Loop optimizer issues

[Zdenek Dvorak]

Hello,

> > > > I may do the merge from mainline anyway if you insist, but imo it does
> > > > not help much.
> > > 
> > > Well I think that if it is not too much effort, it will at least allow
> > > everyone to keep all options open.  And I would expect that a merge from
> > > rtlopt to tree-ssa would be much easier to review if rtlopt was at least
> > > up-to-date with mainline.
> > 
> > actually it would be a lot of work, mostly due to hookizing the cfg.
> > Since I have not done almost any changes touching cfg, merging just the
> > changes into tree-ssa is trivial.  The other way would be painful imo.
> >
> I don't get it.  Why would it be more painful for you to merge with
> mainline than tree-ssa?  After all, outside the tree optimizers,
> tree-ssa and mainline are almost identical.

it is easy to merge loop optimizer changes into either mainline or
tree-ssa.  The other direction (merging the mainline into rtlopt)
seems more difficult to me (although not that much when I think about
it again).

Zdenek