[clang] [llvm] [CGObjC] Allow clang.arc.attachedcall on -O0 (PR #164875)

[John McCall via cfe-commits]

rjmccall wrote:

Alright, fair enough. In that case, I have no qualms with using this pattern at -O0, since there's no regression from having to kick over to SelectionDAG anyway.

https://github.com/llvm/llvm-project/pull/164875