[Bug rtl-optimization/37516] ~(-2 - a) is not being optimized into a + 1

["pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37516

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-02-23 22:15:05 UTC ---

> Maybe get away with these old-stylish names ('tree' and 'fold') and
> make it match reality, gimple-ssa-combine.c ;)

That sounds like a good idea.  I have done that.

> 
> Still have to have a look at your branch - do you have a brief
> overview documentation, for example on the wiki?  What I'd like
> to do is have an interface that I can re-use for VN combining,
> basically replace its simplify_*_expression functions.

I don't have one yet.  But I hope to create one this weekend.

Right now replacing the VN combining with this new functionality will not work
as it scans the defs itself.  Though I am moving all the def scanning to its
own function which should allow for the code to be more modular and allow for
the VN combining to work with it.