diff --git a/src/bindgen/ir/constant.rs b/src/bindgen/ir/constant.rs
index 67d0bf79..9c7a1401 100644
--- a/src/bindgen/ir/constant.rs
+++ b/src/bindgen/ir/constant.rs
@@ -163,7 +163,11 @@ impl Literal {
                         other_code => format!(r"L'\U{:08X}'", other_code),
                     })),
                     syn::Lit::Int(ref value) => {
-                        Ok(Literal::Expr(value.base10_digits().to_string()))
+                        if value.base10_parse::<i64>().is_err() {
+                            Ok(Literal::Expr(format!("{}ULL", value.base10_digits())))
+                        } else {
+                            Ok(Literal::Expr(value.base10_digits().to_string()))
+                        }
                     }
                     syn::Lit::Float(ref value) => {
                         Ok(Literal::Expr(value.base10_digits().to_string()))
diff --git a/tests/expectations/both/constant_big.c b/tests/expectations/both/constant_big.c
new file mode 100644
index 00000000..469bf315
--- /dev/null
+++ b/tests/expectations/both/constant_big.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define SIGNED_DOESNT_NEED_ULL_SUFFIX -9223372036854775807
+
+#define SIGNED_NEEDS_ULL_SUFFIX -9223372036854775808ULL
+
+#define UNSIGNED_DOESNT_NEED_ULL_SUFFIX 8070450532247928832
+
+#define UNSIGNED_NEEDS_ULL_SUFFIX 9223372036854775808ULL
diff --git a/tests/expectations/both/constant_big.compat.c b/tests/expectations/both/constant_big.compat.c
new file mode 100644
index 00000000..469bf315
--- /dev/null
+++ b/tests/expectations/both/constant_big.compat.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define SIGNED_DOESNT_NEED_ULL_SUFFIX -9223372036854775807
+
+#define SIGNED_NEEDS_ULL_SUFFIX -9223372036854775808ULL
+
+#define UNSIGNED_DOESNT_NEED_ULL_SUFFIX 8070450532247928832
+
+#define UNSIGNED_NEEDS_ULL_SUFFIX 9223372036854775808ULL
diff --git a/tests/expectations/constant_big.c b/tests/expectations/constant_big.c
new file mode 100644
index 00000000..469bf315
--- /dev/null
+++ b/tests/expectations/constant_big.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define SIGNED_DOESNT_NEED_ULL_SUFFIX -9223372036854775807
+
+#define SIGNED_NEEDS_ULL_SUFFIX -9223372036854775808ULL
+
+#define UNSIGNED_DOESNT_NEED_ULL_SUFFIX 8070450532247928832
+
+#define UNSIGNED_NEEDS_ULL_SUFFIX 9223372036854775808ULL
diff --git a/tests/expectations/constant_big.compat.c b/tests/expectations/constant_big.compat.c
new file mode 100644
index 00000000..469bf315
--- /dev/null
+++ b/tests/expectations/constant_big.compat.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define SIGNED_DOESNT_NEED_ULL_SUFFIX -9223372036854775807
+
+#define SIGNED_NEEDS_ULL_SUFFIX -9223372036854775808ULL
+
+#define UNSIGNED_DOESNT_NEED_ULL_SUFFIX 8070450532247928832
+
+#define UNSIGNED_NEEDS_ULL_SUFFIX 9223372036854775808ULL
diff --git a/tests/expectations/constant_big.cpp b/tests/expectations/constant_big.cpp
new file mode 100644
index 00000000..e52f8f3e
--- /dev/null
+++ b/tests/expectations/constant_big.cpp
@@ -0,0 +1,12 @@
+#include <cstdarg>
+#include <cstdint>
+#include <cstdlib>
+#include <new>
+
+static const int64_t SIGNED_DOESNT_NEED_ULL_SUFFIX = -9223372036854775807;
+
+static const int64_t SIGNED_NEEDS_ULL_SUFFIX = -9223372036854775808ULL;
+
+static const uint64_t UNSIGNED_DOESNT_NEED_ULL_SUFFIX = 8070450532247928832;
+
+static const uint64_t UNSIGNED_NEEDS_ULL_SUFFIX = 9223372036854775808ULL;
diff --git a/tests/expectations/tag/constant_big.c b/tests/expectations/tag/constant_big.c
new file mode 100644
index 00000000..469bf315
--- /dev/null
+++ b/tests/expectations/tag/constant_big.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define SIGNED_DOESNT_NEED_ULL_SUFFIX -9223372036854775807
+
+#define SIGNED_NEEDS_ULL_SUFFIX -9223372036854775808ULL
+
+#define UNSIGNED_DOESNT_NEED_ULL_SUFFIX 8070450532247928832
+
+#define UNSIGNED_NEEDS_ULL_SUFFIX 9223372036854775808ULL
diff --git a/tests/expectations/tag/constant_big.compat.c b/tests/expectations/tag/constant_big.compat.c
new file mode 100644
index 00000000..469bf315
--- /dev/null
+++ b/tests/expectations/tag/constant_big.compat.c
@@ -0,0 +1,12 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define SIGNED_DOESNT_NEED_ULL_SUFFIX -9223372036854775807
+
+#define SIGNED_NEEDS_ULL_SUFFIX -9223372036854775808ULL
+
+#define UNSIGNED_DOESNT_NEED_ULL_SUFFIX 8070450532247928832
+
+#define UNSIGNED_NEEDS_ULL_SUFFIX 9223372036854775808ULL
diff --git a/tests/rust/constant_big.rs b/tests/rust/constant_big.rs
new file mode 100644
index 00000000..94eb834f
--- /dev/null
+++ b/tests/rust/constant_big.rs
@@ -0,0 +1,8 @@
+pub const UNSIGNED_NEEDS_ULL_SUFFIX: u64       = 0x8000_0000_0000_0000;
+pub const UNSIGNED_DOESNT_NEED_ULL_SUFFIX: u64 = 0x7000_0000_0000_0000;
+
+// i64::min_value()
+pub const SIGNED_NEEDS_ULL_SUFFIX: i64         = -9223372036854775808;
+
+// i64::min_value() + 1
+pub const SIGNED_DOESNT_NEED_ULL_SUFFIX: i64   = -9223372036854775807;