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@@ -0,0 +1,267 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20, c++23
+
+// <numeric>
+
+// template<class T>
+// constexpr T div_sat(T x, T y) noexcept; // freestanding
+
+#include <cassert>
+#include <concepts>
+#include <limits>
+#include <numeric>
+
+template <typename IntegerT>
+constexpr bool test_signed() {
+ constexpr auto minVal = std::numeric_limits<IntegerT>::min();
+ constexpr auto maxVal = std::numeric_limits<IntegerT>::max();
+
+ static_assert(noexcept(std::div_sat(minVal, maxVal)));
+
+ // No saturation
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{-1}, IntegerT{-1});
+ assert(quot == IntegerT{1});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{-1}, IntegerT{1});
+ assert(quot == IntegerT{-1});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{-1}, minVal);
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{-1}, maxVal);
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(maxVal, IntegerT{-1});
+ assert(quot == IntegerT{-1} * maxVal);
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{0}, IntegerT{-1});
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{0}, IntegerT{1});
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{0}, minVal);
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{1}, IntegerT{-1});
+ assert(quot == IntegerT{-1});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{1}, minVal);
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{1}, maxVal);
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(minVal, IntegerT{1});
+ assert(quot == minVal);
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(maxVal, IntegerT{1});
+ assert(quot == maxVal);
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{27}, IntegerT{28});
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{28}, IntegerT{27});
+ assert(quot == IntegerT{1});
+ }
+
+ {
+ // Large values
+ constexpr IntegerT x = minVal / IntegerT{2} + IntegerT{-27};
+ constexpr IntegerT y = maxVal / IntegerT{2} + IntegerT{28};
+
+ std::same_as<IntegerT> decltype(auto) sum = std::div_sat(x, y);
+ assert(sum == IntegerT{-1});
+ }
+
+ {
+ // Large values
+ constexpr IntegerT x = maxVal / IntegerT{2} + IntegerT{28};
+ constexpr IntegerT y = minVal / IntegerT{2} + IntegerT{-27};
+
+ std::same_as<IntegerT> decltype(auto) sum = std::div_sat(x, y);
+ assert(sum == IntegerT{-1});
+ }
+
+ {
+ // Large values
+ constexpr IntegerT x = minVal / IntegerT{2} + IntegerT{-27};
+ constexpr IntegerT y = minVal / IntegerT{2} + IntegerT{-28};
+
+ std::same_as<IntegerT> decltype(auto) sum = std::div_sat(x, y);
+ assert(sum == IntegerT{0});
+ }
+
+ {
+ // Large values
+ constexpr IntegerT x = minVal / IntegerT{2} + IntegerT{-28};
+ constexpr IntegerT y = minVal / IntegerT{2} + IntegerT{-27};
+
+ std::same_as<IntegerT> decltype(auto) sum = std::div_sat(x, y);
+ assert(sum == IntegerT{1});
+ }
+
+ {
+ // Large values
+ constexpr IntegerT x = maxVal / IntegerT{2} + IntegerT{27};
+ constexpr IntegerT y = maxVal / IntegerT{2} + IntegerT{28};
+
+ std::same_as<IntegerT> decltype(auto) sum = std::div_sat(x, y);
+ assert(sum == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(maxVal, minVal);
+ assert(quot == (maxVal / minVal));
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(minVal, maxVal);
+ assert(quot == (minVal / maxVal));
+ }
+
+ // Saturation - max only
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(minVal, IntegerT{-1});
+ assert(quot == maxVal);
+ }
+
+ return true;
+}
+
+template <typename IntegerT>
+constexpr bool test_unsigned() {
+ constexpr auto minVal = std::numeric_limits<IntegerT>::min();
+ constexpr auto maxVal = std::numeric_limits<IntegerT>::max();
+
+ static_assert(noexcept(std::div_sat(minVal, maxVal)));
+
+ // No saturation
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{0}, IntegerT{1});
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{0}, maxVal);
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{1}, IntegerT{1});
+ assert(quot == IntegerT{1});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{1}, maxVal);
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{27}, IntegerT{28});
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(IntegerT{28}, IntegerT{27});
+ assert(quot == IntegerT{1});
+ }
+
+ {
+ // Large values
+ constexpr IntegerT x = maxVal / IntegerT{2} + IntegerT{27};
+ constexpr IntegerT y = maxVal / IntegerT{2} + IntegerT{28};
+
+ std::same_as<IntegerT> decltype(auto) sum = std::div_sat(x, y);
+ assert(sum == IntegerT{0});
+ }
+
+ {
+ // Large values
+ constexpr IntegerT x = maxVal / IntegerT{2} + IntegerT{28};
+ constexpr IntegerT y = maxVal / IntegerT{2} + IntegerT{27};
+
+ std::same_as<IntegerT> decltype(auto) sum = std::div_sat(x, y);
+ assert(sum == IntegerT{1});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(minVal, maxVal);
+ assert(quot == IntegerT{0});
+ }
+
+ {
+ std::same_as<IntegerT> decltype(auto) quot = std::div_sat(maxVal, maxVal);
+ assert(quot == IntegerT{1});
+ }
+
+ // Unsigned integer devision never overflows
----------------
mordante wrote:
```suggestion
// Unsigned integer division never overflows
```
https://github.com/llvm/llvm-project/pull/77967