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Francisco Jerez 03f6edd5b7 intel/fs: Add physical fall-through CFG edge for unconditional BREAK instruction.
This adds a missing CFG edge that represents a possible physical
control flow path the EU might take under some conditions which isn't
part of the logical CFG of the program.  This possibility shouldn't
have led to problems on platforms prior to Gfx12, since the missing
control flow edge cannot possibly influence liveness intervals.
However on Gfx12+ it becomes the compiler's responsibility to resolve
data dependencies across instructions, and the missing physical
control flow paths may lead to a WaR data hazard currently not visible
to the software scoreboard pass, which could lead to data corruption.

Worse, the possibility for this path to be taken by the EU increases
on Gfx12+ due to a hardware bug affecting EU fusion -- However the
same physical path can be potentially taken on earlier platforms as
well, so this patch extends the CFG on all platforms for consistency,
even though the lack of this edge shouldn't lead to any functional
issues on platforms earlier than Gfx12.  There are no shader-db
changes on earlier platforms, so there seems to be no disadvantage
from using the same CFG representation as on later platforms.

This issue has ben reported on TGL with the following conformance
test, thanks to Ian for bringing the FULSIM dependency check warning
to my attention:

   dEQP-VK.graphicsfuzz.spv-stable-pillars-volatile-nontemporal-store

Fixes: 4d1959e693 ("intel/cfg: Represent divergent control flow paths caused by non-uniform loop execution.")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/4940
Reported-by: Tapani Pälli <tapani.palli@intel.com>
Reported-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14248>
(cherry picked from commit e7470a40c5)
2021-12-29 20:56:29 +00:00
.gitlab/issue_templates issue_templates/Bug Report: Rename master branch to main 2021-05-05 12:20:11 -07:00
.gitlab-ci meson: Check arguments before adding. 2021-11-10 21:58:06 +00:00
android android: add support for classic dri-drivers (v2) 2021-12-17 22:30:50 +00:00
bin android_stub: update platform headers to include atrace 2021-10-09 00:42:32 +00:00
build-support configure: commit test files 2017-10-16 16:32:43 -07:00
docs docs: add release notes for 21.3.2 2021-12-17 22:31:13 +00:00
include intel: remove 2 preproduction pci-id for ADLS 2021-11-10 21:58:04 +00:00
src intel/fs: Add physical fall-through CFG edge for unconditional BREAK instruction. 2021-12-29 20:56:29 +00:00
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 meson: Check arguments before adding. 2021-11-10 21:58:06 +00:00
.mailmap mailmap: Add two more lines for Alyssa Rosenzweig 2021-07-12 23:45:34 +00:00
.pick_status.json intel/fs: Add physical fall-through CFG edge for unconditional BREAK instruction. 2021-12-29 20:56:29 +00:00
.travis.yml travis: Download XQuartz from GitHub. 2021-05-29 10:25:16 +00:00
CODEOWNERS CODEOWNERS: add @jenatali for Microsoft & D3D12 2021-10-06 22:52:05 +00:00
meson_options.txt meson_options: Bump max value of platform-sdk-version to 31 2021-10-06 12:05:22 +00:00
meson.build meson: correctly detect linker arguments 2021-12-17 22:30:50 +00:00
README.rst docs: promote #dri-devel on oftc over freenode 2021-05-24 09:21:48 +00:00
VERSION VERSION: bump for 21.3.2 2021-12-17 22:31:25 +00:00

`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.