[new-regalloc] What is the status on current sources

[Michael Matz]

Hi,

On Sat, 10 Feb 2001, Geert Bosch wrote:
> 
> I couldn't agree more that it is too early to worry about absolute
> performance, but I do think we need to be clear that the various algorithms
> can be implemented without regressing to algorithms that inherently
> require O(n**2) time.

Of course.

> An essential part of the implementation of the dataflow algorithms is
> to use DFS post-order traversal.

If iterative analysis is used, yes.

> Since it seems that flow.c is the place where we do our dataflow analysis,
> I wonder why you decided to implement a new df.c unit.

I didn't decide anything ;)  Daniel and me were in need for def/use chains
(I only reg-def reg-use lists), flow.c didn't provide that, the existing
df.c did.  You can guess the implication ;)

> It seems to me that it would be preferable to enhance the existing
> flow.c instead of writing a different piece of code that mostly does
> the same.

It does in some parts mostly the same as some parts of flow.c ;)  In
flow.c are many things: BB detection/manipulation, edge manipulation, insn
insertion, dead code removal, live register analysis, dealing with
conditional execution, converting to autoinc/dec, loop tree analysis and
more.  df.c only deals with global data flow.  And at least I am a fan of
moderately sized files ;)  df.c also has a nice interface.


Ciao,
Michael.