__to_chars_10_impl is quite fast. According to the IACA the main loop
takes only 6.0 cycles, the whole function with one iteration takes
10.0 cycles. Replacing the __first[pos] and __first[pos - 1] with
__first[0] and __first[1] drops the function time to 7.53 cycles.
2019-09-09 Antony Polukhin <antoshkka@gmail.com>
* include/bits/charconv.h (__detail::__to_chars_10_impl): Replace
final offsets with constants.
From-SVN: r275514
d0e086ae4f