diff --git a/compiler/dex/bb_optimizations.h b/compiler/dex/bb_optimizations.h
index fba0863..764a4cf 100644
--- a/compiler/dex/bb_optimizations.h
+++ b/compiler/dex/bb_optimizations.h
@@ -178,7 +178,7 @@
 class TypeInference : public PassME {
  public:
   TypeInference()
-    : PassME("TypeInference", kRepeatingTopologicalSortTraversal, "4_post_type_cfg") {
+    : PassME("TypeInference", kRepeatingPreOrderDFSTraversal, "4_post_type_cfg") {
   }
 
   bool Worker(PassDataHolder* data) const {
diff --git a/compiler/dex/dataflow_iterator-inl.h b/compiler/dex/dataflow_iterator-inl.h
index 89f2b5c..6e25db6 100644
--- a/compiler/dex/dataflow_iterator-inl.h
+++ b/compiler/dex/dataflow_iterator-inl.h
@@ -115,6 +115,30 @@
   return res;
 }
 
+inline BasicBlock* TopologicalSortIterator::Next(bool had_change) {
+  // Update changed: if had_changed is true, we remember it for the whole iteration.
+  changed_ |= had_change;
+
+  while (loop_head_stack_->size() != 0u &&
+      (*loop_ends_)[loop_head_stack_->back().first] == idx_) {
+    loop_head_stack_->pop_back();
+  }
+
+  if (idx_ == end_idx_) {
+    return nullptr;
+  }
+
+  // Get next block and return it.
+  BasicBlockId idx = idx_;
+  idx_ += 1;
+  BasicBlock* bb = mir_graph_->GetBasicBlock((*block_id_list_)[idx]);
+  DCHECK(bb != nullptr);
+  if ((*loop_ends_)[idx] != 0u) {
+    loop_head_stack_->push_back(std::make_pair(idx, false));  // Not recalculating.
+  }
+  return bb;
+}
+
 inline BasicBlock* LoopRepeatingTopologicalSortIterator::Next(bool had_change) {
   if (idx_ != 0) {
     // Mark last processed block visited.
diff --git a/compiler/dex/dataflow_iterator.h b/compiler/dex/dataflow_iterator.h
index 188f1d9..9f17a3e 100644
--- a/compiler/dex/dataflow_iterator.h
+++ b/compiler/dex/dataflow_iterator.h
@@ -333,7 +333,9 @@
        * @param mir_graph The MIRGraph considered.
        */
       explicit TopologicalSortIterator(MIRGraph* mir_graph)
-          : DataflowIterator(mir_graph, 0, mir_graph->GetTopologicalSortOrder().size()) {
+          : DataflowIterator(mir_graph, 0, mir_graph->GetTopologicalSortOrder().size()),
+            loop_ends_(&mir_graph->GetTopologicalSortOrderLoopEnds()),
+            loop_head_stack_(mir_graph_->GetTopologicalSortOrderLoopHeadStack()) {
         // Extra setup for TopologicalSortIterator.
         idx_ = start_idx_;
         block_id_list_ = &mir_graph->GetTopologicalSortOrder();
@@ -344,44 +346,11 @@
        * @param had_change did the user of the iteration change the previous BasicBlock.
        * @return the next BasicBlock following the iteration order, 0 if finished.
        */
-      virtual BasicBlock* Next(bool had_change = false) {
-        // Update changed: if had_changed is true, we remember it for the whole iteration.
-        changed_ |= had_change;
+      virtual BasicBlock* Next(bool had_change = false) OVERRIDE;
 
-        return ForwardSingleNext();
-      }
-  };
-
-  /**
-   * @class RepeatingTopologicalSortIterator
-   * @brief Used to perform a Topological Sort Iteration of a MIRGraph.
-   * @details If there is a change during an iteration, the iteration starts over at the end of the
-   *          iteration.
-   */
-  class RepeatingTopologicalSortIterator : public DataflowIterator {
-    public:
-     /**
-      * @brief The constructor, using all of the reachable blocks of the MIRGraph.
-      * @param mir_graph The MIRGraph considered.
-      */
-     explicit RepeatingTopologicalSortIterator(MIRGraph* mir_graph)
-         : DataflowIterator(mir_graph, 0, mir_graph->GetTopologicalSortOrder().size()) {
-       // Extra setup for RepeatingTopologicalSortIterator.
-       idx_ = start_idx_;
-       block_id_list_ = &mir_graph->GetTopologicalSortOrder();
-     }
-
-     /**
-      * @brief Get the next BasicBlock depending on iteration order.
-      * @param had_change did the user of the iteration change the previous BasicBlock.
-      * @return the next BasicBlock following the iteration order, 0 if finished.
-      */
-     virtual BasicBlock* Next(bool had_change = false) {
-       // Update changed: if had_changed is true, we remember it for the whole iteration.
-       changed_ |= had_change;
-
-       return ForwardRepeatNext();
-     }
+    private:
+     const ArenaVector<BasicBlockId>* const loop_ends_;
+     ArenaVector<std::pair<uint16_t, bool>>* const loop_head_stack_;
   };
 
   /**
diff --git a/compiler/dex/frontend.cc b/compiler/dex/frontend.cc
index 07f3033..2e21d05 100644
--- a/compiler/dex/frontend.cc
+++ b/compiler/dex/frontend.cc
@@ -41,6 +41,7 @@
   // (1 << kNullCheckElimination) |
   // (1 << kClassInitCheckElimination) |
   // (1 << kGlobalValueNumbering) |
+  // (1 << kLocalValueNumbering) |
   // (1 << kPromoteRegs) |
   // (1 << kTrackLiveTemps) |
   // (1 << kSafeOptimizations) |
diff --git a/compiler/dex/frontend.h b/compiler/dex/frontend.h
index 51b6d68..bed3b97 100644
--- a/compiler/dex/frontend.h
+++ b/compiler/dex/frontend.h
@@ -41,6 +41,7 @@
   kNullCheckElimination,
   kClassInitCheckElimination,
   kGlobalValueNumbering,
+  kLocalValueNumbering,
   kPromoteRegs,
   kTrackLiveTemps,
   kSafeOptimizations,
diff --git a/compiler/dex/global_value_numbering.cc b/compiler/dex/global_value_numbering.cc
index af57529..f0f7a70 100644
--- a/compiler/dex/global_value_numbering.cc
+++ b/compiler/dex/global_value_numbering.cc
@@ -20,14 +20,16 @@
 
 namespace art {
 
-GlobalValueNumbering::GlobalValueNumbering(CompilationUnit* cu, ScopedArenaAllocator* allocator)
+GlobalValueNumbering::GlobalValueNumbering(CompilationUnit* cu, ScopedArenaAllocator* allocator,
+                                           Mode mode)
     : cu_(cu),
       mir_graph_(cu->mir_graph.get()),
       allocator_(allocator),
       bbs_processed_(0u),
       max_bbs_to_process_(kMaxBbsToProcessMultiplyFactor * mir_graph_->GetNumReachableBlocks()),
       last_value_(0u),
-      modifications_allowed_(false),
+      modifications_allowed_(true),
+      mode_(mode),
       global_value_map_(std::less<uint64_t>(), allocator->Adapter()),
       field_index_map_(FieldReferenceComparator(), allocator->Adapter()),
       field_index_reverse_map_(allocator->Adapter()),
@@ -48,19 +50,19 @@
   if (UNLIKELY(!Good())) {
     return nullptr;
   }
-  if (UNLIKELY(bb->data_flow_info == nullptr)) {
-    return nullptr;
-  }
-  if (UNLIKELY(bb->block_type == kExitBlock)) {
+  if (bb->block_type != kDalvikByteCode && bb->block_type != kEntryBlock) {
     DCHECK(bb->first_mir_insn == nullptr);
     return nullptr;
   }
-  if (UNLIKELY(bbs_processed_ == max_bbs_to_process_)) {
+  if (mode_ == kModeGvn && UNLIKELY(bbs_processed_ == max_bbs_to_process_)) {
     // If we're still trying to converge, stop now. Otherwise, proceed to apply optimizations.
-    if (!modifications_allowed_) {
-      last_value_ = kNoValue;  // Make bad.
-      return nullptr;
-    }
+    last_value_ = kNoValue;  // Make bad.
+    return nullptr;
+  }
+  if (mode_ == kModeGvnPostProcessing &&
+    mir_graph_->GetTopologicalSortOrderLoopHeadStack()->empty()) {
+    // Modifications outside loops are performed during the main phase.
+    return nullptr;
   }
   if (allocator == nullptr) {
     allocator = allocator_;
@@ -74,6 +76,7 @@
       uint16_t value_name = work_lvn_->GetSRegValueName(this_reg);
       work_lvn_->SetValueNameNullChecked(value_name);
     }
+    DCHECK(bb->first_mir_insn == nullptr);  // modifications_allowed_ is irrelevant.
   } else {
     // To avoid repeated allocation on the ArenaStack, reuse a single vector kept as a member.
     DCHECK(merge_lvns_.empty());
@@ -83,19 +86,18 @@
     // topological order, or we're recalculating a loop head and need to merge all incoming
     // LVNs. When we're not at a loop head (including having an empty loop head stack) all
     // predecessors should be preceding blocks and we shall merge all of them anyway.
-    //
-    // If we're running the modification phase of the full GVN, the loop head stack will be
-    // empty and we need to merge all incoming LVNs. If we're running just a simple LVN,
-    // the loop head stack will also be empty and there will be nothing to merge anyway.
     bool use_all_predecessors = true;
     uint16_t loop_head_idx = 0u;  // Used only if !use_all_predecessors.
-    if (mir_graph_->GetTopologicalSortOrderLoopHeadStack()->size() != 0) {
+    if (mode_ == kModeGvn && mir_graph_->GetTopologicalSortOrderLoopHeadStack()->size() != 0) {
       // Full GVN inside a loop, see if we're at the loop head for the first time.
+      modifications_allowed_ = false;
       auto top = mir_graph_->GetTopologicalSortOrderLoopHeadStack()->back();
       loop_head_idx = top.first;
       bool recalculating = top.second;
       use_all_predecessors = recalculating ||
           loop_head_idx != mir_graph_->GetTopologicalSortOrderIndexes()[bb->id];
+    } else {
+      modifications_allowed_ = true;
     }
     for (BasicBlockId pred_id : bb->predecessors) {
       DCHECK_NE(pred_id, NullBasicBlockId);
diff --git a/compiler/dex/global_value_numbering.h b/compiler/dex/global_value_numbering.h
index 27183bf..df554cd 100644
--- a/compiler/dex/global_value_numbering.h
+++ b/compiler/dex/global_value_numbering.h
@@ -28,7 +28,18 @@
 
 class GlobalValueNumbering {
  public:
-  GlobalValueNumbering(CompilationUnit* cu, ScopedArenaAllocator* allocator);
+  enum Mode {
+    kModeGvn,
+    kModeGvnPostProcessing,
+    kModeLvn
+  };
+
+  static bool Skip(CompilationUnit* cu) {
+    return (cu->disable_opt & (1u << kGlobalValueNumbering)) != 0u ||
+        cu->mir_graph->GetMaxNestedLoops() > kMaxAllowedNestedLoops;
+  }
+
+  GlobalValueNumbering(CompilationUnit* cu, ScopedArenaAllocator* allocator, Mode mode);
   ~GlobalValueNumbering();
 
   // Prepare LVN for the basic block.
@@ -44,13 +55,13 @@
   }
 
   // Allow modifications.
-  void AllowModifications() {
+  void StartPostProcessing() {
     DCHECK(Good());
-    modifications_allowed_ = true;
+    DCHECK_EQ(mode_, kModeGvn);
+    mode_ = kModeGvnPostProcessing;
   }
 
   bool CanModify() const {
-    // TODO: DCHECK(Good()), see AllowModifications() and NewValueName().
     return modifications_allowed_ && Good();
   }
 
@@ -67,8 +78,7 @@
 
   // Allocate a new value name.
   uint16_t NewValueName() {
-    // TODO: No new values should be needed once we allow modifications.
-    // DCHECK(!modifications_allowed_);
+    DCHECK_NE(mode_, kModeGvnPostProcessing);
     ++last_value_;
     return last_value_;
   }
@@ -208,6 +218,9 @@
   MIRGraph* mir_graph_;
   ScopedArenaAllocator* const allocator_;
 
+  // The maximum number of nested loops that we accept for GVN.
+  static constexpr size_t kMaxAllowedNestedLoops = 6u;
+
   // The number of BBs that we need to process grows exponentially with the number
   // of nested loops. Don't allow excessive processing for too many nested loops or
   // otherwise expensive methods.
@@ -225,6 +238,9 @@
   // LVN once for each BasicBlock.
   bool modifications_allowed_;
 
+  // Specifies the mode of operation.
+  Mode mode_;
+
   ValueMap global_value_map_;
   FieldIndexMap field_index_map_;
   ScopedArenaVector<const FieldIndexMap::value_type*> field_index_reverse_map_;
diff --git a/compiler/dex/global_value_numbering_test.cc b/compiler/dex/global_value_numbering_test.cc
index 1d9920d..82a11a5 100644
--- a/compiler/dex/global_value_numbering_test.cc
+++ b/compiler/dex/global_value_numbering_test.cc
@@ -284,8 +284,8 @@
     cu_.mir_graph->ComputeTopologicalSortOrder();
     cu_.mir_graph->SSATransformationEnd();
     ASSERT_TRUE(gvn_ == nullptr);
-    gvn_.reset(new (allocator_.get()) GlobalValueNumbering(&cu_, allocator_.get()));
-    ASSERT_FALSE(gvn_->CanModify());
+    gvn_.reset(new (allocator_.get()) GlobalValueNumbering(&cu_, allocator_.get(),
+                                                           GlobalValueNumbering::kModeGvn));
     value_names_.resize(mir_count_, 0xffffu);
     IteratorType iterator(cu_.mir_graph.get());
     bool change = false;
@@ -304,8 +304,7 @@
   void PerformGVNCodeModifications() {
     ASSERT_TRUE(gvn_ != nullptr);
     ASSERT_TRUE(gvn_->Good());
-    ASSERT_FALSE(gvn_->CanModify());
-    gvn_->AllowModifications();
+    gvn_->StartPostProcessing();
     TopologicalSortIterator iterator(cu_.mir_graph.get());
     for (BasicBlock* bb = iterator.Next(); bb != nullptr; bb = iterator.Next()) {
       LocalValueNumbering* lvn = gvn_->PrepareBasicBlock(bb);
diff --git a/compiler/dex/local_value_numbering.cc b/compiler/dex/local_value_numbering.cc
index 0fb5e48..8b7ae20 100644
--- a/compiler/dex/local_value_numbering.cc
+++ b/compiler/dex/local_value_numbering.cc
@@ -1413,8 +1413,8 @@
     case Instruction::MONITOR_EXIT:
       HandleNullCheck(mir, GetOperandValue(mir->ssa_rep->uses[0]));
       // If we're running GVN and CanModify(), uneliminated null check indicates bytecode error.
-      if ((gvn_->GetCompilationUnit()->disable_opt & (1u << kGlobalValueNumbering)) == 0u &&
-          gvn_->CanModify() && (mir->optimization_flags & MIR_IGNORE_NULL_CHECK) == 0) {
+      if ((mir->optimization_flags & MIR_IGNORE_NULL_CHECK) == 0 &&
+          gvn_->work_lvn_ != nullptr && gvn_->CanModify()) {
         LOG(WARNING) << "Bytecode error: MONITOR_EXIT is still null checked at 0x" << std::hex
             << mir->offset << " in " << PrettyMethod(gvn_->cu_->method_idx, *gvn_->cu_->dex_file);
       }
diff --git a/compiler/dex/local_value_numbering_test.cc b/compiler/dex/local_value_numbering_test.cc
index 067bea2..33d6c14 100644
--- a/compiler/dex/local_value_numbering_test.cc
+++ b/compiler/dex/local_value_numbering_test.cc
@@ -195,9 +195,9 @@
         value_names_() {
     cu_.mir_graph.reset(new MIRGraph(&cu_, &cu_.arena));
     allocator_.reset(ScopedArenaAllocator::Create(&cu_.arena_stack));
-    gvn_.reset(new (allocator_.get()) GlobalValueNumbering(&cu_, allocator_.get()));
+    gvn_.reset(new (allocator_.get()) GlobalValueNumbering(&cu_, allocator_.get(),
+                                                           GlobalValueNumbering::kModeLvn));
     lvn_.reset(new (allocator_.get()) LocalValueNumbering(gvn_.get(), 0u, allocator_.get()));
-    gvn_->AllowModifications();
   }
 
   ArenaPool pool_;
diff --git a/compiler/dex/mir_graph.cc b/compiler/dex/mir_graph.cc
index 8dded79..3fa80b9 100644
--- a/compiler/dex/mir_graph.cc
+++ b/compiler/dex/mir_graph.cc
@@ -94,6 +94,7 @@
       topological_order_loop_ends_(arena->Adapter(kArenaAllocTopologicalSortOrder)),
       topological_order_indexes_(arena->Adapter(kArenaAllocTopologicalSortOrder)),
       topological_order_loop_head_stack_(arena->Adapter(kArenaAllocTopologicalSortOrder)),
+      max_nested_loops_(0u),
       i_dom_list_(NULL),
       temp_scoped_alloc_(),
       temp_insn_data_(nullptr),
@@ -1976,6 +1977,7 @@
   // Prepare the loop head stack for iteration.
   topological_order_loop_head_stack_.clear();
   topological_order_loop_head_stack_.reserve(max_nested_loops);
+  max_nested_loops_ = max_nested_loops;
 }
 
 bool BasicBlock::IsExceptionBlock() const {
diff --git a/compiler/dex/mir_graph.h b/compiler/dex/mir_graph.h
index 80303f6..a405af1 100644
--- a/compiler/dex/mir_graph.h
+++ b/compiler/dex/mir_graph.h
@@ -708,6 +708,10 @@
     return &topological_order_loop_head_stack_;
   }
 
+  size_t GetMaxNestedLoops() const {
+    return max_nested_loops_;
+  }
+
   bool IsConst(int32_t s_reg) const {
     return is_constant_v_->IsBitSet(s_reg);
   }
@@ -1265,6 +1269,7 @@
   ArenaVector<uint16_t> topological_order_indexes_;
   // Stack of the loop head indexes and recalculation flags for RepeatingTopologicalSortIterator.
   ArenaVector<std::pair<uint16_t, bool>> topological_order_loop_head_stack_;
+  size_t max_nested_loops_;
   int* i_dom_list_;
   std::unique_ptr<ScopedArenaAllocator> temp_scoped_alloc_;
   uint16_t* temp_insn_data_;
diff --git a/compiler/dex/mir_optimization.cc b/compiler/dex/mir_optimization.cc
index 00528e5..96505ab 100644
--- a/compiler/dex/mir_optimization.cc
+++ b/compiler/dex/mir_optimization.cc
@@ -408,14 +408,14 @@
   if (bb->block_type == kDead) {
     return true;
   }
-  // Don't do a separate LVN if we did the GVN.
-  bool use_lvn = bb->use_lvn && (cu_->disable_opt & (1u << kGlobalValueNumbering)) != 0u;
+  bool use_lvn = bb->use_lvn && (cu_->disable_opt & (1u << kLocalValueNumbering)) == 0u;
   std::unique_ptr<ScopedArenaAllocator> allocator;
   std::unique_ptr<GlobalValueNumbering> global_valnum;
   std::unique_ptr<LocalValueNumbering> local_valnum;
   if (use_lvn) {
     allocator.reset(ScopedArenaAllocator::Create(&cu_->arena_stack));
-    global_valnum.reset(new (allocator.get()) GlobalValueNumbering(cu_, allocator.get()));
+    global_valnum.reset(new (allocator.get()) GlobalValueNumbering(cu_, allocator.get(),
+                                                                   GlobalValueNumbering::kModeLvn));
     local_valnum.reset(new (allocator.get()) LocalValueNumbering(global_valnum.get(), bb->id,
                                                                  allocator.get()));
   }
@@ -1297,7 +1297,7 @@
 }
 
 bool MIRGraph::ApplyGlobalValueNumberingGate() {
-  if ((cu_->disable_opt & (1u << kGlobalValueNumbering)) != 0u) {
+  if (GlobalValueNumbering::Skip(cu_)) {
     return false;
   }
 
@@ -1305,7 +1305,8 @@
   temp_scoped_alloc_.reset(ScopedArenaAllocator::Create(&cu_->arena_stack));
   DCHECK(temp_gvn_ == nullptr);
   temp_gvn_.reset(
-      new (temp_scoped_alloc_.get()) GlobalValueNumbering(cu_, temp_scoped_alloc_.get()));
+      new (temp_scoped_alloc_.get()) GlobalValueNumbering(cu_, temp_scoped_alloc_.get(),
+                                                          GlobalValueNumbering::kModeGvn));
   return true;
 }
 
@@ -1324,19 +1325,23 @@
 void MIRGraph::ApplyGlobalValueNumberingEnd() {
   // Perform modifications.
   if (temp_gvn_->Good()) {
-    temp_gvn_->AllowModifications();
-    PreOrderDfsIterator iter(this);
-    for (BasicBlock* bb = iter.Next(); bb != nullptr; bb = iter.Next()) {
-      ScopedArenaAllocator allocator(&cu_->arena_stack);  // Reclaim memory after each LVN.
-      LocalValueNumbering* lvn = temp_gvn_->PrepareBasicBlock(bb, &allocator);
-      if (lvn != nullptr) {
-        for (MIR* mir = bb->first_mir_insn; mir != nullptr; mir = mir->next) {
-          lvn->GetValueNumber(mir);
+    if (max_nested_loops_ != 0u) {
+      temp_gvn_->StartPostProcessing();
+      TopologicalSortIterator iter(this);
+      for (BasicBlock* bb = iter.Next(); bb != nullptr; bb = iter.Next()) {
+        ScopedArenaAllocator allocator(&cu_->arena_stack);  // Reclaim memory after each LVN.
+        LocalValueNumbering* lvn = temp_gvn_->PrepareBasicBlock(bb, &allocator);
+        if (lvn != nullptr) {
+          for (MIR* mir = bb->first_mir_insn; mir != nullptr; mir = mir->next) {
+            lvn->GetValueNumber(mir);
+          }
+          bool change = temp_gvn_->FinishBasicBlock(bb);
+          DCHECK(!change) << PrettyMethod(cu_->method_idx, *cu_->dex_file);
         }
-        bool change = temp_gvn_->FinishBasicBlock(bb);
-        DCHECK(!change) << PrettyMethod(cu_->method_idx, *cu_->dex_file);
       }
     }
+    // GVN was successful, running the LVN would be useless.
+    cu_->disable_opt |= (1u << kLocalValueNumbering);
   } else {
     LOG(WARNING) << "GVN failed for " << PrettyMethod(cu_->method_idx, *cu_->dex_file);
   }
diff --git a/compiler/dex/pass_driver_me.h b/compiler/dex/pass_driver_me.h
index 537ceb6..7bfaf82 100644
--- a/compiler/dex/pass_driver_me.h
+++ b/compiler/dex/pass_driver_me.h
@@ -67,9 +67,6 @@
       case kTopologicalSortTraversal:
         DoWalkBasicBlocks<TopologicalSortIterator>(&pass_me_data_holder_, me_pass);
         break;
-      case kRepeatingTopologicalSortTraversal:
-        DoWalkBasicBlocks<RepeatingTopologicalSortIterator>(&pass_me_data_holder_, me_pass);
-        break;
       case kLoopRepeatingTopologicalSortTraversal:
         DoWalkBasicBlocks<LoopRepeatingTopologicalSortIterator>(&pass_me_data_holder_, me_pass);
         break;
diff --git a/compiler/dex/pass_me.h b/compiler/dex/pass_me.h
index 8242cb8..2f3c8b2 100644
--- a/compiler/dex/pass_me.h
+++ b/compiler/dex/pass_me.h
@@ -55,7 +55,6 @@
   kRepeatingReversePostOrderDFSTraversal,  /**< @brief Depth-First-Search / Repeating Reverse Post-Order. */
   kPostOrderDOMTraversal,                  /**< @brief Dominator tree / Post-Order. */
   kTopologicalSortTraversal,               /**< @brief Topological Order traversal. */
-  kRepeatingTopologicalSortTraversal,      /**< @brief Repeating Topological Order traversal. */
   kLoopRepeatingTopologicalSortTraversal,  /**< @brief Loop-repeating Topological Order traversal. */
   kNoNodes,                                /**< @brief Skip BasicBlock traversal. */
 };