[turbofan] Track multiple maps for LoadElimination.

src/compiler/js-native-context-specialization.cc

Index: src/compiler/js-native-context-specialization.cc
diff --git a/src/compiler/js-native-context-specialization.cc b/src/compiler/js-native-context-specialization.cc
index 520268bdb68491f84d981652e81fec7b4c11b764..a3c49cf486fa3f1e7166ed061806bed0e46aafe3 100644
--- a/src/compiler/js-native-context-specialization.cc
+++ b/src/compiler/js-native-context-specialization.cc
@@ -643,13 +643,13 @@ Reduction JSNativeContextSpecialization::ReduceElementAccess(
         Handle<Map> const transition_source = transition.first;
         Handle<Map> const transition_target = transition.second;
         effect = graph()->NewNode(
-            simplified()->TransitionElementsKind(
+            simplified()->TransitionElementsKind(ElementsTransition(
                 IsSimpleMapChangeTransition(transition_source->elements_kind(),
                                             transition_target->elements_kind())
                     ? ElementsTransition::kFastTransition
-                    : ElementsTransition::kSlowTransition),
-            receiver, jsgraph()->HeapConstant(transition_source),
-            jsgraph()->HeapConstant(transition_target), effect, control);
+                    : ElementsTransition::kSlowTransition,
+                transition_source, transition_target)),
+            receiver, effect, control);
       }
 
       // TODO(turbofan): The effect/control linearization will not find a
@@ -694,14 +694,13 @@ Reduction JSNativeContextSpecialization::ReduceElementAccess(
           Handle<Map> const transition_target = transition.second;
           this_effect = graph()->NewNode(
               simplified()->TransitionElementsKind(
-                  IsSimpleMapChangeTransition(
-                      transition_source->elements_kind(),
-                      transition_target->elements_kind())
-                      ? ElementsTransition::kFastTransition
-                      : ElementsTransition::kSlowTransition),
-              receiver, jsgraph()->HeapConstant(transition_source),
-              jsgraph()->HeapConstant(transition_target), this_effect,
-              this_control);
+                  ElementsTransition(IsSimpleMapChangeTransition(
+                                         transition_source->elements_kind(),
+                                         transition_target->elements_kind())
+                                         ? ElementsTransition::kFastTransition
+                                         : ElementsTransition::kSlowTransition,
+                                     transition_source, transition_target)),
+              receiver, this_effect, this_control);
         }
 
         // Load the {receiver} map.
@@ -1179,9 +1178,9 @@ JSNativeContextSpecialization::BuildPropertyAccess(
           Handle<Map> field_map;
           if (access_info.field_map().ToHandle(&field_map)) {
             // Emit a map check for the value.
-            effect = graph()->NewNode(simplified()->CheckMaps(1), value,
-                                      jsgraph()->HeapConstant(field_map),
-                                      effect, control);
+            effect = graph()->NewNode(
+                simplified()->CheckMaps(ZoneHandleSet<Map>(field_map)), value,
+                effect, control);
           }
           field_access.write_barrier_kind = kPointerWriteBarrier;
           break;
@@ -1418,9 +1417,9 @@ JSNativeContextSpecialization::BuildElementAccess(
     if (access_mode == AccessMode::kStore &&
         IsFastSmiOrObjectElementsKind(elements_kind) &&
         store_mode != STORE_NO_TRANSITION_HANDLE_COW) {
-      effect =
-          graph()->NewNode(simplified()->CheckMaps(1), elements,
-                           jsgraph()->FixedArrayMapConstant(), effect, control);
+      effect = graph()->NewNode(simplified()->CheckMaps(ZoneHandleSet<Map>(
+                                    factory()->fixed_array_map())),
+                                elements, effect, control);
     }
 
     // Check if the {receiver} is a JSArray.
@@ -1640,12 +1639,12 @@ Node* JSNativeContextSpecialization::BuildCheckHeapObject(Node* receiver,
 
 Node* JSNativeContextSpecialization::BuildCheckMaps(
     Node* receiver, Node* effect, Node* control,
-    std::vector<Handle<Map>> const& maps) {
+    std::vector<Handle<Map>> const& receiver_maps) {
   HeapObjectMatcher m(receiver);
   if (m.HasValue()) {
     Handle<Map> receiver_map(m.Value()->map(), isolate());
     if (receiver_map->is_stable()) {
-      for (Handle<Map> map : maps) {
+      for (Handle<Map> map : receiver_maps) {
         if (map.is_identical_to(receiver_map)) {
           dependencies()->AssumeMapStable(receiver_map);
           return effect;
@@ -1653,17 +1652,13 @@ Node* JSNativeContextSpecialization::BuildCheckMaps(
       }
     }
   }
-  int const map_input_count = static_cast<int>(maps.size());
-  int const input_count = 1 + map_input_count + 1 + 1;
-  Node** inputs = zone()->NewArray<Node*>(input_count);
-  inputs[0] = receiver;
-  for (int i = 0; i < map_input_count; ++i) {
-    inputs[1 + i] = jsgraph()->HeapConstant(maps[i]);
+  // TODO(turbofan): This could be more efficient.

[Jarin, 2017/01/01 19:27:35]

Remove the comment.

[Benedikt Meurer, 2017/01/02 12:32:57]

Done.

+  ZoneHandleSet<Map> maps;
+  for (Handle<Map> map : receiver_maps) {
+    maps.insert(map, graph()->zone());
   }
-  inputs[input_count - 2] = effect;
-  inputs[input_count - 1] = control;
-  return graph()->NewNode(simplified()->CheckMaps(map_input_count), input_count,
-                          inputs);
+  return graph()->NewNode(simplified()->CheckMaps(maps), receiver, effect,
+                          control);
 }
 
 void JSNativeContextSpecialization::AssumePrototypesStable(