[libcxx-commits] [libcxx] [libc++] Extend is_trivially_equality_comparable to integral types with the same signdness and size (PR #70344)

[via libcxx-commits]

https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/70344

None

>From c63e76b882712797d16d8b116558f3e67b66f2f3 Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Thu, 26 Oct 2023 12:14:11 +0200
Subject: [PATCH] [libc++] Extend is_trivially_equality_comparable to integral
 types with the same signdness and size

---
 libcxx/include/__type_traits/is_equality_comparable.h | 11 ++++++++++-
 .../is_trivially_comparable.compile.pass.cpp          |  8 ++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/libcxx/include/__type_traits/is_equality_comparable.h b/libcxx/include/__type_traits/is_equality_comparable.h
index e8d3ce87961f148..00316ed637782d3 100644
--- a/libcxx/include/__type_traits/is_equality_comparable.h
+++ b/libcxx/include/__type_traits/is_equality_comparable.h
@@ -10,9 +10,11 @@
 #define _LIBCPP___TYPE_TRAITS_IS_EQUALITY_COMPARABLE_H
 
 #include <__config>
+#include <__type_traits/enable_if.h>
 #include <__type_traits/integral_constant.h>
 #include <__type_traits/is_integral.h>
 #include <__type_traits/is_same.h>
+#include <__type_traits/is_signed.h>
 #include <__type_traits/is_void.h>
 #include <__type_traits/remove_cv.h>
 #include <__type_traits/remove_cvref.h>
@@ -44,7 +46,7 @@ struct __is_equality_comparable<_Tp, _Up, __void_t<decltype(std::declval<_Tp>()
 //   but don't have the same bit-pattern. An exception to this is comparing to a void-pointer. There the bit-pattern is
 //   always compared.
 
-template <class _Tp, class _Up>
+template <class _Tp, class _Up, class = void>
 struct __libcpp_is_trivially_equality_comparable_impl : false_type {};
 
 template <class _Tp>
@@ -57,6 +59,13 @@ struct __libcpp_is_trivially_equality_comparable_impl<_Tp, _Tp>
 };
 #endif // __has_builtin(__is_trivially_equality_comparable)
 
+template <class _Tp, class _Up>
+struct __libcpp_is_trivially_equality_comparable_impl<
+    _Tp,
+    _Up,
+    __enable_if_t<is_integral<_Tp>::value && is_integral<_Up>::value && !is_same<_Tp, _Up>::value &&
+                  is_signed<_Tp>::value == is_signed<_Up>::value && sizeof(_Tp) == sizeof(_Up)> > : true_type {};
+
 template <class _Tp>
 struct __libcpp_is_trivially_equality_comparable_impl<_Tp*, _Tp*> : true_type {};
 
diff --git a/libcxx/test/libcxx/type_traits/is_trivially_comparable.compile.pass.cpp b/libcxx/test/libcxx/type_traits/is_trivially_comparable.compile.pass.cpp
index 3471415f4431166..6875998dc021d41 100644
--- a/libcxx/test/libcxx/type_traits/is_trivially_comparable.compile.pass.cpp
+++ b/libcxx/test/libcxx/type_traits/is_trivially_comparable.compile.pass.cpp
@@ -6,7 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include <__type_traits/conditional.h>
 #include <__type_traits/is_equality_comparable.h>
+#include <__type_traits/is_signed.h>
 
 enum Enum : int {};
 enum class EnumClass : int {};
@@ -38,6 +40,12 @@ static_assert(!std::__libcpp_is_trivially_equality_comparable<float, float>::val
 static_assert(!std::__libcpp_is_trivially_equality_comparable<double, double>::value, "");
 static_assert(!std::__libcpp_is_trivially_equality_comparable<long double, long double>::value, "");
 
+static_assert(std::__libcpp_is_trivially_equality_comparable<
+                  char,
+                  typename std::conditional<std::is_signed<char>::value, signed char, unsigned char>::type>::value,
+              "");
+static_assert(std::__libcpp_is_trivially_equality_comparable<char16_t, unsigned short>::value, "");
+
 struct S {
   char c;
 };