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Re: Proposed targets to obsolete for 3.5, first pass


[Cc'd to the SIMH development list to give them a heads-up...]

Steven Bosscher wrote:

[snip]

PROPOSED LIST OF TARGETS TO BE OBSOLETED FOR GCC 3.5

[snip]


vax-*
  The most recent post of someone interested in the VAX was in April
  last year[4], and it looked more like a joke than a serious interest
  in the port (but you really should have look at the pictures of the
  guy's "micro"-VAX box: http://williambader.com/museum/vax/vax.html).
  Everone knows VAX is old.  Nobody has been manufacturing VAXes
  since 1992.  There is no known free simulator, it is does not have
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Your arguments are generally sound, but let me update your knowledge.
There is a free simulator for the VAX, called SIMH:

http://simh.trailing-edge.com/

The SIMH project simulates a variety of old systems, including many DEC
machines.  VAX simulation was first added over two years ago and has been
under active development ever since.  I don't know if the simulator would
be easily usable for GCC testing, however.

I am not arguing for continuing VAX support, just providing some more
information to consider.

When I last looked at the VAX backend (several years ago, but I doubt
it's changed much), I thought it would have been much better if rewritten
from scratch.  So perhaps obsoleting the target for now would be a blessing
anyway, if someone would then modernize it.  Not even considering the cc0
issue, the VAX backend had almost no real concept of the different VAX
implementations and their performance characteristics, so it wouldn't have
generated very good code for some machines.  I think the authors mostly just
wanted something that worked.

  any ELF targets, it has a cc0 backend, and the most recent test
  results I could find are more than two years old[5].
  For GCC 3.4, vax-*-* was already obsoleted.  I'm not sure why vax-*
  should stay, and I couldn't figure it out from earlier discussions.

  [4] http://gcc.gnu.org/ml/gcc/2003-03/msg00721.html
  [5] http://gcc.gnu.org/ml/gcc-testresults/2002-09/msg00774.html

[snip]


The above list is somewhat different than earlier obsoleted target lists
in that I have focused on architectures that are either very old or poorly maintained. This is still very aggressive in the view of many
of y'all. The reason for my choices is that I really don't believe gcc
has to carry around so much old stuff for newer releases. Really, who
_has_ to to use gcc 3.5 to compile for, say, VAX? Should all gcc
contributors be burdened with the maintainance costs of such very old
targets?

[snip]


Colin


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