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f75c83c4aa
Consider the loop:
float i = 0.0;
while (true) {
if (i != 0.0)
break;
i = i + 1.0;
}
This loop clearly executes exactly one time.
Some trickery is necessary to handle cases where the initial loop value
is very large and the increment is, by comparison, very small. From the
fenu_once test case,
float i = -604462909807314587353088.0;
while (true) {
if (i != -604462909807314587353088.0)
break;
i = i + 36028797018963968.0;
}
This loop should also execute exactly once, but this is much more
challenging to calculate due to precision issues.
Going towards smaller magnitude (i.e., adding a small positive value to
a large negative value) requires a smaller delta to make a difference
than going towards a larger magnitude. For this reason,
-604462909807314587353088.0 + 36028797018963968.0 !=
-604462909807314587353088.0, but -604462909807314587353088.0 +
-36028797018963968.0 == -604462909807314587353088.0. Math class is
tough.
No changes in shader-db or fossil-db.
v2: Fix major bug in checking result of the eval_const_binop(nir_op_feq,
...) discovered while developing fneu_once_easy unit test. Fix a typo in
the comment just above that. Add fneu_once_easy test.
v3: Skip the iteration count adjustment tests for nir_op_fenu and
nir_op_ine. Since the iteration count is either 1 or unknown, all this
function can do is add numerical error. Add fenu_once tests.
v4: Change the initial value in the fneu_once test from large positive
to large negative. Change check in get_iteration from nir_op_fsub to
nir_op_fadd. Both changes from discussion with M Henning. Also add some
more explanation in fneu_once.
v5: Rename test cases.
Fixes:
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|---|---|---|
| .github/workflows | ||
| .gitlab/issue_templates | ||
| .gitlab-ci | ||
| android | ||
| bin | ||
| build-support | ||
| docs | ||
| include | ||
| src | ||
| subprojects | ||
| .dir-locals.el | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| .gitlab-ci.yml | ||
| .graphqlrc.yml | ||
| .mailmap | ||
| CODEOWNERS | ||
| meson.build | ||
| meson_options.txt | ||
| README.rst | ||
| VERSION | ||
`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.