[beta-1.72] Pre-commit test for issue 114312.

We show this miscompilation in this commit.

tests/codegen/issues/issue-114312.rs

@@ -0,0 +1,27 @@
+// compile-flags: -O
+// min-system-llvm-version: 17
+// only-x86_64-unknown-linux-gnu
+
+// We want to check that this function does not mis-optimize to loop jumping.
+
+#![crate_type = "lib"]
+
+#[repr(C)]
+pub enum Expr {
+    Sum,
+    // must have more than usize data
+    Sub(usize, u8),
+}
+
+#[no_mangle]
+pub extern "C" fn issue_114312(expr: Expr) {
+    // CHECK-LABEL: @issue_114312(
+    // CHECK-SAME: readonly
+    // CHECK-SAME: byval
+    // CHECK: bb1:
+    // CHECK-NEXT: br label %bb1
+    match expr {
+        Expr::Sum => {}
+        Expr::Sub(_, _) => issue_114312(Expr::Sum),
+    }
+}