Re: Multibyte/Wide Character Sets and Lex.

jfc@mit.edu (John Carr)
14 Feb 1996 21:30:11 -0500

          From comp.compilers
Related articles
[2 earlier articles]
Re: Multibyte/Wide Character Sets and Lex. sharris@fox.nstn.ca (Sandy Harris) (1996-02-10)
Re: Multibyte/Wide Character Sets and Lex. schwartz@galapagos.cse.psu.edu (1996-02-12)
Re: Multibyte/Wide Character Sets and Lex. pjbumbul@math.uwaterloo.ca (1996-02-13)
Re: Multibyte/Wide Character Sets and Lex. fjh@cs.mu.OZ.AU (1996-02-13)
Re: Multibyte/Wide Character Sets and Lex. peter@csgrs6k1.uwaterloo.ca (1996-02-14)
Re: Multibyte/Wide Character Sets and Lex. mparks@oz.net (Michael Parkes) (1996-02-14)
Re: Multibyte/Wide Character Sets and Lex. jfc@mit.edu (1996-02-14)
| List of all articles for this month |
From: jfc@mit.edu (John Carr)
Newsgroups: comp.compilers
Date: 14 Feb 1996 21:30:11 -0500
Organization: Massachusetts Institute Of Technology
References: 96-02-065 96-02-135
Keywords: lex, optimize



>re2c can translate switch statements into nested ifs (usually a
>performance win.)


<fjh@cs.mu.OZ.AU> wrote:
>Why is this usually a performance win? If it is a performance win,
>why don't compilers do it automatically?


If the program generating the source code knows the probability
distribution of the value tested, it can optimize for the common case
(e.g. end-of-file and NUL are rare in text files, but a parser should
still be able to handle them).


--
        John Carr (jfc@mit.edu)
--

Post a followup to this message

Return to the comp.compilers page.
Search the comp.compilers archives again.