[Bug tree-optimization/26944] [4.1/4.2 Regression] -ftree-ch generates worse code

[Andrew Pinski]

> 
> 
> 
> ------- Comment #5 from dann at godzilla dot ics dot uci dot edu  2006-05-03 18:54 -------
> IMO Comment #4 does not look close enough at what is actually happening.
> IMO tree-ch is the root cause here.
> 
> Given the above CFG, critical edge splitting transforms this into:
> Given the above CFG PRE will dutifully fill with code a lot of the empty basic
> blocks: 

None of the above issues are the real issue.  TREE CH is doing the correct thing simplifying
the loop.  PRE is doing the correct thing by getting rid of redundants.  

The main issue is really the RA not being so good.

-- Pinski