After earlier this week running GCC 4.8.2 vs. GCC 4.9 development snapshot benchmarks on the AMD A10-7850K Kaveri APU, up for testing today are new compiler tests from this new high-end APU comparing GCC 4.9 in its current development form to LLVM Clang 3.4. This GCC 4.9 vs. LLVM Clang 3.4 compiler performance comparison is more competitive than some of the past compiler comparisons and does hold a few surprises.
This open-source compiler testing was done from an Ubuntu 14.04 host with the Linux 3.13 kernel while the hardware was the A10-7850K APU on a Gigabyte F2A88XM-D3H motherboard with 8GB of DDR3-2133MHz system memory and Kingston SSD. GCC 4.9.0 20140126 was built from source as was LLVM Clang 3.4, both of which were built in their release/optimized modes. When building out the various Phoronix Test Suite test profiles under each compiler, the same CFLAGS/CXXFLAGS were passed to the compiler.
Right away with PolyBench-C and LAMMPS we see LLVM Clang 3.4 running slightly ahead of GCC 4.9.0 20140126. To see how GCC 4.8.2 performs, see the earlier Kaveri compiler results.
For many of the tests the GCC 4.9 vs. LLVM Clang 3.4 performance was nearly identical.