C++ switch statement evaluation

Assume we have a following code:

switch (currentChar) {
    case 'G':
    case 'T':                   
    case 'M':
    case ';':                       
    case '\r':                      
    case '\n':  
        doSomething();      
        break;
}

If the first condition is met (currentChar == 'G') are the following cases also evaluated, or the program jumps straight to doSomething()?

What would be faster to execute: the switch-case, or an if with || operator?