[libc-commits] [libc] Added support of fixed-points in ``is_signed`` and ``is_unsigned``. (PR #133371)

[Abhinav Kumar via libc-commits]

https://github.com/kr-2003 created https://github.com/llvm/llvm-project/pull/133371

Fixes #133365



>From d967f431f9382ab80dc034450251ea8c32fa1537 Mon Sep 17 00:00:00 2001
From: kr-2003 <kumar.kr.abhinav at gmail.com>
Date: Fri, 28 Mar 2025 11:13:44 +0530
Subject: [PATCH] added support of fixed-points in is_signed and is_unsigned

---
 .../src/__support/CPP/type_traits/is_signed.h | 69 ++++++++++++++++++-
 .../__support/CPP/type_traits/is_unsigned.h   | 69 ++++++++++++++++++-
 .../src/__support/CPP/type_traits_test.cpp    | 61 +++++++++++++++-
 3 files changed, 193 insertions(+), 6 deletions(-)

diff --git a/libc/src/__support/CPP/type_traits/is_signed.h b/libc/src/__support/CPP/type_traits/is_signed.h
index 3f56fb38aabb0..699b017eda183 100644
--- a/libc/src/__support/CPP/type_traits/is_signed.h
+++ b/libc/src/__support/CPP/type_traits/is_signed.h
@@ -8,20 +8,85 @@
 #ifndef LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_IS_SIGNED_H
 #define LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_IS_SIGNED_H
 
+#include "include/llvm-libc-macros/stdfix-macros.h"
 #include "src/__support/CPP/type_traits/bool_constant.h"
 #include "src/__support/CPP/type_traits/is_arithmetic.h"
+#include "src/__support/CPP/type_traits/is_fixed_point.h"
 #include "src/__support/macros/attributes.h"
 #include "src/__support/macros/config.h"
 
 namespace LIBC_NAMESPACE_DECL {
 namespace cpp {
 
-// is_signed
+// Primary template: handles arithmetic and signed fixed-point types
 template <typename T>
-struct is_signed : bool_constant<(is_arithmetic_v<T> && (T(-1) < T(0)))> {
+struct is_signed : bool_constant<((is_fixed_point_v<T> || is_arithmetic_v<T>) && (T(-1) < T(0)))> {
   LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
   LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
 };
+
+// Specializations for unsigned fixed-point types
+template <>
+struct is_signed<unsigned short fract> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned fract> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned long fract> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned short accum> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned accum> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned long accum> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned short sat fract> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned sat fract> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned long sat fract> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned short sat accum> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned sat accum> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+template <>
+struct is_signed<unsigned long sat accum> : bool_constant<false> {
+  LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
+};
+
 template <typename T>
 LIBC_INLINE_VAR constexpr bool is_signed_v = is_signed<T>::value;
 
diff --git a/libc/src/__support/CPP/type_traits/is_unsigned.h b/libc/src/__support/CPP/type_traits/is_unsigned.h
index eed519b1c067e..58cd3f0f598a9 100644
--- a/libc/src/__support/CPP/type_traits/is_unsigned.h
+++ b/libc/src/__support/CPP/type_traits/is_unsigned.h
@@ -8,20 +8,85 @@
 #ifndef LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_IS_UNSIGNED_H
 #define LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_IS_UNSIGNED_H
 
+#include "include/llvm-libc-macros/stdfix-macros.h"
 #include "src/__support/CPP/type_traits/bool_constant.h"
 #include "src/__support/CPP/type_traits/is_arithmetic.h"
+#include "src/__support/CPP/type_traits/is_fixed_point.h"
 #include "src/__support/macros/attributes.h"
 #include "src/__support/macros/config.h"
 
 namespace LIBC_NAMESPACE_DECL {
 namespace cpp {
 
-// is_unsigned
+// Primary template: handles arithmetic and signed fixed-point types
 template <typename T>
-struct is_unsigned : bool_constant<(is_arithmetic_v<T> && (T(-1) > T(0)))> {
+struct is_unsigned : bool_constant<((is_fixed_point_v<T> || is_arithmetic_v<T>) && (T(-1) > T(0)))> {
   LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
   LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
 };
+
+// Specializations for unsigned fixed-point types
+template <>
+struct is_unsigned<unsigned short fract> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned fract> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned long fract> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned short accum> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned accum> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned long accum> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned short sat fract> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned sat fract> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned long sat fract> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned short sat accum> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned sat accum> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+template <>
+struct is_unsigned<unsigned long sat accum> : bool_constant<true> {
+  LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
+  LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
+};
+
 template <typename T>
 LIBC_INLINE_VAR constexpr bool is_unsigned_v = is_unsigned<T>::value;
 
diff --git a/libc/test/src/__support/CPP/type_traits_test.cpp b/libc/test/src/__support/CPP/type_traits_test.cpp
index 4b3e48c6a6c0f..338705efa5e80 100644
--- a/libc/test/src/__support/CPP/type_traits_test.cpp
+++ b/libc/test/src/__support/CPP/type_traits_test.cpp
@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "include/llvm-libc-macros/stdfix-macros.h"
 #include "src/__support/CPP/type_traits.h"
 #include "src/__support/macros/config.h"
 #include "test/UnitTest/Test.h"
@@ -409,7 +410,35 @@ TEST(LlvmLibcTypeTraitsTest, is_object) {
 
 // TODO is_scalar
 
-// TODO is_signed
+TEST(LlvmLibcTypeTraitsTest, is_signed) {
+  EXPECT_TRUE((is_signed_v<int>));
+  EXPECT_TRUE((is_signed_v<long>));
+  EXPECT_TRUE((is_signed_v<long long>));
+  EXPECT_FALSE((is_signed_v<unsigned int>));
+  EXPECT_FALSE((is_signed_v<unsigned long>));
+  EXPECT_FALSE((is_signed_v<unsigned long long>));
+  EXPECT_TRUE((is_signed_v<float>));
+  EXPECT_TRUE((is_signed_v<double>));
+  EXPECT_TRUE((is_signed_v<long double>));
+
+  // for fixed point types
+  EXPECT_TRUE((is_signed_v<fract>));
+  EXPECT_FALSE((is_signed_v<unsigned fract>));
+  EXPECT_TRUE((is_signed_v<accum>));
+  EXPECT_FALSE((is_signed_v<unsigned accum>));
+  EXPECT_TRUE((is_signed_v<sat fract>));
+  EXPECT_FALSE((is_signed_v<unsigned sat fract>));
+  EXPECT_TRUE((is_signed_v<sat accum>));
+  EXPECT_FALSE((is_signed_v<unsigned sat accum>));
+  EXPECT_TRUE((is_signed_v<short fract>));
+  EXPECT_FALSE((is_signed_v<unsigned short fract>));
+  EXPECT_TRUE((is_signed_v<short accum>));
+  EXPECT_FALSE((is_signed_v<unsigned short accum>));
+  EXPECT_TRUE((is_signed_v<long fract>));
+  EXPECT_FALSE((is_signed_v<unsigned long fract>));
+  EXPECT_TRUE((is_signed_v<long accum>));
+  EXPECT_FALSE((is_signed_v<unsigned long accum>));
+}
 
 // TODO is_trivially_constructible
 
@@ -419,7 +448,35 @@ TEST(LlvmLibcTypeTraitsTest, is_object) {
 
 // TODO is_union
 
-// TODO is_unsigned
+TEST(LlvmLibcTypeTraitsTest, is_unsigned) {
+  EXPECT_FALSE((is_unsigned_v<int>));
+  EXPECT_FALSE((is_unsigned_v<long>));
+  EXPECT_FALSE((is_unsigned_v<long long>));
+  EXPECT_TRUE((is_unsigned_v<unsigned int>));
+  EXPECT_TRUE((is_unsigned_v<unsigned long>));
+  EXPECT_TRUE((is_unsigned_v<unsigned long long>));
+  EXPECT_FALSE((is_unsigned_v<float>));
+  EXPECT_FALSE((is_unsigned_v<double>));
+  EXPECT_FALSE((is_unsigned_v<long double>));
+
+  // for fixed point types
+  EXPECT_FALSE((is_unsigned_v<fract>));
+  EXPECT_TRUE((is_unsigned_v<unsigned fract>));
+  EXPECT_FALSE((is_unsigned_v<accum>));
+  EXPECT_TRUE((is_unsigned_v<unsigned accum>));
+  EXPECT_FALSE((is_unsigned_v<sat fract>));
+  EXPECT_TRUE((is_unsigned_v<unsigned sat fract>));
+  EXPECT_FALSE((is_unsigned_v<sat accum>));
+  EXPECT_TRUE((is_unsigned_v<unsigned sat accum>));
+  EXPECT_FALSE((is_unsigned_v<short fract>));
+  EXPECT_TRUE((is_unsigned_v<unsigned short fract>));
+  EXPECT_FALSE((is_unsigned_v<short accum>));
+  EXPECT_TRUE((is_unsigned_v<unsigned short accum>));
+  EXPECT_FALSE((is_unsigned_v<long fract>));
+  EXPECT_TRUE((is_unsigned_v<unsigned long fract>));
+  EXPECT_FALSE((is_unsigned_v<long accum>));
+  EXPECT_TRUE((is_unsigned_v<unsigned long accum>));
+}
 
 // TODO is_void