From an Intel Core i7 3770K "Ivy Bridge" system here is an 11-way compiler comparison to look at the performance of these popular code compilers on the latest-generation Intel hardware. Among the compilers being compared on Intel's Ivy Bridge platform are multiple releases of GCC, LLVM/Clang, DragonEgg, PathScale EKOPath, and Open64.
So, when are we finally going to see some PGO benchmarks? On some hardware due to PGO you can get ridiculously high speedups; Michael, why are you consistently ignoring this great (and free!) optimization?