1 files changed, 90 insertions, 0 deletions
diff --git a/test/libcxx/numerics/clamp_to_integral.pass.cpp b/test/libcxx/numerics/clamp_to_integral.pass.cpp
new file mode 100644
index 000000000..cb3336f52
--- /dev/null
+++ b/test/libcxx/numerics/clamp_to_integral.pass.cpp
@@ -0,0 +1,90 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// __clamp_to_integral<IntT>(RealT)
+
+// Test the conversion function that truncates floating point types to the
+// closest representable value for the specified integer type, or
+// numeric_limits<IntT>::max()/min() if the value isn't representable.
+
+#include <limits>
+#include <cassert>
+#include <cmath>
+
+template <class IntT>
+void test() {
+  typedef std::numeric_limits<IntT> Lim;
+  const bool MaxIsRepresentable = sizeof(IntT) < 8;
+  const bool IsSigned = std::is_signed<IntT>::value;
+  struct TestCase {
+    double Input;
+    IntT Expect;
+    bool IsRepresentable;
+  } TestCases[] = {
+      {0, 0, true},
+      {1, 1, true},
+      {IsSigned ? static_cast<IntT>(-1) : 0,
+       IsSigned ? static_cast<IntT>(-1) : 0, true},
+      {Lim::lowest(), Lim::lowest(), true},
+      {static_cast<double>(Lim::max()), Lim::max(), MaxIsRepresentable},
+      {static_cast<double>(Lim::max()) + 1, Lim::max(), false},
+      {static_cast<double>(Lim::max()) + 1024, Lim::max(), false},
+      {nextafter(static_cast<double>(Lim::max()), INFINITY), Lim::max(), false},
+  };
+  for (TestCase TC : TestCases) {
+    auto res = std::__clamp_to_integral<IntT>(TC.Input);
+    assert(res == TC.Expect);
+    if (TC.IsRepresentable) {
+      auto other = static_cast<IntT>(std::trunc(TC.Input));
+      assert(res == other);
+    } else
+      assert(res == Lim::min() || res == Lim::max());
+  }
+}
+
+template <class IntT>
+void test_float() {
+  typedef std::numeric_limits<IntT> Lim;
+  const bool MaxIsRepresentable = sizeof(IntT) < 4;
+  ((void)MaxIsRepresentable);
+  const bool IsSigned = std::is_signed<IntT>::value;
+  struct TestCase {
+    float Input;
+    IntT Expect;
+    bool IsRepresentable;
+  } TestCases[] = {
+      {0, 0, true},
+      {1, 1, true},
+      {IsSigned ? static_cast<IntT>(-1) : 0,
+       IsSigned ? static_cast<IntT>(-1) : 0, true},
+      {Lim::lowest(), Lim::lowest(), true},
+      {static_cast<float>(Lim::max()), Lim::max(), MaxIsRepresentable },
+       {nextafter(static_cast<float>(Lim::max()), INFINITY), Lim::max(), false},
+  };
+  for (TestCase TC : TestCases) {
+    auto res = std::__clamp_to_integral<IntT>(TC.Input);
+    assert(res == TC.Expect);
+    if (TC.IsRepresentable) {
+      auto other = static_cast<IntT>(std::trunc(TC.Input));
+      assert(res == other);
+    } else
+      assert(res == Lim::min() || res == Lim::max());
+  }
+}
+
+int main() {
+  test<short>();
+  test<unsigned short>();
+  test<int>();
+  test<unsigned>();
+  test<long long>();
+  test<unsigned long long>();
+  test_float<short>();
+  test_float<int>();
+  test_float<long long>();
+}