[libcxx-commits] [libcxx] [libc++] Remove one of the std::signbit overloads (PR #130505)

[Nikolas Klauser via libcxx-commits]

https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/130505

We'e specialized `std::signbit` for signed and unsigned integral types seperately, even though the optimizer can trivially figure out that `unsigned_value < 0` always false is. This patch removes the specialization, since there is really not much of a benefit to it.



>From dd883fb60a9cc1b2d86a9a86447d1cb1696ebfda Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Sun, 9 Mar 2025 20:10:37 +0100
Subject: [PATCH] [libc++] Remove one of the std::signbit overloads

---
 libcxx/include/__math/traits.h | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/libcxx/include/__math/traits.h b/libcxx/include/__math/traits.h
index 0c96f766a767e..550eb393e2d4f 100644
--- a/libcxx/include/__math/traits.h
+++ b/libcxx/include/__math/traits.h
@@ -13,7 +13,6 @@
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_arithmetic.h>
 #include <__type_traits/is_integral.h>
-#include <__type_traits/is_signed.h>
 #include <__type_traits/promote.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -51,16 +50,11 @@ template <class = void>
   return __builtin_signbit(__x);
 }
 
-template <class _A1, __enable_if_t<is_integral<_A1>::value && is_signed<_A1>::value, int> = 0>
+template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
 [[__nodiscard__]] inline _LIBCPP_SIGNBIT_CONSTEXPR _LIBCPP_HIDE_FROM_ABI bool signbit(_A1 __x) _NOEXCEPT {
   return __x < 0;
 }
 
-template <class _A1, __enable_if_t<is_integral<_A1>::value && !is_signed<_A1>::value, int> = 0>
-[[__nodiscard__]] inline _LIBCPP_SIGNBIT_CONSTEXPR _LIBCPP_HIDE_FROM_ABI bool signbit(_A1) _NOEXCEPT {
-  return false;
-}
-
 // isfinite
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>