trying to get a registerised alpha build

[Simon Marlow]

Duncan Coutts wrote:

> Well the full build finished and appears to work. We're going to try
> again with what I think is a better fix than just picking another fixed
> register. Instead of fixing a register we could let gcc pick any
> suitable register by use a local C variable. It'd be the same code as
> x86/amd64 use:
> 
> #define JMP_(cont)                      \
>     {                                   \
>       void *__target;                   \
>       __DISCARD__();                    \
>       __target = (void *)(cont);        \
>       goto *__target;                   \
>     }
> 
> So we'll give that a go. I don't know if the do { ... } while (0) is
> significant. I expect that with modern gcc versions that it is not.

That looks fine to me.  Just go ahead and commit, I'll merge into 6.4.2.

 > So that's the alpha registerised build mostly working. Next is the
 > mangler.

Great!

Cheers,
	Simon