//===-- ScheduleDAG.cpp - Implement a trivial DAG scheduler ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by James M. Laskey and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements a simple two pass scheduler. The first pass attempts to push
// backward any lengthy instructions and critical paths. The second pass packs
// instructions into semi-optimal time slots.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "sched"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetInstrItineraries.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include <iostream>
using namespace llvm;
namespace {
// Style of scheduling to use.
enum ScheduleChoices {
noScheduling,
simpleScheduling,
simpleNoItinScheduling
};
} // namespace
cl::opt<ScheduleChoices> ScheduleStyle("sched",
cl::desc("Choose scheduling style"),
cl::init(noScheduling),
cl::values(
clEnumValN(noScheduling, "none",
"Trivial emission with no analysis"),
clEnumValN(simpleScheduling, "simple",
"Minimize critical path and maximize processor utilization"),
clEnumValN(simpleNoItinScheduling, "simple-noitin",
"Same as simple except using generic latency"),
clEnumValEnd));
#ifndef NDEBUG
static cl::opt<bool>
ViewDAGs("view-sched-dags", cl::Hidden,
cl::desc("Pop up a window to show sched dags as they are processed"));
#else
static const bool ViewDAGs = 0;
#endif
namespace {
//===----------------------------------------------------------------------===//
///
/// BitsIterator - Provides iteration through individual bits in a bit vector.
///
template<class T>
class BitsIterator {
private:
T Bits; // Bits left to iterate through
public:
/// Ctor.
BitsIterator(T 