closes#180171
part of #177259
Here are some extra changes apart from the usual which were needed
1. `libc/src/__support/FPUtil/generic/add_sub.h` → +0 -0 error
2. `libc/src/__support/FPUtil/generic/FMA.h` → implemented to handle
fmabf16(Normal,Normal,+/-INF)
```jsx
/home/runner/work/llvm-project/llvm-project/libc/test/src/math/fmabf16_test.cpp:62: FAILURE
Failed to match __llvm_libc_23_0_0_git::fmabf16(x, y, z) against LIBC_NAMESPACE::testing::mpfr::get_mpfr_matcher<mpfr::Operation::Fma>( input, __llvm_libc_23_0_0_git::fmabf16(x, y, z), 0.5, mpfr::RoundingMode::Nearest).
Input decimal: x: 338953138925153547590470800371487866880.00000000000000000000000000000000000000000000000000 y: 338953138925153547590470800371487866880.00000000000000000000000000000000000000000000000000 z: -inf
First input bits: 0x7F7F = (S: 0, E: 0x00FE, M: 0x007F)
Second input bits: 0x7F7F = (S: 0, E: 0x00FE, M: 0x007F)
Third input bits: (-Infinity)
Libc result: nan
MPFR result: -inf
Libc floating point result bits: (NaN)
MPFR rounded bits: (-Infinity)
```
1. ~~`libc/src/__support/FPUtil/bfloat16.h` → to handle *= operator for
Bfloat16 ( uses the already available mult operator)~~
moved to #182882
The exhaustive test currently includes subnormal range and for checking
for specific edge cases . This is due to the repeated failure at <2^32
input space specifically only for ubuntu 24.04 and 24.04-arm
The removed tests included -> PositiveRange and NegativeRange for
Normals and an extra positive test for subnormals/Denormals
Let me know if there are any changes expected or anything I missed in
this .
cc: @lntue @krishna2803 @overmighty
Switch the libc documentation site from the alabaster theme to Furo,
which provides mobile-friendly layout, a collapsible sidebar with
caption-based section grouping, and built-in "Edit this page" links.
Changes by area:
conf.py
- Switch html_theme to "furo"
- Add myst_parser extension (already in llvm/docs/requirements.txt, used
by LLDB/Clang/LLVM docs) to allow Markdown alongside RST
- Accept both .rst and .md source suffixes
- Configure Furo source_repository/source_branch/source_directory for
"Edit this page" links pointing to GitHub
- Wire _static/copybutton.{js,css} for copy-to-clipboard buttons on code
blocks (no new pip dependency; can migrate to sphinx-copybutton later
once it's in requirements-hashed.txt)
- Exclude plan-docs.md and Helpers/ from Sphinx processing
index.rst
- Rewrite landing page: remove apologetic "not fully complete" note, add
"What Works Today" section with concrete supported use cases, honest
caveat that full C stdlib coverage is still in progress
- Restructure hidden toctrees into five captioned sidebar groups: "Using
LLVM-libc", "Platforms" (GPU/UEFI promoted to top-level),
"Implementation Status", "Development", "Links"
New files
- docs/_static/copybutton.{js,css}: lightweight copy button for code
blocks
- docs/_static/custom.css: add status badge styles (.badge-complete
etc.) for use with Helpers/Styles.rst substitutions in later phases
Prepare for future status badges:
- docs/Helpers/Styles.rst: RST substitution definitions for status
badges (|Complete|, |Partial|, |InProgress|, |NotStarted|, |GPUOnly|,
|LinuxOnly|) — excluded from toctree, available for Phase 5+ pages
- docs/dev/building_docs.rst: new page covering prerequisites (with
Debian apt-first instructions), CMake flags, ninja docs-libc-html, the
docgen auto-generation pipeline, and troubleshooting
Removed
- docs/README.txt: stale file claiming Sphinx 1.1.3, not in any toctree;
superseded by docs/dev/building_docs.rst
Cleanups
- Remove redundant ".. contents:: Table of Contents" directives from 16
RST files (Furo renders its own per-page TOC in the sidebar)
- Remove same directive from libc/Maintainers.rst (pulled into docs via
include)
Implementing `asinpi` for single-precision. it continues what is done in
#152690 that implemented `asinpif16` with header-only approach that is
followed since #147386
Closes#159614
**Changes:**
- Initial implementation of rsqrt for single precision float
**Some small unrelated style changes to this PR (that I missed in my
rsqrtf16 PR):**
- Added extra - to the top comments to make it look nicer in
libc/shared/math/rsqrtf16.h
- Put rsqrtf16 inside of libc/src/__support/math/CMakeLists.txt in
sorted order
- Rearanged libc_math_function rsqrtf16 in Bazel to match alphabetical
order
This patch enhances the GPU support documentation page (`support.html`)
by adding a new, detailed section for `math.h`. This new section
presents the results of the GPU math conformance tests, providing
quantitative data on the accuracy of the supported higher math
functions.
This PR adds the following basic math functions for BFloat16 type along
with the tests:
- scalbnbf16
- scalblnbf16
---------
Signed-off-by: Krishna Pandey <kpandey81930@gmail.com>
This PR adds the following basic math functions for BFloat16 type along
with the tests:
- totalorderbf16
- totalordermagbf16
---------
Signed-off-by: Krishna Pandey <kpandey81930@gmail.com>
This PR adds the following basic math functions for BFloat16 type along
with the tests:
- canonicalizebf16
- iscanonicalbf16
- fdimbf16
- copysignbf16
- issignalingbf16
---------
Signed-off-by: Krishna Pandey <kpandey81930@gmail.com>
This PR adds the following basic math functions for BFloat16 type along
with the tests:
- modfbf16
- remainderbf16
- remquobf16
---------
Signed-off-by: Krishna Pandey <kpandey81930@gmail.com>
Co-authored-by: OverMighty <its.overmighty@gmail.com>
This PR adds the following basic math functions for BFloat16 type along
with the tests:
- frexpbf16
- ilobbf16
- ldexpbf16
- llogbbf16
- logbbf16
---------
Signed-off-by: Krishna Pandey <kpandey81930@gmail.com>
This PR adds the following basic math functions for BFloat16 type along
with the tests:
- nearbyintbf16
- rintbf16
- lrintbf16
- llrintbf16
- lroundbf16
- llroundbf16
---------
Signed-off-by: Krishna Pandey <kpandey81930@gmail.com>
This PR adds the following basic math functions for BFloat16 type along
with the tests:
- getpayloadbf16
- setpayloadbf16
- setpayloadsigbf16
---------
Signed-off-by: Krishna Pandey <kpandey81930@gmail.com>
This PR adds the following basic math functions for BFloat16 type along
with the tests:
- nextafterbf16
- nextdownbf16
- nexttowardbf16
- nextupbf16
---------
Signed-off-by: Krishna Pandey <kpandey81930@gmail.com>
Co-authored-by: OverMighty <its.overmighty@gmail.com>
This PR adds the following basic math functions for BFloat16 type along
with the tests:
- fromfpbf16
- fromfpxbf16
- ufromfpbf16
- ufromfpxbf16
---------
Signed-off-by: Krishna Pandey <kpandey81930@gmail.com>
Reverts llvm/llvm-project#146226
The MPFR test uses `mpfr_asinpi` which requires MPFR 4.2.0 or later, but
the Buildbots are running an older version of MPFR.
See https://lab.llvm.org/buildbot/#/builders/104/builds/27743 for
example.
I said I was going to revert the PR until we have a workaround for older
versions of MPFR, but then I forgot and I just disabled the entrypoints
which doesn't fix the Buildbot builds.
The function is implemented using the following Taylor series that's
generated using [python-sympy](https://www.sympy.org/en/index.html), and
it is very accurate for |x| $$\in [0, 0.5]$$ and has been verified using
Geogebra. The range reduction is used for the rest range (0.5, 1].
$$
\frac{\arcsin(x)}{\pi} \approx
\begin{aligned}[t]
& 0.318309886183791x \\
& + 0.0530516476972984x^3 \\
& + 0.0238732414637843x^5 \\
& + 0.0142102627760621x^7 \\
& + 0.00967087327815336x^9 \\
& + 0.00712127941391293x^{11} \\
& + 0.00552355646848375x^{13} \\
& + 0.00444514782463692x^{15} \\
& + 0.00367705242846804x^{17} \\
& + 0.00310721681820837x^{19} + O(x^{21})
\end{aligned}
$$
## Geogebra graph
Closes#132210
Main algorithm:
The Taylor series expansion of `asin(x)` is:
```math
\begin{align*}
asin(x) &= x + x^3 / 6 + 3x^5 / 40 + ... \\
&= x \cdot P(x^2) \\
&= x \cdot P(u) &\text{, where } u = x^2.
\end{align*}
```
For the fast path, we perform range reduction mod 1/64 and use degree-7
(minimax + Taylor) polynomials to approximate `P(x^2)`.
When `|x| >= 0.5`, we use the transformation:
```math
u = \frac{1 + x}{2}
```
and apply half-angle formula to reduce `asin(x)` to:
```math
\begin{align*}
asin(x) &= sign(x) \cdot \left( \frac{\pi}{2} - 2 \cdot asin(\sqrt{u}) \right) \\
&= sign(x) \cdot \left( \frac{\pi}{2} - 2 \cdot \sqrt{u} \cdot P(u) \right).
\end{align*}
```
Since `0.5 <= |x| <= 1`, `|u| <= 0.5`. So we can reuse the polynomial
evaluation of `P(u)` when `|x| < 0.5`.
For the accurate path, we redo the computations in 128-bit precision
with degree-15 (minimax + Taylor) polynomials to approximate `P(u)`.
