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

[Rama Malladi via cfe-commits]

RamaMalladiAWS wrote:

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

Hi @davemgreen, one of AWS customers requested for such an intrinsic to be made available so that they could consume it their IR directly. The reasoning they had was to use 1 instruction such `bfi` instead of a combination of `shift`, `and`, `or`.

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