I said it does not solve such issues, which, at least for my purposes, I can live with (in my case, if it happens I'm about to overflow the stack anyways).
To my knowledge, no, though if it is possible that may be useful. This is why I said its conditionally-supported. If it is possible, then it could be enabled for architectures where it makes sense, rather than leaving it on always, so as to preserve certain optimizations. I could look into it specifically, and respond on the viability of supporting it on rustc's llvm backend at all.