[Bug c/38354] Spurious error: initializer element is not computable at load time

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38354

--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Adam Warner from comment #6)
> Just to make sure I understand this correctly:
> 
> 1. You won't confirm this bug because it violates the C standard.

You asked why it works with C++ and I told you, I didn't say anything about
confirming it or not, because I'm not a C front-end maintainer so it's not my
place to decide what is a bug in the C front-end. (IMHO it's not a bug, but
might be a valid enhancement request.)

I stand by my statement that the C standard is more restrictive about what is
allowed in a static initializer.  C++ has a "dynamic initialization" phase
which does not exist for C.

> 2. GNU provides extensions to C when the C standard is too restrictive. In
> this case the initializer element is *clearly* computable at load time
> because all function pointers are *already* 32 bits under the non-large code
> model.
> 
> 3. To demonstrate this, a GNU extension to C++ has no problem computing the
> address of the function pointer at load time and storing it in a 32-bit
> integer array.

It's not a GNU extension, it's required by the C++ standard, and it happens at
runtime, so that fails to demonstrate your point.

> 4. Just because C is supposed to be a portable assembler and lower level
> than C++ doesn't mean you should be able to store a 32-bit address in a
> 32-bit integer at load time. Even though GNU C++ can.

Except it can't.