birthpoints in rtl.

[Diego Novillo]

On 3/4/08 2:12 PM, Steven Bosscher wrote:

> That code is IMHO just awfully ugly. And slow too, last I checked.

Yeah, there's quite a bit of bookkeeping needed to do incremental SSA 
updates.

> should not want that on RTL.  I don't think we should allow
> transformations on RTL that are too hard to manually update the FUD
> chains somehow.

For FUD chains, the incremental work is actually easier to code.  You 
need to re-write the FUD chains for the affected objects from scratch. 
Forcing the optimizers to maintain this themselves is certainly easier 
for the framework code, but it imposes a heavier burden on the optimizers.


Diego.