llvm-project.git/libc/test/src/math/smoke/sin_test.cpp, branch main Unnamed repository; edit this file 'description' to name the repository. [libc][math] Fix signaling NaN handling for math functions. (#133347) 2025-04-08T13:23:38+00:00 wldfngrs wldfngrs@gmail.com 2025-04-08T13:23:38+00:00 fdf20941a8f95b26578fbeb579019f74efe45545 Add tests for signaling NaNs, and fix function behavior for handling signaling NaN input. Fixes https://github.com/llvm/llvm-project/issues/124812 
Add tests for signaling NaNs, and fix function behavior for handling
signaling NaN input.

Fixes https://github.com/llvm/llvm-project/issues/124812
 [libc][math] Add tests and fix some issues with FTZ/DAZ modes. (#113744) 2024-10-26T14:55:20+00:00 lntue lntue@google.com 2024-10-26T14:55:20+00:00 0f4b3c409fbd756d826c89d5539d9ea22bcc56aa 






[libc][math] Implement double precision sin correctly rounded to all rounding modes. (#95736)
2024-06-24T21:57:08+00:00

lntue
35648136+lntue@users.noreply.github.com

2024-06-24T21:57:08+00:00

16903ace180755b7558234ff2b2e8d89b00dcb88

- Algorithm:
- Step 1 - Range reduction: for a double precision input `x`, return `k`
and `u` such that
    - k is an integer
    - u = x - k * pi / 128, and |u| < pi/256
- Step 2 - Calculate `sin(u)` and `cos(u)` in double-double using Taylor
polynomials with errors < 2^-70 with FMA or < 2^-66 w/o FMA.
- Step 3 - Calculate `sin(x) = sin(k*pi/128) * cos(u) + cos(k*pi/128) *
sin(u)` using look-up table for `sin(k*pi/128)` and `cos(k*pi/128)`.
- Step 4 - Use Ziv's rounding test to decide if the result is correctly
rounded.
- Step 4' - If the Ziv's rounding test failed, redo step 1-3 using
128-bit precision.
- Currently, without FMA instructions, the large range reduction only
works correctly for the default rounding mode (FE_TONEAREST).
- Provide `LIBC_MATH` flag so that users can set `LIBC_MATH =
LIBC_MATH_SKIP_ACCURATE_PASS` to build the `sin` function without step 4
and 4'.




- Algorithm:
- Step 1 - Range reduction: for a double precision input `x`, return `k`
and `u` such that
    - k is an integer
    - u = x - k * pi / 128, and |u| < pi/256
- Step 2 - Calculate `sin(u)` and `cos(u)` in double-double using Taylor
polynomials with errors < 2^-70 with FMA or < 2^-66 w/o FMA.
- Step 3 - Calculate `sin(x) = sin(k*pi/128) * cos(u) + cos(k*pi/128) *
sin(u)` using look-up table for `sin(k*pi/128)` and `cos(k*pi/128)`.
- Step 4 - Use Ziv's rounding test to decide if the result is correctly
rounded.
- Step 4' - If the Ziv's rounding test failed, redo step 1-3 using
128-bit precision.
- Currently, without FMA instructions, the large range reduction only
works correctly for the default rounding mode (FE_TONEAREST).
- Provide `LIBC_MATH` flag so that users can set `LIBC_MATH =
LIBC_MATH_SKIP_ACCURATE_PASS` to build the `sin` function without step 4
and 4'.