Re: Effectiveness of compilers today

jbuck@forney.berkeley.edu (Joe Buck)
Wed, 17 Feb 1993 20:56:39 GMT

          From comp.compilers

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Newsgroups: comp.compilers
From: jbuck@forney.berkeley.edu (Joe Buck)
Keywords: optimize
Organization: U. C. Berkeley
References: 93-02-082 93-02-089
Date: Wed, 17 Feb 1993 20:56:39 GMT

Josh N. Pritikin <jpab+@andrew.cmu.edu> writes:
>Assembly programmers will never have job security! Take a look at the GNU
>superoptimizer ---


The GNU superoptimizer uses exhaustive search. This means that its
behavior is exponential. It can still be useful in certain circumstances
(find the best sequence to generate a certain small function), but it's
not going to put anyone out of business.


The sequences shown in your example are all four instructions or fewer.
How fast its performance degrades as more instructions are required
depends on how good its heuristics are, but you can't get away from the
combinatorial explosion.
--
Joe Buck jbuck@ohm.berkeley.edu
--


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