Godbolt example

Unoptimized build will generate dead code for code like return rand(); even if it will never be executed. The dead code can be avoided by enclosing in else scope (see fooB in the godbolt example).

template<int i>
int fooA(){
    if constexpr(i<10){
        return 0;
    }
    return rand();
}

There are some patterns like this in the current library. For example, the following lines can be enclosed in else scope.

And due to this, I guess is_constant_evaluated() is causing a lot of unavoidable dead code in debug build. See fooC in the godbolt example.