/debug+ was a flag intended to stop optimizations where they may destroy locals. However, it only takes effect when a local crosses the statement boundary -- temps and other unobservable locals are still stack-optimized. Stack locals that live past a single statement ("long lived") tend to be pretty rare as a percentage of total stack-schedulable locals (most locals that can be stack scheduled are temps). If this optimization doesn't have a large effect, maybe it's worth turning off by default?

cc @VSadov