f4ef34f207
With 8 and 16-bit types and anything where we have to use non-trivial strides registersto deal with restrictions, we end up with things that look like partial writes even though we don't care about any values in the register except those written by that instruction. This is particularly important when dealing with loops because liveness sees is_partial_write and the fact that an old version from a previous loop iteration may be valid at that point and extends all purely partially written values to the entire loop. This commit adds a new UNDEF instruction which does nothing (the generator doesn't emit anything) but which does a fake write to the register. This informs liveness that we don't care about any values before that point so it won't consider those registers to be falsely live. We can safely emit UNDEF instructions for all SSA values that come in from NIR and nearly all temporaries generated by various stages of the compiler. In particular, we need to insert UNDEF instructions when we handle region restrictions because the newly allocated registers are almost guaranteed to be partially written. No shader-db changes. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110432 Reviewed-by: Matt Turner <mattst88@gmail.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 & 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.