1 files changed, 20 insertions, 15 deletions

diff --git a/compiler/dex/mir_optimization.cc b/compiler/dex/mir_optimization.cc
index 00528e5f4b..96505ab729 100644
--- a/compiler/dex/mir_optimization.cc
+++ b/compiler/dex/mir_optimization.cc
@@ -408,14 +408,14 @@ bool MIRGraph::BasicBlockOpt(BasicBlock* bb) {
   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 @@ void MIRGraph::EliminateClassInitChecksEnd() {
 }
 
 bool MIRGraph::ApplyGlobalValueNumberingGate() {
-  if ((cu_->disable_opt & (1u << kGlobalValueNumbering)) != 0u) {
+  if (GlobalValueNumbering::Skip(cu_)) {
     return false;
   }
 
@@ -1305,7 +1305,8 @@ bool MIRGraph::ApplyGlobalValueNumberingGate() {
   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 @@ bool MIRGraph::ApplyGlobalValueNumbering(BasicBlock* bb) {
 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);
   }