Re: GCC superblock and region formation support

[Daniel Berlin <dberlin at dberlin dot org>]

On Tue, 2005-04-19 at 10:17 -0500, Robert Kidd wrote:
> As a quick introduction, my name is Robert Kidd, and I'm working with 
> the Gelato Federation to improve the performance of GCC on Itanium.  In 
> particular, I'm looking into improving GCC's superblock support, 
> hopefully bringing over some of what we have learned with the IMPACT 
> compiler project.
> 
> After studying GCC's current tail duplication and extended basic block 
> scheduling code, I'm thinking about ways to improve GCC's 
> representation.  I'm aiming for a more concrete form than a basic block 
> trace.  Steven Bosscher pointed me in the direction of the region 
> formation project by Daniel Berlin and Kenneth Zadeck, which sounds 
> like a good basis for a superblock representation.  What is the status 
> of this project?  Has any documentation or code been released?

The algorithm used actually comes from an never-to-be published book by
Kenneth Zadeck, Fran Allen, and Barry Rosen, and AFAWK, was never
published.

As such, the algorithm used for region formation is *very heavily*
described in the code (IE the book chapter was more or less copied into
the comments, minus some texisms).


The code is functional but being actively developed, but wasn't large
enough to bother creating a new branch for it.

If you want the current code, i'm sure Kenny would be happy to send it
to you, as he sent it to Steven Bosscher.

My involvement in this is mainly explaining to Kenny how to get done
what he wants to get done in GCC :)


> 
> Thanks
> Robert Kidd
> rkidd@crhc.uiuc.edu
>