d883a4ad02
Implement sinf function that is correctly rounded to all rounding modes.
- We use a simple range reduction for `pi/16 < |x|` :
Let `k = round(x / pi)` and `y = (x/pi) - k`.
So `k` is an integer and `-0.5 <= y <= 0.5`.
Then
```
sin(x) = sin(y*pi + k*pi)
= (-1)^(k & 1) * sin(y*pi)
~ (-1)^(k & 1) * y * P(y^2)
```
where `y*P(y^2)` is a degree-15 minimax polynomial generated by Sollya with:
```
> P = fpminimax(sin(x*pi)/x, [|0, 2, 4, 6, 8, 10, 12, 14|], [|D...|], [0, 0.5]);
```
- Performance benchmark using perf tool from CORE-MATH project
(https://gitlab.inria.fr/core-math/core-math/-/tree/master) on Ryzen 1700:
Before this patch (not correctly rounded):
```
$ CORE_MATH_PERF_MODE="rdtsc" ./perf.sh sinf
CORE-MATH reciprocal throughput : 17.892
System LIBC reciprocal throughput : 25.559
LIBC reciprocal throughput : 29.381
```
After this patch (correctly rounded):
```
$ CORE_MATH_PERF_MODE="rdtsc" ./perf.sh sinf
CORE-MATH reciprocal throughput : 17.896
System LIBC reciprocal throughput : 25.740
LIBC reciprocal throughput : 27.872
LIBC reciprocal throughput : 20.012 (with `-msse4.2` flag)
LIBC reciprocal throughput : 14.244 (with `-mfma` flag)
```
Reviewed By: zimmermann6
Differential Revision: https://reviews.llvm.org/D123154
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| .. | ||
| api_test.rst | ||
| build_system.rst | ||
| clang_tidy_checks.rst | ||
| CMakeLists.txt | ||
| conf.py | ||
| entrypoints.rst | ||
| fuzzing.rst | ||
| ground_truth_specification.rst | ||
| header_gen_scheme.svg | ||
| header_generation.rst | ||
| implementation_standard.rst | ||
| index.rst | ||
| layering.rst | ||
| math.rst | ||
| mechanics_of_public_api.rst | ||
| README.txt | ||
| redirectors.rst | ||
| redirectors_schematic.svg | ||
| runtimes_build.rst | ||
| source_layout.rst | ||
| stdio.rst | ||
| strings.rst | ||
libc Documentation ================== The libc documentation is written using the Sphinx documentation generator. It is currently tested with Sphinx 1.1.3. To build the documents into html configure libc with the following cmake options: * -DLLVM_ENABLE_SPHINX=ON * -DLIBC_INCLUDE_DOCS=ON After configuring libc with these options the make rule `docs-libc-html` should be available.