Re: Compiler for Z80/6510

[Peter Milliken <peter.milliken@australia.boeing.com>]

G'Day Robert,

Robert Dewar wrote:
<snip>

> True, most people cannot write efficient assembler language,
> for any machine. And what you say is of course true for them,
> but the idea that wonderful modern compilers can generate
> amazing code better than skilled humans can is just plain wrong.

Would you care to comment then on the paper written by Lawlis and Elam
which was published in Tri-Ada '92 titled "Ada Outperforms Assembly: A
Case Study" where, in point 6, they draw conclusions such as: compiler
optimisation has reached such a state of the art that it can implement
"hundreds of heuristics from a library of knowledge in this area of
technology" and generate code which can "beat assembly code in both size
and performance"?

I am curious, on the one hand we have this paper (advertised in the Ada
Home page) and on the other hand, experienced compiler writers such as
yourself. These statements seem to contradict each other. I do not have
any experience in compiler writing but I have been prepared to accept
the paper at it's face value (having no way to confirm or deny :-)). Did
Lawlis and Elam get it wrong? Were they correct for their particular
circumstances and environment? I have shown the paper to non Ada
software engineers and received various responses, the worst being open
ridicule and statements that the paper must be a pure fabrication.

Thanks
Peter