Alyssa Rosenzweig
3df5446cbd
In the current IR, any register may be preloaded by reading it anywhere, and any register may be precoloured by writing it anywhere. This is convenient for instruction selection, but requires the register allocator to do considerable gymnastics to ensure it doesn't clobber precoloured registers. It also breaks the purity of our SSA representation, which complicates optimization passes (e.g. copyprop). Let's trade some instruction selection complexity for simplifying register allocation by constraining how register precolouring works. Under the new model: * Registers may only be preloaded at the start of the program. * Precoloured destinations are handled explicitly by RA. Internally, a stronger invariant is placed for preloading: registers may only be preloaded by MOV.i32 instructions at the beginning of the block, and these moves must be unique. These invariants ensure RA can trivially coalesce the moves. A bi_preload helper is added as a safe version of bi_register respecting these invariants, allowing a smooth transition for instruction selection. Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16585>
`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.rst <https://mesa3d.org/install.html>`_), but the recommended way is to use Meson (`docs/meson.rst <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 `OFTC's #dri-devel <irc://irc.oftc.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.rst <https://mesa3d.org/bugs.html>`_). Contributing ------------ Contributions are welcome, and step-by-step instructions can be found in our documentation (`docs/submittingpatches.rst <https://mesa3d.org/submittingpatches.html>`_). Note that Mesa uses gitlab for patches submission, review and discussions.