This was broken by upstream
llvm/llvm-project@dc6d077396. It's easy
enough to use a regex match to support both, so we do that.
r? @nikic
@rustbot label: +llvm-main
There's no need for the `const_eval_select` dance here. And while I originally wrote the `.try_into().unwrap_unchecked()` implementation here, it's kinda a mess in MIR -- this new one is substantially simpler, as shown by the old one being above the inlining threshold but the new one being below it.