[TESTCASE] Minimized testcase for AltiVec segfault

[Aldy Hernandez]

> Why can't varargs and vector arguments be supported under the SVR4
> ABI?

because things won't be aligned properly.  and if they were,
we'd no longer be SVR4 abi compliant.

>
> Isn't altivec still useful even if you can't pass vectors as
> arguments?

sure, but we don't need a flag to do that.

> The significant change that -mabi=altivec makes is that it expects
> called procedures to save the call-saved altivec registers.  Thus, you
> can't call any non-altivec-abi procedures from an altivec-abi
> procedure safely.

this however, makes a lot of sense.
>
> --
> - Geoffrey Keating <geoffk@geoffk.org> <geoffk@redhat.com>
>
>
--
Aldy Hernandez                                E-mail: aldyh@redhat.com
Professional Gypsy Lost in Australia
Red Hat, Inc.