[turbofan] Introduce dedicated ObjectIsNaN operator.

test/mjsunit/number-isnan-opt.js

Index: test/mjsunit/number-isnan-opt.js
diff --git a/test/mjsunit/number-isnan-opt.js b/test/mjsunit/number-isnan-opt.js
new file mode 100644
index 0000000000000000000000000000000000000000..a5d4b9f3372c3737d4012484e6f6482f17a652f1
--- /dev/null
+++ b/test/mjsunit/number-isnan-opt.js
@@ -0,0 +1,55 @@
+// Copyright 2017 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() {
+  function foo(x) { return Number.isNaN(x); }
+
+  assertTrue(foo(+undefined));
+  assertFalse(foo(undefined));
+  %OptimizeFunctionOnNextCall(foo);
+  assertTrue(foo(+undefined));
+  assertFalse(foo(undefined));
+})();
+
+(function() {
+  function foo(x) { return Number.isNaN(+x); }
+
+  assertTrue(foo(+undefined));
+  assertFalse(foo(0));
+  %OptimizeFunctionOnNextCall(foo);
+  assertTrue(foo(+undefined));
+  assertFalse(foo(0));
+})();
+
+(function() {
+  function foo(x) { return Number.isNaN(x|0); }
+
+  assertFalse(foo(+undefined));
+  assertFalse(foo(0));
+  %OptimizeFunctionOnNextCall(foo);
+  assertFalse(foo(+undefined));
+  assertFalse(foo(0));
+})();
+
+(function() {
+  function foo(x) { return Number.isNaN("" + x); }
+
+  assertFalse(foo(undefined));
+  assertFalse(foo(0));
+  %OptimizeFunctionOnNextCall(foo);
+  assertFalse(foo(undefined));
+  assertFalse(foo(0));
+})();
+
+(function() {
+  function foo(x) { return Number.isNaN(0/0); }
+
+  assertTrue(foo());
+  assertTrue(foo());
+  %OptimizeFunctionOnNextCall(foo);
+  assertTrue(foo());
+  assertTrue(foo());
+})();