Test constexpr for signbit()

Author: robincaloudis

libcxx/test/libcxx/numerics/c.math/constexpr-cxx23-clang.pass.cpp

@@ -220,9 +220,9 @@ int main(int, char**) {
   ASSERT_CONSTEXPR_CXX23(std::isnormal(-1.0) == 1);
   ASSERT_CONSTEXPR_CXX23(std::isnormal(-1.0L) == 1);
 
-  ASSERT_NOT_CONSTEXPR_CXX23(std::signbit(-1.0f) == 1);
-  ASSERT_NOT_CONSTEXPR_CXX23(std::signbit(-1.0) == 1);
-  ASSERT_NOT_CONSTEXPR_CXX23(std::signbit(-1.0L) == 1);
+  ASSERT_CONSTEXPR_CXX23(std::signbit(-1.0f) == 1);
+  ASSERT_CONSTEXPR_CXX23(std::signbit(-1.0) == 1);
+  ASSERT_CONSTEXPR_CXX23(std::signbit(-1.0L) == 1);
 
   ASSERT_NOT_CONSTEXPR_CXX23(std::isgreater(-1.0f, 0.0f) == 0);
   ASSERT_NOT_CONSTEXPR_CXX23(std::isgreater(-1.0, 0.0) == 0);

libcxx/test/libcxx/numerics/c.math/constexpr-cxx23-gcc.pass.cpp

@@ -217,9 +217,9 @@ int main(int, char**) {
   ASSERT_CONSTEXPR_CXX23(std::isnormal(-1.0) == 1);
   ASSERT_CONSTEXPR_CXX23(std::isnormal(-1.0L) == 1);
 
-  ASSERT_NOT_CONSTEXPR_CXX23(std::signbit(-1.0f) == 1);
-  ASSERT_NOT_CONSTEXPR_CXX23(std::signbit(-1.0) == 1);
-  ASSERT_NOT_CONSTEXPR_CXX23(std::signbit(-1.0L) == 1);
+  ASSERT_CONSTEXPR_CXX23(std::signbit(-1.0f) == 1);
+  ASSERT_CONSTEXPR_CXX23(std::signbit(-1.0) == 1);
+  ASSERT_CONSTEXPR_CXX23(std::signbit(-1.0L) == 1);
 
   ASSERT_NOT_CONSTEXPR_CXX23(std::isgreater(-1.0f, 0.0f) == 0);
   ASSERT_NOT_CONSTEXPR_CXX23(std::isgreater(-1.0, 0.0) == 0);

libcxx/test/std/numerics/c.math/signbit.pass.cpp

@@ -0,0 +1,103 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// bool signbit(floating-point-type x); // constexpr since C++23
+
+// We don't control the implementation on windows
+// UNSUPPORTED: windows
+
+#include <cassert>
+#include <cmath>
+#include <limits>
+
+#include "test_macros.h"
+#include "type_algorithms.h"
+
+struct TestFloat {
+  template <class T>
+  static TEST_CONSTEXPR_CXX23 bool test() {
+    assert(!std::signbit(T(0)));
+    assert(std::signbit(-T(0)));
+    assert(std::signbit(std::numeric_limits<T>::lowest()));
+    assert(!std::signbit(std::numeric_limits<T>::min()));
+    assert(!std::signbit(std::numeric_limits<T>::denorm_min()));
+    assert(!std::signbit(std::numeric_limits<T>::max()));
+    assert(!std::signbit(std::numeric_limits<T>::infinity()));
+    assert(std::signbit(-std::numeric_limits<T>::infinity()));
+    assert(!std::signbit(std::numeric_limits<T>::quiet_NaN()));
+    assert(!std::signbit(std::numeric_limits<T>::signaling_NaN()));
+
+    return true;
+  }
+
+  template <class T>
+  TEST_CONSTEXPR_CXX23 void operator()() {
+    test<T>();
+#if TEST_STD_VER >= 23
+    static_assert(test<T>());
+#endif
+  }
+};
+
+struct TestUnsignedIntAndChar {
+  template <class T>
+  static TEST_CONSTEXPR_CXX23 bool test() {
+    assert(!std::signbit(std::numeric_limits<T>::max()));
+    assert(!std::signbit(std::numeric_limits<T>::lowest()));
+    assert(!std::signbit(T(0)));
+
+    return true;
+  }
+
+  template <class T>
+  TEST_CONSTEXPR_CXX23 void operator()() {
+    test<T>();
+#if TEST_STD_VER >= 23
+    static_assert(test<T>());
+#endif
+  }
+};
+
+struct TestSignedIntAndChar {
+  template <class T>
+  static TEST_CONSTEXPR_CXX23 bool test() {
+    assert(!std::signbit(std::numeric_limits<T>::max()));
+    assert(std::signbit(std::numeric_limits<T>::lowest()));
+    assert(!std::signbit(T(0)));
+
+    return true;
+  }
+
+  template <class T>
+  TEST_CONSTEXPR_CXX23 void operator()() {
+    test<T>();
+#if TEST_STD_VER >= 23
+    static_assert(test<T>());
+#endif
+  }
+};
+
+template <typename T>
+struct ConvertibleTo {
+  operator T() const { return T(); }
+};
+
+int main(int, char**) {
+  types::for_each(types::floating_point_types(), TestFloat());
+  types::for_each(types::concatenate_t<types::unsigned_integer_types, types::type_list<char8_t, char16_t, char32_t>>(), TestUnsignedIntAndChar());
+  types::for_each(types::concatenate_t<types::signed_integer_types, types::type_list<char>>(), TestSignedIntAndChar());
+
+  // Make sure we can call `std::signbit` with convertible types
+  {
+    assert(!std::signbit(ConvertibleTo<float>()));
+    assert(!std::signbit(ConvertibleTo<double>()));
+    assert(!std::signbit(ConvertibleTo<long double>()));
+  }
+
+  return 0;
+}