diff --git a/sdk/lib/_internal/vm/lib/array.dart b/sdk/lib/_internal/vm/lib/array.dart
index c897b67..ba48fbe 100644
--- a/sdk/lib/_internal/vm/lib/array.dart
+++ b/sdk/lib/_internal/vm/lib/array.dart
@@ -61,8 +61,11 @@
   factory _List._ofGrowableList(_GrowableList<E> elements) {
     final int length = elements.length;
     final list = _List<E>(length);
-    for (int i = 0; i < length; i++) {
-      list[i] = elements[i];
+    // TODO(30102): Remove this loop zero-trip guard.
+    if (length > 0) {
+      for (int i = 0; i < length; i++) {
+        list[i] = elements[i];
+      }
     }
     return list;
   }
@@ -70,8 +73,11 @@
   factory _List._ofList(_List<E> elements) {
     final int length = elements.length;
     final list = _List<E>(length);
-    for (int i = 0; i < length; i++) {
-      list[i] = elements[i];
+    // TODO(30102): Remove this loop zero-trip guard.
+    if (length > 0) {
+      for (int i = 0; i < length; i++) {
+        list[i] = elements[i];
+      }
     }
     return list;
   }
@@ -79,8 +85,11 @@
   factory _List._ofImmutableList(_ImmutableList<E> elements) {
     final int length = elements.length;
     final list = _List<E>(length);
-    for (int i = 0; i < length; i++) {
-      list[i] = elements[i];
+    // TODO(30102): Remove this loop zero-trip guard.
+    if (length > 0) {
+      for (int i = 0; i < length; i++) {
+        list[i] = elements[i];
+      }
     }
     return list;
   }
diff --git a/sdk/lib/_internal/vm/lib/growable_array.dart b/sdk/lib/_internal/vm/lib/growable_array.dart
index 516996f..c6d9e46 100644
--- a/sdk/lib/_internal/vm/lib/growable_array.dart
+++ b/sdk/lib/_internal/vm/lib/growable_array.dart
@@ -110,7 +110,10 @@
   // Specialization of List.empty constructor for growable == true.
   // Used by pkg/vm/lib/transformations/list_factory_specializer.dart.
   @pragma("vm:prefer-inline")
-  factory _GrowableList.empty() => _GrowableList(0);
+  factory _GrowableList.empty() {
+    // Specialization of `return _GrowableList(0);`.
+    return _GrowableList<T>._withData(_emptyList);
+  }
 
   // Specialization of List.filled constructor for growable == true.
   // Used by pkg/vm/lib/transformations/list_factory_specializer.dart.
@@ -154,43 +157,61 @@
 
   factory _GrowableList._ofList(_List<T> elements) {
     final int length = elements.length;
-    final list = _GrowableList<T>(length);
-    for (int i = 0; i < length; i++) {
-      list[i] = elements[i];
+    if (length > 0) {
+      final data = _List(_adjustedCapacity(length));
+      for (int i = 0; i < length; i++) {
+        data[i] = elements[i];
+      }
+      final list = _GrowableList<T>._withData(data);
+      list._setLength(length);
+      return list;
     }
-    return list;
+    return _GrowableList<T>.empty();
   }
 
   factory _GrowableList._ofGrowableList(_GrowableList<T> elements) {
     final int length = elements.length;
-    final list = _GrowableList<T>(length);
-    for (int i = 0; i < length; i++) {
-      list[i] = elements[i];
+    if (length > 0) {
+      final data = _List(_adjustedCapacity(length));
+      for (int i = 0; i < length; i++) {
+        data[i] = elements[i];
+      }
+      final list = _GrowableList<T>._withData(data);
+      list._setLength(length);
+      return list;
     }
-    return list;
+    return _GrowableList<T>.empty();
   }
 
   factory _GrowableList._ofImmutableList(_ImmutableList<T> elements) {
     final int length = elements.length;
-    final list = _GrowableList<T>(length);
-    for (int i = 0; i < length; i++) {
-      list[i] = elements[i];
+    if (length > 0) {
+      final data = _List(_adjustedCapacity(length));
+      for (int i = 0; i < length; i++) {
+        data[i] = elements[i];
+      }
+      final list = _GrowableList<T>._withData(data);
+      list._setLength(length);
+      return list;
     }
-    return list;
+    return _GrowableList<T>.empty();
   }
 
   factory _GrowableList._ofEfficientLengthIterable(
       EfficientLengthIterable<T> elements) {
     final int length = elements.length;
-    final list = _GrowableList<T>(length);
     if (length > 0) {
+      final data = _List(_adjustedCapacity(length));
       int i = 0;
       for (var element in elements) {
-        list[i++] = element;
+        data[i++] = element;
       }
       if (i != length) throw ConcurrentModificationError(elements);
+      final list = _GrowableList<T>._withData(data);
+      list._setLength(length);
+      return list;
     }
-    return list;
+    return _GrowableList<T>.empty();
   }
 
   factory _GrowableList._ofOther(Iterable<T> elements) {
@@ -358,11 +379,13 @@
       // Use shared empty list as backing.
       return _emptyList;
     }
-    // Round up size to the next odd number, since this is free
-    // because of alignment requirements of the GC.
-    return new _List(capacity | 1);
+    return _List(_adjustedCapacity(capacity));
   }
 
+  // Round up size to the next odd number, since this is free
+  // because of alignment requirements of the GC.
+  static int _adjustedCapacity(int capacity) => capacity | 1;
+
   // Grow from 0 to 3, and then double + 1.
   int _nextCapacity(int old_capacity) => (old_capacity * 2) | 3;
 
@@ -501,14 +524,22 @@
   }
 
   List<T> toList({bool growable: true}) {
+    // TODO(sra): We should be able to replace the following with:
+    //
+    //     return growable
+    //         ? _GrowableList<T>._ofGrowableList(this)
+    //         : _List<T>._ofGrowableList(this);
+    //
+    // However, the extra call causes a 5% regression in `ListCopy.toList.2`.
+
     final length = this.length;
     if (growable) {
       if (length > 0) {
-        final list = new _List(length);
+        final data = new _List(_adjustedCapacity(length));
         for (int i = 0; i < length; i++) {
-          list[i] = this[i];
+          data[i] = this[i];
         }
-        final result = new _GrowableList<T>._withData(list);
+        final result = new _GrowableList<T>._withData(data);
         result._setLength(length);
         return result;
       }