nodejs/deps/v8/test/mjsunit/compiler/efficiency-mode-limits-tiering.js

// Copyright 2023 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 --efficiency-mode-disable-turbofan
// Flags: --efficiency-mode-for-tiering-heuristics

function f(x) {
  var y = 0;
  for (var i = 0; i < x; i++) {
    y = 1;
  }
  return y;
}

function g(iter) {
  if (%IsTurbofanEnabled()) {
    while (!%ActiveTierIsTurbofan(f) && --iter) f(10);
  }
}
%NeverOptimizeFunction(g);

if (!%IsTurbofanEnabled()) quit();

%SetPriorityBestEffort();
// There is no hard guarantee that this does enable efficiency mode...
if (%IsEfficiencyModeEnabled()) {
  g(10000);
  assertFalse(%ActiveTierIsTurbofan(f));
  %SetPriorityUserBlocking();
  if (!%IsEfficiencyModeEnabled()) {
    g(10000000);
    assertTrue(%ActiveTierIsTurbofan(f));
  }
}