From: "Perry E. Metzger" <perry@imsi.com>
Date: Fri, 8 Jul 94 06:16:28 PDT
To: gtoal@an-teallach.com (Graham Toal)
Subject: Re: Counting Bits
In-Reply-To: <199407071547.QAA09077@an-teallach.com>
Message-ID: <9407081316.AA05465@snark.imsi.com>
MIME-Version: 1.0
Content-Type: text/plain



Graham Toal says:
> PS I dunno what superoptimisizer Perry is talking about but I've
> never heard of a real one that works.  You have to feed in a complete
> machine description at register transfer level and i don't know if
> those exist for real machines; also the problem is almost certainly
> exponential time for a *guaranteed* solution as Perry claims is
> possible.

As I've noted, Henry Massalin invented the superoptimizer -- and it
works -- a much slower but publically available implementation that
Henry had nothing to do with is available from the FSF as "Gnu
Superopt".

Perry