Implement first D-specific optimization pass: -simplify-drtcalls. It uses the machinery of the standard -simplify-libcalls pass, but optimizes calls to the D runtime instead of calls to C libraries. At the moment, these optimizations are implemented by this pass: - Avoid the runtime call for `arr.length = newlen` if it can determine that the new length isn't longer than the old one. - Ditto for `cast(T[]) arr` if it will clearly always succeed. (e.g. if the length of the original array is zero, or if the old element size is a multiple of the new element size)

extern(C) int printf(char*, ...);

class C
{
    int i;
    void p()
    {
        printf("%d\n", i);
    }
}

void main()
{
    printf("should print 4\n");
    C c = new C;
    c.i = 4;
    c.p();
    //delete c;
}