Intel Core i7-4770K Haswell testing of GCC 4.8.1 and an early GCC 4.9.0 compiler snapshot along with LLVM Clang 3.3 and an LLVM Clang 3.4 development snapshot. Testing with CFLAGS/CXXFLAGS for the Intel Core i7 Haswell CPU of -O3 and -march=core-avx2. Benchmarking by Michael Larabel for a future article on phoronix.com