> -----Original Message----- > From: Steven Bosscher [mailto:[EMAIL PROTECTED] > Sent: Tuesday, May 01, 2007 4:09 PM > To: Sjodin, Jan > Cc: Diego Novillo; Joseph S. Myers; Ian Lance Taylor; gcc@gcc.gnu.org > Subject: Re: Information about LTO > > On 5/1/07, Sjodin, Jan <[EMAIL PROTECTED]> wrote: > > Can someone give similar information about LTO? How many people > > (full/part time) and how long time it will take? How much work is LTO > > compared to the tuple representation? > > A vast amount more if we're going to work on LTO with the current > GIMPLE representation, because we'll end up rewriting almost all of it > when the tuples representation is merged. > > ;-) > > More seriously: LTO is, by my uneducated guess, about the same amount > of work as the tuples work. I'm assuming single-language LTO here, > because cross-language LTO is far harder (by the time we get there, > we'll be talking about fixing the Fortran front end to play nice with > the call graph, defining some kind of type system, etc.). > > Personally, I think the most useful thing you could do at this point, > is helping with the tuples repesentation, or helping with the > preparations for LTO such as removing lang_hooks and perhaps some > intermediate representation oddities like early uses of DECL_RTL (for > e.g. register variables). I think Kenny has shown that an IL > reader/writer is not an awful lot of work, but IMHO it will be corner > cases like the ones I just mention that will take a little while to > resolve. So, better start early, to make work easier later on. > > But as I said, that's just my uneducated guess. I haven't done any > LTO work myself yet ;-) > > Gr. > Stevem >
Thanks for all the responses. It seems like LTO will have to wait for the tuples or there will be a lot of throw-away code. - Jan
