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From: guy@gorodish.UUCP
Newsgroups: comp.arch,comp.lang.c
Subject: Re: Optimization vs. the programmer
Message-ID: <16294@sun.uucp>
Date: Tue, 7-Apr-87 13:10:45 EST
Article-I.D.: sun.16294
Posted: Tue Apr  7 13:10:45 1987
Date-Received: Sat, 11-Apr-87 00:36:13 EST
References: <479@danews.ATT.COM>
Sender: news@sun.uucp
Reply-To: guy@sun.UUCP (Guy Harris)
Organization: Sun Microsystems, Mountain View
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Xref: utgpu comp.arch:808 comp.lang.c:1508

>Please dear compiler writers, make the compiler do what I
>tell it (or at least have the courtesy to warn me about it).
>If hardware was perfect then I wouldn't have a gripe, but
>it ain't so I do.

That's a nice general request, and as such nearly useless.  What does
"do what I tell it" mean?  To what level of detail are you "telling
it"?  Do you think moving invariant computations out of loops is not
"doing what you tell it"?  What about strength reductions?  What
about eliminating assignments to dead variables?

Compiler writers simply can't anticipate every single potential
hardware problem that may crop up and that may require you to put in
code that is in principle redundant.