From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Zack Weinberg" <zackw@stanford.edu>
To: Andy Walker <jawalker@stl.quik.com>
Cc: GCC general mailing list <gcc@gcc.gnu.org>
Subject: Re: Hashing of "switch/case" selections
Date: Thu, 04 Jan 2001 01:39:00 -0000
Message-id: <20010104013910.F12948@wolery.stanford.edu>
References: <3A4AC4FC.35E70BEE@stl.quik.com>
X-SW-Source: 2001-01/msg00167.html

On Wed, Dec 27, 2000 at 10:43:40PM -0600, Andy Walker wrote:
[much interesting stuff]
> My experience as a programmer is that programs are almost never written
> with switches to more than a few hundred cases.  I personally have never
> seen one.  More than that, and the programmer finds a more efficient,
> more readable, more maintainable solution, and he can do so because he
> has a deep knowledge of the problem that is unavailable to the
> compiler.  My seat-of-pants estimate is that 400 cases is a good, maybe
> even high, maximum for Hash evaluations.  A program containing a switch
> statement with more than 400 cases in it probably has enough other
> severe design problems that it will never be worth running anyway.

This is true in my experience for code written by humans, but not
necessarily for machine-generated code.  Take a look at insn-attrtab.c
in your GCC build directory, or at cp/parse.c in the source tree.

zw