🚀 go-pugleaf

In article <24232:Nov905:50:0690@kramden.acf.nyu.edu>, brnstnd@kramden.acf.nyu.edu (Dan Bernstein) writes:
|> In article <5351@lanl.gov> jlg@lanl.gov (Jim Giles) writes:
|> 
|> (Note that I have demonstrated in another article that Mike is wrong.)

Yeah, right.

|>   [ Jim waxes prolific: ]
|> > The only question is "can the compiler promote the add of the base
|> > of array 'x' up to the point where 'i' is precomputed and therefore
|> > get the same efficiency as the precomputed pointer?"  Turns out that
|> > this problem is not even NP, it's O(N^2) for languages which permit
|> > arbitrary GOTOs and it's O(N) for "structured" languages
|> 
|> I simply don't understand where you and Mike are getting this ridiculous
|> assertions from. What problems are you fantasizing you've solved here?
|> Where are your purported proofs?

Read a book, Dan.  You've chosen to ignore Jim's suggestion of the Aho, 
Sethi, and Ullman text, *in the very article you quote.*

Chapters 9 and 10 should clear up your confusion about reducible
flow graphs, conservative vs non-conservative optimizations, and 
various aspects of aliasing.  (Although the rest of the books is
also quite informative and would probably save this newsgroup
several megabytes of explanations.

-- 
Mike Bolotski          Artificial Intelligence Laboratory, MIT
misha@ai.mit.edu       Cambridge, MA