[Bug c/69960] "initializer element is not constant"

["daniel.lundin.mail at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69960

--- Comment #20 from Daniel Lundin <daniel.lundin.mail at gmail dot com> ---
Further info about the "ARM32 port bug". 

In case you write code like `(uint32_t)&function_pointer` and the port happens
to use 32 bit pointers, the non-conforming cast is let through. 

In case you cast to an integer type of different size in relation to the
pointer size (non-portable cast), you first get a warning about that: "warning:
cast from pointer to integer of different size [-Wpointer-to-int-cast]",
followed by the diagnostic "error: initializer element is not computable at
load time".

https://godbolt.org/z/xjYvd41qe

Correct compiler behavior here is to always give a diagnostic for
(uint32_t)&reset_handler not being an acceptable arithmetic constant
expression. 

If that's the same "implementation may accept other forms of constant
expressions"  bug as originally discussed here or a different bug, I don't
know.