rengolin added inline comments. ================ Comment at: include/clang/Basic/BuiltinsAArch64.def:63 @@ -62,2 +62,3 @@ BUILTIN(__builtin_arm_wsrp, "vcC*vC*", "nc") +BUILTIN(__builtin_thread_pointer, "v*", "") ---------------- Isn't this nothrow, at least? http://reviews.llvm.org/D11535