Memory partitioning considered harmful (!?)

[Tobias Schlüter]

Richard Guenther wrote:
> The other thing is to use by-value argument passing conventions for
> internal intrinsics wherever possible so that a
> 
>   write (*,*) a
> 
> does not make 'a' addressable.  This is what makes fatigue so sensitive
> to the partitioning choices - we have an addressable induction variable
> and miss loop invariant motion of sin() and cos() calls if the memory
> tag for the induction variable is coalesced with the wrong things.  The
> induction variable only has a memory tag because it is marked addressable
> and this is only due to the fact that fatigue re-uses it in an I/O 
> statement (like the one quoted above) later in the function.

Is there no finer-grained control available which says "this variable's 
address is taken, but it's not written to"?  This seems useful for both 
passing structures in C code and INTENT(IN) arguments in Fortran code 
(where we can't use different calling conventions due to compatibility 
with legacy code).

- Tobi