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llvm-6502/lib/Target/ARM64/ARM64InstrInfo.cpp
Tim Northover 7b837d8c75 ARM64: initial backend import 
This adds a second implementation of the AArch64 architecture to LLVM,
accessible in parallel via the "arm64" triple. The plan over the
coming weeks & months is to merge the two into a single backend,
during which time thorough code review should naturally occur.

Everything will be easier with the target in-tree though, hence this
commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205090 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-29 10:18:08 +00:00

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//===- ARM64InstrInfo.cpp - ARM64 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 ARM64 implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "ARM64InstrInfo.h"
#include "ARM64Subtarget.h"
#include "MCTargetDesc/ARM64AddressingModes.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
#include "llvm/MC/MCInst.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
#define GET_INSTRINFO_CTOR_DTOR
#include "ARM64GenInstrInfo.inc"
using namespace llvm;
ARM64InstrInfo::ARM64InstrInfo(const ARM64Subtarget &STI)
: ARM64GenInstrInfo(ARM64::ADJCALLSTACKDOWN, ARM64::ADJCALLSTACKUP),
RI(this, &STI), Subtarget(STI) {}
/// GetInstSize - Return the number of bytes of code the specified
/// instruction may be. This returns the maximum number of bytes.
unsigned ARM64InstrInfo::GetInstSizeInBytes(const MachineInstr *MI) const {
const MCInstrDesc &Desc = MI->getDesc();
switch (Desc.getOpcode()) {
default:
// Anything not explicitly designated otherwise is a nomal 4-byte insn.
return 4;
case TargetOpcode::DBG_VALUE:
case TargetOpcode::EH_LABEL:
case TargetOpcode::IMPLICIT_DEF:
case TargetOpcode::KILL:
return 0;
}
llvm_unreachable("GetInstSizeInBytes()- Unable to determin insn size");
}
static void parseCondBranch(MachineInstr *LastInst, MachineBasicBlock *&Target,
SmallVectorImpl<MachineOperand> &Cond) {
// Block ends with fall-through condbranch.
switch (LastInst->getOpcode()) {
default:
llvm_unreachable("Unknown branch instruction?");
case ARM64::Bcc:
Target = LastInst->getOperand(1).getMBB();
Cond.push_back(LastInst->getOperand(0));
break;
case ARM64::CBZW:
case ARM64::CBZX:
case ARM64::CBNZW:
case ARM64::CBNZX:
Target = LastInst->getOperand(1).getMBB();
Cond.push_back(MachineOperand::CreateImm(-1));
Cond.push_back(MachineOperand::CreateImm(LastInst->getOpcode()));
Cond.push_back(LastInst->getOperand(0));
break;
case ARM64::TBZ:
case ARM64::TBNZ:
Target = LastInst->getOperand(2).getMBB();
Cond.push_back(MachineOperand::CreateImm(-1));
Cond.push_back(MachineOperand::CreateImm(LastInst->getOpcode()));
Cond.push_back(LastInst->getOperand(0));
Cond.push_back(LastInst->getOperand(1));
}
}
// Branch analysis.
bool ARM64InstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,
MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify) const {
// If the block has no terminators, it just falls into the block after it.
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin())
return false;
--I;
while (I->isDebugValue()) {
if (I == MBB.begin())
return false;
--I;
}
if (!isUnpredicatedTerminator(I))
return false;
// Get the last instruction in the block.
MachineInstr *LastInst = I;
// If there is only one terminator instruction, process it.
unsigned LastOpc = LastInst->getOpcode();
if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
if (isUncondBranchOpcode(LastOpc)) {
TBB = LastInst->getOperand(0).getMBB();
return false;
}
if (isCondBranchOpcode(LastOpc)) {
// Block ends with fall-through condbranch.
parseCondBranch(LastInst, TBB, Cond);
return false;
}
return true; // Can't handle indirect branch.
}
// Get the instruction before it if it is a terminator.
MachineInstr *SecondLastInst = I;
unsigned SecondLastOpc = SecondLastInst->getOpcode();
// If AllowModify is true and the block ends with two or more unconditional
// branches, delete all but the first unconditional branch.
if (AllowModify && isUncondBranchOpcode(LastOpc)) {
while (isUncondBranchOpcode(SecondLastOpc)) {
LastInst->eraseFromParent();
LastInst = SecondLastInst;
LastOpc = LastInst->getOpcode();
if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
// Return now the only terminator is an unconditional branch.
TBB = LastInst->getOperand(0).getMBB();
return false;
} else {
SecondLastInst = I;
SecondLastOpc = SecondLastInst->getOpcode();
}
}
}
// If there are three terminators, we don't know what sort of block this is.
if (SecondLastInst && I != MBB.begin() && isUnpredicatedTerminator(--I))
return true;
// If the block ends with a B and a Bcc, handle it.
if (isCondBranchOpcode(SecondLastOpc) && isUncondBranchOpcode(LastOpc)) {
parseCondBranch(SecondLastInst, TBB, Cond);
FBB = LastInst->getOperand(0).getMBB();
return false;
}
// If the block ends with two unconditional branches, handle it. The second
// one is not executed, so remove it.
if (isUncondBranchOpcode(SecondLastOpc) && isUncondBranchOpcode(LastOpc)) {
TBB = SecondLastInst->getOperand(0).getMBB();
I = LastInst;
if (AllowModify)
I->eraseFromParent();
return false;
}
// ...likewise if it ends with an indirect branch followed by an unconditional
// branch.
if (isIndirectBranchOpcode(SecondLastOpc) && isUncondBranchOpcode(LastOpc)) {
I = LastInst;
if (AllowModify)
I->eraseFromParent();
return true;
}
// Otherwise, can't handle this.
return true;
}
bool ARM64InstrInfo::ReverseBranchCondition(
SmallVectorImpl<MachineOperand> &Cond) const {
if (Cond[0].getImm() != -1) {
// Regular Bcc
ARM64CC::CondCode CC = (ARM64CC::CondCode)(int)Cond[0].getImm();
Cond[0].setImm(ARM64CC::getInvertedCondCode(CC));
} else {
// Folded compare-and-branch
switch (Cond[1].getImm()) {
default:
llvm_unreachable("Unknown conditional branch!");
case ARM64::CBZW:
Cond[1].setImm(ARM64::CBNZW);
break;
case ARM64::CBNZW:
Cond[1].setImm(ARM64::CBZW);
break;
case ARM64::CBZX:
Cond[1].setImm(ARM64::CBNZX);
break;
case ARM64::CBNZX:
Cond[1].setImm(ARM64::CBZX);
break;
case ARM64::TBZ:
Cond[1].setImm(ARM64::TBNZ);
break;
case ARM64::TBNZ:
Cond[1].setImm(ARM64::TBZ);
break;
}
}
return false;
}
unsigned ARM64InstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin())
return 0;
--I;
while (I->isDebugValue()) {
if (I == MBB.begin())
return 0;
--I;
}
if (!isUncondBranchOpcode(I->getOpcode()) &&
!isCondBranchOpcode(I->getOpcode()))
return 0;
// Remove the branch.
I->eraseFromParent();
I = MBB.end();
if (I == MBB.begin())
return 1;
--I;
if (!isCondBranchOpcode(I->getOpcode()))
return 1;
// Remove the branch.
I->eraseFromParent();
return 2;
}
void ARM64InstrInfo::instantiateCondBranch(
MachineBasicBlock &MBB, DebugLoc DL, MachineBasicBlock *TBB,
const SmallVectorImpl<MachineOperand> &Cond) const {
if (Cond[0].getImm() != -1) {
// Regular Bcc
BuildMI(&MBB, DL, get(ARM64::Bcc)).addImm(Cond[0].getImm()).addMBB(TBB);
} else {
// Folded compare-and-branch
const MachineInstrBuilder MIB =
BuildMI(&MBB, DL, get(Cond[1].getImm())).addReg(Cond[2].getReg());
if (Cond.size() > 3)
MIB.addImm(Cond[3].getImm());
MIB.addMBB(TBB);
}
}
unsigned ARM64InstrInfo::InsertBranch(
MachineBasicBlock &MBB, MachineBasicBlock *TBB, MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond, DebugLoc DL) const {
// Shouldn't be a fall through.
assert(TBB && "InsertBranch must not be told to insert a fallthrough");
if (FBB == 0) {
if (Cond.empty()) // Unconditional branch?
BuildMI(&MBB, DL, get(ARM64::B)).addMBB(TBB);
else
instantiateCondBranch(MBB, DL, TBB, Cond);
return 1;
}
// Two-way conditional branch.
instantiateCondBranch(MBB, DL, TBB, Cond);
BuildMI(&MBB, DL, get(ARM64::B)).addMBB(FBB);
return 2;
}
// Find the original register that VReg is copied from.
static unsigned removeCopies(const MachineRegisterInfo &MRI, unsigned VReg) {
while (TargetRegisterInfo::isVirtualRegister(VReg)) {
const MachineInstr *DefMI = MRI.getVRegDef(VReg);
if (!DefMI->isFullCopy())
return VReg;
VReg = DefMI->getOperand(1).getReg();
}
return VReg;
}
// Determine if VReg is defined by an instruction that can be folded into a
// csel instruction. If so, return the folded opcode, and the replacement
// register.
static unsigned canFoldIntoCSel(const MachineRegisterInfo &MRI, unsigned VReg,
unsigned *NewVReg = 0) {
VReg = removeCopies(MRI, VReg);
if (!TargetRegisterInfo::isVirtualRegister(VReg))
return 0;
bool Is64Bit = ARM64::GPR64allRegClass.hasSubClassEq(MRI.getRegClass(VReg));
const MachineInstr *DefMI = MRI.getVRegDef(VReg);
unsigned Opc = 0;
unsigned SrcOpNum = 0;
switch (DefMI->getOpcode()) {
case ARM64::ADDSXri:
case ARM64::ADDSWri:
// if CPSR is used, do not fold.
if (DefMI->findRegisterDefOperandIdx(ARM64::CPSR, true) == -1)
return 0;
// fall-through to ADDXri and ADDWri.
case ARM64::ADDXri:
case ARM64::ADDWri:
// add x, 1 -> csinc.
if (!DefMI->getOperand(2).isImm() || DefMI->getOperand(2).getImm() != 1 ||
DefMI->getOperand(3).getImm() != 0)
return 0;
SrcOpNum = 1;
Opc = Is64Bit ? ARM64::CSINCXr : ARM64::CSINCWr;
break;
case ARM64::ORNXrr:
case ARM64::ORNWrr: {
// not x -> csinv, represented as orn dst, xzr, src.
unsigned ZReg = removeCopies(MRI, DefMI->getOperand(1).getReg());
if (ZReg != ARM64::XZR && ZReg != ARM64::WZR)
return 0;
SrcOpNum = 2;
Opc = Is64Bit ? ARM64::CSINVXr : ARM64::CSINVWr;
break;
}
case ARM64::SUBSXrr:
case ARM64::SUBSWrr:
// if CPSR is used, do not fold.
if (DefMI->findRegisterDefOperandIdx(ARM64::CPSR, true) == -1)
return 0;
// fall-through to SUBXrr and SUBWrr.
case ARM64::SUBXrr:
case ARM64::SUBWrr: {
// neg x -> csneg, represented as sub dst, xzr, src.
unsigned ZReg = removeCopies(MRI, DefMI->getOperand(1).getReg());
if (ZReg != ARM64::XZR && ZReg != ARM64::WZR)
return 0;
SrcOpNum = 2;
Opc = Is64Bit ? ARM64::CSNEGXr : ARM64::CSNEGWr;
break;
}
default:
return 0;
}
assert(Opc && SrcOpNum && "Missing parameters");
if (NewVReg)
*NewVReg = DefMI->getOperand(SrcOpNum).getReg();
return Opc;
}
bool ARM64InstrInfo::canInsertSelect(
const MachineBasicBlock &MBB, const SmallVectorImpl<MachineOperand> &Cond,
unsigned TrueReg, unsigned FalseReg, int &CondCycles, int &TrueCycles,
int &FalseCycles) const {
// Check register classes.
const MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
const TargetRegisterClass *RC =
RI.getCommonSubClass(MRI.getRegClass(TrueReg), MRI.getRegClass(FalseReg));
if (!RC)
return false;
// Expanding cbz/tbz requires an extra cycle of latency on the condition.
unsigned ExtraCondLat = Cond.size() != 1;
// GPRs are handled by csel.
// FIXME: Fold in x+1, -x, and ~x when applicable.
if (ARM64::GPR64allRegClass.hasSubClassEq(RC) ||
ARM64::GPR32allRegClass.hasSubClassEq(RC)) {
// Single-cycle csel, csinc, csinv, and csneg.
CondCycles = 1 + ExtraCondLat;
TrueCycles = FalseCycles = 1;
if (canFoldIntoCSel(MRI, TrueReg))
TrueCycles = 0;
else if (canFoldIntoCSel(MRI, FalseReg))
FalseCycles = 0;
return true;
}
// Scalar floating point is handled by fcsel.
// FIXME: Form fabs, fmin, and fmax when applicable.
if (ARM64::FPR64RegClass.hasSubClassEq(RC) ||
ARM64::FPR32RegClass.hasSubClassEq(RC)) {
CondCycles = 5 + ExtraCondLat;
TrueCycles = FalseCycles = 2;
return true;
}
// Can't do vectors.
return false;
}
void ARM64InstrInfo::insertSelect(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I, DebugLoc DL,
unsigned DstReg,
const SmallVectorImpl<MachineOperand> &Cond,
unsigned TrueReg, unsigned FalseReg) const {
MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
// Parse the condition code, see parseCondBranch() above.
ARM64CC::CondCode CC;
switch (Cond.size()) {
default:
llvm_unreachable("Unknown condition opcode in Cond");
case 1: // b.cc
CC = ARM64CC::CondCode(Cond[0].getImm());
break;
case 3: { // cbz/cbnz
// We must insert a compare against 0.
bool Is64Bit;
switch (Cond[1].getImm()) {
default:
llvm_unreachable("Unknown branch opcode in Cond");
case ARM64::CBZW:
Is64Bit = 0;
CC = ARM64CC::EQ;
break;
case ARM64::CBZX:
Is64Bit = 1;
CC = ARM64CC::EQ;
break;
case ARM64::CBNZW:
Is64Bit = 0;
CC = ARM64CC::NE;
break;
case ARM64::CBNZX:
Is64Bit = 1;
CC = ARM64CC::NE;
break;
}
unsigned SrcReg = Cond[2].getReg();
if (Is64Bit) {
// cmp reg, #0 is actually subs xzr, reg, #0.
MRI.constrainRegClass(SrcReg, &ARM64::GPR64spRegClass);
BuildMI(MBB, I, DL, get(ARM64::SUBSXri), ARM64::XZR)
.addReg(SrcReg)
.addImm(0)
.addImm(0);
} else {
MRI.constrainRegClass(SrcReg, &ARM64::GPR32spRegClass);
BuildMI(MBB, I, DL, get(ARM64::SUBSWri), ARM64::WZR)
.addReg(SrcReg)
.addImm(0)
.addImm(0);
}
break;
}
case 4: { // tbz/tbnz
// We must insert a tst instruction.
switch (Cond[1].getImm()) {
default:
llvm_unreachable("Unknown branch opcode in Cond");
case ARM64::TBZ:
CC = ARM64CC::EQ;
break;
case ARM64::TBNZ:
CC = ARM64CC::NE;
break;
}
// cmp reg, #foo is actually ands xzr, reg, #1<<foo.
BuildMI(MBB, I, DL, get(ARM64::ANDSXri), ARM64::XZR)
.addReg(Cond[2].getReg())
.addImm(ARM64_AM::encodeLogicalImmediate(1ull << Cond[3].getImm(), 64));
break;
}
}
unsigned Opc = 0;
const TargetRegisterClass *RC = 0;
bool TryFold = false;
if (MRI.constrainRegClass(DstReg, &ARM64::GPR64RegClass)) {
RC = &ARM64::GPR64RegClass;
Opc = ARM64::CSELXr;
TryFold = true;
} else if (MRI.constrainRegClass(DstReg, &ARM64::GPR32RegClass)) {
RC = &ARM64::GPR32RegClass;
Opc = ARM64::CSELWr;
TryFold = true;
} else if (MRI.constrainRegClass(DstReg, &ARM64::FPR64RegClass)) {
RC = &ARM64::FPR64RegClass;
Opc = ARM64::FCSELDrrr;
} else if (MRI.constrainRegClass(DstReg, &ARM64::FPR32RegClass)) {
RC = &ARM64::FPR32RegClass;
Opc = ARM64::FCSELSrrr;
}
assert(RC && "Unsupported regclass");
// Try folding simple instructions into the csel.
if (TryFold) {
unsigned NewVReg = 0;
unsigned FoldedOpc = canFoldIntoCSel(MRI, TrueReg, &NewVReg);
if (FoldedOpc) {
// The folded opcodes csinc, csinc and csneg apply the operation to
// FalseReg, so we need to invert the condition.
CC = ARM64CC::getInvertedCondCode(CC);
TrueReg = FalseReg;
} else
FoldedOpc = canFoldIntoCSel(MRI, FalseReg, &NewVReg);
// Fold the operation. Leave any dead instructions for DCE to clean up.
if (FoldedOpc) {
FalseReg = NewVReg;
Opc = FoldedOpc;
// The extends the live range of NewVReg.
MRI.clearKillFlags(NewVReg);
}
}
// Pull all virtual register into the appropriate class.
MRI.constrainRegClass(TrueReg, RC);
MRI.constrainRegClass(FalseReg, RC);
// Insert the csel.
BuildMI(MBB, I, DL, get(Opc), DstReg).addReg(TrueReg).addReg(FalseReg).addImm(
CC);
}
bool ARM64InstrInfo::isCoalescableExtInstr(const MachineInstr &MI,
unsigned &SrcReg, unsigned &DstReg,
unsigned &SubIdx) const {
switch (MI.getOpcode()) {
default:
return false;
case ARM64::SBFMXri: // aka sxtw
case ARM64::UBFMXri: // aka uxtw
// Check for the 32 -> 64 bit extension case, these instructions can do
// much more.
if (MI.getOperand(2).getImm() != 0 || MI.getOperand(3).getImm() != 31)
return false;
// This is a signed or unsigned 32 -> 64 bit extension.
SrcReg = MI.getOperand(1).getReg();
DstReg = MI.getOperand(0).getReg();
SubIdx = ARM64::sub_32;
return true;
}
}
/// analyzeCompare - For a comparison instruction, return the source registers
/// in SrcReg and SrcReg2, and the value it compares against in CmpValue.
/// Return true if the comparison instruction can be analyzed.
bool ARM64InstrInfo::analyzeCompare(const MachineInstr *MI, unsigned &SrcReg,
unsigned &SrcReg2, int &CmpMask,
int &CmpValue) const {
switch (MI->getOpcode()) {
default:
break;
case ARM64::SUBSWrr:
case ARM64::SUBSWrs:
case ARM64::SUBSWrx:
case ARM64::SUBSXrr:
case ARM64::SUBSXrs:
case ARM64::SUBSXrx:
case ARM64::ADDSWrr:
case ARM64::ADDSWrs:
case ARM64::ADDSWrx:
case ARM64::ADDSXrr:
case ARM64::ADDSXrs:
case ARM64::ADDSXrx:
// Replace SUBSWrr with SUBWrr if CPSR is not used.
SrcReg = MI->getOperand(1).getReg();
SrcReg2 = MI->getOperand(2).getReg();
CmpMask = ~0;
CmpValue = 0;
return true;
case ARM64::SUBSWri:
case ARM64::ADDSWri:
case ARM64::ANDSWri:
case ARM64::SUBSXri:
case ARM64::ADDSXri:
case ARM64::ANDSXri:
SrcReg = MI->getOperand(1).getReg();
SrcReg2 = 0;
CmpMask = ~0;
CmpValue = MI->getOperand(2).getImm();
return true;
}
return false;
}
static bool UpdateOperandRegClass(MachineInstr *Instr) {
MachineBasicBlock *MBB = Instr->getParent();
assert(MBB && "Can't get MachineBasicBlock here");
MachineFunction *MF = MBB->getParent();
assert(MF && "Can't get MachineFunction here");
const TargetMachine *TM = &MF->getTarget();
const TargetInstrInfo *TII = TM->getInstrInfo();
const TargetRegisterInfo *TRI = TM->getRegisterInfo();
MachineRegisterInfo *MRI = &MF->getRegInfo();
for (unsigned OpIdx = 0, EndIdx = Instr->getNumOperands(); OpIdx < EndIdx;
++OpIdx) {
MachineOperand &MO = Instr->getOperand(OpIdx);
const TargetRegisterClass *OpRegCstraints =
Instr->getRegClassConstraint(OpIdx, TII, TRI);
// If there's no constraint, there's nothing to do.
if (!OpRegCstraints)
continue;
// If the operand is a frame index, there's nothing to do here.
// A frame index operand will resolve correctly during PEI.
if (MO.isFI())
continue;
assert(MO.isReg() &&
"Operand has register constraints without being a register!");
unsigned Reg = MO.getReg();
if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
if (!OpRegCstraints->contains(Reg))
return false;
} else if (!OpRegCstraints->hasSubClassEq(MRI->getRegClass(Reg)) &&
!MRI->constrainRegClass(Reg, OpRegCstraints))
return false;
}
return true;
}
/// optimizeCompareInstr - Convert the instruction supplying the argument to the
/// comparison into one that sets the zero bit in the flags register.
bool ARM64InstrInfo::optimizeCompareInstr(
MachineInstr *CmpInstr, unsigned SrcReg, unsigned SrcReg2, int CmpMask,
int CmpValue, const MachineRegisterInfo *MRI) const {
// Replace SUBSWrr with SUBWrr if CPSR is not used.
int Cmp_CPSR = CmpInstr->findRegisterDefOperandIdx(ARM64::CPSR, true);
if (Cmp_CPSR != -1) {
unsigned NewOpc;
switch (CmpInstr->getOpcode()) {
default:
return false;
case ARM64::ADDSWrr: NewOpc = ARM64::ADDWrr; break;
case ARM64::ADDSWri: NewOpc = ARM64::ADDWri; break;
case ARM64::ADDSWrs: NewOpc = ARM64::ADDWrs; break;
case ARM64::ADDSWrx: NewOpc = ARM64::ADDWrx; break;
case ARM64::ADDSXrr: NewOpc = ARM64::ADDXrr; break;
case ARM64::ADDSXri: NewOpc = ARM64::ADDXri; break;
case ARM64::ADDSXrs: NewOpc = ARM64::ADDXrs; break;
case ARM64::ADDSXrx: NewOpc = ARM64::ADDXrx; break;
case ARM64::SUBSWrr: NewOpc = ARM64::SUBWrr; break;
case ARM64::SUBSWri: NewOpc = ARM64::SUBWri; break;
case ARM64::SUBSWrs: NewOpc = ARM64::SUBWrs; break;
case ARM64::SUBSWrx: NewOpc = ARM64::SUBWrx; break;
case ARM64::SUBSXrr: NewOpc = ARM64::SUBXrr; break;
case ARM64::SUBSXri: NewOpc = ARM64::SUBXri; break;
case ARM64::SUBSXrs: NewOpc = ARM64::SUBXrs; break;
case ARM64::SUBSXrx: NewOpc = ARM64::SUBXrx; break;
}
const MCInstrDesc &MCID = get(NewOpc);
CmpInstr->setDesc(MCID);
CmpInstr->RemoveOperand(Cmp_CPSR);
bool succeeded = UpdateOperandRegClass(CmpInstr);
(void)succeeded;
assert(succeeded && "Some operands reg class are incompatible!");
return true;
}
// Continue only if we have a "ri" where immediate is zero.
if (CmpValue != 0 || SrcReg2 != 0)
return false;
// CmpInstr is a Compare instruction if destination register is not used.
if (!MRI->use_nodbg_empty(CmpInstr->getOperand(0).getReg()))
return false;
// Get the unique definition of SrcReg.
MachineInstr *MI = MRI->getUniqueVRegDef(SrcReg);
if (!MI)
return false;
// We iterate backward, starting from the instruction before CmpInstr and
// stop when reaching the definition of the source register or done with the
// basic block, to check whether CPSR is used or modified in between.
MachineBasicBlock::iterator I = CmpInstr, E = MI,
B = CmpInstr->getParent()->begin();
// Early exit if CmpInstr is at the beginning of the BB.
if (I == B)
return false;
// Check whether the definition of SrcReg is in the same basic block as
// Compare. If not, we can't optimize away the Compare.
if (MI->getParent() != CmpInstr->getParent())
return false;
// Check that CPSR isn't set between the comparison instruction and the one we
// want to change.
const TargetRegisterInfo *TRI = &getRegisterInfo();
for (--I; I != E; --I) {
const MachineInstr &Instr = *I;
if (Instr.modifiesRegister(ARM64::CPSR, TRI) ||
Instr.readsRegister(ARM64::CPSR, TRI))
// This instruction modifies or uses CPSR after the one we want to
// change. We can't do this transformation.
return false;
if (I == B)
// The 'and' is below the comparison instruction.
return false;
}
unsigned NewOpc = MI->getOpcode();
switch (MI->getOpcode()) {
default:
return false;
case ARM64::ADDSWrr:
case ARM64::ADDSWri:
case ARM64::ADDSXrr:
case ARM64::ADDSXri:
case ARM64::SUBSWrr:
case ARM64::SUBSWri:
case ARM64::SUBSXrr:
case ARM64::SUBSXri:
break;
case ARM64::ADDWrr: NewOpc = ARM64::ADDSWrr; break;
case ARM64::ADDWri: NewOpc = ARM64::ADDSWri; break;
case ARM64::ADDXrr: NewOpc = ARM64::ADDSXrr; break;
case ARM64::ADDXri: NewOpc = ARM64::ADDSXri; break;
case ARM64::ADCWr: NewOpc = ARM64::ADCSWr; break;
case ARM64::ADCXr: NewOpc = ARM64::ADCSXr; break;
case ARM64::SUBWrr: NewOpc = ARM64::SUBSWrr; break;
case ARM64::SUBWri: NewOpc = ARM64::SUBSWri; break;
case ARM64::SUBXrr: NewOpc = ARM64::SUBSXrr; break;
case ARM64::SUBXri: NewOpc = ARM64::SUBSXri; break;
case ARM64::SBCWr: NewOpc = ARM64::SBCSWr; break;
case ARM64::SBCXr: NewOpc = ARM64::SBCSXr; break;
case ARM64::ANDWri: NewOpc = ARM64::ANDSWri; break;
case ARM64::ANDXri: NewOpc = ARM64::ANDSXri; break;
}
// Scan forward for the use of CPSR.
// When checking against MI: if it's a conditional code requires
// checking of V bit, then this is not safe to do.
// It is safe to remove CmpInstr if CPSR is redefined or killed.
// If we are done with the basic block, we need to check whether CPSR is
// live-out.
bool IsSafe = false;
for (MachineBasicBlock::iterator I = CmpInstr,
E = CmpInstr->getParent()->end();
!IsSafe && ++I != E;) {
const MachineInstr &Instr = *I;
for (unsigned IO = 0, EO = Instr.getNumOperands(); !IsSafe && IO != EO;
++IO) {
const MachineOperand &MO = Instr.getOperand(IO);
if (MO.isRegMask() && MO.clobbersPhysReg(ARM64::CPSR)) {
IsSafe = true;
break;
}
if (!MO.isReg() || MO.getReg() != ARM64::CPSR)
continue;
if (MO.isDef()) {
IsSafe = true;
break;
}
// Decode the condition code.
unsigned Opc = Instr.getOpcode();
ARM64CC::CondCode CC;
switch (Opc) {
default:
return false;
case ARM64::Bcc:
CC = (ARM64CC::CondCode)Instr.getOperand(IO - 2).getImm();
break;
case ARM64::CSINVWr:
case ARM64::CSINVXr:
case ARM64::CSINCWr:
case ARM64::CSINCXr:
case ARM64::CSELWr:
case ARM64::CSELXr:
case ARM64::CSNEGWr:
case ARM64::CSNEGXr:
CC = (ARM64CC::CondCode)Instr.getOperand(IO - 1).getImm();
break;
}
// It is not safe to remove Compare instruction if Overflow(V) is used.
switch (CC) {
default:
// CPSR can be used multiple times, we should continue.
break;
case ARM64CC::VS:
case ARM64CC::VC:
case ARM64CC::GE:
case ARM64CC::LT:
case ARM64CC::GT:
case ARM64CC::LE:
return false;
}
}
}
// If CPSR is not killed nor re-defined, we should check whether it is
// live-out. If it is live-out, do not optimize.
if (!IsSafe) {
MachineBasicBlock *MBB = CmpInstr->getParent();
for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
SE = MBB->succ_end();
SI != SE; ++SI)
if ((*SI)->isLiveIn(ARM64::CPSR))
return false;
}
// Update the instruction to set CPSR.
MI->setDesc(get(NewOpc));
CmpInstr->eraseFromParent();
bool succeeded = UpdateOperandRegClass(MI);
(void)succeeded;
assert(succeeded && "Some operands reg class are incompatible!");
MI->addRegisterDefined(ARM64::CPSR, TRI);
return true;
}
// Return true if this instruction simply sets its single destination register
// to zero. This is equivalent to a register rename of the zero-register.
bool ARM64InstrInfo::isGPRZero(const MachineInstr *MI) const {
switch (MI->getOpcode()) {
default:
break;
case ARM64::MOVZWi:
case ARM64::MOVZXi: // movz Rd, #0 (LSL #0)
if (MI->getOperand(1).isImm() && MI->getOperand(1).getImm() == 0) {
assert(MI->getDesc().getNumOperands() == 3 &&
MI->getOperand(2).getImm() == 0 && "invalid MOVZi operands");
return true;
}
break;
case ARM64::ANDWri: // and Rd, Rzr, #imm
return MI->getOperand(1).getReg() == ARM64::WZR;
case ARM64::ANDXri:
return MI->getOperand(1).getReg() == ARM64::XZR;
case TargetOpcode::COPY:
return MI->getOperand(1).getReg() == ARM64::WZR;
}
return false;
}
// Return true if this instruction simply renames a general register without
// modifying bits.
bool ARM64InstrInfo::isGPRCopy(const MachineInstr *MI) const {
switch (MI->getOpcode()) {
default:
break;
case TargetOpcode::COPY: {
// GPR32 copies will by lowered to ORRXrs
unsigned DstReg = MI->getOperand(0).getReg();
return (ARM64::GPR32RegClass.contains(DstReg) ||
ARM64::GPR64RegClass.contains(DstReg));
}
case ARM64::ORRXrs: // orr Xd, Xzr, Xm (LSL #0)
if (MI->getOperand(1).getReg() == ARM64::XZR) {
assert(MI->getDesc().getNumOperands() == 4 &&
MI->getOperand(3).getImm() == 0 && "invalid ORRrs operands");
return true;
}
case ARM64::ADDXri: // add Xd, Xn, #0 (LSL #0)
if (MI->getOperand(2).getImm() == 0) {
assert(MI->getDesc().getNumOperands() == 4 &&
MI->getOperand(3).getImm() == 0 && "invalid ADDXri operands");
return true;
}
}
return false;
}
// Return true if this instruction simply renames a general register without
// modifying bits.
bool ARM64InstrInfo::isFPRCopy(const MachineInstr *MI) const {
switch (MI->getOpcode()) {
default:
break;
case TargetOpcode::COPY: {
// FPR64 copies will by lowered to ORR.16b
unsigned DstReg = MI->getOperand(0).getReg();
return (ARM64::FPR64RegClass.contains(DstReg) ||
ARM64::FPR128RegClass.contains(DstReg));
}
case ARM64::ORRv16i8:
if (MI->getOperand(1).getReg() == MI->getOperand(2).getReg()) {
assert(MI->getDesc().getNumOperands() == 3 && MI->getOperand(0).isReg() &&
"invalid ORRv16i8 operands");
return true;
}
}
return false;
}
unsigned ARM64InstrInfo::isLoadFromStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
switch (MI->getOpcode()) {
default:
break;
case ARM64::LDRWui:
case ARM64::LDRXui:
case ARM64::LDRBui:
case ARM64::LDRHui:
case ARM64::LDRSui:
case ARM64::LDRDui:
case ARM64::LDRQui:
if (MI->getOperand(0).getSubReg() == 0 && MI->getOperand(1).isFI() &&
MI->getOperand(2).isImm() && MI->getOperand(2).getImm() == 0) {
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
break;
}
return 0;
}
unsigned ARM64InstrInfo::isStoreToStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
switch (MI->getOpcode()) {
default:
break;
case ARM64::STRWui:
case ARM64::STRXui:
case ARM64::STRBui:
case ARM64::STRHui:
case ARM64::STRSui:
case ARM64::STRDui:
case ARM64::STRQui:
if (MI->getOperand(0).getSubReg() == 0 && MI->getOperand(1).isFI() &&
MI->getOperand(2).isImm() && MI->getOperand(2).getImm() == 0) {
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
break;
}
return 0;
}
/// Return true if this is load/store scales or extends its register offset.
/// This refers to scaling a dynamic index as opposed to scaled immediates.
/// MI should be a memory op that allows scaled addressing.
bool ARM64InstrInfo::isScaledAddr(const MachineInstr *MI) const {
switch (MI->getOpcode()) {
default:
break;
case ARM64::LDRBBro:
case ARM64::LDRBro:
case ARM64::LDRDro:
case ARM64::LDRHHro:
case ARM64::LDRHro:
case ARM64::LDRQro:
case ARM64::LDRSBWro:
case ARM64::LDRSBXro:
case ARM64::LDRSHWro:
case ARM64::LDRSHXro:
case ARM64::LDRSWro:
case ARM64::LDRSro:
case ARM64::LDRWro:
case ARM64::LDRXro:
case ARM64::STRBBro:
case ARM64::STRBro:
case ARM64::STRDro:
case ARM64::STRHHro:
case ARM64::STRHro:
case ARM64::STRQro:
case ARM64::STRSro:
case ARM64::STRWro:
case ARM64::STRXro:
unsigned Val = MI->getOperand(3).getImm();
ARM64_AM::ExtendType ExtType = ARM64_AM::getMemExtendType(Val);
return (ExtType != ARM64_AM::UXTX) || ARM64_AM::getMemDoShift(Val);
}
return false;
}
/// Check all MachineMemOperands for a hint to suppress pairing.
bool ARM64InstrInfo::isLdStPairSuppressed(const MachineInstr *MI) const {
assert(MOSuppressPair < (1 << MachineMemOperand::MOTargetNumBits) &&
"Too many target MO flags");
for (MachineInstr::mmo_iterator MM = MI->memoperands_begin(),
E = MI->memoperands_end();
MM != E; ++MM) {
if ((*MM)->getFlags() &
(MOSuppressPair << MachineMemOperand::MOTargetStartBit)) {
return true;
}
}
return false;
}
/// Set a flag on the first MachineMemOperand to suppress pairing.
void ARM64InstrInfo::suppressLdStPair(MachineInstr *MI) const {
if (MI->memoperands_empty())
return;
assert(MOSuppressPair < (1 << MachineMemOperand::MOTargetNumBits) &&
"Too many target MO flags");
(*MI->memoperands_begin())
->setFlags(MOSuppressPair << MachineMemOperand::MOTargetStartBit);
}
bool ARM64InstrInfo::getLdStBaseRegImmOfs(MachineInstr *LdSt, unsigned &BaseReg,
unsigned &Offset,
const TargetRegisterInfo *TRI) const {
switch (LdSt->getOpcode()) {
default:
return false;
case ARM64::STRSui:
case ARM64::STRDui:
case ARM64::STRQui:
case ARM64::STRXui:
case ARM64::STRWui:
case ARM64::LDRSui:
case ARM64::LDRDui:
case ARM64::LDRQui:
case ARM64::LDRXui:
case ARM64::LDRWui:
if (!LdSt->getOperand(1).isReg() || !LdSt->getOperand(2).isImm())
return false;
BaseReg = LdSt->getOperand(1).getReg();
MachineFunction &MF = *LdSt->getParent()->getParent();
unsigned Width = getRegClass(LdSt->getDesc(), 0, TRI, MF)->getSize();
Offset = LdSt->getOperand(2).getImm() * Width;
return true;
};
}
/// Detect opportunities for ldp/stp formation.
///
/// Only called for LdSt for which getLdStBaseRegImmOfs returns true.
bool ARM64InstrInfo::shouldClusterLoads(MachineInstr *FirstLdSt,
MachineInstr *SecondLdSt,
unsigned NumLoads) const {
// Only cluster up to a single pair.
if (NumLoads > 1)
return false;
if (FirstLdSt->getOpcode() != SecondLdSt->getOpcode())
return false;
// getLdStBaseRegImmOfs guarantees that oper 2 isImm.
unsigned Ofs1 = FirstLdSt->getOperand(2).getImm();
// Allow 6 bits of positive range.
if (Ofs1 > 64)
return false;
// The caller should already have ordered First/SecondLdSt by offset.
unsigned Ofs2 = SecondLdSt->getOperand(2).getImm();
return Ofs1 + 1 == Ofs2;
}
bool ARM64InstrInfo::shouldScheduleAdjacent(MachineInstr *First,
MachineInstr *Second) const {
// Cyclone can fuse CMN, CMP followed by Bcc.
// FIXME: B0 can also fuse:
// AND, BIC, ORN, ORR, or EOR (optional S) followed by Bcc or CBZ or CBNZ.
if (Second->getOpcode() != ARM64::Bcc)
return false;
switch (First->getOpcode()) {
default:
return false;
case ARM64::SUBSWri:
case ARM64::ADDSWri:
case ARM64::ANDSWri:
case ARM64::SUBSXri:
case ARM64::ADDSXri:
case ARM64::ANDSXri:
return true;
}
}
MachineInstr *ARM64InstrInfo::emitFrameIndexDebugValue(MachineFunction &MF,
int FrameIx,
uint64_t Offset,
const MDNode *MDPtr,
DebugLoc DL) const {
MachineInstrBuilder MIB = BuildMI(MF, DL, get(ARM64::DBG_VALUE))
.addFrameIndex(FrameIx)
.addImm(0)
.addImm(Offset)
.addMetadata(MDPtr);
return &*MIB;
}
static const MachineInstrBuilder &AddSubReg(const MachineInstrBuilder &MIB,
unsigned Reg, unsigned SubIdx,
unsigned State,
const TargetRegisterInfo *TRI) {
if (!SubIdx)
return MIB.addReg(Reg, State);
if (TargetRegisterInfo::isPhysicalRegister(Reg))
return MIB.addReg(TRI->getSubReg(Reg, SubIdx), State);
return MIB.addReg(Reg, State, SubIdx);
}
static bool forwardCopyWillClobberTuple(unsigned DestReg, unsigned SrcReg,
unsigned NumRegs) {
// We really want the positive remainder mod 32 here, that happens to be
// easily obtainable with a mask.
return ((DestReg - SrcReg) & 0x1f) < NumRegs;
}
void ARM64InstrInfo::copyPhysRegTuple(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
DebugLoc DL, unsigned DestReg,
unsigned SrcReg, bool KillSrc,
unsigned Opcode,
llvm::ArrayRef<unsigned> Indices) const {
const TargetRegisterInfo *TRI = &getRegisterInfo();
uint16_t DestEncoding = TRI->getEncodingValue(DestReg);
uint16_t SrcEncoding = TRI->getEncodingValue(SrcReg);
unsigned NumRegs = Indices.size();
int SubReg = 0, End = NumRegs, Incr = 1;
if (forwardCopyWillClobberTuple(DestEncoding, SrcEncoding, NumRegs)) {
SubReg = NumRegs - 1;
End = -1;
Incr = -1;
}
for (; SubReg != End; SubReg += Incr) {
const MachineInstrBuilder &MIB = BuildMI(MBB, I, DL, get(Opcode));
AddSubReg(MIB, DestReg, Indices[SubReg], RegState::Define, TRI);
AddSubReg(MIB, SrcReg, Indices[SubReg], 0, TRI);
AddSubReg(MIB, SrcReg, Indices[SubReg], getKillRegState(KillSrc), TRI);
}
}
void ARM64InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I, DebugLoc DL,
unsigned DestReg, unsigned SrcReg,
bool KillSrc) const {
if (ARM64::GPR32spRegClass.contains(DestReg) &&
(ARM64::GPR32spRegClass.contains(SrcReg) || SrcReg == ARM64::WZR)) {
const TargetRegisterInfo *TRI = &getRegisterInfo();
if (DestReg == ARM64::WSP || SrcReg == ARM64::WSP) {
// If either operand is WSP, expand to ADD #0.
if (Subtarget.hasZeroCycleRegMove()) {
// Cyclone recognizes "ADD Xd, Xn, #0" as a zero-cycle register move.
unsigned DestRegX = TRI->getMatchingSuperReg(DestReg, ARM64::sub_32,
&ARM64::GPR64spRegClass);
unsigned SrcRegX = TRI->getMatchingSuperReg(SrcReg, ARM64::sub_32,
&ARM64::GPR64spRegClass);
// This instruction is reading and writing X registers. This may upset
// the register scavenger and machine verifier, so we need to indicate
// that we are reading an undefined value from SrcRegX, but a proper
// value from SrcReg.
BuildMI(MBB, I, DL, get(ARM64::ADDXri), DestRegX)
.addReg(SrcRegX, RegState::Undef)
.addImm(0)
.addImm(ARM64_AM::getShifterImm(ARM64_AM::LSL, 0))
.addReg(SrcReg, RegState::Implicit | getKillRegState(KillSrc));
} else {
BuildMI(MBB, I, DL, get(ARM64::ADDWri), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc))
.addImm(0)
.addImm(ARM64_AM::getShifterImm(ARM64_AM::LSL, 0));
}
} else if (SrcReg == ARM64::WZR && Subtarget.hasZeroCycleZeroing()) {
BuildMI(MBB, I, DL, get(ARM64::MOVZWi), DestReg).addImm(0).addImm(
ARM64_AM::getShifterImm(ARM64_AM::LSL, 0));
} else {
if (Subtarget.hasZeroCycleRegMove()) {
// Cyclone recognizes "ORR Xd, XZR, Xm" as a zero-cycle register move.
unsigned DestRegX = TRI->getMatchingSuperReg(DestReg, ARM64::sub_32,
&ARM64::GPR64spRegClass);
unsigned SrcRegX = TRI->getMatchingSuperReg(SrcReg, ARM64::sub_32,
&ARM64::GPR64spRegClass);
// This instruction is reading and writing X registers. This may upset
// the register scavenger and machine verifier, so we need to indicate
// that we are reading an undefined value from SrcRegX, but a proper
// value from SrcReg.
BuildMI(MBB, I, DL, get(ARM64::ORRXrr), DestRegX)
.addReg(ARM64::XZR)
.addReg(SrcRegX, RegState::Undef)
.addReg(SrcReg, RegState::Implicit | getKillRegState(KillSrc));
} else {
// Otherwise, expand to ORR WZR.
BuildMI(MBB, I, DL, get(ARM64::ORRWrr), DestReg)
.addReg(ARM64::WZR)
.addReg(SrcReg, getKillRegState(KillSrc));
}
}
return;
}
if (ARM64::GPR64spRegClass.contains(DestReg) &&
(ARM64::GPR64spRegClass.contains(SrcReg) || SrcReg == ARM64::XZR)) {
if (DestReg == ARM64::SP || SrcReg == ARM64::SP) {
// If either operand is SP, expand to ADD #0.
BuildMI(MBB, I, DL, get(ARM64::ADDXri), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc))
.addImm(0)
.addImm(ARM64_AM::getShifterImm(ARM64_AM::LSL, 0));
} else if (SrcReg == ARM64::XZR && Subtarget.hasZeroCycleZeroing()) {
BuildMI(MBB, I, DL, get(ARM64::MOVZXi), DestReg).addImm(0).addImm(
ARM64_AM::getShifterImm(ARM64_AM::LSL, 0));
} else {
// Otherwise, expand to ORR XZR.
BuildMI(MBB, I, DL, get(ARM64::ORRXrr), DestReg)
.addReg(ARM64::XZR)
.addReg(SrcReg, getKillRegState(KillSrc));
}
return;
}
// Copy a DDDD register quad by copying the individual sub-registers.
if (ARM64::DDDDRegClass.contains(DestReg) &&
ARM64::DDDDRegClass.contains(SrcReg)) {
static const unsigned Indices[] = { ARM64::dsub0, ARM64::dsub1,
ARM64::dsub2, ARM64::dsub3 };
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, ARM64::ORRv8i8,
Indices);
return;
}
// Copy a DDD register triple by copying the individual sub-registers.
if (ARM64::DDDRegClass.contains(DestReg) &&
ARM64::DDDRegClass.contains(SrcReg)) {
static const unsigned Indices[] = { ARM64::dsub0, ARM64::dsub1,
ARM64::dsub2 };
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, ARM64::ORRv8i8,
Indices);
return;
}
// Copy a DD register pair by copying the individual sub-registers.
if (ARM64::DDRegClass.contains(DestReg) &&
ARM64::DDRegClass.contains(SrcReg)) {
static const unsigned Indices[] = { ARM64::dsub0, ARM64::dsub1 };
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, ARM64::ORRv8i8,
Indices);
return;
}
// Copy a QQQQ register quad by copying the individual sub-registers.
if (ARM64::QQQQRegClass.contains(DestReg) &&
ARM64::QQQQRegClass.contains(SrcReg)) {
static const unsigned Indices[] = { ARM64::qsub0, ARM64::qsub1,
ARM64::qsub2, ARM64::qsub3 };
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, ARM64::ORRv16i8,
Indices);
return;
}
// Copy a QQQ register triple by copying the individual sub-registers.
if (ARM64::QQQRegClass.contains(DestReg) &&
ARM64::QQQRegClass.contains(SrcReg)) {
static const unsigned Indices[] = { ARM64::qsub0, ARM64::qsub1,
ARM64::qsub2 };
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, ARM64::ORRv16i8,
Indices);
return;
}
// Copy a QQ register pair by copying the individual sub-registers.
if (ARM64::QQRegClass.contains(DestReg) &&
ARM64::QQRegClass.contains(SrcReg)) {
static const unsigned Indices[] = { ARM64::qsub0, ARM64::qsub1 };
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, ARM64::ORRv16i8,
Indices);
return;
}
if (ARM64::FPR128RegClass.contains(DestReg) &&
ARM64::FPR128RegClass.contains(SrcReg)) {
BuildMI(MBB, I, DL, get(ARM64::ORRv16i8), DestReg).addReg(SrcReg).addReg(
SrcReg, getKillRegState(KillSrc));
return;
}
if (ARM64::FPR64RegClass.contains(DestReg) &&
ARM64::FPR64RegClass.contains(SrcReg)) {
DestReg =
RI.getMatchingSuperReg(DestReg, ARM64::dsub, &ARM64::FPR128RegClass);
SrcReg =
RI.getMatchingSuperReg(SrcReg, ARM64::dsub, &ARM64::FPR128RegClass);
BuildMI(MBB, I, DL, get(ARM64::ORRv16i8), DestReg).addReg(SrcReg).addReg(
SrcReg, getKillRegState(KillSrc));
return;
}
if (ARM64::FPR32RegClass.contains(DestReg) &&
ARM64::FPR32RegClass.contains(SrcReg)) {
DestReg =
RI.getMatchingSuperReg(DestReg, ARM64::ssub, &ARM64::FPR128RegClass);
SrcReg =
RI.getMatchingSuperReg(SrcReg, ARM64::ssub, &ARM64::FPR128RegClass);
BuildMI(MBB, I, DL, get(ARM64::ORRv16i8), DestReg).addReg(SrcReg).addReg(
SrcReg, getKillRegState(KillSrc));
return;
}
if (ARM64::FPR16RegClass.contains(DestReg) &&
ARM64::FPR16RegClass.contains(SrcReg)) {
DestReg =
RI.getMatchingSuperReg(DestReg, ARM64::hsub, &ARM64::FPR128RegClass);
SrcReg =
RI.getMatchingSuperReg(SrcReg, ARM64::hsub, &ARM64::FPR128RegClass);
BuildMI(MBB, I, DL, get(ARM64::ORRv16i8), DestReg).addReg(SrcReg).addReg(
SrcReg, getKillRegState(KillSrc));
return;
}
if (ARM64::FPR8RegClass.contains(DestReg) &&
ARM64::FPR8RegClass.contains(SrcReg)) {
DestReg =
RI.getMatchingSuperReg(DestReg, ARM64::bsub, &ARM64::FPR128RegClass);
SrcReg =
RI.getMatchingSuperReg(SrcReg, ARM64::bsub, &ARM64::FPR128RegClass);
BuildMI(MBB, I, DL, get(ARM64::ORRv16i8), DestReg).addReg(SrcReg).addReg(
SrcReg, getKillRegState(KillSrc));
return;
}
// Copies between GPR64 and FPR64.
if (ARM64::FPR64RegClass.contains(DestReg) &&
ARM64::GPR64RegClass.contains(SrcReg)) {
BuildMI(MBB, I, DL, get(ARM64::FMOVXDr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
return;
}
if (ARM64::GPR64RegClass.contains(DestReg) &&
ARM64::FPR64RegClass.contains(SrcReg)) {
BuildMI(MBB, I, DL, get(ARM64::FMOVDXr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
return;
}
// Copies between GPR32 and FPR32.
if (ARM64::FPR32RegClass.contains(DestReg) &&
ARM64::GPR32RegClass.contains(SrcReg)) {
BuildMI(MBB, I, DL, get(ARM64::FMOVWSr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
return;
}
if (ARM64::GPR32RegClass.contains(DestReg) &&
ARM64::FPR32RegClass.contains(SrcReg)) {
BuildMI(MBB, I, DL, get(ARM64::FMOVSWr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
return;
}
assert(0 && "unimplemented reg-to-reg copy");
}
void ARM64InstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned SrcReg, bool isKill, int FI,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const {
DebugLoc DL;
if (MBBI != MBB.end())
DL = MBBI->getDebugLoc();
MachineFunction &MF = *MBB.getParent();
MachineFrameInfo &MFI = *MF.getFrameInfo();
unsigned Align = MFI.getObjectAlignment(FI);
MachinePointerInfo PtrInfo(PseudoSourceValue::getFixedStack(FI));
MachineMemOperand *MMO = MF.getMachineMemOperand(
PtrInfo, MachineMemOperand::MOStore, MFI.getObjectSize(FI), Align);
unsigned Opc = 0;
bool Offset = true;
switch (RC->getSize()) {
case 1:
if (ARM64::FPR8RegClass.hasSubClassEq(RC))
Opc = ARM64::STRBui;
break;
case 2:
if (ARM64::FPR16RegClass.hasSubClassEq(RC))
Opc = ARM64::STRHui;
break;
case 4:
if (ARM64::GPR32allRegClass.hasSubClassEq(RC)) {
Opc = ARM64::STRWui;
if (TargetRegisterInfo::isVirtualRegister(SrcReg))
MF.getRegInfo().constrainRegClass(SrcReg, &ARM64::GPR32RegClass);
else
assert(SrcReg != ARM64::WSP);
} else if (ARM64::FPR32RegClass.hasSubClassEq(RC))
Opc = ARM64::STRSui;
break;
case 8:
if (ARM64::GPR64allRegClass.hasSubClassEq(RC)) {
Opc = ARM64::STRXui;
if (TargetRegisterInfo::isVirtualRegister(SrcReg))
MF.getRegInfo().constrainRegClass(SrcReg, &ARM64::GPR64RegClass);
else
assert(SrcReg != ARM64::SP);
} else if (ARM64::FPR64RegClass.hasSubClassEq(RC))
Opc = ARM64::STRDui;
break;
case 16:
if (ARM64::FPR128RegClass.hasSubClassEq(RC))
Opc = ARM64::STRQui;
else if (ARM64::DDRegClass.hasSubClassEq(RC))
Opc = ARM64::ST1Twov1d, Offset = false;
break;
case 24:
if (ARM64::DDDRegClass.hasSubClassEq(RC))
Opc = ARM64::ST1Threev1d, Offset = false;
break;
case 32:
if (ARM64::DDDDRegClass.hasSubClassEq(RC))
Opc = ARM64::ST1Fourv1d, Offset = false;
else if (ARM64::QQRegClass.hasSubClassEq(RC))
Opc = ARM64::ST1Twov2d, Offset = false;
break;
case 48:
if (ARM64::QQQRegClass.hasSubClassEq(RC))
Opc = ARM64::ST1Threev2d, Offset = false;
break;
case 64:
if (ARM64::QQQQRegClass.hasSubClassEq(RC))
Opc = ARM64::ST1Fourv2d, Offset = false;
break;
}
assert(Opc && "Unknown register class");
const MachineInstrBuilder &MI = BuildMI(MBB, MBBI, DL, get(Opc))
.addReg(SrcReg, getKillRegState(isKill))
.addFrameIndex(FI);
if (Offset)
MI.addImm(0);
MI.addMemOperand(MMO);
}
void ARM64InstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned DestReg, int FI,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const {
DebugLoc DL;
if (MBBI != MBB.end())
DL = MBBI->getDebugLoc();
MachineFunction &MF = *MBB.getParent();
MachineFrameInfo &MFI = *MF.getFrameInfo();
unsigned Align = MFI.getObjectAlignment(FI);
MachinePointerInfo PtrInfo(PseudoSourceValue::getFixedStack(FI));
MachineMemOperand *MMO = MF.getMachineMemOperand(
PtrInfo, MachineMemOperand::MOLoad, MFI.getObjectSize(FI), Align);
unsigned Opc = 0;
bool Offset = true;
switch (RC->getSize()) {
case 1:
if (ARM64::FPR8RegClass.hasSubClassEq(RC))
Opc = ARM64::LDRBui;
break;
case 2:
if (ARM64::FPR16RegClass.hasSubClassEq(RC))
Opc = ARM64::LDRHui;
break;
case 4:
if (ARM64::GPR32allRegClass.hasSubClassEq(RC)) {
Opc = ARM64::LDRWui;
if (TargetRegisterInfo::isVirtualRegister(DestReg))
MF.getRegInfo().constrainRegClass(DestReg, &ARM64::GPR32RegClass);
else
assert(DestReg != ARM64::WSP);
} else if (ARM64::FPR32RegClass.hasSubClassEq(RC))
Opc = ARM64::LDRSui;
break;
case 8:
if (ARM64::GPR64allRegClass.hasSubClassEq(RC)) {
Opc = ARM64::LDRXui;
if (TargetRegisterInfo::isVirtualRegister(DestReg))
MF.getRegInfo().constrainRegClass(DestReg, &ARM64::GPR64RegClass);
else
assert(DestReg != ARM64::SP);
} else if (ARM64::FPR64RegClass.hasSubClassEq(RC))
Opc = ARM64::LDRDui;
break;
case 16:
if (ARM64::FPR128RegClass.hasSubClassEq(RC))
Opc = ARM64::LDRQui;
else if (ARM64::DDRegClass.hasSubClassEq(RC))
Opc = ARM64::LD1Twov1d, Offset = false;
break;
case 24:
if (ARM64::DDDRegClass.hasSubClassEq(RC))
Opc = ARM64::LD1Threev1d, Offset = false;
break;
case 32:
if (ARM64::DDDDRegClass.hasSubClassEq(RC))
Opc = ARM64::LD1Fourv1d, Offset = false;
else if (ARM64::QQRegClass.hasSubClassEq(RC))
Opc = ARM64::LD1Twov2d, Offset = false;
break;
case 48:
if (ARM64::QQQRegClass.hasSubClassEq(RC))
Opc = ARM64::LD1Threev2d, Offset = false;
break;
case 64:
if (ARM64::QQQQRegClass.hasSubClassEq(RC))
Opc = ARM64::LD1Fourv2d, Offset = false;
break;
}
assert(Opc && "Unknown register class");
const MachineInstrBuilder &MI = BuildMI(MBB, MBBI, DL, get(Opc))
.addReg(DestReg, getDefRegState(true))
.addFrameIndex(FI);
if (Offset)
MI.addImm(0);
MI.addMemOperand(MMO);
}
void llvm::emitFrameOffset(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, DebugLoc DL,
unsigned DestReg, unsigned SrcReg, int Offset,
const ARM64InstrInfo *TII, MachineInstr::MIFlag Flag,
bool SetCPSR) {
if (DestReg == SrcReg && Offset == 0)
return;
bool isSub = Offset < 0;
if (isSub)
Offset = -Offset;
// FIXME: If the offset won't fit in 24-bits, compute the offset into a
// scratch register. If DestReg is a virtual register, use it as the
// scratch register; otherwise, create a new virtual register (to be
// replaced by the scavenger at the end of PEI). That case can be optimized
// slightly if DestReg is SP which is always 16-byte aligned, so the scratch
// register can be loaded with offset%8 and the add/sub can use an extending
// instruction with LSL#3.
// Currently the function handles any offsets but generates a poor sequence
// of code.
// assert(Offset < (1 << 24) && "unimplemented reg plus immediate");
unsigned Opc;
if (SetCPSR)
Opc = isSub ? ARM64::SUBSXri : ARM64::ADDSXri;
else
Opc = isSub ? ARM64::SUBXri : ARM64::ADDXri;
const unsigned MaxEncoding = 0xfff;
const unsigned ShiftSize = 12;
const unsigned MaxEncodableValue = MaxEncoding << ShiftSize;
while (((unsigned)Offset) >= (1 << ShiftSize)) {
unsigned ThisVal;
if (((unsigned)Offset) > MaxEncodableValue) {
ThisVal = MaxEncodableValue;
} else {
ThisVal = Offset & MaxEncodableValue;
}
assert((ThisVal >> ShiftSize) <= MaxEncoding &&
"Encoding cannot handle value that big");
BuildMI(MBB, MBBI, DL, TII->get(Opc), DestReg)
.addReg(SrcReg)
.addImm(ThisVal >> ShiftSize)
.addImm(ARM64_AM::getShifterImm(ARM64_AM::LSL, ShiftSize))
.setMIFlag(Flag);
SrcReg = DestReg;
Offset -= ThisVal;
if (Offset == 0)
return;
}
BuildMI(MBB, MBBI, DL, TII->get(Opc), DestReg)
.addReg(SrcReg)
.addImm(Offset)
.addImm(ARM64_AM::getShifterImm(ARM64_AM::LSL, 0))
.setMIFlag(Flag);
}
MachineInstr *
ARM64InstrInfo::foldMemoryOperandImpl(MachineFunction &MF, MachineInstr *MI,
const SmallVectorImpl<unsigned> &Ops,
int FrameIndex) const {
// This is a bit of a hack. Consider this instruction:
//
// %vreg0<def> = COPY %SP; GPR64all:%vreg0
//
// We explicitly chose GPR64all for the virtual register so such a copy might
// be eliminated by RegisterCoalescer. However, that may not be possible, and
// %vreg0 may even spill. We can't spill %SP, and since it is in the GPR64all
// register class, TargetInstrInfo::foldMemoryOperand() is going to try.
//
// To prevent that, we are going to constrain the %vreg0 register class here.
//
// <rdar://problem/11522048>
//
if (MI->isCopy()) {
unsigned DstReg = MI->getOperand(0).getReg();
unsigned SrcReg = MI->getOperand(1).getReg();
if (SrcReg == ARM64::SP && TargetRegisterInfo::isVirtualRegister(DstReg)) {
MF.getRegInfo().constrainRegClass(DstReg, &ARM64::GPR64RegClass);
return 0;
}
if (DstReg == ARM64::SP && TargetRegisterInfo::isVirtualRegister(SrcReg)) {
MF.getRegInfo().constrainRegClass(SrcReg, &ARM64::GPR64RegClass);
return 0;
}
}
// Cannot fold.
return 0;
}
int llvm::isARM64FrameOffsetLegal(const MachineInstr &MI, int &Offset,
bool *OutUseUnscaledOp,
unsigned *OutUnscaledOp,
int *EmittableOffset) {
int Scale = 1;
bool IsSigned = false;
// The ImmIdx should be changed case by case if it is not 2.
unsigned ImmIdx = 2;
unsigned UnscaledOp = 0;
// Set output values in case of early exit.
if (EmittableOffset)
*EmittableOffset = 0;
if (OutUseUnscaledOp)
*OutUseUnscaledOp = false;
if (OutUnscaledOp)
*OutUnscaledOp = 0;
switch (MI.getOpcode()) {
default:
assert(0 && "unhandled opcode in rewriteARM64FrameIndex");
// Vector spills/fills can't take an immediate offset.
case ARM64::LD1Twov2d:
case ARM64::LD1Threev2d:
case ARM64::LD1Fourv2d:
case ARM64::LD1Twov1d:
case ARM64::LD1Threev1d:
case ARM64::LD1Fourv1d:
case ARM64::ST1Twov2d:
case ARM64::ST1Threev2d:
case ARM64::ST1Fourv2d:
case ARM64::ST1Twov1d:
case ARM64::ST1Threev1d:
case ARM64::ST1Fourv1d:
return ARM64FrameOffsetCannotUpdate;
case ARM64::PRFMui:
Scale = 8;
UnscaledOp = ARM64::PRFUMi;
break;
case ARM64::LDRXui:
Scale = 8;
UnscaledOp = ARM64::LDURXi;
break;
case ARM64::LDRWui:
Scale = 4;
UnscaledOp = ARM64::LDURWi;
break;
case ARM64::LDRBui:
Scale = 1;
UnscaledOp = ARM64::LDURBi;
break;
case ARM64::LDRHui:
Scale = 2;
UnscaledOp = ARM64::LDURHi;
break;
case ARM64::LDRSui:
Scale = 4;
UnscaledOp = ARM64::LDURSi;
break;
case ARM64::LDRDui:
Scale = 8;
UnscaledOp = ARM64::LDURDi;
break;
case ARM64::LDRQui:
Scale = 16;
UnscaledOp = ARM64::LDURQi;
break;
case ARM64::LDRBBui:
Scale = 1;
UnscaledOp = ARM64::LDURBBi;
break;
case ARM64::LDRHHui:
Scale = 2;
UnscaledOp = ARM64::LDURHHi;
break;
case ARM64::LDRSBXui:
Scale = 1;
UnscaledOp = ARM64::LDURSBXi;
break;
case ARM64::LDRSBWui:
Scale = 1;
UnscaledOp = ARM64::LDURSBWi;
break;
case ARM64::LDRSHXui:
Scale = 2;
UnscaledOp = ARM64::LDURSHXi;
break;
case ARM64::LDRSHWui:
Scale = 2;
UnscaledOp = ARM64::LDURSHWi;
break;
case ARM64::LDRSWui:
Scale = 4;
UnscaledOp = ARM64::LDURSWi;
break;
case ARM64::STRXui:
Scale = 8;
UnscaledOp = ARM64::STURXi;
break;
case ARM64::STRWui:
Scale = 4;
UnscaledOp = ARM64::STURWi;
break;
case ARM64::STRBui:
Scale = 1;
UnscaledOp = ARM64::STURBi;
break;
case ARM64::STRHui:
Scale = 2;
UnscaledOp = ARM64::STURHi;
break;
case ARM64::STRSui:
Scale = 4;
UnscaledOp = ARM64::STURSi;
break;
case ARM64::STRDui:
Scale = 8;
UnscaledOp = ARM64::STURDi;
break;
case ARM64::STRQui:
Scale = 16;
UnscaledOp = ARM64::STURQi;
break;
case ARM64::STRBBui:
Scale = 1;
UnscaledOp = ARM64::STURBBi;
break;
case ARM64::STRHHui:
Scale = 2;
UnscaledOp = ARM64::STURHHi;
break;
case ARM64::LDPXi:
case ARM64::LDPDi:
case ARM64::STPXi:
case ARM64::STPDi:
IsSigned = true;
Scale = 8;
break;
case ARM64::LDPQi:
case ARM64::STPQi:
IsSigned = true;
Scale = 16;
break;
case ARM64::LDPWi:
case ARM64::LDPSi:
case ARM64::STPWi:
case ARM64::STPSi:
IsSigned = true;
Scale = 4;
break;
case ARM64::LDURXi:
case ARM64::LDURWi:
case ARM64::LDURBi:
case ARM64::LDURHi:
case ARM64::LDURSi:
case ARM64::LDURDi:
case ARM64::LDURQi:
case ARM64::LDURHHi:
case ARM64::LDURBBi:
case ARM64::LDURSBXi:
case ARM64::LDURSBWi:
case ARM64::LDURSHXi:
case ARM64::LDURSHWi:
case ARM64::LDURSWi:
case ARM64::STURXi:
case ARM64::STURWi:
case ARM64::STURBi:
case ARM64::STURHi:
case ARM64::STURSi:
case ARM64::STURDi:
case ARM64::STURQi:
case ARM64::STURBBi:
case ARM64::STURHHi:
Scale = 1;
break;
}
Offset += MI.getOperand(ImmIdx).getImm() * Scale;
bool useUnscaledOp = false;
// If the offset doesn't match the scale, we rewrite the instruction to
// use the unscaled instruction instead. Likewise, if we have a negative
// offset (and have an unscaled op to use).
if ((Offset & (Scale - 1)) != 0 || (Offset < 0 && UnscaledOp != 0))
useUnscaledOp = true;
// Use an unscaled addressing mode if the instruction has a negative offset
// (or if the instruction is already using an unscaled addressing mode).
unsigned MaskBits;
if (IsSigned) {
// ldp/stp instructions.
MaskBits = 7;
Offset /= Scale;
} else if (UnscaledOp == 0 || useUnscaledOp) {
MaskBits = 9;
IsSigned = true;
Scale = 1;
} else {
MaskBits = 12;
IsSigned = false;
Offset /= Scale;
}
// Attempt to fold address computation.
int MaxOff = (1 << (MaskBits - IsSigned)) - 1;
int MinOff = (IsSigned ? (-MaxOff - 1) : 0);
if (Offset >= MinOff && Offset <= MaxOff) {
if (EmittableOffset)
*EmittableOffset = Offset;
Offset = 0;
} else {
int NewOff = Offset < 0 ? MinOff : MaxOff;
if (EmittableOffset)
*EmittableOffset = NewOff;
Offset = (Offset - NewOff) * Scale;
}
if (OutUseUnscaledOp)
*OutUseUnscaledOp = useUnscaledOp;
if (OutUnscaledOp)
*OutUnscaledOp = UnscaledOp;
return ARM64FrameOffsetCanUpdate |
(Offset == 0 ? ARM64FrameOffsetIsLegal : 0);
}
bool llvm::rewriteARM64FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
unsigned FrameReg, int &Offset,
const ARM64InstrInfo *TII) {
unsigned Opcode = MI.getOpcode();
unsigned ImmIdx = FrameRegIdx + 1;
if (Opcode == ARM64::ADDSXri || Opcode == ARM64::ADDXri) {
Offset += MI.getOperand(ImmIdx).getImm();
emitFrameOffset(*MI.getParent(), MI, MI.getDebugLoc(),
MI.getOperand(0).getReg(), FrameReg, Offset, TII,
MachineInstr::NoFlags, (Opcode == ARM64::ADDSXri));
MI.eraseFromParent();
Offset = 0;
return true;
}
int NewOffset;
unsigned UnscaledOp;
bool UseUnscaledOp;
int Status = isARM64FrameOffsetLegal(MI, Offset, &UseUnscaledOp, &UnscaledOp,
&NewOffset);
if (Status & ARM64FrameOffsetCanUpdate) {
if (Status & ARM64FrameOffsetIsLegal)
// Replace the FrameIndex with FrameReg.
MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
if (UseUnscaledOp)
MI.setDesc(TII->get(UnscaledOp));
MI.getOperand(ImmIdx).ChangeToImmediate(NewOffset);
return Offset == 0;
}
return false;
}
void ARM64InstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
NopInst.setOpcode(ARM64::HINT);
NopInst.addOperand(MCOperand::CreateImm(0));
}
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