error: unsupported operation: racy imperfectly overlapping atomic access is not possible in the C++20 memory model, and not supported by Miri's weak memory emulation
  --> $DIR/racing_mixed_size.rs:LL:CC
   |
LL |             std::intrinsics::atomic_load_relaxed(hi);
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ racy imperfectly overlapping atomic access is not possible in the C++20 memory model, and not supported by Miri's weak memory emulation
   |
   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
   = note: BACKTRACE:
   = note: inside closure at $DIR/racing_mixed_size.rs:LL:CC

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

error: aborting due to previous error