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Path: utzoo!linus!decvax!wivax!apollo!alan
From: alan@apollo.UUCP (Alan Lehotsky)
Newsgroups: net.lang
Subject: Re: Superstition in Programmers
Message-ID: <224@apollo.UUCP>
Date: Mon, 9-Jan-84 10:37:15 EST
Article-I.D.: apollo.224
Posted: Mon Jan  9 10:37:15 1984
Date-Received: Tue, 10-Jan-84 00:37:53 EST
References: <448@bbncca.ARPA>
Organization: Apollo Computer, Chelmsford, Mass.
Lines: 20

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On the subject of "down-counting" and comparisons such as
"x<0" versus "x=-1", a good compiler would analyze what you
did and write the optimal tests in many situations.

I say this, because VAX-11 BLISS does exactly this trick.  This
kind of thing is exactly what I have against C, in that it is
a language for optimizing programmers; in that it encourages
the programmer to have a model of the machine which supports
such notions as auto-increment and decrement (which may not have
hardware support!), user-declared REGISTERs, rather than just
letting the compiler figure out what the best things in
registers would be, etc...  BLISS allowed you to do all these
things, if you were either PERVERSE, or actually smarter than
the compiler.  It's just that you got good code EVEN when you
didn't have intimate knowledge of the machine architecture.
And furthermore, when you recompiled using BLISS-36 (for the DEC-10)
or BLISS-16 (for the PDP-11), you still got good code!