If statements with conditions that are always false have the effect of making blocks of code non-functional. This can be useful during debugging, but should not be checked in. If statements with conditions that are always true are completely redundant, and make the code less readable.
In either case, non-conditional if statements should be removed.
if (true) {
doSomething();
}
...
if (false) {
doSomethingElse();
}
doSomething(); ...