maxtal@physics.su.OZ.AU (John Max Skaller) writes:

>fjh@munta.cs.mu.OZ.AU (Fergus Henderson) writes:
>>*Any* code without side effects can be optimized
>>away or inserted at will.
>
> That statement is "apparently" correct.
>(Dont you DARE optimise away my timing loops! :-))

A good optimizing compiler should at least provide an option
to optimize loops with empty bodies, IMHO.
It's certainly allowed, and it can indeed be useful.

Consider the following example:

 template <class T>
 void Array::~Array() {
  for (int i = 0; i < this->elem_count; i++) {
   this->elem[i].~T();
  }
  free(this->elem);
 }

In the case of Array<int>, the body of the loop is a call to int::~int(),
which is a no-op.  I would hope that a good optimizing compiler
would be capable of optimizing this loop away.

--
Fergus Henderson - fjh@munta.cs.mu.oz.au