llvm/llvm/lib/Target/ARM/MLxExpansionPass.cpp

//===-- MLxExpansionPass.cpp - Expand MLx instrs to avoid hazards ---------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Expand VFP / NEON floating point MLA / MLS instructions (each to a pair of
// multiple and add / sub instructions) when special VMLx hazards are detected.
//
//===----------------------------------------------------------------------===//

#include "ARM.h"
#include "ARMBaseInstrInfo.h"
#include "ARMSubtarget.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
usingnamespacellvm;

#define DEBUG_TYPE …

static cl::opt<bool>
ForceExapnd("expand-all-fp-mlx", cl::init(false), cl::Hidden);
static cl::opt<unsigned>
ExpandLimit("expand-limit", cl::init(~0U), cl::Hidden);

STATISTIC(NumExpand, "Number of fp MLA / MLS instructions expanded");

namespace {
  struct MLxExpansion : public MachineFunctionPass { … };
  char MLxExpansion::ID = …;
}

void MLxExpansion::clearStack() { … }

void MLxExpansion::pushStack(MachineInstr *MI) { … }

MachineInstr *MLxExpansion::getAccDefMI(MachineInstr *MI) const { … }

unsigned MLxExpansion::getDefReg(MachineInstr *MI) const { … }

/// hasLoopHazard - Check whether an MLx instruction is chained to itself across
/// a single-MBB loop.
bool MLxExpansion::hasLoopHazard(MachineInstr *MI) const { … }

bool MLxExpansion::hasRAWHazard(unsigned Reg, MachineInstr *MI) const { … }

static bool isFpMulInstruction(unsigned Opcode) { … }

bool MLxExpansion::FindMLxHazard(MachineInstr *MI) { … }

/// ExpandFPMLxInstructions - Expand a MLA / MLS instruction into a pair
/// of MUL + ADD / SUB instructions.
void
MLxExpansion::ExpandFPMLxInstruction(MachineBasicBlock &MBB, MachineInstr *MI,
                                     unsigned MulOpc, unsigned AddSubOpc,
                                     bool NegAcc, bool HasLane) { … }

bool MLxExpansion::ExpandFPMLxInstructions(MachineBasicBlock &MBB) { … }

bool MLxExpansion::runOnMachineFunction(MachineFunction &Fn) { … }

FunctionPass *llvm::createMLxExpansionPass() { … }