[turbofan] Teach escape analysis about ObjectIsNaN.

BUG=chromium:698607
R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2735633003
Cr-Commit-Position: refs/heads/master@{#43612}

src/compiler/escape-analysis.cc

@@ -840,6 +840,7 @@ bool EscapeStatusAnalysis::CheckUsesForEscape(Node* uses, Node* rep,
       case IrOpcode::kStringCharCodeAt:
       case IrOpcode::kStringIndexOf:
       case IrOpcode::kObjectIsDetectableCallable:
+      case IrOpcode::kObjectIsNaN:
       case IrOpcode::kObjectIsNonCallable:
       case IrOpcode::kObjectIsNumber:
       case IrOpcode::kObjectIsReceiver:

test/mjsunit/regress/regress-crbug-698607.js

+// 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 assertSame(expected, found) {
+  if (found === expected) {
+  } else if ((expected !== expected) && (found !== found)) {
+  }
+}
+
+function foo() {
+  var x = {var: 0.5};
+  assertSame(x, x.val);
+  return () => x;
+}
+
+foo(1);
+foo(1);
+%OptimizeFunctionOnNextCall(foo);
+foo(1);