[tree-ssa] RFC: Making control flow more explicit

[Andrew MacLeod]

On Mon, 2003-08-11 at 15:51, Zdenek Dvorak wrote:
> Hello,
> 
> [snip]
> 
> > So why are you remoiving the concept of a parent?  Or is there simply a
> > different way of getting to it?
> 
> because parent obviously is not what you want here. IIRC in the ssa dce
> algorithm marking of the neccesary control statements is somehow
> done using dominator information.
> 

The algorithm says to mark the stmts which are "control dependant". 

I dont think dominator information is sufficient. I can easily think of
cases where the conditional doesn't dominate the block

ie 
goto label;
...

if (x)
  label:
  stmt;

So the conditional doesnt dominate. You might be able to sort it out by
following predecessors and looking at the last stmt in the pred block...
as long as we dont do a lot of duplicate work while doing it.

Let me look at it for a bit, We might be able to sort it out in a
reasonably efficient way.

Andrew