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Ian Romanick e71eb0f2ea intel/fs: sel.cond writes the flags on Gfx4 and Gfx5
On Gfx4 and Gfx5, sel.l (for min) and sel.ge (for max) are implemented
using a separte cmpn and sel instruction.  This lowering occurs in
fs_vistor::lower_minmax which is called very, very late... a long, long
time after the first calls to opt_cmod_propagation.  As a result,
conditional modifiers can be incorrectly propagated across sel.cond on
those platforms.

No tests were affected by this change, and I find that quite shocking.
After just changing flags_written(), all of the atan tests started
failing on ILK.  That required the change in cmod_propagatin (and the
addition of the prop_across_into_sel_gfx5 unit test).

Shader-db results for ILK and GM45 are below.  I looked at a couple
before and after shaders... and every case that I looked at had
experienced incorrect cmod propagation.  This affected a LOT of apps!
Euro Truck Simulator 2, The Talos Principle, Serious Sam 3, Sanctum 2,
Gang Beasts, and on and on... :(

I discovered this bug while working on a couple new optimization
passes.  One of the passes attempts to remove condition modifiers that
are never used.  The pass made no progress except on ILK and GM45.
After investigating a couple of the affected shaders, I noticed that
the code in those shaders looked wrong... investigation led to this
cause.

v2: Trivial changes in the unit tests.

v3: Fix type in comment in unit tests.  Noticed by Jason and Priit.

v4: Tweak handling of BRW_OPCODE_SEL special case.  Suggested by Jason.

Fixes: df1aec763e ("i965/fs: Define methods to calculate the flag subset read or written by an fs_inst.")
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Tested-by: Dave Airlie <airlied@redhat.com>

Iron Lake
total instructions in shared programs: 8180493 -> 8181781 (0.02%)
instructions in affected programs: 541796 -> 543084 (0.24%)
helped: 28
HURT: 1158
helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1
helped stats (rel) min: 0.35% max: 0.86% x̄: 0.53% x̃: 0.50%
HURT stats (abs)   min: 1 max: 3 x̄: 1.14 x̃: 1
HURT stats (rel)   min: 0.12% max: 4.00% x̄: 0.37% x̃: 0.23%
95% mean confidence interval for instructions value: 1.06 1.11
95% mean confidence interval for instructions %-change: 0.31% 0.38%
Instructions are HURT.

total cycles in shared programs: 239420470 -> 239421690 (<.01%)
cycles in affected programs: 2925992 -> 2927212 (0.04%)
helped: 49
HURT: 157
helped stats (abs) min: 2 max: 284 x̄: 62.69 x̃: 70
helped stats (rel) min: 0.04% max: 6.20% x̄: 1.68% x̃: 1.96%
HURT stats (abs)   min: 2 max: 48 x̄: 27.34 x̃: 24
HURT stats (rel)   min: 0.02% max: 2.91% x̄: 0.31% x̃: 0.20%
95% mean confidence interval for cycles value: -0.80 12.64
95% mean confidence interval for cycles %-change: -0.31% <.01%
Inconclusive result (value mean confidence interval includes 0).

GM45
total instructions in shared programs: 4985517 -> 4986207 (0.01%)
instructions in affected programs: 306935 -> 307625 (0.22%)
helped: 14
HURT: 625
helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1
helped stats (rel) min: 0.35% max: 0.82% x̄: 0.52% x̃: 0.49%
HURT stats (abs)   min: 1 max: 3 x̄: 1.13 x̃: 1
HURT stats (rel)   min: 0.12% max: 3.90% x̄: 0.34% x̃: 0.22%
95% mean confidence interval for instructions value: 1.04 1.12
95% mean confidence interval for instructions %-change: 0.29% 0.36%
Instructions are HURT.

total cycles in shared programs: 153827268 -> 153828052 (<.01%)
cycles in affected programs: 1669290 -> 1670074 (0.05%)
helped: 24
HURT: 84
helped stats (abs) min: 2 max: 232 x̄: 64.33 x̃: 67
helped stats (rel) min: 0.04% max: 4.62% x̄: 1.60% x̃: 1.94%
HURT stats (abs)   min: 2 max: 48 x̄: 27.71 x̃: 24
HURT stats (rel)   min: 0.02% max: 2.66% x̄: 0.34% x̃: 0.14%
95% mean confidence interval for cycles value: -1.94 16.46
95% mean confidence interval for cycles %-change: -0.29% 0.11%
Inconclusive result (value mean confidence interval includes 0).

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12330>
2021-08-12 06:31:23 +10:00
.gitlab/issue_templates issue_templates/Bug Report: Rename master branch to main 2021-05-05 12:20:11 -07:00
.gitlab-ci ci: actually run piglit tests with virgl 2021-07-21 11:53:48 -07:00
android android: Restore android/Android.mk 2021-07-09 13:54:45 +00:00
bin bin/gen_release_notes: Fix commits with multiple Closes: 2021-08-05 09:26:05 -07:00
build-support configure: commit test files 2017-10-16 16:32:43 -07:00
docs docs: Add sha256 sum for 21.2.0 2021-08-04 12:07:28 -07:00
include crocus: Make the driver loader use PCI IDs for crocus 2021-07-03 06:34:33 +02:00
src intel/fs: sel.cond writes the flags on Gfx4 and Gfx5 2021-08-12 06:31:23 +10:00
subprojects util: Perfetto SDK v15.0 2021-05-07 13:41:38 +00:00
.dir-locals.el dir-locals.el: Adds White Space support 2016-11-14 19:17:49 +02:00
.editorconfig editorconfig: Use 3-space tabs for .rst 2021-06-22 17:37:55 +00:00
.gitignore intel/tools: Add unit tests for assembler 2019-05-07 14:33:48 -07:00
.gitlab-ci.yml ci: Drop "success" job 2021-08-05 09:25:17 -07:00
.mailmap mailmap: Add two more lines for Alyssa Rosenzweig 2021-07-12 23:45:34 +00:00
.pick_status.json radv: Use correct signedness in misalign test. 2021-08-10 11:16:50 -07:00
.travis.yml travis: Download XQuartz from GitHub. 2021-05-29 10:25:16 +00:00
meson.build meson: dont use missing dumpbin path 2021-08-02 13:30:04 -07:00
meson_options.txt meson: allow egl_native_platform to be specified 2021-07-26 12:01:54 -07:00
README.rst docs: promote #dri-devel on oftc over freenode 2021-05-24 09:21:48 +00:00
REVIEWERS Fix up leftover "state_trackers" references to "frontends" 2021-07-02 07:35:05 +00:00
VERSION VERSION: bump for 21.2.0 release 2021-08-04 11:47:36 -07:00

`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 `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.