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//=- llvm/CodeGen/CriticalAntiDepBreaker.h - Anti-Dep Support -*- C++ -*-=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the CriticalAntiDepBreaker class, which
// implements register anti-dependence breaking along a blocks
// critical path during post-RA scheduler.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_CRITICALANTIDEPBREAKER_H
#define LLVM_CODEGEN_CRITICALANTIDEPBREAKER_H
#include "AntiDepBreaker.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterClassInfo.h"
#include "llvm/CodeGen/ScheduleDAG.h"
#include <map>
namespace llvm {
class RegisterClassInfo;
class TargetInstrInfo;
class TargetRegisterInfo;
class CriticalAntiDepBreaker : public AntiDepBreaker {
MachineFunction& MF;
MachineRegisterInfo &MRI;
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
const RegisterClassInfo &RegClassInfo;
/// AllocatableSet - The set of allocatable registers.
/// We'll be ignoring anti-dependencies on non-allocatable registers,
/// because they may not be safe to break.
const BitVector AllocatableSet;
/// Classes - For live regs that are only used in one register class in a
/// live range, the register class. If the register is not live, the
/// corresponding value is null. If the register is live but used in
/// multiple register classes, the corresponding value is -1 casted to a
/// pointer.
std::vector<const TargetRegisterClass*> Classes;
/// RegRefs - Map registers to all their references within a live range.
std::multimap<unsigned, MachineOperand *> RegRefs;
typedef std::multimap<unsigned, MachineOperand *>::const_iterator
RegRefIter;
/// KillIndices - The index of the most recent kill (proceeding bottom-up),
/// or ~0u if the register is not live.
std::vector<unsigned> KillIndices;
/// DefIndices - The index of the most recent complete def (proceeding
/// bottom up), or ~0u if the register is live.
std::vector<unsigned> DefIndices;
/// KeepRegs - A set of registers which are live and cannot be changed to
/// break anti-dependencies.
BitVector KeepRegs;
public:
CriticalAntiDepBreaker(MachineFunction& MFi, const RegisterClassInfo&);
~CriticalAntiDepBreaker();
/// Start - Initialize anti-dep breaking for a new basic block.
void StartBlock(MachineBasicBlock *BB) override;
/// BreakAntiDependencies - Identifiy anti-dependencies along the critical
/// path
/// of the ScheduleDAG and break them by renaming registers.
///
unsigned BreakAntiDependencies(const std::vector<SUnit>& SUnits,
MachineBasicBlock::iterator Begin,
MachineBasicBlock::iterator End,
unsigned InsertPosIndex,
DbgValueVector &DbgValues) override;
/// Observe - Update liveness information to account for the current
/// instruction, which will not be scheduled.
///
void Observe(MachineInstr *MI, unsigned Count,
unsigned InsertPosIndex) override;
/// Finish - Finish anti-dep breaking for a basic block.
void FinishBlock() override;
private:
void PrescanInstruction(MachineInstr *MI);
void ScanInstruction(MachineInstr *MI, unsigned Count);
bool isNewRegClobberedByRefs(RegRefIter RegRefBegin,
RegRefIter RegRefEnd,
unsigned NewReg);
unsigned findSuitableFreeRegister(RegRefIter RegRefBegin,
RegRefIter RegRefEnd,
unsigned AntiDepReg,
unsigned LastNewReg,
const TargetRegisterClass *RC,
SmallVectorImpl<unsigned> &Forbid);
};
}
#endif
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