Thanks for your explain. I see, you want to generate the dominator first. Chris On Tue, Dec 12, 2006 at 08:36:43AM -0800, Linus Torvalds wrote: > > > On Tue, 12 Dec 2006, Christopher Li wrote: > > They don't have to. But it generated nicer code, iirc, mainly because it > did the storage allocation the natural way. In particular, if I recall > correctly, it causes loops to have the storage for the _innermost_ loop to > be done first. > > Notes off the top of my head, without actually looking at the code: > because when you hit a loop, the "parent" set is actually both the entry > and the BB that ha the loopback, so you actually end up going to the > loopback thing, which goes to _its_ parents, etc etc, until you actually > get back to the _top_ of the loop (and now the "generation" count triggers > you to break the looping), so you end up doing the actual register > allocation at tops of loops, but because you do this all recursively, and > the inner loop will have _its_ parents point to the callback too, you > generally tend to have started storage allocation at loop-tops. > > HOWEVER. There's a reason the thing is called "example.c". The reason is > simply that it's stupid, idiotic, and not meant to be taken seriously. I > also ended up just hackign things around randomly to make it output > something that looked half-way sane, _and_ I ended up changign it to use > the "unssa" pass by Luc, _and_ I'm border-line psychotic when it comes to > compilers anyway. > > In other words, what I'm trying to say is that you shouldn't take anything > I say too seriously, and that the "example.c" code wasn't really even > meant to be serious. I always wanted somebody else to write the back-end, > and held back as long as I could from writing example.c, and when I wrote > it, it was more a case of desperately trying to find somebody interested > in it, and having it as an example of how things _might_ work. > > So as far as I am concerned, the whole "example.c" is just total > throw-away code. Go wild with it. > > Linus - To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
