[RFC] WHOPR - A whole program optimizer framework for GCC

[Diego Novillo]

On 12/18/07 08:29, Jan Hubicka wrote:

> Doing call graph changes should not be that hard (I was trying to keep
> similar deisgn in mind when implementing it, even if we stepped away
> from the plan in some cases, like reorganizing passes from vertical to
> horisontal order). Nearest problem I see is merging different
> declarations of units read back, I have prototype implementation of DECL
> merging pass done from my trip this week and hope to have it working at
> least for --combine and C during christmas.

Cool.  Yeah, that is going to be one of the main things we need to 
continue.  For the next little while I will be working on finishing 
tuples, most of what remains are mechanical changes to get bootstraps 
going.  I will then work on tuning RTL generation.

Since we have these two ongoing branches (LTO and tuples) that will be 
used by whole program optimizer, I think we need to coordinate a little 
bit.  I wrote up a wiki page to keep all these things linked from one place.

http://gcc.gnu.org/wiki/whopr

I started a very incomplete implementation plan that I would like folks 
to help fill in.

Ken/Nathan, what are the major issues still missing in LTO?  I wrote up 
a couple, but I'm sure you guys have a much more complete list.

Jan, wrt the optimization plan coming out of the analysis phase, and the 
various pieces of header/summary information, what do you think are the 
major pieces we need?

In terms of branch mechanics, I'm initially tempted to do this 
implementation on a branch separate from tuples and lto.  This will 
allow us to merge both lto and tuples separately, as the rest of the 
optimizer is still a long ways away.  What do folks think?


Thanks.  Diego.