https://www.learning2.de/cs/partdiff/>Clang also supports these intrinsics, but lowers most of them only to the corresponding LLVM IR instructions. Consequently, as optimizations in Clang are performed on the level of the LLVM IR, the produced assembly code diverges from the original code. This implies that the intrinsics are not as useful as for compilers like GCC, and the programs produced by Clang are in many cases slower than GCC-compiled programs if intrinsics are employed.