[Bug sanitizer/66908] Uninitialized variable when compiled with UBsan

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66908

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
This is because of
332   *index = save_expr (*index);
333   /* Create a "(T *) 0" tree node to describe the array type.  */
that needs to be evaluated sooner I think.