[PATCH v3 3/3] PR80791 Consider doloop cmp use in ivopts

[Kewen.Lin]

Hi Segher,

on 2019/7/22 脧脗脦莽2:26, Segher Boessenkool wrote:
> Hi!
> 
> (Maybe I am missing half of the discussion -- sorry if so).
> 
> I think we should have a new iv for just the doloop (which can have the
> same starting value and step and type as another iv).
> 
> Has this been considered?
> 
> 

I don't have any patches to introduce it.  I guess you mean one pre-bind
candidate is dedicated to doloop use only?  Version 2 introduced pre-bind,
but I dropped it as it's invasive to the current selection algorithm.

The current implementation is to zeroing cost for doloop use with any 
candidates and let selection algorithm pick up whatever for it.  I think
it's fine since doloop_optimize can transform anythings to expected only
if it knows the iteration count.

Thanks,
Kewen