path: root/lib/CodeGen/IfConversion.cpp

//===-- IfConversion.cpp - Machine code if conversion pass. ---------------===//
//
//                     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 machine instruction level if-conversion pass.
//
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "ifcvt"
#include "llvm/Function.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
using namespace llvm;

namespace {
  // Hidden options for help debugging.
  cl::opt<int> IfCvtFnStart("ifcvt-fn-start", cl::init(-1), cl::Hidden);
  cl::opt<int> IfCvtFnStop("ifcvt-fn-stop", cl::init(-1), cl::Hidden);
  cl::opt<int> IfCvtLimit("ifcvt-limit", cl::init(-1), cl::Hidden);
  cl::opt<bool> DisableSimple("disable-ifcvt-simple", 
                              cl::init(false), cl::Hidden);
  cl::opt<bool> DisableSimpleF("disable-ifcvt-simple-false", 
                               cl::init(false), cl::Hidden);
  cl::opt<bool> DisableTriangle("disable-ifcvt-triangle", 
                                cl::init(false), cl::Hidden);
  cl::opt<bool> DisableTriangleR("disable-ifcvt-triangle-rev", 
                                 cl::init(false), cl::Hidden);
  cl::opt<bool> DisableTriangleF("disable-ifcvt-triangle-false", 
                                 cl::init(false), cl::Hidden);
  cl::opt<bool> DisableTriangleFR("disable-ifcvt-triangle-false-rev", 
                                  cl::init(false), cl::Hidden);
  cl::opt<bool> DisableDiamond("disable-ifcvt-diamond", 
                               cl::init(false), cl::Hidden);
}

STATISTIC(NumSimple,       "Number of simple if-conversions performed");
STATISTIC(NumSimpleFalse,  "Number of simple (F) if-conversions performed");
STATISTIC(NumTriangle,     "Number of triangle if-conversions performed");
STATISTIC(NumTriangleRev,  "Number of triangle (R) if-conversions performed");
STATISTIC(NumTriangleFalse,"Number of triangle (F) if-conversions performed");
STATISTIC(NumTriangleFRev, "Number of triangle (F/R) if-conversions performed");
STATISTIC(NumDiamonds,     "Number of diamond if-conversions performed");
STATISTIC(NumIfConvBBs,    "Number of if-converted blocks");
STATISTIC(NumDupBBs,       "Number of duplicated blocks");

namespace {
  class IfConverter : public MachineFunctionPass {
    enum IfcvtKind {
      ICNotClassfied,  // BB data valid, but not classified.
      ICSimpleFalse,   // Same as ICSimple, but on the false path.
      ICSimple,        // BB is entry of an one split, no rejoin sub-CFG.
      ICTriangleFRev,  // Same as ICTriangleFalse, but false path rev condition.
      ICTriangleRev,   // Same as ICTriangle, but true pat