Reduce time and memory usage of GVN.

Filter out dead sregs in GVN. Reclaim memory after each LVN
in the GVN modification phase.

Bug: 16398693
Change-Id: I8c88c3009663754e1b66c0ef3f62c3b93276e385

9 files changed, 126 insertions, 70 deletions

diff --git a/compiler/dex/frontend.cc b/compiler/dex/frontend.cc
index 51446f6..11dd182 100644
--- a/compiler/dex/frontend.cc
+++ b/compiler/dex/frontend.cc
@@ -747,7 +747,7 @@ static CompiledMethod* CompileMethod(CompilerDriver& driver,
 
   /* Free Arenas from the cu.arena_stack for reuse by the cu.arena in the codegen. */
   if (cu.enable_debug & (1 << kDebugShowMemoryUsage)) {
-    if (cu.arena_stack.PeakBytesAllocated() > 256 * 1024) {
+    if (cu.arena_stack.PeakBytesAllocated() > 1 * 1024 * 1024) {
       MemStats stack_stats(cu.arena_stack.GetPeakStats());
       LOG(INFO) << method_name << " " << Dumpable<MemStats>(stack_stats);
     }
diff --git a/compiler/dex/global_value_numbering.cc b/compiler/dex/global_value_numbering.cc
index d86be4e..d7ef6f0 100644
--- a/compiler/dex/global_value_numbering.cc
+++ b/compiler/dex/global_value_numbering.cc
@@ -43,7 +43,8 @@ GlobalValueNumbering::~GlobalValueNumbering() {
   STLDeleteElements(&lvns_);
 }
 
-LocalValueNumbering* GlobalValueNumbering::PrepareBasicBlock(BasicBlock* bb) {
+LocalValueNumbering* GlobalValueNumbering::PrepareBasicBlock(BasicBlock* bb,
+                                                             ScopedArenaAllocator* allocator) {
   if (UNLIKELY(!Good())) {
     return nullptr;
   }
@@ -58,13 +59,17 @@ LocalValueNumbering* GlobalValueNumbering::PrepareBasicBlock(BasicBlock* bb) {
     last_value_ = kNoValue;  // Make bad.
     return nullptr;
   }
+  if (allocator == nullptr) {
+    allocator = allocator_;
+  }
   DCHECK(work_lvn_.get() == nullptr);
-  work_lvn_.reset(new (allocator_) LocalValueNumbering(this, bb->id));
+  work_lvn_.reset(new (allocator) LocalValueNumbering(this, bb->id, allocator));
   if (bb->block_type == kEntryBlock) {
     if ((cu_->access_flags & kAccStatic) == 0) {
       // If non-static method, mark "this" as non-null
       int this_reg = cu_->num_dalvik_registers - cu_->num_ins;
-      work_lvn_->SetSRegNullChecked(this_reg);
+      uint16_t value_name = work_lvn_->GetSRegValueName(this_reg);
+      work_lvn_->SetValueNameNullChecked(value_name);
     }
   } else {
     // To avoid repeated allocation on the ArenaStack, reuse a single vector kept as a member.
@@ -120,7 +125,9 @@ LocalValueNumbering* GlobalValueNumbering::PrepareBasicBlock(BasicBlock* bb) {
       work_lvn_->MergeOne(*merge_lvns_[0], merge_type);
       BasicBlock* pred_bb = mir_graph_->GetBasicBlock(merge_lvns_[0]->Id());
       if (HasNullCheckLastInsn(pred_bb, bb->id)) {
-        work_lvn_->SetSRegNullChecked(pred_bb->last_mir_insn->ssa_rep->uses[0]);
+        int s_reg = pred_bb->last_mir_insn->ssa_rep->uses[0];
+        uint16_t value_name = merge_lvns_[0]->GetSRegValueName(s_reg);
+        work_lvn_->SetValueNameNullChecked(value_name);
       }
     } else {
       work_lvn_->Merge(merge_type);
@@ -135,9 +142,14 @@ bool GlobalValueNumbering::FinishBasicBlock(BasicBlock* bb) {
   ++bbs_processed_;
   merge_lvns_.clear();
 
-  std::unique_ptr<const LocalValueNumbering> old_lvn(lvns_[bb->id]);
-  lvns_[bb->id] = work_lvn_.release();
-  return (old_lvn == nullptr) || !old_lvn->Equals(*lvns_[bb->id]);
+  bool change = (lvns_[bb->id] == nullptr) || !lvns_[bb->id]->Equals(*work_lvn_);
+  if (change) {
+    std::unique_ptr<const LocalValueNumbering> old_lvn(lvns_[bb->id]);
+    lvns_[bb->id] = work_lvn_.release();
+  } else {
+    work_lvn_.reset();
+  }
+  return change;
 }
 
 uint16_t GlobalValueNumbering::GetFieldId(const MirFieldInfo& field_info, uint16_t type) {
diff --git a/compiler/dex/global_value_numbering.h b/compiler/dex/global_value_numbering.h
index a12a779..c06ff6f 100644
--- a/compiler/dex/global_value_numbering.h
+++ b/compiler/dex/global_value_numbering.h
@@ -32,7 +32,8 @@ class GlobalValueNumbering {
   ~GlobalValueNumbering();
 
   // Prepare LVN for the basic block.
-  LocalValueNumbering* PrepareBasicBlock(BasicBlock* bb);
+  LocalValueNumbering* PrepareBasicBlock(BasicBlock* bb,
+                                         ScopedArenaAllocator* allocator = nullptr);
 
   // Finish processing the basic block.
   bool FinishBasicBlock(BasicBlock* bb);
@@ -55,7 +56,7 @@ class GlobalValueNumbering {
 
   // GlobalValueNumbering should be allocated on the ArenaStack (or the native stack).
   static void* operator new(size_t size, ScopedArenaAllocator* allocator) {
-    return allocator->Alloc(sizeof(GlobalValueNumbering), kArenaAllocMIR);
+    return allocator->Alloc(sizeof(GlobalValueNumbering), kArenaAllocMisc);
   }
 
   // Allow delete-expression to destroy a GlobalValueNumbering object without deallocation.
diff --git a/compiler/dex/global_value_numbering_test.cc b/compiler/dex/global_value_numbering_test.cc
index c82d231..e8501cd 100644
--- a/compiler/dex/global_value_numbering_test.cc
+++ b/compiler/dex/global_value_numbering_test.cc
@@ -212,6 +212,7 @@ class GlobalValueNumberingTest : public testing::Test {
       if (def->type == kDalvikByteCode || def->type == kEntryBlock || def->type == kExitBlock) {
         bb->data_flow_info = static_cast<BasicBlockDataFlow*>(
             cu_.arena.Alloc(sizeof(BasicBlockDataFlow), kArenaAllocDFInfo));
+        bb->data_flow_info->live_in_v = live_in_v_;
       }
     }
     cu_.mir_graph->num_blocks_ = count;
@@ -333,12 +334,23 @@ class GlobalValueNumberingTest : public testing::Test {
         ssa_reps_(),
         allocator_(),
         gvn_(),
-        value_names_() {
+        value_names_(),
+        live_in_v_(new (&cu_.arena) ArenaBitVector(&cu_.arena, kMaxSsaRegs, false, kBitMapMisc)) {
     cu_.mir_graph.reset(new MIRGraph(&cu_, &cu_.arena));
     cu_.access_flags = kAccStatic;  // Don't let "this" interfere with this test.
     allocator_.reset(ScopedArenaAllocator::Create(&cu_.arena_stack));
+    // Bind all possible sregs to live vregs for test purposes.
+    live_in_v_->SetInitialBits(kMaxSsaRegs);
+    cu_.mir_graph->ssa_base_vregs_ = new (&cu_.arena) GrowableArray<int>(&cu_.arena, kMaxSsaRegs);
+    cu_.mir_graph->ssa_subscripts_ = new (&cu_.arena) GrowableArray<int>(&cu_.arena, kMaxSsaRegs);
+    for (unsigned int i = 0; i < kMaxSsaRegs; i++) {
+      cu_.mir_graph->ssa_base_vregs_->Insert(i);
+      cu_.mir_graph->ssa_subscripts_->Insert(0);
+    }
   }
 
+  static constexpr size_t kMaxSsaRegs = 16384u;
+
   ArenaPool pool_;
   CompilationUnit cu_;
   size_t mir_count_;
@@ -347,6 +359,7 @@ class GlobalValueNumberingTest : public testing::Test {
   std::unique_ptr<ScopedArenaAllocator> allocator_;
   std::unique_ptr<GlobalValueNumbering> gvn_;
   std::vector<uint16_t> value_names_;
+  ArenaBitVector* live_in_v_;
 };
 
 class GlobalValueNumberingTestDiamond : public GlobalValueNumberingTest {
diff --git a/compiler/dex/local_value_numbering.cc b/compiler/dex/local_value_numbering.cc
index 0e072ec..5997568 100644
--- a/compiler/dex/local_value_numbering.cc
+++ b/compiler/dex/local_value_numbering.cc
@@ -197,11 +197,7 @@ LocalValueNumbering::AliasingValues* LocalValueNumbering::GetAliasingValues(
     Map* map, const typename Map::key_type& key) {
   auto lb = map->lower_bound(key);
   if (lb == map->end() || map->key_comp()(key, lb->first)) {
-    map->PutBefore(lb, key, AliasingValues(gvn_->allocator_));
-    // The new entry was inserted before lb.
-    DCHECK(lb != map->begin());
-    --lb;
-    DCHECK(!map->key_comp()(lb->first, key) && !map->key_comp()(key, lb->first));
+    lb = map->PutBefore(lb, key, AliasingValues(this));
   }
   return &lb->second;
 }
@@ -308,25 +304,37 @@ bool LocalValueNumbering::HandleAliasingValuesPut(Map* map, const typename Map::
   return true;
 }
 
-LocalValueNumbering::LocalValueNumbering(GlobalValueNumbering* gvn, uint16_t id)
+template <typename K>
+void LocalValueNumbering::CopyAliasingValuesMap(ScopedArenaSafeMap<K, AliasingValues>* dest,
+                                                const ScopedArenaSafeMap<K, AliasingValues>& src) {
+  // We need each new AliasingValues (or rather its map members) to be constructed
+  // with our allocator, rather than the allocator of the source.
+  for (const auto& entry : src) {
+    auto it = dest->PutBefore(dest->end(), entry.first, AliasingValues(this));
+    it->second = entry.second;  // Map assignments preserve current allocator.
+  }
+}
+
+LocalValueNumbering::LocalValueNumbering(GlobalValueNumbering* gvn, uint16_t id,
+                                         ScopedArenaAllocator* allocator)
     : gvn_(gvn),
       id_(id),
-      sreg_value_map_(std::less<uint16_t>(), gvn->Allocator()->Adapter()),
-      sreg_wide_value_map_(std::less<uint16_t>(), gvn->Allocator()->Adapter()),
-      sfield_value_map_(std::less<uint16_t>(), gvn->Allocator()->Adapter()),
-      non_aliasing_ifield_value_map_(std::less<uint16_t>(), gvn->Allocator()->Adapter()),
-      aliasing_ifield_value_map_(std::less<uint16_t>(), gvn->Allocator()->Adapter()),
-      non_aliasing_array_value_map_(std::less<uint16_t>(), gvn->Allocator()->Adapter()),
-      aliasing_array_value_map_(std::less<uint16_t>(), gvn->Allocator()->Adapter()),
+      sreg_value_map_(std::less<uint16_t>(), allocator->Adapter()),
+      sreg_wide_value_map_(std::less<uint16_t>(), allocator->Adapter()),
+      sfield_value_map_(std::less<uint16_t>(), allocator->Adapter()),
+      non_aliasing_ifield_value_map_(std::less<uint16_t>(), allocator->Adapter()),
+      aliasing_ifield_value_map_(std::less<uint16_t>(), allocator->Adapter()),
+      non_aliasing_array_value_map_(std::less<uint16_t>(), allocator->Adapter()),
+      aliasing_array_value_map_(std::less<uint16_t>(), allocator->Adapter()),
       global_memory_version_(0u),
-      non_aliasing_refs_(std::less<uint16_t>(), gvn->Allocator()->Adapter()),
-      escaped_refs_(std::less<uint16_t>(), gvn->Allocator()->Adapter()),
-      escaped_ifield_clobber_set_(EscapedIFieldClobberKeyComparator(), gvn->Allocator()->Adapter()),
-      escaped_array_clobber_set_(EscapedArrayClobberKeyComparator(), gvn->Allocator()->Adapter()),
-      range_checked_(RangeCheckKeyComparator() , gvn->Allocator()->Adapter()),
-      null_checked_(std::less<uint16_t>(), gvn->Allocator()->Adapter()),
-      merge_names_(gvn->Allocator()->Adapter()),
-      merge_map_(std::less<ScopedArenaVector<BasicBlockId>>(), gvn->Allocator()->Adapter()),
+      non_aliasing_refs_(std::less<uint16_t>(), allocator->Adapter()),
+      escaped_refs_(std::less<uint16_t>(), allocator->Adapter()),
+      escaped_ifield_clobber_set_(EscapedIFieldClobberKeyComparator(), allocator->Adapter()),
+      escaped_array_clobber_set_(EscapedArrayClobberKeyComparator(), allocator->Adapter()),
+      range_checked_(RangeCheckKeyComparator() , allocator->Adapter()),
+      null_checked_(std::less<uint16_t>(), allocator->Adapter()),
+      merge_names_(allocator->Adapter()),
+      merge_map_(std::less<ScopedArenaVector<BasicBlockId>>(), allocator->Adapter()),
       merge_new_memory_version_(kNoValue) {
   std::fill_n(unresolved_sfield_version_, kFieldTypeCount, 0u);
   std::fill_n(unresolved_ifield_version_, kFieldTypeCount, 0u);
@@ -352,8 +360,8 @@ bool LocalValueNumbering::Equals(const LocalValueNumbering& other) const {
 }
 
 void LocalValueNumbering::MergeOne(const LocalValueNumbering& other, MergeType merge_type) {
-  sreg_value_map_ = other.sreg_value_map_;
-  sreg_wide_value_map_ = other.sreg_wide_value_map_;
+  CopyLiveSregValues(&sreg_value_map_, other.sreg_value_map_);
+  CopyLiveSregValues(&sreg_wide_value_map_, other.sreg_wide_value_map_);
 
   if (merge_type == kReturnMerge) {
     // RETURN or PHI+RETURN. We need only sreg value maps.
@@ -361,7 +369,7 @@ void LocalValueNumbering::MergeOne(const LocalValueNumbering& other, MergeType m
   }
 
   non_aliasing_ifield_value_map_ = other.non_aliasing_ifield_value_map_;
-  non_aliasing_array_value_map_ = other.non_aliasing_array_value_map_;
+  CopyAliasingValuesMap(&non_aliasing_array_value_map_, other.non_aliasing_array_value_map_);
   non_aliasing_refs_ = other.non_aliasing_refs_;
   range_checked_ = other.range_checked_;
   null_checked_ = other.null_checked_;
@@ -380,8 +388,8 @@ void LocalValueNumbering::MergeOne(const LocalValueNumbering& other, MergeType m
   std::copy_n(other.unresolved_ifield_version_, kFieldTypeCount, unresolved_ifield_version_);
   std::copy_n(other.unresolved_sfield_version_, kFieldTypeCount, unresolved_sfield_version_);
   sfield_value_map_ = other.sfield_value_map_;
-  aliasing_ifield_value_map_ = other.aliasing_ifield_value_map_;
-  aliasing_array_value_map_ = other.aliasing_array_value_map_;
+  CopyAliasingValuesMap(&aliasing_ifield_value_map_, other.aliasing_ifield_value_map_);
+  CopyAliasingValuesMap(&aliasing_array_value_map_, other.aliasing_array_value_map_);
   escaped_refs_ = other.escaped_refs_;
   escaped_ifield_clobber_set_ = other.escaped_ifield_clobber_set_;
   escaped_array_clobber_set_ = other.escaped_array_clobber_set_;
@@ -493,8 +501,20 @@ void LocalValueNumbering::IntersectSets() {
   }
 }
 
-template <typename Map, Map LocalValueNumbering::* map_ptr>
-void LocalValueNumbering::IntersectMaps() {
+void LocalValueNumbering::CopyLiveSregValues(SregValueMap* dest, const SregValueMap& src) {
+  auto dest_end = dest->end();
+  ArenaBitVector* live_in_v = gvn_->GetMirGraph()->GetBasicBlock(id_)->data_flow_info->live_in_v;
+  DCHECK(live_in_v != nullptr);
+  for (const auto& entry : src) {
+    bool live = live_in_v->IsBitSet(gvn_->GetMirGraph()->SRegToVReg(entry.first));
+    if (live) {
+      dest->PutBefore(dest_end, entry.first, entry.second);
+    }
+  }
+}
+
+template <LocalValueNumbering::SregValueMap LocalValueNumbering::* map_ptr>
+void LocalValueNumbering::IntersectSregValueMaps() {
   DCHECK_GE(gvn_->merge_lvns_.size(), 2u);
 
   // Find the LVN with the least entries in the set.
@@ -506,18 +526,22 @@ void LocalValueNumbering::IntersectMaps() {
   }
 
   // For each key check if it's in all the LVNs.
+  ArenaBitVector* live_in_v = gvn_->GetMirGraph()->GetBasicBlock(id_)->data_flow_info->live_in_v;
+  DCHECK(live_in_v != nullptr);
   for (const auto& entry : least_entries_lvn->*map_ptr) {
-    bool checked = true;
-    for (const LocalValueNumbering* lvn : gvn_->merge_lvns_) {
-      if (lvn != least_entries_lvn) {
-        auto it = (lvn->*map_ptr).find(entry.first);
-        if (it == (lvn->*map_ptr).end() || !(it->second == entry.second)) {
-          checked = false;
-          break;
+    bool live_and_same = live_in_v->IsBitSet(gvn_->GetMirGraph()->SRegToVReg(entry.first));
+    if (live_and_same) {
+      for (const LocalValueNumbering* lvn : gvn_->merge_lvns_) {
+        if (lvn != least_entries_lvn) {
+          auto it = (lvn->*map_ptr).find(entry.first);
+          if (it == (lvn->*map_ptr).end() || !(it->second == entry.second)) {
+            live_and_same = false;
+            break;
+          }
         }
       }
     }
-    if (checked) {
+    if (live_and_same) {
       (this->*map_ptr).PutBefore((this->*map_ptr).end(), entry.first, entry.second);
     }
   }
@@ -721,11 +745,7 @@ void LocalValueNumbering::MergeAliasingValues(const typename Map::value_type& en
                                               typename Map::iterator hint) {
   const typename Map::key_type& key = entry.first;
 
-  (this->*map_ptr).PutBefore(hint, key, AliasingValues(gvn_->allocator_));
-  DCHECK(hint != (this->*map_ptr).begin());
-  AliasingIFieldValuesMap::iterator it = hint;
-  --it;
-  DCHECK_EQ(it->first, key);
+  auto it = (this->*map_ptr).PutBefore(hint, key, AliasingValues(this));
   AliasingValues* my_values = &it->second;
 
   const AliasingValues* cmp_values = nullptr;
@@ -849,8 +869,8 @@ void LocalValueNumbering::MergeAliasingValues(const typename Map::value_type& en
 void LocalValueNumbering::Merge(MergeType merge_type) {
   DCHECK_GE(gvn_->merge_lvns_.size(), 2u);
 
-  IntersectMaps<SregValueMap, &LocalValueNumbering::sreg_value_map_>();
-  IntersectMaps<SregValueMap, &LocalValueNumbering::sreg_wide_value_map_>();
+  IntersectSregValueMaps<&LocalValueNumbering::sreg_value_map_>();
+  IntersectSregValueMaps<&LocalValueNumbering::sreg_wide_value_map_>();
   if (merge_type == kReturnMerge) {
     // RETURN or PHI+RETURN. We need only sreg value maps.
     return;
@@ -1385,7 +1405,7 @@ uint16_t LocalValueNumbering::GetValueNumber(MIR* mir) {
         if (kLocalValueNumberingEnableFilledNewArrayTracking && mir->ssa_rep->num_uses != 0u) {
           AliasingValues* values = GetAliasingValues(&non_aliasing_array_value_map_, array);
           // Clear the value if we got a merged version in a loop.
-          *values = AliasingValues(gvn_->allocator_);
+          *values = AliasingValues(this);
           for (size_t i = 0u, count = mir->ssa_rep->num_uses; i != count; ++i) {
             DCHECK_EQ(High16Bits(i), 0u);
             uint16_t index = gvn_->LookupValue(Instruction::CONST, i, 0u, 0);
diff --git a/compiler/dex/local_value_numbering.h b/compiler/dex/local_value_numbering.h
index 190eab4..855d66d 100644
--- a/compiler/dex/local_value_numbering.h
+++ b/compiler/dex/local_value_numbering.h
@@ -36,7 +36,7 @@ class LocalValueNumbering {
   static constexpr uint16_t kNoValue = GlobalValueNumbering::kNoValue;
 
  public:
-  LocalValueNumbering(GlobalValueNumbering* gvn, BasicBlockId id);
+  LocalValueNumbering(GlobalValueNumbering* gvn, BasicBlockId id, ScopedArenaAllocator* allocator);
 
   BasicBlockId Id() const {
     return id_;
@@ -44,9 +44,11 @@ class LocalValueNumbering {
 
   bool Equals(const LocalValueNumbering& other) const;
 
-  // Set non-static method's "this".
-  void SetSRegNullChecked(uint16_t s_reg) {
-    uint16_t value_name = GetOperandValue(s_reg);
+  uint16_t GetSRegValueName(uint16_t s_reg) const {
+    return GetOperandValue(s_reg);
+  }
+
+  void SetValueNameNullChecked(uint16_t value_name) {
     null_checked_.insert(value_name);
   }
 
@@ -76,7 +78,7 @@ class LocalValueNumbering {
 
   // LocalValueNumbering should be allocated on the ArenaStack (or the native stack).
   static void* operator new(size_t size, ScopedArenaAllocator* allocator) {
-    return allocator->Alloc(sizeof(LocalValueNumbering), kArenaAllocMIR);
+    return allocator->Alloc(sizeof(LocalValueNumbering), kArenaAllocMisc);
   }
 
   // Allow delete-expression to destroy a LocalValueNumbering object without deallocation.
@@ -225,12 +227,12 @@ class LocalValueNumbering {
   // store or because they contained the last_stored_value before the store and thus could not
   // have changed as a result.
   struct AliasingValues {
-    explicit AliasingValues(ScopedArenaAllocator* allocator)
+    explicit AliasingValues(LocalValueNumbering* lvn)
         : memory_version_before_stores(kNoValue),
           last_stored_value(kNoValue),
-          store_loc_set(std::less<uint16_t>(), allocator->Adapter()),
+          store_loc_set(std::less<uint16_t>(), lvn->null_checked_.get_allocator()),
           last_load_memory_version(kNoValue),
-          load_value_map(std::less<uint16_t>(), allocator->Adapter()) {
+          load_value_map(std::less<uint16_t>(), lvn->null_checked_.get_allocator()) {
     }
 
     uint16_t memory_version_before_stores;  // kNoValue if start version for the field.
@@ -286,6 +288,10 @@ class LocalValueNumbering {
   bool HandleAliasingValuesPut(Map* map, const typename Map::key_type& key,
                                uint16_t location, uint16_t value);
 
+  template <typename K>
+  void CopyAliasingValuesMap(ScopedArenaSafeMap<K, AliasingValues>* dest,
+                             const ScopedArenaSafeMap<K, AliasingValues>& src);
+
   uint16_t MarkNonAliasingNonNull(MIR* mir);
   bool IsNonAliasing(uint16_t reg) const;
   bool IsNonAliasingIField(uint16_t reg, uint16_t field_id, uint16_t type) const;
@@ -314,9 +320,11 @@ class LocalValueNumbering {
   template <typename Set, Set LocalValueNumbering::* set_ptr>
   void IntersectSets();
 
+  void CopyLiveSregValues(SregValueMap* dest, const SregValueMap& src);
+
   // Intersect maps as sets. The value type must be equality-comparable.
-  template <typename Map, Map LocalValueNumbering::* map_ptr>
-  void IntersectMaps();
+  template <SregValueMap LocalValueNumbering::* map_ptr>
+  void IntersectSregValueMaps();
 
   // Intersect maps as sets. The value type must be equality-comparable.
   template <typename Map>
diff --git a/compiler/dex/local_value_numbering_test.cc b/compiler/dex/local_value_numbering_test.cc
index b3eae42..e4e944e 100644
--- a/compiler/dex/local_value_numbering_test.cc
+++ b/compiler/dex/local_value_numbering_test.cc
@@ -196,7 +196,7 @@ class LocalValueNumberingTest : public testing::Test {
     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()));
-    lvn_.reset(new (allocator_.get()) LocalValueNumbering(gvn_.get(), 0u));
+    lvn_.reset(new (allocator_.get()) LocalValueNumbering(gvn_.get(), 0u, allocator_.get()));
     gvn_->AllowModifications();
   }
 
diff --git a/compiler/dex/mir_optimization.cc b/compiler/dex/mir_optimization.cc
index d355ddc..23ceb56 100644
--- a/compiler/dex/mir_optimization.cc
+++ b/compiler/dex/mir_optimization.cc
@@ -329,7 +329,8 @@ bool MIRGraph::BasicBlockOpt(BasicBlock* bb) {
   if (use_lvn) {
     allocator.reset(ScopedArenaAllocator::Create(&cu_->arena_stack));
     global_valnum.reset(new (allocator.get()) GlobalValueNumbering(cu_, allocator.get()));
-    local_valnum.reset(new (allocator.get()) LocalValueNumbering(global_valnum.get(), bb->id));
+    local_valnum.reset(new (allocator.get()) LocalValueNumbering(global_valnum.get(), bb->id,
+                                                                 allocator.get()));
   }
   while (bb != NULL) {
     for (MIR* mir = bb->first_mir_insn; mir != NULL; mir = mir->next) {
@@ -1170,7 +1171,8 @@ void MIRGraph::ApplyGlobalValueNumberingEnd() {
     temp_gvn_->AllowModifications();
     PreOrderDfsIterator iter(this);
     for (BasicBlock* bb = iter.Next(); bb != nullptr; bb = iter.Next()) {
-      LocalValueNumbering* lvn = temp_gvn_->PrepareBasicBlock(bb);
+      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);
diff --git a/compiler/utils/scoped_arena_allocator.h b/compiler/utils/scoped_arena_allocator.h
index 37799cb..9f33f2d 100644
--- a/compiler/utils/scoped_arena_allocator.h
+++ b/compiler/utils/scoped_arena_allocator.h
@@ -222,11 +222,11 @@ class ScopedArenaAllocatorAdapter : private DebugStackReference, private DebugSt
   }
 
   void construct(pointer p, const_reference val) {
-    DebugStackIndirectTopRef::CheckTop();
+    // Don't CheckTop(), allow reusing existing capacity of a vector/deque below the top.
     new (static_cast<void*>(p)) value_type(val);
   }
   void destroy(pointer p) {
-    DebugStackIndirectTopRef::CheckTop();
+    // Don't CheckTop(), allow reusing existing capacity of a vector/deque below the top.
     p->~value_type();
   }