Alyssa Rosenzweig
34fcf6d479
Consider the IR: %0 = load_reg %1 = fneg %0 %2 = ffloor %1 %3 = bcsel .., .., %1 Because the fneg has both foldable and non-foldable users, nir/legacy does not fold the fneg into the load_reg. This ensures that the backend correctly emits a dedicated fneg instruction (with the load_reg folded in) for the bcsel to use. However, because the chasing helpers did not previously take other uses of a modifier into account, the helpers would fuse in the fneg to the ffloor. Except that doesn't work, because the load_reg instruction is supposed to be eliminated. So we end up with broken chased IR: 1 = fneg r0 2 = ffloor -NULL 3 = bcsel, ..., 1 The fix is easy: only fold modifiers into ALU instructions if the modifiers can be folded away. If we can't eliminate the modifier instruction altogether, it's not necessarily beneficial to fold it anyway from a register pressure perspective. So this is probably ok. With that check in place we get correct IR 1 = fneg r0 2 = ffloor 1 3 = bcsel, ..., 1 Fixes carchase/230.shader_test under softpipe. Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io> Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24116>
`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.