[Bug c/124230] bound sanitizer does not issue error for out-of-bound access through pointer array annotated with counted_by

[qinzhao at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124230

--- Comment #1 from qinzhao at gcc dot gnu.org ---
this is because the following routine doesn't handle the case when the offset
is a n integer constant: (in c-ubsan.cc)

 get_index_from_offset (tree offset, tree *index_p,
                       int *index_n, tree element_size)