New Regalloc development stalled?

[Nathanael Nerode]

Michael Matz said
 >On 21 Nov 2002, Gabriel Dos Reis wrote:
 >
 >> | Known problem.  Some sources have even higher additional costs. 
 >This will
 >> | be fixed hopefully before 3.4.
 >>
 >> Is there any actual plan for that? I know there is a branch, but I
 >> didn't see any actual plan.
 >
 >Unfortunately it's just in my head.  The current representation of the
 >conflict graph is highly suboptimal for splitting coalesced nodes. 
Due >to
 >that there are some hot fixes in it (to keep it correct), which >basically
 >needs something like O(n^3) (worst case) per splitted node.  Those
This is not good. :-)

 >won't
 >be needed in the final version.  But even without that the underlying
 >representation is not very well fit for that kind of things, so I plan >to
 >rewrite it into something using the usual conflict bitmaps, but helped >by
 >some hash table for "difficult" edges (those which would need a >reference
 >count).  Another problem is the scattering of information over >different
 >data structures, which sometimes needs translation from one to the >other
 >data set.  That also needs cleanup.
Have you made any progress on this data structure rewrite?  It seems 
that new-ra isn't really a practical replacement for the existing one 
until these issues are solved.

 >That having said some other people already asked for something like a >web
 >page listing things we tried already, and things planned and such, for 
 >the
 >allocator.  I promised to write something over the next days ;-)
But you didn't, did you. ;-)

How about doing that now?  At any rate it will give other people a 
better chance of working on new-ra.

--Nathanael

Ciao,
Michael.