[libc][docs] Add GPU math conformance test results to support page

[leandrolcampos]

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.

[llvmbot]

@llvm/pr-subscribers-libc

Author: Leandro Lacerda (leandrolcampos)

Changes

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.

---

Patch is 22.44 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/156263.diff

1 Files Affected:

• (modified) libc/docs/gpu/support.rst (+166)

diff --git a/libc/docs/gpu/support.rst b/libc/docs/gpu/support.rst
index 3fb2df8e6f2ca..4243900fb81d4 100644
--- a/libc/docs/gpu/support.rst
+++ b/libc/docs/gpu/support.rst
@@ -281,3 +281,169 @@ Function Name  Available  RPC Required
 assert         |check|    |check|
 __assert_fail  |check|    |check|
 =============  =========  ============
+
+math.h
+------
+
+The following table presents the conformance test results for higher math functions on the GPU. The results show the maximum observed ULP (Units in the Last Place) distance when comparing the GPU implementation against a correctly rounded reference computed on the host CPU. In addition to the C standard math library (LLVM-libm), these tests are conducted against CUDA Math and HIP Math, for comparison only.
+
++------------------------+-------------+---------------+-----------------------------------------------------------------------------------+
+| Function               | Test Method | ULP Tolerance | Max ULP Distance                                                                  |
+|                        |             |               +--------------------+--------------------+--------------------+--------------------+
+|                        |             |               | llvm-libm          | llvm-libm          | cuda-math          | hip-math           |
+|                        |             |               | (AMDGPU)           | (CUDA)             | (CUDA)             | (AMDGPU)           |
++========================+=============+===============+====================+====================+====================+====================+
+| acos                   | Randomized  | 4             | 6 (FAILED)         | 6 (FAILED)         | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| acosf                  | Exhaustive  | 4             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| acosf16                | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| acoshf                 | Exhaustive  | 4             | 1                  | 1                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| acoshf16               | Exhaustive  | 2             | 0                  | 0                  |                    | 0                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| acospif16              | Exhaustive  | 2             | 0                  | 0                  |                    |                    |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| asin                   | Randomized  | 4             | 6 (FAILED)         | 6 (FAILED)         | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| asinf                  | Exhaustive  | 4             | 1                  | 1                  | 1                  | 3                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| asinf16                | Exhaustive  | 2             | 0                  | 0                  |                    | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| asinhf                 | Exhaustive  | 4             | 1                  | 1                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| asinhf16               | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| atanf                  | Exhaustive  | 5             | 0                  | 0                  | 1                  | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| atanf16                | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| atan2f                 | Randomized  | 6             | 1                  | 1                  | 2                  | 3                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| atanhf                 | Exhaustive  | 5             | 0                  | 0                  | 3                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| atanhf16               | Exhaustive  | 2             | 0                  | 0                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| cbrt                   | Randomized  | 2             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| cbrtf                  | Exhaustive  | 2             | 0                  | 0                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| cos                    | Randomized  | 4             | 1                  | 1                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| cosf                   | Exhaustive  | 4             | 1                  | 1                  | 2                  | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| cosf16                 | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| coshf                  | Exhaustive  | 4             | 0                  | 0                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| coshf16                | Exhaustive  | 2             | 1                  | 0                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| cospif                 | Exhaustive  | 4             | 0                  | 0                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| cospif16               | Exhaustive  | 2             | 0                  | 0                  |                    |                    |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| erff                   | Exhaustive  | 16            | 0                  | 0                  | 1                  | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| exp                    | Randomized  | 3             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| expf                   | Exhaustive  | 3             | 0                  | 0                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| expf16                 | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| exp10                  | Randomized  | 3             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| exp10f                 | Exhaustive  | 3             | 0                  | 0                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| exp10f16               | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| exp2                   | Randomized  | 3             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| exp2f                  | Exhaustive  | 3             | 1                  | 1                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| exp2f16                | Exhaustive  | 2             | 1                  | 1                  |                    | 0                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| expm1                  | Randomized  | 3             | 0                  | 0                  | 1                  | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| expm1f                 | Exhaustive  | 3             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| expm1f16               | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| hypot                  | Randomized  | 4             | 0                  | 0                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| hypotf                 | Randomized  | 4             | 0                  | 0                  | 1                  | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| hypotf16               | Exhaustive  | 2             | 0                  | 0                  |                    |                    |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| log                    | Randomized  | 3             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| logf                   | Exhaustive  | 3             | 1                  | 1                  | 1                  | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| logf16                 | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| log10                  | Randomized  | 3             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| log10f                 | Exhaustive  | 3             | 1                  | 1                  | 2                  | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| log10f16               | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| log1p                  | Randomized  | 2             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| log1pf                 | Exhaustive  | 2             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| log2                   | Randomized  | 3             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| log2f                  | Exhaustive  | 3             | 0                  | 0                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| log2f16                | Exhaustive  | 2             | 1                  | 1                  |                    | 0                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| powf (integer exp.)    | Randomized  | 16            | 0                  | 0                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| powf (real exp.)       | Randomized  | 16            | 0                  | 0                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sin                    | Randomized  | 4             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sinf                   | Exhaustive  | 4             | 1                  | 1                  | 1                  | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sinf16                 | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sincos (cos part)      | Randomized  | 4             | 1                  | 1                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sincos (sin part)      | Randomized  | 4             | 1                  | 1                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sincosf (cos part)     | Exhaustive  | 4             | 1                  | 1                  | 2                  | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sincosf (sin part)     | Exhaustive  | 4             | 1                  | 1                  | 1                  | 2                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sinhf                  | Exhaustive  | 4             | 1                  | 1                  | 3                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sinhf16                | Exhaustive  | 2             | 1                  | 1                  |                    | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sinpif                 | Exhaustive  | 4             | 0                  | 0                  | 1                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| sinpif16               | Exhaustive  | 2             | 0                  | 0                  |                    |                    |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| tan                    | Randomized  | 5             | 2                  | 2                  | 2                  | 1                  |
++------------------------+-------------+---------------+--------------------+--------------------+--------------------+--------------------+
+| tanf                   | Exhaustive  | 5             | 0                  | 0                  | 3      ...
[truncated]

[jhuber6]

The support is just for functions that you can call, we'd want a new directory for these types of results similar to the ones listed for the CPU.

[leandrolcampos]

The support is just for functions that you can call, we'd want a new directory for these types of results similar to the ones listed for the CPU.

I followed this suggestion from @lntue.

[lntue]

The list of math functions will be quite big later, so probably they could be in a separate page to make other headers accessible. Also include the config that the GPU math functions are built with.