v8/test/mjsunit/regress/regress-698790.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

// Call RegExp constructor with a cons string.

var cons_string = %ConstructConsString("", "aaaaaaaaaaaaaa");
new RegExp(cons_string);

// Same thing but using TF lowering.

function make_cons_string(s) {
  return s + 'aaaaaaaaaaaaaa';
};
%PrepareFunctionForOptimization(make_cons_string);
make_cons_string('');
%OptimizeFunctionOnNextCall(make_cons_string);
var cons_str = make_cons_string("");
new RegExp(cons_str);