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From: poser@csli.stanford.edu (Bill Poser)
Newsgroups: comp.compilers
Subject: Re: Unsafe Optimizations (WAS: Compiler Design in C How about it?)
Keywords: optimize, C
Message-ID: <1990Jun6.032145.5495@esegue.segue.boston.ma.us>
Date: 6 Jun 90 03:21:45 GMT
References: <1990Jun4.044255.14857@esegue.segue.boston.ma.us> <1990Jun1.194941.5781@esegue.segue.boston.ma.us> <1990Jun4.212226.18389@esegue.segue.boston.ma.us>
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Reply-To: poser@csli.stanford.edu (Bill Poser)
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In article <1990Jun4.212226.18389@esegue.segue.boston.ma.us> larus@spool.cs.wisc.edu writes:
>Some programmers are willing to trade off the semantics of the language (the
>effect of "bad" optimizations) for faster programs. 

This misses the point. If you want to define a new version of a language
for parallel execution and specify how the semantics differs from
the sequential version of the language, fine. Then the programmer knows
what he is getting into. The problem with dangerous optimization is that
it changes the semantics behind the programmer's back. Such changes
are known as "errors".

							Bill
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