v8/test/mjsunit/compiler/load-elimination-params.js

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// Flags: --allow-natives-syntax --load-elimination

// Test local load elimination of redundant loads and stores.

function B(x, y) {
  this.x = x;
  this.y = y;
  return this;
}

function test_params1(a, b) {
  var i = a.x;
  var j = a.x;
  var k = b.x;
  var l = b.x;
  return i + j + k + l;
}

%PrepareFunctionForOptimization(test_params1);

assertEquals(14, test_params1(new B(3, 4), new B(4, 5)));
assertEquals(110, test_params1(new B(11, 7), new B(44, 8)));

%OptimizeFunctionOnNextCall(test_params1);

assertEquals(6, test_params1(new B(1, 7), new B(2, 8)));

function test_params2(a, b) {
  var o = new B(a + 1, b);
  o.x = a;
  var i = o.x;
  o.x = a;
  var j = o.x;
  o.x = b;
  var k = o.x;
  o.x = b;
  var l = o.x;
  return i + j + k + l;
}

%PrepareFunctionForOptimization(test_params2);

assertEquals(14, test_params2(3, 4));
assertEquals(110, test_params2(11, 44));

%OptimizeFunctionOnNextCall(test_params2);

assertEquals(6, test_params2(1, 2));