node/deps/v8/test/mjsunit/const-tracking-let-no-deopt-write-if-already-not-const.js
Michaël Zasso 1d29d81c69 deps: update V8 to 12.3.219.16
PR-URL: https://github.com/nodejs/node/pull/52293
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
2024-04-19 08:39:47 +00:00

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1018 B
JavaScript

// 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 = 1;
a = 2; // Not a constant any more.
function write(newA) {
a = newA;
}
%PrepareFunctionForOptimization(write);
write(2);
%OptimizeFunctionOnNextCall(write);
write(2);
// `a` was no longer a constant when optimizing `write`, so we generate simple
// code without side data checking / invalidation.
assertOptimized(write);
write(3);
assertOptimized(write);
function read() {
return a;
}
%PrepareFunctionForOptimization(read);
%OptimizeFunctionOnNextCall(read);
assertEquals(3, read());
assertOptimized(read);
write(4);
assertOptimized(write);
assertOptimized(read);
// Calling `write` also never deopts `read` since the value was not
// embedded as a constant.