util: Add SaturatingAdd helper

1 files changed, 13 insertions, 4 deletions

diff --git a/src/test/fuzz/addition_overflow.cpp b/src/test/fuzz/addition_overflow.cpp
index cfad41659e..372c1a370e 100644
--- a/src/test/fuzz/addition_overflow.cpp
+++ b/src/test/fuzz/addition_overflow.cpp
@@ -26,6 +26,12 @@ void TestAdditionOverflow(FuzzedDataProvider& fuzzed_data_provider)
     const T i = fuzzed_data_provider.ConsumeIntegral<T>();
     const T j = fuzzed_data_provider.ConsumeIntegral<T>();
     const bool is_addition_overflow_custom = AdditionOverflow(i, j);
+    const auto maybe_add{CheckedAdd(i, j)};
+    const auto sat_add{SaturatingAdd(i, j)};
+    assert(is_addition_overflow_custom == !maybe_add.has_value());
+    assert(is_addition_overflow_custom == AdditionOverflow(j, i));
+    assert(maybe_add == CheckedAdd(j, i));
+    assert(sat_add == SaturatingAdd(j, i));
 #if defined(HAVE_BUILTIN_ADD_OVERFLOW)
     T result_builtin;
     const bool is_addition_overflow_builtin = __builtin_add_overflow(i, j, &result_builtin);
@@ -33,11 +39,14 @@ void TestAdditionOverflow(FuzzedDataProvider& fuzzed_data_provider)
     if (!is_addition_overflow_custom) {
         assert(i + j == result_builtin);
     }
-#else
-    if (!is_addition_overflow_custom) {
-        (void)(i + j);
-    }
 #endif
+    if (is_addition_overflow_custom) {
+        assert(sat_add == std::numeric_limits<T>::min() || sat_add == std::numeric_limits<T>::max());
+    } else {
+        const auto add{i + j};
+        assert(add == maybe_add.value());
+        assert(add == sat_add);
+    }
 }
 } // namespace