Crankshaft part of the 'loads and stores to global vars through property cell shortcuts' feature.

test/mjsunit/regress/regress-crbug-510738.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax
+
+function check(f, result) {
+  %OptimizeFunctionOnNextCall(f);
+  assertEquals(result, f());
+}
+
+var x = 17;
+function generic_load() { return x; }
+check(generic_load, 17);
+
+function generic_store() { x = 13; return x; }
+check(generic_store, 13);