coffee/fast_float
1
0
Fork 0
mirror of https://github.com/fastfloat/fast_float.git synced 2026-11-09 14:49:59 +08:00
Code Issues Packages Projects Releases Wiki Activity

FASTFLOAT_ASSUME and Clang related crutches cleanup.

Browse Source
This commit is contained in:
HedgehogInTheCPP 2026-08-22 22:14:00 +03:00
parent bc1316970c
commit 207069edcd
4 changed files with 51 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
include/fast_float/bigint.h
View File

@ -618,11 +618,20 @@ struct bigint : pow5_tables<> {
exp -= small_step;
}
if (exp != 0) {
// Work around clang bug https://godbolt.org/z/zedh7rrhc
// This is similar to https://github.com/llvm/llvm-project/issues/47746,
// except the workaround described there don't work here
FASTFLOAT_TRY(small_mul(vec, limb((static_cast<void>(small_power_of_5[0]),
small_power_of_5[exp]))));
FASTFLOAT_TRY(small_mul(
vec,
limb(
#if defined(__clang__)
// Work around clang bug https://godbolt.org/z/zedh7rrhc
// This is similar to
// https://github.com/llvm/llvm-project/issues/47746, except
// the workaround described there don't work here
(static_cast<void>(small_power_of_5[0]), small_power_of_5[exp])
#else
small_power_of_5[exp]
#endif
)));
}
return true;

20
include/fast_float/constexpr_feature_detect.h
View File

@ -54,7 +54,7 @@
#define FASTFLOAT_INLINE_VARIABLE static constexpr
#endif
// Before C++17, constexpr variables may need an out-of-class definition.
// Before C++17 constexpr variables may need an out-of-class definition.
#if __cplusplus >= 201703L || (defined(_MSC_VER) && _MSVC_LANG >= 201703L)
#define FASTFLOAT_DETAIL_MUST_DEFINE_CONSTEXPR_VARIABLE 0
#else
@ -98,13 +98,15 @@
#define FASTFLOAT_HAS_BUILTIN(x) false
#endif
#if defined(FASTFLOAT_ASSUME)
// user provided solution
#elif defined(__cpp_attrubute_assume)
// For support attribute [[assume]] is declared in P1774
#define FASTFLOAT_ASSUME(expr) [[assume(expr)]]
#else
#define FASTFLOAT_ASSUME(expr)
#endif
// #if defined(FASTFLOAT_ASSUME)
// user provided solution
// #elif defined(__cpp_attrubute_assume)
// For support attribute [[assume]] is declared in P1774
#define FASTFLOAT_ASSUME(expr) \
assert(expr); \
[[assume(expr)]]
// #else
// #define FASTFLOAT_ASSUME(expr)
// #endif
#endif // FASTFLOAT_CONSTEXPR_FEATURE_DETECT_H

30
include/fast_float/float_common.h
View File

@ -944,8 +944,12 @@ constexpr uint16_t
template <>
inline constexpr std::float16_t
binary_format<std::float16_t>::exact_power_of_ten(am_pow_t power) {
#if defined(__clang__)
// Work around clang bug https://godbolt.org/z/zedh7rrhc
return (void)powers_of_ten[0], powers_of_ten[power];
return (void)max_mantissa[0], max_mantissa[power];
#else
return max_mantissa[power];
#endif
}
template <>
@ -989,9 +993,12 @@ inline constexpr am_mant_t
binary_format<std::float16_t>::max_mantissa_fast_path(am_pow_t power) {
// caller is responsible to ensure that
FASTFLOAT_ASSUME(power >= 0 && power <= 4);
//
#if defined(__clang__)
// Work around clang bug https://godbolt.org/z/zedh7rrhc
return (void)max_mantissa[0], max_mantissa[power];
#else
return max_mantissa[power];
#endif
}
template <>
@ -1077,8 +1084,12 @@ constexpr uint16_t
template <>
inline constexpr std::bfloat16_t
binary_format<std::bfloat16_t>::exact_power_of_ten(am_pow_t power) {
#if defined(__clang__)
// Work around clang bug https://godbolt.org/z/zedh7rrhc
return (void)powers_of_ten[0], powers_of_ten[power];
return (void)max_mantissa[0], max_mantissa[power];
#else
return max_mantissa[power];
#endif
}
template <>
@ -1122,9 +1133,12 @@ inline constexpr am_mant_t
binary_format<std::bfloat16_t>::max_mantissa_fast_path(am_pow_t power) {
// caller is responsible to ensure that
FASTFLOAT_ASSUME(power >= 0 && power <= 3);
//
#if defined(__clang__)
// Work around clang bug https://godbolt.org/z/zedh7rrhc
return (void)max_mantissa[0], max_mantissa[power];
#else
return max_mantissa[power];
#endif
}
template <>
@ -1186,7 +1200,7 @@ template <>
inline constexpr am_mant_t
binary_format<double>::max_mantissa_fast_path(am_pow_t power) {
// caller is responsible to ensure that
// FASTFLOAT_ASSUME(power >= 0 && power <= 22);
FASTFLOAT_ASSUME(power >= 0 && power <= 22);
#if defined(__clang__)
// Work around clang bug https://godbolt.org/z/zedh7rrhc
return (void)max_mantissa[0], max_mantissa[power];
@ -1199,7 +1213,7 @@ template <>
inline constexpr am_mant_t
binary_format<float>::max_mantissa_fast_path(am_pow_t power) {
// caller is responsible to ensure that
// FASTFLOAT_ASSUME(power >= 0 && power <= 10);
FASTFLOAT_ASSUME(power >= 0 && power <= 10);
#if defined(__clang__)
// Work around clang bug https://godbolt.org/z/zedh7rrhc
return (void)max_mantissa[0], max_mantissa[power];
@ -1212,7 +1226,7 @@ template <>
inline constexpr double
binary_format<double>::exact_power_of_ten(am_pow_t power) {
// caller is responsible to ensure that
// FASTFLOAT_ASSUME(power >= 0 && power <= 22);
FASTFLOAT_ASSUME(power >= 0 && power <= 22);
#if defined(__clang__)
// Work around clang bug https://godbolt.org/z/zedh7rrhc
return (void)powers_of_ten[0], powers_of_ten[power];
@ -1225,7 +1239,7 @@ template <>
inline constexpr float
binary_format<float>::exact_power_of_ten(am_pow_t power) {
// caller is responsible to ensure that
// FASTFLOAT_ASSUME(power >= 0 && power <= 10);
FASTFLOAT_ASSUME(power >= 0 && power <= 10);
#if defined(__clang__)
// Work around clang bug https://godbolt.org/z/zedh7rrhc
return (void)powers_of_ten[0], powers_of_ten[power];

6
include/fast_float/parse_number.h
View File

@ -218,9 +218,11 @@ clinger_fast_path_impl(am_mant_t const mantissa, am_pow_t const exponent,
// We could check it first (before the previous branch), but
// there might be performance advantages at having the check
// be last.
if (!is_constant_evaluated()
#ifndef FASTFLOAT_ONLY_ROUNDS_TO_NEAREST_SUPPORTED
if (detail::rounds_to_nearest()) {
&& detail::rounds_to_nearest()
#endif
) {
// We have that fegetround() == FE_TONEAREST.
// Next is Clinger's fast path.
if (mantissa <= binary_format<T>::max_mantissa_fast_path()) {
@ -263,8 +265,8 @@ clinger_fast_path_impl(am_mant_t const mantissa, am_pow_t const exponent,
}
#endif
return true;
}
#endif
}
}
}
return false;