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llvm-project/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp

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//===- AArch64InstrInfo.cpp - AArch64 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 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/DebugLoc.h"
#include "llvm/IR/GlobalValue.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),
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();
if (MI.getOpcode() == AArch64::INLINEASM)
return getInlineAsmLength(MI.getOperand(0).getSymbolName(), *MAI);
// 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::DBG_VALUE:
case TargetOpcode::EH_LABEL:
case TargetOpcode::IMPLICIT_DEF:
case TargetOpcode::KILL:
NumBytes = 0;
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;
}
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 (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 = nullptr) {
VReg = removeCopies(MRI, VReg);
if (!TargetRegisterInfo::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;
}
unsigned 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();
if (Subtarget.hasExynosCheapAsMoveHandling()) {
if (isExynosResetFast(MI) || isExynosShiftLeftFast(MI))
return true;
else
return MI.isAsCheapAsAMove();
}
switch (MI.getOpcode()) {
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);
// It is cheap to zero out registers if the subtarget has ZeroCycleZeroing
// feature.
case AArch64::FMOVH0:
case AArch64::FMOVS0:
case AArch64::FMOVD0:
return Subtarget.hasZeroCycleZeroing();
case TargetOpcode::COPY:
return (Subtarget.hasZeroCycleZeroing() &&
(MI.getOperand(1).getReg() == AArch64::WZR ||
MI.getOperand(1).getReg() == AArch64::XZR));
}
llvm_unreachable("Unknown opcode to check as cheap as a move!");
}
bool AArch64InstrInfo::isExynosResetFast(const MachineInstr &MI) const {
unsigned Reg, Imm, Shift;
switch (MI.getOpcode()) {
default:
return false;
// MOV Rd, SP
case AArch64::ADDWri:
case AArch64::ADDXri:
if (!MI.getOperand(1).isReg() || !MI.getOperand(2).isImm())
return false;
Reg = MI.getOperand(1).getReg();
Imm = MI.getOperand(2).getImm();
return ((Reg == AArch64::WSP || Reg == AArch64::SP) && Imm == 0);
// Literal
case AArch64::ADR:
case AArch64::ADRP:
return true;
// MOVI Vd, #0
case AArch64::MOVID:
case AArch64::MOVIv8b_ns:
case AArch64::MOVIv2d_ns:
case AArch64::MOVIv16b_ns:
Imm = MI.getOperand(1).getImm();
return (Imm == 0);
// MOVI Vd, #0
case AArch64::MOVIv2i32:
case AArch64::MOVIv4i16:
case AArch64::MOVIv4i32:
case AArch64::MOVIv8i16:
Imm = MI.getOperand(1).getImm();
Shift = MI.getOperand(2).getImm();
return (Imm == 0 && Shift == 0);
// MOV Rd, Imm
case AArch64::MOVNWi:
case AArch64::MOVNXi:
// MOV Rd, Imm
case AArch64::MOVZWi:
case AArch64::MOVZXi:
return true;
// MOV Rd, Imm
case AArch64::ORRWri:
case AArch64::ORRXri:
if (!MI.getOperand(1).isReg())
return false;
Reg = MI.getOperand(1).getReg();
Imm = MI.getOperand(2).getImm();
return ((Reg == AArch64::WZR || Reg == AArch64::XZR) && Imm == 0);
// MOV Rd, Rm
case AArch64::ORRWrs:
case AArch64::ORRXrs:
if (!MI.getOperand(1).isReg())
return false;
Reg = MI.getOperand(1).getReg();
Imm = MI.getOperand(3).getImm();
Shift = AArch64_AM::getShiftValue(Imm);
return ((Reg == AArch64::WZR || Reg == AArch64::XZR) && Shift == 0);
}
}
bool AArch64InstrInfo::isExynosShiftLeftFast(const MachineInstr &MI) const {
unsigned Imm, Shift;
AArch64_AM::ShiftExtendType Ext;
switch (MI.getOpcode()) {
default:
return false;
// WriteI
case AArch64::ADDSWri:
case AArch64::ADDSXri:
case AArch64::ADDWri:
case AArch64::ADDXri:
case AArch64::SUBSWri:
case AArch64::SUBSXri:
case AArch64::SUBWri:
case AArch64::SUBXri:
return true;
// WriteISReg
case AArch64::ADDSWrs:
case AArch64::ADDSXrs:
case AArch64::ADDWrs:
case AArch64::ADDXrs:
case AArch64::ANDSWrs:
case AArch64::ANDSXrs:
case AArch64::ANDWrs:
case AArch64::ANDXrs:
case AArch64::BICSWrs:
case AArch64::BICSXrs:
case AArch64::BICWrs:
case AArch64::BICXrs:
case AArch64::EONWrs:
case AArch64::EONXrs:
case AArch64::EORWrs:
case AArch64::EORXrs:
case AArch64::ORNWrs:
case AArch64::ORNXrs:
case AArch64::ORRWrs:
case AArch64::ORRXrs:
case AArch64::SUBSWrs:
case AArch64::SUBSXrs:
case AArch64::SUBWrs:
case AArch64::SUBXrs:
Imm = MI.getOperand(3).getImm();
Shift = AArch64_AM::getShiftValue(Imm);
Ext = AArch64_AM::getShiftType(Imm);
return (Shift == 0 || (Shift <= 3 && Ext == AArch64_AM::LSL));
// WriteIEReg
case AArch64::ADDSWrx:
case AArch64::ADDSXrx:
case AArch64::ADDSXrx64:
case AArch64::ADDWrx:
case AArch64::ADDXrx:
case AArch64::ADDXrx64:
case AArch64::SUBSWrx:
case AArch64::SUBSXrx:
case AArch64::SUBSXrx64:
case AArch64::SUBWrx:
case AArch64::SUBXrx:
case AArch64::SUBXrx64:
Imm = MI.getOperand(3).getImm();
Shift = AArch64_AM::getArithShiftValue(Imm);
Ext = AArch64_AM::getArithExtendType(Imm);
return (Shift == 0 || (Shift <= 3 && Ext == AArch64_AM::UXTX));
case AArch64::PRFMroW:
case AArch64::PRFMroX:
// WriteLDIdx
case AArch64::LDRBBroW:
case AArch64::LDRBBroX:
case AArch64::LDRHHroW:
case AArch64::LDRHHroX:
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::LDRWroW:
case AArch64::LDRWroX:
case AArch64::LDRXroW:
case AArch64::LDRXroX:
case AArch64::LDRBroW:
case AArch64::LDRBroX:
case AArch64::LDRDroW:
case AArch64::LDRDroX:
case AArch64::LDRHroW:
case AArch64::LDRHroX:
case AArch64::LDRSroW:
case AArch64::LDRSroX:
// WriteSTIdx
case AArch64::STRBBroW:
case AArch64::STRBBroX:
case AArch64::STRHHroW:
case AArch64::STRHHroX:
case AArch64::STRWroW:
case AArch64::STRWroX:
case AArch64::STRXroW:
case AArch64::STRXroX:
case AArch64::STRBroW:
case AArch64::STRBroX:
case AArch64::STRDroW:
case AArch64::STRDroX:
case AArch64::STRHroW:
case AArch64::STRHroX:
case AArch64::STRSroW:
case AArch64::STRSroX:
Imm = MI.getOperand(3).getImm();
Ext = AArch64_AM::getMemExtendType(Imm);
return (Ext == AArch64_AM::SXTX || Ext == AArch64_AM::UXTX);
}
}
bool AArch64InstrInfo::isFalkorShiftExtFast(const MachineInstr &MI) const {
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::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(
MachineInstr &MIa, MachineInstr &MIb, AliasAnalysis *AA) const {
const TargetRegisterInfo *TRI = &getRegisterInfo();
unsigned BaseRegA = 0, BaseRegB = 0;
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 register, offset from the base register and width. Width
// is the size of memory that is being loaded/stored (e.g. 1, 2, 4, 8). If
// base registers 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 (getMemOpBaseRegImmOfsWidth(MIa, BaseRegA, OffsetA, WidthA, TRI) &&
getMemOpBaseRegImmOfsWidth(MIb, BaseRegB, OffsetB, WidthB, TRI)) {
if (BaseRegA == BaseRegB) {
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;
}
/// 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!");
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;
}
/// 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)
return false;
MachineBasicBlock &MBB = *MI.getParent();
DebugLoc DL = MI.getDebugLoc();
unsigned Reg = MI.getOperand(0).getReg();
const GlobalValue *GV =
cast<GlobalValue>((*MI.memoperands_begin())->getValue());
const TargetMachine &TM = MBB.getParent()->getTarget();
unsigned char 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, AArch64II::MO_GOT);
BuildMI(MBB, MI, DL, get(AArch64::LDRXui), Reg)
.addReg(Reg, RegState::Kill)
.addImm(0)
.addMemOperand(*MI.memoperands_begin());
} else if (TM.getCodeModel() == CodeModel::Large) {
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 {
BuildMI(MBB, MI, DL, get(AArch64::ADRP), Reg)
.addGlobalAddress(GV, 0, OpFlags | AArch64II::MO_PAGE);
unsigned char LoFlags = OpFlags | AArch64II::MO_PAGEOFF | MO_NC;
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 is this instruction has a non-zero immediate
bool AArch64InstrInfo::hasShiftedReg(const MachineInstr &MI) {
switch (MI.getOpcode()) {
default:
break;
case AArch64::ADDSWrs:
case AArch64::ADDSXrs:
case AArch64::ADDWrs:
case AArch64::ADDXrs:
case AArch64::ANDSWrs:
case AArch64::ANDSXrs:
case AArch64::ANDWrs:
case AArch64::ANDXrs:
case AArch64::BICSWrs:
case AArch64::BICSXrs:
case AArch64::BICWrs:
case AArch64::BICXrs:
case AArch64::EONWrs:
case AArch64::EONXrs:
case AArch64::EORWrs:
case AArch64::EORXrs:
case AArch64::ORNWrs:
case AArch64::ORNXrs:
case AArch64::ORRWrs:
case AArch64::ORRXrs:
case AArch64::SUBSWrs:
case AArch64::SUBSXrs:
case AArch64::SUBWrs:
case AArch64::SUBXrs:
if (MI.getOperand(3).isImm()) {
unsigned val = MI.getOperand(3).getImm();
return (val != 0);
}
break;
}
return false;
}
/// Return true if this is this instruction has a non-zero immediate
bool AArch64InstrInfo::hasExtendedReg(const MachineInstr &MI) {
switch (MI.getOpcode()) {
default:
break;
case AArch64::ADDSWrx:
case AArch64::ADDSXrx:
case AArch64::ADDSXrx64:
case AArch64::ADDWrx:
case AArch64::ADDXrx:
case AArch64::ADDXrx64:
case AArch64::SUBSWrx:
case AArch64::SUBSXrx:
case AArch64::SUBSXrx64:
case AArch64::SUBWrx:
case AArch64::SUBXrx:
case AArch64::SUBXrx64:
if (MI.getOperand(3).isImm()) {
unsigned val = MI.getOperand(3).getImm();
return (val != 0);
}
break;
}
return false;
}
// 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
unsigned 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
unsigned 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;
}
/// 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 AArch64InstrInfo::isScaledAddr(const MachineInstr &MI) {
switch (MI.getOpcode()) {
default:
break;
case AArch64::LDRBBroW:
case AArch64::LDRBroW:
case AArch64::LDRDroW:
case AArch64::LDRHHroW:
case AArch64::LDRHroW:
case AArch64::LDRQroW:
case AArch64::LDRSBWroW:
case AArch64::LDRSBXroW:
case AArch64::LDRSHWroW:
case AArch64::LDRSHXroW:
case AArch64::LDRSWroW:
case AArch64::LDRSroW:
case AArch64::LDRWroW:
case AArch64::LDRXroW:
case AArch64::STRBBroW:
case AArch64::STRBroW:
case AArch64::STRDroW:
case AArch64::STRHHroW:
case AArch64::STRHroW:
case AArch64::STRQroW:
case AArch64::STRSroW:
case AArch64::STRWroW:
case AArch64::STRXroW:
case AArch64::LDRBBroX:
case AArch64::LDRBroX:
case AArch64::LDRDroX:
case AArch64::LDRHHroX:
case AArch64::LDRHroX:
case AArch64::LDRQroX:
case AArch64::LDRSBWroX:
case AArch64::LDRSBXroX:
case AArch64::LDRSHWroX:
case AArch64::LDRSHXroX:
case AArch64::LDRSWroX:
case AArch64::LDRSroX:
case AArch64::LDRWroX:
case AArch64::LDRXroX:
case AArch64::STRBBroX:
case AArch64::STRBroX:
case AArch64::STRDroX:
case AArch64::STRHHroX:
case AArch64::STRHroX:
case AArch64::STRQroX:
case AArch64::STRSroX:
case AArch64::STRWroX:
case AArch64::STRXroX:
unsigned Val = MI.getOperand(3).getImm();
AArch64_AM::ShiftExtendType ExtType = AArch64_AM::getMemExtendType(Val);
return (ExtType != AArch64_AM::UXTX) || AArch64_AM::getMemDoShift(Val);
}
return false;
}
/// 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;
}
}
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(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+imm (as opposed to an address reloc).
assert(MI.getOperand(1).isReg() && "Expected a reg operand.");
if (!MI.getOperand(2).isImm())
return false;
// Can't merge/pair if the instruction modifies the base register.
// e.g., ldr x0, [x0]
unsigned 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;
// 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::getMemOpBaseRegImmOfs(
MachineInstr &LdSt, unsigned &BaseReg, int64_t &Offset,
const TargetRegisterInfo *TRI) const {
unsigned Width;
return getMemOpBaseRegImmOfsWidth(LdSt, BaseReg, Offset, Width, TRI);
}
bool AArch64InstrInfo::getMemOpBaseRegImmOfsWidth(
MachineInstr &LdSt, unsigned &BaseReg, 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(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(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) {
BaseReg = LdSt.getOperand(1).getReg();
Offset = LdSt.getOperand(2).getImm() * Scale;
} else {
assert(LdSt.getNumExplicitOperands() == 4 && "invalid number of operands");
BaseReg = LdSt.getOperand(2).getReg();
Offset = LdSt.getOperand(3).getImm() * Scale;
}
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) const {
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::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::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::STRHui:
case AArch64::STRHHui:
Scale = Width = 2;
MinOffset = 0;
MaxOffset = 4095;
break;
case AArch64::LDRBui:
case AArch64::LDRBBui:
case AArch64::STRBui:
case AArch64::STRBBui:
Scale = Width = 1;
MinOffset = 0;
MaxOffset = 4095;
break;
}
return true;
}
// Scale the unscaled offsets. Returns false if the unscaled offset can't be
// scaled.
static bool scaleOffset(unsigned Opc, int64_t &Offset) {
unsigned OffsetStride = 1;
switch (Opc) {
default:
return false;
case AArch64::LDURQi:
case AArch64::STURQi:
OffsetStride = 16;
break;
case AArch64::LDURXi:
case AArch64::LDURDi:
case AArch64::STURXi:
case AArch64::STURDi:
OffsetStride = 8;
break;
case AArch64::LDURWi:
case AArch64::LDURSi:
case AArch64::LDURSWi:
case AArch64::STURWi:
case AArch64::STURSi:
OffsetStride = 4;
break;
}
// If the byte-offset isn't a multiple of the stride, we can't scale this
// offset.
if (Offset % OffsetStride != 0)
return false;
// Convert the byte-offset used by unscaled into an "element" offset used
// by the scaled pair load/store instructions.
Offset /= OffsetStride;
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;
}
/// Detect opportunities for ldp/stp formation.
///
/// Only called for LdSt for which getMemOpBaseRegImmOfs returns true.
bool AArch64InstrInfo::shouldClusterMemOps(MachineInstr &FirstLdSt,
unsigned BaseReg1,
MachineInstr &SecondLdSt,
unsigned BaseReg2,
unsigned NumLoads) const {
if (BaseReg1 != BaseReg2)
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.
assert(Offset1 <= Offset2 && "Caller should have ordered offsets.");
return Offset1 + 1 == Offset2;
}
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 AArch64InstrInfo::copyPhysRegTuple(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
const DebugLoc &DL, unsigned DestReg,
unsigned SrcReg, bool KillSrc,
unsigned Opcode,
ArrayRef<unsigned> Indices) const {
assert(Subtarget.hasNEON() && "Unexpected register copy without NEON");
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 AArch64InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
const DebugLoc &DL, unsigned DestReg,
unsigned SrcReg, bool KillSrc) const {
if (AArch64::GPR32spRegClass.contains(DestReg) &&
(AArch64::GPR32spRegClass.contains(SrcReg) || SrcReg == AArch64::WZR)) {
const TargetRegisterInfo *TRI = &getRegisterInfo();
if (DestReg == AArch64::WSP || SrcReg == AArch64::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, AArch64::sub_32,
&AArch64::GPR64spRegClass);
unsigned SrcRegX = TRI->getMatchingSuperReg(SrcReg, AArch64::sub_32,
&AArch64::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(AArch64::ADDXri), DestRegX)
.addReg(SrcRegX, RegState::Undef)
.addImm(0)
.addImm(AArch64_AM::getShifterImm(AArch64_AM::LSL, 0))
.addReg(SrcReg, RegState::Implicit | getKillRegState(KillSrc));
} else {
BuildMI(MBB, I, DL, get(AArch64::ADDWri), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc))
.addImm(0)
.addImm(AArch64_AM::getShifterImm(AArch64_AM::LSL, 0));
}
} else if (SrcReg == AArch64::WZR && Subtarget.hasZeroCycleZeroing()) {
BuildMI(MBB, I, DL, get(AArch64::MOVZWi), DestReg)
.addImm(0)
.addImm(AArch64_AM::getShifterImm(AArch64_AM::LSL, 0));
} else {
if (Subtarget.hasZeroCycleRegMove()) {
// Cyclone recognizes "ORR Xd, XZR, Xm" as a zero-cycle register move.
unsigned DestRegX = TRI->getMatchingSuperReg(DestReg, AArch64::sub_32,
&AArch64::GPR64spRegClass);
unsigned SrcRegX = TRI->getMatchingSuperReg(SrcReg, AArch64::sub_32,
&AArch64::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(AArch64::ORRXrr), DestRegX)
.addReg(AArch64::XZR)
.addReg(SrcRegX, RegState::Undef)
.addReg(SrcReg, RegState::Implicit | getKillRegState(KillSrc));
} else {
// Otherwise, expand to ORR WZR.
BuildMI(MBB, I, DL, get(AArch64::ORRWrr), DestReg)
.addReg(AArch64::WZR)
.addReg(SrcReg, getKillRegState(KillSrc));
}
}
return;
}
if (AArch64::GPR64spRegClass.contains(DestReg) &&
(AArch64::GPR64spRegClass.contains(SrcReg) || SrcReg == AArch64::XZR)) {
if (DestReg == AArch64::SP || SrcReg == AArch64::SP) {
// If either operand is SP, expand to ADD #0.
BuildMI(MBB, I, DL, get(AArch64::ADDXri), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc))
.addImm(0)
.addImm(AArch64_AM::getShifterImm(AArch64_AM::LSL, 0));
} else if (SrcReg == AArch64::XZR && Subtarget.hasZeroCycleZeroing()) {
BuildMI(MBB, I, DL, get(AArch64::MOVZXi), DestReg)
.addImm(0)
.addImm(AArch64_AM::getShifterImm(AArch64_AM::LSL, 0));
} else {
// Otherwise, expand to ORR XZR.
BuildMI(MBB, I, DL, get(AArch64::ORRXrr), DestReg)
.addReg(AArch64::XZR)
.addReg(SrcReg, getKillRegState(KillSrc));
}
return;
}
// Copy a DDDD register quad by copying the individual sub-registers.
if (AArch64::DDDDRegClass.contains(DestReg) &&
AArch64::DDDDRegClass.contains(SrcReg)) {
static const unsigned Indices[] = {AArch64::dsub0, AArch64::dsub1,
AArch64::dsub2, AArch64::dsub3};
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, AArch64::ORRv8i8,
Indices);
return;
}
// Copy a DDD register triple by copying the individual sub-registers.
if (AArch64::DDDRegClass.contains(DestReg) &&
AArch64::DDDRegClass.contains(SrcReg)) {
static const unsigned Indices[] = {AArch64::dsub0, AArch64::dsub1,
AArch64::dsub2};
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, AArch64::ORRv8i8,
Indices);
return;
}
// Copy a DD register pair by copying the individual sub-registers.
if (AArch64::DDRegClass.contains(DestReg) &&
AArch64::DDRegClass.contains(SrcReg)) {
static const unsigned Indices[] = {AArch64::dsub0, AArch64::dsub1};
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, AArch64::ORRv8i8,
Indices);
return;
}
// Copy a QQQQ register quad by copying the individual sub-registers.
if (AArch64::QQQQRegClass.contains(DestReg) &&
AArch64::QQQQRegClass.contains(SrcReg)) {
static const unsigned Indices[] = {AArch64::qsub0, AArch64::qsub1,
AArch64::qsub2, AArch64::qsub3};
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, AArch64::ORRv16i8,
Indices);
return;
}
// Copy a QQQ register triple by copying the individual sub-registers.
if (AArch64::QQQRegClass.contains(DestReg) &&
AArch64::QQQRegClass.contains(SrcReg)) {
static const unsigned Indices[] = {AArch64::qsub0, AArch64::qsub1,
AArch64::qsub2};
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, AArch64::ORRv16i8,
Indices);
return;
}
// Copy a QQ register pair by copying the individual sub-registers.
if (AArch64::QQRegClass.contains(DestReg) &&
AArch64::QQRegClass.contains(SrcReg)) {
static const unsigned Indices[] = {AArch64::qsub0, AArch64::qsub1};
copyPhysRegTuple(MBB, I, DL, DestReg, SrcReg, KillSrc, AArch64::ORRv16i8,
Indices);
return;
}
if (AArch64::FPR128RegClass.contains(DestReg) &&
AArch64::FPR128RegClass.contains(SrcReg)) {
if (Subtarget.hasNEON()) {
BuildMI(MBB, I, DL, get(AArch64::ORRv16i8), DestReg)
.addReg(SrcReg)
.addReg(SrcReg, getKillRegState(KillSrc));
} else {
BuildMI(MBB, I, DL, get(AArch64::STRQpre))
.addReg(AArch64::SP, RegState::Define)
.addReg(SrcReg, getKillRegState(KillSrc))
.addReg(AArch64::SP)
.addImm(-16);
BuildMI(MBB, I, DL, get(AArch64::LDRQpre))
.addReg(AArch64::SP, RegState::Define)
.addReg(DestReg, RegState::Define)
.addReg(AArch64::SP)
.addImm(16);
}
return;
}
if (AArch64::FPR64RegClass.contains(DestReg) &&
AArch64::FPR64RegClass.contains(SrcReg)) {
if (Subtarget.hasNEON()) {
DestReg = RI.getMatchingSuperReg(DestReg, AArch64::dsub,
&AArch64::FPR128RegClass);
SrcReg = RI.getMatchingSuperReg(SrcReg, AArch64::dsub,
&AArch64::FPR128RegClass);
BuildMI(MBB, I, DL, get(AArch64::ORRv16i8), DestReg)
.addReg(SrcReg)
.addReg(SrcReg, getKillRegState(KillSrc));
} else {
BuildMI(MBB, I, DL, get(AArch64::FMOVDr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
}
return;
}
if (AArch64::FPR32RegClass.contains(DestReg) &&
AArch64::FPR32RegClass.contains(SrcReg)) {
if (Subtarget.hasNEON()) {
DestReg = RI.getMatchingSuperReg(DestReg, AArch64::ssub,
&AArch64::FPR128RegClass);
SrcReg = RI.getMatchingSuperReg(SrcReg, AArch64::ssub,
&AArch64::FPR128RegClass);
BuildMI(MBB, I, DL, get(AArch64::ORRv16i8), DestReg)
.addReg(SrcReg)
.addReg(SrcReg, getKillRegState(KillSrc));
} else {
BuildMI(MBB, I, DL, get(AArch64::FMOVSr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
}
return;
}
if (AArch64::FPR16RegClass.contains(DestReg) &&
AArch64::FPR16RegClass.contains(SrcReg)) {
if (Subtarget.hasNEON()) {
DestReg = RI.getMatchingSuperReg(DestReg, AArch64::hsub,
&AArch64::FPR128RegClass);
SrcReg = RI.getMatchingSuperReg(SrcReg, AArch64::hsub,
&AArch64::FPR128RegClass);
BuildMI(MBB, I, DL, get(AArch64::ORRv16i8), DestReg)
.addReg(SrcReg)
.addReg(SrcReg, getKillRegState(KillSrc));
} else {
DestReg = RI.getMatchingSuperReg(DestReg, AArch64::hsub,
&AArch64::FPR32RegClass);
SrcReg = RI.getMatchingSuperReg(SrcReg, AArch64::hsub,
&AArch64::FPR32RegClass);
BuildMI(MBB, I, DL, get(AArch64::FMOVSr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
}
return;
}
if (AArch64::FPR8RegClass.contains(DestReg) &&
AArch64::FPR8RegClass.contains(SrcReg)) {
if (Subtarget.hasNEON()) {
DestReg = RI.getMatchingSuperReg(DestReg, AArch64::bsub,
&AArch64::FPR128RegClass);
SrcReg = RI.getMatchingSuperReg(SrcReg, AArch64::bsub,
&AArch64::FPR128RegClass);
BuildMI(MBB, I, DL, get(AArch64::ORRv16i8), DestReg)
.addReg(SrcReg)
.addReg(SrcReg, getKillRegState(KillSrc));
} else {
DestReg = RI.getMatchingSuperReg(DestReg, AArch64::bsub,
&AArch64::FPR32RegClass);
SrcReg = RI.getMatchingSuperReg(SrcReg, AArch64::bsub,
&AArch64::FPR32RegClass);
BuildMI(MBB, I, DL, get(AArch64::FMOVSr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
}
return;
}
// Copies between GPR64 and FPR64.
if (AArch64::FPR64RegClass.contains(DestReg) &&
AArch64::GPR64RegClass.contains(SrcReg)) {
BuildMI(MBB, I, DL, get(AArch64::FMOVXDr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
return;
}
if (AArch64::GPR64RegClass.contains(DestReg) &&
AArch64::FPR64RegClass.contains(SrcReg)) {
BuildMI(MBB, I, DL, get(AArch64::FMOVDXr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
return;
}
// Copies between GPR32 and FPR32.
if (AArch64::FPR32RegClass.contains(DestReg) &&
AArch64::GPR32RegClass.contains(SrcReg)) {
BuildMI(MBB, I, DL, get(AArch64::FMOVWSr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
return;
}
if (AArch64::GPR32RegClass.contains(DestReg) &&
AArch64::FPR32RegClass.contains(SrcReg)) {
BuildMI(MBB, I, DL, get(AArch64::FMOVSWr), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
return;
}
if (DestReg == AArch64::NZCV) {
assert(AArch64::GPR64RegClass.contains(SrcReg) && "Invalid NZCV copy");
BuildMI(MBB, I, DL, get(AArch64::MSR))
.addImm(AArch64SysReg::NZCV)
.addReg(SrcReg, getKillRegState(KillSrc))
.addReg(AArch64::NZCV, RegState::Implicit | RegState::Define);
return;
}
if (SrcReg == AArch64::NZCV) {
assert(AArch64::GPR64RegClass.contains(DestReg) && "Invalid NZCV copy");
BuildMI(MBB, I, DL, get(AArch64::MRS), DestReg)
.addImm(AArch64SysReg::NZCV)
.addReg(AArch64::NZCV, RegState::Implicit | getKillRegState(KillSrc));
return;
}
llvm_unreachable("unimplemented reg-to-reg copy");
}
void AArch64InstrInfo::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 = MachinePointerInfo::getFixedStack(MF, FI);
MachineMemOperand *MMO = MF.getMachineMemOperand(
PtrInfo, MachineMemOperand::MOStore, MFI.getObjectSize(FI), Align);
unsigned Opc = 0;
bool Offset = true;
switch (TRI->getSpillSize(*RC)) {
case 1:
if (AArch64::FPR8RegClass.hasSubClassEq(RC))
Opc = AArch64::STRBui;
break;
case 2:
if (AArch64::FPR16RegClass.hasSubClassEq(RC))
Opc = AArch64::STRHui;
break;
case 4:
if (AArch64::GPR32allRegClass.hasSubClassEq(RC)) {
Opc = AArch64::STRWui;
if (TargetRegisterInfo::isVirtualRegister(SrcReg))
MF.getRegInfo().constrainRegClass(SrcReg, &AArch64::GPR32RegClass);
else
assert(SrcReg != AArch64::WSP);
} else if (AArch64::FPR32RegClass.hasSubClassEq(RC))
Opc = AArch64::STRSui;
break;
case 8:
if (AArch64::GPR64allRegClass.hasSubClassEq(RC)) {
Opc = AArch64::STRXui;
if (TargetRegisterInfo::isVirtualRegister(SrcReg))
MF.getRegInfo().constrainRegClass(SrcReg, &AArch64::GPR64RegClass);
else
assert(SrcReg != AArch64::SP);
} else if (AArch64::FPR64RegClass.hasSubClassEq(RC))
Opc = AArch64::STRDui;
break;
case 16:
if (AArch64::FPR128RegClass.hasSubClassEq(RC))
Opc = AArch64::STRQui;
else if (AArch64::DDRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register store without NEON");
Opc = AArch64::ST1Twov1d;
Offset = false;
} else if (AArch64::XSeqPairsClassRegClass.hasSubClassEq(RC)) {
BuildMI(MBB, MBBI, DL, get(AArch64::STPXi))
.addReg(TRI->getSubReg(SrcReg, AArch64::sube64),
getKillRegState(isKill))
.addReg(TRI->getSubReg(SrcReg, AArch64::subo64),
getKillRegState(isKill))
.addFrameIndex(FI)
.addImm(0)
.addMemOperand(MMO);
return;
}
break;
case 24:
if (AArch64::DDDRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register store without NEON");
Opc = AArch64::ST1Threev1d;
Offset = false;
}
break;
case 32:
if (AArch64::DDDDRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register store without NEON");
Opc = AArch64::ST1Fourv1d;
Offset = false;
} else if (AArch64::QQRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register store without NEON");
Opc = AArch64::ST1Twov2d;
Offset = false;
}
break;
case 48:
if (AArch64::QQQRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register store without NEON");
Opc = AArch64::ST1Threev2d;
Offset = false;
}
break;
case 64:
if (AArch64::QQQQRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register store without NEON");
Opc = AArch64::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 AArch64InstrInfo::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 = MachinePointerInfo::getFixedStack(MF, FI);
MachineMemOperand *MMO = MF.getMachineMemOperand(
PtrInfo, MachineMemOperand::MOLoad, MFI.getObjectSize(FI), Align);
unsigned Opc = 0;
bool Offset = true;
switch (TRI->getSpillSize(*RC)) {
case 1:
if (AArch64::FPR8RegClass.hasSubClassEq(RC))
Opc = AArch64::LDRBui;
break;
case 2:
if (AArch64::FPR16RegClass.hasSubClassEq(RC))
Opc = AArch64::LDRHui;
break;
case 4:
if (AArch64::GPR32allRegClass.hasSubClassEq(RC)) {
Opc = AArch64::LDRWui;
if (TargetRegisterInfo::isVirtualRegister(DestReg))
MF.getRegInfo().constrainRegClass(DestReg, &AArch64::GPR32RegClass);
else
assert(DestReg != AArch64::WSP);
} else if (AArch64::FPR32RegClass.hasSubClassEq(RC))
Opc = AArch64::LDRSui;
break;
case 8:
if (AArch64::GPR64allRegClass.hasSubClassEq(RC)) {
Opc = AArch64::LDRXui;
if (TargetRegisterInfo::isVirtualRegister(DestReg))
MF.getRegInfo().constrainRegClass(DestReg, &AArch64::GPR64RegClass);
else
assert(DestReg != AArch64::SP);
} else if (AArch64::FPR64RegClass.hasSubClassEq(RC))
Opc = AArch64::LDRDui;
break;
case 16:
if (AArch64::FPR128RegClass.hasSubClassEq(RC))
Opc = AArch64::LDRQui;
else if (AArch64::DDRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register load without NEON");
Opc = AArch64::LD1Twov1d;
Offset = false;
} else if (AArch64::XSeqPairsClassRegClass.hasSubClassEq(RC)) {
BuildMI(MBB, MBBI, DL, get(AArch64::LDPXi))
.addReg(TRI->getSubReg(DestReg, AArch64::sube64),
getDefRegState(true))
.addReg(TRI->getSubReg(DestReg, AArch64::subo64),
getDefRegState(true))
.addFrameIndex(FI)
.addImm(0)
.addMemOperand(MMO);
return;
}
break;
case 24:
if (AArch64::DDDRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register load without NEON");
Opc = AArch64::LD1Threev1d;
Offset = false;
}
break;
case 32:
if (AArch64::DDDDRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register load without NEON");
Opc = AArch64::LD1Fourv1d;
Offset = false;
} else if (AArch64::QQRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register load without NEON");
Opc = AArch64::LD1Twov2d;
Offset = false;
}
break;
case 48:
if (AArch64::QQQRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register load without NEON");
Opc = AArch64::LD1Threev2d;
Offset = false;
}
break;
case 64:
if (AArch64::QQQQRegClass.hasSubClassEq(RC)) {
assert(Subtarget.hasNEON() && "Unexpected register load without NEON");
Opc = AArch64::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, const DebugLoc &DL,
unsigned DestReg, unsigned SrcReg, int Offset,
const TargetInstrInfo *TII,
MachineInstr::MIFlag Flag, bool SetNZCV) {
if (DestReg == SrcReg && Offset == 0)
return;
assert((DestReg != AArch64::SP || Offset % 16 == 0) &&
"SP increment/decrement not 16-byte aligned");
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 (SetNZCV)
Opc = isSub ? AArch64::SUBSXri : AArch64::ADDSXri;
else
Opc = isSub ? AArch64::SUBXri : AArch64::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(AArch64_AM::getShifterImm(AArch64_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(AArch64_AM::getShifterImm(AArch64_AM::LSL, 0))
.setMIFlag(Flag);
}
MachineInstr *AArch64InstrInfo::foldMemoryOperandImpl(
MachineFunction &MF, MachineInstr &MI, ArrayRef<unsigned> Ops,
MachineBasicBlock::iterator InsertPt, int FrameIndex,
LiveIntervals *LIS) const {
// This is a bit of a hack. Consider this instruction:
//
// %0 = COPY %sp; GPR64all:%0
//
// We explicitly chose GPR64all for the virtual register so such a copy might
// be eliminated by RegisterCoalescer. However, that may not be possible, and
// %0 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 %0 register class here.
//
// <rdar://problem/11522048>
//
if (MI.isFullCopy()) {
unsigned DstReg = MI.getOperand(0).getReg();
unsigned SrcReg = MI.getOperand(1).getReg();
if (SrcReg == AArch64::SP &&
TargetRegisterInfo::isVirtualRegister(DstReg)) {
MF.getRegInfo().constrainRegClass(DstReg, &AArch64::GPR64RegClass);
return nullptr;
}
if (DstReg == AArch64::SP &&
TargetRegisterInfo::isVirtualRegister(SrcReg)) {
MF.getRegInfo().constrainRegClass(SrcReg, &AArch64::GPR64RegClass);
return nullptr;
}
}
// Handle the case where a copy is being spilled or filled but the source
// and destination register class don't match. For example:
//
// %0 = COPY %xzr; GPR64common:%0
//
// In this case we can still safely fold away the COPY and generate the
// following spill code:
//
// STRXui %xzr, %stack.0
//
// This also eliminates spilled cross register class COPYs (e.g. between x and
// d regs) of the same size. For example:
//
// %0 = COPY %1; GPR64:%0, FPR64:%1
//
// will be filled as
//
// LDRDui %0, fi<#0>
//
// instead of
//
// LDRXui %Temp, fi<#0>
// %0 = FMOV %Temp
//
if (MI.isCopy() && Ops.size() == 1 &&
// Make sure we're only folding the explicit COPY defs/uses.
(Ops[0] == 0 || Ops[0] == 1)) {
bool IsSpill = Ops[0] == 0;
bool IsFill = !IsSpill;
const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
const MachineRegisterInfo &MRI = MF.getRegInfo();
MachineBasicBlock &MBB = *MI.getParent();
const MachineOperand &DstMO = MI.getOperand(0);
const MachineOperand &SrcMO = MI.getOperand(1);
unsigned DstReg = DstMO.getReg();
unsigned SrcReg = SrcMO.getReg();
// This is slightly expensive to compute for physical regs since
// getMinimalPhysRegClass is slow.
auto getRegClass = [&](unsigned Reg) {
return TargetRegisterInfo::isVirtualRegister(Reg)
? MRI.getRegClass(Reg)
: TRI.getMinimalPhysRegClass(Reg);
};
if (DstMO.getSubReg() == 0 && SrcMO.getSubReg() == 0) {
assert(TRI.getRegSizeInBits(*getRegClass(DstReg)) ==
TRI.getRegSizeInBits(*getRegClass(SrcReg)) &&
"Mismatched register size in non subreg COPY");
if (IsSpill)
storeRegToStackSlot(MBB, InsertPt, SrcReg, SrcMO.isKill(), FrameIndex,
getRegClass(SrcReg), &TRI);
else
loadRegFromStackSlot(MBB, InsertPt, DstReg, FrameIndex,
getRegClass(DstReg), &TRI);
return &*--InsertPt;
}
// Handle cases like spilling def of:
//
// %0:sub_32<def,read-undef> = COPY %wzr; GPR64common:%0
//
// where the physical register source can be widened and stored to the full
// virtual reg destination stack slot, in this case producing:
//
// STRXui %xzr, %stack.0
//
if (IsSpill && DstMO.isUndef() &&
TargetRegisterInfo::isPhysicalRegister(SrcReg)) {
assert(SrcMO.getSubReg() == 0 &&
"Unexpected subreg on physical register");
const TargetRegisterClass *SpillRC;
unsigned SpillSubreg;
switch (DstMO.getSubReg()) {
default:
SpillRC = nullptr;
break;
case AArch64::sub_32:
case AArch64::ssub:
if (AArch64::GPR32RegClass.contains(SrcReg)) {
SpillRC = &AArch64::GPR64RegClass;
SpillSubreg = AArch64::sub_32;
} else if (AArch64::FPR32RegClass.contains(SrcReg)) {
SpillRC = &AArch64::FPR64RegClass;
SpillSubreg = AArch64::ssub;
} else
SpillRC = nullptr;
break;
case AArch64::dsub:
if (AArch64::FPR64RegClass.contains(SrcReg)) {
SpillRC = &AArch64::FPR128RegClass;
SpillSubreg = AArch64::dsub;
} else
SpillRC = nullptr;
break;
}
if (SpillRC)
if (unsigned WidenedSrcReg =
TRI.getMatchingSuperReg(SrcReg, SpillSubreg, SpillRC)) {
storeRegToStackSlot(MBB, InsertPt, WidenedSrcReg, SrcMO.isKill(),
FrameIndex, SpillRC, &TRI);
return &*--InsertPt;
}
}
// Handle cases like filling use of:
//
// %0:sub_32<def,read-undef> = COPY %1; GPR64:%0, GPR32:%1
//
// where we can load the full virtual reg source stack slot, into the subreg
// destination, in this case producing:
//
// LDRWui %0:sub_32<def,read-undef>, %stack.0
//
if (IsFill && SrcMO.getSubReg() == 0 && DstMO.isUndef()) {
const TargetRegisterClass *FillRC;
switch (DstMO.getSubReg()) {
default:
FillRC = nullptr;
break;
case AArch64::sub_32:
FillRC = &AArch64::GPR32RegClass;
break;
case AArch64::ssub:
FillRC = &AArch64::FPR32RegClass;
break;
case AArch64::dsub:
FillRC = &AArch64::FPR64RegClass;
break;
}
if (FillRC) {
assert(TRI.getRegSizeInBits(*getRegClass(SrcReg)) ==
TRI.getRegSizeInBits(*FillRC) &&
"Mismatched regclass size on folded subreg COPY");
loadRegFromStackSlot(MBB, InsertPt, DstReg, FrameIndex, FillRC, &TRI);
MachineInstr &LoadMI = *--InsertPt;
MachineOperand &LoadDst = LoadMI.getOperand(0);
assert(LoadDst.getSubReg() == 0 && "unexpected subreg on fill load");
LoadDst.setSubReg(DstMO.getSubReg());
LoadDst.setIsUndef();
return &LoadMI;
}
}
}
// Cannot fold.
return nullptr;
}
int llvm::isAArch64FrameOffsetLegal(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:
llvm_unreachable("unhandled opcode in rewriteAArch64FrameIndex");
// Vector spills/fills can't take an immediate offset.
case AArch64::LD1Twov2d:
case AArch64::LD1Threev2d:
case AArch64::LD1Fourv2d:
case AArch64::LD1Twov1d:
case AArch64::LD1Threev1d:
case AArch64::LD1Fourv1d:
case AArch64::ST1Twov2d:
case AArch64::ST1Threev2d:
case AArch64::ST1Fourv2d:
case AArch64::ST1Twov1d:
case AArch64::ST1Threev1d:
case AArch64::ST1Fourv1d:
return AArch64FrameOffsetCannotUpdate;
case AArch64::PRFMui:
Scale = 8;
UnscaledOp = AArch64::PRFUMi;
break;
case AArch64::LDRXui:
Scale = 8;
UnscaledOp = AArch64::LDURXi;
break;
case AArch64::LDRWui:
Scale = 4;
UnscaledOp = AArch64::LDURWi;
break;
case AArch64::LDRBui:
Scale = 1;
UnscaledOp = AArch64::LDURBi;
break;
case AArch64::LDRHui:
Scale = 2;
UnscaledOp = AArch64::LDURHi;
break;
case AArch64::LDRSui:
Scale = 4;
UnscaledOp = AArch64::LDURSi;
break;
case AArch64::LDRDui:
Scale = 8;
UnscaledOp = AArch64::LDURDi;
break;
case AArch64::LDRQui:
Scale = 16;
UnscaledOp = AArch64::LDURQi;
break;
case AArch64::LDRBBui:
Scale = 1;
UnscaledOp = AArch64::LDURBBi;
break;
case AArch64::LDRHHui:
Scale = 2;
UnscaledOp = AArch64::LDURHHi;
break;
case AArch64::LDRSBXui:
Scale = 1;
UnscaledOp = AArch64::LDURSBXi;
break;
case AArch64::LDRSBWui:
Scale = 1;
UnscaledOp = AArch64::LDURSBWi;
break;
case AArch64::LDRSHXui:
Scale = 2;
UnscaledOp = AArch64::LDURSHXi;
break;
case AArch64::LDRSHWui:
Scale = 2;
UnscaledOp = AArch64::LDURSHWi;
break;
case AArch64::LDRSWui:
Scale = 4;
UnscaledOp = AArch64::LDURSWi;
break;
case AArch64::STRXui:
Scale = 8;
UnscaledOp = AArch64::STURXi;
break;
case AArch64::STRWui:
Scale = 4;
UnscaledOp = AArch64::STURWi;
break;
case AArch64::STRBui:
Scale = 1;
UnscaledOp = AArch64::STURBi;
break;
case AArch64::STRHui:
Scale = 2;
UnscaledOp = AArch64::STURHi;
break;
case AArch64::STRSui:
Scale = 4;
UnscaledOp = AArch64::STURSi;
break;
case AArch64::STRDui:
Scale = 8;
UnscaledOp = AArch64::STURDi;
break;
case AArch64::STRQui:
Scale = 16;
UnscaledOp = AArch64::STURQi;
break;
case AArch64::STRBBui:
Scale = 1;
UnscaledOp = AArch64::STURBBi;
break;
case AArch64::STRHHui:
Scale = 2;
UnscaledOp = AArch64::STURHHi;
break;
case AArch64::LDPXi:
case AArch64::LDPDi:
case AArch64::STPXi:
case AArch64::STPDi:
case AArch64::LDNPXi:
case AArch64::LDNPDi:
case AArch64::STNPXi:
case AArch64::STNPDi:
ImmIdx = 3;
IsSigned = true;
Scale = 8;
break;
case AArch64::LDPQi:
case AArch64::STPQi:
case AArch64::LDNPQi:
case AArch64::STNPQi:
ImmIdx = 3;
IsSigned = true;
Scale = 16;
break;
case AArch64::LDPWi:
case AArch64::LDPSi:
case AArch64::STPWi:
case AArch64::STPSi:
case AArch64::LDNPWi:
case AArch64::LDNPSi:
case AArch64::STNPWi:
case AArch64::STNPSi:
ImmIdx = 3;
IsSigned = true;
Scale = 4;
break;
case AArch64::LDURXi:
case AArch64::LDURWi:
case AArch64::LDURBi:
case AArch64::LDURHi:
case AArch64::LDURSi:
case AArch64::LDURDi:
case AArch64::LDURQi:
case AArch64::LDURHHi:
case AArch64::LDURBBi:
case AArch64::LDURSBXi:
case AArch64::LDURSBWi:
case AArch64::LDURSHXi:
case AArch64::LDURSHWi:
case AArch64::LDURSWi:
case AArch64::STURXi:
case AArch64::STURWi:
case AArch64::STURBi:
case AArch64::STURHi:
case AArch64::STURSi:
case AArch64::STURDi:
case AArch64::STURQi:
case AArch64::STURBBi:
case AArch64::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 AArch64FrameOffsetCanUpdate |
(Offset == 0 ? AArch64FrameOffsetIsLegal : 0);
}
bool llvm::rewriteAArch64FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
unsigned FrameReg, int &Offset,
const AArch64InstrInfo *TII) {
unsigned Opcode = MI.getOpcode();
unsigned ImmIdx = FrameRegIdx + 1;
if (Opcode == AArch64::ADDSXri || Opcode == AArch64::ADDXri) {
Offset += MI.getOperand(ImmIdx).getImm();
emitFrameOffset(*MI.getParent(), MI, MI.getDebugLoc(),
MI.getOperand(0).getReg(), FrameReg, Offset, TII,
MachineInstr::NoFlags, (Opcode == AArch64::ADDSXri));
MI.eraseFromParent();
Offset = 0;
return true;
}
int NewOffset;
unsigned UnscaledOp;
bool UseUnscaledOp;
int Status = isAArch64FrameOffsetLegal(MI, Offset, &UseUnscaledOp,
&UnscaledOp, &NewOffset);
if (Status & AArch64FrameOffsetCanUpdate) {
if (Status & AArch64FrameOffsetIsLegal)
// 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 AArch64InstrInfo::getNoop(MCInst &NopInst) const {
NopInst.setOpcode(AArch64::HINT);
NopInst.addOperand(MCOperand::createImm(0));
}
// AArch64 supports MachineCombiner.
bool AArch64InstrInfo::useMachineCombiner() const { return true; }
// True when Opc sets flag
static bool isCombineInstrSettingFlag(unsigned Opc) {
switch (Opc) {
case AArch64::ADDSWrr:
case AArch64::ADDSWri:
case AArch64::ADDSXrr:
case AArch64::ADDSXri:
case AArch64::SUBSWrr:
case AArch64::SUBSXrr:
// Note: MSUB Wd,Wn,Wm,Wi -> Wd = Wi - WnxWm, not Wd=WnxWm - Wi.
case AArch64::SUBSWri:
case AArch64::SUBSXri:
return true;
default:
break;
}
return false;
}
// 32b Opcodes that can be combined with a MUL
static bool isCombineInstrCandidate32(unsigned Opc) {
switch (Opc) {
case AArch64::ADDWrr:
case AArch64::ADDWri:
case AArch64::SUBWrr:
case AArch64::ADDSWrr:
case AArch64::ADDSWri:
case AArch64::SUBSWrr:
// Note: MSUB Wd,Wn,Wm,Wi -> Wd = Wi - WnxWm, not Wd=WnxWm - Wi.
case AArch64::SUBWri:
case AArch64::SUBSWri:
return true;
default:
break;
}
return false;
}
// 64b Opcodes that can be combined with a MUL
static bool isCombineInstrCandidate64(unsigned Opc) {
switch (Opc) {
case AArch64::ADDXrr:
case AArch64::ADDXri:
case AArch64::SUBXrr:
case AArch64::ADDSXrr:
case AArch64::ADDSXri:
case AArch64::SUBSXrr:
// Note: MSUB Wd,Wn,Wm,Wi -> Wd = Wi - WnxWm, not Wd=WnxWm - Wi.
case AArch64::SUBXri:
case AArch64::SUBSXri:
return true;
default:
break;
}
return false;
}
// FP Opcodes that can be combined with a FMUL
static bool isCombineInstrCandidateFP(const MachineInstr &Inst) {
switch (Inst.getOpcode()) {
default:
break;
case AArch64::FADDSrr:
case AArch64::FADDDrr:
case AArch64::FADDv2f32:
case AArch64::FADDv2f64:
case AArch64::FADDv4f32:
case AArch64::FSUBSrr:
case AArch64::FSUBDrr:
case AArch64::FSUBv2f32:
case AArch64::FSUBv2f64:
case AArch64::FSUBv4f32:
TargetOptions Options = Inst.getParent()->getParent()->getTarget().Options;
return (Options.UnsafeFPMath ||
Options.AllowFPOpFusion == FPOpFusion::Fast);
}
return false;
}
// Opcodes that can be combined with a MUL
static bool isCombineInstrCandidate(unsigned Opc) {
return (isCombineInstrCandidate32(Opc) || isCombineInstrCandidate64(Opc));
}
//
// Utility routine that checks if \param MO is defined by an
// \param CombineOpc instruction in the basic block \param MBB
static bool canCombine(MachineBasicBlock &MBB, MachineOperand &MO,
unsigned CombineOpc, unsigned ZeroReg = 0,
bool CheckZeroReg = false) {
MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
MachineInstr *MI = nullptr;
if (MO.isReg() && TargetRegisterInfo::isVirtualRegister(MO.getReg()))
MI = MRI.getUniqueVRegDef(MO.getReg());
// And it needs to be in the trace (otherwise, it won't have a depth).
if (!MI || MI->getParent() != &MBB || (unsigned)MI->getOpcode() != CombineOpc)
return false;
// Must only used by the user we combine with.
if (!MRI.hasOneNonDBGUse(MI->getOperand(0).getReg()))
return false;
if (CheckZeroReg) {
assert(MI->getNumOperands() >= 4 && MI->getOperand(0).isReg() &&
MI->getOperand(1).isReg() && MI->getOperand(2).isReg() &&
MI->getOperand(3).isReg() && "MAdd/MSub must have a least 4 regs");
// The third input reg must be zero.
if (MI->getOperand(3).getReg() != ZeroReg)
return false;
}
return true;
}
//
// Is \param MO defined by an integer multiply and can be combined?
static bool canCombineWithMUL(MachineBasicBlock &MBB, MachineOperand &MO,
unsigned MulOpc, unsigned ZeroReg) {
return canCombine(MBB, MO, MulOpc, ZeroReg, true);
}
//
// Is \param MO defined by a floating-point multiply and can be combined?
static bool canCombineWithFMUL(MachineBasicBlock &MBB, MachineOperand &MO,
unsigned MulOpc) {
return canCombine(MBB, MO, MulOpc);
}
// TODO: There are many more machine instruction opcodes to match:
// 1. Other data types (integer, vectors)
// 2. Other math / logic operations (xor, or)
// 3. Other forms of the same operation (intrinsics and other variants)
bool AArch64InstrInfo::isAssociativeAndCommutative(
const MachineInstr &Inst) const {
switch (Inst.getOpcode()) {
case AArch64::FADDDrr:
case AArch64::FADDSrr:
case AArch64::FADDv2f32:
case AArch64::FADDv2f64:
case AArch64::FADDv4f32:
case AArch64::FMULDrr:
case AArch64::FMULSrr:
case AArch64::FMULX32:
case AArch64::FMULX64:
case AArch64::FMULXv2f32:
case AArch64::FMULXv2f64:
case AArch64::FMULXv4f32:
case AArch64::FMULv2f32:
case AArch64::FMULv2f64:
case AArch64::FMULv4f32:
return Inst.getParent()->getParent()->getTarget().Options.UnsafeFPMath;
default:
return false;
}
}
/// Find instructions that can be turned into madd.
static bool getMaddPatterns(MachineInstr &Root,
SmallVectorImpl<MachineCombinerPattern> &Patterns) {
unsigned Opc = Root.getOpcode();
MachineBasicBlock &MBB = *Root.getParent();
bool Found = false;
if (!isCombineInstrCandidate(Opc))
return false;
if (isCombineInstrSettingFlag(Opc)) {
int Cmp_NZCV = Root.findRegisterDefOperandIdx(AArch64::NZCV, true);
// When NZCV is live bail out.
if (Cmp_NZCV == -1)
return false;
unsigned NewOpc = convertToNonFlagSettingOpc(Root);
// When opcode can't change bail out.
// CHECKME: do we miss any cases for opcode conversion?
if (NewOpc == Opc)
return false;
Opc = NewOpc;
}
switch (Opc) {
default:
break;
case AArch64::ADDWrr:
assert(Root.getOperand(1).isReg() && Root.getOperand(2).isReg() &&
"ADDWrr does not have register operands");
if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDWrrr,
AArch64::WZR)) {
Patterns.push_back(MachineCombinerPattern::MULADDW_OP1);
Found = true;
}
if (canCombineWithMUL(MBB, Root.getOperand(2), AArch64::MADDWrrr,
AArch64::WZR)) {
Patterns.push_back(MachineCombinerPattern::MULADDW_OP2);
Found = true;
}
break;
case AArch64::ADDXrr:
if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDXrrr,
AArch64::XZR)) {
Patterns.push_back(MachineCombinerPattern::MULADDX_OP1);
Found = true;
}
if (canCombineWithMUL(MBB, Root.getOperand(2), AArch64::MADDXrrr,
AArch64::XZR)) {
Patterns.push_back(MachineCombinerPattern::MULADDX_OP2);
Found = true;
}
break;
case AArch64::SUBWrr:
if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDWrrr,
AArch64::WZR)) {
Patterns.push_back(MachineCombinerPattern::MULSUBW_OP1);
Found = true;
}
if (canCombineWithMUL(MBB, Root.getOperand(2), AArch64::MADDWrrr,
AArch64::WZR)) {
Patterns.push_back(MachineCombinerPattern::MULSUBW_OP2);
Found = true;
}
break;
case AArch64::SUBXrr:
if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDXrrr,
AArch64::XZR)) {
Patterns.push_back(MachineCombinerPattern::MULSUBX_OP1);
Found = true;
}
if (canCombineWithMUL(MBB, Root.getOperand(2), AArch64::MADDXrrr,
AArch64::XZR)) {
Patterns.push_back(MachineCombinerPattern::MULSUBX_OP2);
Found = true;
}
break;
case AArch64::ADDWri:
if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDWrrr,
AArch64::WZR)) {
Patterns.push_back(MachineCombinerPattern::MULADDWI_OP1);
Found = true;
}
break;
case AArch64::ADDXri:
if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDXrrr,
AArch64::XZR)) {
Patterns.push_back(MachineCombinerPattern::MULADDXI_OP1);
Found = true;
}
break;
case AArch64::SUBWri:
if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDWrrr,
AArch64::WZR)) {
Patterns.push_back(MachineCombinerPattern::MULSUBWI_OP1);
Found = true;
}
break;
case AArch64::SUBXri:
if (canCombineWithMUL(MBB, Root.getOperand(1), AArch64::MADDXrrr,
AArch64::XZR)) {
Patterns.push_back(MachineCombinerPattern::MULSUBXI_OP1);
Found = true;
}
break;
}
return Found;
}
/// Floating-Point Support
/// Find instructions that can be turned into madd.
static bool getFMAPatterns(MachineInstr &Root,
SmallVectorImpl<MachineCombinerPattern> &Patterns) {
if (!isCombineInstrCandidateFP(Root))
return false;
MachineBasicBlock &MBB = *Root.getParent();
bool Found = false;
switch (Root.getOpcode()) {
default:
assert(false && "Unsupported FP instruction in combiner\n");
break;
case AArch64::FADDSrr:
assert(Root.getOperand(1).isReg() && Root.getOperand(2).isReg() &&
"FADDWrr does not have register operands");
if (canCombineWithFMUL(MBB, Root.getOperand(1), AArch64::FMULSrr)) {
Patterns.push_back(MachineCombinerPattern::FMULADDS_OP1);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv1i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLAv1i32_indexed_OP1);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(2), AArch64::FMULSrr)) {
Patterns.push_back(MachineCombinerPattern::FMULADDS_OP2);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv1i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLAv1i32_indexed_OP2);
Found = true;
}
break;
case AArch64::FADDDrr:
if (canCombineWithFMUL(MBB, Root.getOperand(1), AArch64::FMULDrr)) {
Patterns.push_back(MachineCombinerPattern::FMULADDD_OP1);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv1i64_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLAv1i64_indexed_OP1);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(2), AArch64::FMULDrr)) {
Patterns.push_back(MachineCombinerPattern::FMULADDD_OP2);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv1i64_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLAv1i64_indexed_OP2);
Found = true;
}
break;
case AArch64::FADDv2f32:
if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv2i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLAv2i32_indexed_OP1);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv2f32)) {
Patterns.push_back(MachineCombinerPattern::FMLAv2f32_OP1);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv2i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLAv2i32_indexed_OP2);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv2f32)) {
Patterns.push_back(MachineCombinerPattern::FMLAv2f32_OP2);
Found = true;
}
break;
case AArch64::FADDv2f64:
if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv2i64_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLAv2i64_indexed_OP1);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv2f64)) {
Patterns.push_back(MachineCombinerPattern::FMLAv2f64_OP1);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv2i64_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLAv2i64_indexed_OP2);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv2f64)) {
Patterns.push_back(MachineCombinerPattern::FMLAv2f64_OP2);
Found = true;
}
break;
case AArch64::FADDv4f32:
if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv4i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLAv4i32_indexed_OP1);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv4f32)) {
Patterns.push_back(MachineCombinerPattern::FMLAv4f32_OP1);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv4i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLAv4i32_indexed_OP2);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv4f32)) {
Patterns.push_back(MachineCombinerPattern::FMLAv4f32_OP2);
Found = true;
}
break;
case AArch64::FSUBSrr:
if (canCombineWithFMUL(MBB, Root.getOperand(1), AArch64::FMULSrr)) {
Patterns.push_back(MachineCombinerPattern::FMULSUBS_OP1);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(2), AArch64::FMULSrr)) {
Patterns.push_back(MachineCombinerPattern::FMULSUBS_OP2);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv1i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLSv1i32_indexed_OP2);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(1), AArch64::FNMULSrr)) {
Patterns.push_back(MachineCombinerPattern::FNMULSUBS_OP1);
Found = true;
}
break;
case AArch64::FSUBDrr:
if (canCombineWithFMUL(MBB, Root.getOperand(1), AArch64::FMULDrr)) {
Patterns.push_back(MachineCombinerPattern::FMULSUBD_OP1);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(2), AArch64::FMULDrr)) {
Patterns.push_back(MachineCombinerPattern::FMULSUBD_OP2);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv1i64_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLSv1i64_indexed_OP2);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(1), AArch64::FNMULDrr)) {
Patterns.push_back(MachineCombinerPattern::FNMULSUBD_OP1);
Found = true;
}
break;
case AArch64::FSUBv2f32:
if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv2i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLSv2i32_indexed_OP2);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv2f32)) {
Patterns.push_back(MachineCombinerPattern::FMLSv2f32_OP2);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv2i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLSv2i32_indexed_OP1);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv2f32)) {
Patterns.push_back(MachineCombinerPattern::FMLSv2f32_OP1);
Found = true;
}
break;
case AArch64::FSUBv2f64:
if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv2i64_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLSv2i64_indexed_OP2);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv2f64)) {
Patterns.push_back(MachineCombinerPattern::FMLSv2f64_OP2);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv2i64_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLSv2i64_indexed_OP1);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv2f64)) {
Patterns.push_back(MachineCombinerPattern::FMLSv2f64_OP1);
Found = true;
}
break;
case AArch64::FSUBv4f32:
if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv4i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLSv4i32_indexed_OP2);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(2),
AArch64::FMULv4f32)) {
Patterns.push_back(MachineCombinerPattern::FMLSv4f32_OP2);
Found = true;
}
if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv4i32_indexed)) {
Patterns.push_back(MachineCombinerPattern::FMLSv4i32_indexed_OP1);
Found = true;
} else if (canCombineWithFMUL(MBB, Root.getOperand(1),
AArch64::FMULv4f32)) {
Patterns.push_back(MachineCombinerPattern::FMLSv4f32_OP1);
Found = true;
}
break;
}
return Found;
}
/// Return true when a code sequence can improve throughput. It
/// should be called only for instructions in loops.
/// \param Pattern - combiner pattern
bool AArch64InstrInfo::isThroughputPattern(
MachineCombinerPattern Pattern) const {
switch (Pattern) {
default:
break;
case MachineCombinerPattern::FMULADDS_OP1:
case MachineCombinerPattern::FMULADDS_OP2:
case MachineCombinerPattern::FMULSUBS_OP1:
case MachineCombinerPattern::FMULSUBS_OP2:
case MachineCombinerPattern::FMULADDD_OP1:
case MachineCombinerPattern::FMULADDD_OP2:
case MachineCombinerPattern::FMULSUBD_OP1:
case MachineCombinerPattern::FMULSUBD_OP2:
case MachineCombinerPattern::FNMULSUBS_OP1:
case MachineCombinerPattern::FNMULSUBD_OP1:
case MachineCombinerPattern::FMLAv1i32_indexed_OP1:
case MachineCombinerPattern::FMLAv1i32_indexed_OP2:
case MachineCombinerPattern::FMLAv1i64_indexed_OP1:
case MachineCombinerPattern::FMLAv1i64_indexed_OP2:
case MachineCombinerPattern::FMLAv2f32_OP2:
case MachineCombinerPattern::FMLAv2f32_OP1:
case MachineCombinerPattern::FMLAv2f64_OP1:
case MachineCombinerPattern::FMLAv2f64_OP2:
case MachineCombinerPattern::FMLAv2i32_indexed_OP1:
case MachineCombinerPattern::FMLAv2i32_indexed_OP2:
case MachineCombinerPattern::FMLAv2i64_indexed_OP1:
case MachineCombinerPattern::FMLAv2i64_indexed_OP2:
case MachineCombinerPattern::FMLAv4f32_OP1:
case MachineCombinerPattern::FMLAv4f32_OP2:
case MachineCombinerPattern::FMLAv4i32_indexed_OP1:
case MachineCombinerPattern::FMLAv4i32_indexed_OP2:
case MachineCombinerPattern::FMLSv1i32_indexed_OP2:
case MachineCombinerPattern::FMLSv1i64_indexed_OP2:
case MachineCombinerPattern::FMLSv2i32_indexed_OP2:
case MachineCombinerPattern::FMLSv2i64_indexed_OP2:
case MachineCombinerPattern::FMLSv2f32_OP2:
case MachineCombinerPattern::FMLSv2f64_OP2:
case MachineCombinerPattern::FMLSv4i32_indexed_OP2:
case MachineCombinerPattern::FMLSv4f32_OP2:
return true;
} // end switch (Pattern)
return false;
}
/// Return true when there is potentially a faster code sequence for an
/// instruction chain ending in \p Root. All potential patterns are listed in
/// the \p Pattern vector. Pattern should be sorted in priority order since the
/// pattern evaluator stops checking as soon as it finds a faster sequence.
bool AArch64InstrInfo::getMachineCombinerPatterns(
MachineInstr &Root,
SmallVectorImpl<MachineCombinerPattern> &Patterns) const {
// Integer patterns
if (getMaddPatterns(Root, Patterns))
return true;
// Floating point patterns
if (getFMAPatterns(Root, Patterns))
return true;
return TargetInstrInfo::getMachineCombinerPatterns(Root, Patterns);
}
enum class FMAInstKind { Default, Indexed, Accumulator };
/// genFusedMultiply - Generate fused multiply instructions.
/// This function supports both integer and floating point instructions.
/// A typical example:
/// F|MUL I=A,B,0
/// F|ADD R,I,C
/// ==> F|MADD R,A,B,C
/// \param MF Containing MachineFunction
/// \param MRI Register information
/// \param TII Target information
/// \param Root is the F|ADD instruction
/// \param [out] InsInstrs is a vector of machine instructions and will
/// contain the generated madd instruction
/// \param IdxMulOpd is index of operand in Root that is the result of
/// the F|MUL. In the example above IdxMulOpd is 1.
/// \param MaddOpc the opcode fo the f|madd instruction
/// \param RC Register class of operands
/// \param kind of fma instruction (addressing mode) to be generated
/// \param ReplacedAddend is the result register from the instruction
/// replacing the non-combined operand, if any.
static MachineInstr *
genFusedMultiply(MachineFunction &MF, MachineRegisterInfo &MRI,
const TargetInstrInfo *TII, MachineInstr &Root,
SmallVectorImpl<MachineInstr *> &InsInstrs, unsigned IdxMulOpd,
unsigned MaddOpc, const TargetRegisterClass *RC,
FMAInstKind kind = FMAInstKind::Default,
const unsigned *ReplacedAddend = nullptr) {
assert(IdxMulOpd == 1 || IdxMulOpd == 2);
unsigned IdxOtherOpd = IdxMulOpd == 1 ? 2 : 1;
MachineInstr *MUL = MRI.getUniqueVRegDef(Root.getOperand(IdxMulOpd).getReg());
unsigned ResultReg = Root.getOperand(0).getReg();
unsigned SrcReg0 = MUL->getOperand(1).getReg();
bool Src0IsKill = MUL->getOperand(1).isKill();
unsigned SrcReg1 = MUL->getOperand(2).getReg();
bool Src1IsKill = MUL->getOperand(2).isKill();
unsigned SrcReg2;
bool Src2IsKill;
if (ReplacedAddend) {
// If we just generated a new addend, we must be it's only use.
SrcReg2 = *ReplacedAddend;
Src2IsKill = true;
} else {
SrcReg2 = Root.getOperand(IdxOtherOpd).getReg();
Src2IsKill = Root.getOperand(IdxOtherOpd).isKill();
}
if (TargetRegisterInfo::isVirtualRegister(ResultReg))
MRI.constrainRegClass(ResultReg, RC);
if (TargetRegisterInfo::isVirtualRegister(SrcReg0))
MRI.constrainRegClass(SrcReg0, RC);
if (TargetRegisterInfo::isVirtualRegister(SrcReg1))
MRI.constrainRegClass(SrcReg1, RC);
if (TargetRegisterInfo::isVirtualRegister(SrcReg2))
MRI.constrainRegClass(SrcReg2, RC);
MachineInstrBuilder MIB;
if (kind == FMAInstKind::Default)
MIB = BuildMI(MF, Root.getDebugLoc(), TII->get(MaddOpc), ResultReg)
.addReg(SrcReg0, getKillRegState(Src0IsKill))
.addReg(SrcReg1, getKillRegState(Src1IsKill))
.addReg(SrcReg2, getKillRegState(Src2IsKill));
else if (kind == FMAInstKind::Indexed)
MIB = BuildMI(MF, Root.getDebugLoc(), TII->get(MaddOpc), ResultReg)
.addReg(SrcReg2, getKillRegState(Src2IsKill))
.addReg(SrcReg0, getKillRegState(Src0IsKill))
.addReg(SrcReg1, getKillRegState(Src1IsKill))
.addImm(MUL->getOperand(3).getImm());
else if (kind == FMAInstKind::Accumulator)
MIB = BuildMI(MF, Root.getDebugLoc(), TII->get(MaddOpc), ResultReg)
.addReg(SrcReg2, getKillRegState(Src2IsKill))
.addReg(SrcReg0, getKillRegState(Src0IsKill))
.addReg(SrcReg1, getKillRegState(Src1IsKill));
else
assert(false && "Invalid FMA instruction kind \n");
// Insert the MADD (MADD, FMA, FMS, FMLA, FMSL)
InsInstrs.push_back(MIB);
return MUL;
}
/// genMaddR - Generate madd instruction and combine mul and add using
/// an extra virtual register
/// Example - an ADD intermediate needs to be stored in a register:
/// MUL I=A,B,0
/// ADD R,I,Imm
/// ==> ORR V, ZR, Imm
/// ==> MADD R,A,B,V
/// \param MF Containing MachineFunction
/// \param MRI Register information
/// \param TII Target information
/// \param Root is the ADD instruction
/// \param [out] InsInstrs is a vector of machine instructions and will
/// contain the generated madd instruction
/// \param IdxMulOpd is index of operand in Root that is the result of
/// the MUL. In the example above IdxMulOpd is 1.
/// \param MaddOpc the opcode fo the madd instruction
/// \param VR is a virtual register that holds the value of an ADD operand
/// (V in the example above).
/// \param RC Register class of operands
static MachineInstr *genMaddR(MachineFunction &MF, MachineRegisterInfo &MRI,
const TargetInstrInfo *TII, MachineInstr &Root,
SmallVectorImpl<MachineInstr *> &InsInstrs,
unsigned IdxMulOpd, unsigned MaddOpc, unsigned VR,
const TargetRegisterClass *RC) {
assert(IdxMulOpd == 1 || IdxMulOpd == 2);
MachineInstr *MUL = MRI.getUniqueVRegDef(Root.getOperand(IdxMulOpd).getReg());
unsigned ResultReg = Root.getOperand(0).getReg();
unsigned SrcReg0 = MUL->getOperand(1).getReg();
bool Src0IsKill = MUL->getOperand(1).isKill();
unsigned SrcReg1 = MUL->getOperand(2).getReg();
bool Src1IsKill = MUL->getOperand(2).isKill();
if (TargetRegisterInfo::isVirtualRegister(ResultReg))
MRI.constrainRegClass(ResultReg, RC);
if (TargetRegisterInfo::isVirtualRegister(SrcReg0))
MRI.constrainRegClass(SrcReg0, RC);
if (TargetRegisterInfo::isVirtualRegister(SrcReg1))
MRI.constrainRegClass(SrcReg1, RC);
if (TargetRegisterInfo::isVirtualRegister(VR))
MRI.constrainRegClass(VR, RC);
MachineInstrBuilder MIB =
BuildMI(MF, Root.getDebugLoc(), TII->get(MaddOpc), ResultReg)
.addReg(SrcReg0, getKillRegState(Src0IsKill))
.addReg(SrcReg1, getKillRegState(Src1IsKill))
.addReg(VR);
// Insert the MADD
InsInstrs.push_back(MIB);
return MUL;
}
/// When getMachineCombinerPatterns() finds potential patterns,
/// this function generates the instructions that could replace the
/// original code sequence
void AArch64InstrInfo::genAlternativeCodeSequence(
MachineInstr &Root, MachineCombinerPattern Pattern,
SmallVectorImpl<MachineInstr *> &InsInstrs,
SmallVectorImpl<MachineInstr *> &DelInstrs,
DenseMap<unsigned, unsigned> &InstrIdxForVirtReg) const {
MachineBasicBlock &MBB = *Root.getParent();
MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
MachineFunction &MF = *MBB.getParent();
const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
MachineInstr *MUL;
const TargetRegisterClass *RC;
unsigned Opc;
switch (Pattern) {
default:
// Reassociate instructions.
TargetInstrInfo::genAlternativeCodeSequence(Root, Pattern, InsInstrs,
DelInstrs, InstrIdxForVirtReg);
return;
case MachineCombinerPattern::MULADDW_OP1:
case MachineCombinerPattern::MULADDX_OP1:
// MUL I=A,B,0
// ADD R,I,C
// ==> MADD R,A,B,C
// --- Create(MADD);
if (Pattern == MachineCombinerPattern::MULADDW_OP1) {
Opc = AArch64::MADDWrrr;
RC = &AArch64::GPR32RegClass;
} else {
Opc = AArch64::MADDXrrr;
RC = &AArch64::GPR64RegClass;
}
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC);
break;
case MachineCombinerPattern::MULADDW_OP2:
case MachineCombinerPattern::MULADDX_OP2:
// MUL I=A,B,0
// ADD R,C,I
// ==> MADD R,A,B,C
// --- Create(MADD);
if (Pattern == MachineCombinerPattern::MULADDW_OP2) {
Opc = AArch64::MADDWrrr;
RC = &AArch64::GPR32RegClass;
} else {
Opc = AArch64::MADDXrrr;
RC = &AArch64::GPR64RegClass;
}
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC);
break;
case MachineCombinerPattern::MULADDWI_OP1:
case MachineCombinerPattern::MULADDXI_OP1: {
// MUL I=A,B,0
// ADD R,I,Imm
// ==> ORR V, ZR, Imm
// ==> MADD R,A,B,V
// --- Create(MADD);
const TargetRegisterClass *OrrRC;
unsigned BitSize, OrrOpc, ZeroReg;
if (Pattern == MachineCombinerPattern::MULADDWI_OP1) {
OrrOpc = AArch64::ORRWri;
OrrRC = &AArch64::GPR32spRegClass;
BitSize = 32;
ZeroReg = AArch64::WZR;
Opc = AArch64::MADDWrrr;
RC = &AArch64::GPR32RegClass;
} else {
OrrOpc = AArch64::ORRXri;
OrrRC = &AArch64::GPR64spRegClass;
BitSize = 64;
ZeroReg = AArch64::XZR;
Opc = AArch64::MADDXrrr;
RC = &AArch64::GPR64RegClass;
}
unsigned NewVR = MRI.createVirtualRegister(OrrRC);
uint64_t Imm = Root.getOperand(2).getImm();
if (Root.getOperand(3).isImm()) {
unsigned Val = Root.getOperand(3).getImm();
Imm = Imm << Val;
}
uint64_t UImm = SignExtend64(Imm, BitSize);
uint64_t Encoding;
if (AArch64_AM::processLogicalImmediate(UImm, BitSize, Encoding)) {
MachineInstrBuilder MIB1 =
BuildMI(MF, Root.getDebugLoc(), TII->get(OrrOpc), NewVR)
.addReg(ZeroReg)
.addImm(Encoding);
InsInstrs.push_back(MIB1);
InstrIdxForVirtReg.insert(std::make_pair(NewVR, 0));
MUL = genMaddR(MF, MRI, TII, Root, InsInstrs, 1, Opc, NewVR, RC);
}
break;
}
case MachineCombinerPattern::MULSUBW_OP1:
case MachineCombinerPattern::MULSUBX_OP1: {
// MUL I=A,B,0
// SUB R,I, C
// ==> SUB V, 0, C
// ==> MADD R,A,B,V // = -C + A*B
// --- Create(MADD);
const TargetRegisterClass *SubRC;
unsigned SubOpc, ZeroReg;
if (Pattern == MachineCombinerPattern::MULSUBW_OP1) {
SubOpc = AArch64::SUBWrr;
SubRC = &AArch64::GPR32spRegClass;
ZeroReg = AArch64::WZR;
Opc = AArch64::MADDWrrr;
RC = &AArch64::GPR32RegClass;
} else {
SubOpc = AArch64::SUBXrr;
SubRC = &AArch64::GPR64spRegClass;
ZeroReg = AArch64::XZR;
Opc = AArch64::MADDXrrr;
RC = &AArch64::GPR64RegClass;
}
unsigned NewVR = MRI.createVirtualRegister(SubRC);
// SUB NewVR, 0, C
MachineInstrBuilder MIB1 =
BuildMI(MF, Root.getDebugLoc(), TII->get(SubOpc), NewVR)
.addReg(ZeroReg)
.add(Root.getOperand(2));
InsInstrs.push_back(MIB1);
InstrIdxForVirtReg.insert(std::make_pair(NewVR, 0));
MUL = genMaddR(MF, MRI, TII, Root, InsInstrs, 1, Opc, NewVR, RC);
break;
}
case MachineCombinerPattern::MULSUBW_OP2:
case MachineCombinerPattern::MULSUBX_OP2:
// MUL I=A,B,0
// SUB R,C,I
// ==> MSUB R,A,B,C (computes C - A*B)
// --- Create(MSUB);
if (Pattern == MachineCombinerPattern::MULSUBW_OP2) {
Opc = AArch64::MSUBWrrr;
RC = &AArch64::GPR32RegClass;
} else {
Opc = AArch64::MSUBXrrr;
RC = &AArch64::GPR64RegClass;
}
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC);
break;
case MachineCombinerPattern::MULSUBWI_OP1:
case MachineCombinerPattern::MULSUBXI_OP1: {
// MUL I=A,B,0
// SUB R,I, Imm
// ==> ORR V, ZR, -Imm
// ==> MADD R,A,B,V // = -Imm + A*B
// --- Create(MADD);
const TargetRegisterClass *OrrRC;
unsigned BitSize, OrrOpc, ZeroReg;
if (Pattern == MachineCombinerPattern::MULSUBWI_OP1) {
OrrOpc = AArch64::ORRWri;
OrrRC = &AArch64::GPR32spRegClass;
BitSize = 32;
ZeroReg = AArch64::WZR;
Opc = AArch64::MADDWrrr;
RC = &AArch64::GPR32RegClass;
} else {
OrrOpc = AArch64::ORRXri;
OrrRC = &AArch64::GPR64spRegClass;
BitSize = 64;
ZeroReg = AArch64::XZR;
Opc = AArch64::MADDXrrr;
RC = &AArch64::GPR64RegClass;
}
unsigned NewVR = MRI.createVirtualRegister(OrrRC);
uint64_t Imm = Root.getOperand(2).getImm();
if (Root.getOperand(3).isImm()) {
unsigned Val = Root.getOperand(3).getImm();
Imm = Imm << Val;
}
uint64_t UImm = SignExtend64(-Imm, BitSize);
uint64_t Encoding;
if (AArch64_AM::processLogicalImmediate(UImm, BitSize, Encoding)) {
MachineInstrBuilder MIB1 =
BuildMI(MF, Root.getDebugLoc(), TII->get(OrrOpc), NewVR)
.addReg(ZeroReg)
.addImm(Encoding);
InsInstrs.push_back(MIB1);
InstrIdxForVirtReg.insert(std::make_pair(NewVR, 0));
MUL = genMaddR(MF, MRI, TII, Root, InsInstrs, 1, Opc, NewVR, RC);
}
break;
}
// Floating Point Support
case MachineCombinerPattern::FMULADDS_OP1:
case MachineCombinerPattern::FMULADDD_OP1:
// MUL I=A,B,0
// ADD R,I,C
// ==> MADD R,A,B,C
// --- Create(MADD);
if (Pattern == MachineCombinerPattern::FMULADDS_OP1) {
Opc = AArch64::FMADDSrrr;
RC = &AArch64::FPR32RegClass;
} else {
Opc = AArch64::FMADDDrrr;
RC = &AArch64::FPR64RegClass;
}
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC);
break;
case MachineCombinerPattern::FMULADDS_OP2:
case MachineCombinerPattern::FMULADDD_OP2:
// FMUL I=A,B,0
// FADD R,C,I
// ==> FMADD R,A,B,C
// --- Create(FMADD);
if (Pattern == MachineCombinerPattern::FMULADDS_OP2) {
Opc = AArch64::FMADDSrrr;
RC = &AArch64::FPR32RegClass;
} else {
Opc = AArch64::FMADDDrrr;
RC = &AArch64::FPR64RegClass;
}
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC);
break;
case MachineCombinerPattern::FMLAv1i32_indexed_OP1:
Opc = AArch64::FMLAv1i32_indexed;
RC = &AArch64::FPR32RegClass;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Indexed);
break;
case MachineCombinerPattern::FMLAv1i32_indexed_OP2:
Opc = AArch64::FMLAv1i32_indexed;
RC = &AArch64::FPR32RegClass;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Indexed);
break;
case MachineCombinerPattern::FMLAv1i64_indexed_OP1:
Opc = AArch64::FMLAv1i64_indexed;
RC = &AArch64::FPR64RegClass;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Indexed);
break;
case MachineCombinerPattern::FMLAv1i64_indexed_OP2:
Opc = AArch64::FMLAv1i64_indexed;
RC = &AArch64::FPR64RegClass;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Indexed);
break;
case MachineCombinerPattern::FMLAv2i32_indexed_OP1:
case MachineCombinerPattern::FMLAv2f32_OP1:
RC = &AArch64::FPR64RegClass;
if (Pattern == MachineCombinerPattern::FMLAv2i32_indexed_OP1) {
Opc = AArch64::FMLAv2i32_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Indexed);
} else {
Opc = AArch64::FMLAv2f32;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Accumulator);
}
break;
case MachineCombinerPattern::FMLAv2i32_indexed_OP2:
case MachineCombinerPattern::FMLAv2f32_OP2:
RC = &AArch64::FPR64RegClass;
if (Pattern == MachineCombinerPattern::FMLAv2i32_indexed_OP2) {
Opc = AArch64::FMLAv2i32_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Indexed);
} else {
Opc = AArch64::FMLAv2f32;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Accumulator);
}
break;
case MachineCombinerPattern::FMLAv2i64_indexed_OP1:
case MachineCombinerPattern::FMLAv2f64_OP1:
RC = &AArch64::FPR128RegClass;
if (Pattern == MachineCombinerPattern::FMLAv2i64_indexed_OP1) {
Opc = AArch64::FMLAv2i64_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Indexed);
} else {
Opc = AArch64::FMLAv2f64;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Accumulator);
}
break;
case MachineCombinerPattern::FMLAv2i64_indexed_OP2:
case MachineCombinerPattern::FMLAv2f64_OP2:
RC = &AArch64::FPR128RegClass;
if (Pattern == MachineCombinerPattern::FMLAv2i64_indexed_OP2) {
Opc = AArch64::FMLAv2i64_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Indexed);
} else {
Opc = AArch64::FMLAv2f64;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Accumulator);
}
break;
case MachineCombinerPattern::FMLAv4i32_indexed_OP1:
case MachineCombinerPattern::FMLAv4f32_OP1:
RC = &AArch64::FPR128RegClass;
if (Pattern == MachineCombinerPattern::FMLAv4i32_indexed_OP1) {
Opc = AArch64::FMLAv4i32_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Indexed);
} else {
Opc = AArch64::FMLAv4f32;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Accumulator);
}
break;
case MachineCombinerPattern::FMLAv4i32_indexed_OP2:
case MachineCombinerPattern::FMLAv4f32_OP2:
RC = &AArch64::FPR128RegClass;
if (Pattern == MachineCombinerPattern::FMLAv4i32_indexed_OP2) {
Opc = AArch64::FMLAv4i32_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Indexed);
} else {
Opc = AArch64::FMLAv4f32;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Accumulator);
}
break;
case MachineCombinerPattern::FMULSUBS_OP1:
case MachineCombinerPattern::FMULSUBD_OP1: {
// FMUL I=A,B,0
// FSUB R,I,C
// ==> FNMSUB R,A,B,C // = -C + A*B
// --- Create(FNMSUB);
if (Pattern == MachineCombinerPattern::FMULSUBS_OP1) {
Opc = AArch64::FNMSUBSrrr;
RC = &AArch64::FPR32RegClass;
} else {
Opc = AArch64::FNMSUBDrrr;
RC = &AArch64::FPR64RegClass;
}
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC);
break;
}
case MachineCombinerPattern::FNMULSUBS_OP1:
case MachineCombinerPattern::FNMULSUBD_OP1: {
// FNMUL I=A,B,0
// FSUB R,I,C
// ==> FNMADD R,A,B,C // = -A*B - C
// --- Create(FNMADD);
if (Pattern == MachineCombinerPattern::FNMULSUBS_OP1) {
Opc = AArch64::FNMADDSrrr;
RC = &AArch64::FPR32RegClass;
} else {
Opc = AArch64::FNMADDDrrr;
RC = &AArch64::FPR64RegClass;
}
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC);
break;
}
case MachineCombinerPattern::FMULSUBS_OP2:
case MachineCombinerPattern::FMULSUBD_OP2: {
// FMUL I=A,B,0
// FSUB R,C,I
// ==> FMSUB R,A,B,C (computes C - A*B)
// --- Create(FMSUB);
if (Pattern == MachineCombinerPattern::FMULSUBS_OP2) {
Opc = AArch64::FMSUBSrrr;
RC = &AArch64::FPR32RegClass;
} else {
Opc = AArch64::FMSUBDrrr;
RC = &AArch64::FPR64RegClass;
}
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC);
break;
}
case MachineCombinerPattern::FMLSv1i32_indexed_OP2:
Opc = AArch64::FMLSv1i32_indexed;
RC = &AArch64::FPR32RegClass;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Indexed);
break;
case MachineCombinerPattern::FMLSv1i64_indexed_OP2:
Opc = AArch64::FMLSv1i64_indexed;
RC = &AArch64::FPR64RegClass;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Indexed);
break;
case MachineCombinerPattern::FMLSv2f32_OP2:
case MachineCombinerPattern::FMLSv2i32_indexed_OP2:
RC = &AArch64::FPR64RegClass;
if (Pattern == MachineCombinerPattern::FMLSv2i32_indexed_OP2) {
Opc = AArch64::FMLSv2i32_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Indexed);
} else {
Opc = AArch64::FMLSv2f32;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Accumulator);
}
break;
case MachineCombinerPattern::FMLSv2f64_OP2:
case MachineCombinerPattern::FMLSv2i64_indexed_OP2:
RC = &AArch64::FPR128RegClass;
if (Pattern == MachineCombinerPattern::FMLSv2i64_indexed_OP2) {
Opc = AArch64::FMLSv2i64_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Indexed);
} else {
Opc = AArch64::FMLSv2f64;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Accumulator);
}
break;
case MachineCombinerPattern::FMLSv4f32_OP2:
case MachineCombinerPattern::FMLSv4i32_indexed_OP2:
RC = &AArch64::FPR128RegClass;
if (Pattern == MachineCombinerPattern::FMLSv4i32_indexed_OP2) {
Opc = AArch64::FMLSv4i32_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Indexed);
} else {
Opc = AArch64::FMLSv4f32;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 2, Opc, RC,
FMAInstKind::Accumulator);
}
break;
case MachineCombinerPattern::FMLSv2f32_OP1:
case MachineCombinerPattern::FMLSv2i32_indexed_OP1: {
RC = &AArch64::FPR64RegClass;
unsigned NewVR = MRI.createVirtualRegister(RC);
MachineInstrBuilder MIB1 =
BuildMI(MF, Root.getDebugLoc(), TII->get(AArch64::FNEGv2f32), NewVR)
.add(Root.getOperand(2));
InsInstrs.push_back(MIB1);
InstrIdxForVirtReg.insert(std::make_pair(NewVR, 0));
if (Pattern == MachineCombinerPattern::FMLSv2i32_indexed_OP1) {
Opc = AArch64::FMLAv2i32_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Indexed, &NewVR);
} else {
Opc = AArch64::FMLAv2f32;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Accumulator, &NewVR);
}
break;
}
case MachineCombinerPattern::FMLSv4f32_OP1:
case MachineCombinerPattern::FMLSv4i32_indexed_OP1: {
RC = &AArch64::FPR128RegClass;
unsigned NewVR = MRI.createVirtualRegister(RC);
MachineInstrBuilder MIB1 =
BuildMI(MF, Root.getDebugLoc(), TII->get(AArch64::FNEGv4f32), NewVR)
.add(Root.getOperand(2));
InsInstrs.push_back(MIB1);
InstrIdxForVirtReg.insert(std::make_pair(NewVR, 0));
if (Pattern == MachineCombinerPattern::FMLSv4i32_indexed_OP1) {
Opc = AArch64::FMLAv4i32_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Indexed, &NewVR);
} else {
Opc = AArch64::FMLAv4f32;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Accumulator, &NewVR);
}
break;
}
case MachineCombinerPattern::FMLSv2f64_OP1:
case MachineCombinerPattern::FMLSv2i64_indexed_OP1: {
RC = &AArch64::FPR128RegClass;
unsigned NewVR = MRI.createVirtualRegister(RC);
MachineInstrBuilder MIB1 =
BuildMI(MF, Root.getDebugLoc(), TII->get(AArch64::FNEGv2f64), NewVR)
.add(Root.getOperand(2));
InsInstrs.push_back(MIB1);
InstrIdxForVirtReg.insert(std::make_pair(NewVR, 0));
if (Pattern == MachineCombinerPattern::FMLSv2i64_indexed_OP1) {
Opc = AArch64::FMLAv2i64_indexed;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Indexed, &NewVR);
} else {
Opc = AArch64::FMLAv2f64;
MUL = genFusedMultiply(MF, MRI, TII, Root, InsInstrs, 1, Opc, RC,
FMAInstKind::Accumulator, &NewVR);
}
break;
}
} // end switch (Pattern)
// Record MUL and ADD/SUB for deletion
DelInstrs.push_back(MUL);
DelInstrs.push_back(&Root);
}
/// Replace csincr-branch sequence by simple conditional branch
///
/// Examples:
/// 1. \code
/// csinc w9, wzr, wzr, <condition code>
/// tbnz w9, #0, 0x44
/// \endcode
/// to
/// \code
/// b.<inverted condition code>
/// \endcode
///
/// 2. \code
/// csinc w9, wzr, wzr, <condition code>
/// tbz w9, #0, 0x44
/// \endcode
/// to
/// \code
/// b.<condition code>
/// \endcode
///
/// Replace compare and branch sequence by TBZ/TBNZ instruction when the
/// compare's constant operand is power of 2.
///
/// Examples:
/// \code
/// and w8, w8, #0x400
/// cbnz w8, L1
/// \endcode
/// to
/// \code
/// tbnz w8, #10, L1
/// \endcode
///
/// \param MI Conditional Branch
/// \return True when the simple conditional branch is generated
///
bool AArch64InstrInfo::optimizeCondBranch(MachineInstr &MI) const {
bool IsNegativeBranch = false;
bool IsTestAndBranch = false;
unsigned TargetBBInMI = 0;
switch (MI.getOpcode()) {
default:
llvm_unreachable("Unknown branch instruction?");
case AArch64::Bcc:
return false;
case AArch64::CBZW:
case AArch64::CBZX:
TargetBBInMI = 1;
break;
case AArch64::CBNZW:
case AArch64::CBNZX:
TargetBBInMI = 1;
IsNegativeBranch = true;
break;
case AArch64::TBZW:
case AArch64::TBZX:
TargetBBInMI = 2;
IsTestAndBranch = true;
break;
case AArch64::TBNZW:
case AArch64::TBNZX:
TargetBBInMI = 2;
IsNegativeBranch = true;
IsTestAndBranch = true;
break;
}
// So we increment a zero register and test for bits other
// than bit 0? Conservatively bail out in case the verifier
// missed this case.
if (IsTestAndBranch && MI.getOperand(1).getImm())
return false;
// Find Definition.
assert(MI.getParent() && "Incomplete machine instruciton\n");
MachineBasicBlock *MBB = MI.getParent();
MachineFunction *MF = MBB->getParent();
MachineRegisterInfo *MRI = &MF->getRegInfo();
unsigned VReg = MI.getOperand(0).getReg();
if (!TargetRegisterInfo::isVirtualRegister(VReg))
return false;
MachineInstr *DefMI = MRI->getVRegDef(VReg);
// Look through COPY instructions to find definition.
while (DefMI->isCopy()) {
unsigned CopyVReg = DefMI->getOperand(1).getReg();
if (!MRI->hasOneNonDBGUse(CopyVReg))
return false;
if (!MRI->hasOneDef(CopyVReg))
return false;
DefMI = MRI->getVRegDef(CopyVReg);
}
switch (DefMI->getOpcode()) {
default:
return false;
// Fold AND into a TBZ/TBNZ if constant operand is power of 2.
case AArch64::ANDWri:
case AArch64::ANDXri: {
if (IsTestAndBranch)
return false;
if (DefMI->getParent() != MBB)
return false;
if (!MRI->hasOneNonDBGUse(VReg))
return false;
bool Is32Bit = (DefMI->getOpcode() == AArch64::ANDWri);
uint64_t Mask = AArch64_AM::decodeLogicalImmediate(
DefMI->getOperand(2).getImm(), Is32Bit ? 32 : 64);
if (!isPowerOf2_64(Mask))
return false;
MachineOperand &MO = DefMI->getOperand(1);
unsigned NewReg = MO.getReg();
if (!TargetRegisterInfo::isVirtualRegister(NewReg))
return false;
assert(!MRI->def_empty(NewReg) && "Register must be defined.");
MachineBasicBlock &RefToMBB = *MBB;
MachineBasicBlock *TBB = MI.getOperand(1).getMBB();
DebugLoc DL = MI.getDebugLoc();
unsigned Imm = Log2_64(Mask);
unsigned Opc = (Imm < 32)
? (IsNegativeBranch ? AArch64::TBNZW : AArch64::TBZW)
: (IsNegativeBranch ? AArch64::TBNZX : AArch64::TBZX);
MachineInstr *NewMI = BuildMI(RefToMBB, MI, DL, get(Opc))
.addReg(NewReg)
.addImm(Imm)
.addMBB(TBB);
// Register lives on to the CBZ now.
MO.setIsKill(false);
// For immediate smaller than 32, we need to use the 32-bit
// variant (W) in all cases. Indeed the 64-bit variant does not
// allow to encode them.
// Therefore, if the input register is 64-bit, we need to take the
// 32-bit sub-part.
if (!Is32Bit && Imm < 32)
NewMI->getOperand(0).setSubReg(AArch64::sub_32);
MI.eraseFromParent();
return true;
}
// Look for CSINC
case AArch64::CSINCWr:
case AArch64::CSINCXr: {
if (!(DefMI->getOperand(1).getReg() == AArch64::WZR &&
DefMI->getOperand(2).getReg() == AArch64::WZR) &&
!(DefMI->getOperand(1).getReg() == AArch64::XZR &&
DefMI->getOperand(2).getReg() == AArch64::XZR))
return false;
if (DefMI->findRegisterDefOperandIdx(AArch64::NZCV, true) != -1)
return false;
AArch64CC::CondCode CC = (AArch64CC::CondCode)DefMI->getOperand(3).getImm();
// Convert only when the condition code is not modified between
// the CSINC and the branch. The CC may be used by other
// instructions in between.
if (areCFlagsAccessedBetweenInstrs(DefMI, MI, &getRegisterInfo(), AK_Write))
return false;
MachineBasicBlock &RefToMBB = *MBB;
MachineBasicBlock *TBB = MI.getOperand(TargetBBInMI).getMBB();
DebugLoc DL = MI.getDebugLoc();
if (IsNegativeBranch)
CC = AArch64CC::getInvertedCondCode(CC);
BuildMI(RefToMBB, MI, DL, get(AArch64::Bcc)).addImm(CC).addMBB(TBB);
MI.eraseFromParent();
return true;
}
}
}
std::pair<unsigned, unsigned>
AArch64InstrInfo::decomposeMachineOperandsTargetFlags(unsigned TF) const {
const unsigned Mask = AArch64II::MO_FRAGMENT;
return std::make_pair(TF & Mask, TF & ~Mask);
}
ArrayRef<std::pair<unsigned, const char *>>
AArch64InstrInfo::getSerializableDirectMachineOperandTargetFlags() const {
using namespace AArch64II;
static const std::pair<unsigned, const char *> TargetFlags[] = {
{MO_PAGE, "aarch64-page"}, {MO_PAGEOFF, "aarch64-pageoff"},
{MO_G3, "aarch64-g3"}, {MO_G2, "aarch64-g2"},
{MO_G1, "aarch64-g1"}, {MO_G0, "aarch64-g0"},
{MO_HI12, "aarch64-hi12"}};
return makeArrayRef(TargetFlags);
}
ArrayRef<std::pair<unsigned, const char *>>
AArch64InstrInfo::getSerializableBitmaskMachineOperandTargetFlags() const {
using namespace AArch64II;
static const std::pair<unsigned, const char *> TargetFlags[] = {
{MO_GOT, "aarch64-got"}, {MO_NC, "aarch64-nc"}, {MO_TLS, "aarch64-tls"}};
return makeArrayRef(TargetFlags);
}
ArrayRef<std::pair<MachineMemOperand::Flags, const char *>>
AArch64InstrInfo::getSerializableMachineMemOperandTargetFlags() const {
static const std::pair<MachineMemOperand::Flags, const char *> TargetFlags[] =
{{MOSuppressPair, "aarch64-suppress-pair"},
{MOStridedAccess, "aarch64-strided-access"}};
return makeArrayRef(TargetFlags);
}
/// Constants defining how certain sequences should be outlined.
/// This encompasses how an outlined function should be called, and what kind of
/// frame should be emitted for that outlined function.
///
/// \p MachineOutlinerDefault implies that the function should be called with
/// a save and restore of LR to the stack.
///
/// That is,
///
/// I1 Save LR OUTLINED_FUNCTION:
/// I2 --> BL OUTLINED_FUNCTION I1
/// I3 Restore LR I2
/// I3
/// RET
///
/// * Call construction overhead: 3 (save + BL + restore)
/// * Frame construction overhead: 1 (ret)
/// * Requires stack fixups? Yes
///
/// \p MachineOutlinerTailCall implies that the function is being created from
/// a sequence of instructions ending in a return.
///
/// That is,
///
/// I1 OUTLINED_FUNCTION:
/// I2 --> B OUTLINED_FUNCTION I1
/// RET I2
/// RET
///
/// * Call construction overhead: 1 (B)
/// * Frame construction overhead: 0 (Return included in sequence)
/// * Requires stack fixups? No
///
/// \p MachineOutlinerNoLRSave implies that the function should be called using
/// a BL instruction, but doesn't require LR to be saved and restored. This
/// happens when LR is known to be dead.
///
/// That is,
///
/// I1 OUTLINED_FUNCTION:
/// I2 --> BL OUTLINED_FUNCTION I1
/// I3 I2
/// I3
/// RET
///
/// * Call construction overhead: 1 (BL)
/// * Frame construction overhead: 1 (RET)
/// * Requires stack fixups? No
///
/// \p MachineOutlinerThunk implies that the function is being created from
/// a sequence of instructions ending in a call. The outlined function is
/// called with a BL instruction, and the outlined function tail-calls the
/// original call destination.
///
/// That is,
///
/// I1 OUTLINED_FUNCTION:
/// I2 --> BL OUTLINED_FUNCTION I1
/// BL f I2
/// B f
/// * Call construction overhead: 1 (BL)
/// * Frame construction overhead: 0
/// * Requires stack fixups? No
///
enum MachineOutlinerClass {
MachineOutlinerDefault, /// Emit a save, restore, call, and return.
MachineOutlinerTailCall, /// Only emit a branch.
MachineOutlinerNoLRSave, /// Emit a call and return.
MachineOutlinerThunk, /// Emit a call and tail-call.
};
enum MachineOutlinerMBBFlags {
LRUnavailableSomewhere = 0x2,
HasCalls = 0x4
};
outliner::TargetCostInfo
AArch64InstrInfo::getOutliningCandidateInfo(
std::vector<outliner::Candidate> &RepeatedSequenceLocs) const {
unsigned SequenceSize = std::accumulate(
RepeatedSequenceLocs[0].front(),
std::next(RepeatedSequenceLocs[0].back()),
0, [this](unsigned Sum, const MachineInstr &MI) {
return Sum + getInstSizeInBytes(MI);
});
unsigned CallID = MachineOutlinerDefault;
unsigned FrameID = MachineOutlinerDefault;
unsigned NumBytesForCall = 12;
unsigned NumBytesToCreateFrame = 4;
// Compute liveness information for each candidate.
const TargetRegisterInfo &TRI = getRegisterInfo();
std::for_each(RepeatedSequenceLocs.begin(), RepeatedSequenceLocs.end(),
[&TRI](outliner::Candidate &C) { C.initLRU(TRI); });
// According to the AArch64 Procedure Call Standard, the following are
// undefined on entry/exit from a function call:
//
// * Registers x16, x17, (and thus w16, w17)
// * Condition codes (and thus the NZCV register)
//
// Because if this, we can't outline any sequence of instructions where
// one
// of these registers is live into/across it. Thus, we need to delete
// those
// candidates.
auto CantGuaranteeValueAcrossCall = [](outliner::Candidate &C) {
LiveRegUnits LRU = C.LRU;
return (!LRU.available(AArch64::W16) || !LRU.available(AArch64::W17) ||
!LRU.available(AArch64::NZCV));
};
// Erase every candidate that violates the restrictions above. (It could be
// true that we have viable candidates, so it's not worth bailing out in
// the case that, say, 1 out of 20 candidates violate the restructions.)
RepeatedSequenceLocs.erase(std::remove_if(RepeatedSequenceLocs.begin(),
RepeatedSequenceLocs.end(),
CantGuaranteeValueAcrossCall),
RepeatedSequenceLocs.end());
// At this point, we have only "safe" candidates to outline. Figure out
// frame + call instruction information.
unsigned LastInstrOpcode = RepeatedSequenceLocs[0].back()->getOpcode();
// If the last instruction in any candidate is a terminator, then we should
// tail call all of the candidates.
if (RepeatedSequenceLocs[0].back()->isTerminator()) {
CallID = MachineOutlinerTailCall;
FrameID = MachineOutlinerTailCall;
NumBytesForCall = 4;
NumBytesToCreateFrame = 0;
}
else if (LastInstrOpcode == AArch64::BL || LastInstrOpcode == AArch64::BLR) {
// FIXME: Do we need to check if the code after this uses the value of LR?
CallID = MachineOutlinerThunk;
FrameID = MachineOutlinerThunk;
NumBytesForCall = 4;
NumBytesToCreateFrame = 0;
}
// Make sure that LR isn't live on entry to this candidate. The only
// instructions that use LR that could possibly appear in a repeated sequence
// are calls. Therefore, we only have to check and see if LR is dead on entry
// to (or exit from) some candidate.
else if (std::all_of(RepeatedSequenceLocs.begin(),
RepeatedSequenceLocs.end(),
[](outliner::Candidate &C) {
return C.LRU.available(AArch64::LR);
})) {
CallID = MachineOutlinerNoLRSave;
FrameID = MachineOutlinerNoLRSave;
NumBytesForCall = 4;
NumBytesToCreateFrame = 4;
}
// Check if the range contains a call. These require a save + restore of the
// link register.
if (std::any_of(RepeatedSequenceLocs[0].front(),
RepeatedSequenceLocs[0].back(),
[](const MachineInstr &MI) { return MI.isCall(); }))
NumBytesToCreateFrame += 8; // Save + restore the link register.
// Handle the last instruction separately. If this is a tail call, then the
// last instruction is a call. We don't want to save + restore in this case.
// However, it could be possible that the last instruction is a call without
// it being valid to tail call this sequence. We should consider this as well.
else if (FrameID != MachineOutlinerThunk &&
FrameID != MachineOutlinerTailCall &&
RepeatedSequenceLocs[0].back()->isCall())
NumBytesToCreateFrame += 8;
return outliner::TargetCostInfo(SequenceSize, NumBytesForCall,
NumBytesToCreateFrame, CallID, FrameID);
}
bool AArch64InstrInfo::isFunctionSafeToOutlineFrom(
MachineFunction &MF, bool OutlineFromLinkOnceODRs) const {
const Function &F = MF.getFunction();
// Can F be deduplicated by the linker? If it can, don't outline from it.
if (!OutlineFromLinkOnceODRs && F.hasLinkOnceODRLinkage())
return false;
// Don't outline from functions with section markings; the program could
// expect that all the code is in the named section.
// FIXME: Allow outlining from multiple functions with the same section
// marking.
if (F.hasSection())
return false;
// Outlining from functions with redzones is unsafe since the outliner may
// modify the stack. Check if hasRedZone is true or unknown; if yes, don't
// outline from it.
AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
if (!AFI || AFI->hasRedZone().getValueOr(true))
return false;
// It's safe to outline from MF.
return true;
}
unsigned
AArch64InstrInfo::getMachineOutlinerMBBFlags(MachineBasicBlock &MBB) const {
unsigned Flags = 0x0;
// Check if there's a call inside this MachineBasicBlock. If there is, then
// set a flag.
if (std::any_of(MBB.begin(), MBB.end(),
[](MachineInstr &MI) { return MI.isCall(); }))
Flags |= MachineOutlinerMBBFlags::HasCalls;
// Check if LR is available through all of the MBB. If it's not, then set
// a flag.
assert(MBB.getParent()->getRegInfo().tracksLiveness() &&
"Suitable Machine Function for outlining must track liveness");
LiveRegUnits LRU(getRegisterInfo());
LRU.addLiveOuts(MBB);
std::for_each(MBB.rbegin(),
MBB.rend(),
[&LRU](MachineInstr &MI) { LRU.accumulate(MI); });
if (!LRU.available(AArch64::LR))
Flags |= MachineOutlinerMBBFlags::LRUnavailableSomewhere;
return Flags;
}
outliner::InstrType
AArch64InstrInfo::getOutliningType(MachineBasicBlock::iterator &MIT,
unsigned Flags) const {
MachineInstr &MI = *MIT;
MachineBasicBlock *MBB = MI.getParent();
MachineFunction *MF = MBB->getParent();
AArch64FunctionInfo *FuncInfo = MF->getInfo<AArch64FunctionInfo>();
// Don't outline LOHs.
if (FuncInfo->getLOHRelated().count(&MI))
return outliner::InstrType::Illegal;
// Don't allow debug values to impact outlining type.
if (MI.isDebugInstr() || MI.isIndirectDebugValue())
return outliner::InstrType::Invisible;
// At this point, KILL instructions don't really tell us much so we can go
// ahead and skip over them.
if (MI.isKill())
return outliner::InstrType::Invisible;
// Is this a terminator for a basic block?
if (MI.isTerminator()) {
// Is this the end of a function?
if (MI.getParent()->succ_empty())
return outliner::InstrType::Legal;
// It's not, so don't outline it.
return outliner::InstrType::Illegal;
}
// Make sure none of the operands are un-outlinable.
for (const MachineOperand &MOP : MI.operands()) {
if (MOP.isCPI() || MOP.isJTI() || MOP.isCFIIndex() || MOP.isFI() ||
MOP.isTargetIndex())
return outliner::InstrType::Illegal;
// If it uses LR or W30 explicitly, then don't touch it.
if (MOP.isReg() && !MOP.isImplicit() &&
(MOP.getReg() == AArch64::LR || MOP.getReg() == AArch64::W30))
return outliner::InstrType::Illegal;
}
// Special cases for instructions that can always be outlined, but will fail
// the later tests. e.g, ADRPs, which are PC-relative use LR, but can always
// be outlined because they don't require a *specific* value to be in LR.
if (MI.getOpcode() == AArch64::ADRP)
return outliner::InstrType::Legal;
// If MI is a call we might be able to outline it. We don't want to outline
// any calls that rely on the position of items on the stack. When we outline
// something containing a call, we have to emit a save and restore of LR in
// the outlined function. Currently, this always happens by saving LR to the
// stack. Thus, if we outline, say, half the parameters for a function call
// plus the call, then we'll break the callee's expectations for the layout
// of the stack.
//
// FIXME: Allow calls to functions which construct a stack frame, as long
// as they don't access arguments on the stack.
// FIXME: Figure out some way to analyze functions defined in other modules.
// We should be able to compute the memory usage based on the IR calling
// convention, even if we can't see the definition.
if (MI.isCall()) {
// Get the function associated with the call. Look at each operand and find
// the one that represents the callee and get its name.
const Function *Callee = nullptr;
for (const MachineOperand &MOP : MI.operands()) {
if (MOP.isGlobal()) {
Callee = dyn_cast<Function>(MOP.getGlobal());
break;
}
}
// Never outline calls to mcount. There isn't any rule that would require
// this, but the Linux kernel's "ftrace" feature depends on it.
if (Callee && Callee->getName() == "\01_mcount")
return outliner::InstrType::Illegal;
// If we don't know anything about the callee, assume it depends on the
// stack layout of the caller. In that case, it's only legal to outline
// as a tail-call. Whitelist the call instructions we know about so we
// don't get unexpected results with call pseudo-instructions.
auto UnknownCallOutlineType = outliner::InstrType::Illegal;
if (MI.getOpcode() == AArch64::BLR || MI.getOpcode() == AArch64::BL)
UnknownCallOutlineType = outliner::InstrType::LegalTerminator;
if (!Callee)
return UnknownCallOutlineType;
// We have a function we have information about. Check it if it's something
// can safely outline.
MachineFunction *CalleeMF = MF->getMMI().getMachineFunction(*Callee);
// We don't know what's going on with the callee at all. Don't touch it.
if (!CalleeMF)
return UnknownCallOutlineType;
// Check if we know anything about the callee saves on the function. If we
// don't, then don't touch it, since that implies that we haven't
// computed anything about its stack frame yet.
MachineFrameInfo &MFI = CalleeMF->getFrameInfo();
if (!MFI.isCalleeSavedInfoValid() || MFI.getStackSize() > 0 ||
MFI.getNumObjects() > 0)
return UnknownCallOutlineType;
// At this point, we can say that CalleeMF ought to not pass anything on the
// stack. Therefore, we can outline it.
return outliner::InstrType::Legal;
}
// Don't outline positions.
if (MI.isPosition())
return outliner::InstrType::Illegal;
// Don't touch the link register or W30.
if (MI.readsRegister(AArch64::W30, &getRegisterInfo()) ||
MI.modifiesRegister(AArch64::W30, &getRegisterInfo()))
return outliner::InstrType::Illegal;
// Does this use the stack?
if (MI.modifiesRegister(AArch64::SP, &RI) ||
MI.readsRegister(AArch64::SP, &RI)) {
// True if there is no chance that any outlined candidate from this range
// could require stack fixups. That is, both
// * LR is available in the range (No save/restore around call)
// * The range doesn't include calls (No save/restore in outlined frame)
// are true.
// FIXME: This is very restrictive; the flags check the whole block,
// not just the bit we will try to outline.
bool MightNeedStackFixUp =
(Flags & (MachineOutlinerMBBFlags::LRUnavailableSomewhere |
MachineOutlinerMBBFlags::HasCalls));
// If this instruction is in a range where it *never* needs to be fixed
// up, then we can *always* outline it. This is true even if it's not
// possible to fix that instruction up.
//
// Why? Consider two equivalent instructions I1, I2 where both I1 and I2
// use SP. Suppose that I1 sits within a range that definitely doesn't
// need stack fixups, while I2 sits in a range that does.
//
// First, I1 can be outlined as long as we *never* fix up the stack in
// any sequence containing it. I1 is already a safe instruction in the
// original program, so as long as we don't modify it we're good to go.
// So this leaves us with showing that outlining I2 won't break our
// program.
//
// Suppose I1 and I2 belong to equivalent candidate sequences. When we
// look at I2, we need to see if it can be fixed up. Suppose I2, (and
// thus I1) cannot be fixed up. Then I2 will be assigned an unique
// integer label; thus, I2 cannot belong to any candidate sequence (a
// contradiction). Suppose I2 can be fixed up. Then I1 can be fixed up
// as well, so we're good. Thus, I1 is always safe to outline.
//
// This gives us two things: first off, it buys us some more instructions
// for our search space by deeming stack instructions illegal only when
// they can't be fixed up AND we might have to fix them up. Second off,
// This allows us to catch tricky instructions like, say,
// %xi = ADDXri %sp, n, 0. We can't safely outline these since they might
// be paired with later SUBXris, which might *not* end up being outlined.
// If we mess with the stack to save something, then an ADDXri messes with
// it *after*, then we aren't going to restore the right something from
// the stack if we don't outline the corresponding SUBXri first. ADDXris and
// SUBXris are extremely common in prologue/epilogue code, so supporting
// them in the outliner can be a pretty big win!
if (!MightNeedStackFixUp)
return outliner::InstrType::Legal;
// Any modification of SP will break our code to save/restore LR.
// FIXME: We could handle some instructions which add a constant offset to
// SP, with a bit more work.
if (MI.modifiesRegister(AArch64::SP, &RI))
return outliner::InstrType::Illegal;
// At this point, we have a stack instruction that we might need to fix
// up. We'll handle it if it's a load or store.
if (MI.mayLoadOrStore()) {
unsigned Base; // Filled with the base regiser of MI.
int64_t Offset; // Filled with the offset of MI.
unsigned DummyWidth;
// Does it allow us to offset the base register and is the base SP?
if (!getMemOpBaseRegImmOfsWidth(MI, Base, Offset, DummyWidth, &RI) ||
Base != AArch64::SP)
return outliner::InstrType::Illegal;
// Find the minimum/maximum offset for this instruction and check if
// fixing it up would be in range.
int64_t MinOffset, MaxOffset; // Unscaled offsets for the instruction.
unsigned Scale; // The scale to multiply the offsets by.
getMemOpInfo(MI.getOpcode(), Scale, DummyWidth, MinOffset, MaxOffset);
// TODO: We should really test what happens if an instruction overflows.
// This is tricky to test with IR tests, but when the outliner is moved
// to a MIR test, it really ought to be checked.
Offset += 16; // Update the offset to what it would be if we outlined.
if (Offset < MinOffset * Scale || Offset > MaxOffset * Scale)
return outliner::InstrType::Illegal;
// It's in range, so we can outline it.
return outliner::InstrType::Legal;
}
// FIXME: Add handling for instructions like "add x0, sp, #8".
// We can't fix it up, so don't outline it.
return outliner::InstrType::Illegal;
}
return outliner::InstrType::Legal;
}
void AArch64InstrInfo::fixupPostOutline(MachineBasicBlock &MBB) const {
for (MachineInstr &MI : MBB) {
unsigned Base, Width;
int64_t Offset;
// Is this a load or store with an immediate offset with SP as the base?
if (!MI.mayLoadOrStore() ||
!getMemOpBaseRegImmOfsWidth(MI, Base, Offset, Width, &RI) ||
Base != AArch64::SP)
continue;
// It is, so we have to fix it up.
unsigned Scale;
int64_t Dummy1, Dummy2;
MachineOperand &StackOffsetOperand = getMemOpBaseRegImmOfsOffsetOperand(MI);
assert(StackOffsetOperand.isImm() && "Stack offset wasn't immediate!");
getMemOpInfo(MI.getOpcode(), Scale, Width, Dummy1, Dummy2);
assert(Scale != 0 && "Unexpected opcode!");
// We've pushed the return address to the stack, so add 16 to the offset.
// This is safe, since we already checked if it would overflow when we
// checked if this instruction was legal to outline.
int64_t NewImm = (Offset + 16) / Scale;
StackOffsetOperand.setImm(NewImm);
}
}
void AArch64InstrInfo::buildOutlinedFrame(
MachineBasicBlock &MBB, MachineFunction &MF,
const outliner::TargetCostInfo &TCI) const {
// For thunk outlining, rewrite the last instruction from a call to a
// tail-call.
if (TCI.FrameConstructionID == MachineOutlinerThunk) {
MachineInstr *Call = &*--MBB.instr_end();
unsigned TailOpcode;
if (Call->getOpcode() == AArch64::BL) {
TailOpcode = AArch64::TCRETURNdi;
} else {
assert(Call->getOpcode() == AArch64::BLR);
TailOpcode = AArch64::TCRETURNri;
}
MachineInstr *TC = BuildMI(MF, DebugLoc(), get(TailOpcode))
.add(Call->getOperand(0))
.addImm(0);
MBB.insert(MBB.end(), TC);
Call->eraseFromParent();
}
// Is there a call in the outlined range?
auto IsNonTailCall = [](MachineInstr &MI) {
return MI.isCall() && !MI.isReturn();
};
if (std::any_of(MBB.instr_begin(), MBB.instr_end(), IsNonTailCall)) {
// Fix up the instructions in the range, since we're going to modify the
// stack.
assert(TCI.FrameConstructionID != MachineOutlinerDefault &&
"Can only fix up stack references once");
fixupPostOutline(MBB);
// LR has to be a live in so that we can save it.
MBB.addLiveIn(AArch64::LR);
MachineBasicBlock::iterator It = MBB.begin();
MachineBasicBlock::iterator Et = MBB.end();
if (TCI.FrameConstructionID == MachineOutlinerTailCall ||
TCI.FrameConstructionID == MachineOutlinerThunk)
Et = std::prev(MBB.end());
// Insert a save before the outlined region
MachineInstr *STRXpre = BuildMI(MF, DebugLoc(), get(AArch64::STRXpre))
.addReg(AArch64::SP, RegState::Define)
.addReg(AArch64::LR)
.addReg(AArch64::SP)
.addImm(-16);
It = MBB.insert(It, STRXpre);
const TargetSubtargetInfo &STI = MF.getSubtarget();
const MCRegisterInfo *MRI = STI.getRegisterInfo();
unsigned DwarfReg = MRI->getDwarfRegNum(AArch64::LR, true);
// Add a CFI saying the stack was moved 16 B down.
int64_t StackPosEntry =
MF.addFrameInst(MCCFIInstruction::createDefCfaOffset(nullptr, 16));
BuildMI(MBB, It, DebugLoc(), get(AArch64::CFI_INSTRUCTION))
.addCFIIndex(StackPosEntry)
.setMIFlags(MachineInstr::FrameSetup);
// Add a CFI saying that the LR that we want to find is now 16 B higher than
// before.
int64_t LRPosEntry =
MF.addFrameInst(MCCFIInstruction::createOffset(nullptr, DwarfReg, 16));
BuildMI(MBB, It, DebugLoc(), get(AArch64::CFI_INSTRUCTION))
.addCFIIndex(LRPosEntry)
.setMIFlags(MachineInstr::FrameSetup);
// Insert a restore before the terminator for the function.
MachineInstr *LDRXpost = BuildMI(MF, DebugLoc(), get(AArch64::LDRXpost))
.addReg(AArch64::SP, RegState::Define)
.addReg(AArch64::LR, RegState::Define)
.addReg(AArch64::SP)
.addImm(16);
Et = MBB.insert(Et, LDRXpost);
}
// If this is a tail call outlined function, then there's already a return.
if (TCI.FrameConstructionID == MachineOutlinerTailCall ||
TCI.FrameConstructionID == MachineOutlinerThunk)
return;
// It's not a tail call, so we have to insert the return ourselves.
MachineInstr *ret = BuildMI(MF, DebugLoc(), get(AArch64::RET))
.addReg(AArch64::LR, RegState::Undef);
MBB.insert(MBB.end(), ret);
// Did we have to modify the stack by saving the link register?
if (TCI.FrameConstructionID == MachineOutlinerNoLRSave)
return;
// We modified the stack.
// Walk over the basic block and fix up all the stack accesses.
fixupPostOutline(MBB);
}
MachineBasicBlock::iterator AArch64InstrInfo::insertOutlinedCall(
Module &M, MachineBasicBlock &MBB, MachineBasicBlock::iterator &It,
MachineFunction &MF, const outliner::TargetCostInfo &TCI) const {
// Are we tail calling?
if (TCI.CallConstructionID == MachineOutlinerTailCall) {
// If yes, then we can just branch to the label.
It = MBB.insert(It, BuildMI(MF, DebugLoc(), get(AArch64::TCRETURNdi))
.addGlobalAddress(M.getNamedValue(MF.getName()))
.addImm(0));
return It;
}
// Are we saving the link register?
if (TCI.CallConstructionID == MachineOutlinerNoLRSave ||
TCI.CallConstructionID == MachineOutlinerThunk) {
// No, so just insert the call.
It = MBB.insert(It, BuildMI(MF, DebugLoc(), get(AArch64::BL))
.addGlobalAddress(M.getNamedValue(MF.getName())));
return It;
}
// We want to return the spot where we inserted the call.
MachineBasicBlock::iterator CallPt;
// We have a default call. Save the link register.
MachineInstr *STRXpre = BuildMI(MF, DebugLoc(), get(AArch64::STRXpre))
.addReg(AArch64::SP, RegState::Define)
.addReg(AArch64::LR)
.addReg(AArch64::SP)
.addImm(-16);
It = MBB.insert(It, STRXpre);
It++;
// Insert the call.
It = MBB.insert(It, BuildMI(MF, DebugLoc(), get(AArch64::BL))
.addGlobalAddress(M.getNamedValue(MF.getName())));
CallPt = It;
It++;
// Restore the link register.
MachineInstr *LDRXpost = BuildMI(MF, DebugLoc(), get(AArch64::LDRXpost))
.addReg(AArch64::SP, RegState::Define)
.addReg(AArch64::LR, RegState::Define)
.addReg(AArch64::SP)
.addImm(16);
It = MBB.insert(It, LDRXpost);
return CallPt;
}
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