[lno] Introduce data dependence graph

[Daniel Berlin]

On Feb 13, 2004, at 11:55 PM, Devang Patel wrote:

> This patch introduces data dependence graph based on Sebastian's scalar
> evolution analyzer. This is just a start. At this point APIs are not
> available to access dependence info from the graph. I will soon start
> adding them. I've introduced new flag -ftree-ddg to enable it. But it
> will not last forever.
>
> Bootstrapped on powerpc-apple-darwin7.2.0 with "-fscalar-evolutions 
> -ftree-ddg".
> DejaGNU test run is in progress.
>
>
Is there some good reason you aren't using an alloc pool for the fixed 
size dependence_node_def and dependence_edge structures?
It would get rid of a lot of GTY'ing, and a lot of ggc_allocing.