blob: 54f3f7c101324f4b7f38bf55f0780a7a29ede033 [file] [log] [blame]
//===- AArch64InstrInfo.cpp - AArch64 Instruction Information -------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains the AArch64 implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "AArch64InstrInfo.h"
#include "AArch64MachineFunctionInfo.h"
#include "AArch64Subtarget.h"
#include "MCTargetDesc/AArch64AddressingModes.h"
#include "Utils/AArch64BaseInfo.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/StackMaps.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <cassert>
#include <cstdint>
#include <iterator>
#include <utility>
using namespace llvm;
#define GET_INSTRINFO_CTOR_DTOR
#include "AArch64GenInstrInfo.inc"
static cl::opt<unsigned> TBZDisplacementBits(
"aarch64-tbz-offset-bits", cl::Hidden, cl::init(14),
cl::desc("Restrict range of TB[N]Z instructions (DEBUG)"));
static cl::opt<unsigned> CBZDisplacementBits(
"aarch64-cbz-offset-bits", cl::Hidden, cl::init(19),
cl::desc("Restrict range of CB[N]Z instructions (DEBUG)"));
static cl::opt<unsigned>
BCCDisplacementBits("aarch64-bcc-offset-bits", cl::Hidden, cl::init(19),
cl::desc("Restrict range of Bcc instructions (DEBUG)"));
AArch64InstrInfo::AArch64InstrInfo(const AArch64Subtarget &STI)
: AArch64GenInstrInfo(AArch64::ADJCALLSTACKDOWN, AArch64::ADJCALLSTACKUP,
AArch64::CATCHRET),
RI(STI.getTargetTriple()), Subtarget(STI) {}
/// GetInstSize - Return the number of bytes of code the specified
/// instruction may be. This returns the maximum number of bytes.
unsigned AArch64InstrInfo::getInstSizeInBytes(const MachineInstr &MI) const {
const MachineBasicBlock &MBB = *MI.getParent();
const MachineFunction *MF = MBB.getParent();
const MCAsmInfo *MAI = MF->getTarget().getMCAsmInfo();
{
auto Op = MI.getOpcode();
if (Op == AArch64::INLINEASM || Op == AArch64::INLINEASM_BR)
return getInlineAsmLength(MI.getOperand(0).getSymbolName(), *MAI);
}
// Meta-instructions emit no code.
if (MI.isMetaInstruction())
return 0;
// FIXME: We currently only handle pseudoinstructions that don't get expanded
// before the assembly printer.
unsigned NumBytes = 0;
const MCInstrDesc &Desc = MI.getDesc();
switch (Desc.getOpcode()) {
default:
// Anything not explicitly designated otherwise is a normal 4-byte insn.
NumBytes = 4;
break;
case TargetOpcode::STACKMAP:
// The upper bound for a stackmap intrinsic is the full length of its shadow
NumBytes = StackMapOpers(&MI).getNumPatchBytes();
assert(NumBytes % 4 == 0 && "Invalid number of NOP bytes requested!");
break;
case TargetOpcode::PATCHPOINT:
// The size of the patchpoint intrinsic is the number of bytes requested
NumBytes = PatchPointOpers(&MI).getNumPatchBytes();
assert(NumBytes % 4 == 0 && "Invalid number of NOP bytes requested!");
break;
case AArch64::TLSDESC_CALLSEQ:
// This gets lowered to an instruction sequence which takes 16 bytes
NumBytes = 16;
break;
case AArch64::JumpTableDest32:
case AArch64::JumpTableDest16:
case AArch64::JumpTableDest8:
NumBytes = 12;
break;
case AArch64::SPACE:
NumBytes = MI.getOperand(1).getImm();
break;
}
return NumBytes;
}
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 AArch64::Bcc:
Target = LastInst->getOperand(1).getMBB();
Cond.push_back(LastInst->getOperand(0));
break;
case AArch64::CBZW:
case AArch64::CBZX:
case AArch64::CBNZW:
case AArch64::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 AArch64::TBZW:
case AArch64::TBZX:
case AArch64::TBNZW:
case AArch64::TBNZX:
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));
}
}
static unsigned getBranchDisplacementBits(unsigned Opc) {
switch (Opc) {
default:
llvm_unreachable("unexpected opcode!");
case AArch64::B:
return 64;
case AArch64::TBNZW:
case AArch64::TBZW:
case AArch64::TBNZX:
case AArch64::TBZX:
return TBZDisplacementBits;
case AArch64::CBNZW:
case AArch64::CBZW:
case AArch64::CBNZX:
case AArch64::CBZX:
return CBZDisplacementBits;
case AArch64::Bcc:
return BCCDisplacementBits;
}
}
bool AArch64InstrInfo::isBranchOffsetInRange(unsigned BranchOp,
int64_t BrOffset) const {
unsigned Bits = getBranchDisplacementBits(BranchOp);
assert(Bits >= 3 && "max branch displacement must be enough to jump"
"over conditional branch expansion");
return isIntN(Bits, BrOffset / 4);
}
MachineBasicBlock *
AArch64InstrInfo::getBranchDestBlock(const MachineInstr &MI) const {
switch (MI.getOpcode()) {
default:
llvm_unreachable("unexpected opcode!");
case AArch64::B:
return MI.getOperand(0).getMBB();
case AArch64::TBZW:
case AArch64::TBNZW:
case AArch64::TBZX:
case AArch64::TBNZX:
return MI.getOperand(2).getMBB();
case AArch64::CBZW:
case AArch64::CBNZW:
case AArch64::CBZX:
case AArch64::CBNZX:
case AArch64::Bcc:
return MI.getOperand(1).getMBB();
}
}
// Branch analysis.
bool AArch64InstrInfo::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.getLastNonDebugInstr();
if (I == MBB.end())
return false;
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 AArch64InstrInfo::reverseBranchCondition(
SmallVectorImpl<MachineOperand> &Cond) const {
if (Cond[0].getImm() != -1) {
// Regular Bcc
AArch64CC::CondCode CC = (AArch64CC::CondCode)(int)Cond[0].getImm();
Cond[0].setImm(AArch64CC::getInvertedCondCode(CC));
} else {
// Folded compare-and-branch
switch (Cond[1].getImm()) {
default:
llvm_unreachable("Unknown conditional branch!");
case AArch64::CBZW:
Cond[1].setImm(AArch64::CBNZW);
break;
case AArch64::CBNZW:
Cond[1].setImm(AArch64::CBZW);
break;
case AArch64::CBZX:
Cond[1].setImm(AArch64::CBNZX);
break;
case AArch64::CBNZX:
Cond[1].setImm(AArch64::CBZX);
break;
case AArch64::TBZW:
Cond[1].setImm(AArch64::TBNZW);
break;
case AArch64::TBNZW:
Cond[1].setImm(AArch64::TBZW);
break;
case AArch64::TBZX:
Cond[1].setImm(AArch64::TBNZX);
break;
case AArch64::TBNZX:
Cond[1].setImm(AArch64::TBZX);
break;
}
}
return false;
}
unsigned AArch64InstrInfo::removeBranch(MachineBasicBlock &MBB,
int *BytesRemoved) const {
MachineBasicBlock::iterator I = MBB.getLastNonDebugInstr();
if (I == MBB.end())
return 0;
if (!isUncondBranchOpcode(I->getOpcode()) &&
!isCondBranchOpcode(I->getOpcode()))
return 0;
// Remove the branch.
I->eraseFromParent();
I = MBB.end();
if (I == MBB.begin()) {
if (BytesRemoved)
*BytesRemoved = 4;
return 1;
}
--I;
if (!isCondBranchOpcode(I->getOpcode())) {
if (BytesRemoved)
*BytesRemoved = 4;
return 1;
}
// Remove the branch.
I->eraseFromParent();
if (BytesRemoved)
*BytesRemoved = 8;
return 2;
}
void AArch64InstrInfo::instantiateCondBranch(
MachineBasicBlock &MBB, const DebugLoc &DL, MachineBasicBlock *TBB,
ArrayRef<MachineOperand> Cond) const {
if (Cond[0].getImm() != -1) {
// Regular Bcc
BuildMI(&MBB, DL, get(AArch64::Bcc)).addImm(Cond[0].getImm()).addMBB(TBB);
} else {
// Folded compare-and-branch
// Note that we use addOperand instead of addReg to keep the flags.
const MachineInstrBuilder MIB =
BuildMI(&MBB, DL, get(Cond[1].getImm())).add(Cond[2]);
if (Cond.size() > 3)
MIB.addImm(Cond[3].getImm());
MIB.addMBB(TBB);
}
}
unsigned AArch64InstrInfo::insertBranch(
MachineBasicBlock &MBB, MachineBasicBlock *TBB, MachineBasicBlock *FBB,
ArrayRef<MachineOperand> Cond, const DebugLoc &DL, int *BytesAdded) const {
// Shouldn't be a fall through.
assert(TBB && "insertBranch must not be told to insert a fallthrough");
if (!FBB) {
if (Cond.empty()) // Unconditional branch?
BuildMI(&MBB, DL, get(AArch64::B)).addMBB(TBB);
else
instantiateCondBranch(MBB, DL, TBB, Cond);
if (BytesAdded)
*BytesAdded = 4;
return 1;
}
// Two-way conditional branch.
instantiateCondBranch(MBB, DL, TBB, Cond);
BuildMI(&MBB, DL, get(AArch64::B)).addMBB(FBB);
if (BytesAdded)
*BytesAdded = 8;
return 2;
}
// Find the original register that VReg is copied from.
static unsigned removeCopies(const MachineRegisterInfo &MRI, unsigned VReg) {
while (Register::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 = nullptr) {
VReg = removeCopies(MRI, VReg);
if (!Register::isVirtualRegister(VReg))
return 0;
bool Is64Bit = AArch64::GPR64allRegClass.hasSubClassEq(MRI.getRegClass(VReg));
const MachineInstr *DefMI = MRI.getVRegDef(VReg);
unsigned Opc = 0;
unsigned SrcOpNum = 0;
switch (DefMI->getOpcode()) {
case AArch64::ADDSXri:
case AArch64::ADDSWri:
// if NZCV is used, do not fold.
if (DefMI->findRegisterDefOperandIdx(AArch64::NZCV, true) == -1)
return 0;
// fall-through to ADDXri and ADDWri.
LLVM_FALLTHROUGH;
case AArch64::ADDXri:
case AArch64::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 ? AArch64::CSINCXr : AArch64::CSINCWr;
break;
case AArch64::ORNXrr:
case AArch64::ORNWrr: {
// not x -> csinv, represented as orn dst, xzr, src.
unsigned ZReg = removeCopies(MRI, DefMI->getOperand(1).getReg());
if (ZReg != AArch64::XZR && ZReg != AArch64::WZR)
return 0;
SrcOpNum = 2;
Opc = Is64Bit ? AArch64::CSINVXr : AArch64::CSINVWr;
break;
}
case AArch64::SUBSXrr:
case AArch64::SUBSWrr:
// if NZCV is used, do not fold.
if (DefMI->findRegisterDefOperandIdx(AArch64::NZCV, true) == -1)
return 0;
// fall-through to SUBXrr and SUBWrr.
LLVM_FALLTHROUGH;
case AArch64::SUBXrr:
case AArch64::SUBWrr: {
// neg x -> csneg, represented as sub dst, xzr, src.
unsigned ZReg = removeCopies(MRI, DefMI->getOperand(1).getReg());
if (ZReg != AArch64::XZR && ZReg != AArch64::WZR)
return 0;
SrcOpNum = 2;
Opc = Is64Bit ? AArch64::CSNEGXr : AArch64::CSNEGWr;
break;
}
default:
return 0;
}
assert(Opc && SrcOpNum && "Missing parameters");
if (NewVReg)
*NewVReg = DefMI->getOperand(SrcOpNum).getReg();
return Opc;
}
bool AArch64InstrInfo::canInsertSelect(const MachineBasicBlock &MBB,
ArrayRef<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 (AArch64::GPR64allRegClass.hasSubClassEq(RC) ||
AArch64::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 (AArch64::FPR64RegClass.hasSubClassEq(RC) ||
AArch64::FPR32RegClass.hasSubClassEq(RC)) {
CondCycles = 5 + ExtraCondLat;
TrueCycles = FalseCycles = 2;
return true;
}
// Can't do vectors.
return false;
}
void AArch64InstrInfo::insertSelect(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
const DebugLoc &DL, unsigned DstReg,
ArrayRef<MachineOperand> Cond,
unsigned TrueReg, unsigned FalseReg) const {
MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
// Parse the condition code, see parseCondBranch() above.
AArch64CC::CondCode CC;
switch (Cond.size()) {
default:
llvm_unreachable("Unknown condition opcode in Cond");
case 1: // b.cc
CC = AArch64CC::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 AArch64::CBZW:
Is64Bit = false;
CC = AArch64CC::EQ;
break;
case AArch64::CBZX:
Is64Bit = true;
CC = AArch64CC::EQ;
break;
case AArch64::CBNZW:
Is64Bit = false;
CC = AArch64CC::NE;
break;
case AArch64::CBNZX:
Is64Bit = true;
CC = AArch64CC::NE;
break;
}
Register SrcReg = Cond[2].getReg();
if (Is64Bit) {
// cmp reg, #0 is actually subs xzr, reg, #0.
MRI.constrainRegClass(SrcReg, &AArch64::GPR64spRegClass);
BuildMI(MBB, I, DL, get(AArch64::SUBSXri), AArch64::XZR)
.addReg(SrcReg)
.addImm(0)
.addImm(0);
} else {
MRI.constrainRegClass(SrcReg, &AArch64::GPR32spRegClass);
BuildMI(MBB, I, DL, get(AArch64::SUBSWri), AArch64::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 AArch64::TBZW:
case AArch64::TBZX:
CC = AArch64CC::EQ;
break;
case AArch64::TBNZW:
case AArch64::TBNZX:
CC = AArch64CC::NE;
break;
}
// cmp reg, #foo is actually ands xzr, reg, #1<<foo.
if (Cond[1].getImm() == AArch64::TBZW || Cond[1].getImm() == AArch64::TBNZW)
BuildMI(MBB, I, DL, get(AArch64::ANDSWri), AArch64::WZR)
.addReg(Cond[2].getReg())
.addImm(
AArch64_AM::encodeLogicalImmediate(1ull << Cond[3].getImm(), 32));
else
BuildMI(MBB, I, DL, get(AArch64::ANDSXri), AArch64::XZR)
.addReg(Cond[2].getReg())
.addImm(
AArch64_AM::encodeLogicalImmediate(1ull << Cond[3].getImm(), 64));
break;
}
}
unsigned Opc = 0;
const TargetRegisterClass *RC = nullptr;
bool TryFold = false;
if (MRI.constrainRegClass(DstReg, &AArch64::GPR64RegClass)) {
RC = &AArch64::GPR64RegClass;
Opc = AArch64::CSELXr;
TryFold = true;
} else if (MRI.constrainRegClass(DstReg, &AArch64::GPR32RegClass)) {
RC = &AArch64::GPR32RegClass;
Opc = AArch64::CSELWr;
TryFold = true;
} else if (MRI.constrainRegClass(DstReg, &AArch64::FPR64RegClass)) {
RC = &AArch64::FPR64RegClass;
Opc = AArch64::FCSELDrrr;
} else if (MRI.constrainRegClass(DstReg, &AArch64::FPR32RegClass)) {
RC = &AArch64::FPR32RegClass;
Opc = AArch64::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 = AArch64CC::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);
}
/// Returns true if a MOVi32imm or MOVi64imm can be expanded to an ORRxx.
static bool canBeExpandedToORR(const MachineInstr &MI, unsigned BitSize) {
uint64_t Imm = MI.getOperand(1).getImm();
uint64_t UImm = Imm << (64 - BitSize) >> (64 - BitSize);
uint64_t Encoding;
return AArch64_AM::processLogicalImmediate(UImm, BitSize, Encoding);
}
// FIXME: this implementation should be micro-architecture dependent, so a
// micro-architecture target hook should be introduced here in future.
bool AArch64InstrInfo::isAsCheapAsAMove(const MachineInstr &MI) const {
if (!Subtarget.hasCustomCheapAsMoveHandling())
return MI.isAsCheapAsAMove();
const unsigned Opcode = MI.getOpcode();
// Firstly, check cases gated by features.
if (Subtarget.hasZeroCycleZeroingFP()) {
if (Opcode == AArch64::FMOVH0 ||
Opcode == AArch64::FMOVS0 ||
Opcode == AArch64::FMOVD0)
return true;
}
if (Subtarget.hasZeroCycleZeroingGP()) {
if (Opcode == TargetOpcode::COPY &&
(MI.getOperand(1).getReg() == AArch64::WZR ||
MI.getOperand(1).getReg() == AArch64::XZR))
return true;
}
// Secondly, check cases specific to sub-targets.
if (Subtarget.hasExynosCheapAsMoveHandling()) {
if (isExynosCheapAsMove(MI))
return true;
return MI.isAsCheapAsAMove();
}
// Finally, check generic cases.
switch (Opcode) {
default:
return false;
// add/sub on register without shift
case AArch64::ADDWri:
case AArch64::ADDXri:
case AArch64::SUBWri:
case AArch64::SUBXri:
return (MI.getOperand(3).getImm() == 0);
// logical ops on immediate
case AArch64::ANDWri:
case AArch64::ANDXri:
case AArch64::EORWri:
case AArch64::EORXri:
case AArch64::ORRWri:
case AArch64::ORRXri:
return true;
// logical ops on register without shift
case AArch64::ANDWrr:
case AArch64::ANDXrr:
case AArch64::BICWrr:
case AArch64::BICXrr:
case AArch64::EONWrr:
case AArch64::EONXrr:
case AArch64::EORWrr:
case AArch64::EORXrr:
case AArch64::ORNWrr:
case AArch64::ORNXrr:
case AArch64::ORRWrr:
case AArch64::ORRXrr:
return true;
// If MOVi32imm or MOVi64imm can be expanded into ORRWri or
// ORRXri, it is as cheap as MOV
case AArch64::MOVi32imm:
return canBeExpandedToORR(MI, 32);
case AArch64::MOVi64imm:
return canBeExpandedToORR(MI, 64);
}
llvm_unreachable("Unknown opcode to check as cheap as a move!");
}
bool AArch64InstrInfo::isFalkorShiftExtFast(const MachineInstr &MI) {
switch (MI.getOpcode()) {
default:
return false;
case AArch64::ADDWrs:
case AArch64::ADDXrs:
case AArch64::ADDSWrs:
case AArch64::ADDSXrs: {
unsigned Imm = MI.getOperand(3).getImm();
unsigned ShiftVal = AArch64_AM::getShiftValue(Imm);
if (ShiftVal == 0)
return true;
return AArch64_AM::getShiftType(Imm) == AArch64_AM::LSL && ShiftVal <= 5;
}
case AArch64::ADDWrx:
case AArch64::ADDXrx:
case AArch64::ADDXrx64:
case AArch64::ADDSWrx:
case AArch64::ADDSXrx:
case AArch64::ADDSXrx64: {
unsigned Imm = MI.getOperand(3).getImm();
switch (AArch64_AM::getArithExtendType(Imm)) {
default:
return false;
case AArch64_AM::UXTB:
case AArch64_AM::UXTH:
case AArch64_AM::UXTW:
case AArch64_AM::UXTX:
return AArch64_AM::getArithShiftValue(Imm) <= 4;
}
}
case AArch64::SUBWrs:
case AArch64::SUBSWrs: {
unsigned Imm = MI.getOperand(3).getImm();
unsigned ShiftVal = AArch64_AM::getShiftValue(Imm);
return ShiftVal == 0 ||
(AArch64_AM::getShiftType(Imm) == AArch64_AM::ASR && ShiftVal == 31);
}
case AArch64::SUBXrs:
case AArch64::SUBSXrs: {
unsigned Imm = MI.getOperand(3).getImm();
unsigned ShiftVal = AArch64_AM::getShiftValue(Imm);
return ShiftVal == 0 ||
(AArch64_AM::getShiftType(Imm) == AArch64_AM::ASR && ShiftVal == 63);
}
case AArch64::SUBWrx:
case AArch64::SUBXrx:
case AArch64::SUBXrx64:
case AArch64::SUBSWrx:
case AArch64::SUBSXrx:
case AArch64::SUBSXrx64: {
unsigned Imm = MI.getOperand(3).getImm();
switch (AArch64_AM::getArithExtendType(Imm)) {
default:
return false;
case AArch64_AM::UXTB:
case AArch64_AM::UXTH:
case AArch64_AM::UXTW:
case AArch64_AM::UXTX:
return AArch64_AM::getArithShiftValue(Imm) == 0;
}
}
case AArch64::LDRBBroW:
case AArch64::LDRBBroX:
case AArch64::LDRBroW:
case AArch64::LDRBroX:
case AArch64::LDRDroW:
case AArch64::LDRDroX:
case AArch64::LDRHHroW:
case AArch64::LDRHHroX:
case AArch64::LDRHroW:
case AArch64::LDRHroX:
case AArch64::LDRQroW:
case AArch64::LDRQroX:
case AArch64::LDRSBWroW:
case AArch64::LDRSBWroX:
case AArch64::LDRSBXroW:
case AArch64::LDRSBXroX:
case AArch64::LDRSHWroW:
case AArch64::LDRSHWroX:
case AArch64::LDRSHXroW:
case AArch64::LDRSHXroX:
case AArch64::LDRSWroW:
case AArch64::LDRSWroX:
case AArch64::LDRSroW:
case AArch64::LDRSroX:
case AArch64::LDRWroW:
case AArch64::LDRWroX:
case AArch64::LDRXroW:
case AArch64::LDRXroX:
case AArch64::PRFMroW:
case AArch64::PRFMroX:
case AArch64::STRBBroW:
case AArch64::STRBBroX:
case AArch64::STRBroW:
case AArch64::STRBroX:
case AArch64::STRDroW:
case AArch64::STRDroX:
case AArch64::STRHHroW:
case AArch64::STRHHroX:
case AArch64::STRHroW:
case AArch64::STRHroX:
case AArch64::STRQroW:
case AArch64::STRQroX:
case AArch64::STRSroW:
case AArch64::STRSroX:
case AArch64::STRWroW:
case AArch64::STRWroX:
case AArch64::STRXroW:
case AArch64::STRXroX: {
unsigned IsSigned = MI.getOperand(3).getImm();
return !IsSigned;
}
}
}
bool AArch64InstrInfo::isSEHInstruction(const MachineInstr &MI) {
unsigned Opc = MI.getOpcode();
switch (Opc) {
default:
return false;
case AArch64::SEH_StackAlloc:
case AArch64::SEH_SaveFPLR:
case AArch64::SEH_SaveFPLR_X:
case AArch64::SEH_SaveReg:
case AArch64::SEH_SaveReg_X:
case AArch64::SEH_SaveRegP:
case AArch64::SEH_SaveRegP_X:
case AArch64::SEH_SaveFReg:
case AArch64::SEH_SaveFReg_X:
case AArch64::SEH_SaveFRegP:
case AArch64::SEH_SaveFRegP_X:
case AArch64::SEH_SetFP:
case AArch64::SEH_AddFP:
case AArch64::SEH_Nop:
case AArch64::SEH_PrologEnd:
case AArch64::SEH_EpilogStart:
case AArch64::SEH_EpilogEnd:
return true;
}
}
bool AArch64InstrInfo::isCoalescableExtInstr(const MachineInstr &MI,
unsigned &SrcReg, unsigned &DstReg,
unsigned &SubIdx) const {
switch (MI.getOpcode()) {
default:
return false;
case AArch64::SBFMXri: // aka sxtw
case AArch64::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 = AArch64::sub_32;
return true;
}
}
bool AArch64InstrInfo::areMemAccessesTriviallyDisjoint(
const MachineInstr &MIa, const MachineInstr &MIb) const {
const TargetRegisterInfo *TRI = &getRegisterInfo();
const MachineOperand *BaseOpA = nullptr, *BaseOpB = nullptr;
int64_t OffsetA = 0, OffsetB = 0;
unsigned WidthA = 0, WidthB = 0;
assert(MIa.mayLoadOrStore() && "MIa must be a load or store.");
assert(MIb.mayLoadOrStore() && "MIb must be a load or store.");
if (MIa.hasUnmodeledSideEffects() || MIb.hasUnmodeledSideEffects() ||
MIa.hasOrderedMemoryRef() || MIb.hasOrderedMemoryRef())
return false;
// Retrieve the base, offset from the base and width. Width
// is the size of memory that is being loaded/stored (e.g. 1, 2, 4, 8). If
// base are identical, and the offset of a lower memory access +
// the width doesn't overlap the offset of a higher memory access,
// then the memory accesses are different.
if (getMemOperandWithOffsetWidth(MIa, BaseOpA, OffsetA, WidthA, TRI) &&
getMemOperandWithOffsetWidth(MIb, BaseOpB, OffsetB, WidthB, TRI)) {
if (BaseOpA->isIdenticalTo(*BaseOpB)) {
int LowOffset = OffsetA < OffsetB ? OffsetA : OffsetB;
int HighOffset = OffsetA < OffsetB ? OffsetB : OffsetA;
int LowWidth = (LowOffset == OffsetA) ? WidthA : WidthB;
if (LowOffset + LowWidth <= HighOffset)
return true;
}
}
return false;
}
bool AArch64InstrInfo::isSchedulingBoundary(const MachineInstr &MI,
const MachineBasicBlock *MBB,
const MachineFunction &MF) const {
if (TargetInstrInfo::isSchedulingBoundary(MI, MBB, MF))
return true;
switch (MI.getOpcode()) {
case AArch64::HINT:
// CSDB hints are scheduling barriers.
if (MI.getOperand(0).getImm() == 0x14)
return true;
break;
case AArch64::DSB:
case AArch64::ISB:
// DSB and ISB also are scheduling barriers.
return true;
default:;
}
return isSEHInstruction(MI);
}
/// 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 AArch64InstrInfo::analyzeCompare(const MachineInstr &MI, unsigned &SrcReg,
unsigned &SrcReg2, int &CmpMask,
int &CmpValue) const {
// The first operand can be a frame index where we'd normally expect a
// register.
assert(MI.getNumOperands() >= 2 && "All AArch64 cmps should have 2 operands");
if (!MI.getOperand(1).isReg())
return false;
switch (MI.getOpcode()) {
default:
break;
case AArch64::SUBSWrr:
case AArch64::SUBSWrs:
case AArch64::SUBSWrx:
case AArch64::SUBSXrr:
case AArch64::SUBSXrs:
case AArch64::SUBSXrx:
case AArch64::ADDSWrr:
case AArch64::ADDSWrs:
case AArch64::ADDSWrx:
case AArch64::ADDSXrr:
case AArch64::ADDSXrs:
case AArch64::ADDSXrx:
// Replace SUBSWrr with SUBWrr if NZCV is not used.
SrcReg = MI.getOperand(1).getReg();
SrcReg2 = MI.getOperand(2).getReg();
CmpMask = ~0;
CmpValue = 0;
return true;
case AArch64::SUBSWri:
case AArch64::ADDSWri:
case AArch64::SUBSXri:
case AArch64::ADDSXri:
SrcReg = MI.getOperand(1).getReg();
SrcReg2 = 0;
CmpMask = ~0;
// FIXME: In order to convert CmpValue to 0 or 1
CmpValue = MI.getOperand(2).getImm() != 0;
return true;
case AArch64::ANDSWri:
case AArch64::ANDSXri:
// ANDS does not use the same encoding scheme as the others xxxS
// instructions.
SrcReg = MI.getOperand(1).getReg();
SrcReg2 = 0;
CmpMask = ~0;
// FIXME:The return val type of decodeLogicalImmediate is uint64_t,
// while the type of CmpValue is int. When converting uint64_t to int,
// the high 32 bits of uint64_t will be lost.
// In fact it causes a bug in spec2006-483.xalancbmk
// CmpValue is only used to compare with zero in OptimizeCompareInstr
CmpValue = AArch64_AM::decodeLogicalImmediate(
MI.getOperand(2).getImm(),
MI.getOpcode() == AArch64::ANDSWri ? 32 : 64) != 0;
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 TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
const TargetRegisterInfo *TRI = MF->getSubtarget().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!");
Register Reg = MO.getReg();
if (Register::isPhysicalRegister(Reg)) {
if (!OpRegCstraints->contains(Reg))
return false;
} else if (!OpRegCstraints->hasSubClassEq(MRI->getRegClass(Reg)) &&
!MRI->constrainRegClass(Reg, OpRegCstraints))
return false;
}
return true;
}
/// Return the opcode that does not set flags when possible - otherwise
/// return the original opcode. The caller is responsible to do the actual
/// substitution and legality checking.
static unsigned convertToNonFlagSettingOpc(const MachineInstr &MI) {
// Don't convert all compare instructions, because for some the zero register
// encoding becomes the sp register.
bool MIDefinesZeroReg = false;
if (MI.definesRegister(AArch64::WZR) || MI.definesRegister(AArch64::XZR))
MIDefinesZeroReg = true;
switch (MI.getOpcode()) {
default:
return MI.getOpcode();
case AArch64::ADDSWrr:
return AArch64::ADDWrr;
case AArch64::ADDSWri:
return MIDefinesZeroReg ? AArch64::ADDSWri : AArch64::ADDWri;
case AArch64::ADDSWrs:
return MIDefinesZeroReg ? AArch64::ADDSWrs : AArch64::ADDWrs;
case AArch64::ADDSWrx:
return AArch64::ADDWrx;
case AArch64::ADDSXrr:
return AArch64::ADDXrr;
case AArch64::ADDSXri:
return MIDefinesZeroReg ? AArch64::ADDSXri : AArch64::ADDXri;
case AArch64::ADDSXrs:
return MIDefinesZeroReg ? AArch64::ADDSXrs : AArch64::ADDXrs;
case AArch64::ADDSXrx:
return AArch64::ADDXrx;
case AArch64::SUBSWrr:
return AArch64::SUBWrr;
case AArch64::SUBSWri:
return MIDefinesZeroReg ? AArch64::SUBSWri : AArch64::SUBWri;
case AArch64::SUBSWrs:
return MIDefinesZeroReg ? AArch64::SUBSWrs : AArch64::SUBWrs;
case AArch64::SUBSWrx:
return AArch64::SUBWrx;
case AArch64::SUBSXrr:
return AArch64::SUBXrr;
case AArch64::SUBSXri:
return MIDefinesZeroReg ? AArch64::SUBSXri : AArch64::SUBXri;
case AArch64::SUBSXrs:
return MIDefinesZeroReg ? AArch64::SUBSXrs : AArch64::SUBXrs;
case AArch64::SUBSXrx:
return AArch64::SUBXrx;
}
}
enum AccessKind { AK_Write = 0x01, AK_Read = 0x10, AK_All = 0x11 };
/// True when condition flags are accessed (either by writing or reading)
/// on the instruction trace starting at From and ending at To.
///
/// Note: If From and To are from different blocks it's assumed CC are accessed
/// on the path.
static bool areCFlagsAccessedBetweenInstrs(
MachineBasicBlock::iterator From, MachineBasicBlock::iterator To,
const TargetRegisterInfo *TRI, const AccessKind AccessToCheck = AK_All) {
// Early exit if To is at the beginning of the BB.
if (To == To->getParent()->begin())
return true;
// Check whether the instructions are in the same basic block
// If not, assume the condition flags might get modified somewhere.
if (To->getParent() != From->getParent())
return true;
// From must be above To.
assert(std::find_if(++To.getReverse(), To->getParent()->rend(),
[From](MachineInstr &MI) {
return MI.getIterator() == From;
}) != To->getParent()->rend());
// We iterate backward starting \p To until we hit \p From.
for (--To; To != From; --To) {
const MachineInstr &Instr = *To;
if (((AccessToCheck & AK_Write) &&
Instr.modifiesRegister(AArch64::NZCV, TRI)) ||
((AccessToCheck & AK_Read) && Instr.readsRegister(AArch64::NZCV, TRI)))
return true;
}
return false;
}
/// Try to optimize a compare instruction. A compare instruction is an
/// instruction which produces AArch64::NZCV. It can be truly compare
/// instruction
/// when there are no uses of its destination register.
///
/// The following steps are tried in order:
/// 1. Convert CmpInstr into an unconditional version.
/// 2. Remove CmpInstr if above there is an instruction producing a needed
/// condition code or an instruction which can be converted into such an
/// instruction.
/// Only comparison with zero is supported.
bool AArch64InstrInfo::optimizeCompareInstr(
MachineInstr &CmpInstr, unsigned SrcReg, unsigned SrcReg2, int CmpMask,
int CmpValue, const MachineRegisterInfo *MRI) const {
assert(CmpInstr.getParent());
assert(MRI);
// Replace SUBSWrr with SUBWrr if NZCV is not used.
int DeadNZCVIdx = CmpInstr.findRegisterDefOperandIdx(AArch64::NZCV, true);
if (DeadNZCVIdx != -1) {
if (CmpInstr.definesRegister(AArch64::WZR) ||
CmpInstr.definesRegister(AArch64::XZR)) {
CmpInstr.eraseFromParent();
return true;
}
unsigned Opc = CmpInstr.getOpcode();
unsigned NewOpc = convertToNonFlagSettingOpc(CmpInstr);
if (NewOpc == Opc)
return false;
const MCInstrDesc &MCID = get(NewOpc);
CmpInstr.setDesc(MCID);
CmpInstr.RemoveOperand(DeadNZCVIdx);
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.
// FIXME:CmpValue has already been converted to 0 or 1 in analyzeCompare
// function.
assert((CmpValue == 0 || CmpValue == 1) && "CmpValue must be 0 or 1!");
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;
return substituteCmpToZero(CmpInstr, SrcReg, MRI);
}
/// Get opcode of S version of Instr.
/// If Instr is S version its opcode is returned.
/// AArch64::INSTRUCTION_LIST_END is returned if Instr does not have S version
/// or we are not interested in it.
static unsigned sForm(MachineInstr &Instr) {
switch (Instr.getOpcode()) {
default:
return AArch64::INSTRUCTION_LIST_END;
case AArch64::ADDSWrr:
case AArch64::ADDSWri:
case AArch64::ADDSXrr:
case AArch64::ADDSXri:
case AArch64::SUBSWrr:
case AArch64::SUBSWri:
case AArch64::SUBSXrr:
case AArch64::SUBSXri:
return Instr.getOpcode();
case AArch64::ADDWrr:
return AArch64::ADDSWrr;
case AArch64::ADDWri:
return AArch64::ADDSWri;
case AArch64::ADDXrr:
return AArch64::ADDSXrr;
case AArch64::ADDXri:
return AArch64::ADDSXri;
case AArch64::ADCWr:
return AArch64::ADCSWr;
case AArch64::ADCXr:
return AArch64::ADCSXr;
case AArch64::SUBWrr:
return AArch64::SUBSWrr;
case AArch64::SUBWri:
return AArch64::SUBSWri;
case AArch64::SUBXrr:
return AArch64::SUBSXrr;
case AArch64::SUBXri:
return AArch64::SUBSXri;
case AArch64::SBCWr:
return AArch64::SBCSWr;
case AArch64::SBCXr:
return AArch64::SBCSXr;
case AArch64::ANDWri:
return AArch64::ANDSWri;
case AArch64::ANDXri:
return AArch64::ANDSXri;
}
}
/// Check if AArch64::NZCV should be alive in successors of MBB.
static bool areCFlagsAliveInSuccessors(MachineBasicBlock *MBB) {
for (auto *BB : MBB->successors())
if (BB->isLiveIn(AArch64::NZCV))
return true;
return false;
}
namespace {
struct UsedNZCV {
bool N = false;
bool Z = false;
bool C = false;
bool V = false;
UsedNZCV() = default;
UsedNZCV &operator|=(const UsedNZCV &UsedFlags) {
this->N |= UsedFlags.N;
this->Z |= UsedFlags.Z;
this->C |= UsedFlags.C;
this->V |= UsedFlags.V;
return *this;
}
};
} // end anonymous namespace
/// Find a condition code used by the instruction.
/// Returns AArch64CC::Invalid if either the instruction does not use condition
/// codes or we don't optimize CmpInstr in the presence of such instructions.
static AArch64CC::CondCode findCondCodeUsedByInstr(const MachineInstr &Instr) {
switch (Instr.getOpcode()) {
default:
return AArch64CC::Invalid;
case AArch64::Bcc: {
int Idx = Instr.findRegisterUseOperandIdx(AArch64::NZCV);
assert(Idx >= 2);
return static_cast<AArch64CC::CondCode>(Instr.getOperand(Idx - 2).getImm());
}
case AArch64::CSINVWr:
case AArch64::CSINVXr:
case AArch64::CSINCWr:
case AArch64::CSINCXr:
case AArch64::CSELWr:
case AArch64::CSELXr:
case AArch64::CSNEGWr:
case AArch64::CSNEGXr:
case AArch64::FCSELSrrr:
case AArch64::FCSELDrrr: {
int Idx = Instr.findRegisterUseOperandIdx(AArch64::NZCV);
assert(Idx >= 1);
return static_cast<AArch64CC::CondCode>(Instr.getOperand(Idx - 1).getImm());
}
}
}
static UsedNZCV getUsedNZCV(AArch64CC::CondCode CC) {
assert(CC != AArch64CC::Invalid);
UsedNZCV UsedFlags;
switch (CC) {
default:
break;
case AArch64CC::EQ: // Z set
case AArch64CC::NE: // Z clear
UsedFlags.Z = true;
break;
case AArch64CC::HI: // Z clear and C set
case AArch64CC::LS: // Z set or C clear
UsedFlags.Z = true;
LLVM_FALLTHROUGH;
case AArch64CC::HS: // C set
case AArch64CC::LO: // C clear
UsedFlags.C = true;
break;
case AArch64CC::MI: // N set
case AArch64CC::PL: // N clear
UsedFlags.N = true;
break;
case AArch64CC::VS: // V set
case AArch64CC::VC: // V clear
UsedFlags.V = true;
break;
case AArch64CC::GT: // Z clear, N and V the same
case AArch64CC::LE: // Z set, N and V differ
UsedFlags.Z = true;
LLVM_FALLTHROUGH;
case AArch64CC::GE: // N and V the same
case AArch64CC::LT: // N and V differ
UsedFlags.N = true;
UsedFlags.V = true;
break;
}
return UsedFlags;
}
static bool isADDSRegImm(unsigned Opcode) {
return Opcode == AArch64::ADDSWri || Opcode == AArch64::ADDSXri;
}
static bool isSUBSRegImm(unsigned Opcode) {
return Opcode == AArch64::SUBSWri || Opcode == AArch64::SUBSXri;
}
/// Check if CmpInstr can be substituted by MI.
///
/// CmpInstr can be substituted:
/// - CmpInstr is either 'ADDS %vreg, 0' or 'SUBS %vreg, 0'
/// - and, MI and CmpInstr are from the same MachineBB
/// - and, condition flags are not alive in successors of the CmpInstr parent
/// - and, if MI opcode is the S form there must be no defs of flags between
/// MI and CmpInstr
/// or if MI opcode is not the S form there must be neither defs of flags
/// nor uses of flags between MI and CmpInstr.
/// - and C/V flags are not used after CmpInstr
static bool canInstrSubstituteCmpInstr(MachineInstr *MI, MachineInstr *CmpInstr,
const TargetRegisterInfo *TRI) {
assert(MI);
assert(sForm(*MI) != AArch64::INSTRUCTION_LIST_END);
assert(CmpInstr);
const unsigned CmpOpcode = CmpInstr->getOpcode();
if (!isADDSRegImm(CmpOpcode) && !isSUBSRegImm(CmpOpcode))
return false;
if (MI->getParent() != CmpInstr->getParent())
return false;
if (areCFlagsAliveInSuccessors(CmpInstr->getParent()))
return false;
AccessKind AccessToCheck = AK_Write;
if (sForm(*MI) != MI->getOpcode())
AccessToCheck = AK_All;
if (areCFlagsAccessedBetweenInstrs(MI, CmpInstr, TRI, AccessToCheck))
return false;
UsedNZCV NZCVUsedAfterCmp;
for (auto I = std::next(CmpInstr->getIterator()),
E = CmpInstr->getParent()->instr_end();
I != E; ++I) {
const MachineInstr &Instr = *I;
if (Instr.readsRegister(AArch64::NZCV, TRI)) {
AArch64CC::CondCode CC = findCondCodeUsedByInstr(Instr);
if (CC == AArch64CC::Invalid) // Unsupported conditional instruction
return false;
NZCVUsedAfterCmp |= getUsedNZCV(CC);
}
if (Instr.modifiesRegister(AArch64::NZCV, TRI))
break;
}
return !NZCVUsedAfterCmp.C && !NZCVUsedAfterCmp.V;
}
/// Substitute an instruction comparing to zero with another instruction
/// which produces needed condition flags.
///
/// Return true on success.
bool AArch64InstrInfo::substituteCmpToZero(
MachineInstr &CmpInstr, unsigned SrcReg,
const MachineRegisterInfo *MRI) const {
assert(MRI);
// Get the unique definition of SrcReg.
MachineInstr *MI = MRI->getUniqueVRegDef(SrcReg);
if (!MI)
return false;
const TargetRegisterInfo *TRI = &getRegisterInfo();
unsigned NewOpc = sForm(*MI);
if (NewOpc == AArch64::INSTRUCTION_LIST_END)
return false;
if (!canInstrSubstituteCmpInstr(MI, &CmpInstr, TRI))
return false;
// Update the instruction to set NZCV.
MI->setDesc(get(NewOpc));
CmpInstr.eraseFromParent();
bool succeeded = UpdateOperandRegClass(*MI);
(void)succeeded;
assert(succeeded && "Some operands reg class are incompatible!");
MI->addRegisterDefined(AArch64::NZCV, TRI);
return true;
}
bool AArch64InstrInfo::expandPostRAPseudo(MachineInstr &MI) const {
if (MI.getOpcode() != TargetOpcode::LOAD_STACK_GUARD &&
MI.getOpcode() != AArch64::CATCHRET)
return false;
MachineBasicBlock &MBB = *MI.getParent();
auto &Subtarget = MBB.getParent()->getSubtarget<AArch64Subtarget>();
auto TRI = Subtarget.getRegisterInfo();
DebugLoc DL = MI.getDebugLoc();
if (MI.getOpcode() == AArch64::CATCHRET) {
// Skip to the first instruction before the epilog.
const TargetInstrInfo *TII =
MBB.getParent()->getSubtarget().getInstrInfo();
MachineBasicBlock *TargetMBB = MI.getOperand(0).getMBB();
auto MBBI = MachineBasicBlock::iterator(MI);
MachineBasicBlock::iterator FirstEpilogSEH = std::prev(MBBI);
while (FirstEpilogSEH->getFlag(MachineInstr::FrameDestroy) &&
FirstEpilogSEH != MBB.begin())
FirstEpilogSEH = std::prev(FirstEpilogSEH);
if (FirstEpilogSEH != MBB.begin())
FirstEpilogSEH = std::next(FirstEpilogSEH);
BuildMI(MBB, FirstEpilogSEH, DL, TII->get(AArch64::ADRP))
.addReg(AArch64::X0, RegState::Define)
.addMBB(TargetMBB);
BuildMI(MBB, FirstEpilogSEH, DL, TII->get(AArch64::ADDXri))
.addReg(AArch64::X0, RegState::Define)
.addReg(AArch64::X0)
.addMBB(TargetMBB)
.addImm(0);
return true;
}
Register Reg = MI.getOperand(0).getReg();
const GlobalValue *GV =
cast<GlobalValue>((*MI.memoperands_begin())->getValue());
const TargetMachine &TM = MBB.getParent()->getTarget();
unsigned OpFlags = Subtarget.ClassifyGlobalReference(GV, TM);
const unsigned char MO_NC = AArch64II::MO_NC;
if ((OpFlags & AArch64II::MO_GOT) != 0) {
BuildMI(MBB, MI, DL, get(AArch64::LOADgot), Reg)
.addGlobalAddress(GV, 0, OpFlags);
if (Subtarget.isTargetILP32()) {
unsigned Reg32 = TRI->getSubReg(Reg, AArch64::sub_32);
BuildMI(MBB, MI, DL, get(AArch64::LDRWui))
.addDef(Reg32, RegState::Dead)
.addUse(Reg, RegState::Kill)
.addImm(0)
.addMemOperand(*MI.memoperands_begin())
.addDef(Reg, RegState::Implicit);
} else {
BuildMI(MBB, MI, DL, get(AArch64::LDRXui), Reg)
.addReg(Reg, RegState::Kill)
.addImm(0)
.addMemOperand(*MI.memoperands_begin());
}
} else if (TM.getCodeModel() == CodeModel::Large) {
assert(!Subtarget.isTargetILP32() && "how can large exist in ILP32?");
BuildMI(MBB, MI, DL, get(AArch64::MOVZXi), Reg)
.addGlobalAddress(GV, 0, AArch64II::MO_G0 | MO_NC)
.addImm(0);
BuildMI(MBB, MI, DL, get(AArch64::MOVKXi), Reg)
.addReg(Reg, RegState::Kill)
.addGlobalAddress(GV, 0, AArch64II::MO_G1 | MO_NC)
.addImm(16);
BuildMI(MBB, MI, DL, get(AArch64::MOVKXi), Reg)
.addReg(Reg, RegState::Kill)
.addGlobalAddress(GV, 0, AArch64II::MO_G2 | MO_NC)
.addImm(32);
BuildMI(MBB, MI, DL, get(AArch64::MOVKXi), Reg)
.addReg(Reg, RegState::Kill)
.addGlobalAddress(GV, 0, AArch64II::MO_G3)
.addImm(48);
BuildMI(MBB, MI, DL, get(AArch64::LDRXui), Reg)
.addReg(Reg, RegState::Kill)
.addImm(0)
.addMemOperand(*MI.memoperands_begin());
} else if (TM.getCodeModel() == CodeModel::Tiny) {
BuildMI(MBB, MI, DL, get(AArch64::ADR), Reg)
.addGlobalAddress(GV, 0, OpFlags);
} else {
BuildMI(MBB, MI, DL, get(AArch64::ADRP), Reg)
.addGlobalAddress(GV, 0, OpFlags | AArch64II::MO_PAGE);
unsigned char LoFlags = OpFlags | AArch64II::MO_PAGEOFF | MO_NC;
if (Subtarget.isTargetILP32()) {
unsigned Reg32 = TRI->getSubReg(Reg, AArch64::sub_32);
BuildMI(MBB, MI, DL, get(AArch64::LDRWui))
.addDef(Reg32, RegState::Dead)
.addUse(Reg, RegState::Kill)
.addGlobalAddress(GV, 0, LoFlags)
.addMemOperand(*MI.memoperands_begin())
.addDef(Reg, RegState::Implicit);
} else {
BuildMI(MBB, MI, DL, get(AArch64::LDRXui), Reg)
.addReg(Reg, RegState::Kill)
.addGlobalAddress(GV, 0, LoFlags)
.addMemOperand(*MI.memoperands_begin());
}
}
MBB.erase(MI);
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 AArch64InstrInfo::isGPRZero(const MachineInstr &MI) {
switch (MI.getOpcode()) {
default:
break;
case AArch64::MOVZWi:
case AArch64::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 AArch64::ANDWri: // and Rd, Rzr, #imm
return MI.getOperand(1).getReg() == AArch64::WZR;
case AArch64::ANDXri:
return MI.getOperand(1).getReg() == AArch64::XZR;
case TargetOpcode::COPY:
return MI.getOperand(1).getReg() == AArch64::WZR;
}
return false;
}
// Return true if this instruction simply renames a general register without
// modifying bits.
bool AArch64InstrInfo::isGPRCopy(const MachineInstr &MI) {
switch (MI.getOpcode()) {
default:
break;
case TargetOpcode::COPY: {
// GPR32 copies will by lowered to ORRXrs
Register DstReg = MI.getOperand(0).getReg();
return (AArch64::GPR32RegClass.contains(DstReg) ||
AArch64::GPR64RegClass.contains(DstReg));
}
case AArch64::ORRXrs: // orr Xd, Xzr, Xm (LSL #0)
if (MI.getOperand(1).getReg() == AArch64::XZR) {
assert(MI.getDesc().getNumOperands() == 4 &&
MI.getOperand(3).getImm() == 0 && "invalid ORRrs operands");
return true;
}
break;
case AArch64::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;
}
break;
}
return false;
}
// Return true if this instruction simply renames a general register without
// modifying bits.
bool AArch64InstrInfo::isFPRCopy(const MachineInstr &MI) {
switch (MI.getOpcode()) {
default:
break;
case TargetOpcode::COPY: {
// FPR64 copies will by lowered to ORR.16b
Register DstReg = MI.getOperand(0).getReg();
return (AArch64::FPR64RegClass.contains(DstReg) ||
AArch64::FPR128RegClass.contains(DstReg));
}
case AArch64::ORRv16i8:
if (MI.getOperand(1).getReg() == MI.getOperand(2).getReg()) {
assert(MI.getDesc().getNumOperands() == 3 && MI.getOperand(0).isReg() &&
"invalid ORRv16i8 operands");
return true;
}
break;
}
return false;
}
unsigned AArch64InstrInfo::isLoadFromStackSlot(const MachineInstr &MI,
int &FrameIndex) const {
switch (MI.getOpcode()) {
default:
break;
case AArch64::LDRWui:
case AArch64::LDRXui:
case AArch64::LDRBui:
case AArch64::LDRHui:
case AArch64::LDRSui:
case AArch64::LDRDui:
case AArch64::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 AArch64InstrInfo::isStoreToStackSlot(const MachineInstr &MI,
int &FrameIndex) const {
switch (MI.getOpcode()) {
default:
break;
case AArch64::STRWui:
case AArch64::STRXui:
case AArch64::STRBui:
case AArch64::STRHui:
case AArch64::STRSui:
case AArch64::STRDui:
case AArch64::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;
}
/// Check all MachineMemOperands for a hint to suppress pairing.
bool AArch64InstrInfo::isLdStPairSuppressed(const MachineInstr &MI) {
return llvm::any_of(MI.memoperands(), [](MachineMemOperand *MMO) {
return MMO->getFlags() & MOSuppressPair;
});
}
/// Set a flag on the first MachineMemOperand to suppress pairing.
void AArch64InstrInfo::suppressLdStPair(MachineInstr &MI) {
if (MI.memoperands_empty())
return;
(*MI.memoperands_begin())->setFlags(MOSuppressPair);
}
/// Check all MachineMemOperands for a hint that the load/store is strided.
bool AArch64InstrInfo::isStridedAccess(const MachineInstr &MI) {
return llvm::any_of(MI.memoperands(), [](MachineMemOperand *MMO) {
return MMO->getFlags() & MOStridedAccess;
});
}
bool AArch64InstrInfo::isUnscaledLdSt(unsigned Opc) {
switch (Opc) {
default:
return false;
case AArch64::STURSi:
case AArch64::STURDi:
case AArch64::STURQi:
case AArch64::STURBBi:
case AArch64::STURHHi:
case AArch64::STURWi:
case AArch64::STURXi:
case AArch64::LDURSi:
case AArch64::LDURDi:
case AArch64::LDURQi:
case AArch64::LDURWi:
case AArch64::LDURXi:
case AArch64::LDURSWi:
case AArch64::LDURHHi:
case AArch64::LDURBBi:
case AArch64::LDURSBWi:
case AArch64::LDURSHWi:
return true;
}
}
Optional<unsigned> AArch64InstrInfo::getUnscaledLdSt(unsigned Opc) {
switch (Opc) {
default: return {};
case AArch64::PRFMui: return AArch64::PRFUMi;
case AArch64::LDRXui: return AArch64::LDURXi;
case AArch64::LDRWui: return AArch64::LDURWi;
case AArch64::LDRBui: return AArch64::LDURBi;
case AArch64::LDRHui: return AArch64::LDURHi;
case AArch64::LDRSui: return AArch64::LDURSi;
case AArch64::LDRDui: return AArch64::LDURDi;
case AArch64::LDRQui: return AArch64::LDURQi;
case AArch64::LDRBBui: return AArch64::LDURBBi;
case AArch64::LDRHHui: return AArch64::LDURHHi;
case AArch64::LDRSBXui: return AArch64::LDURSBXi;
case AArch64::LDRSBWui: return AArch64::LDURSBWi;
case AArch64::LDRSHXui: return AArch64::LDURSHXi;
case AArch64::LDRSHWui: return AArch64::LDURSHWi;
case AArch64::LDRSWui: return AArch64::LDURSWi;
case AArch64::STRXui: return AArch64::STURXi;
case AArch64::STRWui: return AArch64::STURWi;
case AArch64::STRBui: return AArch64::STURBi;
case AArch64::STRHui: return AArch64::STURHi;
case AArch64::STRSui: return AArch64::STURSi;
case AArch64::STRDui: return AArch64::STURDi;
case AArch64::STRQui: return AArch64::STURQi;
case AArch64::STRBBui: return AArch64::STURBBi;
case AArch64::STRHHui: return AArch64::STURHHi;
}
}
unsigned AArch64InstrInfo::getLoadStoreImmIdx(unsigned Opc) {
switch (Opc) {
default:
return 2;
case AArch64::LDPXi:
case AArch64::LDPDi:
case AArch64::STPXi:
case AArch64::STPDi:
case AArch64::LDNPXi:
case AArch64::LDNPDi:
case AArch64::STNPXi:
case AArch64::STNPDi:
case AArch64::LDPQi:
case AArch64::STPQi:
case AArch64::LDNPQi:
case AArch64::STNPQi:
case AArch64::LDPWi:
case AArch64::LDPSi:
case AArch64::STPWi:
case AArch64::STPSi:
case AArch64::LDNPWi:
case AArch64::LDNPSi:
case AArch64::STNPWi:
case AArch64::STNPSi:
case AArch64::LDG:
case AArch64::STGPi:
return 3;
case AArch64::ADDG:
case AArch64::STGOffset:
return 2;
}
}
bool AArch64InstrInfo::isPairableLdStInst(const MachineInstr &MI) {
switch (MI.getOpcode()) {
default:
return false;
// Scaled instructions.
case AArch64::STRSui:
case AArch64::STRDui:
case AArch64::STRQui:
case AArch64::STRXui:
case AArch64::STRWui:
case AArch64::LDRSui:
case AArch64::LDRDui:
case AArch64::LDRQui:
case AArch64::LDRXui:
case AArch64::LDRWui:
case AArch64::LDRSWui:
// Unscaled instructions.
case AArch64::STURSi:
case AArch64::STURDi:
case AArch64::STURQi:
case AArch64::STURWi:
case AArch64::STURXi:
case AArch64::LDURSi:
case AArch64::LDURDi:
case AArch64::LDURQi:
case AArch64::LDURWi:
case AArch64::LDURXi:
case AArch64::LDURSWi:
return true;
}
}
unsigned AArch64InstrInfo::convertToFlagSettingOpc(unsigned Opc,
bool &Is64Bit) {
switch (Opc) {
default:
llvm_unreachable("Opcode has no flag setting equivalent!");
// 32-bit cases:
case AArch64::ADDWri:
Is64Bit = false;
return AArch64::ADDSWri;
case AArch64::ADDWrr:
Is64Bit = false;
return AArch64::ADDSWrr;
case AArch64::ADDWrs:
Is64Bit = false;
return AArch64::ADDSWrs;
case AArch64::ADDWrx:
Is64Bit = false;
return AArch64::ADDSWrx;
case AArch64::ANDWri:
Is64Bit = false;
return AArch64::ANDSWri;
case AArch64::ANDWrr:
Is64Bit = false;
return AArch64::ANDSWrr;
case AArch64::ANDWrs:
Is64Bit = false;
return AArch64::ANDSWrs;
case AArch64::BICWrr:
Is64Bit = false;
return AArch64::BICSWrr;
case AArch64::BICWrs:
Is64Bit = false;
return AArch64::BICSWrs;
case AArch64::SUBWri:
Is64Bit = false;
return AArch64::SUBSWri;
case AArch64::SUBWrr:
Is64Bit = false;
return AArch64::SUBSWrr;
case AArch64::SUBWrs:
Is64Bit = false;
return AArch64::SUBSWrs;
case AArch64::SUBWrx:
Is64Bit = false;
return AArch64::SUBSWrx;
// 64-bit cases:
case AArch64::ADDXri:
Is64Bit = true;
return AArch64::ADDSXri;
case AArch64::ADDXrr:
Is64Bit = true;
return AArch64::ADDSXrr;
case AArch64::ADDXrs:
Is64Bit = true;
return AArch64::ADDSXrs;
case AArch64::ADDXrx:
Is64Bit = true;
return AArch64::ADDSXrx;
case AArch64::ANDXri:
Is64Bit = true;
return AArch64::ANDSXri;
case AArch64::ANDXrr:
Is64Bit = true;
return AArch64::ANDSXrr;
case AArch64::ANDXrs:
Is64Bit = true;
return AArch64::ANDSXrs;
case AArch64::BICXrr:
Is64Bit = true;
return AArch64::BICSXrr;
case AArch64::BICXrs:
Is64Bit = true;
return AArch64::BICSXrs;
case AArch64::SUBXri:
Is64Bit = true;
return AArch64::SUBSXri;
case AArch64::SUBXrr:
Is64Bit = true;
return AArch64::SUBSXrr;
case AArch64::SUBXrs:
Is64Bit = true;
return AArch64::SUBSXrs;
case AArch64::SUBXrx:
Is64Bit = true;
return AArch64::SUBSXrx;
}
}
// Is this a candidate for ld/st merging or pairing? For example, we don't
// touch volatiles or load/stores that have a hint to avoid pair formation.
bool AArch64InstrInfo::isCandidateToMergeOrPair(const MachineInstr &MI) const {
// If this is a volatile load/store, don't mess with it.
if (MI.hasOrderedMemoryRef())
return false;
// Make sure this is a reg/fi+imm (as opposed to an address reloc).
assert((MI.getOperand(1).isReg() || MI.getOperand(1).isFI()) &&
"Expected a reg or frame index operand.");
if (!MI.getOperand(2).isImm())
return false;
// Can't merge/pair if the instruction modifies the base register.
// e.g., ldr x0, [x0]
// This case will never occur with an FI base.
if (MI.getOperand(1).isReg()) {
Register BaseReg = MI.getOperand(1).getReg();
const TargetRegisterInfo *TRI = &getRegisterInfo();
if (MI.modifiesRegister(BaseReg, TRI))
return false;
}
// Check if this load/store has a hint to avoid pair formation.
// MachineMemOperands hints are set by the AArch64StorePairSuppress pass.
if (isLdStPairSuppressed(MI))
return false;
// Do not pair any callee-save store/reload instructions in the
// prologue/epilogue if the CFI information encoded the operations as separate
// instructions, as that will cause the size of the actual prologue to mismatch
// with the prologue size recorded in the Windows CFI.
const MCAsmInfo *MAI = MI.getMF()->getTarget().getMCAsmInfo();
bool NeedsWinCFI = MAI->usesWindowsCFI() &&
MI.getMF()->getFunction().needsUnwindTableEntry();
if (NeedsWinCFI && (MI.getFlag(MachineInstr::FrameSetup) ||
MI.getFlag(MachineInstr::FrameDestroy)))
return false;
// On some CPUs quad load/store pairs are slower than two single load/stores.
if (Subtarget.isPaired128Slow()) {
switch (MI.getOpcode()) {
default:
break;
case AArch64::LDURQi:
case AArch64::STURQi:
case AArch64::LDRQui:
case AArch64::STRQui:
return false;
}
}
return true;
}
bool AArch64InstrInfo::getMemOperandWithOffset(const MachineInstr &LdSt,
const MachineOperand *&BaseOp,
int64_t &Offset,
const TargetRegisterInfo *TRI) const {
if (!LdSt.mayLoadOrStore())
return false;
unsigned Width;
return getMemOperandWithOffsetWidth(LdSt, BaseOp, Offset, Width, TRI);
}
bool AArch64InstrInfo::getMemOperandWithOffsetWidth(
const MachineInstr &LdSt, const MachineOperand *&BaseOp, int64_t &Offset,
unsigned &Width, const TargetRegisterInfo *TRI) const {
assert(LdSt.mayLoadOrStore() && "Expected a memory operation.");
// Handle only loads/stores with base register followed by immediate offset.
if (LdSt.getNumExplicitOperands() == 3) {
// Non-paired instruction (e.g., ldr x1, [x0, #8]).
if ((!LdSt.getOperand(1).isReg() && !LdSt.getOperand(1).isFI()) ||
!LdSt.getOperand(2).isImm())
return false;
} else if (LdSt.getNumExplicitOperands() == 4) {
// Paired instruction (e.g., ldp x1, x2, [x0, #8]).
if (!LdSt.getOperand(1).isReg() ||
(!LdSt.getOperand(2).isReg() && !LdSt.getOperand(2).isFI()) ||
!LdSt.getOperand(3).isImm())
return false;
} else
return false;
// Get the scaling factor for the instruction and set the width for the
// instruction.
unsigned Scale = 0;
int64_t Dummy1, Dummy2;
// If this returns false, then it's an instruction we don't want to handle.
if (!getMemOpInfo(LdSt.getOpcode(), Scale, Width, Dummy1, Dummy2))
return false;
// Compute the offset. Offset is calculated as the immediate operand
// multiplied by the scaling factor. Unscaled instructions have scaling factor
// set to 1.
if (LdSt.getNumExplicitOperands() == 3) {
BaseOp = &LdSt.getOperand(1);
Offset = LdSt.getOperand(2).getImm() * Scale;
} else {
assert(LdSt.getNumExplicitOperands() == 4 && "invalid number of operands");
BaseOp = &LdSt.getOperand(2);
Offset = LdSt.getOperand(3).getImm() * Scale;
}
if (!BaseOp->isReg() && !BaseOp->isFI())
return false;
return true;
}
MachineOperand &
AArch64InstrInfo::getMemOpBaseRegImmOfsOffsetOperand(MachineInstr &LdSt) const {
assert(LdSt.mayLoadOrStore() && "Expected a memory operation.");
MachineOperand &OfsOp = LdSt.getOperand(LdSt.getNumExplicitOperands() - 1);
assert(OfsOp.isImm() && "Offset operand wasn't immediate.");
return OfsOp;
}
bool AArch64InstrInfo::getMemOpInfo(unsigned Opcode, unsigned &Scale,
unsigned &Width, int64_t &MinOffset,
int64_t &MaxOffset) {
switch (Opcode) {
// Not a memory operation or something we want to handle.
default:
Scale = Width = 0;
MinOffset = MaxOffset = 0;
return false;
case AArch64::STRWpost:
case AArch64::LDRWpost:
Width = 32;
Scale = 4;
MinOffset = -256;
MaxOffset = 255;
break;
case AArch64::LDURQi:
case AArch64::STURQi:
Width = 16;
Scale = 1;
MinOffset = -256;
MaxOffset = 255;
break;
case AArch64::PRFUMi:
case AArch64::LDURXi:
case AArch64::LDURDi:
case AArch64::STURXi:
case AArch64::STURDi:
Width = 8;
Scale = 1;
MinOffset = -256;
MaxOffset = 255;
break;
case AArch64::LDURWi:
case AArch64::LDURSi:
case AArch64::LDURSWi:
case AArch64::STURWi:
case AArch64::STURSi:
Width = 4;
Scale = 1;
MinOffset = -256;
MaxOffset = 255;
break;
case AArch64::LDURHi:
case AArch64::LDURHHi:
case AArch64::LDURSHXi:
case AArch64::LDURSHWi:
case AArch64::STURHi:
case AArch64::STURHHi:
Width = 2;
Scale = 1;
MinOffset = -256;
MaxOffset = 255;
break;
case AArch64::LDURBi:
case AArch64::LDURBBi:
case AArch64::LDURSBXi:
case AArch64::LDURSBWi:
case AArch64::STURBi:
case AArch64::STURBBi:
Width = 1;
Scale = 1;
MinOffset = -256;
MaxOffset = 255;
break;
case AArch64::LDPQi:
case AArch64::LDNPQi:
case AArch64::STPQi:
case AArch64::STNPQi:
Scale = 16;
Width = 32;
MinOffset = -64;
MaxOffset = 63;
break;
case AArch64::LDRQui:
case AArch64::STRQui:
Scale = Width = 16;
MinOffset = 0;
MaxOffset = 4095;
break;
case AArch64::LDPXi:
case AArch64::LDPDi:
case AArch64::LDNPXi:
case AArch64::LDNPDi:
case AArch64::STPXi:
case AArch64::STPDi:
case AArch64::STNPXi:
case AArch64::STNPDi:
Scale = 8;
Width = 16;
MinOffset = -64;
MaxOffset = 63;
break;
case AArch64::PRFMui:
case AArch64::LDRXui:
case AArch64::LDRDui:
case AArch64::STRXui:
case AArch64::STRDui:
Scale = Width = 8;
MinOffset = 0;
MaxOffset = 4095;
break;
case AArch64::LDPWi:
case AArch64::LDPSi:
case AArch64::LDNPWi:
case AArch64::LDNPSi:
case AArch64::STPWi:
case AArch64::STPSi:
case AArch64::STNPWi:
case AArch64::STNPSi:
Scale = 4;
Width = 8;
MinOffset = -64;
MaxOffset = 63;
break;
case AArch64::LDRWui:
case AArch64::LDRSui:
case AArch64::LDRSWui:
case AArch64::STRWui:
case AArch64::STRSui:
Scale = Width = 4;
MinOffset = 0;
MaxOffset = 4095;
break;
case AArch64::LDRHui:
case AArch64::LDRHHui:
case AArch64::LDRSHWui:
case AArch64::LDRSHXui:
case AArch64::STRHui:
case AArch64::STRHHui:
Scale = Width = 2;
MinOffset = 0;
MaxOffset = 4095;
break;
case AArch64::LDRBui:
case AArch64::LDRBBui:
case AArch64::LDRSBWui:
case AArch64::LDRSBXui:
case AArch64::STRBui:
case AArch64::STRBBui:
Scale = Width = 1;
MinOffset = 0;
MaxOffset = 4095;
break;
case AArch64::ADDG:
Scale = 16;
Width = 0;
MinOffset = 0;
MaxOffset = 63;
break;
case AArch64::TAGPstack:
Scale = 16;
Width = 0;
// TAGP with a negative offset turns into SUBP, which has a maximum offset
// of 63 (not 64!).
MinOffset = -63;
MaxOffset = 63;
break;
case AArch64::LDG:
case AArch64::STGOffset:
case AArch64::STZGOffset:
Scale = Width = 16;
MinOffset = -256;
MaxOffset = 255;
break;
case AArch64::LDR_PXI:
case AArch64::STR_PXI:
Scale = Width = 2;
MinOffset = -256;
MaxOffset = 255;
break;
case AArch64::LDR_ZXI:
case AArch64::STR_ZXI:
Scale = Width = 16;
MinOffset = -256;
MaxOffset = 255;
break;
case AArch64::ST2GOffset:
case AArch64::STZ2GOffset:
Scale = 16;
Width = 32;
MinOffset = -256;
MaxOffset = 255;
break;
case AArch64::STGPi:
Scale = Width = 16;
MinOffset = -64;
MaxOffset = 63;
break;
}
return true;
}
// Scaling factor for unscaled load or store.
int AArch64InstrInfo::getMemScale(unsigned Opc) {
switch (Opc) {
default:
llvm_unreachable("Opcode has unknown scale!");
case AArch64::LDRBBui:
case AArch64::LDURBBi:
case AArch64::LDRSBWui:
case AArch64::LDURSBWi:
case AArch64::STRBBui:
case AArch64::STURBBi:
return 1;
case AArch64::LDRHHui:
case AArch64::LDURHHi:
case AArch64::LDRSHWui:
case AArch64::LDURSHWi:
case AArch64::STRHHui:
case AArch64::STURHHi:
return 2;
case AArch64::LDRSui:
case AArch64::LDURSi:
case AArch64::LDRSWui:
case AArch64::LDURSWi:
case AArch64::LDRWui:
case AArch64::LDURWi:
case AArch64::STRSui:
case AArch64::STURSi:
case AArch64::STRWui:
case AArch64::STURWi:
case AArch64::LDPSi:
case AArch64::LDPSWi:
case AArch64::LDPWi:
case AArch64::STPSi:
case AArch64::STPWi:
return 4;
case AArch64::LDRDui:
case AArch64::LDURDi:
case AArch64::LDRXui:
case AArch64::LDURXi:
case AArch64::STRDui:
case AArch64::STURDi:
case AArch64::STRXui:
case AArch64::STURXi:
case AArch64::LDPDi:
case AArch64::LDPXi:
case AArch64::STPDi:
case AArch64::STPXi:
return 8;
case AArch64::LDRQui:
case AArch64::LDURQi:
case AArch64::STRQui:
case AArch64::STURQi:
case AArch64::LDPQi:
case AArch64::STPQi:
case AArch64::STGOffset:
case AArch64::STZGOffset:
case AArch64::ST2GOffset:
case AArch64::STZ2GOffset:
case AArch64::STGPi:
return 16;
}
}
// Scale the unscaled offsets. Returns false if the unscaled offset can't be
// scaled.
static bool scaleOffset(unsigned Opc, int64_t &Offset) {
int Scale = AArch64InstrInfo::getMemScale(Opc);
// If the byte-offset isn't a multiple of the stride, we can't scale this
// offset.
if (Offset % Scale != 0)
return false;
// Convert the byte-offset used by unscaled into an "element" offset used
// by the scaled pair load/store instructions.
Offset /= Scale;
return true;
}
static bool canPairLdStOpc(unsigned FirstOpc, unsigned SecondOpc) {
if (FirstOpc == SecondOpc)
return true;
// We can also pair sign-ext and zero-ext instructions.
switch (FirstOpc) {
default:
return false;
case AArch64::LDRWui:
case AArch64::LDURWi:
return SecondOpc == AArch64::LDRSWui || SecondOpc == AArch64::LDURSWi;
case AArch64::LDRSWui:
case AArch64::LDURSWi:
return SecondOpc == AArch64::LDRWui || SecondOpc == AArch64::LDURWi;
}
// These instructions can't be paired based on their opcodes.
return false;
}
static bool shouldClusterFI(const MachineFrameInfo &MFI, int FI1,
int64_t Offset1, unsigned Opcode1, int FI2,
int64_t Offset2, unsigned Opcode2) {
// Accesses through fixed stack object frame indices may access a different
// fixed stack slot. Check that the object offsets + offsets match.
if (MFI.isFixedObjectIndex(FI1) && MFI.isFixedObjectIndex(FI2)) {
int64_t ObjectOffset1 = MFI.getObjectOffset(FI1);
int64_t ObjectOffset2 = MFI.getObjectOffset(FI2);
assert(ObjectOffset1 <= ObjectOffset2 && "Object offsets are not ordered.");
// Convert to scaled object offsets.
int Scale1 = AArch64InstrInfo::getMemScale(Opcode1);
if (ObjectOffset1 % Scale1 != 0)
return false;
ObjectOffset1 /= Scale1;
int Scale2 = AArch64InstrInfo::getMemScale(Opcode2);
if (ObjectOffset2 % Scale2 != 0)
return false;
ObjectOffset2 /= Scale2;
ObjectOffset1 += Offset1;
ObjectOffset2 += Offset2;
return ObjectOffset1 + 1 == ObjectOffset2;
}
return FI1 == FI2;
}
/// Detect opportunities for ldp/stp formation.
///
/// Only called for LdSt for which getMemOperandWithOffset returns true.
bool AArch64InstrInfo::shouldClusterMemOps(const MachineOperand &BaseOp1,
const MachineOperand &BaseOp2,
unsigned NumLoads) const {
const MachineInstr &FirstLdSt = *BaseOp1.getParent();
const MachineInstr &SecondLdSt = *BaseOp2.getParent();
if (BaseOp1.getType() != BaseOp2.getType())
return false;
assert((BaseOp1.isReg() || BaseOp1.isFI()) &&
"Only base registers and frame indices are supported.");
// Check for both base regs and base FI.
if (BaseOp1.isReg() && BaseOp1.getReg() != BaseOp2.getReg())
return false;
// Only cluster up to a single pair.
if (NumLoads > 1)
return false;
if (!isPairableLdStInst(FirstLdSt) || !isPairableLdStInst(SecondLdSt))
return false;
// Can we pair these instructions based on their opcodes?
unsigned FirstOpc = FirstLdSt.getOpcode();
unsigned SecondOpc = SecondLdSt.getOpcode();
if (!canPairLdStOpc(FirstOpc, SecondOpc))
return false;
// Can't merge volatiles or load/stores that have a hint to avoid pair
// formation, for example.
if (!isCandidateToMergeOrPair(FirstLdSt) ||
!isCandidateToMergeOrPair(SecondLdSt))
return false;
// isCandidateToMergeOrPair guarantees that operand 2 is an immediate.
int64_t Offset1 = FirstLdSt.getOperand(2).getImm();
if (isUnscaledLdSt(FirstOpc) && !scaleOffset(FirstOpc, Offset1))
return false;
int64_t Offset2 = SecondLdSt.getOperand(2).getImm();
if (isUnscaledLdSt(SecondOpc) && !scaleOffset(SecondOpc, Offset2))
return false;
// Pairwise instructions have a 7-bit signed offset field.
if (Offset1 > 63 || Offset1 < -64)
return false;
// The caller should already have ordered First/SecondLdSt by offset.
// Note: except for non-equal frame index bases
if (BaseOp1.isFI()) {
assert((!BaseOp1.isIdenticalTo(BaseOp2) || Offset1 <= Offset2) &&
"Caller should have ordered offsets.");
const MachineFrameInfo &MFI =
FirstLdSt.getParent()->getParent()->getFrameInfo();
return shouldClusterFI(MFI, BaseOp1.getIndex(), Offset1, FirstOpc,
BaseOp2.getIndex(), Offset2, SecondOpc);
}
assert(Offset1 <= Offset2 && "Caller should have ordered offsets.");
return Offset1 + 1 == Offset2;
}
static const MachineInstrBuilder &AddSubReg(const MachineInstrBuilder &MIB,
unsigned Reg, unsigned SubIdx,