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exclude fallback functions when FMT_BUILTIN_CLZ(LL) is not defined

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Signed-off-by: Bodo Martin <bodo.martin@aci.uni-heidelberg.de>
This commit is contained in:
Bodo Martin 2021-07-25 13:30:04 +02:00
parent 5c222f0561
commit 901d2a75cc
1 changed files with 4 additions and 0 deletions
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4
include/fmt/format.h
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@ -918,6 +918,7 @@ FMT_CONSTEXPR inline auto count_digits(uint128_t n) -> int {
// It is a separate function rather than a part of count_digits to workaround
// the lack of static constexpr in constexpr functions.
#ifdef FMT_BUILTIN_CLZLL
inline auto do_count_digits(uint64_t n) -> int {
// This has comparable performance to the version by Kendall Willets
// (https://github.com/fmtlib/format-benchmark/blob/master/digits10)
@ -934,6 +935,7 @@ inline auto do_count_digits(uint64_t n) -> int {
10000000000000000000ULL};
return t - (n < zero_or_powers_of_10[t]);
}
#endif
// Returns the number of decimal digits in n. Leading zeros are not counted
// except for n == 0 in which case count_digits returns 1.
@ -964,6 +966,7 @@ template <> auto count_digits<4>(detail::fallback_uintptr n) -> int;
// It is a separate function rather than a part of count_digits to workaround
// the lack of static constexpr in constexpr functions.
#ifdef FMT_BUILTIN_CLZ
FMT_INLINE auto do_count_digits(uint32_t n) -> int {
// An optimization by Kendall Willets from https://bit.ly/3uOIQrB.
// This increments the upper 32 bits (log10(T) - 1) when >= T is added.
@ -984,6 +987,7 @@ FMT_INLINE auto do_count_digits(uint32_t n) -> int {
auto inc = table[FMT_BUILTIN_CLZ(n | 1) ^ 31];
return static_cast<int>((n + inc) >> 32);
}
#endif
// Optional version of count_digits for better performance on 32-bit platforms.
FMT_CONSTEXPR20 inline auto count_digits(uint32_t n) -> int {