Comment by jmalicki
9 hours ago
It's not a change in semantics of compiled code. It is only a change of whether or not the code will compile.
9 hours ago
It's not a change in semantics of compiled code. It is only a change of whether or not the code will compile.
Guaranteeing an optimization that otherwise only might run is a change in semantics. The attribute doesn't allow (in any sensible language) the code to simply not compile because the optimizer doesn't feel like it today (or you compiled with -O0), it forces the compiler to not allocate a stack frame wherever the code fits the structure that makes that definitely possible and fails to compile wherever it doesn't (even if after other optimization passes it happens to fit a structure that makes it possible).