[clang] [CIR][AArch64] Lower NEON vsli/vsliq intrinsics (PR #198309)

[Jiahao Guo via cfe-commits]

E00N777 wrote:

> > Yes, I tried removing the bit-cast for these non-8-byte elements, but the tests failed — maybe I overlooked something. I'll revisit it this week and write a more detailed summary so it's easier for you to review.
> 
> Which test failed? I commented the bitcasts out myself and everything worked 🤔 It's possible that I am doing something wrong or missing something. Let's get to the bottom of this mystery!

Sorry for the late reply.
I previously misunderstood your suggestion.in the lowering logic in `llvm-project/clang/lib/CIR/CodeGen/CIRGenBuiltinAArch64.cpp`,those two line `bitcast` is indeed no-need. I mistakenly thought earlier that you were asking about the `bitcast` in the checkline. I'm really sorry.

https://github.com/llvm/llvm-project/pull/198309