llvm/llvm/lib/Target/Sparc/DelaySlotFiller.cpp

//===-- DelaySlotFiller.cpp - SPARC delay slot filler ---------------------===//
//
// 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 is a simple local pass that attempts to fill delay slots with useful
// instructions. If no instructions can be moved into the delay slot, then a
// NOP is placed.
//===----------------------------------------------------------------------===//

#include "Sparc.h"
#include "SparcSubtarget.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetMachine.h"

usingnamespacellvm;

#define DEBUG_TYPE …

STATISTIC(FilledSlots, "Number of delay slots filled");

static cl::opt<bool> DisableDelaySlotFiller(
  "disable-sparc-delay-filler",
  cl::init(false),
  cl::desc("Disable the Sparc delay slot filler."),
  cl::Hidden);

namespace {
  struct Filler : public MachineFunctionPass { … };
  char Filler::ID = …;
} // end of anonymous namespace

/// createSparcDelaySlotFillerPass - Returns a pass that fills in delay
/// slots in Sparc MachineFunctions
///
FunctionPass *llvm::createSparcDelaySlotFillerPass() { … }


/// runOnMachineBasicBlock - Fill in delay slots for the given basic block.
/// We assume there is only one delay slot per delayed instruction.
///
bool Filler::runOnMachineBasicBlock(MachineBasicBlock &MBB) { … }

MachineBasicBlock::iterator
Filler::findDelayInstr(MachineBasicBlock &MBB,
                       MachineBasicBlock::iterator slot)
{ … }

bool Filler::delayHasHazard(MachineBasicBlock::iterator candidate,
                            bool &sawLoad,
                            bool &sawStore,
                            SmallSet<unsigned, 32> &RegDefs,
                            SmallSet<unsigned, 32> &RegUses)
{ … }


void Filler::insertCallDefsUses(MachineBasicBlock::iterator MI,
                                SmallSet<unsigned, 32>& RegDefs,
                                SmallSet<unsigned, 32>& RegUses)
{ … }

// Insert Defs and Uses of MI into the sets RegDefs and RegUses.
void Filler::insertDefsUses(MachineBasicBlock::iterator MI,
                            SmallSet<unsigned, 32>& RegDefs,
                            SmallSet<unsigned, 32>& RegUses)
{ … }

// returns true if the Reg or its alias is in the RegSet.
bool Filler::IsRegInSet(SmallSet<unsigned, 32>& RegSet, unsigned Reg)
{ … }

bool Filler::needsUnimp(MachineBasicBlock::iterator I, unsigned &StructSize)
{ … }

static bool combineRestoreADD(MachineBasicBlock::iterator RestoreMI,
                              MachineBasicBlock::iterator AddMI,
                              const TargetInstrInfo *TII)
{ … }

static bool combineRestoreOR(MachineBasicBlock::iterator RestoreMI,
                             MachineBasicBlock::iterator OrMI,
                             const TargetInstrInfo *TII)
{ … }

static bool combineRestoreSETHIi(MachineBasicBlock::iterator RestoreMI,
                                 MachineBasicBlock::iterator SetHiMI,
                                 const TargetInstrInfo *TII)
{ … }

bool Filler::tryCombineRestoreWithPrevInst(MachineBasicBlock &MBB,
                                        MachineBasicBlock::iterator MBBI)
{ … }