Loop optimizer issues

[Zdenek Dvorak]

Hello,

> > 	I'm sorry, I'm still confused.  If you are writing an RTL-based
> > loop optimizer, you cannot avoid supporting LIBCALLs.  As long as you are
> > working in the RTL space, you cannot make the simplification that Tree-SSA
> > would allow.
> 
> Indeed.  At least for 3.4, when the tree-ssa optimizations aren't done.

there is no way how I could manage to finish the loop optimizer work
for 3.4, so I don't care.

> It's not clear what loop optimizations should be done at the rtl level
> when tree-ssa is present.

but surely the code motion I'm concerned with will at least partially be
done on tree-ssa (as loop invariant motion or pre or perhaps both).

Zdenek