c＃编译器是否将if块优化为空

Question

Is there a chance that C# will optimize the following code block?

if (specField == null || AddSystemType(specField, layout) 
                      || AddEnumType(specField, layout)
                      || AddUserType(specField, layout))
{
}

Answer 1

Well you can use ildasm to see what the compiler has optimized for yourself. But if you were expecting it to remove the code entirely, it can't - because those three method calls could throw exceptions or modify state. So the best it could do would be to emit the equivalent of:

if (specField != null)
{
    if (!AddSystemType(specField, layout))
    {
        if (!AddEnumType(specField, layout))
        {
            AddUserType(specField, layout);
        }
    }
}

Answer 2

The AddSystemType will execute and could change some states, so everything in the IF will be executed.

When using AND

if(specField == null && AddSystemType()) {

}

Then if specField is (always) null, AddSystemType() isn't executed and skipped (short circuit evaluation)