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Re: [patch] Lno branch merge part 1 -- df.c improvements


> > Part 3) originally comes from rtlopt-branch, where it helped more
> significantly
> > on some testcases (that I unfortunately cannot find anymore).
> >
> > Part two enables us to focus just on the parts of the cfg we are
> > interested in (the loops), which definitely seems good for performance.
> > This part might also be interesting in other parts of compiler (the
> > modulo scheduling, according to what was said in the talk on gcc summit,
> > might use it as well).
> Yes that is correct. However currently SMS calls df-analysis only once for
> the whole function, build DDGs for all the single-basic-block loops saves
> them
> and then perform SMS on each one of them. Using the new improvements may
> reduce memory usage. It this a trade-off between better memory usage and
> having more accurate DF information?

I think the information should be still as accurate as before; I believe
you are not interested in parts of the UD chains (or whatever you use in SMS)
outside of the loops.


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