src/v8/test/mjsunit/smi-representation.js

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// Flags: --track-fields --track-double-fields --allow-natives-syntax

function smi_field() {
  // Assign twice to make the field non-constant.
  // TODO(ishell): update test once constant field tracking is done.
  var o = {smi: 1};
  o.smi = 0;
  return o;
}

function check_smi_repr(o, d1, d2) {
  var s = o.smi;
  var d = d1 - d2;
  s = s + d;
  o.smi = s;
  return o;
}

var test = smi_field();
check_smi_repr(smi_field(), 5, 3);
check_smi_repr(smi_field(), 6, 2);
%OptimizeFunctionOnNextCall(check_smi_repr);
var val = check_smi_repr(smi_field(), 8, 1);
assertTrue(%HaveSameMap(val, test));

function tagged_smi_field() {
  var o = {"tag":false};
  o.tag = 10;
  return o;
}

function check_smi_repr_from_tagged(o, o2) {
  var t = o2.tag;
  o.smi = t;
  return o;
}

check_smi_repr_from_tagged(smi_field(), tagged_smi_field());
check_smi_repr_from_tagged(smi_field(), tagged_smi_field());
%OptimizeFunctionOnNextCall(check_smi_repr_from_tagged);
var val = check_smi_repr_from_tagged(smi_field(), tagged_smi_field());
assertTrue(%HaveSameMap(val, test));
var overflow = tagged_smi_field();
overflow.tag = 0x80000000;
var val = check_smi_repr_from_tagged(smi_field(), overflow);