On Thursday, 12 October 2017 at 15:37:23 UTC, John Burton wrote:
This is an example of what I mean :-
undefined what it is meant to do anyway, so the compiler can
"optimize" out the if condition as it only affects the case
where the language doesn't define what it's supposed to do
anyway, and compiles the code as if it was :-
void test(int[] data)
{
control_nuclear_reactor();
}
Yeah the C/C++ community/haters love to talk about all the code
the compiler can inject because of undefined behavior. But that
is not what it means.
The compiler does not know the value of data.length so it could
not make such a transformation of the code. Now had the assert
been written before the if, you're telling the compiler some
properties of data.length before you check it and it could make
such optimizations.
The point is assert tells the compiler something it can use to
reason about its job, not that it can insert additional runtime
checks to see if you code is invalid an then add new jumps to
execute whatever the hell it wants.
