diff --git a/compiler/gen_llvm/src/llvm/refcounting.rs b/compiler/gen_llvm/src/llvm/refcounting.rs
index 0a956f8bce..47f2ecf24c 100644
--- a/compiler/gen_llvm/src/llvm/refcounting.rs
+++ b/compiler/gen_llvm/src/llvm/refcounting.rs
@@ -1724,19 +1724,15 @@ fn modify_refcount_union_help<'a, 'ctx, 'env>(
             if let Layout::RecursivePointer = field_layout {
                 panic!("non-recursive tag unions cannot contain naked recursion pointers!");
             } else if field_layout.contains_refcounted() {
-                // crazy hack
-                match field_layout {
-                    Layout::Builtin(Builtin::Str | Builtin::List(_)) => {
-                        use inkwell::attributes::{Attribute, AttributeLoc};
-                        let kind_id = Attribute::get_named_enum_kind_id("noinline");
-                        debug_assert!(kind_id > 0);
-                        let enum_attr = env.context.create_enum_attribute(kind_id, 1);
+                // crazy hack: inlining this function when it decrements a list or string results
+                // in many, many valgrind errors in `--optimize` mode. We do not know why.
+                if let Layout::Builtin(Builtin::Str | Builtin::List(_)) = field_layout {
+                    use inkwell::attributes::{Attribute, AttributeLoc};
+                    let kind_id = Attribute::get_named_enum_kind_id("noinline");
+                    debug_assert!(kind_id > 0);
+                    let enum_attr = env.context.create_enum_attribute(kind_id, 1);
 
-                        fn_val.add_attribute(AttributeLoc::Function, enum_attr);
-                    }
-                    _ => {
-                        // do nothing
-                    }
+                    fn_val.add_attribute(AttributeLoc::Function, enum_attr);
                 }
 
                 let field_ptr = env