Re: GCC Status (2004-08-09)

[Steven Bosscher <stevenb at suse dot de>]

On Wednesday 11 August 2004 23:24, Mark Mitchell wrote:
> Geoffrey Keating wrote:
> >I would suggest that if we're going to go into stage 3, but still
> >allow patches for compile speed, code quality, and bug fixing, we
> >might as well call it stage 2.
>
> Problems with compile speed and code quality are bugs.

Ripping out and replacing whole passes otoh are not bug fixes.

> The mechanism we have for advancing quality is to restrict check-ins.
> That is basically the only mechanism we have.  As long as we are in
> stage 2, experience has shown that we will make relatively little
> progress fixing bugs.  It is not until the only way to make progress is
> to fix bugs -- rather than add features -- that we seem to get much
> traction there.  And, even then, a few people tend to fix most of the
> bugs -- including lots that they did not cause.

The question I think we need to answer first is, is mainline ready
to go in bug fix mode. IMVHO it's not.

As Kenner pointed out, there are still a lot of pending patches for new
passes that we really do need.  Also there are some existing passes that
may need some major surgery.
Then, we have have a very serious compile time problem, look at the SPEC
tester from Diego, for example.  So far tree-ssa has only added passes
and has not made it possible to obsolete existing compile time hogs in
the RTL optimizers.  Patches to improve this (like Dan Berlin's aliasing
work) are not ready yet.

And last time I tried, mainline can't even build a linux kernel with
4k stacks (because BIND_EXPRs are gone, the whole stack slot allocation
mechanism was broken, and recently was ripped out).

With so many known issues and pending works, why rush going to stage3?

Gr.
Steven