[llvm] [ARM] Stop gluing 1-bit shifts (PR #116547)

[Simon Tatham via llvm-commits]

https://github.com/statham-arm approved this pull request.

Thanks – that's a great explanation and I'm glad I asked! I'd guessed your point 1 (scheduling flexibility), but hadn't spotted point 2 at all (eliminating duplication). So this actually gives _more_ benefit than I'd realised.

LGTM, although I've spotted one last _tiny_ nit.

https://github.com/llvm/llvm-project/pull/116547