Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!yale!cmcl2!kramden.acf.nyu.edu!brnstnd
From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.lang.misc
Subject: Re: Aggressive optimization
Message-ID: <7659:Nov620:58:5990@kramden.acf.nyu.edu>
Date: 6 Nov 90 20:58:59 GMT
References: <2133:Nov607:16:1090@kramden.acf.nyu.edu> <5079@lanl.gov>
Organization: IR
Lines: 19

In article <5079@lanl.gov> jlg@lanl.gov (Jim Giles) writes:
> I have never made the claim that arrays _are_ as efficient as
> pointers.  I have made the claim that _most_ code I've seen are
> _faster_ with arrays.  I've also frequently pointed out that a
> _bad_ compiler can make anything happen.

Are you insinuating that Sun's optimizing compiler is a bad compiler?

> If a given implementation implements
> arrays slower, then it isn't state of the art.

I'd love to see your brilliant state-of-the-art solution. You're saying
that, the compiler can figure out rather general assertions about what
indices are going to be used where, and can generate code where the
pointers (arrays) are pre-indexed appropriately. Could one of you CS
types please illustrate to Jim that finding optimal addition chains in a
general computation is equivalent to solving the halting problem?

---Dan