[tuples] gimple_assign_subcode for GIMPLE_SINGLE_RHS

[Richard Guenther]

On Sun, Mar 9, 2008 at 2:17 PM, Diego Novillo <dnovillo@google.com> wrote:
> On Sun, Mar 9, 2008 at 08:15, Richard Guenther
>  <richard.guenther@gmail.com> wrote:
>
>  >  What is GIMPLE_SINGLE_RHS after all?
>
>  Represents a "copy" operation, an operand with no operator (e.g., a = 3, b = c)
>
>  '3' and 'c' are "single" operands.  There is no operator involved in
>  the assignment.

So as opposed to a unary operation which would look exactly the same apart
from having a subcode?  So what does gimple_assign_subcode () return
for the GIMPLE_SINGLE_RHS case?  Some random garbage?

Seems I need to look at the tuples branch closer.  Is there some overview
documentation available that explains all the above?

Thanks,
Richard.