llvm/llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp

//===- AggressiveAntiDepBreaker.cpp - Anti-dep breaker --------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the AggressiveAntiDepBreaker class, which
// implements register anti-dependence breaking during post-RA
// scheduling. It attempts to break all anti-dependencies within a
// block.
//
//===----------------------------------------------------------------------===//

#include "AggressiveAntiDepBreaker.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterClassInfo.h"
#include "llvm/CodeGen/ScheduleDAG.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGenTypes/MachineValueType.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <utility>

usingnamespacellvm;

#define DEBUG_TYPE …

// If DebugDiv > 0 then only break antidep with (ID % DebugDiv) == DebugMod
static cl::opt<int>
DebugDiv("agg-antidep-debugdiv",
         cl::desc("Debug control for aggressive anti-dep breaker"),
         cl::init(0), cl::Hidden);

static cl::opt<int>
DebugMod("agg-antidep-debugmod",
         cl::desc("Debug control for aggressive anti-dep breaker"),
         cl::init(0), cl::Hidden);

AggressiveAntiDepState::AggressiveAntiDepState(const unsigned TargetRegs,
                                               MachineBasicBlock *BB)
    : … { … }

unsigned AggressiveAntiDepState::GetGroup(unsigned Reg) { … }

void AggressiveAntiDepState::GetGroupRegs(
  unsigned Group,
  std::vector<unsigned> &Regs,
  std::multimap<unsigned, AggressiveAntiDepState::RegisterReference> *RegRefs)
{ … }

unsigned AggressiveAntiDepState::UnionGroups(unsigned Reg1, unsigned Reg2) { … }

unsigned AggressiveAntiDepState::LeaveGroup(unsigned Reg) { … }

bool AggressiveAntiDepState::IsLive(unsigned Reg) { … }

AggressiveAntiDepBreaker::AggressiveAntiDepBreaker(
    MachineFunction &MFi, const RegisterClassInfo &RCI,
    TargetSubtargetInfo::RegClassVector &CriticalPathRCs)
    : … { … }

AggressiveAntiDepBreaker::~AggressiveAntiDepBreaker() { … }

void AggressiveAntiDepBreaker::StartBlock(MachineBasicBlock *BB) { … }

void AggressiveAntiDepBreaker::FinishBlock() { … }

void AggressiveAntiDepBreaker::Observe(MachineInstr &MI, unsigned Count,
                                       unsigned InsertPosIndex) { … }

bool AggressiveAntiDepBreaker::IsImplicitDefUse(MachineInstr &MI,
                                                MachineOperand &MO) { … }

void AggressiveAntiDepBreaker::GetPassthruRegs(
    MachineInstr &MI, std::set<unsigned> &PassthruRegs) { … }

/// AntiDepEdges - Return in Edges the anti- and output- dependencies
/// in SU that we want to consider for breaking.
static void AntiDepEdges(const SUnit *SU, std::vector<const SDep *> &Edges) { … }

/// CriticalPathStep - Return the next SUnit after SU on the bottom-up
/// critical path.
static const SUnit *CriticalPathStep(const SUnit *SU) { … }

void AggressiveAntiDepBreaker::HandleLastUse(unsigned Reg, unsigned KillIdx,
                                             const char *tag,
                                             const char *header,
                                             const char *footer) { … }

void AggressiveAntiDepBreaker::PrescanInstruction(
    MachineInstr &MI, unsigned Count, std::set<unsigned> &PassthruRegs) { … }

void AggressiveAntiDepBreaker::ScanInstruction(MachineInstr &MI,
                                               unsigned Count) { … }

BitVector AggressiveAntiDepBreaker::GetRenameRegisters(unsigned Reg) { … }

bool AggressiveAntiDepBreaker::FindSuitableFreeRegisters(
    unsigned SuperReg, unsigned AntiDepGroupIndex, RenameOrderType &RenameOrder,
    std::map<unsigned, unsigned> &RenameMap) { … }

/// BreakAntiDependencies - Identifiy anti-dependencies within the
/// ScheduleDAG and break them by renaming registers.
unsigned AggressiveAntiDepBreaker::BreakAntiDependencies(
                              const std::vector<SUnit> &SUnits,
                              MachineBasicBlock::iterator Begin,
                              MachineBasicBlock::iterator End,
                              unsigned InsertPosIndex,
                              DbgValueVector &DbgValues) { … }

AntiDepBreaker *llvm::createAggressiveAntiDepBreaker(
    MachineFunction &MFi, const RegisterClassInfo &RCI,
    TargetSubtargetInfo::RegClassVector &CriticalPathRCs) { … }