alpha haifa regression

[Joern Rennecke]

>   > I propose to cast to a (struct { TYPE t;} *) instead, and dereference that
>   > and select the t member (can of course both be done with the -> operator).
> I think this is more complicated than we need.
> 
> Emitting the blockage is easy and is unlikely to have any noticable impact
> on performance.

But for ports where the arguments are set up with __builtin_saveregs -
expanded from va_start - this would require two blockage insns - one
in front and one at the end - which could end up in an advanced position
in the function too.