We're out of tree codes; now what?

[gdr@cs.tamu.edu]

Quoting Mark Mitchell <mark@codesourcery.com>:

> Steven Bosscher wrote:
>
>> Let's be fair here: A 3% hit is small compared to the cumulative
>> slowdown we already have in GCC 4.3 since the start of stage 1, and
>> negligible compared to the total slowdown we've accumulated over the
>> years. I know this is not really an argument, but let's face it: Much
>> larger patches and branch merges have unintentionally increased
>> compile time by more than 3%, and we didn't have a large discussion
>> about it.
>
> Yes, that's true.  Here, however, we have two paths in front of us:
> 9-bit tree codes, or some language-dependent subcodes.  The benefit of
> 9-bit tree codes is that they're easy to understand; the benefit of
> subcodes is that they might be faster, but, then again, they might use
> more memory.  I'd be interested in understanding the tradeoff.

Does C++ front end really need to use tree codes for most of its
data structures?

Assuming we have a volunteer and resources to work on having the C++ front-end
stop using tree codes for most of its data structures, do you have an estimate
how much of tree code pressure will we left?

-- Gaby