http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59920
--- Comment #4 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- For C I believe it's valid to jump back into a scope like that. I don't think it affects reuse of stack space, because the variables in the scope that was left have no defined values at longjmp time and so have no defined values on the second return from setjmp.