include/llvm/Target/TargetInstrItineraries.h

//===-- llvm/Target/TargetInstrItineraries.h - Scheduling -------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the James M. Laskey and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file describes the structures used for instruction itineraries and
// states.  This is used by schedulers to determine instruction states and
// latencies.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_TARGET_TARGETINSTRITINERARIES_H
#define LLVM_TARGET_TARGETINSTRITINERARIES_H

namespace llvm {

//===----------------------------------------------------------------------===//
// Instruction stage - These values represent a step in the execution of an
// instruction.  The latency represents the number of discrete time slots used
// need to complete the stage.  Units represent the choice of functional units
// that can be used to complete the stage.  Eg. IntUnit1, IntUnit2.
//
struct InstrStage {
  unsigned Cycles;  // Length of stage in machine cycles
  unsigned Units;   // Choice of functional units
};


//===----------------------------------------------------------------------===//
// Instruction itinerary - An itinerary represents a sequential series of steps
// required to complete an instruction.  Itineraries are represented as
// sequences of instruction stages.
//
struct InstrItinerary {
  unsigned First;    // Index of first stage in itinerary
  unsigned Last;     // Index of last + 1 stage in itinerary
};


} // End llvm namespace

#endif