Constant CHECK_ASCENDING_SORTED_U32 

pub const CHECK_ASCENDING_SORTED_U32: &str = "check_ascending_sorted_u32";

Sort-merge sortedness-detection kernel — single-pass adjacent- pair check; atomically writes 0 to a u32 flag on keys[i] > keys[i+1]. Caller initializes flag to 1 before launch, reads result post-launch. Used by the dispatch-site eligibility check at execute_join to validate caller-asserted sortedness before invoking sort_merge_join_v2_inner_u32_1key.