[clang] [llvm] Revert "CodeGen: Add LibcallLoweringInfo analysis pass (#168622)" (PR #171452)

[Alexey Bataev via llvm-commits]

alexey-bataev wrote:

> > Yep, we see that memcpy intrinsics started to be expanded into loops
> 
> Are you using a custom pass pipeline? You will need something like [halide/Halide#8892](https://github.com/halide/Halide/pull/8892) or all of the libcalls will be marked as unsupported. If you have a custom target you might need to update `RuntimeLibcalls.td` so that memcpy and friends are enabled.
> 
> If this is with upstream clang/flang, this would be more concerning, but it does not seem like there are any regressions there. There are a decent amount of memory libcall lowering tests.

It is flang, at least

https://github.com/llvm/llvm-project/pull/171452