Richard Guenther of SUSE announced to the mailing list that the second release candidate is available, just two weeks after the first RC. That earlier article goes over many of the changes you can expect from this yearly Free Software Foundation compiler update. There's new CPU support, language improvements, new compiler flags, and other optimizations. GCC 4.7 is shaping up very nicely.
GCC 4.7 RC2 is available for download from GCC mirrors.
While C11 is now where the latest C programming fun is at, for those wondering about the state of C99 language support within the current GCC code-base, there's updated documentation. Joseph Myers of CodeSourcery committed the 4.7 version of C99 status.
Meanwhile, there's already changes coming up for GCC 4.8.
New benchmarks of GCC 4.7 are currently being conducted at Phoronix. These new GCC 4.7 benchmarks will take advantage of the new compiler testing features. Until the new compiler performance results are published, there are older benchmarks of GCC 4.7 from December as well as under AMD's Bulldozer. GCC 4.7 is looking especially good for Intel's Sandy Bridge / Ivy Bridge / Haswell processors.