debuginfo: Use is unsigned flag when emitting enumerators

src/test/codegen/enum-discriminant-value.rs

@@ -0,0 +1,27 @@
+// Verify that DIEnumerator uses isUnsigned flag when appropriate.
+//
+// compile-flags: -g -C no-prepopulate-passes
+
+#[repr(i64)]
+pub enum I64 {
+    I64Min = std::i64::MIN,
+    I64Max = std::i64::MAX,
+}
+
+#[repr(u64)]
+pub enum U64 {
+    U64Min = std::u64::MIN,
+    U64Max = std::u64::MAX,
+}
+
+fn main() {
+    let _a = I64::I64Min;
+    let _b = I64::I64Max;
+    let _c = U64::U64Min;
+    let _d = U64::U64Max;
+}
+
+// CHECK: !DIEnumerator(name: "I64Min", value: -9223372036854775808)
+// CHECK: !DIEnumerator(name: "I64Max", value: 9223372036854775807)
+// CHECK: !DIEnumerator(name: "U64Min", value: 0, isUnsigned: true)
+// CHECK: !DIEnumerator(name: "U64Max", value: 18446744073709551615, isUnsigned: true)