With certain short loops it's still broken, and rust had to workaround it. I've added an autoconf probe for it. https://github.com/rurban/autoconf-archive/blob/master/m4/ax...
For what it's worth, according to Godbolt the test program in your probe seems to work correctly for Clang 12.0.0 and later, which IIRC corresponds to when Rust (re-(re-?))enabled emitting noalias.