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//=- llvm/CodeGen/AntiDepBreaker.h - Anti-Dependence Breaking -*- 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 AntiDepBreaker class, which implements
// anti-dependence breaking heuristics for post-register-allocation scheduling.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_ANTIDEPBREAKER_H
#define LLVM_LIB_CODEGEN_ANTIDEPBREAKER_H
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/ScheduleDAG.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include <vector>
namespace llvm {
/// This class works in conjunction with the post-RA scheduler to rename
/// registers to break register anti-dependencies (WAR hazards).
class AntiDepBreaker {
public:
typedef std::vector<std::pair<MachineInstr *, MachineInstr *> >
DbgValueVector;
virtual ~AntiDepBreaker();
/// Initialize anti-dep breaking for a new basic block.
virtual void StartBlock(MachineBasicBlock *BB) =0;
/// Identifiy anti-dependencies within a basic-block region and break them by
/// renaming registers. Return the number of anti-dependencies broken.
virtual unsigned BreakAntiDependencies(const std::vector<SUnit>& SUnits,
MachineBasicBlock::iterator Begin,
MachineBasicBlock::iterator End,
unsigned InsertPosIndex,
DbgValueVector &DbgValues) = 0;
/// Update liveness information to account for the current
/// instruction, which will not be scheduled.
virtual void Observe(MachineInstr *MI, unsigned Count,
unsigned InsertPosIndex) =0;
/// Finish anti-dep breaking for a basic block.
virtual void FinishBlock() =0;
/// Update DBG_VALUE if dependency breaker is updating
/// other machine instruction to use NewReg.
void UpdateDbgValue(MachineInstr *MI, unsigned OldReg, unsigned NewReg) {
assert (MI->isDebugValue() && "MI is not DBG_VALUE!");
if (MI && MI->getOperand(0).isReg() && MI->getOperand(0).getReg() == OldReg)
MI->getOperand(0).setReg(NewReg);
}
};
}
#endif
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