Another correction: Shin-ming Liu (HP) attended the meeting. In fact, he led the call :-)
> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf > Of Mark K. Smith > Sent: Monday, September 19, 2005 4:00 PM > To: Gelato-GCC; GCC > Subject: 15 Sept notes from GCC improvement for Itanium conference > call > > ON THE CALL: Bob Kidd (UIUC), Vladimir Makarov (Red Hat), Mark Smith > (Gelato), Wenguang Chen (Tsinghua), Mark Davis (Intel), Diego > Novillo > (Red Hat), Andrey Belevantsev (RAS), Dan Berlin (dberlin.org), Wen- > mei > Hwu (UIUC) > > The call covered: > - current status / updates on the 3 improvement areas > - brain storming how to help out Dan with the alias analysis > improvement TODO list > - GCC session at Brazil Gelato meeting > - planned presentations (tentative schedule): > - Diego Novillo (Monday 10/3, 7:30 to 8pm) > - Shin-ming Liu (Monday 10/3, 8 to 8:30pm) > - Bob Kidd (Monday 10/3, 8:30 to 9pm > - Canqun Yang (Tuesday 10/4, 10 to 10:30am) > - general discussion (Tuesday 10/4, 10:30 to 11:30am) > - next steps, action items > - continue discussion on alias analysis improvements > and determine concrete ways to help > - review and update IA-64 project list > - a discussion on corporate IP needed for GCC -- > can companies donate IP to GCC? > - planned attendance (from those on the call) > - Bob Kidd > - Shin-ming Liu > - Mark Davis > - Wenguang Chen > - Diego Novillo > - Mark Smith > > Additional detail can be found below. > > NEXT MEETING: At Gelato Meeting in Porto Alegre, Brazil, October 2-5, > 2005. > > Bob Kidd: > --------- > The patch to move superblock formation is ready to go and tested on > x86, x86_64, and ia64. I'll post it to gcc-patches and post a > message to the gcc mailing list with details shortly. > > Dan Berlin: > ----------- > The current status of the aliasing work is that work is proceeding > on > both intraprocedural and interprocedural call clobbering. Most of > the > infrasturcture to get it to be able to be start work on the actual > improved algorithms and use the results is done, or will be done by > next week. > > The main task that it would be helpful to have other people work on > would be the "Aliasing Oracle" (pairwise query system for > statements) > implementation for tree-ssa. The backend already uses a query > system > exclusively (because it's aliasing is almost exclusively type based). > This is an alternate way of representing and accessing the aliasing > results that can provide better information (though more expensive > to > query) than the current representation provides. Our current > analyses > can actually provide better information that we represent. The > eventual plan is to have a hybrid where optimizations use the > current > "virtual ssa" form to discover what appear to be things that alias, > then query the "Aliasing Oracle" to see if it can disambiguate the > aliases further if necessary (IE it decides it wants to try to sink > a > store past that point, or whatever). > > The implementation can start out simple, (IE even something that > simply looked at base + offset of pointers in the two statements, > and > gave answers, would be a good start) and I'm more than happy to > help > mentor/introduce anyone to how to work with GCC's tree-ssa form to > make this work, if they want to help implement it. Seriously. I'm > really more than happy to spend hours teaching someone how to work > with this stuff. IBM Research is also more than happy to let me do > so. I already help Ken Zadeck a lot with understanding how to get > things done in GCC, and he has become quite adept at working with > GCC > in a short time (< 6 months). If somebody has the resources to > provide someone competent to work on aliasing, I'm glad to put them > to > work for you being productive on GCC :). > > Vladimir Makarov: > ----------------- > Zdenek Dvorak submitted a patch implementing prefetching on tree-ssa > recently. It would be interesting to look how it will work for > Itanium. > > HP and Intel are interesting in gcc performance improvement. If HP > and Intel guys know for sure that gcc uses their patents or some > their > patents could be used for gcc performance improvement, it would be > good to give FSF a permission to use the patents in gcc. On the > other > hand, investigating what patents gcc uses might be a dangerous thing > because any compiler most probably uses algorithms patented by other > companies. > > Diego Novillo: > -------------- > I spoke briefly about GCC's development process: > > * Legal issues need to be resolved early. Assign personal and > corporate copyright to the FSF. > * It's important to participate in the main development lists (gcc > and gcc-patches). IRC is a good meeting place, too. > * GCC works in three main stages: > o Stage 1: Everything goes. > o Stage 2: Stabilization. > o Stage 3: Bug fixes only. > * Work that spans multiple GCC stages is done on CVS branches in > the > main FSF repository. > * I will present at the next Gelato conference. I'll describe > GCC's > internals, its development process, what is going on and what > needs to be done.
