[Bug tree-optimization/95663] static_cast checks for null even when the pointer is dereferenced

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95663

--- Comment #14 from Jeffrey A. Law <law at redhat dot com> ---
The reason for turning the dereference into a trap is because we can clean up
ancillary computations -- the address computation, the RHS of a store, and the
like via standard dead code elimination algorithms.