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

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

> Looks like this change increased size/runtime of the code at O0 with the debug info, we see lots of timeouts in the code compiled with -O0 -g options. Shall it be disabled at O0?

I think this should be NFC, assuming everything is working as intended. It seems that in some cases, certain targets are no longer lowering some functions to libcalls. In my case, I'm seeing `llvm.memset` intrinsics in wasm code get lowered to load/store loops rather than to `memset` calls. Currently investigating why the behavior changed there.

https://github.com/llvm/llvm-project/pull/168622