Now that we're using LLVM 2.5, we can stop always running the CFGSimplification pass. The pass was originally added as a workaround for a LLVM 2.4 bug where debug info would reference labels that have been optimized away.

module nested12;

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

void main()
{
    func();
}

void func()
{
    void a(int i)
    {
        printf("%d\n", i);
    }

    void b()
    {
        a(42);
    }

    b();
}