Add test

tests/codegen/enum-u128.rs

@@ -0,0 +1,27 @@
+// This tests that debug info for "c-like" 128bit enums is properly emitted.
+// This is ignored for the fallback mode on MSVC due to problems with PDB.
+
+//
+// ignore-msvc
+
+// compile-flags: -g -C no-prepopulate-passes
+
+// CHECK-LABEL: @main
+// CHECK: {{.*}}DICompositeType{{.*}}tag: DW_TAG_enumeration_type,{{.*}}name: "Foo",{{.*}}flags: DIFlagEnumClass,{{.*}}
+// CHECK: {{.*}}DIEnumerator{{.*}}name: "Lo",{{.*}}value: 0,{{.*}}
+// CHECK: {{.*}}DIEnumerator{{.*}}name: "Hi",{{.*}}value: 18446744073709551616,{{.*}}
+// CHECK: {{.*}}DIEnumerator{{.*}}name: "Bar",{{.*}}value: 18446745000000000123,{{.*}}
+
+#![allow(incomplete_features)]
+#![feature(repr128)]
+
+#[repr(u128)]
+pub enum Foo {
+    Lo,
+    Hi = 1 << 64,
+    Bar = 18_446_745_000_000_000_123,
+}
+
+pub fn main() {
+    let foo = Foo::Bar;
+}