https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91952
--- Comment #4 from Allison Karlitskaya <allison.karlitskaya at redhat dot com>
---
(In reply to Jakub Jelinek from comment #3)
> First of all, not all automatic vars live on stack, some live in registers.
Sure. The register could also be initialised to the same value, of course.
> And, what will happen say for:
> switch (n)
> {
> int x __attribute__((__default_value__((5)));
> case 10:
> foo (x);
> case 20:
> foo (x);
> break;
> }
This is pretty much exactly the case that I'm talking about and the answer is
that foo() would *always* be called with 5. The initialisation of 5 with this
attribute isn't done in the normal sense of an assignment that occurs when the
line in question is executed (note: there is no '=' anywhere in this program).
The value of 5 is written into the local variable (register or stack space) as
soon as it is allocated, regardless of if execution passes through the line
where the declaration is.
