[RFC] Merge criteria for tree-ssa

[Diego Novillo <dnovillo at redhat dot com>]

This is a preliminary list of issues that should be addressed prior to
merging tree-ssa into mainline.  I would appreciate feedback and
thoughts before I submit this to the SC.

In particular, I need information regarding Fortran.

By Feb/15, I would like declare the branch frozen.  Any major
changes we may have by then should wait until after the merge.

The post-merge TODO list is simpler:

  - Fix whatever broke.
  - Add major changes that were on hold before the merge.


Thanks.  Diego.

============================================================================

Documentation
-------------

  - New -f and --param command line options described in doc/invoke.texi.

  - New tree codes described in c-tree.texi.  We probably
    need at least two additional documentation files:
    generic-gimple.texi and tree-ssa.texi.

  - Verify function and file-level documentation to make sure
    it's up-to-date.

  - Rewrite passes.texi.  In particular the FE->optimizer interface.

  - Associated PRs: 13756.


Code Reviews
------------

  - Request code reviews for all the components of the branch.  I
    will draft a design document (which will be part of the .texi
    documentation mentioned above) to help people navigate the
    code.


Testing
-------

  - Bootstrap and tested with all languages except Ada, Fortran77
    and Treelang.  All of which will be considered broken after
    the merge.

  - Regression tests showing no regressions with respect to mainline
    before the merge.

  - Bootstrapped and tested on:
	alphaev67-unknown-linux-gnu
	i686-pc-linux-gnu
	x86_64-unknown-linux-gnu
	powerpc-unknown-linux-gnu
	ia64-unknown-linux-gnu
	[ Need to add at least a couple of popular embedded ports ]

  - Applications: glibc, gdb, mozilla, POOMA, DLV, linux kernel.
    [ perhaps this is too much for pre-merge criteria, we could
      do this post-merge, perhaps? ]

  - Associated PRs: 13951, 12454, 12807, 13755, 13769, 13066,
    13379.



Run Time Performance
--------------------

  - SPECint and SPECfp performance within 3% of mainline.

  - Associated PRs: 1046, 13751, 13758, 13759, 13761, 13765,
    13796, 13799, 13952, 13953, 13965, 2399, 8781, 9059, 9567,
    10050, 13954, 13962, 11761, 12747, 12814, 13643, 179, 6880,
    6883, 7688, 8935, 8936, 9540, 9566, 11680
    [ Note, many of these are already fixed in the branch. ]



Compile Time Performance
------------------------

  - Bootstrap times within 1-5% of mainline.

  - POOMA, DLV and MICO compile times within 1-5% of mainline.

  - Memory consumption within 1-5% of mainline (POOMA, DLV and
    MICO seem good tests).

  - Associated PRs: 13776, 13775.