[clang] [llvm] [Clang][ARM] Fix immediate range for NEON widening left-shifts (PR #212459)

[Kieran B via cfe-commits]

kieroxide wrote:

@davemgreen The ACLE has 0..elt defined in it. So this patch is wrong as it is definitely not 0..elt-1. GCC and Clang need to come to an agreement on whether we allow the full range of shifts from 0..(elt*2) -1 or 0..elt. Once this is decided, I will remove or amend this PR.



https://github.com/llvm/llvm-project/pull/212459