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llvm-mirror/include/llvm/CodeGen/TargetSchedule.h
2012-09-18 04:03:34 +00:00

80 lines
3.0 KiB
C++

//===-- llvm/CodeGen/TargetSchedule.h - Sched Machine Model -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a wrapper around MCSchedModel that allows the interface to
// benefit from information currently only available in TargetInstrInfo.
// Ideally, the scheduling interface would be fully defined in the MC layer.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_TARGETSCHEDMODEL_H
#define LLVM_TARGET_TARGETSCHEDMODEL_H
#include "llvm/MC/MCSchedule.h"
#include "llvm/MC/MCInstrItineraries.h"
namespace llvm {
class TargetRegisterInfo;
class TargetSubtargetInfo;
class TargetInstrInfo;
class MachineInstr;
/// Provide an instruction scheduling machine model to CodeGen passes.
class TargetSchedModel {
// For efficiency, hold a copy of the statically defined MCSchedModel for this
// processor.
MCSchedModel SchedModel;
InstrItineraryData InstrItins;
const TargetSubtargetInfo *STI;
const TargetInstrInfo *TII;
public:
TargetSchedModel(): STI(0), TII(0) {}
void init(const MCSchedModel &sm, const TargetSubtargetInfo *sti,
const TargetInstrInfo *tii);
const TargetInstrInfo *getInstrInfo() const { return TII; }
/// Return true if this machine model includes an instruction-level scheduling
/// model. This is more detailed than the course grain IssueWidth and default
/// latency properties, but separate from the per-cycle itinerary data.
bool hasInstrSchedModel() const { return SchedModel.hasInstrSchedModel(); }
/// Return true if this machine model includes cycle-to-cycle itinerary
/// data. This models scheduling at each stage in the processor pipeline.
bool hasInstrItineraries() const { return !InstrItins.isEmpty(); }
/// computeOperandLatency - Compute and return the latency of the given data
/// dependent def and use when the operand indices are already known. UseMI
/// may be NULL for an unknown user.
///
/// FindMin may be set to get the minimum vs. expected latency. Minimum
/// latency is used for scheduling groups, while expected latency is for
/// instruction cost and critical path.
unsigned computeOperandLatency(const MachineInstr *DefMI, unsigned DefOperIdx,
const MachineInstr *UseMI, unsigned UseOperIdx,
bool FindMin) const;
unsigned getProcessorID() const { return SchedModel.getProcessorID(); }
private:
/// getDefLatency is a helper for computeOperandLatency. Return the
/// instruction's latency if operand lookup is not required.
/// Otherwise return -1.
int getDefLatency(const MachineInstr *DefMI, bool FindMin) const;
/// Return the MCSchedClassDesc for this instruction.
const MCSchedClassDesc *resolveSchedClass(const MachineInstr *MI) const;
};
} // namespace llvm
#endif