.addFrameIndex(FrameIndex).addImm(0).addImm(Size)
.addOperand(MI->getOperand(1)).addImm(MI->getOperand(2).getImm())
.addMemOperand(MMO);
}
// Handle conversion of stores.
if (isSimpleBD12Move(MI, SystemZII::SimpleBDXStore)) {
return BuildMI(MF, MI->getDebugLoc(), get(SystemZ::MVC))
.addOperand(MI->getOperand(1)).addImm(MI->getOperand(2).getImm())
.addImm(Size).addFrameIndex(FrameIndex).addImm(0)
.addMemOperand(MMO);
}
}
}
// If the spilled operand is the final one, try to change <INSN>R
// into <INSN>.
int MemOpcode = SystemZ::getMemOpcode(Opcode);
if (MemOpcode >= 0) {
unsigned NumOps = MI->getNumExplicitOperands();
if (OpNum == NumOps - 1) {
const MCInstrDesc &MemDesc = get(MemOpcode);
uint64_t AccessBytes = SystemZII::getAccessSize(MemDesc.TSFlags);
assert(AccessBytes != 0 && "Size of access should be known");
assert(AccessBytes <= Size && "Access outside the frame index");
uint64_t Offset = Size - AccessBytes;
MachineInstrBuilder MIB = BuildMI(MF, MI->getDebugLoc(), get(MemOpcode));
for (unsigned I = 0; I < OpNum; ++I)
MIB.addOperand(MI->getOperand(I));
MIB.addFrameIndex(FrameIndex).addImm(Offset);
if (MemDesc.TSFlags & SystemZII::HasIndex)
MIB.addReg(0);
return MIB;
}
}
return nullptr;
}
MachineInstr *
SystemZInstrInfo::foldMemoryOperandImpl(MachineFunction &MF, MachineInstr *MI,
ArrayRef<unsigned> Ops,
MachineInstr *LoadMI) const {
return nullptr;
}
bool
SystemZInstrInfo::expandPostRAPseudo(MachineBasicBlock::iterator MI) const {
switch (MI->getOpcode()) {
case SystemZ::L128:
splitMove(MI, SystemZ::LG);
return true;
case SystemZ::ST128:
splitMove(MI, SystemZ::STG);
return true;
case SystemZ::LX:
splitMove(MI, SystemZ::LD);
return true;
case SystemZ::STX:
splitMove(MI, SystemZ::STD);
return true;
case SystemZ::LBMux:
expandRXYPseudo(MI, SystemZ::LB, SystemZ::LBH);
return true;
case SystemZ::LHMux:
expandRXYPseudo(MI, SystemZ::LH, SystemZ::LHH);
return true;
case SystemZ::LLCRMux:
expandZExtPseudo(MI, SystemZ::LLCR, 8);
return true;
case SystemZ::LLHRMux:
expandZExtPseudo(MI, SystemZ::LLHR, 16);
return true;
case SystemZ::LLCMux:
expandRXYPseudo(MI, SystemZ::LLC, SystemZ::LLCH);
return true;
case SystemZ::LLHMux:
expandRXYPseudo(MI, SystemZ::LLH, SystemZ::LLHH);
return true;
case SystemZ::LMux:
expandRXYPseudo(MI, SystemZ::L, SystemZ::LFH);
return true;
case SystemZ::STCMux:
expandRXYPseudo(MI, SystemZ::STC, SystemZ::STCH);
return true;
case SystemZ::STHMux:
expandRXYPseudo(MI, SystemZ::STH, SystemZ::STHH);
return true;
case SystemZ::STMux:
expandRXYPseudo(MI, SystemZ::ST, SystemZ::STFH);
return true;
case SystemZ::LHIMux:
expandRIPseudo(MI, SystemZ::LHI, SystemZ::IIHF, true);
return true;
case SystemZ::IIFMux:
expandRIPseudo(MI, SystemZ::IILF, SystemZ::IIHF, false);
return true;
case SystemZ::IILMux:
expandRIPseudo(MI, SystemZ::IILL, SystemZ::IIHL, false);
return true;
case SystemZ::IIHMux:
expandRIPseudo(MI, SystemZ::IILH, SystemZ::IIHH, false);
return true;
case SystemZ::NIFMux:
expandRIPseudo(MI, SystemZ::NILF, SystemZ::NIHF, false);
return true;
case SystemZ::NILMux:
expandRIPseudo(MI, SystemZ::NILL, SystemZ::NIHL, false);
return true;
case SystemZ::NIHMux:
expandRIPseudo(MI, SystemZ::NILH, SystemZ::NIHH, false);
return true;
case SystemZ::OIFMux:
expandRIPseudo(MI, SystemZ::OILF, SystemZ::OIHF, false);
return true;
case SystemZ::OILMux:
expandRIPseudo(MI, SystemZ::OILL, SystemZ::OIHL, false);
return true;
case SystemZ::OIHMux:
expandRIPseudo(MI, SystemZ::OILH, SystemZ::OIHH, false);
return true;
case SystemZ::XIFMux:
expandRIPseudo(MI, SystemZ::XILF, SystemZ::XIHF, false);
return true;
case SystemZ::TMLMux:
expandRIPseudo(MI, SystemZ::TMLL, SystemZ::TMHL, false);
return true;
case SystemZ::TMHMux:
expandRIPseudo(MI, SystemZ::TMLH, SystemZ::TMHH, false);
return true;
case SystemZ::AHIMux:
expandRIPseudo(MI, SystemZ::AHI, SystemZ::AIH, false);
return true;
case SystemZ::AHIMuxK:
expandRIEPseudo(MI, SystemZ::AHI, SystemZ::AHIK, SystemZ::AIH);
return true;
case SystemZ::AFIMux:
expandRIPseudo(MI, SystemZ::AFI, SystemZ::AIH, false);
return true;
case SystemZ::CFIMux:
expandRIPseudo(MI, SystemZ::CFI, SystemZ::CIH, false);
return true;
case SystemZ::CLFIMux:
expandRIPseudo(MI, SystemZ::CLFI, SystemZ::CLIH, false);
return true;
case SystemZ::CMux:
expandRXYPseudo(MI, SystemZ::C, SystemZ::CHF);
return true;
case SystemZ::CLMux:
expandRXYPseudo(MI, SystemZ::CL, SystemZ::CLHF);
return true;
case SystemZ::RISBMux: {
bool DestIsHigh = isHighReg(MI->getOperand(0).getReg());
bool SrcIsHigh = isHighReg(MI->getOperand(2).getReg());
if (SrcIsHigh == DestIsHigh)
MI->setDesc(get(DestIsHigh ? SystemZ::RISBHH : SystemZ::RISBLL));
else {
MI->setDesc(get(DestIsHigh ? SystemZ::RISBHL : SystemZ::RISBLH));
MI->getOperand(5).setImm(MI->getOperand(5).getImm() ^ 32);
}
return true;
}
case SystemZ::ADJDYNALLOC:
splitAdjDynAlloc(MI);
return true;
default:
return false;
}
}
uint64_t SystemZInstrInfo::getInstSizeInBytes(const MachineInstr *MI) const {
if (MI->getOpcode() == TargetOpcode::INLINEASM) {
const MachineFunction *MF = MI->getParent()->getParent();
const char *AsmStr = MI->getOperand(0).getSymbolName();
return getInlineAsmLength(AsmStr, *MF->getTarget().getMCAsmInfo());
}
return MI->getDesc().getSize();
}
SystemZII::Branch
SystemZInstrInfo::getBranchInfo(const MachineInstr *MI) const {
switch (MI->getOpcode()) {
case SystemZ::BR:
case SystemZ::J:
case SystemZ::JG:
return SystemZII::Branch(SystemZII::BranchNormal, SystemZ::CCMASK_ANY,
SystemZ::CCMASK_ANY, &MI->getOperand(0));
case SystemZ::BRC:
case SystemZ::BRCL:
return SystemZII::Branch(SystemZII::BranchNormal,
MI->getOperand(0).getImm(),
MI->getOperand(1).getImm(), &MI->getOperand(2));
case SystemZ::BRCT:
return SystemZII::Branch(SystemZII::BranchCT, SystemZ::CCMASK_ICMP,
SystemZ::CCMASK_CMP_NE, &MI->getOperand(2));
case SystemZ::BRCTG:
return SystemZII::Branch(SystemZII::BranchCTG, SystemZ::CCMASK_ICMP,
SystemZ::CCMASK_CMP_NE, &MI->getOperand(2));
case SystemZ::CIJ:
case SystemZ::CRJ:
return SystemZII::Branch(SystemZII::BranchC, SystemZ::CCMASK_ICMP,
MI->getOperand(2).getImm(), &MI->getOperand(3));
case SystemZ::CLIJ:
case SystemZ::CLRJ:
return SystemZII::Branch(SystemZII::BranchCL, SystemZ::CCMASK_ICMP,
MI->getOperand(2).getImm(), &MI->getOperand(3));
case SystemZ::CGIJ:
case SystemZ::CGRJ:
return SystemZII::Branch(SystemZII::BranchCG, SystemZ::CCMASK_ICMP,
MI->getOperand(2).getImm(), &MI->getOperand(3));
case SystemZ::CLGIJ:
case SystemZ::CLGRJ:
return SystemZII::Branch(SystemZII::BranchCLG, SystemZ::CCMASK_ICMP,
MI->getOperand(2).getImm(), &MI->getOperand(3));
default:
llvm_unreachable("Unrecognized branch opcode");
}
}
void SystemZInstrInfo::getLoadStoreOpcodes(const TargetRegisterClass *RC,
unsigned &LoadOpcode,
unsigned &StoreOpcode) const {
if (RC == &SystemZ::GR32BitRegClass || RC == &SystemZ::ADDR32BitRegClass) {
LoadOpcode = SystemZ::L;
StoreOpcode = SystemZ::ST;
} else if (RC == &SystemZ::GRH32BitRegClass) {
LoadOpcode = SystemZ::LFH;
StoreOpcode = SystemZ::STFH;
} else if (RC == &SystemZ::GRX32BitRegClass) {
LoadOpcode = SystemZ::LMux;
StoreOpcode = SystemZ::STMux;
} else if (RC == &SystemZ::GR64BitRegClass ||
RC == &SystemZ::ADDR64BitRegClass) {
LoadOpcode = SystemZ::LG;
StoreOpcode = SystemZ::STG;
} else if (RC == &SystemZ::GR128BitRegClass ||
RC == &SystemZ::ADDR128BitRegClass) {
LoadOpcode = SystemZ::L128;
StoreOpcode = SystemZ::ST128;
} else if (RC == &SystemZ::FP32BitRegClass) {
LoadOpcode = SystemZ::LE;
StoreOpcode = SystemZ::STE;
} else if (RC == &SystemZ::FP64BitRegClass) {
LoadOpcode = SystemZ::LD;
StoreOpcode = SystemZ::STD;
} else if (RC == &SystemZ::FP128BitRegClass) {
LoadOpcode = SystemZ::LX;
StoreOpcode = SystemZ::STX;
} else
llvm_unreachable("Unsupported regclass to load or store");
}
unsigned SystemZInstrInfo::getOpcodeForOffset(unsigned Opcode,
int64_t Offset) const {
const MCInstrDesc &MCID = get(Opcode);
int64_t Offset2 = (MCID.TSFlags & SystemZII::Is128Bit ? Offset + 8 : Offset);
if (isUInt<12>(Offset) && isUInt<12>(Offset2)) {
// Get the instruction to use for unsigned 12-bit displacements.
int Disp12Opcode = SystemZ::getDisp12Opcode(Opcode);
if (Disp12Opcode >= 0)
return Disp12Opcode;
// All address-related instructions can use unsigned 12-bit
// displacements.
return Opcode;
}
if (isInt<20>(Offset) && isInt<20>(Offset2)) {
// Get the instruction to use for signed 20-bit displacements.
int Disp20Opcode = SystemZ::getDisp20Opcode(Opcode);
if (Disp20Opcode >= 0)
return Disp20Opcode;
// Check whether Opcode allows signed 20-bit displacements.
if (MCID.TSFlags & SystemZII::Has20BitOffset)
return Opcode;
}
return 0;
}
unsigned SystemZInstrInfo::getLoadAndTest(unsigned Opcode) const {
switch (Opcode) {
case SystemZ::L: return SystemZ::LT;
case SystemZ::LY: return SystemZ::LT;
case SystemZ::LG: return SystemZ::LTG;
case SystemZ::LGF: return SystemZ::LTGF;
case SystemZ::LR: return SystemZ::LTR;
case SystemZ::LGFR: return SystemZ::LTGFR;
case SystemZ::LGR: return SystemZ::LTGR;
case SystemZ::LER: return SystemZ::LTEBR;
case SystemZ::LDR: return SystemZ::LTDBR;
case SystemZ::LXR: return SystemZ::LTXBR;
// On zEC12 we prefer to use RISBGN. But if there is a chance to
// actually use the condition code, we may turn it back into RISGB.
// Note that RISBG is not really a "load-and-test" instruction,
// but sets the same condition code values, so is OK to use here.
case SystemZ::RISBGN: return SystemZ::RISBG;
default: return 0;
}
}
// Return true if Mask matches the regexp 0*1+0*, given that zero masks
// have already been filtered out. Store the first set bit in LSB and
// the number of set bits in Length if so.
static bool isStringOfOnes(uint64_t Mask, unsigned &LSB, unsigned &Length) {
unsigned First = findFirstSet(Mask);
uint64_t Top = (Mask >> First) + 1;
if ((Top & -Top) == Top) {
LSB = First;
Length = findFirstSet(Top);
return true;
}
return false;
}
bool SystemZInstrInfo::isRxSBGMask(uint64_t Mask, unsigned BitSize,
unsigned &Start, unsigned &End) const {
// Reject trivial all-zero masks.
if (Mask == 0)
return false;
// Handle the 1+0+ or 0+1+0* cases. Start then specifies the index of
// the msb and End specifies the index of the lsb.
unsigned LSB, Length;
if (isStringOfOnes(Mask, LSB, Length)) {
Start = 63 - (LSB + Length - 1);
End = 63 - LSB;
return true;
}
// Handle the wrap-around 1+0+1+ cases. Start then specifies the msb
// of the low 1s and End specifies the lsb of the high 1s.
if (isStringOfOnes(Mask ^ allOnes(BitSize), LSB, Length)) {
assert(LSB > 0 && "Bottom bit must be set");
assert(LSB + Length < BitSize && "Top bit must be set");
Start = 63 - (LSB - 1);
End = 63 - (LSB + Length);
return true;
}
return false;
}
unsigned SystemZInstrInfo::getCompareAndBranch(unsigned Opcode,
const MachineInstr *MI) const {
switch (Opcode) {
case SystemZ::CR:
return SystemZ::CRJ;
case SystemZ::CGR:
return SystemZ::CGRJ;
case SystemZ::CHI:
return MI && isInt<8>(MI->getOperand(1).getImm()) ? SystemZ::CIJ : 0;
case SystemZ::CGHI:
return MI && isInt<8>(MI->getOperand(1).getImm()) ? SystemZ::CGIJ : 0;
case SystemZ::CLR:
return SystemZ::CLRJ;
case SystemZ::CLGR:
return SystemZ::CLGRJ;
case SystemZ::CLFI:
return MI && isUInt<8>(MI->getOperand(1).getImm()) ? SystemZ::CLIJ : 0;
case SystemZ::CLGFI:
return MI && isUInt<8>(MI->getOperand(1).getImm()) ? SystemZ::CLGIJ : 0;
default:
return 0;
}
}
void SystemZInstrInfo::loadImmediate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned Reg, uint64_t Value) const {
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
unsigned Opcode;
if (isInt<16>(Value))
Opcode = SystemZ::LGHI;
else if (SystemZ::isImmLL(Value))
Opcode = SystemZ::LLILL;
else if (SystemZ::isImmLH(Value)) {
Opcode = SystemZ::LLILH;
Value >>= 16;
} else {
assert(isInt<32>(Value) && "Huge values not handled yet");
Opcode = SystemZ::LGFI;
}
BuildMI(MBB, MBBI, DL, get(Opcode), Reg).addImm(Value);
}