Implement double precision log10 function correctly rounded for all
rounding modes. This implementation currently needs FMA instructions for
Use 2 passes:
- 1 step range reduction with a lookup table of 2^7 = 128 elements to reduce the ranges to [-2^-7, 2^-7].
- Use a degree-7 minimax polynomial generated by Sollya, evaluated using a mixed of double-double and double precisions.
- Apply Ziv's test for accuracy.
- Apply 5 more range reduction steps to reduce the ranges further to [-2^-27, 2^-27].
- Use a degree-4 minimax polynomial generated by Sollya, evaluated using 192-bit precisions.
- By the result of Lefevre (add quote), this is more than enough for correct rounding to all rounding modes.
In progress: Adding detail documentations about the algorithm.
Depend on: https://reviews.llvm.org/D136799