[turbofan] Optimize loads from the global object in JSTypeFeedbackSpecializer.

test/mjsunit/global-delete.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.

[Michael Starzinger, 2015/04/21 12:34:01]

suggestion: Should we move this file into the "compiler" supdirectory of
mjsunit? Because it seems to be targeting optimized code specifically.

[titzer, 2015/04/21 12:56:52]

Done.

+
+// Flags: --allow-natives-syntax
+
+function test(expected, f) {
+  assertEquals(expected, f());
+  assertEquals(expected, f());
+  %OptimizeFunctionOnNextCall(f);
+  assertEquals(expected, f());
+  assertEquals(expected, f());
+}
+
+function testThrows(f) {
+  assertThrows(f);
+  assertThrows(f);
+  %OptimizeFunctionOnNextCall(f);
+  assertThrows(f);
+  assertThrows(f);
+}
+
+// --- Constant case.
+a = 11;
+
+function f1() { return a; }
+test(11, f1);
+
+delete a;
+
+testThrows(f1);
+
+
+// --- SMI case.
+
+b = 11;
+b = 12;
+b = 13;
+
+function f2() { return b; }
+test(13, f2);
+
+delete b;
+
+testThrows(f2);
+
+
+// --- double case.
+
+c = 11;
+c = 12.25;
+c = 13.25;
+
+function f3() { return c; }
+test(13.25, f3);
+
+delete c;
+
+testThrows(f3);
+
+
+// --- tagged case.
+
+d = 11;
+d = 12.25;
+d = "hello";
+
+function f4() { return d; }
+test("hello", f4);
+
+delete d;
+
+testThrows(f4);