Re: Register allocation

kamalp@acm.org (Kamal R. Prasad) writes:
>"Register allocation by priority based coloring" by Chow Hennessy (ACM
>Transaction of Programming Languages and Systems, Vol 12, No 4, Oct
>1990) does use some sort of costing to find out which variable to
>assign to a register. This algorithm is an improvement over the one
>proposed by Chaitin (ref. Chaitin G.J, Register allocation and
>spilling via graph coloring In Proceedings of the ACM SIGPLAN 82,
>Symposium on Compiler Construction pp 98-105).


Not really. If you take Chow's technique, remove the live range
splitting, and add a more sophisticated technique for determining the
order of colouring, you arrive at Briggs' technique. Now, instead of
making the spilling decision during colouring, make it when
determining the order of colouring (based on worst-case assumptions),
and you arrive at Chaitin. Since Chow uses less sophisticated
ordering heuristics than Chaitin, I would not call his technique an
improvement over Chaitin's (nor the other way round).


- anton
--
M. Anton Ertl
anton@mips.complang.tuwien.ac.at
http://www.complang.tuwien.ac.at/anton/home.html

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