[libcxx] [llvm] [libc] [compiler-rt] [lldb] [clang-tools-extra] [mlir] [clang] [flang] [AArch64] add intrinsic to generate a bfi instruction (PR #79672)

[Simon Pilgrim via cfe-commits]

RKSimon wrote:

@RamaMalladiAWS Do you have examples of the IR that fails to lower to BFI? These things often turn out to be either a missing middle-end canonicalization or maybe a case that could be added to existing pattern matching in the back-end.

https://github.com/llvm/llvm-project/pull/79672