Find a file
Ian Romanick 7e127c1fca nir/algebraic: Fix some min/max of b2f replacements
fmin(-A, -B) is -fmax(A, B), and fmax(-A, -B) is -fmin(A, B).  Therefore
the logic joining A and B should toggle between ior and iand for the
negated versions.

At the very least, a shader from Euro Truck Simulator 2 in shader-db is
affected by this.  The KIL instruction in the (ARB assembly) shader ends
up with the wrong logic.  This is _probably_ the source of
https://gitlab.freedesktop.org/mesa/mesa/-/issues/1346.

That said, the issue mentions that Mesa 18.0.5 works, but commit
68420d8322 ("nir: Simplify min and max of b2f") was added in 17.3.
Moreover, I was not able to reproduce the error in the ETS2 shader from
shader-db from any Mesa commit near the time the original fd.o bugzilla
was submitted (December 2018). 🤷

In fact, the current error in that shader starts with 9167324a86
("nir/algebraic: Mark some logic-joined comparison reductions as
exact").  That's a bit of a red herring as 9167324a86 just sets off a
chain of replacements that eventually leads to the incorrect min/max of
b2f patterns fixed by this commit.

The other affected shaders in the shader-db results are from Cargo
Commander.  These are also ARB assembly shaders.

I think any ARB assembly shader that uses the pattern

    SLT    r0, ...;
    ...
    KIL    -r0;

will suffer from issues related to this.

This change fixes the piglit
tests/spec/arb_fragment_program/kil-of-slt.shader_test test added in
https://gitlab.freedesktop.org/mesa/piglit/-/merge_requests/454.

shader-db results:

All Gen6+ platforms had similar result. (Ice Lake shown)
total instructions in shared programs: 20034604 -> 20034486 (<.01%)
instructions in affected programs: 3885 -> 3767 (-3.04%)
helped: 47
HURT: 2
helped stats (abs) min: 2 max: 4 x̄: 2.64 x̃: 2
helped stats (rel) min: 2.33% max: 8.33% x̄: 3.48% x̃: 3.39%
HURT stats (abs)   min: 3 max: 3 x̄: 3.00 x̃: 3
HURT stats (rel)   min: 13.64% max: 16.67% x̄: 15.15% x̃: 15.15%
95% mean confidence interval for instructions value: -2.83 -1.99
95% mean confidence interval for instructions %-change: -3.84% -1.60%
Instructions are helped.

total cycles in shared programs: 979881379 -> 979879406 (<.01%)
cycles in affected programs: 119873 -> 117900 (-1.65%)
helped: 46
HURT: 3
helped stats (abs) min: 10 max: 756 x̄: 45.41 x̃: 26
helped stats (rel) min: 0.53% max: 19.72% x̄: 1.67% x̃: 1.26%
HURT stats (abs)   min: 28 max: 56 x̄: 38.67 x̃: 32
HURT stats (rel)   min: 1.44% max: 3.54% x̄: 2.75% x̃: 3.27%
95% mean confidence interval for cycles value: -70.83 -9.70
95% mean confidence interval for cycles %-change: -2.23% -0.57%
Cycles are helped.

Iron Lake and GM45 had similar results. (Iron Lake shown)
total instructions in shared programs: 8115098 -> 8115076 (<.01%)
instructions in affected programs: 2592 -> 2570 (-0.85%)
helped: 32
HURT: 2
helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1
helped stats (rel) min: 0.88% max: 2.70% x̄: 1.35% x̃: 1.31%
HURT stats (abs)   min: 5 max: 5 x̄: 5.00 x̃: 5
HURT stats (rel)   min: 17.24% max: 18.52% x̄: 17.88% x̃: 17.88%
95% mean confidence interval for instructions value: -1.15 -0.15
95% mean confidence interval for instructions %-change: -1.83% 1.39%
Inconclusive result (%-change mean confidence interval includes 0).

total cycles in shared programs: 238189718 -> 238189802 (<.01%)
cycles in affected programs: 75076 -> 75160 (0.11%)
helped: 3
HURT: 31
helped stats (abs) min: 2 max: 130 x̄: 44.67 x̃: 2
helped stats (rel) min: 0.18% max: 5.70% x̄: 2.02% x̃: 0.19%
HURT stats (abs)   min: 2 max: 70 x̄: 7.03 x̃: 4
HURT stats (rel)   min: 0.07% max: 6.41% x̄: 0.53% x̃: 0.15%
95% mean confidence interval for cycles value: -7.27 12.21
95% mean confidence interval for cycles %-change: -0.33% 0.94%
Inconclusive result (value mean confidence interval includes 0).

No fossil-db changes on any Intel platform.

Fixes: 68420d8322 ("nir: Simplify min and max of b2f")
Closes: #1346
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9122>
2021-02-19 17:30:53 -08:00
.appveyor appveyor: Use Python3. 2020-08-06 09:46:48 +00:00
.gitlab/issue_templates gitlab: add RADV bug report template 2020-12-18 08:03:04 +00:00
.gitlab-ci ci/freedreno: Add a fractional gles31 run with asan enabled. 2021-02-18 00:49:00 +00:00
bin bin/post_version: convert the csv.reader into a concrete list 2021-01-21 23:22:36 +00:00
build-support configure: commit test files 2017-10-16 16:32:43 -07:00
ci-expects turnip,freedreno/a6xx: tell hw the size of shared mem used by CS 2021-02-19 20:28:44 +02:00
docs zink: update relnotes 2021-02-19 03:20:39 +00:00
doxygen doxygen: Plumb through gallium/ to automated documentation 2016-05-30 17:53:45 +01:00
include vulkan: Update XML and headers to 1.2.168 2021-01-27 22:20:52 +00:00
scons Scons: check for timespec_get on windows as well as unices 2021-02-01 19:40:20 +00:00
src nir/algebraic: Fix some min/max of b2f replacements 2021-02-19 17:30:53 -08:00
subprojects d3d12: Use DirectX-Headers wrap for d3d12.h 2020-12-16 16:25:54 +00:00
.dir-locals.el dir-locals.el: Adds White Space support 2016-11-14 19:17:49 +02:00
.editorconfig docs: fixup indentation 2020-01-18 11:39:32 +01:00
.gitignore intel/tools: Add unit tests for assembler 2019-05-07 14:33:48 -07:00
.gitlab-ci.yml ci: Move specific driver testing to separate files in separate dirs. 2021-02-19 17:30:36 +00:00
.mailmap .mailmap: add and update aliases for Danylo Piliaiev 2020-12-04 15:08:30 +00:00
.travis.yml travis: autodetect python version instead of hard-coding it 2019-12-21 20:23:08 +00:00
Android.common.mk tree-wide: fix deprecated GitLab URLs 2020-05-23 15:33:50 +00:00
Android.mk ac/llvm: handle static/shared llvm init separately 2020-08-17 10:47:41 +00:00
appveyor.yml appveyor: Use Python3. 2020-08-06 09:46:48 +00:00
CleanSpec.mk CleanSpec.mk: Remove HOST_OUT_release 2018-08-02 15:42:40 -06:00
common.py scons: Print a deprecation warning about using scons on not windows 2019-10-24 18:33:50 +00:00
meson.build macros: Add thread-safety annotation macros 2021-02-18 00:27:49 +00:00
meson_options.txt meson: add enable-glcpp-tests option 2021-01-28 15:52:32 +00:00
README.rst README: update references to internal docs 2020-06-13 10:42:01 +00:00
REVIEWERS REVIEWERS: add VMware reviewers 2019-10-18 16:42:40 +00:00
SConstruct tree-wide: fix deprecated GitLab URLs 2020-05-23 15:33:50 +00:00
VERSION VERSION: bump for 21.1.0 cycle 2021-01-13 09:46:19 -08:00

`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 `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
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To figure out who you're talking to, or which nick to ping for your
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<https://dri.freedesktop.org/wiki/WhosWho/>`_.

The next best option is to ask your question in an email to the
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<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.