Connor Abbott
29a1450e28
Before this commit, there were two copies of the algorithm: one in C, that we would use to figure out what bit-size to give the replacement expression, and one in Python, that emulated the C one and tried to prove that the C algorithm would never fail to correctly assign bit-sizes. That seemed pretty fragile, and likely to fall over if we make any changes. Furthermore, the C code was really just recomputing more-or-less the same thing as the Python code every time. Instead, we can just store the results of the Python algorithm in the C datastructure, and consult it to compute the bitsize of each value, moving the "brains" entirely into Python. Since the Python algorithm no longer has to match C, it's also a lot easier to change it to something more closely approximating an actual type-inference algorithm. The algorithm used is based on Hindley-Milner, although deliberately weakened a little. It's a few more lines than the old one, judging by the diffstat, but I think it's easier to verify that it's correct while being as general as possible. We could split this up into two changes, first making the C code use the results of the Python code and then rewriting the Python algorithm, but since the old algorithm never tracked which variable each equivalence class, it would mean we'd have to add some non-trivial code which would then get thrown away. I think it's better to see the final state all at once, although I could also try splitting it up. v2: - Replace instances of "== None" and "!= None" with "is None" and "is not None". - Rename first_src to first_unsized_src - Only merge the destination with the first unsized source, since the sources have already been merged. - Add a comment explaining what nir_search_value::bit_size now means. v3: - Fix one last instance to use "is not" instead of != - Don't try to be so clever when choosing which error message to print based on whether we're in the search or replace expression. - Fix trailing whitespace. Reviewed-by: Jason Ekstrand <jason@jlekstrand.net> Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
`Mesa <https://mesa3d.org>`_ - The 3D Graphics Library
======================================================
Source
------
This repository lives at https://gitlab.freedesktop.org/mesa/mesa.
Other repositories are likely forks, and code found there is not supported.
Build status
------------
Travis:
.. image:: https://travis-ci.org/mesa3d/mesa.svg?branch=master
:target: https://travis-ci.org/mesa3d/mesa
Appveyor:
.. image:: https://img.shields.io/appveyor/ci/mesa3d/mesa.svg
:target: https://ci.appveyor.com/project/mesa3d/mesa
Coverity:
.. image:: https://scan.coverity.com/projects/139/badge.svg?flat=1
:target: https://scan.coverity.com/projects/mesa
Build & install
---------------
You can find more information in our documentation (`docs/install.html
<https://mesa3d.org/install.html>`_), but the recommended way is to use
Meson (`docs/meson.html <https://mesa3d.org/meson.html>`_):
.. code-block:: sh
$ mkdir build
$ cd build
$ meson ..
$ sudo ninja install
Support
-------
Many Mesa devs hang on IRC; if you're not sure which channel is
appropriate, you should ask your question on `Freenode's #dri-devel
<irc://chat.freenode.net#dri-devel>`_, someone will redirect you if
necessary.
Remember that not everyone is in the same timezone as you, so it might
take a while before someone qualified sees your question.
To figure out who you're talking to, or which nick to ping for your
question, check out `Who's Who on IRC
<https://dri.freedesktop.org/wiki/WhosWho/>`_.
The next best option is to ask your question in an email to the
mailing lists: `mesa-dev\@lists.freedesktop.org
<https://lists.freedesktop.org/mailman/listinfo/mesa-dev>`_
Bug reports
-----------
If you think something isn't working properly, please file a bug report
(`docs/bugs.html <https://mesa3d.org/bugs.html>`_).
Contributing
------------
Contributions are welcome, and step-by-step instructions can be found in our
documentation (`docs/submittingpatches.html
<https://mesa3d.org/submittingpatches.html>`_).
Note that Mesa uses email mailing-lists for patches submission, review and
discussions.