Add some alignment info where LLVM might otherwise be more pessimistic. In particular, %.nest_arg is always aligned even though it's bitcast from i8*. Pointers in vtables are also guaranteed to be stored at aligned addresses.

module foreach4;
extern(C) int printf(char*, ...);
void main()
{
    int[] arr = new int[4];
    foreach(i,v;arr) {
        printf("arr[%u] = %d\n",i,v);
    }
}