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Re: RFH: _inter_-procedure optimizations "CALL_REALLY_USED_REGISTERS"
On Sunday 07 August 2005 14:07, BjÃrn Haase wrote:
> I think that such kind of optimization could help very much for my
> fractional numerics library where some functions tend to be lengthy but use
> very few registers. I would be willing to try to implement it.
>
> I can imagine two possible approaches for addressing the issue. One that
> only needs adaptions in the back-end and implements the optimization only
> for one target and then one more generic solution.
>
>
> 1.) target specific approach
I wouldn't do that...
> 2.) generic
>
> One could of course try to store the information on register usage
> somewhere in the tree structure.
...but I wouldn't do this either.
You could add a HARD_REG_SET to cgraph_rtl_info and teach caller-save.c
about it. I'm sure there are lots of other places that would require
changes, but I have no idea how much, or if it is at all feasible. In
any case, you should assume that it is a much bigger job than just
modifying the call expander.
Gr.
Steven