Loop optimiser upgrade (Was RFC: BB duplication code)

[Jan Hubicka]

> The point I was trying to make is that I do not know of a simple,
> general, way of looking at the CFG to see if the loop exit has been
> duplicated.  I cannot see how your suggestion that there may be a
> fall-through edge into the loop header will tell us this since
> I can construct an equivalent CFG using a goto.
Surely that idea won't work.  Only way I see is to duplicate in the loop
optimizer and attach the information to "loop" structure that will hopefully
be updated untill all relevant loop optimizations passes.

BTW did I sent you the bugreport about the loop discovery code, or I did forgot
about that?

Honza
> 
> Michael.
> 
>