Index: include/llvm/Analysis/LoopInfo.h
===================================================================
--- include/llvm/Analysis/LoopInfo.h
+++ include/llvm/Analysis/LoopInfo.h
@@ -570,6 +570,23 @@
   reverse_iterator rend() const { return TopLevelLoops.rend(); }
   bool empty() const { return TopLevelLoops.empty(); }
 
+  /// Return all of the loops in the function in preorder across the loop
+  /// nests, with siblings in forward program order.
+  ///
+  /// Note that because loops form a forest of trees, preorder is equivalent to
+  /// reverse postorder.
+  SmallVector<LoopT *, 4> getLoopsInPreorder();
+
+  /// Return all of the loops in the function in preorder across the loop
+  /// nests, with siblings in *reverse* program order.
+  ///
+  /// Note that because loops form a forest of trees, preorder is equivalent to
+  /// reverse postorder.
+  ///
+  /// Also note that this is *not* a reverse preorder. Only the siblings are in
+  /// reverse program order.
+  SmallVector<LoopT *, 4> getLoopsInReverseSiblingPreorder();
+
   /// Return the inner most loop that BB lives in. If a basic block is in no
   /// loop (for example the entry node), null is returned.
   LoopT *getLoopFor(const BlockT *BB) const { return BBMap.lookup(BB); }
Index: include/llvm/Analysis/LoopInfoImpl.h
===================================================================
--- include/llvm/Analysis/LoopInfoImpl.h
+++ include/llvm/Analysis/LoopInfoImpl.h
@@ -507,6 +507,54 @@
   DFS.traverse(DomRoot->getBlock());
 }
 
+template <class BlockT, class LoopT>
+void LoopInfoBase<BlockT, LoopT>::getLoopsInPreorder() {
+  SmallVector<LoopT *, 4> PreOrderLoops, PreOrderWorklist;
+  // The outer-most loop actually goes into the result in the same relative
+  // order as we walk it. But LoopInfo stores the top level loops in reverse
+  // program order so for here we reverse it to get forward program order.
+  // FIXME: If we change the order of LoopInfo we will want to remove the
+  // reverse here.
+  for (LoopT *RootL : reverse(*this)) {
+    assert(PreOrderWorklist.empty() &&
+           "Must start with an empty preorder walk worklist.");
+    PreOrderWorklist.push_back(RootL);
+    do {
+      LoopT *L = PreOrderWorklist.pop_back_val();
+      // Sub-loops are stored in forward program order, but will process the
+      // worklist backwards so append them in reverse order.
+      PreOrderWorklist.append(L->rbegin(), L->rend());
+      PreOrderLoops.push_back(L);
+    } while (!PreOrderWorklist.empty());
+  }
+
+  return PreOrderLoops;
+}
+
+template <class BlockT, class LoopT>
+void LoopInfoBase<BlockT, LoopT>::getLoopsInReverseSiblingPreorder() {
+  SmallVector<LoopT *, 4> PreOrderLoops, PreOrderWorklist;
+  // The outer-most loop actually goes into the result in the same relative
+  // order as we walk it. LoopInfo stores the top level loops in reverse
+  // program order so we walk in order here.
+  // FIXME: If we change the order of LoopInfo we will want to add a reverse
+  // here.
+  for (LoopT *RootL : *this) {
+    assert(PreOrderWorklist.empty() &&
+           "Must start with an empty preorder walk worklist.");
+    PreOrderWorklist.push_back(RootL);
+    do {
+      LoopT *L = PreOrderWorklist.pop_back_val();
+      // Sub-loops are stored in forward program order, but will process the
+      // worklist backwards so we can just append them in order.
+      PreOrderWorklist.append(L->begin(), L->end());
+      PreOrderLoops.push_back(L);
+    } while (!PreOrderWorklist.empty());
+  }
+
+  return PreOrderLoops;
+}
+
 // Debugging
 template<class BlockT, class LoopT>
 void LoopInfoBase<BlockT, LoopT>::print(raw_ostream &OS) const {
Index: lib/Analysis/LoopAnalysisManager.cpp
===================================================================
--- lib/Analysis/LoopAnalysisManager.cpp
+++ lib/Analysis/LoopAnalysisManager.cpp
@@ -31,24 +31,10 @@
     FunctionAnalysisManager::Invalidator &Inv) {
   // First compute the sequence of IR units covered by this proxy. We will want
   // to visit this in postorder, but because this is a tree structure we can do
-  // this by building a preorder sequence and walking it in reverse.
-  SmallVector<Loop *, 4> PreOrderLoops, PreOrderWorklist;
-  // Note that we want to walk the roots in reverse order because we will end
-  // up reversing the preorder sequence. However, it happens that the loop nest
-  // roots are in reverse order within the LoopInfo object. So we just walk
-  // forward here.
-  // FIXME: If we change the order of LoopInfo we will want to add a reverse
-  // here.
-  for (Loop *RootL : *LI) {
-    assert(PreOrderWorklist.empty() &&
-           "Must start with an empty preorder walk worklist.");
-    PreOrderWorklist.push_back(RootL);
-    do {
-      Loop *L = PreOrderWorklist.pop_back_val();
-      PreOrderWorklist.append(L->begin(), L->end());
-      PreOrderLoops.push_back(L);
-    } while (!PreOrderWorklist.empty());
-  }
+  // this by building a preorder sequence and walking it backwards. We also
+  // want siblings in forward program order to match the LoopPassManager so we
+  // get the preorder with siblings reversed.
+  SmallVector<Loop *, 4> PreOrderLoops = LI->getLoopsInReverseSiblingPreorder();
 
   // If this proxy or the loop info is going to be invalidated, we also need
   // to clear all the keys coming from that analysis. We also completely blow