fixed rule

GNU style is logical, because braces are syntactically a single statement:

while (x == y)
  func1();  // can be replaced by { ... }

However, I prefer to entirely avoid unbraced single statements after while/if:

while (x == y) {
  func1();  // easy to add func2(); later
}

Although this is ok when it fits:

while (x == y) func1();  // brevity!