nodejs/deps/v8/test/mjsunit/const-tracking-let-already-not-constant-no-deopt-maglev.js

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// Copyright 2024 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: --const-tracking-let --allow-natives-syntax
// Flags: --turbofan --no-always-turbofan --maglev --no-stress-maglev
// Flags: --sparkplug --no-always-sparkplug
let a = 0;
function read() {
return a;
}
%PrepareFunctionForOptimization(read);
assertEquals(0, read());
%OptimizeFunctionOnNextCall(read);
assertEquals(0, read());
assertOptimized(read);
function write(newValue) {
a = newValue;
}
%PrepareFunctionForOptimization(write);
write(0);
%OptimizeMaglevOnNextCall(write);
write(0);
// Invalidate the constness from the outside (of `write`).
a = 3;
assertUnoptimized(read);
assertEquals(3, read());
// Write was also deoptimized, because it depends on `a` constness.
assertUnoptimized(write);
%OptimizeMaglevOnNextCall(write);
write(1);
// Now it depends on Sminess of the context slot.
assertOptimized(write);
assertEquals(1, read());