Add test for updating enum discriminant through pointer

rust-lang · Aug 1, 2024 · b3c6583 · b3c6583
1 parent c0e3298
commit b3c6583
Showing 1 changed file with 21 additions and 0 deletions.
diff --git a/tests/codegen/ptr-discriminant-update.rs b/tests/codegen/ptr-discriminant-update.rs
@@ -0,0 +1,21 @@
+//@ compile-flags: -O
+// Test for #122600
+
+#![crate_type = "lib"]
+
+pub enum State {
+ A([u8; 753]),
+ B([u8; 753]),
+}
+
+// CHECK-LABEL: @update
+#[no_mangle]
+pub unsafe fn update(s: *mut State) {
+ // CHECK-NEXT: start
+ // CHECK-NOT: alloca
+ // CHECK-NOT: memcpy
+ // CHECK-NEXT: store i8
+ // CHECK-NEXT: ret
+ let State::A(v) = s.read() else { std::hint::unreachable_unchecked() };
+ s.write(State::B(v));
+}