[Mono-devel-list] SSAPRE news

Willibald Krenn Willibald.Krenn at gmx.at
Wed Dec 1 15:22:17 EST 2004

Massimiliano Mantione schrieb:
> First, some good news: the issue my code had with loop invariants
> is gone, and with it the workaround I applied to "cover" it :-)
> This means that now SSAPRE is correctly applied to all loop
> invariants, and the resulting code performs even better!

Sounds cool :-)

> Then, a question for jit hackers...
> I finally noticed that SSAPRE and consprop|copyprop don't work
> together (and in fact this was expected, since SSAPRE doesn't like
> "messed up" SSA, and copyprop can easily produce it).

I'm by no means a jit hacker, but is the 'mess-up factor' intentional? 
Or just some un-wanted side-effect of the current algo..

> It might take me a lot to fix this thing, but in the meanwhile
> would it be OK to commit SSAPRE anyway, but leaving it disabled
> by default (even if somebody uses '-O=all')?

You know the 'cathedral and bazar' thing? ;-)

> And, by the way, when could I commit SSAPRE?

If it was me, I'd say commit it now and just disable it until you've a 
solution to the problem mentioned. (But who am I to tell..)

> One last thing: I am commenting the source, but in most cases the
> real explanation is in the SSAPRE paper. 

Do you add the paper to the docs directory? So interested developers 
(like me) have it handy..

Only, it is often not
> obvious *which* piece of the paper has the explanation (unless one
> knows the paper very well, and in that case most of the comments
> would be pointless anyway).

Well, comments are not for people who know the code...

> Would it make sense, where I do not deviate from the paper (95%
> of the code) but things are not obvious (a lot of places), to just
> put "pointers" to the paper in the comments?
> Something like "/* See section x.y.z, the paragraph about foo */".

To me that would be very helpful. Perhaps you can also add comments 
where you are not quite satisfied, or have alternative ideas that could 
be explored too? (I know, I'm asking for much, but I still have hope..)


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