[turbofan] Improve inlining of Array.prototype.map

We can use the known ElementsKind to improve typing on the receiver
element load. We can allow multiple maps, as long as they have the
same ElementsKind.

Bug: v8:6896
Change-Id: Ida7df943f7d315454b58bcf4e0bbd2346406c488
Reviewed-on: https://chromium-review.googlesource.com/704921
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48367}

src/compiler/js-call-reducer.cc

@@ -834,44 +834,46 @@ Reduction JSCallReducer::ReduceArrayMap(Handle<JSFunction> function,
   if (result != NodeProperties::kReliableReceiverMaps) {
     return NoChange();
   }
-  if (receiver_maps.size() != 1) return NoChange();
-  Handle<Map> receiver_map(receiver_maps[0]);
-  ElementsKind kind = receiver_map->elements_kind();
+
+  // Ensure that any changes to the Array species constructor cause deopt.
+  if (!isolate()->IsArraySpeciesLookupChainIntact()) return NoChange();
+
+  if (receiver_maps.size() == 0) return NoChange();
+
+  const ElementsKind kind = receiver_maps[0]->elements_kind();
+
   // TODO(danno): Handle holey Smi and Object fast elements kinds and double
   // packed.
   if (!IsFastPackedElementsKind(kind) || IsDoubleElementsKind(kind)) {
     return NoChange();
   }
 
-  // We want the input to be a generic Array.
+  for (Handle<Map> receiver_map : receiver_maps) {
+    if (!CanInlineArrayIteratingBuiltin(receiver_map)) {
+      return NoChange();
+    }
+    // We can handle different maps, as long as their elements kind are the
+    // same.
+    if (receiver_map->elements_kind() != kind) {
+      return NoChange();
+    }
+  }
+
+  dependencies()->AssumePropertyCell(factory()->species_protector());
+
   Handle<JSFunction> handle_constructor(
       JSFunction::cast(
           native_context()->GetInitialJSArrayMap(kind)->GetConstructor()),
       isolate());
   Node* array_constructor = jsgraph()->HeapConstant(handle_constructor);
-  if (receiver_map->prototype() !=
-      native_context()->get(Context::INITIAL_ARRAY_PROTOTYPE_INDEX)) {
-    return NoChange();
-  }
 
-  // And ensure that any changes to the Array species constructor cause deopt.
-  if (!isolate()->IsArraySpeciesLookupChainIntact()) return NoChange();
-
-  dependencies()->AssumePropertyCell(factory()->species_protector());
 
   Node* k = jsgraph()->ZeroConstant();
-  Node* orig_map = jsgraph()->HeapConstant(receiver_map);
 
   // Make sure the map hasn't changed before we construct the output array.
-  {
-    Node* array_map = effect =
-        graph()->NewNode(simplified()->LoadField(AccessBuilder::ForMap()),
-                         receiver, effect, control);
-    Node* check_map =
-        graph()->NewNode(simplified()->ReferenceEqual(), array_map, orig_map);
-    effect =
-        graph()->NewNode(simplified()->CheckIf(), check_map, effect, control);
-  }
+  effect = graph()->NewNode(
+      simplified()->CheckMaps(CheckMapsFlag::kNone, receiver_maps), receiver,
+      effect, control);
 
   Node* original_length = graph()->NewNode(
       simplified()->LoadField(AccessBuilder::ForJSArrayLength(PACKED_ELEMENTS)),
@@ -933,19 +935,15 @@ Reduction JSCallReducer::ReduceArrayMap(Handle<JSFunction> function,
       graph()->NewNode(common()->Checkpoint(), frame_state, effect, control);
 
   // Make sure the map hasn't changed during the iteration
-  Node* array_map = effect =
-      graph()->NewNode(simplified()->LoadField(AccessBuilder::ForMap()),
-                       receiver, effect, control);
-  Node* check_map =
-      graph()->NewNode(simplified()->ReferenceEqual(), array_map, orig_map);
-  effect =
-      graph()->NewNode(simplified()->CheckIf(), check_map, effect, control);
+  effect = graph()->NewNode(
+      simplified()->CheckMaps(CheckMapsFlag::kNone, receiver_maps), receiver,
+      effect, control);
 
   // Make sure that the access is still in bounds, since the callback could have
   // changed the array's size.
   Node* length = graph()->NewNode(
-      simplified()->LoadField(AccessBuilder::ForJSArrayLength(PACKED_ELEMENTS)),
-      receiver, effect, control);
+      simplified()->LoadField(AccessBuilder::ForJSArrayLength(kind)), receiver,
+      effect, control);
   k = effect =
       graph()->NewNode(simplified()->CheckBounds(), k, length, effect, control);
 
@@ -957,7 +955,7 @@ Reduction JSCallReducer::ReduceArrayMap(Handle<JSFunction> function,
       effect, control);
 
   Node* element = graph()->NewNode(
-      simplified()->LoadElement(AccessBuilder::ForFixedArrayElement()),
+      simplified()->LoadElement(AccessBuilder::ForFixedArrayElement(kind)),
       elements, k, effect, control);
 
   Node* next_k =