[Bug c/107010] iterate section("mysection") struct mystruct fails if first node is const and compiling with O2 or greater

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107010

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=77964
         Resolution|---                         |INVALID
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
That is because GCC knows that first+1 does not point to a valid pointer
really.

You need to hide the assignment of iterator from GCC.

This will fix the issue:
        const struct linkinfostruct *iterator = &first;
        asm("":"+r"(iterator));

        while (iterator->name)
        {
                fprintf (stderr, "name=%s\n", iterator->name);
                iterator++;
                fprintf (stderr, "    next iteration should be (iterator=%p,
&iterator->name=%p name=%p \"%s\"\n", iterator, &iterator->name,
iterator->name, iterator->name); 
        }


See PR 77964 and PR 106939 also.