SSA operand interface change proposal

[Zdenek Dvorak]

Hello,

> I think the changes are pretty minimal considering what we are trying to
> do.
> 
> The problem with lazy updating is PHI nodes. We dont have that facility,
> and although we could probably provide it, I doubt anyone wants to have
> to call get_stmt_operands() on phi nodes before using them.
>
> This is my 4th cut at the problem. The second cut was using the lazy
> updating as you suggest, but I ran into some implementaion issues wrt
> PHI nodes. I'd like to see all operands treated consistantly.

in the patch for the problem I posted in December
(http://gcc.gnu.org/ml/gcc/2003-12/msg00676.html) I solved this problem
simply by changing phi node arguments through replace_phi_arg_num
function consistently, which turned out to be trivial.  So I think that
the problem is not that critical, and possibly the operand
representation changes you propose could be considered as an independent
patch.

Zdenek