not a fair comparison
not a fair comparison, but not for the reasons mentioned so far, if you take a close look at GCC 4.9's changes, it shows it's colors at the LTO and at the LTO combined with PGO, and yes there were some changes to other optimizers but they do not appear to be the focus of GCC 4.9.
if you truly want to compare 4.9 to 4.8 or LLVM/Clang, you would enable LTO and PGO on all of them.
that being said, the opposite also applies (compare LLVM/Clang with the focus of this version of Clang to the same aspects of GCC 4.8 and 4.9).
So it is unfair for LLVM/Clang to be compared against a compiler with good multicore support but it isn't unfair when GCC lags behind in compilation time because of some techniques LLVM or its front-end implement but GCC doesn't. Nice logic.
Originally Posted by Marc Driftmeyer
Benchmarks should be carried at its maximum, squeezing the most and best of contenders, and that's how we know GCC still excels at making fast binaries, though slower at getting things done.