Re: Counting Bits

[jamiel@sybase.com (Jamie Lawrence)]

At  4:47 PM 07/07/94 +0100, Graham Toal wrote:

>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.

The only tool I have ever seen that created real results was a tool that
caused more headaches than solutions. (Inside, proprietary tool, can't
go into details) It only worked on its native platform  and one could
feed it up to about 4K of code to analyse.

In one test I fed it approx 60 lines of code. It built a database
of 1.2 gigabytes, crunched for about 20 days, and bombed. This repeated
for quite a while. Someone eventually got it to work, and it really
did provide a pretty optimal solution. I have to wonder if people could
have done it in less than 4 months...


-j
--
"Blah Blah Blah"
___________________________________________________________________
Jamie Lawrence                                  <jamiel@sybase.com>