flow speed regression [Re: How long should -O1 compiles take?]

[Marc Feeley]

> On Wed, Oct 06, 1999 at 08:14:25AM -0500, Brad Lucier wrote:
> > Some applications really need a "pretty good" compiler that runs
> > relatively quickly.  For example, I believe that the fastest way
> > to do genetic programming on image data is to compile the evolving
> > programs before testing them.
> 
> If you really care about compile speed, the scheme output should be
> restructured to not use computed gotos.  Flow graphs with an edge/block
> ratio this high (463:1) simply _cannot_ be compiled quickly.
> 
> In fact, I bet it could be restructured so that the resulting code
> runs _faster_ than with computed gotos.

What do you have in mind here?  I've been looking for solutions for
the past 5 years and the computed gotos of gcc are currently the
fastest solution.  The best alternative, which has the advantage of
being portable to other C compilers, is a large switch statement but
that can be up to 3 times slower on a Pentium.

Marc Feeley