Haswell-Tuned Binaries Are Still Sometimes Faster On AMD Ryzen Than Znver1 Tuning

Yesterday I posted benchmarks of Clang 4 vs. Clang 5 with AMD Ryzen now that LLVM 5 has received the initial AMD Zen "znver1" scheduler model. That scheduler model and improvements to LLVM/Clang 5.0 yielded some performance improvements, but still there are cases where using "-march=haswell" for tuning and running those generated binaries on Ryzen leads to better performance...