[libcxx-commits] [libcxx] [libc++] Refactor signed/unsigned integer traits (PR #142750)

Fri Jun 6 00:01:11 PDT 2025

llvmbot wrote:




@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

<details>
<summary>Changes</summary>

This patch does a few things:
- `__libcpp_is_signed_integer` and `__libcpp_is_unsigned_integer` are refactored to be variable templates instead of class templates.
- the two traits are merged into a single header `<__type_traits/integer_traits.h>`.
- `__libcpp_signed_integer`, `__libcpp_unsigned_integer` and `__libcpp_integer` are moved into the same header.
- The above mentioned concepts are renamed to `__signed_integer`, `__unsigned_integer` and `__signed_or_unsigned_integer` respectively.


---

Patch is 41.28 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/142750.diff


22 Files Affected:

- (modified) libcxx/include/CMakeLists.txt (+1-2) 
- (modified) libcxx/include/__bit/bit_ceil.h (+2-2) 
- (modified) libcxx/include/__bit/bit_floor.h (+2-2) 
- (modified) libcxx/include/__bit/bit_log2.h (+2-2) 
- (modified) libcxx/include/__bit/bit_width.h (+2-2) 
- (modified) libcxx/include/__bit/countl.h (+4-5) 
- (modified) libcxx/include/__bit/countr.h (+4-5) 
- (modified) libcxx/include/__bit/has_single_bit.h (+2-2) 
- (modified) libcxx/include/__bit/popcount.h (+3-4) 
- (modified) libcxx/include/__bit/rotate.h (+5-6) 
- (modified) libcxx/include/__concepts/arithmetic.h (-13) 
- (modified) libcxx/include/__format/format_arg_store.h (+3-3) 
- (modified) libcxx/include/__mdspan/extents.h (+3-3) 
- (modified) libcxx/include/__numeric/saturation_arithmetic.h (+15-15) 
- (added) libcxx/include/__type_traits/integer_traits.h (+73) 
- (removed) libcxx/include/__type_traits/is_signed_integer.h (-35) 
- (removed) libcxx/include/__type_traits/is_unsigned_integer.h (-35) 
- (modified) libcxx/include/__utility/cmp.h (+8-8) 
- (modified) libcxx/include/module.modulemap.in (+1-8) 
- (modified) libcxx/test/libcxx/concepts/concepts.arithmetic/__libcpp_integer.compile.pass.cpp (+31-31) 
- (modified) libcxx/test/libcxx/concepts/concepts.arithmetic/__libcpp_signed_integer.compile.pass.cpp (+31-31) 
- (modified) libcxx/test/libcxx/concepts/concepts.arithmetic/__libcpp_unsigned_integer.compile.pass.cpp (+31-31) 


``````````diff

diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 43cefd5600646..ed6cb6d88dfa0 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -800,6 +800,7 @@ set(files
   __type_traits/extent.h
   __type_traits/has_unique_object_representation.h
   __type_traits/has_virtual_destructor.h
+  __type_traits/integer_traits.h
   __type_traits/integral_constant.h
   __type_traits/invoke.h
   __type_traits/is_abstract.h
@@ -850,7 +851,6 @@ set(files
   __type_traits/is_same.h
   __type_traits/is_scalar.h
   __type_traits/is_signed.h
-  __type_traits/is_signed_integer.h
   __type_traits/is_specialization.h
   __type_traits/is_standard_layout.h
   __type_traits/is_swappable.h
@@ -864,7 +864,6 @@ set(files
   __type_traits/is_unbounded_array.h
   __type_traits/is_union.h
   __type_traits/is_unsigned.h
-  __type_traits/is_unsigned_integer.h
   __type_traits/is_valid_expansion.h
   __type_traits/is_void.h
   __type_traits/is_volatile.h
diff --git a/libcxx/include/__bit/bit_ceil.h b/libcxx/include/__bit/bit_ceil.h
index cfd792dc2e2ad..99881a8538290 100644
--- a/libcxx/include/__bit/bit_ceil.h
+++ b/libcxx/include/__bit/bit_ceil.h
@@ -11,8 +11,8 @@
 
 #include <__assert>
 #include <__bit/countl.h>
-#include <__concepts/arithmetic.h>
 #include <__config>
+#include <__type_traits/integer_traits.h>
 #include <limits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -41,7 +41,7 @@ template <class _Tp>
 
 #  if _LIBCPP_STD_VER >= 20
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp bit_ceil(_Tp __t) noexcept {
   return std::__bit_ceil(__t);
 }
diff --git a/libcxx/include/__bit/bit_floor.h b/libcxx/include/__bit/bit_floor.h
index 6bcbc53fb4972..799a064130b4b 100644
--- a/libcxx/include/__bit/bit_floor.h
+++ b/libcxx/include/__bit/bit_floor.h
@@ -10,8 +10,8 @@
 #define _LIBCPP___BIT_BIT_FLOOR_H
 
 #include <__bit/bit_log2.h>
-#include <__concepts/arithmetic.h>
 #include <__config>
+#include <__type_traits/integer_traits.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,7 +21,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 20
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp bit_floor(_Tp __t) noexcept {
   return __t == 0 ? 0 : _Tp{1} << std::__bit_log2(__t);
 }
diff --git a/libcxx/include/__bit/bit_log2.h b/libcxx/include/__bit/bit_log2.h
index b22e1ce1f84e6..8077cd91d6fd7 100644
--- a/libcxx/include/__bit/bit_log2.h
+++ b/libcxx/include/__bit/bit_log2.h
@@ -11,7 +11,7 @@
 
 #include <__bit/countl.h>
 #include <__config>
-#include <__type_traits/is_unsigned_integer.h>
+#include <__type_traits/integer_traits.h>
 #include <limits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -22,7 +22,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp __bit_log2(_Tp __t) _NOEXCEPT {
-  static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__bit_log2 requires an unsigned integer type");
+  static_assert(__is_unsigned_integer_v<_Tp>, "__bit_log2 requires an unsigned integer type");
   return numeric_limits<_Tp>::digits - 1 - std::__countl_zero(__t);
 }
 
diff --git a/libcxx/include/__bit/bit_width.h b/libcxx/include/__bit/bit_width.h
index 853e481776f7d..75050acabbe88 100644
--- a/libcxx/include/__bit/bit_width.h
+++ b/libcxx/include/__bit/bit_width.h
@@ -10,8 +10,8 @@
 #define _LIBCPP___BIT_BIT_WIDTH_H
 
 #include <__bit/bit_log2.h>
-#include <__concepts/arithmetic.h>
 #include <__config>
+#include <__type_traits/integer_traits.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,7 +21,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int bit_width(_Tp __t) noexcept {
   return __t == 0 ? 0 : std::__bit_log2(__t) + 1;
 }
diff --git a/libcxx/include/__bit/countl.h b/libcxx/include/__bit/countl.h
index 9499bf9b458ee..075914020879a 100644
--- a/libcxx/include/__bit/countl.h
+++ b/libcxx/include/__bit/countl.h
@@ -9,9 +9,8 @@
 #ifndef _LIBCPP___BIT_COUNTL_H
 #define _LIBCPP___BIT_COUNTL_H
 
-#include <__concepts/arithmetic.h>
 #include <__config>
-#include <__type_traits/is_unsigned_integer.h>
+#include <__type_traits/integer_traits.h>
 #include <limits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -25,18 +24,18 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int __countl_zero(_Tp __t) _NOEXCEPT {
-  static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countl_zero requires an unsigned integer type");
+  static_assert(__is_unsigned_integer_v<_Tp>, "__countl_zero requires an unsigned integer type");
   return __builtin_clzg(__t, numeric_limits<_Tp>::digits);
 }
 
 #if _LIBCPP_STD_VER >= 20
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int countl_zero(_Tp __t) noexcept {
   return std::__countl_zero(__t);
 }
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int countl_one(_Tp __t) noexcept {
   return __t != numeric_limits<_Tp>::max() ? std::countl_zero(static_cast<_Tp>(~__t)) : numeric_limits<_Tp>::digits;
 }
diff --git a/libcxx/include/__bit/countr.h b/libcxx/include/__bit/countr.h
index 7b311b83853c5..f6c98695d3d06 100644
--- a/libcxx/include/__bit/countr.h
+++ b/libcxx/include/__bit/countr.h
@@ -9,9 +9,8 @@
 #ifndef _LIBCPP___BIT_COUNTR_H
 #define _LIBCPP___BIT_COUNTR_H
 
-#include <__concepts/arithmetic.h>
 #include <__config>
-#include <__type_traits/is_unsigned.h>
+#include <__type_traits/integer_traits.h>
 #include <limits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -25,18 +24,18 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __countr_zero(_Tp __t) _NOEXCEPT {
-  static_assert(is_unsigned<_Tp>::value, "__countr_zero only works with unsigned types");
+  static_assert(__is_unsigned_integer_v<_Tp>, "__countr_zero only works with unsigned types");
   return __builtin_ctzg(__t, numeric_limits<_Tp>::digits);
 }
 
 #if _LIBCPP_STD_VER >= 20
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int countr_zero(_Tp __t) noexcept {
   return std::__countr_zero(__t);
 }
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int countr_one(_Tp __t) noexcept {
   return __t != numeric_limits<_Tp>::max() ? std::countr_zero(static_cast<_Tp>(~__t)) : numeric_limits<_Tp>::digits;
 }
diff --git a/libcxx/include/__bit/has_single_bit.h b/libcxx/include/__bit/has_single_bit.h
index 52f5853a1bc8a..b43e69323e77b 100644
--- a/libcxx/include/__bit/has_single_bit.h
+++ b/libcxx/include/__bit/has_single_bit.h
@@ -9,8 +9,8 @@
 #ifndef _LIBCPP___BIT_HAS_SINGLE_BIT_H
 #define _LIBCPP___BIT_HAS_SINGLE_BIT_H
 
-#include <__concepts/arithmetic.h>
 #include <__config>
+#include <__type_traits/integer_traits.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -23,7 +23,7 @@ _LIBCPP_PUSH_MACROS
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool has_single_bit(_Tp __t) noexcept {
   return __t != 0 && (((__t & (__t - 1)) == 0));
 }
diff --git a/libcxx/include/__bit/popcount.h b/libcxx/include/__bit/popcount.h
index 9ae572d466ba7..8d9ba09938482 100644
--- a/libcxx/include/__bit/popcount.h
+++ b/libcxx/include/__bit/popcount.h
@@ -9,9 +9,8 @@
 #ifndef _LIBCPP___BIT_POPCOUNT_H
 #define _LIBCPP___BIT_POPCOUNT_H
 
-#include <__concepts/arithmetic.h>
 #include <__config>
-#include <__type_traits/is_unsigned.h>
+#include <__type_traits/integer_traits.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -24,13 +23,13 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR int __popcount(_Tp __t) _NOEXCEPT {
-  static_assert(is_unsigned<_Tp>::value, "__popcount only works with unsigned types");
+  static_assert(__is_unsigned_integer_v<_Tp>, "__popcount only works with unsigned types");
   return __builtin_popcountg(__t);
 }
 
 #if _LIBCPP_STD_VER >= 20
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int popcount(_Tp __t) noexcept {
   return std::__popcount(__t);
 }
diff --git a/libcxx/include/__bit/rotate.h b/libcxx/include/__bit/rotate.h
index d79d98de296aa..c6f34bdaf6e63 100644
--- a/libcxx/include/__bit/rotate.h
+++ b/libcxx/include/__bit/rotate.h
@@ -9,9 +9,8 @@
 #ifndef _LIBCPP___BIT_ROTATE_H
 #define _LIBCPP___BIT_ROTATE_H
 
-#include <__concepts/arithmetic.h>
 #include <__config>
-#include <__type_traits/is_unsigned_integer.h>
+#include <__type_traits/integer_traits.h>
 #include <limits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -25,7 +24,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 // the rotr function becomes the ROR instruction.
 template <class _Tp>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp __rotl(_Tp __x, int __s) _NOEXCEPT {
-  static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotl requires an unsigned integer type");
+  static_assert(__is_unsigned_integer_v<_Tp>, "__rotl requires an unsigned integer type");
   const int __n = numeric_limits<_Tp>::digits;
   int __r       = __s % __n;
 
@@ -40,7 +39,7 @@ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp __rotl(_Tp __x, int __s)
 
 template <class _Tp>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp __rotr(_Tp __x, int __s) _NOEXCEPT {
-  static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotr requires an unsigned integer type");
+  static_assert(__is_unsigned_integer_v<_Tp>, "__rotr requires an unsigned integer type");
   const int __n = numeric_limits<_Tp>::digits;
   int __r       = __s % __n;
 
@@ -55,12 +54,12 @@ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp __rotr(_Tp __x, int __s)
 
 #if _LIBCPP_STD_VER >= 20
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotl(_Tp __t, int __cnt) noexcept {
   return std::__rotl(__t, __cnt);
 }
 
-template <__libcpp_unsigned_integer _Tp>
+template <__unsigned_integer _Tp>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotr(_Tp __t, int __cnt) noexcept {
   return std::__rotr(__t, __cnt);
 }
diff --git a/libcxx/include/__concepts/arithmetic.h b/libcxx/include/__concepts/arithmetic.h
index 0c44f117805f3..64c0200783df7 100644
--- a/libcxx/include/__concepts/arithmetic.h
+++ b/libcxx/include/__concepts/arithmetic.h
@@ -13,8 +13,6 @@
 #include <__type_traits/is_floating_point.h>
 #include <__type_traits/is_integral.h>
 #include <__type_traits/is_signed.h>
-#include <__type_traits/is_signed_integer.h>
-#include <__type_traits/is_unsigned_integer.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -38,17 +36,6 @@ concept unsigned_integral = integral<_Tp> && !signed_integral<_Tp>;
 template <class _Tp>
 concept floating_point = is_floating_point_v<_Tp>;
 
-// Concept helpers for the internal type traits for the fundamental types.
-
-template <class _Tp>
-concept __libcpp_unsigned_integer = __libcpp_is_unsigned_integer<_Tp>::value;
-
-template <class _Tp>
-concept __libcpp_signed_integer = __libcpp_is_signed_integer<_Tp>::value;
-
-template <class _Tp>
-concept __libcpp_integer = __libcpp_unsigned_integer<_Tp> || __libcpp_signed_integer<_Tp>;
-
 #endif // _LIBCPP_STD_VER >= 20
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__format/format_arg_store.h b/libcxx/include/__format/format_arg_store.h
index 87557aa4da7bb..fbb4cad21b232 100644
--- a/libcxx/include/__format/format_arg_store.h
+++ b/libcxx/include/__format/format_arg_store.h
@@ -14,7 +14,6 @@
 #  pragma GCC system_header
 #endif
 
-#include <__concepts/arithmetic.h>
 #include <__concepts/same_as.h>
 #include <__config>
 #include <__cstddef/size_t.h>
@@ -22,6 +21,7 @@
 #include <__format/format_arg.h>
 #include <__type_traits/conditional.h>
 #include <__type_traits/extent.h>
+#include <__type_traits/integer_traits.h>
 #include <__type_traits/remove_const.h>
 #include <cstdint>
 #include <string>
@@ -65,7 +65,7 @@ consteval __arg_t __determine_arg_t() {
 #  endif
 
 // Signed integers
-template <class, __libcpp_signed_integer _Tp>
+template <class, __signed_integer _Tp>
 consteval __arg_t __determine_arg_t() {
   if constexpr (sizeof(_Tp) <= sizeof(int))
     return __arg_t::__int;
@@ -80,7 +80,7 @@ consteval __arg_t __determine_arg_t() {
 }
 
 // Unsigned integers
-template <class, __libcpp_unsigned_integer _Tp>
+template <class, __unsigned_integer _Tp>
 consteval __arg_t __determine_arg_t() {
   if constexpr (sizeof(_Tp) <= sizeof(unsigned))
     return __arg_t::__unsigned;
diff --git a/libcxx/include/__mdspan/extents.h b/libcxx/include/__mdspan/extents.h
index 00454004851d5..99b54badf893c 100644
--- a/libcxx/include/__mdspan/extents.h
+++ b/libcxx/include/__mdspan/extents.h
@@ -21,11 +21,10 @@
 #include <__config>
 
 #include <__concepts/arithmetic.h>
-#include <__cstddef/byte.h>
 #include <__type_traits/common_type.h>
+#include <__type_traits/integer_traits.h>
 #include <__type_traits/is_convertible.h>
 #include <__type_traits/is_nothrow_constructible.h>
-#include <__type_traits/is_same.h>
 #include <__type_traits/make_unsigned.h>
 #include <__utility/integer_sequence.h>
 #include <__utility/unreachable.h>
@@ -283,7 +282,8 @@ class extents {
   using size_type  = make_unsigned_t<index_type>;
   using rank_type  = size_t;
 
-  static_assert(__libcpp_integer<index_type>, "extents::index_type must be a signed or unsigned integer type");
+  static_assert(__signed_or_unsigned_integer<index_type>,
+                "extents::index_type must be a signed or unsigned integer type");
   static_assert(((__mdspan_detail::__is_representable_as<index_type>(_Extents) || (_Extents == dynamic_extent)) && ...),
                 "extents ctor: arguments must be representable as index_type and nonnegative");
 
diff --git a/libcxx/include/__numeric/saturation_arithmetic.h b/libcxx/include/__numeric/saturation_arithmetic.h
index 4110a8cb142a5..9bd3af12c9572 100644
--- a/libcxx/include/__numeric/saturation_arithmetic.h
+++ b/libcxx/include/__numeric/saturation_arithmetic.h
@@ -11,9 +11,9 @@
 #define _LIBCPP___NUMERIC_SATURATION_ARITHMETIC_H
 
 #include <__assert>
-#include <__concepts/arithmetic.h>
 #include <__config>
 #include <__memory/addressof.h>
+#include <__type_traits/integer_traits.h>
 #include <__utility/cmp.h>
 #include <limits>
 
@@ -28,12 +28,12 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 20
 
-template <__libcpp_integer _Tp>
+template <__signed_or_unsigned_integer _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr _Tp __add_sat(_Tp __x, _Tp __y) noexcept {
   if (_Tp __sum; !__builtin_add_overflow(__x, __y, std::addressof(__sum)))
     return __sum;
   // Handle overflow
-  if constexpr (__libcpp_unsigned_integer<_Tp>) {
+  if constexpr (__unsigned_integer<_Tp>) {
     return std::numeric_limits<_Tp>::max();
   } else {
     // Signed addition overflow
@@ -46,12 +46,12 @@ _LIBCPP_HIDE_FROM_ABI constexpr _Tp __add_sat(_Tp __x, _Tp __y) noexcept {
   }
 }
 
-template <__libcpp_integer _Tp>
+template <__signed_or_unsigned_integer _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr _Tp __sub_sat(_Tp __x, _Tp __y) noexcept {
   if (_Tp __sub; !__builtin_sub_overflow(__x, __y, std::addressof(__sub)))
     return __sub;
   // Handle overflow
-  if constexpr (__libcpp_unsigned_integer<_Tp>) {
+  if constexpr (__unsigned_integer<_Tp>) {
     // Overflows if (x < y)
     return std::numeric_limits<_Tp>::min();
   } else {
@@ -65,12 +65,12 @@ _LIBCPP_HIDE_FROM_ABI constexpr _Tp __sub_sat(_Tp __x, _Tp __y) noexcept {
   }
 }
 
-template <__libcpp_integer _Tp>
+template <__signed_or_unsigned_integer _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr _Tp __mul_sat(_Tp __x, _Tp __y) noexcept {
   if (_Tp __mul; !__builtin_mul_overflow(__x, __y, std::addressof(__mul)))
     return __mul;
   // Handle overflow
-  if constexpr (__libcpp_unsigned_integer<_Tp>) {
+  if constexpr (__unsigned_integer<_Tp>) {
     return std::numeric_limits<_Tp>::max();
   } else {
     // Signed multiplication overflow
@@ -81,10 +81,10 @@ _LIBCPP_HIDE_FROM_ABI constexpr _Tp __mul_sat(_Tp __x, _Tp __y) noexcept {
   }
 }
 
-template <__libcpp_integer _Tp>
+template <__signed_or_unsigned_integer _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr _Tp __div_sat(_Tp __x, _Tp __y) noexcept {
   _LIBCPP_ASSERT_UNCATEGORIZED(__y != 0, "Division by 0 is undefined");
-  if constexpr (__libcpp_unsigned_integer<_Tp>) {
+  if constexpr (__unsigned_integer<_Tp>) {
     return __x / __y;
   } else {
     // Handle signed division overflow
@@ -94,7 +94,7 @@ _LIBCPP_HIDE_FROM_ABI constexpr _Tp __div_sat(_Tp __x, _Tp __y) noexcept {
   }
 }
 
-template <__libcpp_integer _Rp, __libcpp_integer _Tp>
+template <__signed_or_unsigned_integer _Rp, __signed_or_unsigned_integer _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr _Rp __saturate_cast(_Tp __x) noexcept {
   // Saturation is impossible edge case when ((min _Rp) < (min _Tp) && (max _Rp) > (max _Tp)) and it is expected to be
   // optimized out by the compiler.
@@ -112,27 +112,27 @@ _LIBCPP_HIDE_FROM_ABI constexpr _Rp __saturate_cast(_Tp __x) noexcept {
 
 #if _LIBCPP_STD_VER >= 26
 
-template <__libcpp_integer _Tp>
+template <__signed_or_unsigned_integer _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr _Tp add_sat(_Tp __x, _Tp __y) noexcept {
   return std::__add_sat(__x, __y);
 }
 
-template <__libcpp_integer _Tp>
+template <__signed_or_unsigned_integer _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr _Tp sub_sat(_Tp __x, _Tp __y) noexcept {
   return std::__sub_sat(__x, __y);
 }
 
-template <__libcpp_integer _Tp>
+template <__signed_or_unsigned_integer _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr _Tp mul_sat(_Tp __x, _Tp __y) noexcept {
   return std::__mul_sat(__x, __y);
 }
 
-template <__libcpp_integer _Tp>
+template <__signed_or_unsigned_integer _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr _Tp div_sat(_Tp __x, _Tp __y) noexcept {
   return std::__div_sat(__x, __y);
 }
 
-template <__libcpp_integer _Rp, __libcpp_integer _Tp>
+template <__signed_or_unsigned_integer _Rp, __signed_or_unsigned_integer _Tp>
 _LIBCPP_HIDE_FROM_ABI constexpr _Rp saturate_cast(_Tp __x) noexcept {
   return std::__saturate_cast<_Rp>(__x);
 }
diff --git a/libcxx/include/__type_traits/integer_traits.h b/libcxx/include/__type_traits/integer_traits.h
new file mode 100644
index 0000000000000..fad502c44e301
--- /dev/null
+++ b/libcxx/include/__type_traits/integer_traits.h
@@ -0,0 +1,73 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___TYPE_TRAITS_INTEGER_TRAITS_H
+#define _LIBCPP___TYPE_TRAITS_INTEGER_TRAITS_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// This trait is to determine whether a type is a /signed integer type/
+// See [basic.fundamental]/p1
+template <class _Tp>
+inline const bool __is_signed_integer_v = false;
+template <>
+inline const bool __is_signed_integer_v<signed char> = true;
+template <>
+inline const bool __is_signed_integer_v<signed short> = true;
+template <>
+inline const bool __is_signed_integer_v<signed int> = true;
+template <>
+inline const bool __is_signed_integer_v<signed long> = true;
+template <>
+inline const bool __is_signed_integer_v<signed long long> = true;
+#if _LIBCPP_HAS_INT128
+template <>
+inline const bool __is_signed_integer_v<__int128_t> = true;
+#endif
+
+// This trait is to determine whether a type is an /unsigned integer type/
+// See [basic.fundamental]/p2
+template <class _Tp>
+inline const bool __is_uns...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/142750
