| What I don't understand yet is the routemap for replacing -fvia-C

Good points, Claus.  I think the story is as follows:

* -fvia-C does not produce much better code, except in exceptionally tight 
loops, because GHC gives gcc very little scope for optimisation.  Simon 
mentioned something like 1% improvement.

* -fvia-C does not give substantially improved portability, because the Evil 
Mangler must have lots of new (Perl) code for each new platform.  (And each new 
version of gcc changes the details.)

* -fvia-C does impose maintenance costs, as this thread has rehearsed.

* -fasm has the potential for producing *better* code than gcc, because we can 
temporarily re-use registers that we must nail down as far as gcc is concerned.

| In other words, what is the plan wrt to backends, especially wrt
| recovering the optimizations and portability issues previously left to
| gcc?

I think you may be over-optimistic about the portability and optimisation 
benefits. As to other back end plans, it's a fairly active place.  Ben L is 
doing great stuff on refactoring the native code back end as part of his Sparc 
NCG.  And John and Norman and I are actively (albeit diverted recently by ICFP 
submissions) working on getting the refactored STG...flat C-- story into 
mainstream.

Simon
_______________________________________________
Glasgow-haskell-users mailing list
Glasgow-haskell-users@haskell.org
http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

Reply via email to