X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FRegionInfo.cpp;h=f59d267303276759d90cf1e11e580789fcc28f62;hb=5276bfeab1b7fc7266d9b089a85d04c1a347e369;hp=30f0d2f10d862e2d1b0b7bdcf7fc030a5927bafb;hpb=286c4dc355b8be6806081b23c3097485821c7642;p=oota-llvm.git

diff --git a/lib/Analysis/RegionInfo.cpp b/lib/Analysis/RegionInfo.cpp
index 30f0d2f10d8..f59d2673032 100644
--- a/lib/Analysis/RegionInfo.cpp
+++ b/lib/Analysis/RegionInfo.cpp
@@ -10,38 +10,45 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Analysis/RegionInfo.h"
-#include "llvm/Analysis/RegionIterator.h"
-
 #include "llvm/ADT/PostOrderIterator.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/RegionInfoImpl.h"
+#include "llvm/Analysis/RegionIterator.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
-#include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Assembly/Writer.h"
+#include <algorithm>
+#include <iterator>
+#include <set>
+#ifndef NDEBUG
+#include "llvm/Analysis/RegionPrinter.h"
+#endif
+
+using namespace llvm;
 
 #define DEBUG_TYPE "region"
-#include "llvm/Support/Debug.h"
 
-#include <set>
-#include <algorithm>
+namespace llvm {
+template class RegionBase<RegionTraits<Function>>;
+template class RegionNodeBase<RegionTraits<Function>>;
+template class RegionInfoBase<RegionTraits<Function>>;
+}
 
-using namespace llvm;
+STATISTIC(numRegions,       "The # of regions");
+STATISTIC(numSimpleRegions, "The # of simple regions");
 
 // Always verify if expensive checking is enabled.
-#ifdef XDEBUG
-static bool VerifyRegionInfo = true;
-#else
-static bool VerifyRegionInfo = false;
-#endif
 
 static cl::opt<bool,true>
-VerifyRegionInfoX("verify-region-info", cl::location(VerifyRegionInfo),
-                cl::desc("Verify region info (time consuming)"));
+VerifyRegionInfoX(
+  "verify-region-info",
+  cl::location(RegionInfoBase<RegionTraits<Function>>::VerifyRegionInfo),
+  cl::desc("Verify region info (time consuming)"));
 
-STATISTIC(numRegions,       "The # of regions");
-STATISTIC(numSimpleRegions, "The # of simple regions");
 
-static cl::opt<enum Region::PrintStyle> printStyle("print-region-style",
+static cl::opt<Region::PrintStyle, true> printStyleX("print-region-style",
+  cl::location(RegionInfo::printStyle),
   cl::Hidden,
   cl::desc("style of printing regions"),
   cl::values(
@@ -51,776 +58,116 @@ static cl::opt<enum Region::PrintStyle> printStyle("print-region-style",
     clEnumValN(Region::PrintRN, "rn",
                "print regions in detail with element_iterator"),
     clEnumValEnd));
-//===----------------------------------------------------------------------===//
-/// Region Implementation
-Region::Region(BasicBlock *Entry, BasicBlock *Exit, RegionInfo* RInfo,
-               DominatorTree *dt, Region *Parent)
-               : RegionNode(Parent, Entry, 1), RI(RInfo), DT(dt), exit(Exit) {}
-
-Region::~Region() {
-  // Free the cached nodes.
-  for (BBNodeMapT::iterator it = BBNodeMap.begin(),
-         ie = BBNodeMap.end(); it != ie; ++it)
-    delete it->second;
-
-  // Only clean the cache for this Region. Caches of child Regions will be
-  // cleaned when the child Regions are deleted.
-  BBNodeMap.clear();
-
-  for (iterator I = begin(), E = end(); I != E; ++I)
-    delete *I;
-}
-
-void Region::replaceEntry(BasicBlock *BB) {
-  entry.setPointer(BB);
-}
-
-void Region::replaceExit(BasicBlock *BB) {
-  assert(exit && "No exit to replace!");
-  exit = BB;
-}
-
-bool Region::contains(const BasicBlock *B) const {
-  BasicBlock *BB = const_cast<BasicBlock*>(B);
-
-  assert(DT->getNode(BB) && "BB not part of the dominance tree");
-
-  BasicBlock *entry = getEntry(), *exit = getExit();
-
-  // Toplevel region.
-  if (!exit)
-    return true;
-
-  return (DT->dominates(entry, BB)
-    && !(DT->dominates(exit, BB) && DT->dominates(entry, exit)));
-}
-
-bool Region::contains(const Loop *L) const {
-  // BBs that are not part of any loop are element of the Loop
-  // described by the NULL pointer. This loop is not part of any region,
-  // except if the region describes the whole function.
-  if (L == 0)
-    return getExit() == 0;
-
-  if (!contains(L->getHeader()))
-    return false;
-
-  SmallVector<BasicBlock *, 8> ExitingBlocks;
-  L->getExitingBlocks(ExitingBlocks);
-
-  for (SmallVectorImpl<BasicBlock*>::iterator BI = ExitingBlocks.begin(),
-       BE = ExitingBlocks.end(); BI != BE; ++BI)
-    if (!contains(*BI))
-      return false;
-
-  return true;
-}
-
-Loop *Region::outermostLoopInRegion(Loop *L) const {
-  if (!contains(L))
-    return 0;
-
-  while (L && contains(L->getParentLoop())) {
-    L = L->getParentLoop();
-  }
-
-  return L;
-}
-
-Loop *Region::outermostLoopInRegion(LoopInfo *LI, BasicBlock* BB) const {
-  assert(LI && BB && "LI and BB cannot be null!");
-  Loop *L = LI->getLoopFor(BB);
-  return outermostLoopInRegion(L);
-}
-
-BasicBlock *Region::getEnteringBlock() const {
-  BasicBlock *entry = getEntry();
-  BasicBlock *Pred;
-  BasicBlock *enteringBlock = 0;
-
-  for (pred_iterator PI = pred_begin(entry), PE = pred_end(entry); PI != PE;
-       ++PI) {
-    Pred = *PI;
-    if (DT->getNode(Pred) && !contains(Pred)) {
-      if (enteringBlock)
-        return 0;
-
-      enteringBlock = Pred;
-    }
-  }
-
-  return enteringBlock;
-}
-
-BasicBlock *Region::getExitingBlock() const {
-  BasicBlock *exit = getExit();
-  BasicBlock *Pred;
-  BasicBlock *exitingBlock = 0;
-
-  if (!exit)
-    return 0;
-
-  for (pred_iterator PI = pred_begin(exit), PE = pred_end(exit); PI != PE;
-       ++PI) {
-    Pred = *PI;
-    if (contains(Pred)) {
-      if (exitingBlock)
-        return 0;
-
-      exitingBlock = Pred;
-    }
-  }
-
-  return exitingBlock;
-}
-
-bool Region::isSimple() const {
-  return !isTopLevelRegion() && getEnteringBlock() && getExitingBlock();
-}
-
-std::string Region::getNameStr() const {
-  std::string exitName;
-  std::string entryName;
-
-  if (getEntry()->getName().empty()) {
-    raw_string_ostream OS(entryName);
-
-    WriteAsOperand(OS, getEntry(), false);
-  } else
-    entryName = getEntry()->getName();
-
-  if (getExit()) {
-    if (getExit()->getName().empty()) {
-      raw_string_ostream OS(exitName);
-
-      WriteAsOperand(OS, getExit(), false);
-    } else
-      exitName = getExit()->getName();
-  } else
-    exitName = "<Function Return>";
-
-  return entryName + " => " + exitName;
-}
-
-void Region::verifyBBInRegion(BasicBlock *BB) const {
-  if (!contains(BB))
-    llvm_unreachable("Broken region found!");
-
-  BasicBlock *entry = getEntry(), *exit = getExit();
-
-  for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
-    if (!contains(*SI) && exit != *SI)
-      llvm_unreachable("Broken region found!");
-
-  if (entry != BB)
-    for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB); SI != SE; ++SI)
-      if (!contains(*SI))
-        llvm_unreachable("Broken region found!");
-}
-
-void Region::verifyWalk(BasicBlock *BB, std::set<BasicBlock*> *visited) const {
-  BasicBlock *exit = getExit();
-
-  visited->insert(BB);
-
-  verifyBBInRegion(BB);
-
-  for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
-    if (*SI != exit && visited->find(*SI) == visited->end())
-        verifyWalk(*SI, visited);
-}
-
-void Region::verifyRegion() const {
-  // Only do verification when user wants to, otherwise this expensive
-  // check will be invoked by PassManager.
-  if (!VerifyRegionInfo) return;
-
-  std::set<BasicBlock*> visited;
-  verifyWalk(getEntry(), &visited);
-}
-
-void Region::verifyRegionNest() const {
-  for (Region::const_iterator RI = begin(), RE = end(); RI != RE; ++RI)
-    (*RI)->verifyRegionNest();
-
-  verifyRegion();
-}
-
-Region::element_iterator Region::element_begin() {
-  return GraphTraits<Region*>::nodes_begin(this);
-}
-
-Region::element_iterator Region::element_end() {
-  return GraphTraits<Region*>::nodes_end(this);
-}
-
-Region::const_element_iterator Region::element_begin() const {
-  return GraphTraits<const Region*>::nodes_begin(this);
-}
-
-Region::const_element_iterator Region::element_end() const {
-  return GraphTraits<const Region*>::nodes_end(this);
-}
-
-Region* Region::getSubRegionNode(BasicBlock *BB) const {
-  Region *R = RI->getRegionFor(BB);
-
-  if (!R || R == this)
-    return 0;
-
-  // If we pass the BB out of this region, that means our code is broken.
-  assert(contains(R) && "BB not in current region!");
-
-  while (contains(R->getParent()) && R->getParent() != this)
-    R = R->getParent();
-
-  if (R->getEntry() != BB)
-    return 0;
-
-  return R;
-}
-
-RegionNode* Region::getBBNode(BasicBlock *BB) const {
-  assert(contains(BB) && "Can get BB node out of this region!");
-
-  BBNodeMapT::const_iterator at = BBNodeMap.find(BB);
-
-  if (at != BBNodeMap.end())
-    return at->second;
-
-  RegionNode *NewNode = new RegionNode(const_cast<Region*>(this), BB);
-  BBNodeMap.insert(std::make_pair(BB, NewNode));
-  return NewNode;
-}
-
-RegionNode* Region::getNode(BasicBlock *BB) const {
-  assert(contains(BB) && "Can get BB node out of this region!");
-  if (Region* Child = getSubRegionNode(BB))
-    return Child->getNode();
-
-  return getBBNode(BB);
-}
-
-void Region::transferChildrenTo(Region *To) {
-  for (iterator I = begin(), E = end(); I != E; ++I) {
-    (*I)->parent = To;
-    To->children.push_back(*I);
-  }
-  children.clear();
-}
-
-void Region::addSubRegion(Region *SubRegion, bool moveChildren) {
-  assert(SubRegion->parent == 0 && "SubRegion already has a parent!");
-  assert(std::find(begin(), end(), SubRegion) == children.end()
-         && "Subregion already exists!");
-
-  SubRegion->parent = this;
-  children.push_back(SubRegion);
-
-  if (!moveChildren)
-    return;
-
-  assert(SubRegion->children.size() == 0
-         && "SubRegions that contain children are not supported");
-
-  for (element_iterator I = element_begin(), E = element_end(); I != E; ++I)
-    if (!(*I)->isSubRegion()) {
-      BasicBlock *BB = (*I)->getNodeAs<BasicBlock>();
-
-      if (SubRegion->contains(BB))
-        RI->setRegionFor(BB, SubRegion);
-    }
-
-  std::vector<Region*> Keep;
-  for (iterator I = begin(), E = end(); I != E; ++I)
-    if (SubRegion->contains(*I) && *I != SubRegion) {
-      SubRegion->children.push_back(*I);
-      (*I)->parent = SubRegion;
-    } else
-      Keep.push_back(*I);
-
-  children.clear();
-  children.insert(children.begin(), Keep.begin(), Keep.end());
-}
-
 
-Region *Region::removeSubRegion(Region *Child) {
-  assert(Child->parent == this && "Child is not a child of this region!");
-  Child->parent = 0;
-  RegionSet::iterator I = std::find(children.begin(), children.end(), Child);
-  assert(I != children.end() && "Region does not exit. Unable to remove.");
-  children.erase(children.begin()+(I-begin()));
-  return Child;
-}
-
-unsigned Region::getDepth() const {
-  unsigned Depth = 0;
-
-  for (Region *R = parent; R != 0; R = R->parent)
-    ++Depth;
-
-  return Depth;
-}
-
-Region *Region::getExpandedRegion() const {
-  unsigned NumSuccessors = exit->getTerminator()->getNumSuccessors();
-
-  if (NumSuccessors == 0)
-    return NULL;
-
-  for (pred_iterator PI = pred_begin(getExit()), PE = pred_end(getExit());
-       PI != PE; ++PI)
-    if (!DT->dominates(getEntry(), *PI))
-      return NULL;
-
-  Region *R = RI->getRegionFor(exit);
-
-  if (R->getEntry() != exit) {
-    if (exit->getTerminator()->getNumSuccessors() == 1)
-      return new Region(getEntry(), *succ_begin(exit), RI, DT);
-    else
-      return NULL;
-  }
-
-  while (R->getParent() && R->getParent()->getEntry() == exit)
-    R = R->getParent();
-
-  if (!DT->dominates(getEntry(), R->getExit()))
-    for (pred_iterator PI = pred_begin(getExit()), PE = pred_end(getExit());
-         PI != PE; ++PI)
-    if (!DT->dominates(R->getExit(), *PI))
-      return NULL;
-
-  return new Region(getEntry(), R->getExit(), RI, DT);
-}
-
-void Region::print(raw_ostream &OS, bool print_tree, unsigned level,
-                   enum PrintStyle Style) const {
-  if (print_tree)
-    OS.indent(level*2) << "[" << level << "] " << getNameStr();
-  else
-    OS.indent(level*2) << getNameStr();
 
-  OS << "\n";
-
-
-  if (Style != PrintNone) {
-    OS.indent(level*2) << "{\n";
-    OS.indent(level*2 + 2);
-
-    if (Style == PrintBB) {
-      for (const_block_iterator I = block_begin(), E = block_end(); I != E; ++I)
-        OS << (*I)->getName() << ", "; // TODO: remove the last ","
-    } else if (Style == PrintRN) {
-      for (const_element_iterator I = element_begin(), E = element_end(); I!=E; ++I)
-        OS << **I << ", "; // TODO: remove the last ",
-    }
-
-    OS << "\n";
-  }
+//===----------------------------------------------------------------------===//
+// Region implementation
+//
 
-  if (print_tree)
-    for (const_iterator RI = begin(), RE = end(); RI != RE; ++RI)
-      (*RI)->print(OS, print_tree, level+1, Style);
+Region::Region(BasicBlock *Entry, BasicBlock *Exit,
+               RegionInfo* RI,
+               DominatorTree *DT, Region *Parent) :
+  RegionBase<RegionTraits<Function>>(Entry, Exit, RI, DT, Parent) {
 
-  if (Style != PrintNone)
-    OS.indent(level*2) << "} \n";
 }
 
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-void Region::dump() const {
-  print(dbgs(), true, getDepth(), printStyle.getValue());
-}
-#endif
-
-void Region::clearNodeCache() {
-  // Free the cached nodes.
-  for (BBNodeMapT::iterator I = BBNodeMap.begin(),
-       IE = BBNodeMap.end(); I != IE; ++I)
-    delete I->second;
-
-  BBNodeMap.clear();
-  for (Region::iterator RI = begin(), RE = end(); RI != RE; ++RI)
-    (*RI)->clearNodeCache();
-}
+Region::~Region() { }
 
 //===----------------------------------------------------------------------===//
 // RegionInfo implementation
 //
 
-bool RegionInfo::isCommonDomFrontier(BasicBlock *BB, BasicBlock *entry,
-                                     BasicBlock *exit) const {
-  for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
-    BasicBlock *P = *PI;
-    if (DT->dominates(entry, P) && !DT->dominates(exit, P))
-      return false;
-  }
-  return true;
-}
+RegionInfo::RegionInfo() :
+  RegionInfoBase<RegionTraits<Function>>() {
 
-bool RegionInfo::isRegion(BasicBlock *entry, BasicBlock *exit) const {
-  assert(entry && exit && "entry and exit must not be null!");
-  typedef DominanceFrontier::DomSetType DST;
-
-  DST *entrySuccs = &DF->find(entry)->second;
-
-  // Exit is the header of a loop that contains the entry. In this case,
-  // the dominance frontier must only contain the exit.
-  if (!DT->dominates(entry, exit)) {
-    for (DST::iterator SI = entrySuccs->begin(), SE = entrySuccs->end();
-         SI != SE; ++SI)
-      if (*SI != exit && *SI != entry)
-        return false;
-
-    return true;
-  }
-
-  DST *exitSuccs = &DF->find(exit)->second;
-
-  // Do not allow edges leaving the region.
-  for (DST::iterator SI = entrySuccs->begin(), SE = entrySuccs->end();
-       SI != SE; ++SI) {
-    if (*SI == exit || *SI == entry)
-      continue;
-    if (exitSuccs->find(*SI) == exitSuccs->end())
-      return false;
-    if (!isCommonDomFrontier(*SI, entry, exit))
-      return false;
-  }
-
-  // Do not allow edges pointing into the region.
-  for (DST::iterator SI = exitSuccs->begin(), SE = exitSuccs->end();
-       SI != SE; ++SI)
-    if (DT->properlyDominates(entry, *SI) && *SI != exit)
-      return false;
-
-
-  return true;
-}
-
-void RegionInfo::insertShortCut(BasicBlock *entry, BasicBlock *exit,
-                             BBtoBBMap *ShortCut) const {
-  assert(entry && exit && "entry and exit must not be null!");
-
-  BBtoBBMap::iterator e = ShortCut->find(exit);
-
-  if (e == ShortCut->end())
-    // No further region at exit available.
-    (*ShortCut)[entry] = exit;
-  else {
-    // We found a region e that starts at exit. Therefore (entry, e->second)
-    // is also a region, that is larger than (entry, exit). Insert the
-    // larger one.
-    BasicBlock *BB = e->second;
-    (*ShortCut)[entry] = BB;
-  }
-}
-
-DomTreeNode* RegionInfo::getNextPostDom(DomTreeNode* N,
-                                        BBtoBBMap *ShortCut) const {
-  BBtoBBMap::iterator e = ShortCut->find(N->getBlock());
-
-  if (e == ShortCut->end())
-    return N->getIDom();
-
-  return PDT->getNode(e->second)->getIDom();
 }
 
-bool RegionInfo::isTrivialRegion(BasicBlock *entry, BasicBlock *exit) const {
-  assert(entry && exit && "entry and exit must not be null!");
-
-  unsigned num_successors = succ_end(entry) - succ_begin(entry);
-
-  if (num_successors <= 1 && exit == *(succ_begin(entry)))
-    return true;
+RegionInfo::~RegionInfo() {
 
-  return false;
 }
 
 void RegionInfo::updateStatistics(Region *R) {
   ++numRegions;
 
   // TODO: Slow. Should only be enabled if -stats is used.
-  if (R->isSimple()) ++numSimpleRegions;
+  if (R->isSimple())
+    ++numSimpleRegions;
 }
 
-Region *RegionInfo::createRegion(BasicBlock *entry, BasicBlock *exit) {
-  assert(entry && exit && "entry and exit must not be null!");
-
-  if (isTrivialRegion(entry, exit))
-    return 0;
-
-  Region *region = new Region(entry, exit, this, DT);
-  BBtoRegion.insert(std::make_pair(entry, region));
-
- #ifdef XDEBUG
-    region->verifyRegion();
- #else
-    DEBUG(region->verifyRegion());
- #endif
-
-  updateStatistics(region);
-  return region;
-}
-
-void RegionInfo::findRegionsWithEntry(BasicBlock *entry, BBtoBBMap *ShortCut) {
-  assert(entry);
-
-  DomTreeNode *N = PDT->getNode(entry);
-
-  if (!N)
-    return;
-
-  Region *lastRegion= 0;
-  BasicBlock *lastExit = entry;
-
-  // As only a BasicBlock that postdominates entry can finish a region, walk the
-  // post dominance tree upwards.
-  while ((N = getNextPostDom(N, ShortCut))) {
-    BasicBlock *exit = N->getBlock();
+void RegionInfo::recalculate(Function &F, DominatorTree *DT_,
+                             PostDominatorTree *PDT_, DominanceFrontier *DF_) {
+  DT = DT_;
+  PDT = PDT_;
+  DF = DF_;
 
-    if (!exit)
-      break;
-
-    if (isRegion(entry, exit)) {
-      Region *newRegion = createRegion(entry, exit);
-
-      if (lastRegion)
-        newRegion->addSubRegion(lastRegion);
-
-      lastRegion = newRegion;
-      lastExit = exit;
-    }
-
-    // This can never be a region, so stop the search.
-    if (!DT->dominates(entry, exit))
-      break;
-  }
-
-  // Tried to create regions from entry to lastExit.  Next time take a
-  // shortcut from entry to lastExit.
-  if (lastExit != entry)
-    insertShortCut(entry, lastExit, ShortCut);
-}
-
-void RegionInfo::scanForRegions(Function &F, BBtoBBMap *ShortCut) {
-  BasicBlock *entry = &(F.getEntryBlock());
-  DomTreeNode *N = DT->getNode(entry);
-
-  // Iterate over the dominance tree in post order to start with the small
-  // regions from the bottom of the dominance tree.  If the small regions are
-  // detected first, detection of bigger regions is faster, as we can jump
-  // over the small regions.
-  for (po_iterator<DomTreeNode*> FI = po_begin(N), FE = po_end(N); FI != FE;
-    ++FI) {
-    findRegionsWithEntry(FI->getBlock(), ShortCut);
-  }
-}
-
-Region *RegionInfo::getTopMostParent(Region *region) {
-  while (region->parent)
-    region = region->getParent();
-
-  return region;
+  TopLevelRegion = new Region(&F.getEntryBlock(), nullptr,
+                              this, DT, nullptr);
+  updateStatistics(TopLevelRegion);
+  calculate(F);
 }
 
-void RegionInfo::buildRegionsTree(DomTreeNode *N, Region *region) {
-  BasicBlock *BB = N->getBlock();
-
-  // Passed region exit
-  while (BB == region->getExit())
-    region = region->getParent();
+#ifndef NDEBUG
+void RegionInfo::view() { viewRegion(this); }
 
-  BBtoRegionMap::iterator it = BBtoRegion.find(BB);
+void RegionInfo::viewOnly() { viewRegionOnly(this); }
+#endif
 
-  // This basic block is a start block of a region. It is already in the
-  // BBtoRegion relation. Only the child basic blocks have to be updated.
-  if (it != BBtoRegion.end()) {
-    Region *newRegion = it->second;
-    region->addSubRegion(getTopMostParent(newRegion));
-    region = newRegion;
-  } else {
-    BBtoRegion[BB] = region;
-  }
+//===----------------------------------------------------------------------===//
+// RegionInfoPass implementation
+//
 
-  for (DomTreeNode::iterator CI = N->begin(), CE = N->end(); CI != CE; ++CI)
-    buildRegionsTree(*CI, region);
+RegionInfoPass::RegionInfoPass() : FunctionPass(ID) {
+  initializeRegionInfoPassPass(*PassRegistry::getPassRegistry());
 }
 
-void RegionInfo::releaseMemory() {
-  BBtoRegion.clear();
-  if (TopLevelRegion)
-    delete TopLevelRegion;
-  TopLevelRegion = 0;
-}
+RegionInfoPass::~RegionInfoPass() {
 
-RegionInfo::RegionInfo() : FunctionPass(ID) {
-  initializeRegionInfoPass(*PassRegistry::getPassRegistry());
-  TopLevelRegion = 0;
 }
 
-RegionInfo::~RegionInfo() {
+bool RegionInfoPass::runOnFunction(Function &F) {
   releaseMemory();
-}
 
-void RegionInfo::Calculate(Function &F) {
-  // ShortCut a function where for every BB the exit of the largest region
-  // starting with BB is stored. These regions can be threated as single BBS.
-  // This improves performance on linear CFGs.
-  BBtoBBMap ShortCut;
+  auto DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+  auto PDT = &getAnalysis<PostDominatorTree>();
+  auto DF = &getAnalysis<DominanceFrontier>();
 
-  scanForRegions(F, &ShortCut);
-  BasicBlock *BB = &F.getEntryBlock();
-  buildRegionsTree(DT->getNode(BB), TopLevelRegion);
+  RI.recalculate(F, DT, PDT, DF);
+  return false;
 }
 
-bool RegionInfo::runOnFunction(Function &F) {
-  releaseMemory();
-
-  DT = &getAnalysis<DominatorTree>();
-  PDT = &getAnalysis<PostDominatorTree>();
-  DF = &getAnalysis<DominanceFrontier>();
-
-  TopLevelRegion = new Region(&F.getEntryBlock(), 0, this, DT, 0);
-  updateStatistics(TopLevelRegion);
-
-  Calculate(F);
+void RegionInfoPass::releaseMemory() {
+  RI.releaseMemory();
+}
 
-  return false;
+void RegionInfoPass::verifyAnalysis() const {
+    RI.verifyAnalysis();
 }
 
-void RegionInfo::getAnalysisUsage(AnalysisUsage &AU) const {
+void RegionInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesAll();
-  AU.addRequiredTransitive<DominatorTree>();
+  AU.addRequiredTransitive<DominatorTreeWrapperPass>();
   AU.addRequired<PostDominatorTree>();
   AU.addRequired<DominanceFrontier>();
 }
 
-void RegionInfo::print(raw_ostream &OS, const Module *) const {
-  OS << "Region tree:\n";
-  TopLevelRegion->print(OS, true, 0, printStyle.getValue());
-  OS << "End region tree\n";
-}
-
-void RegionInfo::verifyAnalysis() const {
-  // Only do verification when user wants to, otherwise this expensive check
-  // will be invoked by PMDataManager::verifyPreservedAnalysis when
-  // a regionpass (marked PreservedAll) finish.
-  if (!VerifyRegionInfo) return;
-
-  TopLevelRegion->verifyRegionNest();
-}
-
-// Region pass manager support.
-Region *RegionInfo::getRegionFor(BasicBlock *BB) const {
-  BBtoRegionMap::const_iterator I=
-    BBtoRegion.find(BB);
-  return I != BBtoRegion.end() ? I->second : 0;
-}
-
-void RegionInfo::setRegionFor(BasicBlock *BB, Region *R) {
-  BBtoRegion[BB] = R;
-}
-
-Region *RegionInfo::operator[](BasicBlock *BB) const {
-  return getRegionFor(BB);
-}
-
-BasicBlock *RegionInfo::getMaxRegionExit(BasicBlock *BB) const {
-  BasicBlock *Exit = NULL;
-
-  while (true) {
-    // Get largest region that starts at BB.
-    Region *R = getRegionFor(BB);
-    while (R && R->getParent() && R->getParent()->getEntry() == BB)
-      R = R->getParent();
-
-    // Get the single exit of BB.
-    if (R && R->getEntry() == BB)
-      Exit = R->getExit();
-    else if (++succ_begin(BB) == succ_end(BB))
-      Exit = *succ_begin(BB);
-    else // No single exit exists.
-      return Exit;
-
-    // Get largest region that starts at Exit.
-    Region *ExitR = getRegionFor(Exit);
-    while (ExitR && ExitR->getParent()
-           && ExitR->getParent()->getEntry() == Exit)
-      ExitR = ExitR->getParent();
-
-    for (pred_iterator PI = pred_begin(Exit), PE = pred_end(Exit); PI != PE;
-         ++PI)
-      if (!R->contains(*PI) && !ExitR->contains(*PI))
-        break;
-
-    // This stops infinite cycles.
-    if (DT->dominates(Exit, BB))
-      break;
-
-    BB = Exit;
-  }
-
-  return Exit;
-}
-
-Region*
-RegionInfo::getCommonRegion(Region *A, Region *B) const {
-  assert (A && B && "One of the Regions is NULL");
-
-  if (A->contains(B)) return A;
-
-  while (!B->contains(A))
-    B = B->getParent();
-
-  return B;
-}
-
-Region*
-RegionInfo::getCommonRegion(SmallVectorImpl<Region*> &Regions) const {
-  Region* ret = Regions.back();
-  Regions.pop_back();
-
-  for (SmallVectorImpl<Region*>::const_iterator I = Regions.begin(),
-       E = Regions.end(); I != E; ++I)
-      ret = getCommonRegion(ret, *I);
-
-  return ret;
+void RegionInfoPass::print(raw_ostream &OS, const Module *) const {
+  RI.print(OS);
 }
 
-Region*
-RegionInfo::getCommonRegion(SmallVectorImpl<BasicBlock*> &BBs) const {
-  Region* ret = getRegionFor(BBs.back());
-  BBs.pop_back();
-
-  for (SmallVectorImpl<BasicBlock*>::const_iterator I = BBs.begin(),
-       E = BBs.end(); I != E; ++I)
-      ret = getCommonRegion(ret, getRegionFor(*I));
-
-  return ret;
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void RegionInfoPass::dump() const {
+  RI.dump();
 }
+#endif
 
-void RegionInfo::splitBlock(BasicBlock* NewBB, BasicBlock *OldBB)
-{
-  Region *R = getRegionFor(OldBB);
-
-  setRegionFor(NewBB, R);
-
-  while (R->getEntry() == OldBB && !R->isTopLevelRegion()) {
-    R->replaceEntry(NewBB);
-    R = R->getParent();
-  }
-
-  setRegionFor(OldBB, R);
-}
+char RegionInfoPass::ID = 0;
 
-char RegionInfo::ID = 0;
-INITIALIZE_PASS_BEGIN(RegionInfo, "regions",
+INITIALIZE_PASS_BEGIN(RegionInfoPass, "regions",
                 "Detect single entry single exit regions", true, true)
-INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(PostDominatorTree)
 INITIALIZE_PASS_DEPENDENCY(DominanceFrontier)
-INITIALIZE_PASS_END(RegionInfo, "regions",
+INITIALIZE_PASS_END(RegionInfoPass, "regions",
                 "Detect single entry single exit regions", true, true)
 
 // Create methods available outside of this file, to use them
@@ -829,7 +176,7 @@ INITIALIZE_PASS_END(RegionInfo, "regions",
 
 namespace llvm {
   FunctionPass *createRegionInfoPass() {
-    return new RegionInfo();
+    return new RegionInfoPass();
   }
 }