Start the process of making MachineLoopInfo possible by templating Loop.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44097 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 350 insertions, 49 deletions

diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h
index 86dc571..32115ae 100644
--- a/include/llvm/Analysis/LoopInfo.h
+++ b/include/llvm/Analysis/LoopInfo.h
@@ -31,8 +31,22 @@
 #define LLVM_ANALYSIS_LOOP_INFO_H
 
 #include "llvm/Pass.h"
+#include "llvm/Constants.h"
+#include "llvm/Instructions.h"
 #include "llvm/ADT/GraphTraits.h"
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/Support/Streams.h"
+#include <algorithm>
+#include <ostream>
+
+template<typename T>
+static void RemoveFromVector(std::vector<T*> &V, T *N) {
+  typename std::vector<T*>::iterator I = std::find(V.begin(), V.end(), N);
+  assert(I != V.end() && "N is not in this list!");
+  V.erase(I);
+}
 
 namespace llvm {
 
@@ -42,64 +56,88 @@ class PHINode;
 class Instruction;
 
 //===----------------------------------------------------------------------===//
-/// Loop class - Instances of this class are used to represent loops that are
+/// LoopBase class - Instances of this class are used to represent loops that are
 /// detected in the flow graph
 ///
-class Loop {
-  Loop *ParentLoop;
-  std::vector<Loop*> SubLoops;       // Loops contained entirely within this one
-  std::vector<BasicBlock*> Blocks;   // First entry is the header node
-
-  Loop(const Loop &);                  // DO NOT IMPLEMENT
-  const Loop &operator=(const Loop &); // DO NOT IMPLEMENT
+template<class BlockT>
+class LoopBase {
+  LoopBase<BlockT> *ParentLoop;
+  std::vector<LoopBase<BlockT>*> SubLoops;       // Loops contained entirely within this one
+  std::vector<BlockT*> Blocks;   // First entry is the header node
+
+  LoopBase(const LoopBase<BlockT> &);                  // DO NOT IMPLEMENT
+  const LoopBase<BlockT> &operator=(const LoopBase<BlockT> &); // DO NOT IMPLEMENT
 public:
   /// Loop ctor - This creates an empty loop.
-  Loop() : ParentLoop(0) {}
-  ~Loop() {
+  LoopBase() : ParentLoop(0) {}
+  ~LoopBase() {
     for (unsigned i = 0, e = SubLoops.size(); i != e; ++i)
       delete SubLoops[i];
   }
 
   unsigned getLoopDepth() const {
     unsigned D = 0;
-    for (const Loop *CurLoop = this; CurLoop; CurLoop = CurLoop->ParentLoop)
+    for (const LoopBase<BlockT> *CurLoop = this; CurLoop;
+         CurLoop = CurLoop->ParentLoop)
       ++D;
     return D;
   }
-  BasicBlock *getHeader() const { return Blocks.front(); }
-  Loop *getParentLoop() const { return ParentLoop; }
+  BlockT *getHeader() const { return Blocks.front(); }
+  LoopBase<BlockT> *getParentLoop() const { return ParentLoop; }
 
   /// contains - Return true of the specified basic block is in this loop
   ///
-  bool contains(const BasicBlock *BB) const;
+  bool contains(const BlockT *BB) const {
+    return std::find(Blocks.begin(), Blocks.end(), BB) != Blocks.end();
+  }
 
   /// iterator/begin/end - Return the loops contained entirely within this loop.
   ///
-  const std::vector<Loop*> &getSubLoops() const { return SubLoops; }
-  typedef std::vector<Loop*>::const_iterator iterator;
+  const std::vector<LoopBase<BlockT>*> &getSubLoops() const { return SubLoops; }
+  typedef typename std::vector<LoopBase<BlockT>*>::const_iterator iterator;
   iterator begin() const { return SubLoops.begin(); }
   iterator end() const { return SubLoops.end(); }
   bool empty() const { return SubLoops.empty(); }
 
   /// getBlocks - Get a list of the basic blocks which make up this loop.
   ///
-  const std::vector<BasicBlock*> &getBlocks() const { return Blocks; }
-  typedef std::vector<BasicBlock*>::const_iterator block_iterator;
+  const std::vector<BlockT*> &getBlocks() const { return Blocks; }
+  typedef typename std::vector<BlockT*>::const_iterator block_iterator;
   block_iterator block_begin() const { return Blocks.begin(); }
   block_iterator block_end() const { return Blocks.end(); }
 
   /// isLoopExit - True if terminator in the block can branch to another block
   /// that is outside of the current loop.
   ///
-  bool isLoopExit(const BasicBlock *BB) const;
+  bool isLoopExit(const BlockT *BB) const {
+    for (succ_const_iterator SI = succ_begin(BB), SE = succ_end(BB);
+         SI != SE; ++SI) {
+      if (!contains(*SI))
+        return true;
+    }
+    return false;
+  }
 
   /// getNumBackEdges - Calculate the number of back edges to the loop header
   ///
-  unsigned getNumBackEdges() const;
+  unsigned getNumBackEdges() const {
+    unsigned NumBackEdges = 0;
+    BlockT *H = getHeader();
+
+    for (pred_iterator I = pred_begin(H), E = pred_end(H); I != E; ++I)
+      if (contains(*I))
+        ++NumBackEdges;
+
+    return NumBackEdges;
+  }
 
   /// isLoopInvariant - Return true if the specified value is loop invariant
   ///
-  bool isLoopInvariant(Value *V) const;
+  bool isLoopInvariant(Value *V) const {
+    if (Instruction *I = dyn_cast<Instruction>(V))
+      return !contains(I->getParent());
+    return true;  // All non-instructions are loop invariant
+  }
 
   //===--------------------------------------------------------------------===//
   // APIs for simple analysis of the loop.
@@ -113,18 +151,91 @@ public:
   /// outside of the loop.  These are the blocks _inside of the current loop_
   /// which branch out.  The returned list is always unique.
   ///
-  void getExitingBlocks(SmallVectorImpl<BasicBlock *> &Blocks) const;
+  void getExitingBlocks(SmallVectorImpl<BlockT *> &ExitingBlocks) const {
+    // Sort the blocks vector so that we can use binary search to do quick
+    // lookups.
+    SmallVector<BlockT*, 128> LoopBBs(block_begin(), block_end());
+    std::sort(LoopBBs.begin(), LoopBBs.end());
+
+    for (typename std::vector<BlockT*>::const_iterator BI = Blocks.begin(),
+         BE = Blocks.end(); BI != BE; ++BI)
+      for (succ_iterator I = succ_begin(*BI), E = succ_end(*BI); I != E; ++I)
+        if (!std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I)) {
+          // Not in current loop? It must be an exit block.
+          ExitingBlocks.push_back(*BI);
+          break;
+        }
+  }
 
   /// getExitBlocks - Return all of the successor blocks of this loop.  These
   /// are the blocks _outside of the current loop_ which are branched to.
   ///
-  void getExitBlocks(SmallVectorImpl<BasicBlock* > &Blocks) const;
+  void getExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const {
+    // Sort the blocks vector so that we can use binary search to do quick
+    // lookups.
+    SmallVector<BlockT*, 128> LoopBBs(block_begin(), block_end());
+    std::sort(LoopBBs.begin(), LoopBBs.end());
+
+    for (typename std::vector<BlockT*>::const_iterator BI = Blocks.begin(),
+         BE = Blocks.end(); BI != BE; ++BI)
+      for (succ_iterator I = succ_begin(*BI), E = succ_end(*BI); I != E; ++I)
+        if (!std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I))
+          // Not in current loop? It must be an exit block.
+          ExitBlocks.push_back(*I);
+  }
 
   /// getUniqueExitBlocks - Return all unique successor blocks of this loop. 
   /// These are the blocks _outside of the current loop_ which are branched to.
   /// This assumes that loop is in canonical form.
   ///
-  void getUniqueExitBlocks(SmallVectorImpl<BasicBlock*> &ExitBlocks) const;
+  void getUniqueExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const {
+    // Sort the blocks vector so that we can use binary search to do quick
+    // lookups.
+    SmallVector<BlockT*, 128> LoopBBs(block_begin(), block_end());
+    std::sort(LoopBBs.begin(), LoopBBs.end());
+
+    std::vector<BlockT*> switchExitBlocks;  
+
+    for (typename std::vector<BlockT*>::const_iterator BI = Blocks.begin(),
+         BE = Blocks.end(); BI != BE; ++BI) {
+
+      BlockT *current = *BI;
+      switchExitBlocks.clear();
+
+      for (succ_iterator I = succ_begin(*BI), E = succ_end(*BI); I != E; ++I) {
+        if (std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I))
+      // If block is inside the loop then it is not a exit block.
+          continue;
+
+        pred_iterator PI = pred_begin(*I);
+        BlockT *firstPred = *PI;
+
+        // If current basic block is this exit block's first predecessor
+        // then only insert exit block in to the output ExitBlocks vector.
+        // This ensures that same exit block is not inserted twice into
+        // ExitBlocks vector.
+        if (current != firstPred) 
+          continue;
+
+        // If a terminator has more then two successors, for example SwitchInst,
+        // then it is possible that there are multiple edges from current block 
+        // to one exit block. 
+        if (current->getTerminator()->getNumSuccessors() <= 2) {
+          ExitBlocks.push_back(*I);
+          continue;
+        }
+
+        // In case of multiple edges from current block to exit block, collect
+        // only one edge in ExitBlocks. Use switchExitBlocks to keep track of
+        // duplicate edges.
+        if (std::find(switchExitBlocks.begin(), switchExitBlocks.end(), *I) 
+            == switchExitBlocks.end()) {
+          switchExitBlocks.push_back(*I);
+          ExitBlocks.push_back(*I);
+        }
+      }
+    }
+  }
 
   /// getLoopPreheader - If there is a preheader for this loop, return it.  A
   /// loop has a preheader if there is only one edge to the header of the loop
@@ -133,36 +244,162 @@ public:
   ///
   /// This method returns null if there is no preheader for the loop.
   ///
-  BasicBlock *getLoopPreheader() const;
+  BlockT *getLoopPreheader() const {
+    // Keep track of nodes outside the loop branching to the header...
+    BlockT *Out = 0;
+
+    // Loop over the predecessors of the header node...
+    BlockT *Header = getHeader();
+    for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
+         PI != PE; ++PI)
+      if (!contains(*PI)) {     // If the block is not in the loop...
+        if (Out && Out != *PI)
+          return 0;             // Multiple predecessors outside the loop
+        Out = *PI;
+      }
+
+    // Make sure there is only one exit out of the preheader.
+    assert(Out && "Header of loop has no predecessors from outside loop?");
+    succ_iterator SI = succ_begin(Out);
+    ++SI;
+    if (SI != succ_end(Out))
+      return 0;  // Multiple exits from the block, must not be a preheader.
+
+    // If there is exactly one preheader, return it.  If there was zero, then Out
+    // is still null.
+    return Out;
+  }
 
   /// getLoopLatch - If there is a latch block for this loop, return it.  A
   /// latch block is the canonical backedge for a loop.  A loop header in normal
   /// form has two edges into it: one from a preheader and one from a latch
   /// block.
-  BasicBlock *getLoopLatch() const;
+  BlockT *getLoopLatch() const {
+    BlockT *Header = getHeader();
+    pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
+    if (PI == PE) return 0;  // no preds?
+
+    BlockT *Latch = 0;
+    if (contains(*PI))
+      Latch = *PI;
+    ++PI;
+    if (PI == PE) return 0;  // only one pred?
+
+    if (contains(*PI)) {
+      if (Latch) return 0;  // multiple backedges
+      Latch = *PI;
+    }
+    ++PI;
+    if (PI != PE) return 0;  // more than two preds
+
+    return Latch;
+  }
   
   /// getCanonicalInductionVariable - Check to see if the loop has a canonical
   /// induction variable: an integer recurrence that starts at 0 and increments
   /// by one each time through the loop.  If so, return the phi node that
   /// corresponds to it.
   ///
-  PHINode *getCanonicalInductionVariable() const;
+  PHINode *getCanonicalInductionVariable() const {
+    BlockT *H = getHeader();
+
+    BlockT *Incoming = 0, *Backedge = 0;
+    pred_iterator PI = pred_begin(H);
+    assert(PI != pred_end(H) && "Loop must have at least one backedge!");
+    Backedge = *PI++;
+    if (PI == pred_end(H)) return 0;  // dead loop
+    Incoming = *PI++;
+    if (PI != pred_end(H)) return 0;  // multiple backedges?
+
+    if (contains(Incoming)) {
+      if (contains(Backedge))
+        return 0;
+      std::swap(Incoming, Backedge);
+    } else if (!contains(Backedge))
+      return 0;
+
+    // Loop over all of the PHI nodes, looking for a canonical indvar.
+    for (typename BlockT::iterator I = H->begin(); isa<PHINode>(I); ++I) {
+      PHINode *PN = cast<PHINode>(I);
+      if (Instruction *Inc =
+          dyn_cast<Instruction>(PN->getIncomingValueForBlock(Backedge)))
+        if (Inc->getOpcode() == Instruction::Add && Inc->getOperand(0) == PN)
+          if (ConstantInt *CI = dyn_cast<ConstantInt>(Inc->getOperand(1)))
+            if (CI->equalsInt(1))
+              return PN;
+    }
+    return 0;
+  }
 
   /// getCanonicalInductionVariableIncrement - Return the LLVM value that holds
   /// the canonical induction variable value for the "next" iteration of the
   /// loop.  This always succeeds if getCanonicalInductionVariable succeeds.
   ///
-  Instruction *getCanonicalInductionVariableIncrement() const;
+  Instruction *getCanonicalInductionVariableIncrement() const {
+    if (PHINode *PN = getCanonicalInductionVariable()) {
+      bool P1InLoop = contains(PN->getIncomingBlock(1));
+      return cast<Instruction>(PN->getIncomingValue(P1InLoop));
+    }
+    return 0;
+  }
 
   /// getTripCount - Return a loop-invariant LLVM value indicating the number of
   /// times the loop will be executed.  Note that this means that the backedge
   /// of the loop executes N-1 times.  If the trip-count cannot be determined,
   /// this returns null.
   ///
-  Value *getTripCount() const;
+  Value *getTripCount() const {
+    // Canonical loops will end with a 'cmp ne I, V', where I is the incremented
+    // canonical induction variable and V is the trip count of the loop.
+    Instruction *Inc = getCanonicalInductionVariableIncrement();
+    if (Inc == 0) return 0;
+    PHINode *IV = cast<PHINode>(Inc->getOperand(0));
+
+    BlockT *BackedgeBlock =
+            IV->getIncomingBlock(contains(IV->getIncomingBlock(1)));
+
+    if (BranchInst *BI = dyn_cast<BranchInst>(BackedgeBlock->getTerminator()))
+      if (BI->isConditional()) {
+        if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition())) {
+          if (ICI->getOperand(0) == Inc)
+            if (BI->getSuccessor(0) == getHeader()) {
+              if (ICI->getPredicate() == ICmpInst::ICMP_NE)
+                return ICI->getOperand(1);
+            } else if (ICI->getPredicate() == ICmpInst::ICMP_EQ) {
+              return ICI->getOperand(1);
+            }
+        }
+      }
+
+    return 0;
+  }
   
   /// isLCSSAForm - Return true if the Loop is in LCSSA form
-  bool isLCSSAForm() const;
+  bool isLCSSAForm() const {
+    // Sort the blocks vector so that we can use binary search to do quick
+    // lookups.
+    SmallPtrSet<BlockT*, 16> LoopBBs(block_begin(), block_end());
+
+    for (block_iterator BI = block_begin(), E = block_end(); BI != E; ++BI) {
+      BlockT *BB = *BI;
+      for (typename BlockT::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
+        for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E;
+             ++UI) {
+          BlockT *UserBB = cast<Instruction>(*UI)->getParent();
+          if (PHINode *P = dyn_cast<PHINode>(*UI)) {
+            unsigned OperandNo = UI.getOperandNo();
+            UserBB = P->getIncomingBlock(OperandNo/2);
+          }
+
+          // Check the current block, as a fast-path.  Most values are used in the
+          // same block they are defined in.
+          if (UserBB != BB && !LoopBBs.count(UserBB))
+            return false;
+        }
+    }
+
+    return true;
+  }
 
   //===--------------------------------------------------------------------===//
   // APIs for updating loop information after changing the CFG
@@ -174,35 +411,56 @@ public:
   /// to the specified LoopInfo object as being in the current basic block.  It
   /// is not valid to replace the loop header with this method.
   ///
-  void addBasicBlockToLoop(BasicBlock *NewBB, LoopInfo &LI);
+  void addBasicBlockToLoop(BlockT *NewBB, LoopInfo &LI);
 
   /// replaceChildLoopWith - This is used when splitting loops up.  It replaces
   /// the OldChild entry in our children list with NewChild, and updates the
   /// parent pointer of OldChild to be null and the NewChild to be this loop.
   /// This updates the loop depth of the new child.
-  void replaceChildLoopWith(Loop *OldChild, Loop *NewChild);
+  void replaceChildLoopWith(LoopBase<BlockT> *OldChild,
+                            LoopBase<BlockT> *NewChild) {
+    assert(OldChild->ParentLoop == this && "This loop is already broken!");
+    assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!");
+    typename std::vector<LoopBase<BlockT>*>::iterator I =
+                          std::find(SubLoops.begin(), SubLoops.end(), OldChild);
+    assert(I != SubLoops.end() && "OldChild not in loop!");
+    *I = NewChild;
+    OldChild->ParentLoop = 0;
+    NewChild->ParentLoop = this;
+  }
 
   /// addChildLoop - Add the specified loop to be a child of this loop.  This
   /// updates the loop depth of the new child.
   ///
-  void addChildLoop(Loop *NewChild);
+  void addChildLoop(LoopBase<BlockT> *NewChild) {
+    assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!");
+    NewChild->ParentLoop = this;
+    SubLoops.push_back(NewChild);
+  }
 
   /// removeChildLoop - This removes the specified child from being a subloop of
   /// this loop.  The loop is not deleted, as it will presumably be inserted
   /// into another loop.
-  Loop *removeChildLoop(iterator OldChild);
+  LoopBase<BlockT> *removeChildLoop(iterator I) {
+    assert(I != SubLoops.end() && "Cannot remove end iterator!");
+    LoopBase<BlockT> *Child = *I;
+    assert(Child->ParentLoop == this && "Child is not a child of this loop!");
+    SubLoops.erase(SubLoops.begin()+(I-begin()));
+    Child->ParentLoop = 0;
+    return Child;
+  }
 
   /// addBlockEntry - This adds a basic block directly to the basic block list.
   /// This should only be used by transformations that create new loops.  Other
   /// transformations should use addBasicBlockToLoop.
-  void addBlockEntry(BasicBlock *BB) {
+  void addBlockEntry(BlockT *BB) {
     Blocks.push_back(BB);
   }
 
   /// moveToHeader - This method is used to move BB (which must be part of this
   /// loop) to be the loop header of the loop (the block that dominates all
   /// others).
-  void moveToHeader(BasicBlock *BB) {
+  void moveToHeader(BlockT *BB) {
     if (Blocks[0] == BB) return;
     for (unsigned i = 0; ; ++i) {
       assert(i != Blocks.size() && "Loop does not contain BB!");
@@ -217,23 +475,51 @@ public:
   /// removeBlockFromLoop - This removes the specified basic block from the
   /// current loop, updating the Blocks as appropriate.  This does not update
   /// the mapping in the LoopInfo class.
-  void removeBlockFromLoop(BasicBlock *BB);
+  void removeBlockFromLoop(BlockT *BB) {
+    RemoveFromVector(Blocks, BB);
+  }
 
   /// verifyLoop - Verify loop structure
-  void verifyLoop() const;
+  void verifyLoop() const {
+#ifndef NDEBUG
+    assert (getHeader() && "Loop header is missing");
+    assert (getLoopPreheader() && "Loop preheader is missing");
+    assert (getLoopLatch() && "Loop latch is missing");
+    for (typename std::vector<LoopBase<BlockT>*>::const_iterator I =
+         SubLoops.begin(), E = SubLoops.end(); I != E; ++I)
+      (*I)->verifyLoop();
+#endif
+  }
+
+  void print(std::ostream &OS, unsigned Depth = 0) const {
+    OS << std::string(Depth*2, ' ') << "Loop Containing: ";
+
+    for (unsigned i = 0; i < getBlocks().size(); ++i) {
+      if (i) OS << ",";
+      WriteAsOperand(OS, getBlocks()[i], false);
+    }
+    OS << "\n";
 
-  void print(std::ostream &O, unsigned Depth = 0) const;
+    for (iterator I = begin(), E = end(); I != E; ++I)
+      (*I)->print(OS, Depth+2);
+  }
+  
   void print(std::ostream *O, unsigned Depth = 0) const {
     if (O) print(*O, Depth);
   }
-  void dump() const;
+  
+  void dump() const {
+    print(cerr);
+  }
+  
 private:
   friend class LoopInfo;
-  Loop(BasicBlock *BB) : ParentLoop(0) {
+  LoopBase(BlockT *BB) : ParentLoop(0) {
     Blocks.push_back(BB);
   }
 };
 
+typedef LoopBase<BasicBlock> Loop;
 
 
 //===----------------------------------------------------------------------===//
@@ -244,7 +530,7 @@ class LoopInfo : public FunctionPass {
   // BBMap - Mapping of basic blocks to the inner most loop they occur in
   std::map<BasicBlock*, Loop*> BBMap;
   std::vector<Loop*> TopLevelLoops;
-  friend class Loop;
+  friend class LoopBase<BasicBlock>;
 public:
   static char ID; // Pass identification, replacement for typeid
 
@@ -360,6 +646,24 @@ template <> struct GraphTraits<Loop*> {
   }
 };
 
+template<class BlockT>
+void LoopBase<BlockT>::addBasicBlockToLoop(BlockT *NewBB, LoopInfo &LI) {
+  assert((Blocks.empty() || LI[getHeader()] == this) &&
+         "Incorrect LI specified for this loop!");
+  assert(NewBB && "Cannot add a null basic block to the loop!");
+  assert(LI[NewBB] == 0 && "BasicBlock already in the loop!");
+
+  // Add the loop mapping to the LoopInfo object...
+  LI.BBMap[NewBB] = this;
+
+  // Add the basic block to this loop and all parent loops...
+  LoopBase<BlockT> *L = this;
+  while (L) {
+    L->Blocks.push_back(NewBB);
+    L = L->getParentLoop();
+  }
+}
+
 } // End llvm namespace
 
 // Make sure that any clients of this file link in LoopInfo.cpp
diff --git a/include/llvm/Analysis/LoopPass.h b/include/llvm/Analysis/LoopPass.h
index 6d6d94c..b945b99 100644
--- a/include/llvm/Analysis/LoopPass.h
+++ b/include/llvm/Analysis/LoopPass.h
@@ -23,7 +23,6 @@
 namespace llvm {
 
 class LPPassManager;
-class Loop;
 class Function;
 
 class LoopPass : public Pass {
diff --git a/include/llvm/Analysis/ScalarEvolution.h b/include/llvm/Analysis/ScalarEvolution.h
index 9e9da6c..a52f273 100644
--- a/include/llvm/Analysis/ScalarEvolution.h
+++ b/include/llvm/Analysis/ScalarEvolution.h
@@ -22,6 +22,7 @@
 #define LLVM_ANALYSIS_SCALAREVOLUTION_H
 
 #include "llvm/Pass.h"
+#include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/Streams.h"
 #include <set>
@@ -32,8 +33,6 @@ namespace llvm {
   class Instruction;
   class Type;
   class ConstantRange;
-  class Loop;
-  class LoopInfo;
   class SCEVHandle;
   class ScalarEvolution;
 
diff --git a/include/llvm/Transforms/Utils/Cloning.h b/include/llvm/Transforms/Utils/Cloning.h
index 53e47a3..1d9d651 100644
--- a/include/llvm/Transforms/Utils/Cloning.h
+++ b/include/llvm/Transforms/Utils/Cloning.h
@@ -20,13 +20,12 @@
 
 #include <vector>
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/Analysis/LoopInfo.h"
 
 namespace llvm {
 
 class Module;
 class Function;
-class Loop;
-class LoopInfo;
 class Pass;
 class LPPassManager;
 class BasicBlock;
diff --git a/include/llvm/Transforms/Utils/FunctionUtils.h b/include/llvm/Transforms/Utils/FunctionUtils.h
index cf8abdf..078fab0 100644
--- a/include/llvm/Transforms/Utils/FunctionUtils.h
+++ b/include/llvm/Transforms/Utils/FunctionUtils.h
@@ -14,13 +14,13 @@
 #ifndef LLVM_TRANSFORMS_UTILS_FUNCTION_H
 #define LLVM_TRANSFORMS_UTILS_FUNCTION_H
 
-#include <llvm/Analysis/Dominators.h>
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/LoopInfo.h"
 #include <vector>
 
 namespace llvm {
   class BasicBlock;
   class Function;
-  class Loop;
 
   /// ExtractCodeRegion - rip out a sequence of basic blocks into a new function
   ///