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Iago Toral Quiroga 9ca0e070e7 broadcom/compiler: optimize branch emission for uniform break/continue
A break/continue in a loop is typically emitted like this:

if (cond) {
    break/continue;
} else {
}

If cond is uniform, we'll emit code for a uniform if statement and
that will emit a branch right before the if to jump directly to the
else (or the block after the else in this case, since the else is
empty) in case cond evaluates to false. This means we end up emitting
two consecutive branch instructions, one before the if and one for the
THEN block right after:

branch(!cond) -> jump to else (or after else) if cond is false
nop
nop
nop
branch -> unconditional jump to break/continue
nop
nop
nop

Instead, if we are in this scenario, we can do better by emitting the
conditional jump directly and avoiding the "jump to else" case:

branch(cond) -> jump to break/continue if cond is true
nop
nop
nop

We need to be careful when emitting the break/continue for the case
where all lanes are disabled to avoid infinite loops: if we have a
break we always want to take the jump, but we don't want to take it
if it is a continue.

total instructions in shared programs: 13563672 -> 13557348 (-0.05%)
instructions in affected programs: 348034 -> 341710 (-1.82%)
helped: 1158
HURT: 10
Instructions are helped.

total uniforms in shared programs: 3779137 -> 3777535 (-0.04%)
uniforms in affected programs: 90583 -> 88981 (-1.77%)
helped: 1169
HURT: 0
Uniforms are helped.

total max-temps in shared programs: 2317670 -> 2317575 (<.01%)
max-temps in affected programs: 1943 -> 1848 (-4.89%)
helped: 85
HURT: 4
Max-temps are helped.

total sfu-stalls in shared programs: 32247 -> 32247 (0.00%)
sfu-stalls in affected programs: 69 -> 69 (0.00%)
helped: 7
HURT: 9
Inconclusive result (value mean confidence interval includes 0).

total inst-and-stalls in shared programs: 13595919 -> 13589595 (-0.05%)
inst-and-stalls in affected programs: 350674 -> 344350 (-1.80%)
helped: 1154
HURT: 11
Inst-and-stalls are helped.

total nops in shared programs: 358202 -> 354325 (-1.08%)
nops in affected programs: 17367 -> 13490 (-22.32%)
helped: 1168
HURT: 1
Nops are helped.

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9948>
2021-04-05 06:38:19 +00:00
.gitlab/issue_templates gitlab: rename RADV bug report template 2021-04-01 10:02:39 +00:00
.gitlab-ci ci/bare-metal: no need to use tee 2021-04-03 18:56:13 +00:00
bin bin/gen_release_notes.py: more robust rST escaping 2021-04-01 19:53:03 +00:00
build-support configure: commit test files 2017-10-16 16:32:43 -07:00
docs lavapipe: add support for KHR_imageless_framebuffer 2021-04-05 11:33:55 +10:00
doxygen doxygen: Plumb through gallium/ to automated documentation 2016-05-30 17:53:45 +01:00
include Remove Scons leftovers 2021-03-30 20:17:19 +00:00
src broadcom/compiler: optimize branch emission for uniform break/continue 2021-04-05 06:38:19 +00:00
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: Uprev piglit to 6a4be9e9946d ("piglit: NOTE! Default branch is now main") 2021-04-02 18:42:04 +00:00
.mailmap .mailmap: fix email for Daniel Schürmann 2021-03-22 18:56:22 +00:00
.travis.yml scons: Remove. 2021-03-20 10:38:55 +00:00
Android.common.mk meson, util: Make zlib optional again 2021-03-19 19:33:59 +00:00
Android.mk meson/gallium: Add an option to not use LLVM for gallium draw module 2021-02-25 17:48:16 +00:00
CleanSpec.mk CleanSpec.mk: Remove HOST_OUT_release 2018-08-02 15:42:40 -06:00
meson.build wgl: Add unit test infrastructure for OpenGL32.dll on Windows 2021-04-01 16:19:41 +00:00
meson_options.txt intel: Add null hw layer 2021-03-25 19:10:03 +00:00
README.rst README: update references to internal docs 2020-06-13 10:42:01 +00:00
REVIEWERS scons: Remove. 2021-03-20 10:38:55 +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
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.