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Re: [PATCH] flow.c cleanup


> Hello,
> 
> > > > It also seems to me that it duplicates existing
> > > > functionality, i.e. the EXPR_LIST and INSN_LIST chains that some
> > > > passes attach to RTL.  Could you please look into using the existing
> > > > data and/or augmenting it to serve this purpose?
> > > 
> > > there is probably some overlap with other structures used elsewhere in
> > > the compiler (surely somewhere in df.c must be something simmilar). But
> > > the structure I use is directly derived from functioning of flow.c and
> > > it would be hard to use other structure for this purpose.
> > Did you take a look at the df.c infrastructure?  It basically has
> > functions to set up the lists of sets and uses of registers/memories in
> > the insn.  What else do you need?
> 
> basically this is what I need; but the situation is complicated by
> subregs and other details I admit I do not understand well. I may try to
> teach flow.c to work with df.c datastructure if this (or some simmilar)
> patch is accepted. I cannot do it directly, as flow.c does all the stuff
> just by passing through insn structure; and while just the subset of
> patch that makes it to work on "extract" of the insn would suffice,
> slowing down things by 20% just for this is not a good idea.
> 
> > These are also not attached directly to RTL.  I've discussed that idea
> > in the past and it appears to be bad idea, as this way we can share the
> > info with trees.
> 
> I don not understand this?
Basically it would be nice if we were able to write the dataflow
analyzers independent on the IL.  They can deal with the refs and uses
and do not worry about the fact whether they are registers in RTL or variables
in tree.  Of course this is nice idea and implementation may be so
complicated that it does not worth it.  Don't know.

Honza
> 
> Zdenek


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