[pcvarmint]

It means that empty loops (loops with empty bodies) can be completely removed if the controlling expression has no side effects.

> This is intended to allow compiler transformations such as removal of empty loops even when termination cannot be proven.

It means while(i) {} can be eliminated as if i were 0, because there are no side effects in the loop expression or the loop body, and what would be the point of the loop if it never terminated on a non-constant expression?

As an optimization, the optimizer is allowed to eliminate it as a useless loop with no side effects. If you really want an infinite loop, you can use while (1) {}.

There are cases where automatically generated C code might have empty loops which are useless.

If you really want to go to sleep, use pause() or similar. An infinite loop eats up CPU cycles.

[TorKlingberg]

It's quite common in embedded systems to have the fault handler end with an infinite loop, to give the programmer a chance to attach a debugger an inspect the call stack. Sometimes this behavior is turned on or off with a debug flag, which can trigger this unexpected optimization if the flag is not a compile time constant.

[pcvarmint]

A halt instruction (HLT on x86) might also work.

[planteen]

You could also add a volatile declaration

[boomlinde]

You could always say

    if (flag) while (1);

[TorKlingberg]

Yes, that would make more sense. I have never seen this optimization actually bite anyone.

[rkv]

> If you really want to go to sleep, use pause() or similar. An infinite loop eats up CPU cycles

Yes but an infinite loop + sleep is okay, right?

[dfox]

From compiler's POW call to sleep() is side-effect.