bootstrap problems

[Jan Hubicka <jh at suse dot cz>]

Hi,
Just to introduce - my recent changes to subreg handling has added some
extra sanity checking code, that found some latent bugs around the code
(the paradoxical subreg combining problems for instance). Currently the
PPC/i386 bootstrap passes fluently, but mips bootstrap still rings.

This is definitly problem for people doing development on the mips machine
and is really unfortunate.  Jeffrey has suggested to revert the patch,
but I believe this is not best solution for few purposes:
1) the patch is not buggy by itself in some point of view - just traps latent
   bug and as it is IMO good.
2) similar situation has happened about the conditional code revertion code.
   The patch has been reverted, the latent problem remains to my best knowledge
   (see PR 3053)

So I am thinking about alternate way around this.  One way is to branch between
stable and development tree, but we already do have such branch.
Other way that goes to my mind is to add tags "target-bootstrap" and
use scripts to move them each time the bootstrap on given target suceeds
for some write-access maitainer.

Then people not interested in having bootstrap problem all the time will just
use the tag. Maitainers can always try to update to latest and see if there
is problem or not.

What do you think about that?
Honza