v8/test/mjsunit/deopt-recursive-lazy-once.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 --opt --no-always-opt --no-stress-fullcodegen

function foo(i, deopt = false) {
    if (i == 0) {
        if (deopt) {
            // Trigger a lazy deopt.
            %DeoptimizeNow();
        }
    } else {
        foo(i - 1, deopt);
    }
}

assertEquals(0, %GetDeoptCount(foo));

foo(10);
foo(10);
%OptimizeFunctionOnNextCall(foo);
foo(10);

assertOptimized(foo);
assertEquals(0, %GetDeoptCount(foo));

foo(10, true);

assertUnoptimized(foo);
assertEquals(1, %GetDeoptCount(foo));