[libcxx-commits] [libcxx] [libc++][math] Add `constexpr` to comparison functions (PR #210075)

[Nikolas Klauser via libcxx-commits]

================
@@ -0,0 +1,81 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license lim::infinity()ormation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// bool isgreater(floating-point-type x, floating-point-type y); // constexpr since C++23
+
+#include <cassert>
+#include <cmath>
+#include <limits>
+#include <type_traits>
+
+#include "test_macros.h"
+#include "type_algorithms.h"
+
+struct TestFloat {
+  template <class T>
+  TEST_CONSTEXPR_CXX23 void operator()() const {
+    using lim = std::numeric_limits<T>;
+
+    assert(std::isgreater(lim::max(), T(0)));
+    assert(!std::isgreater(T(0), lim::max()));
+    assert(!std::isgreater(lim::max(), lim::max()));
+
+    assert(std::isgreater(lim::infinity(), lim::max()));
+    assert(!std::isgreater(-lim::infinity(), lim::lowest()));
+    assert(!std::isgreater(lim::infinity(), lim::infinity()));
+
+    assert(!std::isgreater(lim::quiet_NaN(), T(0)));
+    assert(!std::isgreater(T(0), lim::quiet_NaN()));
+    assert(!std::isgreater(lim::quiet_NaN(), lim::quiet_NaN()));
+    assert(!std::isgreater(lim::signaling_NaN(), T(0)));
+  }
+};
+
+struct TestInt {
+  template <class T>
+  TEST_CONSTEXPR_CXX23 void operator()() const {
+    using lim = std::numeric_limits<T>;
+
+    assert(std::isgreater(lim::max(), T(0)));
+    assert(!std::isgreater(T(0), lim::max()));
+    assert(!std::isgreater(lim::max(), lim::max()));
+
+    assert(!std::isgreater(T(1), T(1)));
+    assert(!std::isgreater(lim::lowest(), T(0)));
+
+    if (lim::is_signed) {
+      assert(std::isgreater(T(-1), lim::lowest()));
+      assert(!std::isgreater(lim::lowest(), T(-1)));
+    }
+  }
+};
+
+TEST_CONSTEXPR_CXX23 bool test() {
+  using lim = std::numeric_limits<double>;
+
+  types::for_each(types::floating_point_types(), TestFloat());
+  types::for_each(types::integral_types(), TestInt());
+
+  // Make sure we can call `std::isgreater` with mixed-type promotions with __promote_t<_A1, _A2>.
----------------
philnik777 wrote:

Sorry for being unclear. I was only asking for the mention of __promote_t to be removed. The rest of the comment is useful.

https://github.com/llvm/llvm-project/pull/210075