forked from OSchip/llvm-project
6168b42225
Reduce the polynomial's degree from 7 down to 4. Currently we use a degree-7 minimax polynomial on an interval of length 2^-7 around 0 to compute `expf`. Based on the suggestion of @santoshn and the RLIBM project (https://github.com/rutgers-apl/rlibm-all/blob/main/source/float/exp.c) and the improvement we made with `exp2f` in https://reviews.llvm.org/D122346, it is possible to have a good polynomial of degree-4 on a subinterval of length 2^(-7) to approximate e^x. We did try to either reduce the degree of the polynomial down to 3 or increase the interval size to 2^(-6), but in both cases the number of exceptional values exploded. So we settle with using a degree-4 polynomial of the interval of size 2^(-7) around 0. Reviewed By: sivachandra, zimmermann6, santoshn Differential Revision: https://reviews.llvm.org/D122418 |
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| __support | ||
| assert | ||
| ctype | ||
| errno | ||
| fcntl | ||
| fenv | ||
| inttypes | ||
| math | ||
| signal | ||
| stdio | ||
| stdlib | ||
| string | ||
| sys | ||
| threads | ||
| time | ||
| unistd | ||
| .clang-tidy | ||
| CMakeLists.txt | ||