1 files changed, 22 insertions, 0 deletions
diff --git a/libstdc++-v3/testsuite/26_numerics/lcm/105844.cc b/libstdc++-v3/testsuite/26_numerics/lcm/105844.cc
new file mode 100644
index 00000000000..d0e032e03e0
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/lcm/105844.cc
@@ -0,0 +1,22 @@
+// { dg-do compile { target c++17 } }
+#include <numeric>
+#include <climits>
+
+// PR libstdc++/105844
+
+// |INT_MIN| can be represented in common_type_t<int, unsigned> i.e. unsigned.
+static_assert( std::lcm(INT_MIN, 1u) == INT_MAX+1u );
+static_assert( std::lcm(1u, INT_MIN) == INT_MAX+1u );
+
+// But |INT_MIN| cannot be represented in common_type<int, int> i.e. int.
+constexpr int a = std::lcm(INT_MIN, 1); // { dg-error "overflow" }
+constexpr int b = std::lcm(1, INT_MIN); // { dg-error "overflow" }
+
+// And the LCM of 50000 and 49999 cannot be represented in int.
+constexpr int c = std::lcm(50000, 49999); // { dg-error "overflow" }
+constexpr int d = std::lcm(49999, 50000); // { dg-error "overflow" }
+
+// Similarly for unsigned, but the diagnostic is a failed assertion instead.
+constexpr int e = std::lcm(500000u, 499999); // { dg-error "in 'constexpr'" }
+constexpr int f = std::lcm(499999u, 500000); // { dg-error "in 'constexpr'" }
+// { dg-error "unreachable" "" { target *-*-* } 0 }