ARM Cortex-A15 Exynos5 Compiler Benchmarks
For video encoding you might see a small performance improvement under ARM with the newer GNU Compiler Collection release.
The 7-Zip compression performance saw a noticeable drop in performance with the newer release.
It takes longer to build software with the newer GCC 4.7 on ARM, at least for the common PHP package, but it's not incredibly surprising seeing as build times tend to increase when additional optimizations and other features end up being added over time.
Just as we've seen on x86, the C-Ray multi-threaded ray-tracing performance improves dramatically when moving from GCC 4.6 to GCC 4.7.