Any plan for rewriting loop.c using cfgloop.c

[Zdenek Dvorak]

Hello,

> >Yes, this is understood problem.  In particular expample, of strength
> >reduction, to do it strength reduction effectivly, one should know what
> >are the costs and addressing modes not available at tree-ssa level.  To
> >do it correctly one should know about overflow semantics of input
> >language not available at RTL level.
> >
> >It is however not very well understood how to best deal with it.  It is
> >probably best to experiment with both implmentations and
> >we will likely end up with loop optimizer split into multiple parts some
> >running at tree-ssa and some running at RTL level.  THat is why I do
> >believe that Zdenek's work on RTL loop optimizer is important even after
> >merging tree-ssa.
> >
> > 
> >
> Yes, I do think so. Most of the existing loop optimizations in loop.c 
> are well suited at RTL level. What I want is rewriting these RTL level 
> loop optimizations using the natural loop discovery code in cfgloop.c. 
> The current loop optimization code in loop.c using the RTL codes, e.g. 
> NOTE_INSN_LOOP_BEG and NOTE_INSN_LOOP_CONT, to find loops. It cannot 
> find loop resulted from the code other than loop statements. Sometimes 
> tt mistakes one-entry loop for multi-enty one and ignores it.
> 
> Where can I find the information and status of Zdenek's work on RTL loop 
> optimizer?

everything is in rtlopt-branch; I have no documentation except comments
in files (loop-*.c).  I have sent some summary of what is implemented
and what needs to be done/improved to the mailing list when
we were discussing a possibility of merging with tree-ssa branch, it
should be easy to find.

Zdenek