LLVM Clang 4.0 is set to be released in February while GCC 7 will be released as stable in March~April. For those curious how both compilers are currently performing, here is our latest installment of GCC vs. LLVM Clang benchmarking on Linux x86_64.
From an Intel Core i7 6800K Broadwell-E box running Ubuntu 16.04, I just wrapped up fresh GCC and Clang C/C++ benchmarks. On the GCC side were 4.9.4, 5.4.0, 6.3.0, and 7.0.0 snapshot. On the LLVM Clang side was Clang 3.9.1 and Clang 4.0.0 SVN.
During the automated compiler benchmarking process, the same CFLAGS/CXXFLAGS were set of "-O3 -march=native." All of the benchmarks were carried out in a fully-automated and reproducible manner using the open-source Phoronix Test Suite benchmarking software.