v8/test/mjsunit/regress/regress-9441.js

// Copyright 2020 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 --turbofan --no-always-turbofan

// This test does not work well if we flush the feedback vector, which causes
// deoptimization.
// Flags: --no-stress-flush-code --no-flush-bytecode

function foo(a, b) {
    return a - b;
}

%PrepareFunctionForOptimization(foo);
assertEquals(-1n, foo(1n, 2n));
%OptimizeFunctionOnNextCall(foo);
assertEquals(1n, foo(2n, 1n));
assertOptimized(foo);
assertThrows(() => foo(2n, undefined));
if (%Is64Bit()) {
    assertUnoptimized(foo);
}
%PrepareFunctionForOptimization(foo);
%OptimizeFunctionOnNextCall(foo);
assertEquals(-1n, foo(1n, 2n));
assertOptimized(foo);
assertThrows(() => foo(undefined, 2n));
assertOptimized(foo);