[clang] [llvm] [RISCV] Preliminary P-ext intrinsics support (PR #174068)

[Craig Topper via cfe-commits]

topperc wrote:

Why are the built in’s using a different naming than the spec? The spec has i32x2 but the builtins use v2i32?

I hope we can use operator+ and operator- on vector types so we don’t need any builtins for padd/psub.

https://github.com/llvm/llvm-project/pull/174068