[libcxx-commits] [libcxx] [libc++][math] Add `constexpr` to `copysign` functions (PR #216285)

[Nikolas Klauser via libcxx-commits]

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@@ -24,19 +24,33 @@ namespace __math {
 
 // copysign
 
-[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI float copysign(float __x, float __y) _NOEXCEPT {
+[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI float
+copysign(float __x, float __y) _NOEXCEPT {
   return ::__builtin_copysignf(__x, __y);
 }
 
-[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI long double copysign(long double __x, long double __y) _NOEXCEPT {
+[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI long double
+copysign(long double __x, long double __y) _NOEXCEPT {
   return ::__builtin_copysignl(__x, __y);
 }
 
 template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
-[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI __promote_t<_A1, _A2> copysign(_A1 __x, _A2 __y) _NOEXCEPT {
+[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI __promote_t<_A1, _A2>
+copysign(_A1 __x, _A2 __y) _NOEXCEPT {
   return ::__builtin_copysign(__x, __y);
 }
 
+#ifdef _LIBCPP_PREFERRED_OVERLOAD
+[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_PREFERRED_OVERLOAD float copysignf(float __x, float __y) _NOEXCEPT {
+  return __builtin_copysignf(__x, __y);
+}
+[[__nodiscard__]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI _LIBCPP_PREFERRED_OVERLOAD long double
+copysignl(long double __x, long double __y) _NOEXCEPT {
+  return __builtin_copysignl(__x, __y);
+}
+#endif
+
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philnik777 wrote:

It won't. GCC doesn't have `__attribute__((enable_if))`. If it did, we wouldn't have to check whether we have it everywhere.

https://github.com/llvm/llvm-project/pull/216285