JS code generation bug?

a.hx

//stack is an inline property performing array access
function popStack():Int
{
  var v = memory[STACK_OFFSET + stack - 1];
  stack--;
  return v;
}

a.js

//The produced code moves the decrement of stack in a way that makes the return value invalid
popStack: function() {
  this.memory[4] -= 1;
  return this.memory[384 + this.memory[4] - 1];
}

b.hx

//Introducing a trace statement to force order fixes this
function popStack():Int
{
  var v = memory[STACK_OFFSET + stack - 1];
  trace("Popping");
  stack--;
  return v;
}

b.js

popStack: function() {
  var v = this.memory[384 + this.memory[4] - 1];
  console.log("Popping");
  this.memory[4] -= 1;
  return v;
}