There were some huge improvements in LLVM’s intrinsics lookup that dramatically reduce object file size and compile time.
Specifically, llvm/IR/Intrinsics.h gained lookupLLVMIntrinsicByName, which replaces 44k lines of tablegen’d code in llvm/IR/Intrinsics.gen with a binary search. It seems to have reduced object size by 400KB and compile time by about 35s. We include Intrinsics.gen in lib/AST/Builtins.cpp.
We should look into cherry-picking those changes into apple/swift-llvm to see if we can benefit from those compile time and size improvements.
The relevant SVN revisions are r258757, r258774, r258871, r258875, and r258897.