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 bug63;
extern(C) int printf(char*, ...);

void main()
{
    static void notnested()
    {
        printf("hello world\n");
    }
    notnested();
}