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

[Dawei Pan via cfe-commits]

dwpan wrote:

> Hello. Can you explain why this is needed, as opposed to using the equivalent shift/and/ors?

In Verilog/SystemVerilog language, the basic type is bit or bit vector, and length is arbitrary, insert/extract bits are common features in language.  Introducing corresponding intrinsics could help gradually lower it and bring more optimization opportunities in llc.    

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